A NEW PREDICTIVE MODEL FOR CONGESTION CONTROL IN WIRELESS SENSOR NETWORKS

Directory of Open Access Journals (Sweden)

NAJME TANZADE PANAH

2017-06-01

Full Text Available With the increase of various applications in the domain of wireless sensor networks, the tendency to use wireless sensors has gradually increased in different applications. On the other hand, diverse traffic with different priorities generated by these sensors requires providing adaptive quality of services based on users` needs. In this paper, a congestion control predictor model is proposed for wireless sensor networks, which considers parameters like network energy consumption, packet loss rate and percentage of delivered high and medium priority packets to the destination. This method consists of congestion prevention, congestion control, and energy control plans using shortest path selection algorithm. In the congestion prevention plan, congestion is prevented by investigating the queues length. In the congestion control plan, the congestion is controlled by reducing the transmission rate. Finally, the energy control plan aims to partially balance the energy of nodes to prevent network failures due to node energy outage. Simulation results indicated that the proposed method has a higher efficiency regarding the aforementioned parameters. In addition, comparisons with other well-known methods showed the effectiveness of the proposed method.

Fair and efficient network congestion control based on minority game

Science.gov (United States)

Wang, Zuxi; Wang, Wen; Hu, Hanping; Deng, Zhaozhang

2011-12-01

Low link utility, RTT unfairness and unfairness of Multi-Bottleneck network are the existing problems in the present network congestion control algorithms at large. Through the analogy of network congestion control with the "El Farol Bar" problem, we establish a congestion control model based on minority game(MG), and then present a novel network congestion control algorithm based on the model. The result of simulations indicates that the proposed algorithm can make the achievements of link utility closing to 100%, zero packet lose rate, and small of queue size. Besides, the RTT unfairness and the unfairness of Multi-Bottleneck network can be solved, to achieve the max-min fairness in Multi-Bottleneck network, while efficiently weaken the "ping-pong" oscillation caused by the overall synchronization.

End to end adaptive congestion control in TCP/IP networks

CERN Document Server

Houmkozlis, Christos N

2012-01-01

This book provides an adaptive control theory perspective on designing congestion controls for packet-switching networks. Relevant to a wide range of disciplines and industries, including the music industry, computers, image trading, and virtual groups, the text extensively discusses source oriented, or end to end, congestion control algorithms. The book empowers readers with clear understanding of the characteristics of packet-switching networks and their effects on system stability and performance. It provides schemes capable of controlling congestion and fairness and presents real-world app

The congestion control algorithm based on queue management of each node in mobile ad hoc networks

Science.gov (United States)

Wei, Yifei; Chang, Lin; Wang, Yali; Wang, Gaoping

2016-12-01

This paper proposes an active queue management mechanism, considering the node's own ability and its importance in the network to set the queue threshold. As the network load increases, local congestion of mobile ad hoc network may lead to network performance degradation, hot node's energy consumption increase even failure. If small energy nodes congested because of forwarding data packets, then when it is used as the source node will cause a lot of packet loss. This paper proposes an active queue management mechanism, considering the node's own ability and its importance in the network to set the queue threshold. Controlling nodes buffer queue in different levels of congestion area probability by adjusting the upper limits and lower limits, thus nodes can adjust responsibility of forwarding data packets according to their own situation. The proposed algorithm will slow down the send rate hop by hop along the data package transmission direction from congestion node to source node so that to prevent further congestion from the source node. The simulation results show that, the algorithm can better play the data forwarding ability of strong nodes, protect the weak nodes, can effectively alleviate the network congestion situation.

Mean Field Type Control with Congestion

Energy Technology Data Exchange (ETDEWEB)

Achdou, Yves, E-mail: achdou@ljll.univ-paris-diderot.fr; Laurière, Mathieu [Univ. Paris Diderot, Sorbonne Paris Cité, Laboratoire Jacques-Louis Lions, UMR 7598, UPMC, CNRS (France)

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.

Performance analysis of SS7 congestion controls under sustained overload

Science.gov (United States)

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.

Fair decentralized data-rate congestion control for V2V communications

NARCIS (Netherlands)

Belagal Math, C.; Li, H.; Heemstra De Groot, S.M.; Niemegeers, I.G.M.M.

2017-01-01

Channel congestion is one of the most critical issues in IEEE 802.11p-based vehicular ad hoc networks because congestion may lead to unreliability of applications. As a counter measure, the European Telecommunications Standard Institute (ETSI), proposes a mandatory Decentralized Congestion Control

Controlling chaos in Internet congestion control model

International Nuclear Information System (INIS)

Chen Liang; Wang Xiaofan; Han Zhengzhi

2004-01-01

The TCP end-to-end congestion control plus RED router queue management can be modeled as a discrete-time dynamical system, which may create complex bifurcating and chaotic behavior. Based on the basic features of the TCP-RED model, we propose a time-dependent delayed feedback control algorithm to control chaos in the system by perturbing the accessible RED parameter p max . This method is able to stabilized a router queue occupancy at a level without knowing the exact knowledge of the network. Further, we study the situation of the presence of the UDP traffic

Signalling and obfuscation for congestion control

Science.gov (United States)

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.

Controlling chaos in Internet congestion control model

Energy Technology Data Exchange (ETDEWEB)

Chen Liang E-mail: chenmoon110@yahoo.com.cn; Wang Xiaofan; Han Zhengzhi

2004-07-01

The TCP end-to-end congestion control plus RED router queue management can be modeled as a discrete-time dynamical system, which may create complex bifurcating and chaotic behavior. Based on the basic features of the TCP-RED model, we propose a time-dependent delayed feedback control algorithm to control chaos in the system by perturbing the accessible RED parameter p{sub max}. This method is able to stabilized a router queue occupancy at a level without knowing the exact knowledge of the network. Further, we study the situation of the presence of the UDP traffic.

Research on Analysis Method of Traffic Congestion Mechanism Based on Improved Cell Transmission Model

Directory of Open Access Journals (Sweden)

Hongzhao Dong

2012-01-01

Full Text Available To analyze the spreading regularity of the initial traffic congestion, the improved cell transmission model (CTM is proposed to describe the evolution mechanism of traffic congestion in regional road grid. Ordinary cells and oriented cells are applied to render the crowd roads and their adjacent roads. Therefore the traffic flow could be simulated by these cells. Resorting to the proposed model, the duration of the initial traffic congestion could be predicted and the subsequent secondary congestion could be located. Accordingly, the spatial diffusion of traffic congestion could be estimated. At last, taking a road network region of Hangzhou city as an example, the simulation experiment is implemented to verify the proposed method by PARAMICS software. The result shows that the method could predict the duration of the initial congestion and estimate its spatial diffusion accurately.

TCP Congestion Control for the Networks with Markovian Jump Parameters

Directory of Open Access Journals (Sweden)

MOMENI, H. R.

2011-05-01

Full Text Available This paper is concerned with the problem of TCP congestion control for the class of communication networks with random parameters. The linear dynamic model of TCP New Reno in congestion avoidance mode is considered which contains round trip delays in both state and input. The randomness of link capacity, round trip time delay and the number of TCP sessions is modeled with a continuous-time finite state Markov process. An Active Queue Management (AQM technique is then used to adjust the queue level of the congested link to a predefined value. For this purpose, a dynamic output feedback controller with mode dependent parameters is synthesized to stochastically stabilize the TCP/AQM dynamics. The procedure of the control synthesis is implemented by solving a linear matrix inequality (LMI. The results are tested within a simulation example and the effectiveness of the proposed design method is verified.

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

Science.gov (United States)

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.

Day-Ahead Congestion Management in Distribution Systems through Household Demand Response and Distribution Congestion Prices

DEFF Research Database (Denmark)

Liu, Weijia; Wu, Qiuwei; Wen, Fushuan

2014-01-01

into balancing power might challenge the operation of electric distribution systems and cause congestions. This paper presents a distribution congestion price (DCP) based market mechanism to alleviate possible distribution system congestions. By employing the loca- tional marginal pricing (LMP) model...... is proposed. Finally, a practical Danish 60kV/10.5kV distribution system is employed as the test case to verify the proposed method for mitigating congestion....

A Survey of Congestion Control Techniques and Data Link Protocols in Satellite Networks

OpenAIRE

Fahmy, Sonia; Jain, Raj; Lu, Fang; Kalyanaraman, Shivkumar

1998-01-01

Satellite communication systems are the means of realizing a global broadband integrated services digital network. Due to the statistical nature of the integrated services traffic, the resulting rate fluctuations and burstiness render congestion control a complicated, yet indispensable function. The long propagation delay of the earth-satellite link further imposes severe demands and constraints on the congestion control schemes, as well as the media access control techniques and retransmissi...

Traffic Congestion Evaluation and Signal Control Optimization Based on Wireless Sensor Networks: Model and Algorithms

Directory of Open Access Journals (Sweden)

Wei Zhang

2012-01-01

Full Text Available This paper presents the model and algorithms for traffic flow data monitoring and optimal traffic light control based on wireless sensor networks. Given the scenario that sensor nodes are sparsely deployed along the segments between signalized intersections, an analytical model is built using continuum traffic equation and develops the method to estimate traffic parameter with the scattered sensor data. Based on the traffic data and principle of traffic congestion formation, we introduce the congestion factor which can be used to evaluate the real-time traffic congestion status along the segment and to predict the subcritical state of traffic jams. The result is expected to support the timing phase optimization of traffic light control for the purpose of avoiding traffic congestion before its formation. We simulate the traffic monitoring based on the Mobile Century dataset and analyze the performance of traffic light control on VISSIM platform when congestion factor is introduced into the signal timing optimization model. The simulation result shows that this method can improve the spatial-temporal resolution of traffic data monitoring and evaluate traffic congestion status with high precision. It is helpful to remarkably alleviate urban traffic congestion and decrease the average traffic delays and maximum queue length.

Hybrid control of bifurcation and chaos in stroboscopic model of Internet congestion control system

International Nuclear Information System (INIS)

Ding Dawei; Zhu Jie; Luo Xiaoshu

2008-01-01

Interaction between transmission control protocol (TCP) and random early detection (RED) gateway in the Internet congestion control system has been modelled as a discrete-time dynamic system which exhibits complex bifurcating and chaotic behaviours. In this paper, a hybrid control strategy using both state feedback and parameter perturbation is employed to control the bifurcation and stabilize the chaotic orbits embedded in this discrete-time dynamic system of TCP/RED. Theoretical analysis and numerical simulations show that the bifurcation is delayed and the chaotic orbits are stabilized to a fixed point, which reliably achieves a stable average queue size in an extended range of parameters and even completely eliminates the chaotic behaviour in a particular range of parameters. Therefore it is possible to decrease the sensitivity of RED to parameters. By using the hybrid strategy, we may improve the stability and performance of TCP/RED congestion control system significantly

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

Science.gov (United States)

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.

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

Directory of Open Access Journals (Sweden)

Yifei Lu

2017-01-01

Full Text Available 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.

Design and simulation of airport congestion control algorithms

OpenAIRE

Simaiakis, Ioannis; Balakrishnan, Hamsa

2014-01-01

This paper proposes a stochastic model of runway departures and a dynamic programming algorithm for their control at congested airports. Using a multi-variable state description that includes the capacity forecast, the runway system is modeled as a semi-Markov process. The paper then introduces a queuing system for modeling the controlled departure process that enables the efficient calculation of optimal pushback policies using decomposition techniques. The developed algorithm is simulated a...

Congestion Control and Traffic Scheduling for Collaborative Crowdsourcing in SDN Enabled Mobile Wireless Networks

Directory of Open Access Journals (Sweden)

Dawei Shen

2018-01-01

Full Text Available Currently, a number of crowdsourcing-based mobile applications have been implemented in mobile networks and Internet of Things (IoT, targeted at real-time services and recommendation. The frequent information exchanges and data transmissions in collaborative crowdsourcing are heavily injected into the current communication networks, which poses great challenges for Mobile Wireless Networks (MWN. This paper focuses on the traffic scheduling and load balancing problem in software-defined MWN and designs a hybrid routing forwarding scheme as well as a congestion control algorithm to achieve the feasible solution. The traffic scheduling algorithm first sorts the tasks in an ascending order depending on the amount of tasks and then solves it using a greedy scheme. In the proposed congestion control scheme, the traffic assignment is first transformed into a multiknapsack problem, and then the Artificial Fish Swarm Algorithm (AFSA is utilized to solve this problem. Numerical results on practical network topology reveal that, compared with the traditional schemes, the proposed congestion control and traffic scheduling schemes can achieve load balancing, reduce the probability of network congestion, and improve the network throughput.

Congestion control for vehicular delay tolerant network routing protocols

OpenAIRE

Oham, Chuka Finbars

2014-01-01

The Vehicular Delay Tolerant Network (VDTN) is a special and challenging type of the Delay Tolerant Network because of its high mobility, frequent disconnections and nodal congestion features. These challenging features make it prone to congestion which leads to a considerable amount of message drops in the network. To minimize the impact of congestion in the network, we designed and implemented the Congestion Aware Spray and Wait (CASaW) routing protocol. We varied the buffer sizes of the no...

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

Energy Technology Data Exchange (ETDEWEB)

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

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, environmental 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

Infinite horizon optimal impulsive control with applications to Internet congestion control

Science.gov (United States)

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.

Congestion Control for a Fair Packet Delivery in WSN: From a Complex System Perspective

Directory of Open Access Journals (Sweden)

Daniela Aguirre-Guerrero

2014-01-01

Full Text Available 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.

Indirect control of DSRs for regulating power provision and solving local congestions

DEFF Research Database (Denmark)

Sossan, Fabrizio; Marinelli, Mattia; Costanzo, Giuseppe Tommaso

2013-01-01

Inducing a shift in the electricity consumption using a broadcasted dynamic price for the energy is often proposed as a resource for providing regulating power and it is becoming an increasing research focus for enabling higher penetration of renewable energy in the current power system. This paper...... with the CIGRE’ MV reference network with 346 electrically heated buildings as Demand Side Resources, DSRs. The dynamic hourly price of the regulating power provided by Nord Pool Spot market has been used as indirect control signal for the flexible demand....... shows how using indirect control (or control by price) without any precautions, might easily lead to congestions in nearly saturated distribution grids. An auto tuning local controller which acts on the price signal at distribution level is proposed for solving the congestion. Simulations are performed...

Congestion levies; Congestieheffingen

Energy Technology Data Exchange (ETDEWEB)

Verhoef, E.T. [Vakgroep Ruimtelijke Economie, Vrije Universiteit en Tinbergen Instituut, Amsterdam (Netherlands)

1998-02-20

Traffic jams or congestion can be controlled by means of Pigouvian levies. Congestion costs comprise both time losses as scheduling costs. Because a part of those costs are external costs, the free market output is not Pareto-efficient, and therefore levies are required to recover the efficiency. With some restrictions, road-pricing for the western part of the Netherlands is considered to be a feasible option

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

Science.gov (United States)

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...

Congestion Control Algorithm in Distribution Feeders: Integration in a Distribution Management System

Directory of Open Access Journals (Sweden)

Tine L. Vandoorn

2015-06-01

Full Text Available The increasing share of distributed energy resources poses a challenge to the distribution network operator (DNO to maintain the current availability of the system while limiting the investment costs. Related to this, there is a clear trend in DNOs trying to better monitor their grid by installing a distribution management system (DMS. This DMS enables the DNOs to remotely switch their network or better localize and solve faults. Moreover, the DMS can be used to centrally control the grid assets. Therefore, in this paper, a control strategy is discussed that can be implemented in the DMS for solving current congestion problems posed by the increasing share of renewables in the grid. This control strategy controls wind turbines in order to avoid congestion while mitigating the required investment costs in order to achieve a global cost-efficient solution. Next to the application and objective of the control, the parameter tuning of the control algorithm is discussed.

Bifurcation and stability of an improved time-delayed fluid flow model in internet congestion control

International Nuclear Information System (INIS)

Yu-Liang, Liu; Jie, Zhu; Xiao-Shu, Luo

2009-01-01

Based on the fluid flow time-delayed model proposed by Misra et al in internet congestion control, one modified time-delayed model is presented, where the influence of the communication delay on the router queue length is investigated in detail. The main advantage of the new model is that its stability domain is larger even without an extra controller. By linear stability analysis and numerical simulation, the effectiveness and feasibility of the novel model in internet congestion control are verified

Bifurcation and stability of an improved time-delayed fluid flow model in internet congestion control

Science.gov (United States)

Liu, Yu-Liang; Zhu, Jie; Luo, Xiao-Shu

2009-09-01

Based on the fluid flow time-delayed model proposed by Misra et al in internet congestion control, one modified time-delayed model is presented, where the influence of the communication delay on the router queue length is investigated in detail. The main advantage of the new model is that its stability domain is larger even without an extra controller. By linear stability analysis and numerical simulation, the effectiveness and feasibility of the novel model in internet congestion control are verified.

A Congestion Control System Based on VANET for Small Length Roads

Directory of Open Access Journals (Sweden)

Ruchin Jain

2018-01-01

Full Text Available As vehicle population has been increasing on a daily basis, this leads towards increased number of accidents. To overcome this issue, Vehicular Ad Hoc Network (VANET has come up with lot of novel ideas such as vehicular communication, navigation and traffic controlling. In this study, the main focus is on congestion control at the intersections which result from unclear ahead. For this purpose, a city lane and intersection model has been proposed to manage vehicle mobility. It shows the actual vehicle to vehicle and vehicle to traffic infrastructure communication. The experiment was conducted using Network Simulator 2 (NS 2. The implementation required modelling the road side unit, traffic control unit, and on-board unit along the roadside. In the simulation, including traffic volume, the distance between two signals, end-to-end delay, packet delivery ratio, throughput and packet lost were taken into consideration. These parameters ensure efficient communication between the traffic signals. This results in improved congestion control and road safety, since the vehicles will be signalled not to enter the junction box and information about other vehicles.

An Auto Tuning Substation Peak Shaving Controller for Congestion Management Using Flexible Demand

DEFF Research Database (Denmark)

Sossan, Fabrizio; Marinelli, Mattia

2013-01-01

A closed loop substation peak shaving/congestion management controller for radial distribution networks is presented. The controller it uses an individual control signal in order to shift the consumption of a population of demand side resources, DSRs. The controller auto tunes its parameters on...

Cross-Layer Active Predictive Congestion Control Protocol for Wireless Sensor Networks

Directory of Open Access Journals (Sweden)

Yinfeng Wu

2009-10-01

Full Text Available In wireless sensor networks (WSNs, there are numerous factors that may cause network congestion problems, such as the many-to-one communication modes, mutual interference of wireless links, dynamic changes of network topology and the memory-restrained characteristics of nodes. All these factors result in a network being more vulnerable to congestion. In this paper, a cross-layer active predictive congestion control scheme (CL-APCC for improving the performance of networks is proposed. Queuing theory is applied in the CL-APCC to analyze data flows of a single-node according to its memory status, combined with the analysis of the average occupied memory size of local networks. It also analyzes the current data change trends of local networks to forecast and actively adjust the sending rate of the node in the next period. In order to ensure the fairness and timeliness of the network, the IEEE 802.11 protocol is revised based on waiting time, the number of the node‟s neighbors and the original priority of data packets, which dynamically adjusts the sending priority of the node. The performance of CL-APCC, which is evaluated by extensive simulation experiments. is more efficient in solving the congestion in WSNs. Furthermore, it is clear that the proposed scheme has an outstanding advantage in terms of improving the fairness and lifetime of networks.

Cross-layer active predictive congestion control protocol for wireless sensor networks.

Science.gov (United States)

Wan, Jiangwen; Xu, Xiaofeng; Feng, Renjian; Wu, Yinfeng

2009-01-01

In wireless sensor networks (WSNs), there are numerous factors that may cause network congestion problems, such as the many-to-one communication modes, mutual interference of wireless links, dynamic changes of network topology and the memory-restrained characteristics of nodes. All these factors result in a network being more vulnerable to congestion. In this paper, a cross-layer active predictive congestion control scheme (CL-APCC) for improving the performance of networks is proposed. Queuing theory is applied in the CL-APCC to analyze data flows of a single-node according to its memory status, combined with the analysis of the average occupied memory size of local networks. It also analyzes the current data change trends of local networks to forecast and actively adjust the sending rate of the node in the next period. In order to ensure the fairness and timeliness of the network, the IEEE 802.11 protocol is revised based on waiting time, the number of the node's neighbors and the original priority of data packets, which dynamically adjusts the sending priority of the node. The performance of CL-APCC, which is evaluated by extensive simulation experiments. is more efficient in solving the congestion in WSNs. Furthermore, it is clear that the proposed scheme has an outstanding advantage in terms of improving the fairness and lifetime of networks.

A combined fair decentralized message-rate and data-rate congestion control for V2V communication

NARCIS (Netherlands)

Belagal Math, Chetan; Li, Hong; De Groot, Sonia Heemstra; Niemegeers, Ignas

2018-01-01

Channel congestion Is one of the most critical Issues In IEEE 802.11p-based vehicular ad hoc networks as it leads to unreliability of safety applications. As a counter measure, the European Telecommunications Standard Institute (ETSI), proposes a mandatory Decentralized Congestion Control (DCC)

Mechanisms and management of diuretic resistance in congestive heart failure.

Science.gov (United States)

De Bruyne, L K M

2003-05-01

Diuretic drugs are used almost universally in patients with congestive heart failure, most frequently the potent loop diuretics. Despite their unproven effect on survival, their indisputable efficacy in relieving congestive symptoms makes them first line therapy for most patients. In the treatment of more advanced stages of heart failure diuretics may fail to control salt and water retention despite the use of appropriate doses. Diuretic resistance may be caused by decreased renal function and reduced and delayed peak concentrations of loop diuretics in the tubular fluid, but it can also be observed in the absence of these pharmacokinetic abnormalities. When the effect of a short acting diuretic has worn off, postdiuretic salt retention will occur during the rest of the day. Chronic treatment with a loop diuretic results in compensatory hypertrophy of epithelial cells downstream from the thick ascending limb and consequently its diuretic effect will be blunted. Strategies to overcome diuretic resistance include restriction of sodium intake, changes in dose, changes in timing, and combination diuretic therapy.

Wireless Sensor Network Congestion Control Based on Standard Particle Swarm Optimization and Single Neuron PID.

Science.gov (United States)

Yang, Xiaoping; Chen, Xueying; Xia, Riting; Qian, Zhihong

2018-04-19

Aiming at the problem of network congestion caused by the large number of data transmissions in wireless routing nodes of wireless sensor network (WSN), this paper puts forward an algorithm based on standard particle swarm⁻neural PID congestion control (PNPID). Firstly, PID control theory was applied to the queue management of wireless sensor nodes. Then, the self-learning and self-organizing ability of neurons was used to achieve online adjustment of weights to adjust the proportion, integral and differential parameters of the PID controller. Finally, the standard particle swarm optimization to neural PID (NPID) algorithm of initial values of proportion, integral and differential parameters and neuron learning rates were used for online optimization. This paper describes experiments and simulations which show that the PNPID algorithm effectively stabilized queue length near the expected value. At the same time, network performance, such as throughput and packet loss rate, was greatly improved, which alleviated network congestion and improved network QoS.

Wireless Sensor Network Congestion Control Based on Standard Particle Swarm Optimization and Single Neuron PID

Science.gov (United States)

Yang, Xiaoping; Chen, Xueying; Xia, Riting; Qian, Zhihong

2018-01-01

Aiming at the problem of network congestion caused by the large number of data transmissions in wireless routing nodes of wireless sensor network (WSN), this paper puts forward an algorithm based on standard particle swarm–neural PID congestion control (PNPID). Firstly, PID control theory was applied to the queue management of wireless sensor nodes. Then, the self-learning and self-organizing ability of neurons was used to achieve online adjustment of weights to adjust the proportion, integral and differential parameters of the PID controller. Finally, the standard particle swarm optimization to neural PID (NPID) algorithm of initial values of proportion, integral and differential parameters and neuron learning rates were used for online optimization. This paper describes experiments and simulations which show that the PNPID algorithm effectively stabilized queue length near the expected value. At the same time, network performance, such as throughput and packet loss rate, was greatly improved, which alleviated network congestion and improved network QoS. PMID:29671822

Congestion based mechanism for route discovery in a V2I-V2V system applying smart devices and IoT.

Science.gov (United States)

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

Directory of Open Access Journals (Sweden)

Natalia Parrado

2015-03-01

Full Text Available 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.

Dynamic Traffic Congestion Simulation and Dissipation Control Based on Traffic Flow Theory Model and Neural Network Data Calibration Algorithm

Directory of Open Access Journals (Sweden)

Li Wang

2017-01-01

Full Text Available Traffic congestion is a common problem in many countries, especially in big cities. At present, China’s urban road traffic accidents occur frequently, the occurrence frequency is high, the accident causes traffic congestion, and accidents cause traffic congestion and vice versa. The occurrence of traffic accidents usually leads to the reduction of road traffic capacity and the formation of traffic bottlenecks, causing the traffic congestion. In this paper, the formation and propagation of traffic congestion are simulated by using the improved medium traffic model, and the control strategy of congestion dissipation is studied. From the point of view of quantitative traffic congestion, the paper provides the fact that the simulation platform of urban traffic integration is constructed, and a feasible data analysis, learning, and parameter calibration method based on RBF neural network is proposed, which is used to determine the corresponding decision support system. The simulation results prove that the control strategy proposed in this paper is effective and feasible. According to the temporal and spatial evolution of the paper, we can see that the network has been improved on the whole.

Novel methods of utilizing Jitter for Network Congestion Control

Directory of Open Access Journals (Sweden)

Ivan

2013-12-01

Full Text Available This paper proposes a novel paradigm for network congestion control. Instead of perpetual conflict as in TCP, a proof-of-concept first-ever protocol enabling inter-flow communication without infrastructure support thru a side channel constructed on generic FIFO queue behaviour is presented. This enables independent flows passing thru the same bottleneck queue to communicate and achieve fair capacity sharing and a stable equilibrium state in a rapid fashion.

Rate-based congestion control in networks with smart links, revision. B.S. Thesis - May 1988

Science.gov (United States)

Heybey, Andrew Tyrrell

1990-01-01

The author uses a network simulator to explore rate-based congestion control in networks with smart links that can feed back information to tell senders to adjust their transmission rates. This method differs in a very important way from congestion control in which a congested network component just drops packets - the most commonly used method. It is clearly advantageous for the links in the network to communicate with the end users about the network capacity, rather than the users unilaterally picking a transmission rate. The components in the middle of the network, not the end users, have information about the capacity and traffic in the network. The author experiments with three different algorithms for calculating the control rate to feed back to the users. All of the algorithms exhibit problems in the form of large queues when simulated with a configuration modeling the dynamics of a packet-voice system. However, the problems are not with the algorithms themselves, but with the fact that feedback takes time. If the network steady-state utilization is low enough that it can absorb transients in the traffic through it, then the large queues disappear. If the users are modified to start sending slowly, to allow the network to adapt to a new flow without causing congestion, a greater portion of the network's bandwidth can be used.

Congestion Management Strategies of Real-Time Market

DEFF Research Database (Denmark)

Wang, Qi; Zhang, Chunyu; Ding, Yi

2014-01-01

The high penetration of distributed energy resources (DERs) will significantly challenge the power system operation and control due to their stochastic, intermittent, and fluctuation characteristics. This enhances the difficulty of congestion management of power systems in cross-border electricity...... are introduced with the congestion constraints complied. Pre-Contingency strategy is proposed as the advance preparation for the future congestion, and In-Day re-dispatch is used for regulation. Accordingly, the requirements on facilities considering telemetry and remote control in a fast manner are discussed...

PI Stabilization for Congestion Control of AQM Routers with Tuning Parameter Optimization

Directory of Open Access Journals (Sweden)

S. Chebli

2016-09-01

Full Text Available In this paper, we consider the problem of stabilizing network using a new proportional- integral (PI based congestion controller in active queue management (AQM router; with appropriate model approximation in the first order delay systems, we seek a stability region of the controller by using the Hermite- Biehler theorem, which isapplicable to quasipolynomials. A Genetic Algorithm technique is employed to derive optimal or near optimal PI controller parameters.

Energy Effective Congestion Control for Multicast with Network Coding in Wireless Ad Hoc Network

Directory of Open Access Journals (Sweden)

Chuanxin Zhao

2014-01-01

Full Text Available In order to improve network throughput and reduce energy consumption, we propose in this paper a cross-layer optimization design that is able to achieve multicast utility maximization and energy consumption minimization. The joint optimization of congestion control and power allocation is formulated to be a nonlinear nonconvex problem. Using dual decomposition, a distributed optimization algorithm is proposed to avoid the congestion by control flow rate at the source node and eliminate the bottleneck by allocating the power at the intermediate node. Simulation results show that the cross-layer algorithm can increase network performance, reduce the energy consumption of wireless nodes and prolong the network lifetime, while keeping network throughput basically unchanged.

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

Science.gov (United States)

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.

Hopf bifurcation and uncontrolled stochastic traffic-induced chaos in an RED-AQM congestion control system

International Nuclear Information System (INIS)

Wang Jun-Song; Yuan Rui-Xi; Gao Zhi-Wei; Wang De-Jin

2011-01-01

We study the Hopf bifurcation and the chaos phenomena in a random early detection-based active queue management (RED-AQM) congestion control system with a communication delay. We prove that there is a critical value of the communication delay for the stability of the RED-AQM control system. Furthermore, we show that the system will lose its stability and Hopf bifurcations will occur when the delay exceeds the critical value. When the delay is close to its critical value, we demonstrate that typical chaos patterns may be induced by the uncontrolled stochastic traffic in the RED-AQM control system even if the system is still stable, which reveals a new route to the chaos besides the bifurcation in the network congestion control system. Numerical simulations are given to illustrate the theoretical results. (general)

Congestive index of portal vein

International Nuclear Information System (INIS)

Kim, Won Ho; Kim, H. K.; Lee, S. C.; Han, S. H.; Han, K. H.; Chung, J. B.; Choi, H. J.

1989-01-01

In patients with portal hypertension, the blood flow volume is maintained despite decreased blood flow velocity due to enlargement of the vascular cross sectional area. Thus, the 'congestion index' of the portal vein, which is the ratio between the cross sectional area (cm2) and the blood flow velocity (cm/sec) determined by a Doppler ultrasonography, may be a sensitive index by which to assess portal hypertension. We performed Doppler ultrasonography on 24 normal subjects, 14 patients with biopsy proved chronic active hepatitis and 55 patients with liver cirrhosis in order to assess the diagnostic value of the congestion index. The cross sectional area of the portal vein was significantly enlarged and the mean blood flow velocity was significantly reduced in patients with liver cirrhosis compared with controls. However, the blood flow volume was no difference. The congestion index of the portal vein was significantly increased in patients with liver cirrhosis (0.113+0.035) compared with patients with chronic active hepatitis(0.078+0.029) (p<0.001) and controls (0.053+0.016) (p<0.001). The sensitivity, specificity and predictability of the congestion index for detection of patients with the cirrhosis of the liver were 76.4%, 100% and 100% respectively, when the normal range was set at mean+2SD. The results suggest that the congestion index of the portal vein may pla a significant role in diagnosis of portal hypertensive patients

Evaluation of TCP Congestion Control Algorithms on the Windows Vista Platform

Energy Technology Data Exchange (ETDEWEB)

Li, Yee-Ting; /SLAC

2006-07-07

CTCP, an innovative TCP congestion control algorithm developed by Microsoft, is evaluated and compared to HSTCP and StandardTCP. Tests were performed on the production Internet from Stanford Linear Accelerator Center (SLAC) to various geographically located hosts to give a broad overview of the performances. We find that certain issues were apparent during testing (not directly related to the congestion control algorithms) which may skew results. With this in mind, we find that CTCP performed similarly to HSTCP across a multitude of different network environments. However, to improve the fairness and to reduce the impact of CTCP upon existing StandardTCP traffic, two areas of further research were investigated. Algorithmic additions to CTCP for burst control to reduce the aggressiveness of its cwnd increments demonstrated beneficial improvements in both fairness and throughput over the original CTCP algorithm. Similarly, {gamma} auto-tuning algorithms were investigated to dynamically adapt CTCP flows to their network conditions for optimal performance. While the effects of these auto-tuning algorithms when used in addition to burst control showed little to no benefit to fairness nor throughput for the limited number of network paths tested, one of the auto-tuning algorithms performed such that there was negligible impact upon StandardTCP. With these improvements, CTCP was found to perform better than HSTCP in terms of fairness and similarly in terms of throughput under the production environments tested.

Evaluation of TCP Congestion Control Algorithms on the Windows Vista Platform

International Nuclear Information System (INIS)

Li, Y

2006-01-01

CTCP, an innovative TCP congestion control algorithm developed by Microsoft, is evaluated and compared to HSTCP and StandardTCP. Tests were performed on the production Internet from Stanford Linear Accelerator Center (SLAC) to various geographically located hosts to give a broad overview of the performances. We find that certain issues were apparent during testing (not directly related to the congestion control algorithms) which may skew results. With this in mind, we find that CTCP performed similarly to HSTCP across a multitude of different network environments. However, to improve the fairness and to reduce the impact of CTCP upon existing StandardTCP traffic, two areas of further research were investigated. Algorithmic additions to CTCP for burst control to reduce the aggressiveness of its cwnd increments demonstrated beneficial improvements in both fairness and throughput over the original CTCP algorithm. Similarly, auto-tuning algorithms were investigated to dynamically adapt CTCP flows to their network conditions for optimal performance. Whilst the effects of these auto-tuning algorithms when used in addition to burst control showed little to no benefit to fairness nor throughput for the limited number of network paths tested, one of the auto-tuning algorithms performed such that there was negligible impact upon StandardTCP. With these improvements, CTCP was found to perform better than HSTCP in terms of fairness and similarly in terms of throughput under the production environments tested

Focus on renal congestion in heart failure.

Science.gov (United States)

Afsar, Baris; Ortiz, Alberto; Covic, Adrian; Solak, Yalcin; Goldsmith, David; Kanbay, Mehmet

2016-02-01

Hospitalizations due to heart failure are increasing steadily despite advances in medicine. Patients hospitalized for worsening heart failure have high mortality in hospital and within the months following discharge. Kidney dysfunction is associated with adverse outcomes in heart failure patients. Recent evidence suggests that both deterioration in kidney function and renal congestion are important prognostic factors in heart failure. Kidney congestion in heart failure results from low cardiac output (forward failure), tubuloglomerular feedback, increased intra-abdominal pressure or increased venous pressure. Regardless of the cause, renal congestion is associated with increased morbidity and mortality in heart failure. The impact on outcomes of renal decongestion strategies that do not compromise renal function should be explored in heart failure. These studies require novel diagnostic markers that identify early renal damage and renal congestion and allow monitoring of treatment responses in order to avoid severe worsening of renal function. In addition, there is an unmet need regarding evidence-based therapeutic management of renal congestion and worsening renal function. In the present review, we summarize the mechanisms, diagnosis, outcomes, prognostic markers and treatment options of renal congestion in heart failure.

Congestion management of deregulated power systems by optimal setting of Interline Power Flow Controller using Gravitational Search algorithm

Directory of Open Access Journals (Sweden)

Akanksha Mishra

2017-05-01

Full Text Available In a deregulated electricity market it may at times become difficult to dispatch all the required power that is scheduled to flow due to congestion in transmission lines. An Interline Power Flow Controller (IPFC can be used to reduce the system loss and power flow in the heavily loaded line, improve stability and loadability of the system. This paper proposes a Disparity Line Utilization Factor for the optimal placement and Gravitational Search algorithm based optimal tuning of IPFC to control the congestion in transmission lines. DLUF ranks the transmission lines in terms of relative line congestion. The IPFC is accordingly placed in the most congested and the least congested line connected to the same bus. Optimal sizing of IPFC is carried using Gravitational Search algorithm. A multi-objective function has been chosen for tuning the parameters of the IPFC. The proposed method is implemented on an IEEE-30 bus test system. Graphical representations have been included in the paper showing reduction in LUF of the transmission lines after the placement of an IPFC. A reduction in active power and reactive power loss of the system by about 6% is observed after an optimally tuned IPFC has been included in the power system. The effectiveness of the proposed tuning method has also been shown in the paper through the reduction in the values of the objective functions.

Rerouting algorithms solving the air traffic congestion

Science.gov (United States)

Adacher, Ludovica; Flamini, Marta; Romano, Elpidio

2017-06-01

Congestion in the air traffic network is a problem with an increasing relevance for airlines costs as well as airspace safety. One of the major issue is the limited operative capacity of the air network. In this work an Autonomous Agent approach is proposed to solve in real time the problem of air traffic congestion. The air traffic infrastructures are modeled with a graph and are considered partitioned in different sectors. Each sector has its own decision agent dealing with the air traffic control involved in it. Each agent sector imposes a real time aircraft scheduling to respect both delay and capacity constrains. When a congestion is predicted, a new aircraft scheduling is computed. Congestion is solved when the capacity constrains are satisfied once again. This can be done by delaying on ground aircraft or/and rerouting aircraft and/or postponing the congestion. We have tested two different algorithms that calculate K feasible paths for each aircraft involved in the congestion. Some results are reported on North Italian air space.

Congestion management through topological corrections: A case study of Central Western Europe

International Nuclear Information System (INIS)

Han, Jinil; Papavasiliou, Anthony

2015-01-01

The integration of an increasing amount of renewable generation within Europe is posing operational challenges that require various balancing actions. System operators therefore need to rely increasingly on the active control of the transmission network. Transmission topology control is a fast and economical option to add flexibility to the transmission system. We model the current methodology for controlling congestion in the Central Western European (CWE) market and quantify the benefits of topology control. We also compare the results with a nodal pricing model. Our computational results suggest that topology control can significantly reduce congestion management costs under the current market coupling regime whereas the benefits of topology control are limited under nodal pricing. Topology control emerges as an attractive and implementable means of managing congestion as it provides a significant percentage of the cost savings that would be achieved by overhauling the existing European market design and shifting to a nodal pricing regime. - Highlights: • We present the congestion management model in the CWE region. • The benefits of topology control in the CWE region are quantified. • Topology control significantly reduce congestion under the current market coupling. • The benefits of topology control are limited under the nodal pricing regime. • Network topology control is a promising option for mitigating congestion in Europe.

Transvaginal ultrasound examination of women with and without pelvic venous congestion

International Nuclear Information System (INIS)

Halligan, Steve; Campbell, Deidre; Bartram, Clive I.; Rogers, Vera; El-Haddad, Cadria; Patel, Sujata; Beard, Richard W.

2000-01-01

AIM: To determine if transvaginal ultrasound, including power Doppler examination, can distinguish between women with and without pelvic congestion. MATERIALS AND METHODS: Thirty-six women with pelvic congestion were prospectively examined using transvaginal ultrasonography and standard uterine and ovarian measurements made. Additionally, planimetric measurements of each ovary were taken using an image analysis program to determine the cross-sectional area of ovarian stroma and follicles, if any. Power Doppler images of adnexal vessels were obtained and planimetric estimates of surface area calculated. A congestion score was assigned to each patient, based on vein number, diameter and morphology on grey-scale scanning. Identical measurements were obtained from 19 asymptomatic women and results compared. RESULTS: There was no significant difference between women with pelvic congestion and controls with respect to power Doppler or grey-scale images of adnexal vessels, or congestion score. However, women with pelvic congestion had significantly larger and multicystic ovaries when compared to controls. CONCLUSIONS: Transvaginal ultrasound measurements of adnexal vasculature, including power Doppler measurements, cannot reliably distinguish women with pelvic congestion from controls. However, ultrasound may remain useful for diagnosis of pelvic congestion, predominantly because it is able to visualize multi-cystic ovaries in these patients. Halligan, S. (2000).Clinical Radiology 55 , 954-958

Congestive Heart Failure and Central Sleep Apnea.

Science.gov (United States)

Sands, Scott A; Owens, Robert L

2016-03-01

Congestive heart failure (CHF) is among the most common causes of admission to hospitals in the United States, especially in those over age 65. Few data exist regarding the prevalence CHF of Cheyne-Stokes respiration (CSR) owing to congestive heart failure in the intensive care unit (ICU). Nevertheless, CSR is expected to be highly prevalent among those with CHF. Treatment should focus on the underlying mechanisms by which CHF increases loop gain and promotes unstable breathing. Few data are available to determine prevalence of CSR in the ICU, or how CSR might affect clinical management and weaning from mechanical ventilation. Copyright © 2016 Elsevier Inc. All rights reserved.

Pulmonary Vascular Congestion: A Mechanism for Distal Lung Unit Dysfunction in Obesity.

Science.gov (United States)

Oppenheimer, Beno W; Berger, Kenneth I; Ali, Saleem; Segal, Leopoldo N; Donnino, Robert; Katz, Stuart; Parikh, Manish; Goldring, Roberta M

2016-01-01

Obesity is characterized by increased systemic and pulmonary blood volumes (pulmonary vascular congestion). Concomitant abnormal alveolar membrane diffusion suggests subclinical interstitial edema. In this setting, functional abnormalities should encompass the entire distal lung including the airways. We hypothesize that in obesity: 1) pulmonary vascular congestion will affect the distal lung unit with concordant alveolar membrane and distal airway abnormalities; and 2) the degree of pulmonary congestion and membrane dysfunction will relate to the cardiac response. 54 non-smoking obese subjects underwent spirometry, impulse oscillometry (IOS), diffusion capacity (DLCO) with partition into membrane diffusion (DM) and capillary blood volume (VC), and cardiac MRI (n = 24). Alveolar-capillary membrane efficiency was assessed by calculation of DM/VC. Mean age was 45±12 years; mean BMI was 44.8±7 kg/m2. Vital capacity was 88±13% predicted with reduction in functional residual capacity (58±12% predicted). Despite normal DLCO (98±18% predicted), VC was elevated (135±31% predicted) while DM averaged 94±22% predicted. DM/VC varied from 0.4 to 1.4 with high values reflecting recruitment of alveolar membrane and low values indicating alveolar membrane dysfunction. The most abnormal IOS (R5 and X5) occurred in subjects with lowest DM/VC (r2 = 0.31, ppulmonary vascular congestion and failure to achieve the high output state of obesity. Pulmonary vascular congestion and consequent fluid transudation and/or alterations in the structure of the alveolar capillary membrane may be considered often unrecognized causes of airway dysfunction in obesity.

Auctionable fixed transmission rights for congestion management

Science.gov (United States)

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

ACCPndn : adaptive congestion control protocol in named data networking by learning capacities using optimized time-lagged feedforward neural network

OpenAIRE

Karami, Amin

2015-01-01

Named Data Networking (NDN) is a promising network architecture being considered as a possible replacement for the current IP-based Internet infrastructure. However, NDN is subject to congestion when the number of data packets that reach one or various routers in a certain period of time is so high than its queue gets overflowed. To address this problem many congestion control protocols have been proposed in the literature which, however, they are highly sensitive to their control parameters ...

A Credit-Based Congestion-Aware Incentive Scheme for DTNs

Directory of Open Access Journals (Sweden)

Qingfeng Jiang

2016-12-01

Full Text Available In Delay-Tolerant Networks (DTNs, nodes may be selfish and reluctant to expend their precious resources on forwarding messages for others. Therefore, an incentive scheme is necessary to motivate selfish nodes to cooperatively forward messages. However, the current incentive schemes mainly focus on encouraging nodes to participate in message forwarding, without considering the node congestion problem. When many messages are forwarded to the nodes with high connection degree, these nodes will become congested and deliberately discard messages, which will seriously degrade the routing performance and reduce the benefits of other nodes. To address this problem, we propose a credit-based congestion-aware incentive scheme (CBCAIS for DTNs. In CBCAIS, a check and punishment mechanism is proposed to prevent forwarding nodes from deliberately discarding message. In addition, a message acceptance selection mechanism is proposed to allow the nodes to decide whether to accept other messages, according to self congestion degree. The experimental results show that CBCAIS can effectively stimulate selfish nodes to cooperatively forward messages, and achieve a higher message delivery ratio with lower overhead ratio, compared with other schemes.

Framework for Traffic Congestion Management

Directory of Open Access Journals (Sweden)

Mahmud Hassan TALUKDAR

2013-06-01

Full Text Available Traffic Congestion is one of many serious global problems in all great cities resulted from rapid urbanization which always exert negative externalities upon society. The solution of traffic congestion is highly geocentric and due to its heterogeneous nature, curbing congestion is one of the hard tasks for transport planners. It is not possible to suggest unique traffic congestion management framework which could be absolutely applied for every great cities. Conversely, it is quite feasible to develop a framework which could be used with or without minor adjustment to deal with congestion problem. So, the main aim of this paper is to prepare a traffic congestion mitigation framework which will be useful for urban planners, transport planners, civil engineers, transport policy makers, congestion management researchers who are directly or indirectly involved or willing to involve in the task of traffic congestion management. Literature review is the main source of information of this study. In this paper, firstly, traffic congestion is defined on the theoretical point of view and then the causes of traffic congestion are briefly described. After describing the causes, common management measures, using world- wide, are described and framework for supply side and demand side congestion management measures are prepared.

Dynamic Power Tariff for Congestion Management in Distribution Networks

DEFF Research Database (Denmark)

Huang, Shaojun; Wu, Qiuwei; Shahidehpour, Mohammad

2018-01-01

This paper proposes dynamic power tariff (DPT), a new concept for congestion management in distribution networks with high penetration of electric vehicles (EVs), and heat pumps (HPs). The DPT concept is proposed to overcome a drawback of the dynamic tariff (DT) method, i.e., DPT can replace...... the price sensitivity parameter in the DT method, which is relatively unrealistic in practice. Based on the control theory, a control model with two control loops, i.e., the power flow control and voltage control, is established to analyze the congestion management process by the DPT method. Furthermore...

SIP Controlled Admission and Preemption

NARCIS (Netherlands)

Babiarz, J.; Chan, K.; Karagiannis, Georgios; Eardley, P

2006-01-01

This framework defines a method of providing Explicit Congestion Control to real-time inelastic traffic like voice and video through the use of session admission control and preemption mechanisms. This approach uses the Pre-Congestion Notification Marking (PCN) [1] mechanism. PCN marking is deployed

Approaching Incast Congestion with Multi-host Ethernet Controllers

CERN Document Server

Jereczek, Grzegorz Edmund; The ATLAS collaboration

2018-01-01

The bursty many-to-one communication pattern, typical for data acquisition systems, but also present in datacenter networks, is particularly demanding for commodity TCP/IP and Ethernet technologies. We expand our study of building incast-resistant networks based on software switches running on commercial-off-the-shelf servers. In this paper we provide the estimates for costs and physical area required to build such a network. Our estimates indicate that our proposed design offers significant cost advantage over traditional solutions, but higher space utilisation. Next, we show how the latter can be improved with multi-host Ethernet controllers, as an alternative to typical network interface cards. This can also make software switching easier to adapt in datacenter as a solution for incast congestion. We confirm the capabilities for incast-avoidance by evaluating the performance of a reference platform.

Approaching Incast Congestion with Multi-host Ethernet Controllers

CERN Document Server

AUTHOR|(SzGeCERN)698154; The ATLAS collaboration; Lehmann Miotto, Giovanna; Malone, David; Walukiewicz, Miroslaw

2017-01-01

The bursty many-to-one communication pattern, typical for data acquisition systems, but also present in datacenter networks, is particularly demanding for commodity TCP/IP and Ethernet technologies. We expand our study of building incast-resistant networks based on software switches running on commercial-off-the-shelf servers. In this paper we provide the estimates for costs and physical area required to build such a network. Our estimates indicate that our proposed design offers significant cost advantage over traditional solutions, but higher space utilisation. Next, we show how the latter can be improved with multi-host Ethernet controllers, as an alternative to typical network interface cards. This can also make software switching easier to adapt in datacenter as a solution for incast congestion. We confirm the capabilities for incast-avoidance by evaluating the performance of a reference platform.

Demonstration of Market-Based Real-Time Electricity Pricing on a Congested Feeder

DEFF Research Database (Denmark)

Larsen, Emil Mahler; Pinson, Pierre; le Ray, Guillaume

2015-01-01

Congestion management can delay grid reinforcements needed due to the growth of distributed technologies like photovoltaics and electric vehicles. This paper presents a method of congestion management for low voltage feeders using indirect control from the smart grid demonstration EcoGrid EU, where...... prices to 1900 houses, with a virtual feeder of 28 houses receiving congestion pricing. Simulations are used to calculate the cost from using this congestion management method, while demonstration results indicate that congestion can be managed successfully....

CONGESTION CONTROL IMPROVED QoS ROUTING SCHEME FOR WIRELESS SENSOR NETWORK

OpenAIRE

A. Elakkiya*, B. Santhana Krishnan, Dr. M. Ramaswamy

2016-01-01

Wireless sensor network is distributed self-governing sensors used to monitor the physical conditions of the environment. They are constructed by nodes where each of them is connected to sensors. These sensor nodes acquire real time information and transmit the information. When large number of sensor nodes are active in transmitting the information there is a possibility of congestion in the data packets. Congestion occurs due to buffer overflow, channel contention, packet collision, reporti...

Slot allocation on congested motorways : An alternative to congestion pricing

NARCIS (Netherlands)

Koolstra, K.

1999-01-01

With respect to the prevailing congestion problems in the more urbanised regions of the European Union, transportation planners and policymakers are facing a dilemma. Supply-side measures, i.e. increasing the capacities, might shorten the congestion duration, especially if bottlenecks can be

Towards Scalable Distributed Framework for Urban Congestion Traffic Patterns Warehousing

Directory of Open Access Journals (Sweden)

A. Boulmakoul

2015-01-01

Full Text Available We put forward architecture of a framework for integration of data from moving objects related to urban transportation network. Most of this research refers to the GPS outdoor geolocation technology and uses distributed cloud infrastructure with big data NoSQL database. A network of intelligent mobile sensors, distributed on urban network, produces congestion traffic patterns. Congestion predictions are based on extended simulation model. This model provides traffic indicators calculations, which fuse with the GPS data for allowing estimation of traffic states across the whole network. The discovery process of congestion patterns uses semantic trajectories metamodel given in our previous works. The challenge of the proposed solution is to store patterns of traffic, which aims to ensure the surveillance and intelligent real-time control network to reduce congestion and avoid its consequences. The fusion of real-time data from GPS-enabled smartphones integrated with those provided by existing traffic systems improves traffic congestion knowledge, as well as generating new information for a soft operational control and providing intelligent added value for transportation systems deployment.

A Game Theory Based Congestion Control Protocol for Wireless Personal Area Networks

Directory of Open Access Journals (Sweden)

Chuang Ma

2016-01-01

Full Text Available In wireless sensor networks (WSNs, the presence of congestion increases the ratio of packet loss and energy consumption and reduces the network throughput. Particularly, this situation will be more complex in Internet of Things (IoT environment, which is composed of thousands of heterogeneous nodes. RPL is an IPv6 routing protocol in low power and lossy networks standardized by IETF. However, the RPL can induce problems under network congestion, such as frequently parent changing and throughput degradation. In this paper, we address the congestion problem between parent nodes and child nodes in RPL-enabled networks, which typically consist of low power and resource constraint devices. To mitigate the effect of network congestion, we design a parent-change procedure by game theory strategy, by which the child nodes can change next hop neighbors toward the sink. Comparing to the ContikiRPL implementation, the simulation results show that our protocol can achieve more than two times improvement in throughput and reduce packet loss rate with less increasing of average hop count.

Congestion, air pollution, and road safety in urban areas

Energy Technology Data Exchange (ETDEWEB)

Shefer, Daniel [Department of Urban and Regional Economics and Transport, Technion-Israel Institute of Technology, Haifa (Israel)

1993-06-01

The continuous rapid growth in Vehicle Miles Travelled (VMT), coupled with the rapid increase in traffic congestion on highways of virtually every large urban area, explain a major portion of the observed deterioration of urban air quality. To halt this deterioration process and to secure safe and healthy environments and improve the quality of life in our cities, it is paramount to initiate and implement programs which jointly treat traffic congestion, air quality, and road safety. A host of market-based strategies, driven by price mechanisms, have been proposed as the best and most efficient way to decrease traffic congestion and to reduce vehicle emission. Congestion pricing, emission fees, reducing emissions of high polluting vehicles, and introducing more efficient vehicle and/or fuel technologies are not mutually exclusive strategies and therefore they can, and perhaps should, be employed jointly within an overall strategy. In view of the conflicting objectives which may exist between improving urban air quality and reducing road fatalities and traffic congestion, it is of great importance to thoroughly investigate these functional relationships. The results of such studies will help decision makers identify the `socially optimal level of congestion` which will yield the highest net social benefit. 2 figs., 43 refs.

Local empathy provides global minimization of congestion in communication networks

Science.gov (United States)

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.

How Congested Jakarta is? Perception of Jakarta’s Citizen on Traffic Congestion

Directory of Open Access Journals (Sweden)

Muhammad Halley Yudhistira

2017-11-01

Full Text Available This paper aims to reveal the behavior and perception of Jakarta’s citizens on traffic congestion in Jakarta. Although this approach is somewhat well-developed in behavioral science, its utilization in urban economics study, is still limited. Detecting the traffic congestion and its cause mainly relies on physical (engineering methods, i.e V/C ratio. Here, we define the traffic congestion through two variables; ordinal traffic congestion perception and proportion of expected travel time to perceived travel time. Using a non-probabilistic sampling survey held in one of densest business district in Jakarta called Sudirman-Thamrin Golden Triangle Area; the estimation results show that travel behavior plays a major role in affecting travel time perceptions.

Beaconing Performance in IEEE 802.11p Vehicular Networks: the Effect of Radio Channel Congestion

OpenAIRE

Librino, Francesco; Renda, Maria Elena; Santi, Paolo

2013-01-01

In this paper, we study the performance of the beaconing mechanism underlying active safety vehicular applications in presence of different levels of channel congestion. The importance of this study lies in the fact that channel congestion is considered a major factor influencing communication performance in vehicular networks, and that ours is the first investigation of the effects of congestion based on extensive, real-world measurements. The results of our study reveal that congestion has ...

Dynamics of the congestion control model in underwater wireless sensor networks with time delay

International Nuclear Information System (INIS)

Dong, Tao; Hu, Wenjie; Liao, Xiaofeng

2016-01-01

In this paper, a congestion control model in underwater wireless sensor network with time delay is considered. First, the boundedness of the positive equilibrium, where the samples density is positive for each node and the different event flows coexist, is investigated, which implies that the samples density of sensor node cannot exceed the Environmental carrying capacity. Then, by considering the time delay can be regarded as a bifurcating parameter, the dynamical behaviors, which include local stability and Hopf bifurcation, are investigated. It is found that when the communication time delay passes a critical value, the system loses its stability and a Hopf bifurcation occurs, which means the underwater wireless sensor network will be congested, even collapsed. Furthermore, the direction and stability of the bifurcating periodic solutions are derived by applying the normal form theory and the center manifold theorem. Finally, some numerical examples are finally performed to verify the theoretical results.

Managing Recurrent Congestion of Subway Network in Peak Hours with Station Inflow Control

OpenAIRE

Qingru Zou; Xiangming Yao; Peng Zhao; Fei Dou; Taoyuan Yang

2018-01-01

Station inflow control (SIC) is an important and effective method for reducing recurrent congestion during peak hours in the Beijing, Shanghai, and Guangzhou subway systems. This work proposes a practical and efficient method for establishing a static SIC scheme in normal weekdays for large-scale subway networks. First, a traffic assignment model without capacity constraint is utilized to determine passenger flow distributions on the network. An internal relationship between station inflows a...

Congestion with incidents

DEFF Research Database (Denmark)

Fosgerau, Mogens

2010-01-01

This paper considers the impact of random delays during a repeatedly occurring demand peak in a congested facility, such as an airport or an urban road. Congestion is described in the form of a dynamic queue using the Vickrey bottleneck model and assuming Nash equilibrium in departure times. Ever...

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

Science.gov (United States)

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

A Cross-Layer Cooperation Mechanism of Wireless Networks Based on Game Theory

OpenAIRE

Chunsheng, Cui; Yongjian, Yang; Liping, Huang

2014-01-01

To meet the wireless network congestion control problem, we give a definition of congestion degree classification and propose a mechanism of directed cooperative path net, guided by the wireless network’s cross-layer design methods and node cooperation principles. Considering the virtual collision and “starved” phenomenon in congested networks, the QRD mechanism and channel competition mechanism QPCG are proposed, with introducing the game theory into the cross-layer design. Simulation result...

A Novel Congestion Detection Scheme in TCP Over OBS Networks

KAUST Repository

Shihada, Basem

2009-02-01

This paper introduces a novel congestion detection scheme for high-bandwidth TCP flows over optical burst switching (OBS) networks, called statistical additive increase multiplicative decrease (SAIMD). SAIMD maintains and analyzes a number of previous round-trip time (RTTs) at the TCP senders in order to identify the confidence with which a packet loss event is due to network congestion. The confidence is derived by positioning short-term RTT in the spectrum of long-term historical RTTs. The derived confidence corresponding to the packet loss is then taken in the developed policy for TCP congestion window adjustment. We will show through extensive simulation that the proposed scheme can effectively solve the false congestion detection problem and significantly outperform the conventional TCP counterparts without losing fairness. The advantages gained in our scheme are at the expense of introducing more overhead in the SAIMD TCP senders. Based on the proposed congestion control algorithm, a throughput model is formulated, and is further verified by simulation results.

Optimal Tradable Credits Scheme and Congestion Pricing with the Efficiency Analysis to Congestion

Directory of Open Access Journals (Sweden)

Ge Gao

2015-01-01

Full Text Available We allow for three traffic scenarios: the tradable credits scheme, congestion pricing, and no traffic measure. The utility functions of different modes (car, bus, and bicycle are developed by considering the income’s impact on travelers’ behaviors. Their purpose is to analyze the demand distribution of different modes. A social optimization model is built aiming at maximizing the social welfare. The optimal tradable credits scheme (distribution of credits, credits charging, and the credit price, congestion pricing fees, bus frequency, and bus fare are obtained by solving the model. Mode choice behavior under the tradable credits scheme is also studied. Numerical examples are presented to demonstrate the model’s availability and explore the effects of the three schemes on traffic system’s performance. Results show congestion pricing would earn more social welfare than the other traffic measures. However, tradable credits scheme will give travelers more consumer surplus than congestion pricing. Travelers’ consumer surplus with congestion pricing is the minimum, which injures the travelers’ benefits. Tradable credits scheme is considered the best scenario by comparing the three scenarios’ efficiency.

Risk management in electricity markets emphasizing transmission congestion

International Nuclear Information System (INIS)

Kristiansen, Tarjei

2004-01-01

This thesis analyzes transmission pricing, transmission congestion risks and their associated hedging instruments as well as mechanisms for stimulating investments in transmission expansion. An example of risk management in the case of a hydropower producer is included. After liberalization and restructuring of electricity markets, risk management has become important. In particular the thesis analyzes risks due to transmission congestion both in the short- and long-term (investments) for market players such as generators, loads, traders, independent system operators and merchant investors. The work is focused on the northeastern United States electricity markets and the Nordic electricity markets. The first part of the thesis reviews the literature related to the eight research papers in the thesis. This describes the risks that are relevant for an electricity market player and how these can be managed. Next, the basic ingredients of a competitive electricity market are described including the design of the system operator. The transmission pricing method is decisive for hedging against transmission congestion risks and there is an overview of transmission pricing models considering their similarities and differences. Depending on the transmission pricing method used, locational or area (zonal) pricing, the electricity market players can use financial transmission rights or Contracts for Differences, respectively. In the long-term it is important to create mechanisms for investments in transmission expansion and the thesis describes one possible approach and its potential problems. The second part comprises eight research papers. It presents empirical analyses of existing markets for transmission congestion derivatives, theoretical analyses of transmission congestion derivatives, modeling of merchant long-term financial transmission rights, theoretical analysis of the risks of the independent system operator in providing financial transmission rights, an analysis

Dynamic Subsidy Method for Congestion Management in Distribution Networks

DEFF Research Database (Denmark)

Huang, Shaojun; Wu, Qiuwei

2016-01-01

Dynamic subsidy (DS) is a locational price paid by the distribution system operator (DSO) to its customers in order to shift energy consumption to designated hours and nodes. It is promising for demand side management and congestion management. This paper proposes a new DS method for congestion...... management in distribution networks, including the market mechanism, the mathematical formulation through a two-level optimization, and the method solving the optimization by tightening the constraints and linearization. Case studies were conducted with a one node system and the Bus 4 distribution network...... of the Roy Billinton Test System (RBTS) with high penetration of electric vehicles (EVs) and heat pumps (HPs). The case studies demonstrate the efficacy of the DS method for congestion management in distribution networks. Studies in this paper show that the DS method offers the customers a fair opportunity...

OPTIMAL CONGESTION CHARGES IN GENERAL EQUILIBRIUM

Directory of Open Access Journals (Sweden)

Dong-Joo MOON, Ph.D.

2002-01-01

Another maximization problem involves characterizing the second-best optimal solution. In this problem, it is assumed to impose the congestion toll only on a single highway link. This problem yields the second-best congestion toll different from the first-best one. This second-best optimal congestion toll has the structure to reflect its impact on other highway links exempt from the congestion charge program.

FPGA Congestion-Driven Placement Refinement

Energy Technology Data Exchange (ETDEWEB)

Vicente de, J.

2005-07-01

The routing congestion usually limits the complete proficiency of the FPGA logic resources. A key question can be formulated regarding the benefits of estimating the congestion at placement stage. In the last years, it is gaining acceptance the idea of a detailed placement taking into account congestion. In this paper, we resort to the Thermodynamic Simulated Annealing (TSA) algorithm to perform a congestion-driven placement refinement on the top of the common Bounding-Box pre optimized solution. The adaptive properties of TSA allow the search to preserve the solution quality of the pre optimized solution while improving other fine-grain objectives. Regarding the cost function two approaches have been considered. In the first one Expected Occupation (EO), a detailed probabilistic model to account for channel congestion is evaluated. We show that in spite of the minute detail of EO, the inherent uncertainty of this probabilistic model impedes to relieve congestion beyond the sole application of the Bounding-Box cost function. In the second approach we resort to the fast Rectilinear Steiner Regions algorithm to perform not an estimation but a measurement of the global routing congestion. This second strategy allows us to successfully reduce the requested channel width for a set of benchmark circuits with respect to the widespread Versatile Place and Route (VPR) tool. (Author) 31 refs.

Intelligent Traffic Control System Implementation for Traffic Violation Control, Congestion Control and Stolen Vehicle Detection

Directory of Open Access Journals (Sweden)

Swarup Suresh Kulkarni

2017-07-01

Full Text Available Traffic is significant issue in our nation, particularly in urban ranges. Aftereffect of this, activity clog issue happens. Crisis vehicle like rescue vehicle, fire unit, squad cars confront bunches of issue to achieve their goal on account of congested driving conditions, coming about loss of human lives. To minimize this issue we approach new idea name as ”Traffic control framework for blockage control and stolen Vehicle location”. In this framework activity freedom done by transforming Red flag into Green flag. We demonstrate idea of what is called ”Green wave”. Alongside this, we distinguish stolen vehicle by utilizing extremely advantageous RFID innovation. In the event that stolen vehicle is been distinguished, the framework gives ready sign through ringer. Framework sends Message with the assistance of GSM to Police station. In this framework we Use diverse RFID labels for recognizing rescue vehicle, stolen Vehicles. On the off chance that Red flag is on and IR sensor is initiated, then framework gives ringer alarm to movement police. This is novel framework which encourage great answer for comprehend traffic clog.

Road traffic congestion a concise guide

CERN Document Server

Falcocchio, John C

2015-01-01

This book on road traffic congestion in cities and suburbs describes congestion problems and shows how they can be relieved. The first part (Chapters 1 - 3) shows how congestion reflects transportation technologies and settlement patterns. The second part (Chapters 4 - 13) describes the causes, characteristics, and consequences of congestion. The third part (Chapters 14 - 23) presents various relief strategies - including supply adaptation and demand mitigation - for nonrecurring and recurring congestion. The last part (Chapter 24) gives general guidelines for congestion relief and provides a general outlook for the future. The book will be useful for a wide audience - including students, practitioners and researchers in a variety of professional endeavors: traffic engineers, transportation planners, public transport specialists, city planners, public administrators, and private enterprises that depend on transportation for their activities.  

A Multistage Control Mechanism for Group-Based Machine-Type Communications in an LTE System

Directory of Open Access Journals (Sweden)

Wen-Chien Hung

2013-01-01

Full Text Available When machine-type communication (MTC devices perform the long-term evolution (LTE attach procedure without bit rate limitations, they may produce congestion in the core network. To prevent this congestion, the LTE standard suggests using group-based policing to regulate the maximum bit rate of all traffic generated by a group of MTC devices. However, previous studies on the access point name-aggregate maximum bit rate based on group-based policing are relatively limited. This study proposes a multistage control (MSC mechanism to process the operations of maximum bit rate allocation based on resource-use information. For performance evaluation, this study uses a Markov chain with to analyze MTC application in a 3GPP network. Traffic flow simulations in an LTE system indicate that the MSC mechanism is an effective bandwidth allocation method in an LTE system with MTC devices. Experimental results show that the MSC mechanism achieves a throughput 22.5% higher than that of the LTE standard model using the group-based policing, and it achieves a lower delay time and greater long-term fairness as well.

Co-Design Based Lateral Motion Control of All-Wheel-Independent-Drive Electric Vehicles with Network Congestion

Directory of Open Access Journals (Sweden)

Wanke Cao

2017-10-01

Full Text Available All-wheel-independent-drive electric vehicles (AWID-EVs have considerable advantages in terms of energy optimization, drivability and driving safety due to the remarkable actuation flexibility of electric motors. However, in their current implementations, various real-time data in the vehicle control system are exchanged via a controller area network (CAN, which causes network congestion and network-induced delays. These problems could lead to systemic instability and make the system integration difficult. The goal of this paper is to provide a design methodology that can cope with all these challenges for the lateral motion control of AWID-EVs. Firstly, a continuous-time model of an AWID-EV is derived. Then an expression for determining upper and lower bounds on the delays caused by CAN is presented and with which a discrete-time model of the closed-loop CAN system is derived. An expression on the bandwidth utilization is introduced as well. Thirdly, a co-design based scheme combining a period-dependent linear quadratic regulator (LQR and a dynamic period scheduler is designed for the resulting model and the stability criterion is also derived. The results of simulations and hard-in-loop (HIL experiments show that the proposed methodology can effectively guarantee the stability of the vehicle lateral motion control while obviously declining the network congestion.

A Multilevel Congestion-Based Global Router

Directory of Open Access Journals (Sweden)

Logan Rakai

2009-01-01

Full Text Available Routing in nanometer nodes creates an elevated level of importance for low-congestion routing. At the same time, advances in mathematical programming have increased the power to solve complex problems, such as the routing problem. Hence, new routing methods need to be developed that can combine advanced mathematical programming and modeling techniques to provide low-congestion solutions. In this paper, a hierarchical mathematical programming-based global routing technique that considers congestion is proposed. The main contributions presented in this paper include (i implementation of congestion estimation based on actual routing solutions versus purely probabilistic techniques, (ii development of a congestion-based hierarchy for solving the global routing problem, and (iii generation of a robust framework for solving the routing problem using mathematical programming techniques. Experimental results illustrate that the proposed global router is capable of reducing congestion and overflow by as much as 36% compared to the state-of-the-art mathematical programming models.

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

Energy Technology Data Exchange (ETDEWEB)

Achdou, Yves, E-mail: achdou@ljll.univ-paris-diderot.fr; Laurière, Mathieu [Univ. Paris Diderot, Sorbonne Paris Cité, Laboratoire Jacques-Louis Lions, UMR 7598, UPMC, CNRS (France)

2016-12-15

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 conditions are considered: periodic conditions and more realistic boundary conditions associated to state constrained problems. Various test cases and numerical results are presented.

A Review on Natural Ventilation-enabling Façade Noise Control Devices for Congested High-Rise Cities

Directory of Open Access Journals (Sweden)

Shiu-Keung Tang

2017-02-01

Full Text Available This review summarizes the current status of the research and development of natural ventilation-enabling noise control devices for use on the façades of high-rise residential buildings in congested cities. These devices are important for a sustainable urbanized city, as they are supposed to offer good acoustical protection to citizens, allowing for an acceptable level of natural ventilation inside residential units; energy for mechanical ventilation can then be saved. From the information presented in the existing literature, it is concluded that protrusive devices, such as lintels and balconies, are not effective noise screening devices, even if they are installed with sound absorbers and/or reflectors, under the effect of city reverberation. On the contrary, plenum windows and similar structures, which are plenum structures with a staggered air inlet and outlet, are interesting alternatives that are worth rigorous considerations.

Hopf bifurcation in an Internet congestion control model

International Nuclear Information System (INIS)

Li Chunguang; Chen Guanrong; Liao Xiaofeng; Yu Juebang

2004-01-01

We consider an Internet model with a single link accessed by a single source, which responds to congestion signals from the network, and study bifurcation of such a system. By choosing the gain parameter as a bifurcation parameter, we prove that Hopf bifurcation occurs. The stability of bifurcating periodic solutions and the direction of the Hopf bifurcation are determined by applying the normal form theory and the center manifold theorem. Finally, a numerical example is given to verify the theoretical analysis

Identifying mechanisms in the control of quantum dynamics through Hamiltonian encoding

International Nuclear Information System (INIS)

Mitra, Abhra; Rabitz, Herschel

2003-01-01

A variety of means are now available to design control fields for manipulating the evolution of quantum systems. However, the underlying physical mechanisms often remain obscure, especially in the cases of strong fields and high quantum state congestion. This paper proposes a method to quantitatively determine the various pathways taken by a quantum system in going from the initial state to the final target. The mechanism is revealed by encoding a signal in the system Hamiltonian and decoding the resultant nonlinear distortion of the signal in the system time-evolution operator. The relevant interfering pathways determined by this analysis give insight into the physical mechanisms operative during the evolution of the quantum system. A hierarchy of mechanism identification algorithms with increasing ability to extract more detailed pathway information is presented. The mechanism identification concept is presented in the context of analyzing computer simulations of controlled dynamics. As illustrations of the concept, mechanisms are identified in the control of several simple, discrete-state quantum systems. The mechanism analysis tools reveal the roles of multiple interacting quantum pathways to maximally take advantage of constructive and destructive interference. Similar procedures may be applied directly in the laboratory to identify control mechanisms without resort to computer modeling, although this extension is not addressed in this paper

Modelling and experimental study for automated congestion driving

NARCIS (Netherlands)

Urhahne, Joseph; Piastowski, P.; van der Voort, Mascha C.; Bebis, G; Boyle, R.; Parvin, B.; Koracin, D.; Pavlidis, I.; Feris, R.; McGraw, T.; Elendt, M.; Kopper, R.; Ragan, E.; Ye, Z.; Weber, G.

2015-01-01

Taking a collaborative approach in automated congestion driving with a Traffic Jam Assist system requires the driver to take over control in certain traffic situations. In order to warn the driver appropriately, warnings are issued (“pay attention” vs. “take action”) due to a control transition

Congestion Pricing for Aircraft Pushback Slot Allocation.

Science.gov (United States)

Liu, Lihua; Zhang, Yaping; Liu, Lan; Xing, Zhiwei

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.

Congestion Pricing for Aircraft Pushback Slot Allocation.

Directory of Open Access Journals (Sweden)

Lihua Liu

Full Text Available 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.

Auctions for Congestion Management in Distribution Grids

NARCIS (Netherlands)

Philipsen, R.M.; de Weerdt, M.M.; de Vries, L.J.

2016-01-01

Large controllable loads, such as electric vehicles, are increasingly penetrating electricity distribution feeders. To avoid local congestion, their consumption behaviour must be steered, for which a real-time price propagated down from the transmission system does not suffice, as it does not

How Smog Awareness Influences Public Acceptance of Congestion Charge Policies

OpenAIRE

Lingyi Zhou; Yixin Dai

2017-01-01

Although various studies have investigated public acceptance of congestion charge policies, most of them have focused on behavioral and policy-related factors, and did not consider the moderating influence that individual concern about smog and perceived smog risk may have on public acceptance. This paper takes the congestion charge policy in China, targeted at smog and traffic control, and checks how smog awareness—including smog concerns and perceived smog risks, besides behavioral and poli...

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

Directory of Open Access Journals (Sweden)

Junqing Tang

Full Text Available 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

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

Science.gov (United States)

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.

Intermittent renewable generation and network congestion: an empirical analysis of Italian Power Market

International Nuclear Information System (INIS)

Ardian, Faddy; Concettini, Silvia; Creti, Anna

2015-01-01

The literature demonstrates the likely reduction of wholesale electricity prices due to a larger penetration of renewable energy sources (RES). When markets are organized as two or more inter-connected sub-markets within a larger power market the final impact of increasing RES production may be less straightforward given the presence of network constraints. We tests this phenomenon by analyzing the impact of RES production on the probability of congestion and on the size of congestion cost in Italy. Using a database with hourly observations for a five year period we estimate two econometric models on five zonal pairings: a multinomial logit model for the occurrence and direction of congestion and a three stage least square model for the size of congestion costs. The analysis suggests that the effect of a larger local wind and solar supply is to decrease the probability of suffering congestion in entry and to increase the probability of causing a congestion in exit compared to no congestion case. Increasing hydroelectric production has a similar effect. These results hold for both importing and exporting regions, but importing regions are less likely to cause congestion in exit, therefore the installation of new RES capacity in these zones may have a positive effects in terms of flow balance between regions. Concerning the cost level, a larger local RES supply seems to push the congestion cost towards negative values as it decreases the marginal cost for balancing the system. This is true for all zones in the case of explicit congestion cost, but it is only verified in importing regions in the case of implicit congestion cost. This result suggests that the increase of RES production should be promoted in importing zones, but the overall growth should be controlled in order to avoid congestion in the opposite direction. (authors)

The social cost of congestion games by imposing variable delays

Directory of Open Access Journals (Sweden)

Josep Díaz

2017-12-01

Full Text Available In this study, we describe a new coordination mechanism for non-atomic congestion games that leads to a (selfish social cost which is arbitrarily close to the non-selfish optimal. This mechanism incurs no additional cost, in contrast to tolls that typically differ from the social cost as expressed in terms of delays.

Tracing based congestion management and impact of TCPS in competitive power market using MINLP

International Nuclear Information System (INIS)

Kumar, A.; Chanana, S.

2006-01-01

Efficient, fair and secure operation of the competitive power markets are key factors in managing the challenges associated with congestion management. For the system operator, the selection of generators to reschedule their output for effective management of congestion is an important task. This study used a real power flow tracing based approach for selecting the most appropriate generators to reschedule the real power output based on real power flow contribution on a congested line. These generators can be effectively used to reschedule their generation for managing congestion. Using a mixed integer non-linear programming approach for reducing the transmission congestion cost in the system, the impact of Thyristor Controlled Phase Shifter (TCPS) was also investigated and their optimal placement was obtained. The study was carried out on a 39-bus New England system for pool and mix of pool with bilateral and multilateral transactions and their impact on congestion cost. The paper presented the detailed mathematical formulation and modeling process used. It was concluded that for some transactions, the reduction in congestion cost is not very significant. Therefore, system operators should avoid such transactions during congestion to increase market efficiency. 26 refs., 1 tab., 8 figs

Drug therapy for congestive heart failure:appropriate choices can prolong life

International Nuclear Information System (INIS)

Sorrentino, M

1997-01-01

Between one purpose of the insufficiency congestive heart is improve and prolong the quality life. A good multidisciplinary health equipment can help to the improving patients with this disease referred to effective handling interned and ambulatory patients groups. The inhibition mechanism compensate that perpetuate heart congestive insufficiency are a way for reach treatment purposes. Between patients with symptomatic cardiac insufficiency and overload volume is indicated digoxin(Lanoxin) and vasodilators. The enzyme inhibition angiotensin converted improve over life range more than an others vasodilators and is preferred for the systole dysfunction patients

Increased walking variability in elderly persons with congestive heart failure

Science.gov (United States)

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 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).

Distributed Optimization based Dynamic Tariff for Congestion Management in Distribution Networks

DEFF Research Database (Denmark)

Huang, Shaojun; Wu, Qiuwei; Zhao, Haoran

2017-01-01

This paper proposes a distributed optimization based dynamic tariff (DDT) method for congestion management in distribution networks with high penetration of electric vehicles (EVs) and heat pumps (HPs). The DDT method employs a decomposition based optimization method to have aggregators explicitly...... is able to minimize the overall energy consumption cost and line loss cost, which is different from previous decomposition-based methods such as multiagent system methods. In addition, a reconditioning method and an integral controller are introduced to improve convergence of the distributed optimization...... where challenges arise due to multiple congestion points, multiple types of flexible demands and network constraints. The case studies demonstrate the efficacy of the DDT method for congestion management in distribution networks....

Congestion management in liberalized market environment

International Nuclear Information System (INIS)

2006-01-01

This paper is based on the survey conducted by WG C5.4 on congestion management. It describes market conditions and institutional arrangements in the 18 countries participating in the survey, and internal and cross-border congestion management. The interaction with the electricity market is discussed, considering allocation of transmission capacity, market schedule, congestion management tools and payment for the costs incurred. The survey shows that there is a tendency towards the use of market-based methods. (author)

Lung congestion in chronic heart failure: haemodynamic, clinical, and prognostic implications

DEFF Research Database (Denmark)

Melenovsky, Vojtech; Andersen, Mads Jønsson; Andress, Krystof

2015-01-01

AIMS:The goal of the study was to examine the prognostic impact, haemodynamic and clinical features associated with lung congestion in patients with chronic heart failure (HF). METHODS AND RESULTS:HF patients (n = 186) and HF-free controls (n = 21) underwent right heart catheterization...... days (interquartile range 80-875), 59 patients (32%) died. Lung congestion was associated with reduced survival (P renal dysfunction. CONCLUSION:Interstitial lung oedema is associated with pulmonary vascular disease, RV overload...

A Bioinspired Adaptive Congestion-Avoidance Routing for Mobile Ad Hoc Networks

Directory of Open Access Journals (Sweden)

Huang Qiong

2014-01-01

Full Text Available Traditional mobile Ad Hoc network routing protocols are mainly based on the Shortest Path, which possibly results in many congestion nodes that incur routing instability and rerouting. To mitigate the side-efforts, this paper proposed a new bioinspired adaptive routing protocol (ATAR based on a mathematics biology model ARAS. This paper improved the ARAS by reducing the randomness and by introducing a new routing-decision metric “the next-hop fitness” which was denoted as the congestion level of node and the length of routing path. In the route maintenance, the nodes decide to forward the data to next node according to a threshold value of the fitness. In the recovery phase, the node will adopt random manner to select the neighbor as the next hop by calculation of the improved ARAS. With this route mechanism, the ATAR could adaptively circumvent the congestion nodes and the rerouting action is taken in advance. Theoretical analysis and numerical simulation results show that the ATAR protocol outperforms AODV and MARAS in terms of delivery ratio, ETE delay, and the complexity. In particular, ATAR can efficiently mitigate the congestion.

Evaluation of pulmonary congestion by computed tomography

International Nuclear Information System (INIS)

Morooka, Nobuhiro; Yamamoto, Hironori; Yoshida, Hideo; Watanabe, Shigeru; Nakamura, Mamoru

1980-01-01

Pulmonary congestion and pulmonary water distribution of lung fields were evaluated by computed tomography (CT) in 31 patients with congestive heart failure and 19 normal subjects in the supine position. In normal subjects, no difference was noted in the CT value between levels of intercostal spaces as well as between right and left lung fields. CT values were greater in posterior lung fields than in anterior lung fields. A significant increase of CT values at both anterior and posterior lung fields was shown in patients with congestive heart failure compared to normal subjects. In congestive heart failure, pulmonary CT values were correlated with various clinical parameters in the order of chest X-ray findings, NYHA functional classification, venous pressure, right heart catheter findings and circulation time. CT values were decreased with the improvement of parameters by medical treatment. Thus, the increase of pulmonary CT values in patients with congestive heart failure indicated the increase of pulmonary blood content and pulmonary tissue edema in a unit volume. This method was particularly useful for the evaluation of pulmonary congestion and pulmonary water distribution. (author)

Launching automated rotary parking system: Towards traffic congestion free Dhaka city

Science.gov (United States)

Islam, Mohummad Shariful; Tithi, Afshana Morshed; Hossain, Farzad; Shetu, Rifat Sultana; Amin, S. M. Abdullah Al; Chowdhury, Shakia Zannatul Ferdous

2017-12-01

Bangladesh is the most densely populated city in the whole world, which is visible more in the capital city Dhaka. People have to suffer and valuable times are being wasted for this chronic quandary. Lack of proper planning of the city, different speed vehicles on the same road, over population, inadequate road space, unplanned stoppage or parking etc. are responsible for causing the traffic congestion in Dhaka City. Among those insufficient/unplanned parking system is one of the main reasons for causing traffic congestion. The automated rotary car parking system is the best and suitable because of its less utilization of space compared to other systems. It is a friendly parking system due to the non-utilization of noise/pollution related mechanism. The aim of this paper is to develop an automated car parking system with a minimum cost for reducing congestion in Dhaka city.

Nitrendipine binding in congestive heart failure due to myocardial infarction

International Nuclear Information System (INIS)

Dixon, I.M.; Lee, S.L.; Dhalla, N.S.

1990-01-01

Depressed cardiac pump function is the hallmark of congestive heart failure, and it is suspected that decreased influx of Ca2+ into the cardiac cell is responsible for depressed contractile function. Since Ca2+ channels in the sarcolemmal membrane are considered to be an important route for the entry of Ca2+, we examined the status of Ca2+ receptors/channels in failing rat hearts after myocardial infarction of the left ventricular free wall. For this purpose, the left coronary artery was ligated and hearts were examined 4, 8, and 16 weeks later; sham-operated animals served as controls. Hemodynamic assessment revealed decreased total mechanical energy (left ventricular systolic pressure x heart rate), increased left ventricular diastolic pressure, and decreased positive and negative dP/dt in experimental animals at 4, 8, and 16 weeks. Although accumulation of ascites in the abdominal cavity was evident at 4 weeks, other clinical signs of congestive heart failure in experimental rats were evident from the presence of lung congestion and cardiac dilatation at 8 and 16 weeks after induction of myocardial infarction. The density of Ca2+ receptors/channels in crude membranes, as assessed by [3H]nitrendipine binding assay, was found to be decreased in the uninfarcted experimental left ventricle at 8 and 16 weeks; however, no change in the affinity of nitrendipine was evident. A similar depression in the specific binding of another dihydropyridine compound, [3H]PN200-110, was also evident in failing hearts. Brain and skeletal muscle crude membrane preparations, unlike those of the right ventricle and liver, revealed a decrease in Ca2+ receptors/channels density in experimental animals at 16 weeks

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

Science.gov (United States)

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.

Review of Congestion Management Methods for Distribution Networks with High Penetration of Distributed Energy Resources

DEFF Research Database (Denmark)

Huang, Shaojun; Wu, Qiuwei; Liu, Zhaoxi

2014-01-01

This paper reviews the existing congestion management methods for distribution networks with high penetration of DERs documented in the recent research literatures. The congestion management methods for distribution networks reviewed can be grouped into two categories – market methods and direct...... control methods. The market methods consist of dynamic tariff, distribution capacity market, shadow price and flexible service market. The direct control methods are comprised of network reconfiguration, reactive power control and active power control. Based on the review of the existing methods...

Air congestion delay: a review

Directory of Open Access Journals (Sweden)

Daniel Alberto Pamplona

2016-04-01

Full Text Available This article is a literature review of the air congestion delay and its costs. Air congestion is a worldwide problem. Its existence brings costs for airlines and discomfort for passengers. With the increasing demand for air transport, the study of air congestion has attracted the attention of many researchers around the world. The cause for the delays is erroneously attributed only to the lack of infrastructure investments. The literature review shows that other factors such as population growth, increasing standards of living, lack of operational planning and environmental issues exercise decisive influence. Several studies have been conducted in order to analyze and propose solutions to this problem that affects society as a whole.

Understanding congested travel in urban areas

Science.gov (United States)

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.

Advanced carrier sensing to resolve local channel congestion

NARCIS (Netherlands)

Schmidt, Robert K.; Brakemeier, Achim; Leinmüller, Tim; Kargl, Frank; Schäfer, Günther

Communication performance in VANETs under high channel load is significantly degraded due to packet collisions and messages drops, also referred to as local channel congestion. So far, research was focused on the control of transmit power and the limitation of the messages rate to mitigate the

Congestion and cascades in payment systems

Science.gov (United States)

Beyeler, Walter E.; Glass, Robert J.; Bech, Morten L.; Soramäki, Kimmo

2007-10-01

We develop a parsimonious model of the interbank payment system. The model incorporates an endogenous instruction arrival process, a scale-free topology of payments between banks, a fixed total liquidity which limits banks’ capacity to process arriving instructions, and a global market that distributes liquidity. We find that at low liquidity the system becomes congested and payment settlement loses correlation with payment instruction arrival, becoming coupled across the network. The onset of congestion is evidently related to the relative values of three characteristic times: the time for banks’ net position to return to 0, the time for a bank to exhaust its liquidity endowment, and the liquidity market relaxation time. In the congested regime settlement takes place in cascades having a characteristic length scale. A global liquidity market substantially attenuates congestion, requiring only a small fraction of the payment-induced liquidity flow to achieve strong beneficial effects.

Treatment of congestion in upper respiratory diseases

Directory of Open Access Journals (Sweden)

Eli O Meltzer

2010-02-01

Full Text Available Eli O Meltzer1, Fernan Caballero2, Leonard M Fromer3, John H Krouse4, Glenis Scadding51Allergy and Asthma Medical Group and Research Center, San Diego, CA and Department of Pediatrics, University of California, San Diego, USA; 2Allergy and Clinical Immunology Service, Centro Medico-Docente La Trinidad, Caracas, Venezuela; 3David Geffen School of Medicine, University of California, Los Angeles, USA; 4Wayne State University School of Medicine, Detroit, Michigan, USA; 5Department of Allergy and Rhinology, Royal National TNE Hospital, London, UKAbstract: Congestion, as a symptom of upper respiratory tract diseases including seasonal and perennial allergic rhinitis, acute and chronic rhinosinusitis, and nasal polyposis, is principally caused by mucosal inflammation. Though effective pharmacotherapy options exist, no agent is universally efficacious; therapeutic decisions must account for individual patient preferences. Oral H1-antihistamines, though effective for the common symptoms of allergic rhinitis, have modest decongestant action, as do leukotriene receptor antagonists. Intranasal antihistamines appear to improve congestion better than oral forms. Topical decongestants reduce congestion associated with allergic rhinitis, but local adverse effects make them unsuitable for long-term use. Oral decongestants show some efficacy against congestion in allergic rhinitis and the common cold, and can be combined with oral antihistamines. Intranasal corticosteroids have broad anti-inflammatory activities, are the most potent long-term pharmacologic treatment of congestion associated with allergic rhinitis, and show some congestion relief in rhinosinusitis and nasal polyposis. Immunotherapy and surgery may be used in some cases refractory to pharmacotherapy. Steps in congestion management include (1 diagnosis of the cause(s, (2 patient education and monitoring, (3 avoidance of environmental triggers where possible, (4 pharmacotherapy, and (5 immunotherapy

Continuous integration congestion cost allocation based on sensitivity

International Nuclear Information System (INIS)

Wu, Z.Q.; Wang, Y.N.

2004-01-01

Congestion cost allocation is a very important topic in congestion management. Allocation methods based on the Aumann-Shapley value use the discrete numerical integration method, which needs to solve the incremented OPF solution many times, and as such it is not suitable for practical application to large-scale systems. The optimal solution and its sensitivity change tendency during congestion removal using a DC optimal power flow (OPF) process is analysed. A simple continuous integration method based on the sensitivity is proposed for the congestion cost allocation. The proposed sensitivity analysis method needs a smaller computation time than the method based on using the quadratic method and inner point iteration. The proposed congestion cost allocation method uses a continuous integration method rather than discrete numerical integration. The method does not need to solve the incremented OPF solutions; which allows it use in large-scale systems. The method can also be used for AC OPF congestion management. (author)

Shockwave-Based Automated Vehicle Longitudinal Control Algorithm for Nonrecurrent Congestion Mitigation

Directory of Open Access Journals (Sweden)

Liuhui Zhao

2017-01-01

Full Text Available A shockwave-based speed harmonization algorithm for the longitudinal movement of automated vehicles is presented in this paper. In the advent of Connected/Automated Vehicle (C/AV environment, the proposed algorithm can be applied to capture instantaneous shockwaves constructed from vehicular speed profiles shared by individual equipped vehicles. With a continuous wavelet transform (CWT method, the algorithm detects abnormal speed drops in real-time and optimizes speed to prevent the shockwave propagating to the upstream traffic. A traffic simulation model is calibrated to evaluate the applicability and efficiency of the proposed algorithm. Based on 100% C/AV market penetration, the simulation results show that the CWT-based algorithm accurately detects abnormal speed drops. With the improved accuracy of abnormal speed drop detection, the simulation results also demonstrate that the congestion can be mitigated by reducing travel time and delay up to approximately 9% and 18%, respectively. It is also found that the shockwave caused by nonrecurrent congestion is quickly dissipated even with low market penetration.

Sympathetic reflex control of skeletal muscle blood flow in patients with congestive heart failure: evidence for beta-adrenergic circulatory control

International Nuclear Information System (INIS)

Kassis, E.; Jacobsen, T.N.; Mogensen, F.; Amtorp, O.

1986-01-01

Mechanisms controlling forearm muscle vascular resistance (FMVR) during postural changes were investigated in seven patients with severe congestive heart failure (CHF) and in seven control subjects with unimpaired left ventricular function. Relative brachioradial muscle blood flow was determined by the local 133 Xe-washout technique. Unloading of baroreceptors with use of 45 degree upright tilt was comparably obtained in the patients with CHF and control subjects. Control subjects had substantially increased FMVR and heart rate to maintain arterial pressure whereas patients with CHF had decreased FMVR by 51 +/- 11% and had no increase in heart rate despite a fall in arterial pressure during upright tilt. The autoregulatory and local vasoconstrictor reflex responsiveness during postural changes in forearm vascular pressures were intact in both groups. In the patients with CHF, the left axillary nerve plexus was blocked by local anesthesia. No alterations in forearm vascular pressures were observed. This blockade preserved the local regulation of FMVR but reversed the vasodilator response to upright tilt as FMVR increased by 30 +/- 7% (p less than .02). Blockade of central neural impulses to this limb combined with brachial arterial infusions of phentolamine completely abolished the humoral vasoconstriction in the tilted position. Infusions of propranolol to the contralateral brachial artery that did not affect baseline values of heart rate, arterial pressure, or the local reflex regulation of FMVR reversed the abnormal vasodilator response to upright tilt as FMVR increased by 42 +/- 12% (p less than .02). Despite augmented baseline values, forearm venous but not arterial plasma levels of epinephrine increased in the tilted position, as did arteri rather than venous plasma concentrations of norepinephrine in these patients

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

Science.gov (United States)

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 ...

Endogenous scheduling preferences and congestion

DEFF Research Database (Denmark)

Fosgerau, Mogens; Small, Kenneth

2017-01-01

We consider the timing of activities through a dynamic model of commuting with congestion, in which workers care solely about leisure and consumption. Implicit preferences for the timing of the commute form endogenously due to temporal agglomeration economies. Equilibrium exists uniquely and is i......We consider the timing of activities through a dynamic model of commuting with congestion, in which workers care solely about leisure and consumption. Implicit preferences for the timing of the commute form endogenously due to temporal agglomeration economies. Equilibrium exists uniquely...... and is indistinguishable from that of a generalized version of the classical Vickrey bottleneck model, based on exogenous trip-timing preferences, but optimal policies differ: the Vickrey model will misstate the benefits of a capacity increase, it will underpredict the benefits of congestion pricing, and pricing may make...

Managing Recurrent Congestion of Subway Network in Peak Hours with Station Inflow Control

Directory of Open Access Journals (Sweden)

Qingru Zou

2018-01-01

Full Text Available Station inflow control (SIC is an important and effective method for reducing recurrent congestion during peak hours in the Beijing, Shanghai, and Guangzhou subway systems. This work proposes a practical and efficient method for establishing a static SIC scheme in normal weekdays for large-scale subway networks. First, a traffic assignment model without capacity constraint is utilized to determine passenger flow distributions on the network. An internal relationship between station inflows and section flows is then constructed. Second, capacity bottlenecks are identified by considering the transport capacity of each section. Then, a feedback-based bottleneck elimination strategy is established to search target control stations and determine their control time and control strength. To validate the effectiveness of the proposed approach, a decision support system coded in the C# programming language was developed, and the Beijing subway was used as a case study. The results indicate that the proposed method and tool are capable of practical applications, and the generated SIC plan has better performance over the existing SIC plan. This study provides a practical and useful method for operation agencies to construct SIC schemes in the subway system.

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

Science.gov (United States)

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.

Visceral Congestion in Heart Failure: Right Ventricular Dysfunction, Splanchnic Hemodynamics, and the Intestinal Microenvironment.

Science.gov (United States)

Polsinelli, Vincenzo B; Sinha, Arjun; Shah, Sanjiv J

2017-12-01

Visceral venous congestion of the gut may play a key role in the pathogenesis of right-sided heart failure (HF) and cardiorenal syndromes. Here, we review the role of right ventricular (RV) dysfunction, visceral congestion, splanchnic hemodynamics, and the intestinal microenvironment in the setting of right-sided HF. We review recent literature on this topic, outline possible mechanisms of disease pathogenesis, and discuss potential therapeutics. There are several mechanisms linking RV-gut interactions via visceral venous congestion which could result in (1) hypoxia and acidosis in enterocytes, which may lead to enhanced sodium-hydrogen exchanger 3 (NHE3) expression with increased sodium and fluid retention; (2) decreased luminal pH in the intestines, which could lead to alteration of the gut microbiome which could increase gut permeability and inflammation; (3) alteration of renal hemodynamics with triggering of the cardiorenal syndrome; and (4) altered phosphate metabolism resulting in increased pulmonary artery stiffening, thereby increasing RV afterload. A wide variety of therapeutic interventions that act on the RV, pulmonary vasculature, intestinal microenvironment, and the kidney could alter these pathways and should be tested in patients with right-sided HF. The RV-gut axis is an important aspect of HF pathogenesis that deserves more attention. Modulation of the pathways interconnecting the right heart, visceral congestion, and the intestinal microenvironment could be a novel avenue of intervention for right-sided HF.

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

Science.gov (United States)

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.

London-type congestion tax with revenue-recycling

OpenAIRE

Yukihiro Kidokoro

2005-01-01

Road pricing in London attracts a great deal of interest. A challenging aspect of the London scheme is that congestion tax revenue is used to upgrade public transit networks. Although Parry and Bento (2001) show that the total social surplus would increase if congestion tax revenues are used to cut labor taxes, political difficulties exist in implementing revenue-recycling between congestion taxes and labor taxes. Given such political difficulties, the London scheme seems to be very attractiv...

Congestion management considering voltage security of power systems

International Nuclear Information System (INIS)

Esmaili, Masoud; Shayanfar, Heidar Ali; Amjady, Nima

2009-01-01

Congestion in a power network is turned up due to system operating limits. To relieve congestion in a deregulated power market, the system operator pays to market participants, GENCOs and DISCOs, to alter their active powers considering their bids. After performing congestion management, the network may be operated with a low security level because of hitting some flows their upper limit and some voltages their lower limit. In this paper, a novel congestion management method based on the voltage stability margin sensitivities is introduced. Using the proposed method, the system operator so alleviates the congestion that the network can more retain its security. The proposed method not only makes the system more secure after congestion management than other methods already presented for this purpose but also its cost of providing security is lower than the earlier methods. Test results of the proposed method along with the earlier ones on the New-England test system elaborate the efficiency of the proposed method from the viewpoint of providing a better voltage stability margin and voltage profile as well as a lower security cost. (author)

An Efficient Traffic Congestion Monitoring System on Internet of Vehicles

Directory of Open Access Journals (Sweden)

Duc-Binh Nguyen

2018-01-01

Full Text Available Existing intelligent transport systems (ITS do not fully consider and resolve accuracy, instantaneity, and compatibility challenges while resolving traffic congestion in Internet of Vehicles (IoV environments. This paper proposes a traffic congestion monitoring system, which includes data collection, segmented structure establishment, traffic-flow modelling, local segment traffic congestion prediction, and origin-destination traffic congestion service for drivers. Macroscopic model-based traffic-flow factors were formalized on the basis of the analysis results. Fuzzy rules-based local segment traffic congestion prediction was performed to determine the traffic congestion state. To enhance prediction efficiency, this paper presents a verification process for minimizing false predictions which is based on the Rankine-Hugoniot condition and an origin-destination traffic congestion service is also provided. To verify the feasibility of the proposed system, a prototype was implemented. The experimental results demonstrate that the proposed scheme can effectively monitor traffic congestion in terms of accuracy and system response time.

Electricity transmission congestion costs: A review of recent reports

Energy Technology Data Exchange (ETDEWEB)

Lesieutre, Bernard C.; Eto, Joseph H.

2003-10-01

Recently, independent system operators (ISOs) and others have published reports on the costs of transmission congestion. The magnitude of congestion costs cited in these reports has contributed to the national discussion on the current state of U.S. electricity transmission system and whether it provides an adequate platform for competition in wholesale electricity markets. This report reviews reports of congestion costs and begins to assess their implications for the current national discussion on the importance of the U.S. electricity transmission system for enabling competitive wholesale electricity markets. As a guiding principle, we posit that a more robust electricity system could reduce congestion costs; and thereby, (1) facilitate more vibrant and fair competition in wholesale electricity markets, and (2) enable consumers to seek out the lowest prices for electricity. Yet, examining the details suggests that, sometimes, there will be trade-offs between these goals. Therefore, it is essential to understand who pays, how much, and how do they benefit in evaluating options (both transmission and non-transmission alternatives) to address transmission congestion. To describe the differences among published estimates of congestion costs, we develop and motivate three ways by which transmission congestion costs are calculated in restructured markets. The assessment demonstrates that published transmission congestion costs are not directly comparable because they have been developed to serve different purposes. More importantly, critical information needed to make them more comparable, for example in order to evaluate the impacts of options to relieve congestion, is sometimes not available.

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

Science.gov (United States)

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

Radiotherapy for hypersplenism from congestive splenomegaly

International Nuclear Information System (INIS)

Liu, Mu-Tai; Hsieh, Chang-Yo; Chang, Tung-Hao; Lin, Jao-Perng; Huang, Chia-Chun

2004-01-01

We evaluated the effects of splenic irradiation on the common hematological disorders of hypersplenism. From August 2002 to March 2003, five patients with hypersplenism due to congestive splenomegaly underwent splenic irradiation at the Department od Radiation Oncology, Changhua Chirstian Hospital, Taiwan. 3 were males and 2 were females aging from 38 to 66 years. All patients had history of liver cirrhosis. 4 patients underwent thee-dimensional conformal radiotherapy and received conventional radiotherapy with anterior-posterior parallel opposing fields. The followup-period ranged from 1 to 7 months. Thrombocytopenia and splenomegaly were found in all 5 patients by physical examination, hematological test, abdominal sonography and/or abdominal computed tomography. After radiotherapy, thrombocytopenia improved, but leukopenia and anemia did not. No complication due to radiotherapy was found during the follow-up period after splenic irradiation. 2 patients died of hepatocellular carcinoma with active bleeding. One patient died of renal failure due to end-stage renal disease. Based on our results, it seems that splenic irradiation might be effective in treating thrombocytopenia and splenomegaly. Splenic irradiatin seems to be effective for thrombocytopenia, splenomegaly and splenic pain associated with hypersplenism from congenstive splenomegaly. This approach is non-invasive and may be an alternative treatment for splenectomy and splenic embolization for patients with hypersplenism due to congestive splenomegaly. The shortcoming of this study are small sample size, short period of follow-up and lack of randomization. A randomized control trial with more cases and further follow-up of hematological tests and splenic size estimation are warranted to evaluate long term improvement of congestive splenomegaly with thrombocytopeniaafter splenic irradiation

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

Science.gov (United States)

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.

Congestion cost allocation method in a pool model

International Nuclear Information System (INIS)

Jung, H.S.; Hur, D.; Park, J.K.

2003-01-01

The congestion cost caused by transmission capacities and voltage limit is an important issue in a competitive electricity market. To allocate the congestion cost equitably, the active constraints in a constrained dispatch and the sequence of these constraints should be considered. A multi-stage method is proposed which reflects the effects of both the active constraints and the sequence. In a multi-stage method, the types of congestion are analysed in order to consider the sequence, and the relationship between congestion and the active constraints is derived in a mathematical way. The case study shows that the proposed method can give more accurate and equitable signals to customers. (Author)

Dynamic voltage stability constrained congestion management framework for deregulated electricity markets

International Nuclear Information System (INIS)

Amjady, Nima; Hakimi, Mahmood

2012-01-01

Highlights: ► A new congestion management method for electricity markets is proposed. ► The proposed method includes dynamic models of generators and loads. ► Dynamic voltage stability limits are properly modeled in the proposed method. ► The proposed method is compared with several other congestion management methods. ► It leads to a more robust power system with a lower congestion management cost. - Abstract: Congestion management is an important part of power system operation in today deregulated electricity markets. However, congestion management is traditionally performed based on static analysis tools, while these tools may not correctly capture dynamic voltage stability limits of a power system. In this paper, a new congestion management framework considering dynamic voltage stability boundary of power system is proposed. For this purpose, precise dynamic modeling of power system equipment, including generators and loads, is incorporated into the proposed congestion management framework. The proposed method alleviates congestion with a lower congestion management cost and more dynamic voltage stability margin, resulting in a more robust power system, compared with the previous congestion management methods. The validity of proposed congestion management framework is studied based on the New England 39-bus power system. The obtained results confirm the validity of the developed approach.

Driving with a congestion assistant : mental workload and acceptance

NARCIS (Netherlands)

Brookhuis, K.A.; Driel, C. J.G. van; Hof, T.; Arem, B. van; Hoedemaeker, M.

2009-01-01

New driver support systems are developed and introduced to the market at increasing speed. In conditions of traffic congestion drivers may be supported by a" Congestion Assistant", a system that combines the features of a Congestion Warning System (acoustic warning and gas pedal counterforce) and a

Research on Urban Road Traffic Congestion Charging Based on Sustainable Development

Science.gov (United States)

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.

Chest ultrasound and hidden lung congestion in peritoneal dialysis patients.

Science.gov (United States)

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.

Busy hour traffic congestion analysis in mobile macrocells | Ozovehe ...

African Journals Online (AJOL)

In this work, real live traffic data from integrated GSM/GPRS network was used for traffic congestion analysis. The analysis was carried out on 10 congesting cells using network management system (NMS) statistics data span for three years period. Correlation test showed that traffic channel (TCH) congestion depend only ...

Measuring accessibility and congestion in Accra

DEFF Research Database (Denmark)

Møller-Jensen, Lasse; Kofie, Richard Y.; Allotey, Albert N.M.

2012-01-01

Based on extensive gps-measurements, the paper addresses the level of intra-urban accessibility and provides indications of the level of congestion in Accra, Ghana. Traffic flows within the urban area are analyzed with respect to speed, time-of-day, direction, road type and land cover type. The s...... and less during off-peak hours. Delays are frequently found within the inner fringe areas. The paper discusses the methodological potentials and barriers for applying gps tracklog points for analysing traffic flows within an urban road network........ The speed information is extrapolated to cover the total mapped urban road net¬work with time- and direction-specific data. A series of time-distance maps are created using network analysis to illustrate the level of accessibility at different times of the day and at different directions relative...... to the city centre. Peak hour traffic speeds are compared with off-peak levels and theoretical free-flow estimations to provide an indica-tion of the level of congestion. It is found that the core areas are somewhat congested during the day period, while the fringe areas are more congested during peak hours...

Congestion management in a market environment. 2. CIGRE/PES Symposium

International Nuclear Information System (INIS)

2005-01-01

With the opening of electricity markets and changes in the power flows, the issue of available transmission capacity is of more and more importance. Market orientated answers and real-time solutions are implemented or under consideration; diligent management of existing assets and timely investment decisions to increase capacity and to improve the management systems are fundamental. This Symposium discusses the congestion management issue for internal and cross border exchanges, covering six subject areas: international Practices for Congestion Management, tariffs and Pricing, operations for Congestion, information Technology Issues, experiences with Congestion Management, tools for Congestion Management. (author)

Endogenous scheduling preferences and congestion

DEFF Research Database (Denmark)

Fosgerau, Mogens; Small, Kenneth

2010-01-01

and leisure, but agglomeration economies at home and at work lead to scheduling preferences forming endogenously. Using bottleneck congestion technology, we obtain an equilibrium queuing pattern consistent with a general version of the Vickrey bottleneck model. However, the policy implications are different....... Compared to the predictions of an analyst observing untolled equilibrium and taking scheduling preferences as exogenous, we find that both the optimal capacity and the marginal external cost of congestion have changed. The benefits of tolling are greater, and the optimal time varying toll is different....

Managing congestion and intermittent renewable generation in liberalized electricity markets

Energy Technology Data Exchange (ETDEWEB)

Kunz, Friedrich

2013-02-27

This dissertation focuses on selected aspects of network congestion arising in liberalized electricity markets and their management methods with a special weight placed on the integration of increased renewable generation in Europe and Germany. In a first step, the theoretical concepts of congestion management are introduced complemented by a review of current management regimes in selected countries. In the second step, the European approach of managing congestion on international as well as national transmission links is analyzed and the benefits of an integrated congestion management regime are quantified. It is concluded that benefits can be achieved by a closer cooperation of national transmission system operators (TSOs). Thirdly, the German congestion management regime is investigated and the impact of higher renewable generation up to 2020 on congestion management cost is determined. It is shown that a homogeneous and jointly development of generation and transmission infrastructure is a prerequisite for the application of congestion alleviation methods and once they diverge congestion management cost tend to increase substantially. Lastly, the impact of intermittent and uncertain wind generation on electricity markets is analyzed. A stochastic electricity market model is described, which replicates the daily subsequent clearing of reserve, day ahead, and intraday market typical for European countries, and numerical results are presented.

A theory of traffic congestion at moving bottlenecks

Energy Technology Data Exchange (ETDEWEB)

Kerner, Boris S [Daimler AG, GR/PTF, HPC: G021, 71059 Sindelfingen (Germany); Klenov, Sergey L, E-mail: boris.kerner@daimler.co [Department of Physics, Moscow Institute of Physics and Technology, 141700 Dolgoprudny, Moscow Region (Russian Federation)

2010-10-22

The physics of traffic congestion occurring at a moving bottleneck on a multi-lane road is revealed based on the numerical analyses of vehicular traffic with a discrete stochastic traffic flow model in the framework of three-phase traffic theory. We find that there is a critical speed of a moving bottleneck at which traffic breakdown, i.e. a first-order phase transition from free flow to synchronized flow, occurs spontaneously at the moving bottleneck, if the flow rate upstream of the bottleneck is great enough. The greater the flow rate, the higher the critical speed of the moving bottleneck. A diagram of congested traffic patterns at the moving bottleneck is found, which shows regions in the flow-rate-moving-bottleneck-speed plane in which congested patterns emerge spontaneously or can be induced through large enough disturbances in an initial free flow. A comparison of features of traffic breakdown and resulting congested patterns at the moving bottleneck with known ones at an on-ramp (and other motionless) bottleneck is made. Nonlinear features of complex interactions and transformations of congested traffic patterns occurring at on- and off-ramp bottlenecks due to the existence of the moving bottleneck are found. The physics of the phenomenon of traffic congestion due to 'elephant racing' on a multi-lane road is revealed.

A theory of traffic congestion at moving bottlenecks

International Nuclear Information System (INIS)

Kerner, Boris S; Klenov, Sergey L

2010-01-01

The physics of traffic congestion occurring at a moving bottleneck on a multi-lane road is revealed based on the numerical analyses of vehicular traffic with a discrete stochastic traffic flow model in the framework of three-phase traffic theory. We find that there is a critical speed of a moving bottleneck at which traffic breakdown, i.e. a first-order phase transition from free flow to synchronized flow, occurs spontaneously at the moving bottleneck, if the flow rate upstream of the bottleneck is great enough. The greater the flow rate, the higher the critical speed of the moving bottleneck. A diagram of congested traffic patterns at the moving bottleneck is found, which shows regions in the flow-rate-moving-bottleneck-speed plane in which congested patterns emerge spontaneously or can be induced through large enough disturbances in an initial free flow. A comparison of features of traffic breakdown and resulting congested patterns at the moving bottleneck with known ones at an on-ramp (and other motionless) bottleneck is made. Nonlinear features of complex interactions and transformations of congested traffic patterns occurring at on- and off-ramp bottlenecks due to the existence of the moving bottleneck are found. The physics of the phenomenon of traffic congestion due to 'elephant racing' on a multi-lane road is revealed.

A Systems Dynamics Approach to Explore Traffic Congestion and Air Pollution Link in the City of Accra, Ghana

Directory of Open Access Journals (Sweden)

Alex A. N. M. Pappoe

2010-01-01

Full Text Available Economic development and urbanization poses myriad challenges to transportation systems in relation to negative externalities such as traffic congestion and environmental health risks. Accra, the capital of Ghana, faces mounting urban planning problems, for example traffic congestion, air pollution, traffic safety, and land use planning, among others. The paper aims to provide a system dynamics perspective of the problems. Most of the drivers and cause-effect relationships of traffic congestion and its attendant air pollution are investigated and analyzed using causal loop diagrams. The paper further suggests mechanisms by which the negative externalities associated with road transport in the city of Accra can be addressed.

Congestion Pricing for Aircraft Pushback Slot Allocation

Science.gov (United States)

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

A theory of traffic congestion at heavy bottlenecks

Energy Technology Data Exchange (ETDEWEB)

Kerner, Boris S [Daimler AG, GR/ETI, HPC: G021, 71059 Sindelfingen (Germany)

2008-05-30

Spatiotemporal features and physics of vehicular traffic congestion occurring due to heavy highway bottlenecks caused for example by bad weather conditions or accidents are found based on simulations in the framework of three-phase traffic theory. A model of a heavy bottleneck is presented. Under a continuous non-limited increase in bottleneck strength, i.e., when the average flow rate within a congested pattern allowed by the heavy bottleneck decreases continuously up to zero, the evolution of the traffic phases in congested traffic, synchronized flow and wide moving jams, is studied. It is found that at a small enough flow rate within the congested pattern, the pattern exhibits a non-regular structure: a pinch region of synchronized flow within the pattern disappears and appears randomly over time; wide moving jams upstream of the pinch region exhibit a complex non-regular dynamics in which the jams appear and disappear randomly. At greater bottleneck strengths, wide moving jams merge onto a mega-wide moving jam (mega-jam) within which low-speed patterns with a complex non-regular spatiotemporal dynamics occur. We show that when the bottleneck strength is great enough, only the mega-jam survives and synchronized flow remains only within its downstream front separating free flow and congested traffic. Theoretical results presented can explain why no sequence of wide moving jams can often be distinguished in non-homogeneous traffic congestion measured at very heavy bottlenecks caused by bad weather conditions or accidents.

A theory of traffic congestion at heavy bottlenecks

International Nuclear Information System (INIS)

Kerner, Boris S

2008-01-01

Spatiotemporal features and physics of vehicular traffic congestion occurring due to heavy highway bottlenecks caused for example by bad weather conditions or accidents are found based on simulations in the framework of three-phase traffic theory. A model of a heavy bottleneck is presented. Under a continuous non-limited increase in bottleneck strength, i.e., when the average flow rate within a congested pattern allowed by the heavy bottleneck decreases continuously up to zero, the evolution of the traffic phases in congested traffic, synchronized flow and wide moving jams, is studied. It is found that at a small enough flow rate within the congested pattern, the pattern exhibits a non-regular structure: a pinch region of synchronized flow within the pattern disappears and appears randomly over time; wide moving jams upstream of the pinch region exhibit a complex non-regular dynamics in which the jams appear and disappear randomly. At greater bottleneck strengths, wide moving jams merge onto a mega-wide moving jam (mega-jam) within which low-speed patterns with a complex non-regular spatiotemporal dynamics occur. We show that when the bottleneck strength is great enough, only the mega-jam survives and synchronized flow remains only within its downstream front separating free flow and congested traffic. Theoretical results presented can explain why no sequence of wide moving jams can often be distinguished in non-homogeneous traffic congestion measured at very heavy bottlenecks caused by bad weather conditions or accidents

The impact of a congestion assistant on traffic flow efficiency and safety in congested traffic caused by a lane drop

NARCIS (Netherlands)

van Driel, Cornelie; van Arem, Bart

2010-01-01

This article presents the results of a microscopic traffic simulation study conducted to investigate the impact of a Congestion Assistant on traffic efficiency and traffic safety. The Congestion Assistant is an in-vehicle system in which an active pedal supports the driver when approaching

Evaluating congestion management in the Dutch electricity transmission grid

International Nuclear Information System (INIS)

Blijswijk, Martti J. van; Vries, Laurens J. de

2012-01-01

Due to the increase in electricity generation capacity in the Netherlands and a new connection policy, transmission system operator (TSO) TenneT expects a significant increase in congestion in the Dutch transmission grid. To manage this, the Dutch government implemented redispatching, a method which is argued in the literature to potentially impose large congestion costs upon the TSO. A quantitative model of the Dutch electricity system was developed in order to evaluate this method. The outcomes were compared to the performance of three alternative congestion management methods. Regardless of the method, congestion costs were found to be substantially lower than in previous studies. Because combined-cycle gas turbines are the marginal generation technology in almost all cases, the costs of up and down regulation do not differ much. Consequently, the redispatching costs for the TSO are expected to be relatively low, and the opportunities for abuse of market power appear to be limited. While all the evaluated methods are effective and economically efficient, they have significantly different welfare effects. Market splitting creates significantly larger welfare effects than the different varieties of redispatching. - Highlights: ► Congestion management was recently introduced in the Netherlands. ► We quantitatively evaluate the effects of its application. ► We compare this to other congestion management methods. ► Given the specific situation that the marginal cost curve of production is flat, congestion costs are expected to be low.

The economic cost of traffic congestion in Florida.

Science.gov (United States)

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...

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

Science.gov (United States)

2010-04-01

... 23 Highways 1 2010-04-01 2010-04-01 false Federal lands congestion management system (CMS). 970....214 Federal lands congestion management system (CMS). (a) For purposes of this section, congestion...) Develop criteria to determine when a CMS is to be implemented for a specific transportation system; and (2...

23 CFR 972.214 - Federal lands congestion management system (CMS).

Science.gov (United States)

2010-04-01

... 23 Highways 1 2010-04-01 2010-04-01 false Federal lands congestion management system (CMS). 972... § 972.214 Federal lands congestion management system (CMS). (a) For purposes of this section, congestion... interference. For those FWS transportation systems that require a CMS, in both metropolitan and non...

Locating of Series FACTS Devices for Multi-Objective Congestion Management Using Components of Nodal Prices

Directory of Open Access Journals (Sweden)

A. R. Moradi

2017-03-01

Full Text Available Congestion and overloading for lines are the main problems in the exploitation of power grids. The consequences of these problems in deregulated systems can be mentioned as sudden jumps in prices in some parts of the power system, lead to an increase in market power and reduction of competition in it. FACTS devices are efficient, powerful and economical tools in controlling power flows through transmission lines that play a fundamental role in congestion management. However, after removing congestion, power systems due to targeting security restrictions may be managed with a lower voltage or transient stability rather than before removing. Thus, power system stability should be considered within the construction of congestion management. In this paper, a multi-objective structure is presented for congestion management that simultaneously optimizes goals such as total operating cost, voltage and transient security. In order to achieve the desired goals, locating and sizing of series FACTS devices are done with using components of nodal prices and the newly developed grey wolf optimizer (GWO algorithm, respectively. In order to evaluate reliability of mentioned approaches, a simulation is done on the 39-bus New England network.

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

Science.gov (United States)

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.

Research on Congestion Pricing in Multimode Traffic considering Delay and Emission

Directory of Open Access Journals (Sweden)

Hongna Dai

2015-01-01

Full Text Available Rapid development of urbanization and automation has resulted in serious urban traffic congestion and air pollution problems in many Chinese cities recently. As a traffic demand management strategy, congestion pricing is acknowledged to be effective in alleviating the traffic congestion and improving the efficiency of traffic system. This paper proposes an urban traffic congestion pricing model based on the consideration of transportation network efficiency and environment effects. First, the congestion pricing problem under multimode (i.e., car mode and bus mode urban traffic network condition is investigated. Second, a traffic congestion pricing model based on bilevel programming is formulated for a dual-mode urban transportation network, in which the delay and emission of vehicles are considered. Third, an improved mathematical algorithm combining successive average method with the genetic algorithm is proposed to solve the bilevel programming problem. Finally, a numerical experiment based on a hypothetical network is performed to validate the proposed congestion pricing model and algorithm.

Exploring spatio-temporal patterns in traffic congestion data

DEFF Research Database (Denmark)

Kveladze, Irma; Agerholm, Niels; Reinau, Kristian Hegner

2017-01-01

An efficient infrastructure is essential for economic development. However, economic growth has been closely connected to the increasing road transport. This increases traffic congestions significantly, and road network gets near or at its capacity limits. Hence, congestion has become a central...

Green supply chain: Simulating road traffic congestion

Science.gov (United States)

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.

Multi-objective congestion management by modified augmented ε-constraint method

International Nuclear Information System (INIS)

Esmaili, Masoud; Shayanfar, Heidar Ali; Amjady, Nima

2011-01-01

Congestion management is a vital part of power system operations in recent deregulated electricity markets. However, after relieving congestion, power systems may be operated with a reduced voltage or transient stability margin because of hitting security limits or increasing the contribution of risky participants. Therefore, power system stability margins should be considered within the congestion management framework. The multi-objective congestion management provides not only more security but also more flexibility than single-objective methods. In this paper, a multi-objective congestion management framework is presented while simultaneously optimizing the competing objective functions of congestion management cost, voltage security, and dynamic security. The proposed multi-objective framework, called modified augmented ε-constraint method, is based on the augmented ε-constraint technique hybridized by the weighting method. The proposed framework generates candidate solutions for the multi-objective problem including only efficient Pareto surface enhancing the competitiveness and economic effectiveness of the power market. Besides, the relative importance of the objective functions is explicitly modeled in the proposed framework. Results of testing the proposed multi-objective congestion management method on the New-England test system are presented and compared with those of the previous single objective and multi-objective techniques in detail. These comparisons confirm the efficiency of the developed method. (author)

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

Science.gov (United States)

2010-04-01

... 23 Highways 1 2010-04-01 2010-04-01 false Federal lands congestion management system (CMS). 971... Federal lands congestion management system (CMS). (a) For purposes of this section, congestion means the...) Develop criteria to determine when a CMS is to be implemented for a specific FH; and (2) Have CMS coverage...

Data rate based congestion control in V2V communication for traffic safety applications

NARCIS (Netherlands)

Belagal Math, C.; Özgür, A.; Heemstra de Groot, S.M.; Li, H.

2015-01-01

Vehicle-to-Vehicle (V2V) communication systems intend to increase safety and efficiency of the transportation networks. At high vehicle density, the communication channel may become congested, impairing the reliability of the safety applications. As a counter measure, the European Telecommunications

A New TCP Congestion Control Supporting RTT-Fairness

Science.gov (United States)

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.

Avoiding congestion in recommender systems

International Nuclear Information System (INIS)

Ren, Xiaolong; Lü, Linyuan; Liu, Runran; Zhang, Jianlin

2014-01-01

Recommender systems use the historical activities and personal profiles of users to uncover their preferences and recommend objects. Most of the previous methods are based on objects’ (and/or users’) similarity rather than on their difference. Such approaches are subject to a high risk of increasingly exposing users to a narrowing band of popular objects. As a result, a few objects may be recommended to an enormous number of users, resulting in the problem of recommendation congestion, which is to be avoided, especially when the recommended objects are limited resources. In order to quantitatively measure a recommendation algorithm's ability to avoid congestion, we proposed a new metric inspired by the Gini index, which is used to measure the inequality of the individual wealth distribution in an economy. Besides this, a new recommendation method called directed weighted conduction (DWC) was developed by considering the heat conduction process on a user–object bipartite network with different thermal conductivities. Experimental results obtained for three benchmark data sets showed that the DWC algorithm can effectively avoid system congestion, and greatly improve the novelty and diversity, while retaining relatively high accuracy, in comparison with the state-of-the-art methods. (paper)

First-order, stationary mean-field games with congestion

KAUST Repository

Evangelista, David

2018-04-30

Mean-field games (MFGs) are models for large populations of competing rational agents that seek to optimize a suitable functional. In the case of congestion, this functional takes into account the difficulty of moving in high-density areas. Here, we study stationary MFGs with congestion with quadratic or power-like Hamiltonians. First, using explicit examples, we illustrate two main difficulties: the lack of classical solutions and the existence of areas with vanishing densities. Our main contribution is a new variational formulation for MFGs with congestion. With this formulation, we prove the existence and uniqueness of solutions. Finally, we consider applications to numerical methods.

First-order, stationary mean-field games with congestion

KAUST Repository

Evangelista, David; Ferreira, Rita; Gomes, Diogo A.; Nurbekyan, Levon; Voskanyan, Vardan K.

2018-01-01

Mean-field games (MFGs) are models for large populations of competing rational agents that seek to optimize a suitable functional. In the case of congestion, this functional takes into account the difficulty of moving in high-density areas. Here, we study stationary MFGs with congestion with quadratic or power-like Hamiltonians. First, using explicit examples, we illustrate two main difficulties: the lack of classical solutions and the existence of areas with vanishing densities. Our main contribution is a new variational formulation for MFGs with congestion. With this formulation, we prove the existence and uniqueness of solutions. Finally, we consider applications to numerical methods.

Stochastic congestion management in power markets using efficient scenario approaches

International Nuclear Information System (INIS)

Esmaili, Masoud; Amjady, Nima; Shayanfar, Heidar Ali

2010-01-01

Congestion management in electricity markets is traditionally performed using deterministic values of system parameters assuming a fixed network configuration. In this paper, a stochastic programming framework is proposed for congestion management considering the power system uncertainties comprising outage of generating units and transmission branches. The Forced Outage Rate of equipment is employed in the stochastic programming. Using the Monte Carlo simulation, possible scenarios of power system operating states are generated and a probability is assigned to each scenario. The performance of the ordinary as well as Lattice rank-1 and rank-2 Monte Carlo simulations is evaluated in the proposed congestion management framework. As a tradeoff between computation time and accuracy, scenario reduction based on the standard deviation of accepted scenarios is adopted. The stochastic congestion management solution is obtained by aggregating individual solutions of accepted scenarios. Congestion management using the proposed stochastic framework provides a more realistic solution compared with traditional deterministic solutions. Results of testing the proposed stochastic congestion management on the 24-bus reliability test system indicate the efficiency of the proposed framework.

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.

Science.gov (United States)

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...

Efficiency of equilibria in uniform matroid congestion games

NARCIS (Netherlands)

de Jong, Jasper; Klimm, Max; Uetz, Marc Jochen

2016-01-01

Network routing games, and more generally congestion games play a central role in algorithmic game theory, comparable to the role of the traveling salesman problem in combinatorial optimization. It is known that the price of anarchy is independent of the network topology for non-atomic congestion

Research on urban road congestion pricing strategy considering carbon dioxide emissions

NARCIS (Netherlands)

Wang, Y.; Peng, Z.; Wang, K.; Song, X.; Yao, B.; Feng, T.

2015-01-01

Congestion pricing strategy has been recognized as an effective countermeasure in the practical field of urban traffic congestion mitigation. In this paper, a bi-level programming model considering carbon dioxide emission is proposed to mitigate traffic congestion and reduce carbon dioxide

Benefits from coordinating congestion management-The Nordic power market

International Nuclear Information System (INIS)

Bjorndal, Mette; Joernsten, Kurt

2007-01-01

We consider the possibility of improving the utilization of the capacity of the Nordic transmission grid, by improving on the methods for congestion management. We use a simplified model of the Nordic power market, and different load-scenarios are developed in order to illustrate the effects. By improving the coordination of the system operator function, we may achieve that the actual bottlenecks, both as regards to the location and capacity, form the basis for the definition of price areas. This may result in a better partition of the grid, not necessarily following the borders between the control areas of today's system operators. We also consider solving intra zonal bottlenecks 'directly', through the area prices and 'indirectly' by 'moving' internal capacity constraints to the borders between price areas. The examples illustrate that this 'indirect' congestion management may be costly, and result in larger price differences than necessary

Impact of Incidents on Traffic Congestion in Dar es Salaam City

Directory of Open Access Journals (Sweden)

David Mfinanga

2013-06-01

Full Text Available Poorly managed traffic incidents have largely contributed to congestion and delay in the city of Dar es Salaam. A thorough understanding of travel delays caused by incidents is therefore essential for effective countermeasures against the increasing congestion. The method used to determine delays in this research is based on the deterministic queuing theory. Information on incidents was obtained from traffic surveys, traffic police and road users. Counting of the number of vehicles passing the incident location was done on incident and incident-free days. The cumulative traffic counts on incident and incident-free days were then calculated and used to plot the queuing diagram used to determine incident induced delay. This method turned out to be a useful tool for estimating incident induced delay in areas with less sophisticated equipment i.e. where there are no sensors, CCTV cameras, etc. The method provided good estimates of incident induced delay which may help planners and transportation officials in better understanding incident related congestion and in selecting more effective countermeasures against incident related traffic congestion in the city. It was found out that the effects of incidents were different for the different zones, types of incidents and the periods the incident occurred. In addition to the incident duration and the number of vehicles affected, the impact of incidents also depended on availability of alternative routes, number of lanes on the road, discipline of the driver in manoeuvring at incident location and traffic control at the scene.

Statewide GIS mapping of recurring congestion corridors : final report.

Science.gov (United States)

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 ...

Congested Link Inference Algorithms in Dynamic Routing IP Network

Directory of Open Access Journals (Sweden)

Yu Chen

2017-01-01

Full Text Available The performance descending of current congested link inference algorithms is obviously in dynamic routing IP network, such as the most classical algorithm CLINK. To overcome this problem, based on the assumptions of Markov property and time homogeneity, we build a kind of Variable Structure Discrete Dynamic Bayesian (VSDDB network simplified model of dynamic routing IP network. Under the simplified VSDDB model, based on the Bayesian Maximum A Posteriori (BMAP and Rest Bayesian Network Model (RBNM, we proposed an Improved CLINK (ICLINK algorithm. Considering the concurrent phenomenon of multiple link congestion usually happens, we also proposed algorithm CLILRS (Congested Link Inference algorithm based on Lagrangian Relaxation Subgradient to infer the set of congested links. We validated our results by the experiments of analogy, simulation, and actual Internet.

Addressing congestion on single allocation hub-and-spoke networks

Directory of Open Access Journals (Sweden)

Ricardo Saraiva de Camargo

2012-12-01

Full Text Available When considering hub-and-spoke networks with single allocation, the absence of alternative routes makes this kind of systems specially vulnerable to congestion effects. In order to improve the design of such networks, congestion costs must be addressed. This article deploys two different techniques for addressing congestion on single allocation hub-and-spoke networks: the Generalized Benders Decomposition and the Outer Approximation method. Both methods are able to solve large scale instances. Computational experiments show how the adoption of advanced solution strategies, such as Pareto-optimal cut generation on the Master Problem branch-and-bound tree, may be decisive. They also demonstrate that the solution effort is not only associated with the size of the instances, but also with their combination of the installation and congestion costs.

V2X application-reliability analysis of data-rate and message-rate congestion control algorithms

NARCIS (Netherlands)

Math, C. Belagal; Li, H.; Heemstra de Groot, S.M.; Niemegeers, I.G.M.M.

2017-01-01

Intelligent Transportation Systems (ITS) require Vehicle-to-Everything (V2X) communication. In dense traffic, the communication channel may become congested, impairing the reliability of the ITS safety applications. Therefore, European Telecommunications Standard Institute (ETSI) demands

CONGESTION AS A RESULT OF SCHOOL AND SHOPPING CENTER ACTIVITY

Directory of Open Access Journals (Sweden)

Meike Kumaat

2015-12-01

Full Text Available Development of land use in public facilities such as shopping center and school gives an impact on transportation problem in Manado City, North Sulawesi.  To determine factors which have causal relationship with congestion  as a result of school and shopping center activity then it need to be assessed and studied.  Descriptive study with observational survey was used in this study. The study ran Structural Equation Modelling (SEM by using AMOS program. Estimated method was used to calculate sample size then found 300 repondents, comprised : visitors and mall managers, school visitors, parents, school managers, Public Works department, and urban planning department .The study yielded a statistically significant correlation between  school and shopping center activity with congestion s. The result  indicated that school activity was positively related to congestion with p value  at p=0,000 (p ≤ 0,05. Shopping center activity was positively related to congestion with p value  at p=0,000 (p ≤ 0,05. The closer proximity from school to shooping center will causes severe traffic congestion. The relationship between school facility with proximity was found in p value at  p=0,000 (p ≤ 0,05 . The relationship between shopping center facility with proximity was found in p value at  p= 0,020 (p ≤ 0,05. While, the relationship between proximity with congestion was p= 0,008 (p ≤ 0,05. Monastery school and Mega Mall activity were affecting congestion because a closer proximity of two facilities. This indicates that the occurence of traffic congestion in Monastery School  may be dependent on existence of  Piere Tendean road link

The Physics of Traffic Congestion and Road Pricing in Transportation Planning

Science.gov (United States)

Levinson, David

2010-03-01

This presentation develops congestion theory and congestion pricing theory from its micro- foundations, the interaction of two or more vehicles. Using game theory, with a two- player game it is shown that the emergence of congestion depends on the players' relative valuations of early arrival, late arrival, and journey delay. Congestion pricing can be used as a cooperation mechanism to minimize total costs (if returned to the players). The analysis is then extended to the case of the three- player game, which illustrates congestion as a negative externality imposed on players who do not themselves contribute to it. A multi-agent model of travelers competing to utilize a roadway in time and space is presented. To realize the spillover effect among travelers, N-player games are constructed in which the strategy set includes N+1 strategies. We solve the N-player game (for N = 7) and find Nash equilibria if they exist. This model is compared to the bottleneck model. The results of numerical simulation show that the two models yield identical results in terms of lowest total costs and marginal costs when a social optimum exists. Moving from temporal dynamics to spatial complexity, using consistent agent- based techniques, we model the decision-making processes of users and infrastructure owner/operators to explore the welfare consequence of price competition, capacity choice, and product differentiation on congested transportation networks. Component models include: (1) An agent-based travel demand model wherein each traveler has learning capabilities and unique characteristics (e.g. value of time); (2) Econometric facility provision cost models; and (3) Representations of road authorities making pricing and capacity decisions. Different from small-network equilibrium models in prior literature, this agent- based model is applicable to pricing and investment analyses on large complex networks. The subsequent economic analysis focuses on the source, evolution

Traffic Congestion Detection and Avoidance using Vehicular Communication

Directory of Open Access Journals (Sweden)

Ajay Narendrabhai Upadhyaya

2015-01-01

Full Text Available Traffic congestion is a serious problem in big cities. With the number of vehicles increasing rapidly, especially in cities whose economy is booming, the situation is getting even worse. Drivers, unaware of congestion ahead eventually join it and increase the severity of it. The ability of a driver to know the traffic conditions on the roads ahead enables him/her to seek alternate routes through which time and fuel can be saved. Due to recent advancements in vehicular technologies, vehicular communication has emerged. The objective of this work is to check feasibility of using infrastructure based vehicular communication for detecting and avoiding traffic congestion. In this paper we propose a Signal Agent (SA and Car Agent(CAbased approach for detecting and avoiding traffic congestion. We analyze performance of the proposed approach for two different road network scenarios using simulations: structured grid network (like Gandhinagar City of Gujarat, India and apart of typical city road network ( Tiwan city. With the proposed approach we get reduction of 10.05% in trip duration of vehicles, reduction of 10.08% in number of vehicles in entire traffic road network and 9.82% in heavy traffic area. In an accident scenario, about 72.63% vehicles changed their route due to awareness of congestion. Error in trip time estimation and vehicle count estimation is observed to be less than 1%.

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

Science.gov (United States)

2010-04-01

... 23 Highways 1 2010-04-01 2010-04-01 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...

Managing truck arrivals with time windows to alleviate gate congestion at container terminals

DEFF Research Database (Denmark)

Chen, G.; Govindan, Kannan; Yang, Z.

2013-01-01

Long truck queues at gates often limit the efficiency of a container terminal and generate serious air pollution. To reduce the gate congestion, this paper proposes a method called'vessel dependent time windows (VDTWs)' to control truck arrivals, which involves partitioning truck entries into gro......Long truck queues at gates often limit the efficiency of a container terminal and generate serious air pollution. To reduce the gate congestion, this paper proposes a method called'vessel dependent time windows (VDTWs)' to control truck arrivals, which involves partitioning truck entries...... into groups and assigning different time windows to the groups. The proposed VDTWs method includes three steps: (1) predicting truck arrivals based on the time window assignment, (2) estimating the queue length of trucks, and (3) optimizing the arrangement of time windows to minimize the total cost...

Visibility graph analysis of heart rate time series and bio-marker of congestive heart failure

Science.gov (United States)

Bhaduri, Anirban; Bhaduri, Susmita; Ghosh, Dipak

2017-09-01

Study of RR interval time series for Congestive Heart Failure had been an area of study with different methods including non-linear methods. In this article the cardiac dynamics of heart beat are explored in the light of complex network analysis, viz. visibility graph method. Heart beat (RR Interval) time series data taken from Physionet database [46, 47] belonging to two groups of subjects, diseased (congestive heart failure) (29 in number) and normal (54 in number) are analyzed with the technique. The overall results show that a quantitative parameter can significantly differentiate between the diseased subjects and the normal subjects as well as different stages of the disease. Further, the data when split into periods of around 1 hour each and analyzed separately, also shows the same consistent differences. This quantitative parameter obtained using the visibility graph analysis thereby can be used as a potential bio-marker as well as a subsequent alarm generation mechanism for predicting the onset of Congestive Heart Failure.

Transmission Congestion Management using a Wind Integrated Compressed Air Energy Storage System

Directory of Open Access Journals (Sweden)

S. Gope

2017-08-01

Full Text Available Transmission congestion is a vital problem in the power system security and reliability sector. To ensure the stable operation of the system, a congestion free power network is desirable. In this paper, a new Congestion Management (CM technique, the Wind integrated Compressed Air Energy Storage (WCAES system is used to alleviate transmission congestion and to minimize congestion mitigation cost. The CM problem has been solved by using the Generator Sensitivity Factor (GSF and the Bus Sensitivity Factor (BSF. BSF is used for finding the optimal location of WCAES in the system. GSF with a Moth Flame Optimization (MFO algorithm is used for rescheduling the generators to alleviate congestion and to minimize congestion cost by improving security margin. The impact of the WCAES system is tested with a 39 bus system. To validate this approach, the same problem has been solved with a Particle Swarm Optimization (PSO algorithm and the obtained results are compared with the ones from the MFO algorithm.

Research on Urban Road Congestion Pricing Strategy Considering Carbon Dioxide Emissions

Directory of Open Access Journals (Sweden)

Yitian Wang

2015-08-01

Full Text Available Congestion pricing strategy has been recognized as an effective countermeasure in the practical field of urban traffic congestion mitigation. In this paper, a bi-level programming model considering carbon dioxide emission is proposed to mitigate traffic congestion and reduce carbon dioxide emissions. The objective function of the upper level model is to minimize the sum of travel costs and the carbon dioxide emissions costs. The lower level is a multi-modal transportation network equilibrium model. To solve the model, the method of successive averages (MSA and the shuffled frog leaping algorithm (SFLA are introduced. The proposed method and algorithm are tested through the numerical example. The results show that the proposed congestion pricing strategy can mitigate traffic congestion and reduce carbon emissions effectively.

Indirect Damage of Urban Flooding: Investigation of Flood-Induced Traffic Congestion Using Dynamic Modeling

Directory of Open Access Journals (Sweden)

Jingxuan Zhu

2018-05-01

Full Text Available In many countries, industrialization has led to rapid urbanization. Increased frequency of urban flooding is one consequence of the expansion of urban areas which can seriously affect the productivity and livelihoods of urban residents. Therefore, it is of vital importance to study the effects of rainfall and urban flooding on traffic congestion and driver behavior. In this study, a comprehensive method to analyze the influence of urban flooding on traffic congestion was developed. First, a flood simulation was conducted to predict the spatiotemporal distribution of flooding based on Storm Water Management Model (SWMM and TELAMAC-2D. Second, an agent-based model (ABM was used to simulate driver behavior during a period of urban flooding, and a car-following model was established. Finally, in order to study the mechanisms behind how urban flooding affects traffic congestion, the impact of flooding on urban traffic was investigated based on a case study of the urban area of Lishui, China, covering an area of 4.4 km2. It was found that for most events, two-hour rainfall has a certain impact on traffic congestion over a five-hour period, with the greatest impact during the hour following the cessation of the rain. Furthermore, the effects of rainfall with 10- and 20-year return periods were found to be similar and small, whereas the effects with a 50-year return period were obvious. Based on a combined analysis of hydrology and transportation, the proposed methods and conclusions could help to reduce traffic congestion during flood seasons, to facilitate early warning and risk management of urban flooding, and to assist users in making informed decisions regarding travel.

Congestion Quantification Using the National Performance Management Research Data Set

Directory of Open Access Journals (Sweden)

Virginia P. Sisiopiku

2017-11-01

Full Text Available Monitoring of transportation system performance is a key element of any transportation operation and planning strategy. Estimation of dependable performance measures relies on analysis of large amounts of traffic data, which are often expensive and difficult to gather. National databases can assist in this regard, but challenges still remain with respect to data management, accuracy, storage, and use for performance monitoring. In an effort to address such challenges, this paper showcases a process that utilizes the National Performance Management Research Data Set (NPMRDS for generating performance measures for congestion monitoring applications in the Birmingham region. The capabilities of the relational database management system (RDBMS are employed to manage the large amounts of NPMRDS data. Powerful visual maps are developed using GIS software and used to illustrate congestion location, extent and severity. Travel time reliability indices are calculated and utilized to quantify congestion, and congestion intensity measures are developed and employed to rank and prioritize congested segments in the study area. The process for managing and using big traffic data described in the Birmingham case study is a great example that can be replicated by small and mid-size Metropolitan Planning Organizations to generate performance-based measures and monitor congestion in their jurisdictions.

Identifying the Onset of Congestion Rapidly with Existing Traffic Detectors

OpenAIRE

Coifman, Benjamin

1999-01-01

From an operations standpoint, the most important task of a traffic surveillance system is determining reliably whether the facility is free flowing or congested. The second most important task is responding rapidly when the facility becomes congested. Other tasks, such as quantifying the magnitude of congestion, are desirable, but tertiary. To address the first two tasks, this paper presents a new approach for traffic surveillance using existing detectors. Rather than expending a considerabl...

Developing Policy for Urban Autonomous Vehicles: Impact on Congestion

Directory of Open Access Journals (Sweden)

David Metz

2018-04-01

Full Text Available An important problem for surface transport is road traffic congestion, which is ubiquitous and difficult to mitigate. Accordingly, a question for policymakers is the possible impact on congestion of autonomous vehicles. It seems likely that the main impact of vehicle automation will not be seen until driverless vehicles are sufficiently safe for use amid general traffic on urban streets. Shared use driverless vehicles could reduce the cost of taxis and a wider range of public transport vehicles could be economic. Individually owned autonomous vehicles would have the ability to travel unoccupied and may need to be regulated where this might add to congestion. It is possible that autonomous vehicles could provide mobility services at lower cost and wider scope, such that private car use in urban areas could decline and congestion reduce. City authorities should be alert to these possibilities in developing transport policy.

Desk Congest Desktop Congesting Software for Desktop Clutter Congestion

Directory of Open Access Journals (Sweden)

Solomon A. Adepoju

2015-06-01

Full Text Available Abstract The computer desktop environment is a working environment which can be likened unto a users desk in homes and offices. Often times the computer desktop get cluttered with files either as shortcuts used for quick links files stored temporarily to be accessed later or just being dumped there for no vivid reasons. However previous researches have shown that cluttered desktop affects users productivity and getting these files organized is a laborious task for most users. To be able to conveniently alleviate the effect clutters have on users performances and productivity there is need for third party software that will help get the desktop environment organized in a logical and efficient manner. It is to this end that desktop decongesting software is being designed and implemented to help curb clutter problems which existing tools have only partially addressed. The system is designed using Visual Basic .Net and it proves to be effective in tackling desktop congestion problem.

Statewide planning scenario synthesis : transportation congestion measurement and management.

Science.gov (United States)

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...

Involvement of systemic venous congestion in heart failure.

Science.gov (United States)

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.

Mechanical analysis of congestive heart failure caused by bundle branch block based on an electromechanical canine heart model

Energy Technology Data Exchange (ETDEWEB)

Dou Jianhong; Xia Ling; Zhang Yu; Shou Guofa [Department of Biomedical Engineering, Zhejiang University, Hangzhou 310027 (China); Wei Qing; Liu Feng; Crozier, Stuart [School of Information Technology and Electrical Engineering, University of Queensland, St Lucia, Brisbane, Queensland 4072 (Australia)], E-mail: xialing@zju.edu.cn

2009-01-21

understanding of the mechanical implications of congestive heart failure (CHF) caused by BBB.

Congestion management enhancing transient stability of power systems

International Nuclear Information System (INIS)

Esmaili, Masoud; Shayanfar, Heidar Ali; Amjady, Nima

2010-01-01

In a competitive electricity market, where market parties try to maximize their profits, it is necessary to keep an acceptable level of power system security to retain the continuity of electricity services to customers at a reasonable cost. Congestion in a power system is turned up due to network limits. After relieving congestion, the network may be operated with a reduced transient stability margin because of increasing the contribution of risky participants. In this paper, a novel congestion management method based on a new transient stability criterion is introduced. Using the sensitivity of corrected transient stability margin with respect to generations and demands, the proposed method so alleviates the congestion that the network can more retain its transient security compared with earlier methods. The proposed transient stability index is constructed considering the likelihood of credible faults. Indeed, market parties participate by their security-effective bids rather than raw bids. Results of testing the proposed method along with the earlier ones on the New-England test system elaborate the efficiency of the proposed method from the viewpoint of providing a better transient stability margin with a lower security cost. (author)

How Smog Awareness Influences Public Acceptance of Congestion Charge Policies

Directory of Open Access Journals (Sweden)

Lingyi Zhou

2017-09-01

Full Text Available Although various studies have investigated public acceptance of congestion charge policies, most of them have focused on behavioral and policy-related factors, and did not consider the moderating influence that individual concern about smog and perceived smog risk may have on public acceptance. This paper takes the congestion charge policy in China, targeted at smog and traffic control, and checks how smog awareness—including smog concerns and perceived smog risks, besides behavioral and policy-related factors—might influence public acceptance of the policy. In this paper, we found both a direct and moderating causal relationship between smog awareness and public acceptance. Based on a sample of 574 valid questionnaires in Beijing and Shanghai in 2016, an ordered logistic regression modeling approach was used to delineate the causality between smog awareness and public acceptance. We found that both smog concerns, such as perceived smog risk, and willingness to pay (WTP were both directly and indirectly positively correlated with public acceptance. These findings imply that policymakers should increase policy fairness with environmental-oriented policy design and should express potential policy effectiveness of the smog controlling policy to citizens to increase their acceptance level.

Angiotensin-converting enzyme inhibition improves cardiac fatty acid metabolism in patients with congestive heart failure.

Science.gov (United States)

Yamauchi, S; Takeishi, Y; Minamihaba, O; Arimoto, T; Hirono, O; Takahashi, H; Miyamoto, T; Nitobe, J; Nozaki, N; Tachibana, H; Watanabe, T; Fukui, A; Kubota, I

2003-08-01

This study aimed to examine whether angiotensin-converting enzyme (ACE) inhibition improved cardiac fatty acid metabolism in patients with congestive heart failure (CHF). Myocardial 123I-beta-methyl-iodophenylpentadecanoic acid (123I-BMIPP) imaging was performed in 25 patients with CHF and in 10 control subjects. Myocardial 123I-BMIPP images were obtained 30 min and 4 h after tracer injection. The heart-to-mediastinum (H/M) ratio of 123I-BMIPP uptake and the washout rate of 123I-BMIPP from the myocardium were calculated. Patients were given enalapril for 6 months, and 123I-BMIPP imaging was repeated. H/M ratios on early and delayed images were lower in CHF patients than in normal controls (Pacid metabolism by ACE inhibition may represent a new mechanism for the beneficial effect of this therapy in heart failure.

Congestion Management System Process Report

Science.gov (United States)

1996-03-01

In January 1995, the Indianapolis Metropolitan Planning Organization with the help of an interagency Study Review Committee began the process of developing a Congestion Management System (CMS) Plan resulting in this report. This report documents the ...

Mathematical principles of road congestion pricing | Pienaar | ORiON

African Journals Online (AJOL)

This paper briefly considers the objectives of road congestion pricing and identies prereq-uisites to the successful application of such a pricing scheme. The paper is divided into two sections. In the rst section, a mathematical analysis of the constituents of an optimal road congestion price is oered. The eliminated inefficiency ...

Impact Analysis of Land Use on Traffic Congestion Using Real-Time Traffic and POI

Directory of Open Access Journals (Sweden)

Tianqi Zhang

2017-01-01

Full Text Available This paper proposed a new method to describe, compare, and classify the traffic congestion points in Beijing, China, by using the online map data and further revealed the relationship between traffic congestion and land use. The data of the point of interest (POI and the real-time traffic was extracted from an electronic map of the area in the fourth ring road of Beijing. The POIs were quantified based on the architectural area of the land use; the congestion points were identified based on real-time traffic. Then, the cluster analysis using the attributes of congestion time was conducted to identify the main traffic congestion areas. The result of a linear regression analysis between the congestion time and the land use showed that the influence of the high proportion of commercial land use on the traffic congestion was significant. Also, we considered five types of land use through performing a linear regression analysis between the congestion time and the ratio of four types of land use. The results showed that the reasonable ratio of land use types could efficiently reduce congestion time. This study makes contributions to the policy-making of urban land use.

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

Science.gov (United States)

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 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.

An efficient statistical-based approach for road traffic congestion monitoring

KAUST Repository

Abdelhafid, Zeroual

2017-12-14

In this paper, we propose an effective approach which has to detect traffic congestion. The detection strategy is based on the combinational use of piecewise switched linear traffic (PWSL) model with exponentially-weighted moving average (EWMA) chart. PWSL model describes traffic flow dynamics. Then, PWSL residuals are used as the input of EWMA chart to detect traffic congestions. The evaluation results of the developed approach using data from a portion of the I210-W highway in Califorina showed the efficiency of the PWSL-EWMA approach in in detecting traffic congestions.

An efficient statistical-based approach for road traffic congestion monitoring

KAUST Repository

Abdelhafid, Zeroual; Harrou, Fouzi; Sun, Ying

2017-01-01

In this paper, we propose an effective approach which has to detect traffic congestion. The detection strategy is based on the combinational use of piecewise switched linear traffic (PWSL) model with exponentially-weighted moving average (EWMA) chart. PWSL model describes traffic flow dynamics. Then, PWSL residuals are used as the input of EWMA chart to detect traffic congestions. The evaluation results of the developed approach using data from a portion of the I210-W highway in Califorina showed the efficiency of the PWSL-EWMA approach in in detecting traffic congestions.

Impact of multilateral congestion management on the reliability of power transactions

International Nuclear Information System (INIS)

Rodrigues, A.B.; Da Silva, M.G.

2003-01-01

The restructuring of the electricity industry has caused an increase in the number of transactions in the energy market. These transactions are defined by market forces without considering operational constraints of the transmission system. Consequently, there are transactions that cause congestion in the transmission network. This paper has as objective to assess the impact of multilateral congestion management on the reliability of power transactions. This assessment is based on reliability indices such as expected power curtailments, curtailment probability, expected cost of congestion management and probability distributions of the total power curtailment. Tests results with IEEE RTS-1996 demonstrate that the multilateral management results in smaller curtailments and congestion costs than traditional bilateral management. (author)

Give or take? Rewards versus charges for a congested bottleneck

NARCIS (Netherlands)

Rouwendal, J.; Verhoef, E.T.; Knockaert, J.

2012-01-01

This paper analyzes the possibilities to relieve traffic congestion using subsidies instead of Pigouvian taxes, as well as revenue-neutral combinations of rewards and taxes ('feebates'). The model considers a Vickrey-ADL model of bottleneck congestion with endogenous scheduling. With inelastic

Transmission dispatch and congestion management in open market systems

Science.gov (United States)

Fang, Risheng

This thesis is located in the domain of electricity supply industry restructuring. It deals with emerging issues, whose understanding is essential to advancing knowledge of open access transmission theory and proceeds to develop approaches for solving the transmission dispatch and congestion management problem. An overview of current trends and experiences in utility restructuring and the main models for restructuring, as well as the classifications of system operators, is first presented. A fully unbundled competitive electricity market model, called the bilateral/multilateral trades model, is then developed. A survey of current research in transmission dispatch and congestion management is included with discussion of transmission capacity and ancillary services. A methodology for the power dispatch problem in a structure dominated by bilateral and multilateral transmission contracts is presented. Group structures are mathematically formulated and explored and three basic types of curtailment strategies proposed for use by market participants. A more complex model is then developed, which takes into account the co-existence of bilateral and multilateral contracts with pool type dynamic supplies and demands based on bids and market clearing prices. An integrated dispatch strategy to reconcile all three types of transactions (bilateral, multilateral and pool) is then developed. Prioritization of electricity transactions and related curtailment strategies are explored and a mechanism for coordination between market participants to achieve additional economic advantages is described. A theory of security based rescheduling is presented in order to investigate the security-related aspects of operation in an unbundled and deregulated system. The impact of post-contingency corrective capability on optimal rescheduling results has been identified and the advantage of incorporating post-contingency corrective rescheduling into the objective function demonstrated. Finally

Congestion management in Alberta

International Nuclear Information System (INIS)

Way, R.

2002-01-01

The challenges facing Alberta regarding electricity market design and congestion management were described. The electricity market in the province consists of a central power pool, an open access transmission network, and a single pool price, unlike many other jurisdictions in North America which have adopted a location margin price (LMP) design with significant price differences between various locations within the power network. Alberta's transmission network is regulated and provides carrier functions. Power moves freely throughout Alberta's power pool network with no congestion, therefore the common pool price signals market participants throughout the entire network with no segregation into zones. Alberta is currently at a cross road in choosing between a single pool price model or a nodal price model. In the first instance, the province would have to strengthen the transmission network to maintain the market at a reasonable size. The alternative would permit Alberta to use market-based techniques to deal with the evolution of many smaller markets in the province, but these would be very small by North American standards and their ability to compete would be questionable

Backpressure-based control protocols: design and computational aspects

NARCIS (Netherlands)

Miretskiy, D.I.; Scheinhardt, Willem R.W.; Mandjes, M.R.H.

2009-01-01

Congestion control in packet-based networks is often realized by feedback protocols. In this paper we assess their performance under a back-pressure mechanism that has been proposed and standardized for Ethernet metropolitan networks. In such a mechanism the service rate of an upstream queue is

Backpressure-based control protocols: Design and computational aspects

NARCIS (Netherlands)

Miretskiy, D.I.; Scheinhardt, W.R.W.; Mandjes, M.R.H.

2009-01-01

Congestion control in packet-based networks is often realized by feedback protocols. In this paper we assess their performance under a back-pressure mechanism that has been proposed and standardized for Ethernet metropolitan networks. In such a mechanism the service rate of an upstream queue is

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

Science.gov (United States)

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.

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

Science.gov (United States)

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.

CONGESTIVE HEART FAILURE IN DOGS IS ASSOCIATED WITH INCREASED PLATELET LEUKOCYTE AGGREGATION MEASURED BY FLOW CYTOMETRY

DEFF Research Database (Denmark)

Tarnow, Inge; Andreasen, Susanne SH; Olsen, Lisbeth Høier

2010-01-01

Sciences, Faculty of Life Science, University of Copenhagen, Denmark. Chronic congestive heart failure (CHF) in humans is associated with abnormal hemostasis, and changes in hemostatic biomarkers carry a poor prognosis. CHF in dogs has been associated with plasma markers of hypercoagulability, however......CONGESTIVE HEART FAILURE IN DOGS IS ASSOCIATED WITH ENHANCED PLATELET-LEUKOCYTE AGGREGATES - A MARKER FOR PLATELET ACTIVATION. I Tarnow1, LH Olsen2, SHS Andreasen2, SG Moesgaard2, CE Rasmussen2, AT Kristensen1, T Falk2. 1Departments of Small Animal Clinical Sciences and 2Animal and Veterinary Basic......, platelet activation markers have not been investigated in dogs with clinical signs of heart disease. We hypothesized that platelet surface activation markers are higher in dogs with CHF compared to age-matched controls without clinical signs of heart failure. Dogs with compensated congestive heart failure...

Phantom Tumor of the Lung: Localized Interlobar Effusion in Congestive Heart Failure

Directory of Open Access Journals (Sweden)

Mislav Lozo

2014-01-01

Full Text Available Localized interlobar effusions in congestive heart failure (phantom or vanishing lung tumor/s is/are uncommon but well known entities. An 83-year-old man presented with shortness of breath, swollen legs, and dry cough enduring five days. Chest-X-ray (CXR revealed massive sharply demarked round/oval homogeneous dense shadow 10 × 7 cm in size in the right inferior lobe. The treatment with the loop diuretics and fluid intake reduction resulted in complete resolution of the observed round/oval tumor-like image on the control CXR three days later. Radiologic appearance of such a mass-like configuration in patients with congestive heart failure demands correction of the underlying heart condition before further diagnostic investigation is performed to avoid unnecessary, expensive, and possibly harmful diagnostic and treatment errors.

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

Directory of Open Access Journals (Sweden)

Rodolfo I Meneguette

Full Text Available 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.

Nordic congestion's arrangement as a model for Europe? Physical constraints vs. economic incentives

International Nuclear Information System (INIS)

Glachant, J.-M.; Pignon, V.

2005-01-01

Congestion on power grids seems a physical reality, a 'hard' fact easy to check. Our paper models a different idea: congestion signal may be distorted by transmission system operators (TSOs). Indeed, congestion signals are not physical data but 'home made' conventions directly set by the TSOs in charge of the security of the system. These security norms are not stable and invariable because lines capacity limits are not constant. TSOs, therefore, define the congestion signal on a variable, complex and non-transparent constraint and may manipulate it for monetary purposes or for other personal agenda. In Nordic countries the coexistence of two congestion management methods in a 'Light Handed Regulation' framework makes this opportunistic behaviour even more likely. (author)

Public Capital, Congestion and Private Production in Australia

OpenAIRE

Lei Lei Song

2002-01-01

This paper is an empirical investigation into the impact of public capital on the private sector’s economic activity in Australia. In particular, it is assumed that the contribution of public capital to private factor productivity is subject to congestion. New data sets of capital stocks and private output are constructed for the Australian economy. By estimating flexible functional forms of private sector production functions with congestion in public capital services, the paper shows that p...

Estimation of pulmonary water distribution and pulmonary congestion by computed tomography

International Nuclear Information System (INIS)

Morooka, Nobuhiro; Watanabe, Shigeru; Masuda, Yoshiaki; Inagaki, Yoshiaki

1982-01-01

Computed tomography (CT) of the lung in normal subjects and patients with congestive heart failure was performed in the supine position with deep inspiration to obtain pulmonary CT values and images. The mean CT value in normal subjects was higher in the posterior than anterior lung field, presumably because blood vessels were more dilated in the former than the latter due to the effects of gravity. The mean pulmonary CT value in patients with congestive heart failure was significantly increased possibly due to an increase in blood flow per unit lung volume arising from either pulmonary congestion or pulmonary interstitial and alveolar edema. The mean pulmonary CT value increased parallel to the severity of pulmonary congestion, interstitial or alveolar edema and was well correlated with the pulmonary arterial wedge pressure, indicating that such a correlation was a valuable tool in assessing therapeutic effects. The results of the present study indicatethat pulmonary CT is useful for the noninvasive estimation of intrapulmonary water content and its distribution, thereby providing an effective diagnostic clue to various conditions in congestive heart failure. (author)

Large-scale transportation network congestion evolution prediction using deep learning theory.

Science.gov (United States)

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.

Management of congestive heart failure (CHF): a case report on ...

African Journals Online (AJOL)

A case report on the management of Congestive Heart Failure is presented with emphasis on the use of DIGOXIN. Keywords: Congestive heart failure, Failing heart syndrome, Digoxin, Digoxin Toxicity. Full Text: EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT.

Renewable energy location and network congestion in a liberalised power market

International Nuclear Information System (INIS)

Singh, Balbir

2003-01-01

The report is a partial study in the SNF projects No. 3080 and 3155, ''Environmental measures and efficiency'' and ''Robust energy markets''. The study presents a spatial equilibrium optimisation model of a power market. The reports concludes that the economic and environmental efficiency of the introduction of renewable energy generation in a congested network is crucially dependent on the location of these resources in relation to the capacity constraints in the network. Physical laws that govern flows in meshed electricity networks introduce important substitution and complementary impacts between generation assets at various locations. Neglect of substitution impacts in location decisions may result in crowding-out of existing generation capacity during times of congestion, while on the other hand complementary relationships between new and existing generation may reduce congestion. In the context of introduction of new renewable technologies, there is need for coordination between the development of renewable generation resources and network capacity to avoid that crowding-out of existing capacity, particularly if the existing capacity is primarily hydropower. This would result in production and environmental inefficiency in policy implementation. It may be emphasized that coordination does not necessarily imply centralization of renewable energy and network developments. The research and policy challenge is to devise grid-access regime and tariff mechanism that promote the necessary coordination. In the Norwegian policy context, it calls for a flexibility for Statnett to determine appropriate access regime for the renewable energy and a greater advisory role in the licensing process undertaken by the Norwegian Water Resources and Energy Directorate (NVE)

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

Science.gov (United States)

2010-04-01

... 23 Highways 1 2010-04-01 2010-04-01 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...

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

Science.gov (United States)

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.

Large-scale transportation network congestion evolution prediction using deep learning theory.

Directory of Open Access Journals (Sweden)

Xiaolei Ma

Full Text Available 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.

Real-Time Congestion Management in Distribution Networks by Flexible Demand Swap

DEFF Research Database (Denmark)

Huang, Shaojun; Wu, Qiuwei

2017-01-01

In addition to the day-ahead congestion management in distribution networks, the real-time congestion management is very important because many unforeseen events can occur at the real operation time, e.g. loss of generation of distributed energy resources (DERs) or inaccurate forecast of energy...... pumps (HPs) for real time congestion management. The swap method can maintain the power balance of the system and avoid the imbalance cost of activating the flexibility service. An algorithm for forming swaps through optimal power flow (OPF) and mixed integer linear programming (MILP) is proposed...... consumption or production. Flexibility service from demand will be a good option to solve the real-time congestions if the cost of activating the flexibility service is fully addressed. This paper proposes a new method, namely “swap”, to employ the flexibility service from electric vehicles (EVs) and heat...

Congestion management of distribution networks with day-ahead dynamic grid tariffs

DEFF Research Database (Denmark)

Huang, Shaojun; Wu, Qiuwei

vehicles (EV) and heat pumps (HP), will be largely deployed in electrical distribution networks. Congestion management will be important in the future active distribution networks. In the IDE4L project, work package 5 is dedicated to develop different kinds of congestion management methods. Demand response...... (DR) is one of the important methods. In this report, as one task of work package 5, the day-ahead dynamic tariff (DADT) method for congestion management in distribution networks is presented. The dynamic tariff (DT) can motivate the flexible demands (EV and HP) to shift their energy consumption...

[Congestive cardiomyopathy in addiction to clobenzorex, an anorexigenic drug].

Science.gov (United States)

Cornaert, P; Camblin, J; Graux, P; Anaye, B; Dutoit, A; Croccel, L

1986-04-01

Cardiac failure caused by high doses of amphetamine-like drugs is rare. We report a case of decompensated congestive cardiomyopathy occurring in a 29 year old woman addicted to clobenzorex (Dinintel). This patient had been taking 5 to 7 capsules per day for 5 years. No other cause of cardiac failure was detected. A rapid improvement was obtained by digitalis and diuretic therapy; no further episodes of cardiac failure were observed after one year. However, the drug could not be completely withdrawn and echocardiography has shown increasing left ventricular dilatation. The possible mechanisms of amphetamine induced myocardial toxicity are discussed and the analogy with the group of adrenergic cardiomyopathies is underlined.

Framework for Traffic Congestion Prediction

NARCIS (Netherlands)

Zaki, J.F.W.; Ali-Eldin, A.M.T.; Hussein, S.E.; Saraya, S.F.; Areed, F.F.

2016-01-01

Traffic Congestion is a complex dilemma facing most major cities. It has undergone a lot of research since the early 80s in an attempt to predict traffic in the short-term. Recently, Intelligent Transportation Systems (ITS) became an integral part of traffic research which helped in modeling and

Modeling truck traffic volume growth congestion.

Science.gov (United States)

2009-05-01

Modeling of the statewide transportation system is an important element in understanding issues and programming of funds to thwart potential congestion. As Alabama grows its manufacturing economy, the number of heavy vehicles traversing its highways ...

Study and Analysis of Congestion Management in Hybrid Electric Market

Directory of Open Access Journals (Sweden)

Moayed Mohseni

2013-01-01

Full Text Available The congestion management system is a systematic approach, collaboratively developed and implemented throughout a metropolitan region that provides for the safe and effective management and operation of new and existing transportation facilities through the use of demand reduction and operational management strat­e­gies. In this paper we try to present some points which should be investigated in congestion management problems. We calculate different kinds of congestion problems which may be occurred in our network. Here, the hybrid model is used to solve problems in the electricity market to solve the congestion problem in the network and Benders techniques is used together with an optimal power flow (OPF. In fact, by using of Benders algorithm the problem is divided into two major and minor problems. Therefore, the major problem related to the economy sector and no network is included and the minor problem is to solve the network and examine the accuracy of the network. Benders algorithm has been tested on a standard network IEEE 24 bus and Matlab software is used to implement the algorithm.

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

International Nuclear Information System (INIS)

Glowniak, J.V.; Turner, F.E.; Gray, L.L.; Palac, R.T.; Lagunas-Solar, M.C.; Woodward, W.R.

1989-01-01

Iodine-123 metaiodobenzylguanidine ([ 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 [ 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 cardiac 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

Day-ahead tariffs for the alleviation of distribution grid congestion from electric vehicles

DEFF Research Database (Denmark)

O'Connell, Niamh; Wu, Qiuwei; Østergaard, Jacob

2012-01-01

An economically efficient day-ahead tariff (DT) is proposed with the purpose of preventing the distribution grid congestion resulting from electric vehicle (EV) charging scheduled on a dayahead basis. The DT concept developed herein is derived from the locational marginal price (LMP), in particular...... the congestion cost component of the LMP. A step-wise congestion management structure has been developed whereby the distribution system operator (DSO) predicts congestion for the coming day and publishes DTs prior to the clearing of the day-ahead market. EV fleet operators (FOs) optimize their EV charging...... schedules with respect to the predicted day-ahead prices and the published DTs, thereby avoiding congestion while still minimizing the charging cost. A Danish 400V distribution network is used to carry out case studies to illustrate the effectiveness of the developed concept for the prevention...

Directional Congestion and Regime Switching in a Long Memory Model for Electricity Prices

DEFF Research Database (Denmark)

Haldrup, Niels; Nielsen, Morten Ø.

The functioning of electricity markets has experienced increasing complexityas a result of deregulation in recent years. Consequently this affects the multilateral price behaviour across regions with physical exchange of power. It has been documented elsewhere that features such aslong memory...... and regime switching reflecting congestion and non-congestion periods are empirically relevant and hence are features that need to be taken into account when modeling price behavior. In the present paper we further elaborate on the co-existence of long memory and regime switches by focusing on the effect...... that the direction of possible congestion episodes has on the price dynamics. Under non-congestion prices are identical. The direction of possible congestion is identified by the region with excess demand of power through the sign of price differences and hence three different states can be considered: Non...

Vehicle Routing with Traffic Congestion and Drivers' Driving and Working Rules

NARCIS (Netherlands)

Kok, A.L.; Hans, Elias W.; Schutten, Johannes M.J.; Zijm, Willem H.M.

2010-01-01

For the intensively studied vehicle routing problem (VRP), two real-life restrictions have received only minor attention in the VRP-literature: traffic congestion and driving hours regulations. Traffic congestion causes late arrivals at customers and long travel times resulting in large transport

Control and Optimization of Network in Networked Control System

Directory of Open Access Journals (Sweden)

Wang Zhiwen

2014-01-01

Full Text Available In order to avoid quality of performance (QoP degradation resulting from quality of service (QoS, the solution to network congestion from the point of control theory, which marks departure of our results from the existing methods, is proposed in this paper. The congestion and bandwidth are regarded as state and control variables, respectively; then, the linear time-invariant (LTI model between congestion state and bandwidth of network is established. Consequently, linear quadratic method is used to eliminate the network congestion by allocating bandwidth dynamically. At last, numerical simulation results are given to illustrate the effectiveness of this modeling approach.

Expanding the Scope of Sustainability Planning: Lessons from Stockholm’s Congestion Charging Policy

Directory of Open Access Journals (Sweden)

Amy Rader Olsson

2017-10-01

Full Text Available In 2007, after years of unresolved debate, the Swedish parliament approved a congestion charge for Stockholm applied to cars crossing the city’s inner boundary. Since its introduction, congestion charging has led to an even more lasting reduction of car trips to the city center, in part because the policy generates revenues for financing new subway extensions and uses these same resources as the basis for negotiating new transit oriented housing in subway extension areas. As such, congestion charging is arguably as much a sustainable housing solution as it is a narrowly defined transit policy for reducing automobile congestion or pollution. This article investigates how and why Stockholm, despite considerable political conflict, technical complexity and negative public opinion, was able to turn a long-standing and controversial debate over moderating automobile traffic via tolls into widespread support for a national congestion tax, which itself laid the groundwork for a more expansive sustainability agenda. It further suggests that only when congestion charging was strategically reframed and widely recognized as addressing the concerns of multiple and competing constituencies, did efforts for its adoption translate into larger sustainability gains.

Transit Station Congestion Index Research Based on Pedestrian Simulation and Gray Clustering Evaluation

Directory of Open Access Journals (Sweden)

Shu-wei Wang

2013-01-01

Full Text Available A congestion phenomenon in a transit station could lead to low transfer efficiency as well as a hidden danger. Effective management of congestion phenomenon shall help to reduce the efficiency decline and danger risk. However, due to the difficulty in acquiring microcosmic pedestrian density, existing researches lack quantitative indicators to reflect congestion degree. This paper aims to solve this problem. Firstly, platform, stair, transfer tunnel, auto fare collection (AFC machine, and security check machine were chosen as key traffic facilities through large amounts of field investigation. Key facilities could be used to reflect the passenger density of a whole station. Secondly, the pedestrian density change law of each key traffic facility was analyzed using pedestrian simulation, and the load degree calculating method of each facility was defined, respectively, afterwards. Taking pedestrian density as basic data and gray clustering evaluation as algorithm, an index called Transit Station Congestion Index (TSCI was constructed to reflect the congestion degree of transit stations. Finally, an evaluation demonstration was carried out with five typical transit transfer stations in Beijing, and the evaluation results show that TSCI can objectively reflect the congestion degree of transit stations.

On the stability and multi-stability of a TCP/RED congestion control model with state-dependent delay and discontinuous marking function

Science.gov (United States)

Zhang, Shu; Xu, Jian; Chung, Kwok-wai

2015-05-01

Random early detection (RED) is an effective algorithm to control the Internet congestion. However, researches on RED parameters are difficult since there are state-dependent delay and discontinuous terms on the right-hand side of the model. We smooth the model by hyperbolic tangent function and reformulate it by a switch function to keep state variables positive. Numerical simulations on the original system validates the reformulated model. The multi-stability phenomenon is observed and some suggestions on the selection of RED parameters are given to enhance the global stability of the model by numerical bifurcation continuation on the reformulated model.

Mathematical principles of road congestion pricing

African Journals Online (AJOL)

route during the morning peak hour: cost and demand functions. the same at all traffic levels. Although car running costs rise with increases in travel time in congested urban travel conditions, they are usually regarded by road users as being.

Bottleneck congestion and distribution of work start times: The economics of staggered work hours revisited

OpenAIRE

Takayama, Yuki

2014-01-01

Since the seminal work of Henderson (1981), a number of studies examined the effect of staggered work hours by analyzing models of work start time choice that consider the trade-off between negative congestion externalities and positive production externalities. However, these studies described traffic congestion using flow congestion models. This study develops a model of work start time choice with bottleneck congestion and discloses the intrinsic properties of the model. To this end, this ...

Congestion and residential moving behaviour

DEFF Research Database (Denmark)

Larsen, Morten Marott; Pilegaard, Ninette; Van Ommeren, Jos

2008-01-01

to congestion. We focus on the equilibrium in which some workers currently living in one region accept jobs in the other, with a fraction of them choosing to commute from their current residence to the new job in the other region and the remainder choosing to move to the region in which the new job is located...

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

Science.gov (United States)

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.

Alleviate Cellular Congestion Through Opportunistic Trough Filling

Directory of Open Access Journals (Sweden)

Yichuan Wang

2014-04-01

Full Text Available The demand for cellular data service has been skyrocketing since the debut of data-intensive smart phones and touchpads. However, not all data are created equal. Many popular applications on mobile devices, such as email synchronization and social network updates, are delay tolerant. In addition, cellular load varies significantly in both large and small time scales. To alleviate network congestion and improve network performance, we present a set of opportunistic trough filling schemes that leverage the time-variation of network congestion and delay-tolerance of certain traffic in this paper. We consider average delay, deadline, and clearance time as the performance metrics. Simulation results show promising performance improvement over the standard schemes. The work shed lights on addressing the pressing issue of cellular overload.

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

Science.gov (United States)

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.

On the Inefficiency of Equilibria in Linear Bottleneck Congestion Games

Science.gov (United States)

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.

A novel symbiotic organisms search algorithm for congestion management in deregulated environment

Science.gov (United States)

Verma, Sumit; Saha, Subhodip; Mukherjee, V.

2017-01-01

In today's competitive electricity market, managing transmission congestion in deregulated power system has created challenges for independent system operators to operate the transmission lines reliably within the limits. This paper proposes a new meta-heuristic algorithm, called as symbiotic organisms search (SOS) algorithm, for congestion management (CM) problem in pool based electricity market by real power rescheduling of generators. Inspired by interactions among organisms in ecosystem, SOS algorithm is a recent population based algorithm which does not require any algorithm specific control parameters unlike other algorithms. Various security constraints such as load bus voltage and line loading are taken into account while dealing with the CM problem. In this paper, the proposed SOS algorithm is applied on modified IEEE 30- and 57-bus test power system for the solution of CM problem. The results, thus, obtained are compared to those reported in the recent state-of-the-art literature. The efficacy of the proposed SOS algorithm for obtaining the higher quality solution is also established.

COALA: A Protocol for the Avoidance and Alleviation of Congestion in Wireless Sensor Networks.

Science.gov (United States)

Kandris, Dionisis; Tselikis, George; Anastasiadis, Eleftherios; Panaousis, Emmanouil; Dagiuklas, Tasos

2017-10-31

The occurrence of congestion has an extremely deleterious impact on the performance of Wireless Sensor Networks (WSNs). This article presents a novel protocol, named COALA ( COngestion ALleviation and Avoidance ), which aims to act both proactively, in order to avoid the creation of congestion in WSNs, and reactively, so as to mitigate the diffusion of upcoming congestion through alternative path routing. Its operation is based on the utilization of an accumulative cost function, which considers both static and dynamic metrics in order to send data through the paths that are less probable to be congested. COALA is validated through simulation tests, which exhibit its ability to achieve remarkable reduction of loss ratios, transmission delays and energy dissipation. Moreover, the appropriate adjustment of the weighting of the accumulative cost function enables the algorithm to adapt to the performance criteria of individual case scenarios.

Traffic Congestion Detection System through Connected Vehicles and Big Data

OpenAIRE

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

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 ...

78 FR 67442 - Congestion Mitigation and Air Quality Improvement Program Interim Guidance

Science.gov (United States)

2013-11-12

...] Congestion Mitigation and Air Quality Improvement Program Interim Guidance AGENCY: Federal Highway... Comment. SUMMARY: The FHWA is issuing Interim Guidance on the Congestion Mitigation and Air Quality.../environment/air_quality/cmaq/policy_and_guidance/2008_guidance/ guidance/. DATES: This Interim Guidance is...

Grid Mapping for Spatial Pattern Analyses of Recurrent Urban Traffic Congestion Based on Taxi GPS Sensing Data

Directory of Open Access Journals (Sweden)

Yang Liu

2017-03-01

Full Text Available Traffic congestion is one of the most serious problems that impact urban transportation efficiency, especially in big cities. Identifying traffic congestion locations and occurring patterns is a prerequisite for urban transportation managers in order to take proper countermeasures for mitigating traffic congestion. In this study, the historical GPS sensing data of about 12,000 taxi floating cars in Beijing were used for pattern analyses of recurrent traffic congestion based on the grid mapping method. Through the use of ArcGIS software, 2D and 3D maps of the road network congestion were generated for traffic congestion pattern visualization. The study results showed that three types of traffic congestion patterns were identified, namely: point type, stemming from insufficient capacities at the nodes of the road network; line type, caused by high traffic demand or bottleneck issues in the road segments; and region type, resulting from multiple high-demand expressways merging and connecting to each other. The study illustrated that the proposed method would be effective for discovering traffic congestion locations and patterns and helpful for decision makers to take corresponding traffic engineering countermeasures in order to relieve the urban traffic congestion issues.

HOW TRAVEL DEMAND AFFECTS DETECTION OF NON-RECURRENT TRAFFIC CONGESTION ON URBAN ROAD NETWORKS

Directory of Open Access Journals (Sweden)

B. Anbaroglu

2016-06-01

Full Text Available 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.

COALA: A Protocol for the Avoidance and Alleviation of Congestion in Wireless Sensor Networks

Directory of Open Access Journals (Sweden)

Dionisis Kandris

2017-10-01

Full Text Available The occurrence of congestion has an extremely deleterious impact on the performance of Wireless Sensor Networks (WSNs. This article presents a novel protocol, named COALA (COngestion ALleviation and Avoidance, which aims to act both proactively, in order to avoid the creation of congestion in WSNs, and reactively, so as to mitigate the diffusion of upcoming congestion through alternative path routing. Its operation is based on the utilization of an accumulative cost function, which considers both static and dynamic metrics in order to send data through the paths that are less probable to be congested. COALA is validated through simulation tests, which exhibit its ability to achieve remarkable reduction of loss ratios, transmission delays and energy dissipation. Moreover, the appropriate adjustment of the weighting of the accumulative cost function enables the algorithm to adapt to the performance criteria of individual case scenarios.

Vehicle routing under time-dependent travel times: the impact of congestion avoidance

NARCIS (Netherlands)

Kok, A.L.; Hans, Elias W.; Schutten, Johannes M.J.

2009-01-01

Daily traffic congestions form major problems for businesses such as logistical service providers and distribution firms. They cause late arrivals at customers and additional hiring costs for the truck drivers. The additional costs of traffic congestions can be reduced by taking into account and

Effective use of congestion in complex networks

Science.gov (United States)

Echagüe, Juan; Cholvi, Vicent; Kowalski, Dariusz R.

2018-03-01

In this paper, we introduce a congestion-aware routing protocol that selects the paths according to the congestion of nodes in the network. The aim is twofold: on one hand, and in order to prevent the networks from collapsing, it provides a good tolerance to nodes' overloads; on the other hand, and in order to guarantee efficient communication, it also incentivize the routes to follow short paths. We analyze the performance of our proposed routing strategy by means of a series of experiments carried out by using simulations. We show that it provides a tolerance to collapse close to the optimal value. Furthermore, the average length of the paths behaves optimally up to the certain value of packet generation rate ρ and it grows in a linear fashion with the increase of ρ.

Can complexity decrease in congestive heart failure?

Science.gov (United States)

Mukherjee, Sayan; Palit, Sanjay Kumar; Banerjee, Santo; Ariffin, M. R. K.; Rondoni, Lamberto; Bhattacharya, D. K.

2015-12-01

The complexity of a signal can be measured by the Recurrence period density entropy (RPDE) from the reconstructed phase space. We have chosen a window based RPDE method for the classification of signals, as RPDE is an average entropic measure of the whole phase space. We have observed the changes in the complexity in cardiac signals of normal healthy person (NHP) and congestive heart failure patients (CHFP). The results show that the cardiac dynamics of a healthy subject is more complex and random compare to the same for a heart failure patient, whose dynamics is more deterministic. We have constructed a general threshold to distinguish the border line between a healthy and a congestive heart failure dynamics. The results may be useful for wide range for physiological and biomedical analysis.

Efficient determination of distribution tariffs for the prevention of congestion from EV Charging

DEFF Research Database (Denmark)

O'Connell, Niamh; Wu, Qiuwei; Østergaard, Jacob

2012-01-01

into the day-ahead market. The DT acts to disperse charging at congested periods and locations, thereby preventing congestion on a day-ahead basis. The magnitude of the DT is determined from a simulated locational marginal prices (LMPs), and the time extent of the DT is determined from analysis of the system...... loading curve prior to the application of the DT. Case studies were performed using a sample distribution network modelled on a network from the Danish island of Bornholm. A variety of price profiles were used to illustrate the efficacy of this approach. The case study results show that this approach...... is highly efficient at grid congestion prevention, and the precise level of congestion that can be alleviated is dependent on the price profile of the optimisation period in question....

Novel Congestion-Free Alternate Routing Path Scheme using Stackelberg Game Theory Model in Wireless Networks

Directory of Open Access Journals (Sweden)

P. Chitra

2017-04-01

Full Text Available Recently, wireless network technologies were designed for most of the applications. Congestion raised in the wireless network degrades the performance and reduces the throughput. Congestion-free network is quit essen- tial in the transport layer to prevent performance degradation in a wireless network. Game theory is a branch of applied mathematics and applied sciences that used in wireless network, political science, biology, computer science, philosophy and economics. e great challenges of wireless network are their congestion by various factors. E ective congestion-free alternate path routing is pretty essential to increase network performance. Stackelberg game theory model is currently employed as an e ective tool to design and formulate conges- tion issues in wireless networks. is work uses a Stackelberg game to design alternate path model to avoid congestion. In this game, leaders and followers are selected to select an alternate routing path. e correlated equilibrium is used in Stackelberg game for making better decision between non-cooperation and cooperation. Congestion was continuously monitored to increase the throughput in the network. Simulation results show that the proposed scheme could extensively improve the network performance by reducing congestion with the help of Stackelberg game and thereby enhance throughput.

Weighted congestion coefficient feedback in intelligent transportation systems

International Nuclear Information System (INIS)

Dong Chuanfei; Ma Xu; Wang Binghong

2010-01-01

In traffic systems, a reasonable information feedback can improve road capacity. In this Letter, we study dynamics of traffic flow with real-time information. And the influence of a feedback strategy named Weighted Congestion Coefficient Feedback Strategy (WCCFS) is introduced, based on a two-route scenario in which dynamic information can be generated and displayed on the board to guide road users to make a choice. Our model incorporates the effects of adaptability into the cellular automaton models of traffic flow and simulation results adopting this optimal information feedback strategy have demonstrated high efficiency in controlling spatial distribution of traffic patterns compared with the other three information feedback strategies, i.e., vehicle number and flux.

Transmission economic expansion and congestion relief : a case study

Energy Technology Data Exchange (ETDEWEB)

Chao, H.; Trinh, L.H.; Moore, M. [ABB Consulting, Raleigh, NC (United States); Brown, L.; Patel, K. [SDG and E, San Diego, CA (United States)

2006-07-01

Transmission capacity additions have lagged behind load growth and generation expansion in the United States. This paper provided an economic analysis of various transmission upgrade options designed to address anticipated congestion of the electricity grid. A market-based transmission planning method was used to assess the economics of transmission expansion. The analysis accounted for the minimum costs of generation dispatch to satisfy transmission constraints, as well as a locational marginal price for each bus in the system. Marginal congestion costs for all major transmission facilities were monitored and recorded. Hourly simulations of load, generation, and transmission system interactions were conducted. Contract costs and economic measures were then calculated for each scenario run. A case study for the Sunrise Powerlink project was used to demonstrate the efficacy of the method. The study demonstrated that the Sunrise Powerlink project will eliminate significant congestion in California load centers. Results also showed that the analytical method provided critical information for decision-makers in weighing the costs with benefits for transmission projects. 5 refs., 2 tabs., 1 fig.

Índice de congestão portal e a ocorrência de trombose portal pós-dape Portal congestion and thrombosis after EDS

Directory of Open Access Journals (Sweden)

Fabio Gonçalves Ferreira

2005-08-01

Full Text Available OBJETIVO: Comparar os dados obtidos pela ultra-sonografia com doppler no pré-operatório de esquistossomóticos submetidos à desconexão ázigo-portal com esplenectomia (DAPE, calculando o índice de congestão portal, e sua correlação com a trombose portal no pós-operatório. MÉTODOS: Foram estudados 65 pacientes submetidos à DAPE por hipertensão portal esquistossomótica com antecedente de hemorragia digestiva, divididos em dois grupos: Grupo A (28 pacientes que não desenvolveram trombose portal pós-operatória e Grupo B (37 pacientes com trombose portal no pós-operatório. Analisaram-se através de ultra-sonografia com doppler no pré-operatório os seguintes parâmetros da veia porta: diâmetro, área, velocidade média de fluxo do sangue, fluxo de sangue, e estabeleceu-se o índice de congestão portal. RESULTADOS: O diâmetro, área e o fluxo da veia porta foram maiores no grupo B (média de 1,52 cm; 1,77 cm² e 2533,12 ml/min em relação ao grupo A (média de 1,33 cm; 1,44 cm² e 1609,03 ml/min com p = 0,03; 0,03 e 0,04 respectivamente. O índice de congestão portal não foi estatisticamente significativo na comparação dos dois grupos (p = 0,07. CONCLUSÃO: O índice de congestão portal obtido no pré-operatório através da ultra-sonografia com doppler não se mostrou preditivo de trombose portal no pós-operatório dos doentes estudados.BACKGROUND: The study compared the preoperative portal vein congestion index estimated by Doppler ultrasound and the postoperative portal vein thrombosis of patients submitted to esophagogastric devascularization and splenectomy (EDS. METHODS: 65 patients with portal hypertension due to schistosomiasis and previous gastrointestinal bleeding submitted to EDS were divided into two groups: GROUP A (28 patients without postoperative portal vein thrombosis and GROUP B (37 patients with postoperative portal vein thrombosis. The following parameters of preoperative Doppler ultrasound of the

Hemostatic biomarkers in dogs with chronic congestive heart failure

DEFF Research Database (Denmark)

Tarnow, Inge; Falk, Torkel; Tidholm, Anna

2007-01-01

Background: Chronic congestive heart failure (CHF) in humans is associated with abnormal hemostasis, and abnormalities in hemostatic biomarkers carry a poor prognosis. Alterations in hemostatic pathways can be involved in the pathogenesis of CHF in dogs, and microthrombosis in the myocardium could...... contribute to increased mortality. Hypothesis: That plasma concentration or activity of hemostatic biomarkers is altered in dogs with CHF and that these factors predict mortality. Animals: Thirty-four dogs with CHF caused by either dilated cardiomyopathy (DCM, n = 14) or degenerative valvular disease (CDVD......, n = 20) compared with 23 healthy age-matched control dogs were included in this study. Dogs with CHF were recruited from 2 referral cardiology clinics, and control dogs were owned by friends or colleagues of the investigators. Methods: Clinical examination and echocardiography were performed in all...

Stochastic Stability in Internet Router Congestion Games

Science.gov (United States)

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.

Chance Constrained Input Relaxation to Congestion in Stochastic DEA. An Application to Iranian Hospitals.

Science.gov (United States)

Kheirollahi, Hooshang; Matin, Behzad Karami; Mahboubi, Mohammad; Alavijeh, Mehdi Mirzaei

2015-01-01

This article developed an approached model of congestion, based on relaxed combination of inputs, in stochastic data envelopment analysis (SDEA) with chance constrained programming approaches. Classic data envelopment analysis models with deterministic data have been used by many authors to identify congestion and estimate its levels; however, data envelopment analysis with stochastic data were rarely used to identify congestion. This article used chance constrained programming approaches to replace stochastic models with "deterministic equivalents". This substitution leads us to non-linear problems that should be solved. Finally, the proposed method based on relaxed combination of inputs was used to identify congestion input in six Iranian hospital with one input and two outputs in the period of 2009 to 2012.

Study on plasma levels of brain natriuretic peptide, angiotensin and aldosterone in patients with congestive heart failure

International Nuclear Information System (INIS)

Cheng Yu; Hong Liquan; Chen Zhaojun

2009-01-01

Objective: To investigate the relationship between brain natriuretic peptide (BNP), angiotensin (AT-II), and aldosterone (ALD) levels in patients with congestive heart failure (CHF). Methods: Plasma levels of BNP (with CLIA) and Angiotensin II (AT-II), aldosterone (ALD) (with RIA) were measured in 98 patients with CHF, 76 cardiac patients without heart faclure, and 86 controls. Results: The plasma levels of BNP, AT-II and ALD in patients (with RIA) CHF were significantly higher than those in the controls. The levels of BNP, AT-II and ALD, CHF patients after therapy were markedly dropped and were significantly lower than those patients before therapy (P<0.01). BNP levels were positively correlated with AT-II and ALD in levels CHF (P<0.05). Conclusion: The over activity of RAA systems may be one of the mechanisms of heart failure. Dynamic observation of changes of BNP, AT-II and ALD may be very useful in assessment of severity and prognosis of patients with CHF. (authors)

Application of economic models to estimate the acceptability of a vehicle congestion charge

Directory of Open Access Journals (Sweden)

José Carlos Jiménez Serpa

2017-07-01

Full Text Available Introduction: Through the study of the problems generated by vehicular traffic congestion during periods of maximum demand, the negative externality of congestion would be assessed using Multinomial Logit, Mixed and econometric models, and willingness to pay through a Pigouvian rate. Objective: In this article, we propose to implement a congestion charge to manage vehicular demand, through the application of declared preference gages and econometric models. Methodology: The study consists of the execution of 6 steps or stages: Background of the problem, Context of study, Methodological Foundations, Specification and estimation of the model, Estimation of the function average cost user and social marginal cost, Results obtained Discussion and report. Results: Analyzing the models obtained from the 2053 observations made through the declared preference surveys, it was observed that in order to discourage the use of the private car, a rate of COP 7000 per vehicle entering the congestion area or area should be charged, which would decrease the Use of Auto Particular in 68.7%, referring to this behavior we can say that the government policies that set the collection of the congestion charge is a policy that does not fit the perception of the users. Conclusions: This research identified the rate that reflects as closely as possible the marginal social cost and the generalized costs of each trip in terms of the impacts on the others. Now if we consider the marginal cost due to congestion, we have that the current demand is excessive, the users enjoy the benefit at a cost of $ 3,100COP, but impose to others a quota of $22,152COP. Finally, it is necessary to strengthen the legal basis with the regulation and creation of a National Vehicle Electronic Identification System, which will allow, in principle, charges for congestion.

On the Existence of Solutions for Stationary Mean-Field Games with Congestion

KAUST Repository

Evangelista, David; Gomes, Diogo A.

2017-01-01

Mean-field games (MFGs) are models of large populations of rational agents who seek to optimize an objective function that takes into account their location and the distribution of the remaining agents. Here, we consider stationary MFGs with congestion and prove the existence of stationary solutions. Because moving in congested areas is difficult, agents prefer to move in non-congested areas. As a consequence, the model becomes singular near the zero density. The existence of stationary solutions was previously obtained for MFGs with quadratic Hamiltonians thanks to a very particular identity. Here, we develop robust estimates that give the existence of a solution for general subquadratic Hamiltonians.

On the Existence of Solutions for Stationary Mean-Field Games with Congestion

KAUST Repository

Evangelista, David

2017-09-11

Mean-field games (MFGs) are models of large populations of rational agents who seek to optimize an objective function that takes into account their location and the distribution of the remaining agents. Here, we consider stationary MFGs with congestion and prove the existence of stationary solutions. Because moving in congested areas is difficult, agents prefer to move in non-congested areas. As a consequence, the model becomes singular near the zero density. The existence of stationary solutions was previously obtained for MFGs with quadratic Hamiltonians thanks to a very particular identity. Here, we develop robust estimates that give the existence of a solution for general subquadratic Hamiltonians.

Green Eco-Driving Effects in Non-Congested Cities

Directory of Open Access Journals (Sweden)

Juan Francisco Coloma

2017-12-01

Full Text Available Despite technological advances in engines and fuels, the transportation sector is still one of the largest emitters of greenhouse gas (GHG. Driving patterns, including eco-driving techniques, are a complementary measure for saving GHG emissions. Most eco-driving studies so far have been conducted in large cities suffering chronic congestion problems. The aim of this research is therefore to analyse the potential of driver behaviour for reducing emissions in a small non-congested city. Driver performance parameters such as travel speeds, number of stops, revolutions per minute, and maximum acceleration-deceleration are also studied. The methodology is designed to measure the effect of both eco-driving and eco-routing under real traffic conditions. A campaign was carried out in the city of Caceres (Spain to collect data on various types of roads under different traffic conditions. This research concludes that eco-driving leads to CO2 savings on all routes and road types of 17% in gasoline engines and 21% in diesel, although travel times are increased by 7.5% on average. The shortest route is also the most ecological, regardless of the traffic volume and characteristics, implying that consumption in non-congested cities depends mainly on distance travelled rather than driving patterns in terms of number of stops, speed and acceleration.

Congestion-Aware Warehouse Flow Analysis and Optimization

KAUST Repository

AlHalawani, Sawsan

2015-12-18

Generating realistic configurations of urban models is a vital part of the modeling process, especially if these models are used for evaluation and analysis. In this work, we address the problem of assigning objects to their storage locations inside a warehouse which has a great impact on the quality of operations within a warehouse. Existing storage policies aim to improve the efficiency by minimizing travel time or by classifying the items based on some features. We go beyond existing methods as we analyze warehouse layout network in an attempt to understand the factors that affect traffic within the warehouse. We use simulated annealing based sampling to assign items to their storage locations while reducing traffic congestion and enhancing the speed of order picking processes. The proposed method enables a range of applications including efficient storage assignment, warehouse reliability evaluation and traffic congestion estimation.

Congestion-Aware Warehouse Flow Analysis and Optimization

KAUST Repository

AlHalawani, Sawsan; Mitra, Niloy J.

2015-01-01

Generating realistic configurations of urban models is a vital part of the modeling process, especially if these models are used for evaluation and analysis. In this work, we address the problem of assigning objects to their storage locations inside a warehouse which has a great impact on the quality of operations within a warehouse. Existing storage policies aim to improve the efficiency by minimizing travel time or by classifying the items based on some features. We go beyond existing methods as we analyze warehouse layout network in an attempt to understand the factors that affect traffic within the warehouse. We use simulated annealing based sampling to assign items to their storage locations while reducing traffic congestion and enhancing the speed of order picking processes. The proposed method enables a range of applications including efficient storage assignment, warehouse reliability evaluation and traffic congestion estimation.

Error and Congestion Resilient Video Streaming over Broadband Wireless

Directory of Open Access Journals (Sweden)

Laith Al-Jobouri

2015-04-01

Full Text Available In this paper, error resilience is achieved by adaptive, application-layer rateless channel coding, which is used to protect H.264/Advanced Video Coding (AVC codec data-partitioned videos. A packetization strategy is an effective tool to control error rates and, in the paper, source-coded data partitioning serves to allocate smaller packets to more important compressed video data. The scheme for doing this is applied to real-time streaming across a broadband wireless link. The advantages of rateless code rate adaptivity are then demonstrated in the paper. Because the data partitions of a video slice are each assigned to different network packets, in congestion-prone wireless networks the increased number of packets per slice and their size disparity may increase the packet loss rate from buffer overflows. As a form of congestion resilience, this paper recommends packet-size dependent scheduling as a relatively simple way of alleviating the buffer-overflow problem arising from data-partitioned packets. The paper also contributes an analysis of data partitioning and packet sizes as a prelude to considering scheduling regimes. The combination of adaptive channel coding and prioritized packetization for error resilience with packet-size dependent packet scheduling results in a robust streaming scheme specialized for broadband wireless and real-time streaming applications such as video conferencing, video telephony, and telemedicine.

Analysis of the algorithms for congestion management in computer networks

Directory of Open Access Journals (Sweden)

S. Szilágyi

2013-06-01

Full Text Available This paper presents one of the features of DS (Differentiated Services architecture, namely the queuing or congestion management. Packets can be placed into separate buffer queues, on the basis of the DS value. Several forwarding policies can be used to favor high priority packets in different ways. The major reason for queuing is that the router must hold the packet in its memory while the outgoing interface is busy with sending another packet. Our main goal is to compare the performance of the following queuing mechanisms: FIFO (First- In First-Out, CQ (Custom Queuing, PQ (Priority Queuing, WFQ (Weighted Fair Queuing, CBWFQ (Class Based Weighted Fair Queuing and LLQ (Low Latency Queuing.

Real time driver information for congestion management.

Science.gov (United States)

2015-07-01

Traffic demand in the U.S. has grown substantially over the past few years because of the increase in population and : urbanization in large cities. This causes traffic congestion to spread out over U.S. highways and arterials, and subsequently : lea...

Traffic Congestion Detection System through Connected Vehicles and Big Data

Directory of Open Access Journals (Sweden)

Néstor Cárdenas-Benítez

2016-04-01

Full Text Available 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.

Traffic Congestion Detection System through Connected Vehicles and Big Data.

Science.gov (United States)

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.

Congestion management of electric distribution networks through market based methods

DEFF Research Database (Denmark)

Huang, Shaojun

 EVs and HPs. Market-based congestion management methods are the focus of the thesis. They handle the potential congestion at the energy planning stage; therefore, the aggregators can optimally plan the energy consumption and have the least impact on the customers. After reviewing and identifying...... the shortcomings of the existing methods, the thesis fully studies and improves the dynamic tariff (DT) method, and proposes two  new market-based  congestion management methods,  namely the  dynamic subsidy (DS) method and the flexible demand swap method. The thesis improves the DT method from four aspects......Rapidly increasing share of intermittent renewable energy production poses a great challenge of the management and operation of the modern power systems. Deployment of a large number of flexible demands, such as electrical vehicles (EVs) and heat pumps (HPs), is believed to be a promising solution...

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

Directory of Open Access Journals (Sweden)

Ga-Won Lee

2014-04-01

Full Text Available 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.

Marginal cost and congestion in the Italian electricity market: An indirect estimation approach

International Nuclear Information System (INIS)

Bigerna, Simona; Andrea Bollino, Carlo; Polinori, Paolo

2015-01-01

In this paper we construct an indirect measure of the supply marginal cost function for the main generators from the observed bid data in the Italian electricity market in the period 2004–2007. We compute the residual demand function for each generator, taking explicitly into account the issue of transmission line congestion. This procedure allows recovering correct zonal Lerner index and the implied measure of the marginal cost function. We find evidence of a stable U-shaped marginal cost function for three main Italian generators, but a flat function for ENEL, the former national monopolist. The policy relevance of our approach lies in the possibility to offer some empirical knowledge of the marginal cost function of each generator to the regulator to design appropriate policy measures geared to the promotion of competitive market conditions. We propose a new market surveillance mechanism, which is based on the principle of sanctioning excessive deviations from the estimated measure of the marginal cost function presented in this work. -- Highlights: •We construct an indirect measure of the supply marginal cost function. •We compute the residual demand function taking into account transmission line congestion. •We find a general evidence of a stable U-shaped marginal cost function for Italian generators. •We find flat marginal cost function for the former national monopolist. •We use excessive deviations from estimated marginal cost function as a new market surveillance mechanism

Existence for stationary mean-field games with congestion and quadratic Hamiltonians

KAUST Repository

Gomes, Diogo A.

2015-09-03

Here, we investigate the existence of solutions to a stationary mean-field game model introduced by J.-M. Lasry and P.-L. Lions. This model features a quadratic Hamiltonian and congestion effects. The fundamental difficulty of potential singular behavior is caused by congestion. Thanks to a new class of a priori bounds, combined with the continuation method, we prove the existence of smooth solutions in arbitrary dimensions. © 2015 Springer Basel

Short paper: Distributed vehicular traffic congestion detection algorithm for urban environments

OpenAIRE

Milojevic, M.; Rakocevic, V.

2013-01-01

Vehicular traffic congestion is a well-known economic and social problem generating significant costs and safety challenges, and increasing pollution in the cities. Current intelligent transport systems and vehicular networking technologies rely heavily on the supporting network infrastructure which is still not widely available. This paper contributes towards the development of distributed and cooperative vehicular traffic congestion detection by proposing a new vehicle-to-vehicle (V2V) cong...

HYDRAULIC SERVO CONTROL MECHANISM

Science.gov (United States)

Hussey, R.B.; Gottsche, M.J. Jr.

1963-09-17

A hydraulic servo control mechanism of compact construction and low fluid requirements is described. The mechanism consists of a main hydraulic piston, comprising the drive output, which is connected mechanically for feedback purposes to a servo control piston. A control sleeve having control slots for the system encloses the servo piston, which acts to cover or uncover the slots as a means of controlling the operation of the system. This operation permits only a small amount of fluid to regulate the operation of the mechanism, which, as a result, is compact and relatively light. This mechanism is particuiarly adaptable to the drive and control of control rods in nuclear reactors. (auth)

Impact on Congestion and Fuel Consumption of a Cooperative Adaptive Cruise Control System with Lane-Level Position Estimation

Directory of Open Access Journals (Sweden)

Edgar Talavera

2018-01-01

Full Text Available In recent years, vehicular communications systems have evolved and allowed for the improvement of adaptive cruise control (ACC systems to make them cooperative (cooperative adaptive cruise control, CACC. Conventional ACC systems use sensors on the ego-vehicle, such as radar or computer vision, to generate their behavioral decisions. However, by having vehicle-to-X (V2X onboard communications, the need to incorporate perception in the vehicle is drastically reduced. Thus, in this paper a CACC solution is proposed that only uses communications to make its decisions with the help of previous road mapping. At the same time, a method to develop these maps is presented, combining the information of a computer vision system to correct the positions obtained from the navigation system. In addition, the cut-in and cut-out maneuvers for a CACC platoon are taken into account, showing the tests of these situations in real environments with instrumented vehicles. To show the potential of the system in a larger-scale implementation, simulations of the behavior are provided under dense traffic conditions where the positive impact on the reduction of traffic congestion and fuel consumption is appreciated.

Airlines' strategic interactions and airport pricing in a dynamic bottleneck model of congestion

NARCIS (Netherlands)

Silva Montalva, H.E.; Verhoef, E.T.; van den Berg, V.A.C.

2014-01-01

This paper analyzes efficient pricing at a congested airport dominated by a single firm. Unlike much of the previous literature, we combine a dynamic bottleneck model of congestion and a vertical structure model that explicitly considers the role of airlines and passengers. We show that a

Congestion estimation technique in the optical network unit registration process.

Science.gov (United States)

Kim, Geunyong; Yoo, Hark; Lee, Dongsoo; Kim, Youngsun; Lim, Hyuk

2016-07-01

We present a congestion estimation technique (CET) to estimate the optical network unit (ONU) registration success ratio for the ONU registration process in passive optical networks. An optical line terminal (OLT) estimates the number of collided ONUs via the proposed scheme during the serial number state. The OLT can obtain congestion level among ONUs to be registered such that this information may be exploited to change the size of a quiet window to decrease the collision probability. We verified the efficiency of the proposed method through simulation and experimental results.

Impact Analysis of Land Use on Traffic Congestion Using Real-Time Traffic and POI

OpenAIRE

Zhang, Tianqi; Sun, Lishan; Yao, Liya; Rong, Jian

2017-01-01

This paper proposed a new method to describe, compare, and classify the traffic congestion points in Beijing, China, by using the online map data and further revealed the relationship between traffic congestion and land use. The data of the point of interest (POI) and the real-time traffic was extracted from an electronic map of the area in the fourth ring road of Beijing. The POIs were quantified based on the architectural area of the land use; the congestion points were identified based on ...

Compromised Global and Regional Cerebral Blood Flow in Congestive Heart Failure

Energy Technology Data Exchange (ETDEWEB)

Kim, J. S.; Kim, J. J.; Im, K. C.; Moon, D. H. [College of Medicine, Univ. of Ulsan, Seoul (Korea, Republic of)

2003-07-01

It has been known that cerebral perfusion is maintained in patients with congestive heart failure (CHF) by a complex series of compensatory mechanisms. However cognitive impairment is a common problem experienced by patients with CHF and may result from deranged cerebral perfusion. We prospectively investigated the global and regional CBF of patients with CHF and compared the results with that of normal controls. Thirty two patients (M/F: 22/10, 4211 yr) with CHF (LVEF=218.1%) and 10 healthy controls (M/F: 6/4, 398 yr) were prospectively studied. No patients had cerebrovascular disease or other disease affecting cognitive function. All patients and normal controls underwent radionuclide angiography including cerebral hemispheres and aortic arch, and brain perfusion SPECT using Tc-99m ECD. Global CBF was measured non-invasively by the application of Patlak plot graphical analysis. Quantitative rCBF images were obtained from SPECT image using global CBF values, regional/global count ratios, and Lassen's linearization correction algorithm. Difference of regional CBF between CHF and normal control were assessed using a SPM99 without global count normalization (uncorrected p<0.0001, extent threshold>100 voxels). Global CBF (41.54.7 ml/min/100g) of the patients with CHF were significantly lower than those (49.15.7 ml/min/100g) of controls (p<0.001). Regional CBF was significantly decreased in frontal, temporal and parietal neocortex of both cerebral hemispheres compared to normal controls. Regional rCBF of basal ganglia, thalamus, and brain stem were preserved, even though global CBF was variably compromised. Our study show that global CBF is significantly decreased in CHF and regional CBF of frontal, parietal and temporal neocortex is compromised preferentially. Further studies would be needed to investigate the relationship of rCBF change and cognitive impairment in patients with CHF.

Drug therapy for congestive heart failure:appropriate choices can prolong life; Tratamiento farmacologico de la insuficiencia cardiaca congestiva:las elecciones adecuadas pueden prolongar la vida

Energy Technology Data Exchange (ETDEWEB)

Sorrentino, M

1997-09-01

Between one purpose of the insufficiency congestive heart is improve and prolong the quality life. A good multidisciplinary health equipment can help to the improving patients with this disease referred to effective handling interned and ambulatory patients groups. The inhibition mechanism compensate that perpetuate heart congestive insufficiency are a way for reach treatment purposes. Between patients with symptomatic cardiac insufficiency and overload volume is indicated digoxin(Lanoxin) and vasodilators. The enzyme inhibition angiotensin converted improve over life range more than an others vasodilators and is preferred for the systole dysfunction patients.

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

Science.gov (United States)

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...

Long-term congestion management by investment in gas-turbine generators : a cost-benefit analysis

International Nuclear Information System (INIS)

Tuan, L.A.; Bhattacharya, K.

2007-01-01

Load management is one of the most important tasks in the operation of an electric power system. Transmission congestion occurs whenever the grid has one or more violations of the physical, operation, or policy constraints under which it normally operates. In a deregulated electricity market, the independent system operator (ISO) must ensure that contracted power transactions are carried out reliably. Several schemes of congestion management run the risk of increasing electricity prices due to the market power of local generators in congested areas. An alternative is to manage congestion through the installation of reserve gas turbine generators which can be brought online to the system within a short time. The use of gas turbines at different buses in the system can enhance the system in ways of transmission relief during emergency events. This paper proposed a framework for the evaluation of long-term investment by the ISO on gas-turbine generators as a tool for providing transmission congestion relief in the dispatch stage based on cost-benefit analysis. The objective of the framework is to optimally decide the locations and sizes of the generators at different buses in the network in order to minimize the total cost of investment of gas turbines and to minimize total system congestion. A bus-wise cost-benefit analysis was carried out by solving the DC optimal power flow (dc-OPF) model. The CIGRE 32-Bus system was used for the case study. It was shown that network overloading can be significantly reduced with the support of gas turbines at selected buses. The long-term decision of the investment on gas-turbine would depend on the opportunity cost of the gas-turbine with respect to the congestion problem. The gas turbines could also reduce the amount of unserved energy during peak load conditions. 11 refs., 4 tabs., 3 figs

FOUR-YEAR-OLD NAMSAN TUNNEL CONGESTION PRICING SCHEME IN SEOUL

Directory of Open Access Journals (Sweden)

Bongsoo SON, Ph. D.

2002-01-01

Full Text Available The purpose of this paper is to evaluate the effectiveness of the congestion pricing scheme at Namsan #1 and #3 tunnels in downtown Seoul four years after its implementation. The effectiveness of the scheme was measured by the changes of various traffic impacts. The traffic volume of the two tunnels was reduced by up to 25% for the first month. After that time, the traffic volume started to increase again and then exceeded the previous volume level. However, average travel speed of the two tunnel corridors improved by up to 74%. The overall traffic volume of the four alternative routes was increased; nevertheless, their average travel speed increased as well. The number of carpool vehicles occupied by 3 or more persons including the driver during the peak periods was remarkably increased. Before the congestion fee charging, toll-charged vehicles amounted to 68.5% of the total traffic volume of the two tunnels, and then the share dropped to 29% afterwards. The empirical analysis results for the effectiveness of the congestion pricing scheme are very promising.

Chronic congestive heart failure is associated with a phenotypic shift of intramyocardial endothelial cells

NARCIS (Netherlands)

Marijianowski, M. M.; van Laar, M.; Bras, J.; Becker, A. E.

1995-01-01

There is evidence that patients with chronic congestive heart failure have endothelial cell-related abnormalities of the peripheral circulation and the coronary microvasculature. For that reason, we have studied the phenotypic expression of endothelial cells in hearts of patients with congestive

Update in cardiomyopathies and congestive heart failure

Directory of Open Access Journals (Sweden)

The Heart Hospital, London, UK and Monaldi Hospital, Naples, Italy

2012-05-01

Full Text Available This abstract book contains four reports and all abstracts presented to the Joint Meeting: Update in cardiomyopathies and congestive heart failure, 22-23 September 2011 - Naples, Italy, endorsed by the Working Group on Myocardial and Pericardial Diseases (WG 21 of the European Society of Cardiology (ESC.

A Flexible Load Control Strategy for Distribution Network to Reduce the Line Losses and to Eliminate the Transmission Congestion

Directory of Open Access Journals (Sweden)

Beibei Wang

2017-01-01

Full Text Available There are many uncertain factors in the modern distribution network, including the access of renewable energy sources and the heavy load level. The existence of these factors has brought challenges to the stability of the power distribution network, as well as increasing the risk of exceeding transmission capacity of distribution lines. The appearance of flexible load control technology provides a new idea to solve the above problems. Air conditioners (ACs account for a great proportion of all loads. In this paper, the model of dispatching AC loads in the regional power grid is constructed, and the direct load control (DLC method is adopted to reduce the load of ACs. An improved tabu search technique is proposed to solve the problem of network dispatch in distribution systems in order to reduce the resistive line losses and to eliminate the transmission congestion in lines under normal operating conditions. The optimal node solution is obtained to find the best location and reduction capacity of ACs for load control. To demonstrate the validity and effectiveness of the proposed method, a test system is studied. The numerical results are also given in this article, which reveal that the proposed method is promising.

Congestive heart failure as a determinant of postoperative delirium.

Science.gov (United States)

Parente, Daniela; Luís, Clara; Veiga, Dalila; Silva, Hugo; Abelha, Fernando

2013-09-01

Postoperative delirium (POD) is a frequent post-surgical complication that is associated with increased mortality and poor patient outcomes. POD is a complex disorder with multiple risk factors such as pre-existing patient comorbidities and perioperative complications. The aim of this study was to evaluate the incidence of POD and to identify risk factors for the development of POD in a post-anesthesia care unit (PACU). We enrolled 97 adult patients admitted to a PACU over a five-day period (start date September 6, 2010). Patient demographics and intraoperative and postoperative data were collected. Patients were followed for the development of delirium using the Intensive Care Delirium Screening Checklist. Descriptive analyses of variables were used to summarize data, and the Mann-Whitney U test was used to compare continuous variables; the chi-square or Fisher's exact test was used for comparisons. Univariate analysis was performed using simple binary logistic regression with odds ratios (OR) and 95% confidence intervals (95% CI). The significance level for multiple comparisons was controlled by applying the Bonferroni correction for multiple comparisons and variables were deemed significant if p≤0.0025. Six percent of patients developed POD. These patients were older and more likely to have higher American Society of Anesthesiologists (ASA) physical status (83 vs. 22% with ASA III/IV, p=0.004) as well as a higher frequency of congestive heart failure (50 vs. 3%, p=0.003) and a higher Revised Cardiac Risk Index (RCRI) score (33 vs. 6% with RCRI ≥2, p=0.039). The duration of anesthesia for patients with POD was also longer and they received a greater volume of crystalloids, colloids, and erythrocytes during surgery. Congestive heart disease was an independent risk factor for POD (OR 29.3, 95% CI 4.1-210.6; p<0.001). In addition, patients who developed POD had higher in-hospital mortality and longer PACU and hospital stays. Patients who developed POD had longer

Generator Rescheduling under Congested Power System with Wind Integrated Competitive Power Market

Directory of Open Access Journals (Sweden)

Sadhan Gope

2017-02-01

Full Text Available Integration of renewable energy like wind or solar energy creates a huge pressure to the system operator (SO to ensure the congestion free transmission network under deregulated power market. Congestion Management (CM with integration of wind farm in double auction electricity market are described in this work to minimize fuel cost, system losses and locational marginal price (LMP of the system. Location of Wind Farm (WF is identified based by using Bus sensitivity factor (BSF, which is also used for selection of load bus for double auction bidding (DAB. The impacts of wind farm in congested power system under deregulated environment have been investigated in this work. Modified 39-bus New England test system is used for demonstrate the effectiveness of the presented approach by using Sequential Quadratic Programming (SQP.

Intestinal congestion and right ventricular dysfunction: a link with appetite loss, inflammation, and cachexia in chronic heart failure.

Science.gov (United States)

Valentova, Miroslava; von Haehling, Stephan; Bauditz, Juergen; Doehner, Wolfram; Ebner, Nicole; Bekfani, Tarek; Elsner, Sebastian; Sliziuk, Veronika; Scherbakov, Nadja; Murín, Ján; Anker, Stefan D; Sandek, Anja

2016-06-01

Mechanisms leading to cachexia in heart failure (HF) are not fully understood. We evaluated signs of intestinal congestion in patients with chronic HF and their relationship with cachexia. Of the 165 prospectively enrolled outpatients with left ventricular ejection fraction ≤40%, 29 (18%) were cachectic. Among echocardiographic parameters, the combination of right ventricular dysfunction and elevated right atrial pressure (RAP) provided the best discrimination between cachectic and non-cachectic patients [area under the curve 0.892, 95% confidence interval (CI): 0.832-0.936]. Cachectic patients, compared with non-cachectic, had higher prevalence of postprandial fullness, appetite loss, and abdominal discomfort. Abdominal ultrasound showed a larger bowel wall thickness (BWT) in the entire colon and terminal ileum in cachectic than in non-cachectic patients. Bowel wall thickness correlated positively with gastrointestinal symptoms, high-sensitivity C-reactive protein, RAP, and truncal fat-free mass, the latter serving as a marker of the fluid content. Logistic regression analysis showed that BWT was associated with cachexia, even after adjusting for cardiac function, inflammation, and stages of HF (odds ratio 1.4, 95% CI: 1.0-1.8; P-value = 0.03). Among the cardiac parameters, only RAP remained significantly associated with cachexia after multivariable adjustment. Cardiac cachexia was associated with intestinal congestion irrespective of HF stage and cardiac function. Gastrointestinal discomfort, appetite loss, and pro-inflammatory activation provide probable mechanisms, by which intestinal congestion may trigger cardiac cachexia. However, our results are preliminary and larger studies are needed to clarify the intrinsic nature of this relationship. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2016. For permissions please email: journals.permissions@oup.com.

Congestive cardiomyopathy and endobronchial granulomas as manifestations of Churg-Strauss syndrome.

Science.gov (United States)

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

CSRNet: Dilated Convolutional Neural Networks for Understanding the Highly Congested Scenes

OpenAIRE

Li, Yuhong; Zhang, Xiaofan; Chen, Deming

2018-01-01

We propose a network for Congested Scene Recognition called CSRNet to provide a data-driven and deep learning method that can understand highly congested scenes and perform accurate count estimation as well as present high-quality density maps. The proposed CSRNet is composed of two major components: a convolutional neural network (CNN) as the front-end for 2D feature extraction and a dilated CNN for the back-end, which uses dilated kernels to deliver larger reception fields and to replace po...

Temporal-Spatial Analysis of Traffic Congestion Based on Modified CTM

Directory of Open Access Journals (Sweden)

Chenglong Chu

2015-01-01

Full Text Available A modified cell transmission model (CTM is proposed to depict the temporal-spatial evolution of traffic congestion on urban freeways. Specifically, drivers’ adaptive behaviors and the corresponding influence on traffic flows are emphasized. Two piecewise linear regression models are proposed to describe the relationship of flow and density (occupancy. Several types of cellular connections are designed to depict urban rapid roads with on/off-ramps and junctions. Based on the data collected on freeway of Queen Elizabeth, Ontario, Canada, we show that the new model provides a relatively higher accuracy of temporal-spatial evolution of traffic congestions.

Game theoretic analysis of congestion, safety and security networks, air traffic and emergency departments

CERN Document Server

Zhuang, Jun

2015-01-01

Maximizing reader insights into the roles of intelligent agents in networks, air traffic and emergency departments, this volume focuses on congestion in systems where safety and security are at stake, devoting special attention to applying game theoretic analysis of congestion to: protocols in wired and wireless networks; power generation, air transportation and emergency department overcrowding. Reviewing exhaustively the key recent research into the interactions between game theory, excessive crowding, and safety and security elements, this book establishes a new research angle by illustrating linkages between the different research approaches and serves to lay the foundations for subsequent analysis. Congestion (excessive crowding) is defined in this work as all kinds of flows; e.g., road/sea/air traffic, people, data, information, water, electricity, and organisms. Analyzing systems where congestion occurs – which may be in parallel, series, interlinked, or interdependent, with flows one way or both way...

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

Science.gov (United States)

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.

Assessment of congestive heart failure in chest radiographs

International Nuclear Information System (INIS)

Henriksson, L.; Sundin, A.; Smedby, Oe.; Albrektsson, P.

1990-01-01

The effect of observer variations and film-screen quality on the diagnosis of congestive heart failure based on chest radiographs was studied in 27 patients. For each patient, two films were exposed, one with the Kodak Lanex Medium system and one with the Agfa MR 400 system. The films were presented to three observers who assessed the presence of congestive heart failure on a three-graded scale. The results showed no significant difference between the two systems but large systematic differences between the observers. There were also differences between the two ratings by the same observer that could not be explained by the film-screen factor. It is concluded that the choice between these two systems is of little importance in view of the interobserver and intraobserver variability that can exist within the same department. (orig.)

Arteriosclerotic changes in the myocardium, lung, and kidney in dogs with chronic congestive heart failure and myxomatous mitral valve disease

DEFF Research Database (Denmark)

Falk, Bo Torkel; Jönsson, Lennart; Olsen, Lisbeth Høier

2006-01-01

Background: The occurrence of small vessel arteriosclerosis in the myocardium, kidney, and lung in dogs with naturally occurring myxomatous mitral valve disease has not been previously investigated systematically. Methods: Twenty-one dogs with naturally occurring congestive heart failure and 21 age......-matched, sex-matched, and weight-matched control dogs underwent extensive pathological and histopathological examination. Morphometry and scoring of tissue sections were used to measure arterial narrowing and fibrosis in the myocardium, kidney, and lung; and intimal thickness and plaque formation in the aorta...... and pulmonary artery. Results: Dogs with congestive heart failure had significantly more arterial narrowing in the left ventricle (Pdogs. However...

An endoscopic study of upper-GI mucosal changes in patients with congestive heart failure.

Science.gov (United States)

Raja, Kaiser; Kochhar, Rakesh; Sethy, Pradeepta K; Dutta, Usha; Bali, Harinder K; Varma, Jagmohan S

2004-12-01

Congestive heart failure results in an increase in systemic venous pressure that is transmitted to the inferior vena cava and to the hepatic veins. This can cause GI vascular and mucosal congestion. The aim of this study was to define upper-GI mucosal changes in patients with congestive heart failure. A total of 57 patients with congestive heart failure presenting with GI symptoms underwent upper endoscopy. Echocardiography was performed in all patients to determine the ejection fraction and the degree of tricuspid regurgitation. Transabdominal US was performed to measure the diameters of the hepatic veins, the inferior vena cava, and the portal vein. The presence and the severity of gastropathy and duodenopathy were compared with the parameters relating to severity of cardiac failure. Of the 57 patients studied, gastric mucosal changes were observed in 50 (88%), duodenal mucosal changes in 31 (54%), and esophageal mucosal changes in none. Gastric mucosal changes were the following: mosaic-like pattern (n = 50), punctate spots (n = 34), thickened folds (n = 5), watermelon stomach (n = 3), and telangiectasia (n = 10). Duodenal mucosal changes were the following: mosaic-like pattern (n = 29), thickened folds (n = 8), and telangiectasia (n = 2). Upper-GI symptoms were associated with gastropathy ( p = 0.027) and duodenopathy ( p = 0.003). The presence and the severity of duodenopathy showed a high degree of positive correlation with the presence and the severity of gastropathy (gamma value 0.690; p value <0.001). Patients with gastropathy and duodenopathy had higher mean inferior vena cava and hepatic vein diameters than those without gastropathy and duodenopathy. The severity of duodenopathy but not that of gastropathy was significantly associated with increasing severity of tricuspid regurgitation ( p = 0.001), larger portal vein diameter ( p = 0.02), and lower ejection fraction ( p = 0.008). Among patients with congestive cardiac failure with GI symptoms, changes

Social Optimality of Cordon Area Congestion Pricing in an Monocentric City

Directory of Open Access Journals (Sweden)

Harya S Dillon

2015-04-01

Full Text Available Abstrak. Kemacetan lalu lintas merupakan epidemi global yang telah melumpuhkan banyak kota. Dari sudut pandang ekonomi mikro, kemacetan dapat dipandang sebagai eksternalitas negatif dimana diperlukan bea Pigovian sebagai solusi atas ekuilibrium yang kurang optimal tersebut. Eksternalitas ini dirasakan dalam bentuk tundaan perjalanan dan pembangunan kota yang rakus lahan. Meskipun teori mengenai ketepatgunaan bea kemacetan (congestion pricing telah mapan sejak akhir 1970-an, penerapan dan implementasi kebijakan tertunda oleh kendala teknologi. Salah satu bentuk implementasi bayaran kemacetan yang sering dijumpai adalah bea lintas-kordon (cordon charging, dimana penglaju yang masuk ke wilayah pusat dibebani sejumlah biaya. Ketepatgunaan dari bea lintas-kordon telah dikaji secara empiris dan juga dengan simulasi numerik, namun penjelasan teoretis belum dilakukan secara tuntas. Penulis mengembangkan model kota monosentris untuk meneliti dampak kebijakan bea lintas-kordon pada kepadatan kota dan permintaan akan lahan kota (equilibrium rent. Bea lintas-kordon akan menaikkan harga lahan di pusat kota dan memperbesar gradien kurva tawaran-sewa (bid-rent curve. Namun yang lebih penting untuk diperhatikan adalah bahwa besaran ini ditentukan oleh parameter kordon. Dengan demikian dapat disimpulkan bahwa daya manfaat kebijakan ini sangat dipengaruhi oleh pilihan parameter kordon yang dibuat perencana.Kata kunci. kemacetan, bea lintas-kordon, kota monosentris, struktur kotaAbstract. Traffic congestion is a global epidemic that at time has put cities to a state of paralysis. From a microeconomics point of view, congestion can be approached as a negative externality that merits a Pigovian tax to correct the suboptimal equilibrium. Externalities manifest in delays and wasteful urbanization. While the efficiency of congestion pricing has been well established since the late 1970s, policy adoption and implementation have been delayed due to technological

Sensitivity Analysis of Dynamic Tariff Method for Congestion Management in Distribution Networks

DEFF Research Database (Denmark)

Huang, Shaojun; Wu, Qiuwei; Liu, Zhaoxi

2015-01-01

The dynamic tariff (DT) method is designed for the distribution system operator (DSO) to alleviate the congestions that might occur in a distribution network with high penetration of distribute energy resources (DERs). Sensitivity analysis of the DT method is crucial because of its decentralized...... control manner. The sensitivity analysis can obtain the changes of the optimal energy planning and thereby the line loading profiles over the infinitely small changes of parameters by differentiating the KKT conditions of the convex quadratic programming, over which the DT method is formed. Three case...

Sustainable energy management in urban transport: The public's response of road congestion pricing in Thailand

International Nuclear Information System (INIS)

Kunchornrat, Janthana; Pairintra, Rattanachai; Namprakai, Pichai

2008-01-01

Fuel consumption of vehicles is one of the most vigorously debated issues in Thailand. Concerns about the effect of emissions from the vehicles and a significant reliance on imported oil provide legitimate reasons for government action to manage fuel consumption. There are several different policy measures available to affect the fuel-efficient vehicles as well as reduce the amount of driving. This paper presents the major policy measure studies namely congestion pricing, etc. In congestion pricing measure, we conducted a survey of 400 samples in Bangkok area. The purpose of the survey was to inform respondents about a policy designed to reduce freeway congestion and to estimate respondent support for this policy. After receiving extensive information about the policy, respondents were polled on whether they would support, i.e., vote for any or all of these options. The results of the congestion fee survey suggest that 22% of commuting motorists in Bangkok will support congestion fees on the freeways of the region. Public acceptance is substantially enhanced by promising to return at least some of the revenues in the form of reductions in other taxes. (author)

Congestion management in the European electricity market; Engpassmanagement im Europaeischen Strommarkt

Energy Technology Data Exchange (ETDEWEB)

Dieckmann, Birgit

2008-11-24

The author of the contribution under consideration reports on an assessment of methods of congestion management employed in Europe with respect to their effectiveness and identify possible reasons for the misallocation of cross-border transmission capacity. For this, generation structures of European countries and the resulting prices and load flows are analysed. Different power plants and bottlenecks in the transmission network currently cause structural price differences due to a low degree of integration of European electricity markets. By means of congestion management, the formation of a uniform electricity market will be created.

New Brunswick Market Design Committee : Congestion management issues

International Nuclear Information System (INIS)

2001-01-01

The restructuring of the New Brunswick wholesale power market comprises a number of issues that need to be resolved concerning transmission system related policy decisions and detailed design issues. The wholesale market structure, ownership structure, and means of preventing market power abuses all have an impact on the resolution of many of those issues. Some transmission related decisions regarding congestion management must be made, and they are examined in this document. The report includes a discussion of the issues related to congestion on the transmission system, a review of the decisions that remain to be made while proposing a number of alternatives, reviews decisions that other jurisdictions have made in somewhat similar circumstances. Finally, the advantages and disadvantages of each alternative are identified. Several high level transmission tariff design issues requiring to be addressed later in greater detail are listed in this document. 1 tab

Sleeping and resting respiratory rates in dogs and cats with medically-controlled left-sided congestive heart failure.

Science.gov (United States)

Porciello, F; Rishniw, M; Ljungvall, I; Ferasin, L; Haggstrom, J; Ohad, D G

2016-01-01

Sleeping and resting respiratory rates (SRR and RRR, respectively) are commonly used to monitor dogs and cats with left-sided cardiac disease and to identify animals with left-sided congestive heart failure (L-CHF). Dogs and cats with subclinical heart disease have SRRmean values dogs and cats with CHF that is well controlled with medical therapy. In this study, SRR and RRR were measured by the owners of 51 dogs and 22 cats with stable, well-controlled CHF. Median canine SRRmean was 20 breaths/min (7-39 breaths/min); eight dogs were ≥25 breaths/min and one dog only was ≥30 breaths/min. Canine SRRmean was unrelated to pulmonary hypertension or diuretic dose. Median feline SRRmean was 20 breaths/min (13-31 breaths/min); four cats were ≥25 breaths/min and only one cat was ≥30 breaths/min. Feline SRRmean was unrelated to diuretic dose. SRR remained stable during collection in both species with little day-to-day variability. The median canine RRRmean was 24 breaths/min (12-44 breaths/min), 17 were ≥25 breaths/min, seven were ≥30 breaths/min, two were >40 breaths/min. Median feline RRRmean was 24 breaths/min (15-45 breaths/min); five cats had RRRmean ≥25 breaths/min; one had ≥30 breaths/min, and two had ≥40 breaths/min. These data suggest that most dogs and cats with CHF that is medically well-controlled and stable have SRRmean and RRRmean dogs and cats. Copyright © 2015 Elsevier Ltd. All rights reserved.

Decentralized Traffic Management: A Synchronization-Based Intersection Control --- Extended Version

OpenAIRE

Tlig , Mohamed; Buffet , Olivier; Simonin , Olivier

2014-01-01

Controlling the vehicle traffic in large networks remains an important challenge in urban environments and transportation systems. Autonomous vehicles are today considered as a promising approach to deal with traffic control. In this paper, we propose a synchronization-based intersection control mechanism to allow the autonomous vehicle-agents to cross without stopping, i.e., in order to avoid congestions (delays) and energy loss. We decentralize the problem by managing the traffic of each in...

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

Science.gov (United States)

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...

Congestion in a city with a central bottleneck

DEFF Research Database (Denmark)

Fosgerau, Mogens; Palma, André de

2010-01-01

We consider dynamic congestion in an urban setting where trip origins are spatially distributed. All travelers must pass through a downtown bottleneck in order to reach their destination in the CBD. Each traveler chooses departure time to maximize general concave scheduling utility. At equilibriu...

Congestion in a city with a central bottleneck

DEFF Research Database (Denmark)

Fosgerau, Mogens; Palma, André de

2012-01-01

We consider dynamic congestion in an urban setting where trip origins are spatially distributed. All travelers must pass through a downtown bottleneck in order to reach their destination in the CBD. Each traveler chooses departure time to maximize general concave scheduling utility. We find that,...

Game theoretic analysis of congestion, safety and security traffic and transportation theory

CERN Document Server

Zhuang, Jun

2015-01-01

Maximizing reader insights into the interactions between game theory, excessive crowding and safety and security elements in traffic and transportation theory, this book establishes a new research angle by illustrating linkages between different research approaches and through laying the foundations for subsequent analysis. Congestion (excessive crowding) is defined in this work as all kinds of flows; e.g., road/sea/air traffic, people, data, information, water, electricity, and organisms. Analyzing systems where congestion occurs – which may be in parallel, series, interlinked, or interdependent, with flows one way or both ways – this book puts forward new congestion models, breaking new ground by introducing game theory and safety/security. Addressing the multiple actors who may hold different concerns regarding system reliability; e.g. one or several terrorists, a government, various local or regional government agencies, or others with stakes for or against system reliability, this book describes how ...

Rules for congestion management. Evaluation of available of capacity and possibilities for increased counter trade

Energy Technology Data Exchange (ETDEWEB)

NONE

2004-08-01

In the Nordic electricity market, congestion is currently managed using two methods: a combination of price areas (market splitting) and counter-trade. In the planning phase (one day ahead) the main method employed is market splitting, although moving internal bottlenecks to the country border and domestic counter-trade are also used to some degree. Congestion is solved through counter- trade in the operating phase (during the day). In spring 2002, Nordel published a report with proposals for possible changes in Nordic congestion management. The main proposal was to introduce new price areas in the spot market and let the borders of price areas coincide with the physical borders of congestion in the transmission network to a greater degree. It was also proposed to increase the use of counter-trade. Based on feedback from Nordic market players, Nordel decided to carry on the work with congestion management in a new ad hoc group. The group's mandate was a Nordic harmonization of rules and practices for congestion management and a socio-economically efficient utilisation of the transmission grid capacity. Furthermore, the group was asked to investigate how to ensure optimal availability of capacity and to look into the possibilities of increasing usage of counter-trade. The ad hoc working group results are presented in this report. Among the conclusions drawn from the investigations are: 1) A limited increase of counter-trade in the planning phase is feasible for temporary congestion in order to reduce the area price risks for the market players, 2) Market participants should be consulted to get their views on whether and to what extent counter-trade should be increased taking benefits and costs into account. The extent of counter-trade could e.g. be decided as a percentage of NCT with intact grid, 3) Nordel should consider a practice where counter-trading is used to prevent reductions in cross-border capacity due to maintenance, 4) The use of counter-trade in

Rules for congestion management. Evaluation of availability of capacity and possibilities for increased counter trade

Energy Technology Data Exchange (ETDEWEB)

NONE

2004-08-01

In the Nordic electricity market, congestion is currently managed using two methods: a combination of price areas (market splitting) and counter-trade. In the planning phase (one day ahead) the main method employed is market splitting, although moving internal bottlenecks to the country border and domestic counter-trade are also used to some degree. Congestion is solved through counter- trade in the operating phase (during the day). In spring 2002, Nordel published a report with proposals for possible changes in Nordic congestion management. The main proposal was to introduce new price areas in the spot market and let the borders of price areas coincide with the physical borders of congestion in the transmission network to a greater degree. It was also proposed to increase the use of counter-trade. Based on feedback from Nordic market players, Nordel decided to carry on the work with congestion management in a new ad hoc group. The group's mandate was a Nordic harmonization of rules and practices for congestion management and a socio-economically efficient utilisation of the transmission grid capacity. Furthermore, the group was asked to investigate how to ensure optimal availability of capacity and to look into the possibilities of increasing usage of counter-trade. The ad hoc working group results are presented in this report. Among the conclusions drawn from the investigations are: 1) A limited increase of counter-trade in the planning phase is feasible for temporary congestion in order to reduce the area price risks for the market players, 2) Market participants should be consulted to get their views on whether and to what extent counter-trade should be increased taking benefits and costs into account. The extent of counter-trade could e.g. be decided as a percentage of NCT with intact grid, 3) Nordel should consider a practice where counter-trading is used to prevent reductions in cross-border capacity due to maintenance, 4) The use of counter-trade in

Rules for congestion management. Evaluation of availability of capacity and possibilities for increased counter trade

International Nuclear Information System (INIS)

2004-08-01

In the Nordic electricity market, congestion is currently managed using two methods: a combination of price areas (market splitting) and counter-trade. In the planning phase (one day ahead) the main method employed is market splitting, although moving internal bottlenecks to the country border and domestic counter-trade are also used to some degree. Congestion is solved through counter- trade in the operating phase (during the day). In spring 2002, Nordel published a report with proposals for possible changes in Nordic congestion management. The main proposal was to introduce new price areas in the spot market and let the borders of price areas coincide with the physical borders of congestion in the transmission network to a greater degree. It was also proposed to increase the use of counter-trade. Based on feedback from Nordic market players, Nordel decided to carry on the work with congestion management in a new ad hoc group. The group's mandate was a Nordic harmonization of rules and practices for congestion management and a socio-economically efficient utilisation of the transmission grid capacity. Furthermore, the group was asked to investigate how to ensure optimal availability of capacity and to look into the possibilities of increasing usage of counter-trade. The ad hoc working group results are presented in this report. Among the conclusions drawn from the investigations are: 1) A limited increase of counter-trade in the planning phase is feasible for temporary congestion in order to reduce the area price risks for the market players, 2) Market participants should be consulted to get their views on whether and to what extent counter-trade should be increased taking benefits and costs into account. The extent of counter-trade could e.g. be decided as a percentage of NCT with intact grid, 3) Nordel should consider a practice where counter-trading is used to prevent reductions in cross-border capacity due to maintenance, 4) The use of counter-trade in the

A duopoly model with heterogeneous congestion-sensitive customers

NARCIS (Netherlands)

Mandjes, M.R.H.; Timmer, Judith B.

2003-01-01

This paper analyzes a model with multiple firms (providers), and two classes of customers. These customers classes are characterized by their attitude towards `congestion' (caused by other customers using the same resources); a firm is selected on the basis of both the prices charged by the firms,

Cost recovery of congested infrastructure under market power

NARCIS (Netherlands)

Verhoef, Erik T.

2017-01-01

The Mohring–Harwitz (1962) theorem states that the degree of self-financing of congested infrastructure is equal to the elasticity of the capacity cost function in the optimum, so that under neutral scale economies exact self-financing applies. The theorem breaks down when the infrastructure is used

Renal and cardiac function during alpha1-beta-blockade in congestive heart failure

DEFF Research Database (Denmark)

Heitmann, M; Davidsen, U; Stokholm, K H

2002-01-01

The kidney and the neurohormonal systems are essential in the pathogenesis of congestive heart failure (CHF) and the physiologic response. Routine treatment of moderate to severe CHF consists of diuretics, angiotensin-converting enzyme (ACE) inhibition and beta-blockade. The need for control...... of renal function during initiation of ACE-inhibition in patients with CHF is well known. The aim of this study was to investigate whether supplementation by a combined alpha1-beta-blockade to diuretics and ACE-inhibition might improve cardiac function without reducing renal function....

Beneficial effects of metoprolol on myocardial sympathetic function: Evidence from a randomized, placebo-controlled study in patients with congestive heart failure

NARCIS (Netherlands)

de Milliano, Paul A. R.; de Groot, Andre C.; Tijssen, Jan G. P.; van Eck-Smit, Berthe L. F.; van Zwieten, Pieter A.; Lie, Kong I.

2002-01-01

BACKGROUND: We sought to investigate whether beta-blockers exert a presynaptic effect in the myocardium as measured by 123I-metaiodobenzylguanidine. METHODS: The study comprised 59 patients with congestive heart failure, New York Heart Association class II or III, and left ventricular ejection

Macro-mechanics controls quantum mechanics: mechanically controllable quantum conductance switching of an electrochemically fabricated atomic-scale point contact.

Science.gov (United States)

Staiger, Torben; Wertz, Florian; Xie, Fangqing; Heinze, Marcel; Schmieder, Philipp; Lutzweiler, Christian; Schimmel, Thomas

2018-01-12

Here, we present a silver atomic-scale device fabricated and operated by a combined technique of electrochemical control (EC) and mechanically controllable break junction (MCBJ). With this EC-MCBJ technique, we can perform mechanically controllable bistable quantum conductance switching of a silver quantum point contact (QPC) in an electrochemical environment at room temperature. Furthermore, the silver QPC of the device can be controlled both mechanically and electrochemically, and the operating mode can be changed from 'electrochemical' to 'mechanical', which expands the operating mode for controlling QPCs. These experimental results offer the perspective that a silver QPC may be used as a contact for a nanoelectromechanical relay.

Nonholonomic mechanics and control

CERN Document Server

Murray, RM

2015-01-01

This book explores some of the connections between control theory and geometric mechanics; that is, control theory is linked with a geometric view of classical mechanics in both its Lagrangian and Hamiltonian formulations and in particular with the theory of mechanical systems subject to motion constraints. The synthesis of the topic is appropriate as there is a particularly rich connection between mechanics and nonlinear control theory. The book provides a unified treatment of nonlinear control theory and constrained mechanical systems and illustrates the elegant mathematics behind many simple, interesting, and useful mechanical examples. It is intended for graduate students who wish to learn this subject and researchers in the area who want to enhance their techniques. The book contains sections focusing on physical examples and elementary terms, as well as theoretical sections that use sophisticated analysis and geometry. The first four chapters offer preliminaries and background information, while the...

Short-time existence of solutions for mean-field games with congestion

KAUST Repository

Gomes, Diogo A.

2015-11-20

We consider time-dependent mean-field games with congestion that are given by a Hamilton–Jacobi equation coupled with a Fokker–Planck equation. These models are motivated by crowd dynamics in which agents have difficulty moving in high-density areas. The congestion effects make the Hamilton–Jacobi equation singular. The uniqueness of solutions for this problem is well understood; however, the existence of classical solutions was only known in very special cases, stationary problems with quadratic Hamiltonians and some time-dependent explicit examples. Here, we demonstrate the short-time existence of C∞ solutions for sub-quadratic Hamiltonians.

Market Surveillance Panel Report : constrained off payments and other issues in the management of congestion

International Nuclear Information System (INIS)

2003-01-01

In October 2002, the Market Surveillance Panel (MSP), an independent body appointed by and accountable to Ontario's Independent Electricity Market Operator (IMO), expressed concerns regarding the need to enhance transmission capability to relieve congestion. Concerns were also expressed for the lack of outage coordination among generators and transmitters. A stressed transmission system is a barrier to market efficiency and competition. It also prevents low cost generation from running, thereby requiring replacement by more expensive supply. The MSP examined the efficiency of the electricity market by looking at how off payments of the Congestion Management Settlement Credits (CMSC) improve the efficiency of the market. Following a consultation process with market participants, the MSP determined that constrained off CMSC payments could be eliminated without any reduction in market efficiency. This report presents a series of recommendations to reduce constrained off CMSC payments in some cases, and to eliminate them in others. The report also describes the mechanics of a CMSC review for hydroelectric facilities, as well as CMSC payments related to the 25 Hz sub-system. Barriers to effective transmission planning were noted and suggestions for reform were presented

Mitigation of airspace congestion impact on airline networks

DEFF Research Database (Denmark)

Vaaben, Bo Valdemar; Larsen, Jesper

2015-01-01

In recent years European airspace has become increasingly congested and airlines can now observe that en-route capacity constraints are the fastest growing source of flight delays. In 2010 this source of delay accounted for 19% of all flight delays in Europe and has been increasing with an average...

Effectiveness and efficiency of the two trolley system as an infection control mechanism in the operating theatre.

Science.gov (United States)

Tuisawana, Viliame

2009-11-01

A good infection control manager understands the need to prevent a complete cycle of infection. The Infection Control Working Group Manual of Fiji, emphasised that the Cycle of Infection is the series of stage in which infection is spread. Operating theatres have infection control protocols. Most equipments and instruments used in operating theatre circulate within the theatre. The theatre trolleys are a main component in managing an operating theatre but the least recognised. This paper reviews the effectiveness and efficiency of the current two-trolley system as an infection control mechanism in theatre. The paper will discuss infection control using the current trolley system in relation to the layout of Labasa Hospital operating theatre, human resource, equipment standard and random swab results. The following are random swab results of theatre equipments taken by the Infection Control Nurse from 2006 to 2008. The Labasa Hospital Infection Committee have discouraged random swab sample from mid 2008 based on new guidelines on infection control. The two trolley system, in which an allocated outside trolley transports patients from the ward to a semi-sterile area in theatre. The inside trolley which transports the patient to the operating table. The two trolley system means more trolleys, extra staffs for lifting, additional handling of very sick patients, congestion and delay in taking patients to operating table in theatres should be considered. The one-trolley system in theatre greatly reduces the chances of manually lifting patients, thus reducing the risk of patient injury from fall and risk of back injuries to nurses. There are other evident based practices which can compliment the one trolley system for an effective infection control mechanism in theatres. The Fiji Infection Control Manual (2002) emphases the importance of regularly cleaning the environment and equipments in theatre but there is never a mention about using a two trolley system as an

Nutcracker Syndrome Accompanying Pelvic Congestion Syndrome; Color Doppler Sonography and Multislice CT Findings: A Case Report

International Nuclear Information System (INIS)

Inal, Mikail; Karadeniz Bilgili, Mihrace Yasemin; Sahin, Safa

2014-01-01

Nutcracker syndrome (NCS) is a rare pathology, caused by compression of the left renal vein (LRV) between the abdominal aorta (AA) and the superior mesenteric artery (SMA), due to reduction of the angle between AA and SMA. This leads to LRV varices, left gonadal vein varices and therefore, the pelvic congestion syndrome. For this reason, coexistence of NCS and pelvic congestion syndrome has been described. It manifests by hematuria, proteinuria, and nonspecific pelvic pain secondary to pelvic congestion, dyspareunia and persistent genital arousal. We report a 27-year-old woman who experienced hematuria and left flank pain. The diagnosis of NCS accompanied by pelvic congestion syndrome was missed initially, but later on the diagnosis was made by color Doppler ultrasound, abdominal computed tomography (CT) and CT angiography that were later performed. She refused interventional and surgical treatments, and was lost to follow up

Crystal structures of three sterically congested disilanes

Directory of Open Access Journals (Sweden)

Kothanda Rama Pichaandi

2017-03-01

Full Text Available In the three sterically congested silanes, C24H38Si2 (1 (1,1,2,2-tetraisopropyl-1,2-diphenyldisilane, C24H34Br4Si2 (2 [1,1,2,2-tetrakis(2-bromopropan-2-yl-1,2-diphenyldisilane] and C32H38Si2 (3 (1,2-di-tert-butyl-1,1,2,2-tetraphenyldisilane, the Si—Si bond length is shortest in (1 and longest in (2, with (3 having an intermediate value, which parallels the increasing steric congestion. A comparison of the two isopropyl derivatives, (1 and 2, shows a significant increase in the Si—C(ipso distance with the introduction of bromine. Also, in the brominated compound 2, attractive intermolecular Br...Br interactions exist with Br...Br separations ca 0.52 Å shorter than the sum of the van der Waals radii. In compound 2, one of the bromoisopropyl groups is rotationally disordered in an 0.8812 (9:0.1188 (9 ratio. Compound 3 exhibits `whole molecule' disorder in a 0.9645 (7:0.0355 (7 ratio with the Si—Si bonds in the two components making an angle of ca 66°.

Improving UDP/IP Transmission Without Increasing Congestion

Science.gov (United States)

Burleigh, Scott

2006-01-01

Datagram Retransmission (DGR) is a computer program that, within certain limits, ensures the reception of each datagram transmitted under the User Datagram Protocol/Internet Protocol. [User Datagram Protocol (UDP) is considered unreliable because it does not involve a reliability-ensuring connection-initiation dialogue between sender and receiver. UDP is well suited to issuing of many small messages to many different receivers.] Unlike prior software for ensuring reception of UDP datagrams, DGR does not contribute to network congestion by retransmitting data more frequently as an ever-increasing number of messages and acknowledgements is lost. Instead, DGR does just the opposite: DGR includes an adaptive timeout-interval- computing component that provides maximum opportunity for reception of acknowledgements, minimizing retransmission. By monitoring changes in the rate at which message-transmission transactions are completed, DGR detects changes in the level of congestion and responds by imposing varying degrees of delay on the transmission of new messages. In addition, DGR maximizes throughput by not waiting for acknowledgement of a message before sending the next message. All DGR communication is asynchronous, to maximize efficient utilization of network connections. DGR manages multiple concurrent datagram transmission and acknowledgement conversations.

A plausible congestion management scheme for the internal electricity market of the European Union

International Nuclear Information System (INIS)

Perez-Arriaga, I.J.; Olmos, L.

2005-01-01

This paper proposes a scheme for the management of network congestion in the Internal Electricity Market (IEM) of the European Union. This scheme tries to combine the rigor in the treatment of the energy and transmission capacity transactions with the flexibility and pragmatism that are necessary to make the scheme compatible with the current diversity of regulatory approaches and market structures in the Member States participating in the IEM. First, a reference scheme is presented with a complete formulation that jointly deals with the energy and capacity markets. Because of the implementation difficulties of this conceptually ideal approach, a more pragmatic scheme is proposed instead. The core of this scheme is an explicit auction mechanism that must be run prior to any short-term (daily, typically) energy markets. In this auction, where only transmission capacity is traded, both bilateral contracts and energy bids to Power Exchanges can participate in order to acquire the capacity that is necessary to carry out their transactions. Some technical issues related to the practical implementation of the proposed approach are also examined; these include market liquidity, the financial or physical nature of the long-term contracts, the potential problems of 'slicing' transmission capacity and the allocation of congestion rents. Market power issues are ignored. (author)

A plausible congestion management scheme for the internal electricity market of the European Union

Energy Technology Data Exchange (ETDEWEB)

Perez-Arriaga, I.J.; Olmos, L. [Universidad Pontificia Comillas, Madrid (Spain). Instituto de Investigacion Tecnologica

2005-06-01

This paper proposes a scheme for the management of network congestion in the Internal Electricity Market (IEM) of the European Union. This scheme tries to combine the rigor in the treatment of the energy and transmission capacity transactions with the flexibility and pragmatism that are necessary to make the scheme compatible with the current diversity of regulatory approaches and market structures in the Member States participating in the IEM. First, a reference scheme is presented with a complete formulation that jointly deals with the energy and capacity markets. Because of the implementation difficulties of this conceptually ideal approach, a more pragmatic scheme is proposed instead. The core of this scheme is an explicit auction mechanism that must be run prior to any short-term (daily, typically) energy markets. In this auction, where only transmission capacity is traded, both bilateral contracts and energy bids to Power Exchanges can participate in order to acquire the capacity that is necessary to carry out their transactions. Some technical issues related to the practical implementation of the proposed approach are also examined; these include market liquidity, the financial or physical nature of the long-term contracts, the potential problems of 'slicing' transmission capacity and the allocation of congestion rents. Market power issues are ignored. (author)

Uncertainty Management of Dynamic Tariff Method for Congestion Management in Distribution Networks

DEFF Research Database (Denmark)

Huang, Shaojun; Wu, Qiuwei; Cheng, Lin

2016-01-01

The dynamic tariff (DT) method is designed for the distribution system operator (DSO) to alleviate congestions that might occur in a distribution network with high penetration of distributed energy resources (DERs). Uncertainty management is required for the decentralized DT method because the DT...... is de- termined based on optimal day-ahead energy planning with forecasted parameters such as day-ahead energy prices and en- ergy needs which might be different from the parameters used by aggregators. The uncertainty management is to quantify and mitigate the risk of the congestion when employing...

14 CFR 105.21 - Parachute operations over or into a congested area or an open-air assembly of persons.

Science.gov (United States)

2010-01-01

... congested area or an open-air assembly of persons. 105.21 Section 105.21 Aeronautics and Space FEDERAL... congested area of a city, town, or settlement, or an open-air assembly of persons unless a certificate of... over a congested area or an open-air assembly of persons with a fully deployed and properly functioning...

Variables associated with lung congestion as assessed by chest ultrasound in diabetics undergoing hemodialysis

Directory of Open Access Journals (Sweden)

Paulo Roberto Santos

Full Text Available Abstract Introduction: Ultrasound is an emerging method for assessing lung congestion but is still seldom used. Lung congestion is an important risk of cardiac events and death in end-stage renal disease (ESRD patients on hemodialysis (HD. Objective: We investigated possible variables associated with lung congestion among diabetics with ESRD on HD, using chest ultrasound to detect extracellular lung water. Methods: We studied 73 patients with diabetes as the primary cause of ESRD, undergoing regular HD. Lung congestion was assessed by counting the number of B lines detected by chest ultrasound. Hydration status was assessed by bioimpedance analysis and cardiac function by echocardiography. The collapse index of the inferior vena cava (IVC was measured by ultrasonography. All patients were classified according to NYHA score. Correlations of the number of B lines with continuous variables and comparisons regarding the number of B lines according to categorical variables were performed. Multivariate linear regression was used to test the variables as independent predictors of the number of B lines. Results: None of the variables related to hydration status and cardiac function were associated with the number of B lines. In the multivariate analysis, only the IVC collapse index (b = 45.038; p < 0.001 and NYHA classes (b = 13.995; p = 0.006 were independent predictors of the number of B lines. Conclusion: Clinical evaluation based on NYHA score and measurement of the collapsed IVC index were found to be more reliable than bioimpedance analysis to predict lung congestion.

A Novel Congestion Detection Scheme in TCP Over OBS Networks

KAUST Repository

Shihada, Basem; Ho, Pin-Han; Zhang, Qiong

2009-01-01

This paper introduces a novel congestion detection scheme for high-bandwidth TCP flows over optical burst switching (OBS) networks, called statistical additive increase multiplicative decrease (SAIMD). SAIMD maintains and analyzes a number

Correlation of radiological assessment of congestive heart failure with left ventricular end-diastolic pressure

International Nuclear Information System (INIS)

Herman, P.G.; Kahn, A.; Kallman, C.E.; Rojas, K.A.; Bodenheimer, M.M.

1988-01-01

Left ventricular end-diastolic pressure (LVEDP) has been considered a reliable indicator of left ventricular function. The purpose of this study was to correlate the radiologic assessment of congestive heart failure with LVEDP. The population of the study consisted of 85 consecutive cases in four ranges of LVEDP ( 24). The PA chest radiographs obtained 1 day prior to cardiac catherization were assessed for radiological evidence of congestive heart failure and were graded from normal to abnormal (0-3). The results will be summarized in the authors' presentation. The discordance of radiological assessment of congestive heart failure in patients with elevated LVEDP will be discussed in light of recent advances in pathophysiologic understanding of left ventricular function and the impact of new classes of drugs in the management of these patients

Macro-mechanics controls quantum mechanics: mechanically controllable quantum conductance switching of an electrochemically fabricated atomic-scale point contact

Science.gov (United States)

Staiger, Torben; Wertz, Florian; Xie, Fangqing; Heinze, Marcel; Schmieder, Philipp; Lutzweiler, Christian; Schimmel, Thomas

2018-01-01

Here, we present a silver atomic-scale device fabricated and operated by a combined technique of electrochemical control (EC) and mechanically controllable break junction (MCBJ). With this EC-MCBJ technique, we can perform mechanically controllable bistable quantum conductance switching of a silver quantum point contact (QPC) in an electrochemical environment at room temperature. Furthermore, the silver QPC of the device can be controlled both mechanically and electrochemically, and the operating mode can be changed from ‘electrochemical’ to ‘mechanical’, which expands the operating mode for controlling QPCs. These experimental results offer the perspective that a silver QPC may be used as a contact for a nanoelectromechanical relay.

Control-rod driving mechanism

International Nuclear Information System (INIS)

Jodoi, Takashi.

1976-01-01

Purpose: To prevent falling of control rods due to malfunction. Constitution: The device of the present invention has a scram function in particular, and uses principally a fluid pressure as a scram accelerating means. The control rod is held by upper and lower holding devices, which are connected by a connecting mechanism. This connecting mechanism is designed to be detachable only at the lower limit of driving stroke of the control rod so that there occurs no erroneous scram resulting from careless disconnection of the connecting mechanism. Further, scramming operation due to own weight of the scram operating portion such as control rod driving shaft may be effected to increase freedom. (Kamimura, M.)

Smart curtailment for congestion management in LV distribution network

NARCIS (Netherlands)

Haque, A. N.M.M.; Rahman, M. T.; Nguyen, P. H.; Bliek, F. W.

2016-01-01

The rapid proliferation of distributed energy resources (DERs) leads to capacity challenges, i.e. network congestions, in the low-voltage (LV) distribution networks. A number of strategies are being widely studied to tackle the challenges with direct switching actions such as load shedding or power

434 Urban Traffic Congestion and Its Attendant Health Effects on ...

African Journals Online (AJOL)

User

2010-10-17

Oct 17, 2010 ... Keywords: Congestion, Effects, Health, Road Traffic, and Road Users. ..... of transport problems that can be identified are: bad roads, fuel problem (high fuel price .... Cities.www.ghanaweb.com/ghanahomepage/news archive.

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

Science.gov (United States)

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

Urban Partnership Agreement and Congestion Reduction Demonstration : National Evaluation Framework

Science.gov (United States)

2008-11-21

This report provides an analytical framework for evaluating six deployments under the United States Department of Transportation (U.S. DOT) Urban Partnership Agreement (UPA) and Congestion Reduction Demonstration (CRD) Programs. The six UPA/CRD sites...

On revenue recycling and the welfare effects of second-best congestion pricing in a monocentric city

NARCIS (Netherlands)

Tikoudis, I.; Verhoef, E.T.; van Ommeren, J.N.

2015-01-01

This paper examines congestion taxes in a monocentric city with pre-existing labor taxation. When road toll revenue is used to finance labor tax cuts, 35% of the optimal road tax in our numerical model does not reflect marginal external congestion costs, but rather functions as a Ramsey-Mirrlees

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

Science.gov (United States)

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.

Stability Analysis for Car Following Model Based on Control Theory

International Nuclear Information System (INIS)

Meng Xiang-Pei; Li Zhi-Peng; Ge Hong-Xia

2014-01-01

Stability analysis is one of the key issues in car-following theory. The stability analysis with Lyapunov function for the two velocity difference car-following model (for short, TVDM) is conducted and the control method to suppress traffic congestion is introduced. Numerical simulations are given and results are consistent with the theoretical analysis. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

Clinical outcome of ovarian vein embolization in pelvic congestion ...

African Journals Online (AJOL)

Introduction: Pelvic congestion syndrome (PCS), is a condition associated with ovarian vein (OV) incompetence among other causes. It is manifested by chronic pelvic pain with associated dyspareunia and dysmenorrhea. The diagnosis of PCS is often overlooked and the management can be difficult. Traditional therapy for ...

Mendenhall Glacier Visitor Center vehicular and pedestrian traffic congestion study

Science.gov (United States)

2007-05-01

The Mendenhall Glacier Visitor Center of Tongass National Forest in Juneau, Alaska is experiencing vehicular and pedestrian congestion. This study was initiated by the United States Forest Service, Alaska Region, in cooperation with Western Federal L...

Congestion Tolling for Mixed Urban Freight and Passenger Traffic

Directory of Open Access Journals (Sweden)

Xie Chaoda

2017-01-01

Full Text Available This paper investigates the welfare effects of optimal tolling on urban traffic congestion, in a bottleneck model, with mixed freight and passenger users. The users’ marginal utility of time is considered to be varying with time. Under both no-toll equilibrium and socially optimal tolling, the users are found to sort their arrival time according to the increasing rates of marginal utility at the destination. The optimal toll that maximizes social welfare does not change each user's indirect utilit y relative to the no-toll equilibrium, but completely removes the queue, which also removes the barrier of freight carriers to accept congestion pricing by relating their marginal utilities directly to the toll. When the toll is equally rebated, the proposed social optimal tolling is a Pareto improvement relative to the no-toll equilibrium. Those more productive users also suffer more in both no-toll equilibrium and optimal tolling, which indicates that a differentiated redistribution of toll revenues could be an incentive to improve productivity.

Real Driving Emissions in Congested Traffic: A Comparison of Cold and Hot Start

OpenAIRE

Khalfan, A; Andrews, GE; Li, H

2016-01-01

Air quality NO₂ and PM exceedances in cities are common, where congested traffic occurs and the monitoring station is at the roadside. This work investigated real world emissions for a Euro 4 SI vehicle on a congested road by a roadside air quality monitoring station that exceeds European air quality standards for NOx and PM. The PEMS used was the Temet FTIR with Horiba OBS pitot tube exhaust mass flow sensor and gas sampler. Twenty nine hot start repeat journeys were made at different times ...

Congestion management in power systems. Long-term modeling framework and large-scale application

Energy Technology Data Exchange (ETDEWEB)

Bertsch, Joachim; Hagspiel, Simeon; Just, Lisa

2015-06-15

In liberalized power systems, generation and transmission services are unbundled, but remain tightly interlinked. Congestion management in the transmission network is of crucial importance for the efficiency of these inter-linkages. Different regulatory designs have been suggested, analyzed and followed, such as uniform zonal pricing with redispatch or nodal pricing. However, the literature has either focused on the short-term efficiency of congestion management or specific issues of timing investments. In contrast, this paper presents a generalized and flexible economic modeling framework based on a decomposed inter-temporal equilibrium model including generation, transmission, as well as their inter-linkages. Short and long-term effects of different congestion management designs can hence be analyzed. Specifically, we are able to identify and isolate implicit frictions and sources of inefficiencies in the different regulatory designs, and to provide a comparative analysis including a benchmark against a first-best welfare-optimal result. To demonstrate the applicability of our framework, we calibrate and numerically solve our model for a detailed representation of the Central Western European (CWE) region, consisting of 70 nodes and 174 power lines. Analyzing six different congestion management designs until 2030, we show that compared to the first-best benchmark, i.e., nodal pricing, inefficiencies of up to 4.6% arise. Inefficiencies are mainly driven by the approach of determining cross-border capacities as well as the coordination of transmission system operators' activities.

When the heart kills the liver: acute liver failure in congestive heart failure

Directory of Open Access Journals (Sweden)

Saner FH

2009-12-01

Full Text Available Abstract Congestive heart failure as a cause of acute liver failure is rarely documented with only a few cases. Although the pathophysiology is poorly understood, there is rising evidence, that low cardiac output with consecutive reduction in hepatic blood flow is a main causing factor, rather than hypotension. In the setting of acute liver failure due to congestive heart failure, clinical signs of the latter can be absent, which requires an appropriate diagnostic approach. As a reference center for acute liver failure and liver transplantation we recorded from May 2003 to December 2007 202 admissions with the primary diagnoses acute liver failure. 13/202 was due to congestive heart failure, which was associated with a mortality rate of 54%. Leading cause of death was the underlying heart failure. Asparagine transaminase (AST, bilirubin, and international normalized ratio (INR did not differ significantly in surviving and deceased patients at admission. Despite both groups had signs of cardiogenic shock, the cardiac index (CI was significantly higher in the survival group on admission as compared with non-survivors (2.1 L/min/m2 vs. 1.6 L/min/m2, p = 0.04. Central venous - and pulmonary wedge pressure did not differ significantly. Remarkable improvement of liver function was recorded in the group, who recovered from cardiogenic shock. In conclusion, patients with acute liver failure require an appropriate diagnostic approach. Congestive heart failure should always be considered as a possible cause of acute liver failure.

Detection of intra-cardiac thrombi and congestive heart failure in cats using computed tomographic angiography.

Science.gov (United States)

Vititoe, Kyle P; Fries, Ryan C; Joslyn, Stephen; Selmic, Laura E; Howes, Mark; Vitt, Jordan P; O'Brien, Robert T

2018-04-16

Arterial thromboembolism is a life-threatening condition in cats most commonly secondary to cardiac disease. Echocardiography is the reference standard to evaluate for presence of a thrombus. In humans, computed tomographic (CT) angiography is becoming widely used to detect left atrial thrombi precluding the use of sedation. The purpose of this prospective, controlled, methods comparison pilot study was threefold: (1) describe new CT angiography protocol used in awake cats with cardiac disease and congestive heart failure; (2) determine accuracy of continuous and dynamic acquisition CT angiography to identify and characterize cardiac thrombi from spontaneous echocardiographic contrast using transthoracic echocardiography as our reference standard; (3) identify known negative prognostic factors and comorbidities of the thorax that CT angiography may provide that complement or supersede echocardiographic examination. Fourteen cats with heart disease were recruited; 7 with thrombi and 7 with spontaneous echocardiographic contrast. Echocardiography and awake CT angiography were performed using a microdose of contrast. Six of 7 thrombi were identified on CT angiography as filling defects by at least one reviewer within the left auricle (n = 6) and right heart (n = 1). Highest sensitivity (71.4%) was in continuous phase and highest specificity (85.7%) was in dynamic studies with fair to moderate interobserver agreement (0.38 and 0.44). CT angiography identified prognostic cardiac information (left atrial enlargement, congestive heart failure, arterial thromboembolism) and comorbidities (suspected idiopathic pulmonary fibrosis, asthma). This study indicates CT angiography can readily identify cardiac thrombi, important prognostic information and comorbidities, and can be safely performed in cats with cardiac disease and congestive heart failure. © 2018 American College of Veterinary Radiology.

Factors associated with health-related quality of life in stable ambulatory congestive heart failure patients: Systematic review.

Science.gov (United States)

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.

Wind power development in the United States: Effects of policies and electricity transmission congestion

Science.gov (United States)

Hitaj, Claudia

In this dissertation, I analyze the drivers of wind power development in the United States as well as the relationship between renewable power plant location and transmission congestion and emissions levels. I first examine the role of government renewable energy incentives and access to the electricity grid on investment in wind power plants across counties from 1998-2007. The results indicate that the federal production tax credit, state-level sales tax credit and production incentives play an important role in promoting wind power. In addition, higher wind power penetration levels can be achieved by bringing more parts of the electricity transmission grid under independent system operator regulation. I conclude that state and federal government policies play a significant role in wind power development both by providing financial support and by improving physical and procedural access to the electricity grid. Second, I examine the effect of renewable power plant location on electricity transmission congestion levels and system-wide emissions levels in a theoretical model and a simulation study. A new renewable plant takes the effect of congestion on its own output into account, but ignores the effect of its marginal contribution to congestion on output from existing plants, which results in curtailment of renewable power. Though pricing congestion removes the externality and reduces curtailment, I find that in the absence of a price on emissions, pricing congestion may in some cases actually increase system-wide emissions. The final part of my dissertation deals with an econometric issue that emerged from the empirical analysis of the drivers of wind power. I study the effect of the degree of censoring on random-effects Tobit estimates in finite sample with a particular focus on severe censoring, when the percentage of uncensored observations reaches 1 to 5 percent. The results show that the Tobit model performs well even at 5 percent uncensored observations

Congestion management by determining optimal location of TCSC in deregulated power systems

International Nuclear Information System (INIS)

Besharat, Hadi; Taher, Seyed Abbas

2008-01-01

In a deregulated electricity market, it may always not be possible to dispatch all of the contracted power transactions due to congestion of the transmission corridors. The ongoing power system restructuring requires an opening of unused potentials of transmission system due to environmental, right-of-way and cost problems which are major hurdles for power transmission network expansion. Flexible AC transmission systems (FACTSs) devices can be an alternative to reduce the flows in 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 flows in the network. A method to determine the optimal location of thyristor controlled series compensators (TCSCs) has been suggested in this paper based on real power performance index and reduction of total system VAR power losses. (author)

(GIS-T) application for traffic congestion analyses in the De

African Journals Online (AJOL)

generation known as the 'traditional stopwatch and traffic congestion registration ... transportation safety analysis, travel demand analysis, traffic monitoring and .... many transportation agencies use distance measuring instruments (DMIs) in their probe vehicles. ..... Spatial Implications of the Tuberculosis DOTS Strategy in.

Congestion management rules and trading strategies in the Spanish electricity market

Energy Technology Data Exchange (ETDEWEB)

Furio, Dolores; Lucia, Julio J. [Departamento de Economia Financiera y Actuarial, Universidad de Valencia, Avda. Los Naranjos, s/n, 46022 - Valencia (Spain)

2009-01-15

This paper analyses the economic incentives embodied in the rules governing the resolution of transmission constraints in the Spanish wholesale electricity market and the way these incentives may have influenced on the trading behaviour of both the generators and the demand side. The evidence obtained is consistent with them responding to these incentives. In particular, buyers would respond to the way congestion costs are billed to them by abandoning the daily market in favour of the intraday market as far as possible. Additionally, some strategic generators may have been prompted the system operator to require them to inject electricity into the system to solve network congestions. Finally, these results may contribute to shed light on what should be expected of the reform in the aforementioned rules. (author)

Congestion management rules and trading strategies in the Spanish electricity market

International Nuclear Information System (INIS)

Furio, Dolores; Lucia, Julio J.

2009-01-01

This paper analyses the economic incentives embodied in the rules governing the resolution of transmission constraints in the Spanish wholesale electricity market and the way these incentives may have influenced on the trading behaviour of both the generators and the demand side. The evidence obtained is consistent with them responding to these incentives. In particular, buyers would respond to the way congestion costs are billed to them by abandoning the daily market in favour of the intraday market as far as possible. Additionally, some strategic generators may have been prompted the system operator to require them to inject electricity into the system to solve network congestions. Finally, these results may contribute to shed light on what should be expected of the reform in the aforementioned rules. (author)

Determinants of Traffic Congestion in the Metropolis of Douala ...

African Journals Online (AJOL)

On the other hand, urban agglomeration used as a proxy for traffic congestion has a negative effect on urban growth and economic growth. Based on the above results, it is recommended that a remedial infrastructural development plan and a sustainable polycentric land use pattern with alternative efficient mode of public ...

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.

Science.gov (United States)

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

Battling gridlock : congestion fees are working in Europe and Asia, but its questionable if they will succeed in car-crazy North America

Energy Technology Data Exchange (ETDEWEB)

Carnevale, R. [Colleges Integrating Immigrants to Employment, Toronto, ON (Canada); Crawford, E.A. [York Univ., Toronto, ON (Canada). Faculty of Environmental Studies

2008-07-01

This article described different traffic congestion schemes that cities around the world have adopted to ease traffic grid-lock. Congestion fees that discourage road use involve assigning a price to a road based on the demand for using that road. A weekday congestion fee which was imposed on drivers in the city of London in 2003 resulted in a 30 per cent drop in vehicular traffic in the city centre. The pricing structure was independent of vehicle type, distance travelled or time of day. The successful scheme is credited with an increase in cycling and public transit ridership as well as a decrease in accidents and air pollution without hindering business within the congestion zone. However, the effectiveness of congestion fees in North America is questionable. Although San Diego's high-occupancy toll lanes have helped reduce congestion and pollution because the revenue raised is invested in public transportation, objections have been raised regarding plans to implement congestion fees in San Francisco and New York city centres because doing so would prevent those with low incomes from driving in the city. London has responded to such challenges by putting all net revenues derived from the fees back into public transportation. Similar measures were taken in Stockholm, Sweden where massive improvements were made to its transit system prior to introducing congestion fees to avert criticism. In order for congestion fees to be effective and gain public approval, there should be clear objectives that include demand management, good transportation alternatives, revenues that go to public transit and a simple pricing system that uses proven technology. The cumulative annual cost of congestion in 9 urban centres in Canada ranged from $2.3 billion to $3.7 billion in 2002 according to Transport Canada. Analysts have cautioned that congestion schemes would be difficult to duplicate in North American cities that are highly dependent on automobiles. However, the authors

Battling gridlock : congestion fees are working in Europe and Asia, but its questionable if they will succeed in car-crazy North America

International Nuclear Information System (INIS)

Carnevale, R.; Crawford, E.A.

2008-01-01

This article described different traffic congestion schemes that cities around the world have adopted to ease traffic grid-lock. Congestion fees that discourage road use involve assigning a price to a road based on the demand for using that road. A weekday congestion fee which was imposed on drivers in the city of London in 2003 resulted in a 30 per cent drop in vehicular traffic in the city centre. The pricing structure was independent of vehicle type, distance travelled or time of day. The successful scheme is credited with an increase in cycling and public transit ridership as well as a decrease in accidents and air pollution without hindering business within the congestion zone. However, the effectiveness of congestion fees in North America is questionable. Although San Diego's high-occupancy toll lanes have helped reduce congestion and pollution because the revenue raised is invested in public transportation, objections have been raised regarding plans to implement congestion fees in San Francisco and New York city centres because doing so would prevent those with low incomes from driving in the city. London has responded to such challenges by putting all net revenues derived from the fees back into public transportation. Similar measures were taken in Stockholm, Sweden where massive improvements were made to its transit system prior to introducing congestion fees to avert criticism. In order for congestion fees to be effective and gain public approval, there should be clear objectives that include demand management, good transportation alternatives, revenues that go to public transit and a simple pricing system that uses proven technology. The cumulative annual cost of congestion in 9 urban centres in Canada ranged from $2.3 billion to $3.7 billion in 2002 according to Transport Canada. Analysts have cautioned that congestion schemes would be difficult to duplicate in North American cities that are highly dependent on automobiles. However, the authors

Congestion transition in air traffic networks.

Directory of Open Access Journals (Sweden)

Bernardo Monechi

Full Text Available Air Transportation represents a very interesting example of a complex techno-social system whose importance has considerably grown in time and whose management requires a careful understanding of the subtle interplay between technological infrastructure and human behavior. Despite the competition with other transportation systems, a growth of air traffic is still foreseen in Europe for the next years. The increase of traffic load could bring the current Air Traffic Network above its capacity limits so that safety standards and performances might not be guaranteed anymore. Lacking the possibility of a direct investigation of this scenario, we resort to computer simulations in order to quantify the disruptive potential of an increase in traffic load. To this end we model the Air Transportation system as a complex dynamical network of flights controlled by humans who have to solve potentially dangerous conflicts by redirecting aircraft trajectories. The model is driven and validated through historical data of flight schedules in a European national airspace. While correctly reproducing actual statistics of the Air Transportation system, e.g., the distribution of delays, the model allows for theoretical predictions. Upon an increase of the traffic load injected in the system, the model predicts a transition from a phase in which all conflicts can be successfully resolved, to a phase in which many conflicts cannot be resolved anymore. We highlight how the current flight density of the Air Transportation system is well below the transition, provided that controllers make use of a special re-routing procedure. While the congestion transition displays a universal scaling behavior, its threshold depends on the conflict solving strategy adopted. Finally, the generality of the modeling scheme introduced makes it a flexible general tool to simulate and control Air Transportation systems in realistic and synthetic scenarios.

Congestion transition in air traffic networks.

Science.gov (United States)

Monechi, Bernardo; Servedio, Vito D P; Loreto, Vittorio

2015-01-01

Air Transportation represents a very interesting example of a complex techno-social system whose importance has considerably grown in time and whose management requires a careful understanding of the subtle interplay between technological infrastructure and human behavior. Despite the competition with other transportation systems, a growth of air traffic is still foreseen in Europe for the next years. The increase of traffic load could bring the current Air Traffic Network above its capacity limits so that safety standards and performances might not be guaranteed anymore. Lacking the possibility of a direct investigation of this scenario, we resort to computer simulations in order to quantify the disruptive potential of an increase in traffic load. To this end we model the Air Transportation system as a complex dynamical network of flights controlled by humans who have to solve potentially dangerous conflicts by redirecting aircraft trajectories. The model is driven and validated through historical data of flight schedules in a European national airspace. While correctly reproducing actual statistics of the Air Transportation system, e.g., the distribution of delays, the model allows for theoretical predictions. Upon an increase of the traffic load injected in the system, the model predicts a transition from a phase in which all conflicts can be successfully resolved, to a phase in which many conflicts cannot be resolved anymore. We highlight how the current flight density of the Air Transportation system is well below the transition, provided that controllers make use of a special re-routing procedure. While the congestion transition displays a universal scaling behavior, its threshold depends on the conflict solving strategy adopted. Finally, the generality of the modeling scheme introduced makes it a flexible general tool to simulate and control Air Transportation systems in realistic and synthetic scenarios.

Modeling and analyzing cascading dynamics of the Internet based on local congestion information

Science.gov (United States)

Zhu, Qian; Nie, Jianlong; Zhu, Zhiliang; Yu, Hai; Xue, Yang

2018-06-01

Cascading failure has already become one of the vital issues in network science. By considering realistic network operational settings, we propose the congestion function to represent the congested extent of node and construct a local congestion-aware routing strategy with a tunable parameter. We investigate the cascading failures on the Internet triggered by deliberate attacks. Simulation results show that the tunable parameter has an optimal value that makes the network achieve a maximum level of robustness. The robustness of the network has a positive correlation with tolerance parameter, but it has a negative correlation with the packets generation rate. In addition, there exists a threshold of the attacking proportion of nodes that makes the network achieve the lowest robustness. Moreover, by introducing the concept of time delay for information transmission on the Internet, we found that an increase of the time delay will decrease the robustness of the network rapidly. The findings of the paper will be useful for enhancing the robustness of the Internet in the future.

Case of congestive heart failure induced by therapeutic irradiation

Energy Technology Data Exchange (ETDEWEB)

Kushigami, Motohiko; Suruda, Hidetoshi; Mizukoshi, Masato; Umemoto, Masaaki; Fujiwara, Setsuko; Yamamoto, Katsuhiro; Ueno, Yuji; Nishio, Ichiro; Masuyama, Yoshiaki

1985-02-01

Valvular insufficiency in radiation-induced heart disease is very rare. We described a patient, 53 years old woman, who developed congestive heart failure 2.5 years later following radiotherapy for esophageal carcinoma. The findings on examinations including cardiac catheterization revealed pericarditis with effusion, mitral and tricuspid valve insufficiency and pulmonary infarction. (author).

Finding social optima in congestion games with positive externalities

NARCIS (Netherlands)

de Keijzer, B.; Schäfer, G.

2012-01-01

We consider a variant of congestion games where every player i expresses for each resource e and player j a positive externality, i.e., a value for being on e together with player j. Rather than adopting a game-theoretic perspective, we take an optimization point of view and consider the problem of

Accessibility, Congestion and Travel Delays in Dar es Salaam

DEFF Research Database (Denmark)

Melbye, Dea Christine; Møller-Jensen, Lasse; Andreasen, Manja Hoppe

2015-01-01

on to present a review of research into travel speed levels and congestion in Dar es Salaam. A set of city-wide maps of accessibility and delay levels are constructed based on available speed data and road network data obtained from the OpenStreetMap project and the findings are discussed with respect...

Traffic Accident Propagation Properties and Control Measures for Urban Links Based on Cellular Automata

Directory of Open Access Journals (Sweden)

Xian-sheng Li

2013-01-01

Full Text Available With the rapid development of urban transport and the sharp increase in vehicle population, traffic accidents form one of the most important causes of urban traffic congestion other than the imbalance between traffic supply and demand. Traffic congestion causes severe problems, such as environment contamination and energy dissipation. Therefore, it would be useful to analyze the congestion propagation characteristics after traffic accidents. Numerical analysis and computer simulation were two of the typical methods used at present to study the traffic congestion propagation properties. The latter was more widespread as it is more consistent with the actual traffic flow and more visual than the former. In this paper, an improved cellular automata (CA model was presented to analyze traffic congestion propagation properties and to evaluate control strategies. In order to apply them to urban traffic flow simulation, the CA models have been improved and expanded on. Computer simulations were built for congestion not only extending to the upstream intersection, but also the upstream intersection and the entire road network, respectively. Congestion propagation characteristics after road traffic accidents were obtained, and controls of different severities and durations were analyzed. The results provide the theoretical foundation and practical means for the control of congestion.

Efficiency and profit in the NYISO transmission congestion contract market

Energy Technology Data Exchange (ETDEWEB)

Hadsell, Lester; Shawky, Hany A.

2009-11-15

Evidence of speculator profit and TCC price less than congestion charges suggests that additional competition in the TCC auction should be encouraged as a way to increase efficiency and lower the price of this ''insurance'' for hedgers. (author)

Congestion rents and FTR evaluations in mixed-pool-bilateral systems

International Nuclear Information System (INIS)

Liu, Minghai; Gross, George

2008-01-01

Evaluation of key metrics for congestion management, including the congestion rents and the financial transmission rights (FTR) payoffs, requires the efficient allocation of transmission services and the calculation of appropriate locational marginal prices (LMPs). This requirement is particularly acute when there are bilateral transactions coexisting with the centralized pool markets. We propose a new formulation for this purpose, which captures explicitly the contribution of the bilateral transactions to the social welfare. The proposed formulation effectively integrates the pool market and the bilateral transactions on a consistent basis and results in the more efficient allocation of the transmission resources than the conventional tool. We assess analytically the capabilities of the proposed formulation and solution and quantify the improvements in the evaluations over those done using the conventional approach. Such improvements are also illustrated using simulation results on a wide range of test systems including the IEEE 118-bus network. (author)

Road Traffic Congestion Management Based on a Search-Allocation Approach

Directory of Open Access Journals (Sweden)

Raiyn Jamal

2017-03-01

Full Text Available This paper introduces a new scheme for road traffic management in smart cities, aimed at reducing road traffic congestion. The scheme is based on a combination of searching, updating, and allocation techniques (SUA. An SUA approach is proposed to reduce the processing time for forecasting the conditions of all road sections in real-time, which is typically considerable and complex. It searches for the shortest route based on historical observations, then computes travel time forecasts based on vehicular location in real-time. Using updated information, which includes travel time forecasts and accident forecasts, the vehicle is allocated the appropriate section. The novelty of the SUA scheme lies in its updating of vehicles in every time to reduce traffic congestion. Furthermore, the SUA approach supports autonomy and management by self-regulation, which recommends its use in smart cities that support internet of things (IoT technologies.

The efficacy of centralized flow rate control in 802.11-based wireless mesh networks

KAUST Repository

Jamshaid, K.

2013-06-13

Commodity WiFi-based wireless mesh networks (WMNs) can be used to provide last mile Internet access. These networks exhibit extreme unfairness with backlogged traffic sources. Current solutions propose distributed source-rate control algorithms requiring link-layer or transport-layer changes on all mesh nodes. This is often infeasible in large practical deployments. In wireline networks, router-assisted rate control techniques have been proposed for use alongside end-to-end mechanisms. We wish to evaluate the feasibility of establishing similar centralized control via gateways in WMNs. In this paper, we focus on the efficacy of this control rather than the specifics of the controller design mechanism. We answer the question: Given sources that react predictably to congestion notification, can we enforce a desired rate allocation through a single centralized controller? The answer is not obvious because flows experience varying contention levels, and transmissions are scheduled by a node using imperfect local knowledge. We find that common router-assisted flow control schemes used in wired networks fail in WMNs because they assume that (1) links are independent, and (2) router queue buildups are sufficient for detecting congestion. We show that non-work-conserving, rate-based centralized scheduling can effectively enforce rate allocation. It can achieve results comparable to source rate limiting, without requiring any modifications to mesh routers or client devices. 2013 Jamshaid et al.; licensee Springer.

Monitoring the effect of football match congestion on hamstring strength and lower limb flexibility

DEFF Research Database (Denmark)

Wollin, Martin; Thorborg, Kristian; Pizzari, Tania

2018-01-01

OBJECTIVES: To investigate the effect of competitive football match congestion on hamstring strength and lower limb flexibility. DESIGN: Repeated measures. SETTING: Elite male youth football. PARTICIPANTS: Fifteen male elite youth football players from the national football association centre of ....... CONCLUSION: Isometric hamstring strength and pain can be considered for inclusion in-season to monitor player's post-match hamstring recovery characteristics during congested match fixtures.......OBJECTIVES: To investigate the effect of competitive football match congestion on hamstring strength and lower limb flexibility. DESIGN: Repeated measures. SETTING: Elite male youth football. PARTICIPANTS: Fifteen male elite youth football players from the national football association centre...... of excellence were included (age = 15.81 ±0.65 years, height = 171.95 ±6.89 cm, weight = 65.93 ±7.53 kg). MAIN OUTCOME MEASURES: Hamstring strength and pain, ankle dorsiflexion, hip extension, knee extension and flexion range of motion. RESULTS: Hamstring strength was highest at baseline and significantly...

123I-meta-iodo-benzyl-guanidine myocardial scintigraphy and congestive heart failure: current data and perspective

International Nuclear Information System (INIS)

Agostini, D.; Darlas, Y.; Quennelle, F.; Bouvard, G.; Scanu, P.; Grollier, G.; Potier, J.C.; Babatasi, G.; Belin, A.

1997-01-01

Congestive heart failure is often associated with an impairment of the sympathetic nervous system, i.e., global hyperactivity and regional impairment of the adrenergic system. Cardiac 123 I-MIBG scintigraphy is a radionuclide technique which can explore the presynaptic adrenergic function. Myocardial MIBG fixation is decreased in congestive heart failure, reflecting a reduction of norepinephrine uptake by the myocardial presynaptic nerve endings. The impairment of presynaptic function occurs early in the disease and is actually involved in the pathogenesis of cardiac failure. Cardiac MIBG scintigraphy is a useful tool to explore the myocardial adrenergic stores in patients with congestive heart failure. It could be proposed in patients with severe ventricular dysfunction in order to assist physicians in setting-up the timing of heart transplantation. (authors)

Congestion patterns of electric vehicles with limited battery capacity

Science.gov (United States)

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

Congestion patterns of electric vehicles with limited battery capacity.

Science.gov (United States)

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.

Characterizing Longitude-Dependent Orbital Debris Congestion in the Geosynchronous Orbit Regime

Science.gov (United States)

Anderson, Paul V.

The geosynchronous orbit (GEO) is a unique commodity of the satellite industry that is becoming increasingly contaminated with orbital debris, but is heavily populated with high-value assets from the civil, commercial, and defense sectors. The GEO arena is home to hundreds of communications, data transmission, and intelligence satellites collectively insured for an estimated 18.3 billion USD. As the lack of natural cleansing mechanisms at the GEO altitude renders the lifetimes of GEO debris essentially infinite, conjunction and risk assessment must be performed to safeguard operational assets from debris collisions. In this thesis, longitude-dependent debris congestion is characterized by predicting the number of near-miss events per day for every longitude slot at GEO, using custom debris propagation tools and a torus intersection metric. Near-miss events with the present-day debris population are assigned risk levels based on GEO-relative position and speed, and this risk information is used to prioritize the population for debris removal target selection. Long-term projections of debris growth under nominal launch traffic, mitigation practices, and fragmentation events are also discussed, and latitudinal synchronization of the GEO debris population is explained via node variations arising from luni-solar gravity. In addition to characterizing localized debris congestion in the GEO ring, this thesis further investigates the conjunction risk to operational satellites or debris removal systems applying low-thrust propulsion to raise orbit altitude at end-of-life to a super-synchronous disposal orbit. Conjunction risks as a function of thrust level, miss distance, longitude, and semi-major axis are evaluated, and a guidance method for evading conjuncting debris with continuous thrust by means of a thrust heading change via single-shooting is developed.

Nationwide SIP Telephony Network Design to Prevent Congestion Caused by Disaster

Science.gov (United States)

Satoh, Daisuke; Ashitagawa, Kyoko

We present a session initiation protocol (SIP) network design for a voice-over-IP network to prevent congestion caused by people calling friends and family after a disaster. The design increases the capacity of SIP servers in a network by using all of the SIP servers equally. It takes advantage of the fact that equipment for voice data packets is different from equipment for signaling packets in SIP networks. Furthermore, the design achieves simple routing on the basis of telephone numbers. We evaluated the performance of our design in preventing congestion through simulation. We showed that the proposed design has roughly 20 times more capacity, which is 57 times the normal load, than the conventional design if a disaster were to occur in Niigata Prefecture struck by the Chuetsu earthquake in 2004.

On the inefficiency of equilibria in linear bottleneck congestion games

NARCIS (Netherlands)

B. de Keijzer (Bart); G. Schäfer (Guido); O. Telelis (Orestis); S. Kontogiannis (Spyros); E. Koutsoupias (Elias); P.G. Spirakis (Paul)

2010-01-01

htmlabstractWe 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

Embolization to treat pelvic congestion syndrome and vulval varicose veins.

NARCIS (Netherlands)

Vleuten, C.J.M. van der; Kempen, J.A.L. van; Schultze Kool, L.J.

2012-01-01

OBJECTIVE: To evaluate the efficacy of embolization for treating the symptoms of pelvic congestion syndrome (PCS). METHODS: Twenty-one women with PCS who were treated with embolization at Radboud University Nijmegen Medical Centre between 2003 and 2008 were sent a questionnaire about their symptoms

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

Science.gov (United States)

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...

Transmission expansion cost allocation based on cooperative game theory for congestion relief

Energy Technology Data Exchange (ETDEWEB)

Erli, Ge; Takahasi, Kazuhiro; Kurihara, Ikuo [Central Research Inst. of Electric Power Industry, Tokyo (Japan); Luonan Chen [Osaka Sangyo Univ., Osaka (Japan)

2005-01-01

In conventional power systems, upstream and downstream of power were distinct. However, due to the competition, power injection and sink can appear at unexpected locations, and cost sharing for such a new power system configuration must be considered. This paper proposes a scheme for transmission expansion cost allocation among electric market participants by using Core and Nucleolus concepts of game theory, which are developed particularly for the transmission users. A solution of the n-person cooperative game is adopted to distribute the line transmission expansion cost among the players. Congestion is assumed to be the transmission constraint, and expansion of transmission line is expected to relieve transmission congestion. A case study is illustrated to demonstrate the proposed method. (Author)

Location matters: The impact of renewable power on transmission congestion and emissions

International Nuclear Information System (INIS)

Hitaj, Claudia

2015-01-01

Many governments offer subsidies for renewable power to reduce greenhouse gas emissions in the power sector. However, most support schemes for renewable power do not take into account that emissions depend on the location of renewable and conventional power plants within an electricity grid. I simulate optimal power flow in a test grid when 4 renewable power plants connect to the grid across 24 potential sites, amounting to over 10,000 configurations. Each configuration is associated with different levels of emissions and renewable power output. I find that emission reductions vary by a factor of 7 and that curtailment due to transmission congestion is more likely when renewable power plants are concentrated in an area of the grid with low demand. Large cost savings could be obtained by allowing subsidies for renewable power to vary across locations according to abatement potential or by replacing subsidies with a price on emissions. - Highlights: • Analyze the impact of renewable power plant location on congestion and emissions. • Simulate optimal power flow in a test grid for over 10,000 configurations. • Determine that emission reductions vary by a factor of 7. • Find that renewable power is curtailed due to transmission congestion. • Pricing emissions is most efficient since abatement potential varies across locations.

Control of a mechanical gripper with a fuzzy controller

International Nuclear Information System (INIS)

Alberdi, J.; Barcala, J.M.; Gamero, E.; Navarrete, J.J.

1995-01-01

A fuzzy logic system is used to control a mechanical gripper. System is based in a NLX230 fuzzy micro controller. Control rules are programmed by a 68020 microprocessor in the micro controller memory. Stress and its derived are used as feedback signals in the control. This system can adapt its effort to the mechanical resistance of the object between the fingers. (Author)

Managing congestion in distribution grids - Market design consideration. How heat pumps can deliver flexibility though well-designed markets and virtual power plant technology

Energy Technology Data Exchange (ETDEWEB)

Holmberg Rasmussen, L. [NEAS Energy, Aalborg (Denmark); Bang, C.; Togeby, M. [Ea Energy Analyses, Copenhagen (Denmark)

2012-10-15

Heat pumps can be used to reduce oil and natural gas consumption and can assist in the integration of increased amounts of wind power in the electricity system. The new electricity demand may increase the value of electricity generated by wind power. This can be the result even without any advanced control of the heat pumps. However, heat pumps can be controlled according to prices, and this can both reduce the energy cost for end-users and be beneficial for the energy system. Variable prices can reflect spot prices, and in the future, operation of heat pumps may also reflect more dynamic prices, for example by delivering regulating power. Regulating power prices can be attractive for the end-user because the variation is considerable and includes many low prices. Heat pumps (and also electric vehicles) may potentially create overloading of electricity lines. Distribution grids in particular may be challenged if a large number of these units draw electricity at the same time. This challenge can be amplified when heat pumps react to price signals. The economic optimisation of the heat pump operation may result in an increased correlation of their electricity demand. The price signal may lead to a loss of diversity in the on/off cycles of the control. In the future it is quite foreseeable that heat pumps could deliver regulating power, thereby assisting in the maintenance of the balance in an overall system with significant wind power. Thus another example of a potential problem would be if all heat pumps react to the same price signal at the same time (i.e. delivering down regulation by switching on), as this could also result in the overloading of local distribution networks. Seen in light of the focus on smart grid solutions, the ideal response to the above congestion examples would be to send a high distribution tariff for the relevant time to the areas where congestion is likely. This would solve the local problem, while at the same time allow the large majority

Balancing mechanism status: November 2009

International Nuclear Information System (INIS)

2009-01-01

RTE ensures the real-time balance between production and consumption and deals with congestion on the French electricity system. The Balancing Mechanism assists in the accomplishment of this task. As in many countries, and after extensive dialogue with representatives from the market's various players, RTE proposes a Balancing Mechanism in the form of a permanent and transparent system of calls for tender. The system is open to everyone and provides a real-time reserve of power that can be used for balancing either upward or downward. RTE takes advantage of these offers according to economic precedence, taking into account the system's operating conditions. It pays for them at the offer price. There are two types of offer: - Upward offer: increase in production, decrease in consumption, imports, - Downward offer: decrease in production, increase in consumption, exports. For a Balancing Entity, an offer systematically consists of: a balancing direction (upward/downward), a time period, a price that may vary according to six time slots. RTE publishes each month a Balancing Mechanism Report. which includes the following information: - energy volumes activated to ensure the balance of the system and to resolve congestion; - minimum and maximum prices of offers activated to balance the system; - daily trends calculated according to the predominant value of the overall upward or downward trend; - balancing shares by technology (nuclear, thermal, hydraulic); - characteristics of the five most activated balancing entities; - balances/imbalances accounts and production/consumption overcharge; - congestion curbing costs on the French electricity system; - energy volumes activated to ensure the balance of the system according to contracts between RTE and other Balance Responsible entities (UK, Belgium, Italy, Germany, Switzerland); - reliability of the provisional data supplied by RTE about the balancing trend; - availability of RTE's information services (planning, balancing

Balancing mechanism status: May 2009

International Nuclear Information System (INIS)

2009-01-01

RTE ensures the real-time balance between production and consumption and deals with congestion on the French electricity system. The Balancing Mechanism assists in the accomplishment of this task. As in many countries, and after extensive dialogue with representatives from the market's various players, RTE proposes a Balancing Mechanism in the form of a permanent and transparent system of calls for tender. The system is open to everyone and provides a real-time reserve of power that can be used for balancing either upward or downward. RTE takes advantage of these offers according to economic precedence, taking into account the system's operating conditions. It pays for them at the offer price. There are two types of offer: - Upward offer: increase in production, decrease in consumption, imports, - Downward offer: decrease in production, increase in consumption, exports. For a Balancing Entity, an offer systematically consists of: a balancing direction (upward/downward), a time period, a price that may vary according to six time slots. RTE publishes each month a Balancing Mechanism Report. which includes the following information: - energy volumes activated to ensure the balance of the system and to resolve congestion; - minimum and maximum prices of offers activated to balance the system; - daily trends calculated according to the predominant value of the overall upward or downward trend; - balancing shares by technology (nuclear, thermal, hydraulic); - characteristics of the five most activated balancing entities; - balances/imbalances accounts and production/consumption overcharge; - congestion curbing costs on the French electricity system; - energy volumes activated to ensure the balance of the system according to contracts between RTE and other Balance Responsible entities (UK, Belgium, Italy, Germany, Switzerland); - reliability of the provisional data supplied by RTE about the balancing trend; - availability of RTE's information services (planning, balancing

Standardized evaluation of lung congestion during COPD exacerbation better identifies patients at risk of dying

Directory of Open Access Journals (Sweden)

Høiseth AD

2013-12-01

Full Text Available Arne Didrik Høiseth,1 Torbjørn Omland,1 Bo Daniel Karlsson,2 Pål H Brekke,1 Vidar Søyseth11Cardiothoracic Research Group, Division of Medicine, Akershus University Hospital and Institute of Clinical Medicine, University of Oslo, Oslo, Norway; 2Deptartment of Radiology, Akershus University Hospital, Lørenskog, NorwayBackground: Congestive heart failure is underdiagnosed in patients with chronic obstructive pulmonary disease (COPD. Pulmonary congestion on chest radiograph at admission for acute exacerbation of COPD (AECOPD is associated with an increased risk of mortality. A standardized evaluation of chest radiographs may enhance prognostic accuracy.Purpose: We aimed to evaluate whether a standardized, liberal assessment of pulmonary congestion is superior to the routine assessment in identifying patients at increased risk of long-term mortality, and to investigate the association of heart failure with N-terminal prohormone of brain natriuretic peptide (NT-proBNP concentrations.Material and methods: This was a prospective cohort study of 99 patients admitted for AECOPD. Chest radiographs obtained on admission were routinely evaluated and then later evaluated by blinded investigators using a standardized protocol looking for Kerley B lines, enlarged vessels in the lung apex, perihilar cuffing, peribronchial haze, and interstitial or alveolar edema, defining the presence of pulmonary congestion. Adjusted associations with long-term mortality and NT-proBNP concentration were calculated.Results: The standardized assessment was positive for pulmonary congestion in 32 of the 195 radiographs (16% ruled negative in the routine assessment. The standardized assessment was superior in predicting death during a median follow up of 1.9 years (P=0.022, and in multivariable analysis, only the standardized assessment showed a significant association with mortality (hazard ratio 2.4, 95% confidence interval [CI] 1.2–4.7 (P=0.016 and NT-proBNP (relative

Control rod driving mechanism

International Nuclear Information System (INIS)

Ooshima, Yoshio.

1983-01-01

Purpose: To perform reliable scram operation, even if abnormality should occur in a system instructing scram operation in FBR type reactors. Constitution: An aluminum alloy member to be melt at a predetermined temperature (about 600sup(o)C) is disposed to a connection part between a control rod and a driving mechanism, whereby the control rod is detached from the driving mechanism and gravitationally fallen to the reactor core. (Ikeda, J.)

Congestion Service Facilities Location Problem with Promise of Response Time

Directory of Open Access Journals (Sweden)

Dandan Hu

2013-01-01

Full Text Available In many services, promise of specific response time is advertised as a commitment by the service providers for the customer satisfaction. Congestion on service facilities could delay the delivery of the services and hurts the overall satisfaction. In this paper, congestion service facilities location problem with promise of response time is studied, and a mixed integer nonlinear programming model is presented with budget constrained. The facilities are modeled as M/M/c queues. The decision variables of the model are the locations of the service facilities and the number of servers at each facility. The objective function is to maximize the demands served within specific response time promised by the service provider. To solve this problem, we propose an algorithm that combines greedy and genetic algorithms. In order to verify the proposed algorithm, a lot of computational experiments are tested. And the results demonstrate that response time has a significant impact on location decision.

Incorporating travel-time reliability into the congestion management process : a primer.

Science.gov (United States)

2015-02-01

This primer explains the value of incorporating travel-time reliability into the Congestion Management Process (CMP) : and identifies the most current tools available to assist with this effort. It draws from applied research and best practices : fro...

Time allocation shifts and pollutant exposure due to traffic congestion: an analysis using the national human activity pattern survey.

Science.gov (United States)

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.

Decisions of hypermarkets location in dense urban area – effects on streets network congestion in the Bucharest case

Directory of Open Access Journals (Sweden)

Eugen ROSCA

2008-01-01

Full Text Available The paper represents some partial results of the research carried out by the Transportation, Traffic and Logistics Department - University POLITEHNICA of Bucharest, funded by the Romanian Ministry of Research and Education through the National University Research Council. In this paper we provide: a brief description of the interrelation between the life style changes of Romanian people during the last decades and the car traffic congestion in large cities; the streets network modelling of a radial-circular urban structure (the characteristic of a historically developed city as Bucharest city is, in case of car traffic congestion; the assessment model of the additional car traffic congestion for certain locations with large attractivity. Having an important effect on the entire lifestyle of urban people, the decision of a hypermarket location might be a complex one, taking into consideration the new leisure and shopping tendencies but also the additional car traffic congestion caused by the chosen location.

Estimating Value of Congestion and of Reliability from Observation of Route Choice Behavior of Car Drivers

DEFF Research Database (Denmark)

Prato, Carlo Giacomo; Rasmussen, Thomas Kjær; Nielsen, Otto Anker

2014-01-01

In recent years, a consensus has been reached about the relevance of calculating the value of congestion and the value of reliability for better understanding and therefore better prediction of travel behavior. The current study proposed a revealed preference approach that used a large amount...... both congestion and reliability terms. Results illustrated that the value of time and the value of congestion were significantly higher in the peak period because of possible higher penalties for drivers being late and consequently possible higher time pressure. Moreover, results showed...... that the marginal rate of substitution between travel time reliability and total travel time did not vary across periods and traffic conditions, with the obvious caveat that the absolute values were significantly higher for the peak period. Last, results showed the immense potential of exploiting the growing...

Existence for stationary mean-field games with congestion and quadratic Hamiltonians

KAUST Repository

Gomes, Diogo A.; Mitake, Hiroyoshi

2015-01-01

Here, we investigate the existence of solutions to a stationary mean-field game model introduced by J.-M. Lasry and P.-L. Lions. This model features a quadratic Hamiltonian and congestion effects. The fundamental difficulty of potential singular

Self-management of congestive heart failure among elderly men in Japan.

Science.gov (United States)

Sano, Motohiro; Majima, Tomoko

2018-04-01

The purpose of this study was to explore the process of self-management in elderly male patients with congestive heart failure among those who have had not needed re-hospitalization for more than 2 years. Semi-structured interviews were conducted with 10 male congestive heart failure patients. Interviews were audio-recorded and transcribed verbatim. Data were analysed using the modified grounded theory approach. As a result of the analysis, the core concept identified was a process of living life such that symptoms do not worsen, while balancing good choices and preferences. By trial and error, the men tried to find the limits of physical capacity and dietary choices that would lead to the worsening of symptoms, while also trying to maintain quality of life to the extent possible. © 2018 John Wiley & Sons Australia, Ltd.

Control mechanisms for ecological-economic systems

CERN Document Server

Burkov, Vladimir N; Shchepkin, Alexander V

2015-01-01

This monograph presents and analyzes the optimization, game-theoretic and simulation models of control mechanisms for ecological-economic systems. It is devoted to integrated assessment mechanisms for total risks and losses, penalty mechanisms, risk payment mechanisms, financing and costs compensation mechanisms for risk level reduction, sales mechanisms for risk level quotas, audit mechanisms, mechanisms for expected losses reduction, economic motivation mechanisms, optimization mechanisms for regional environmental (risk level reduction) programs, and mechanisms for authorities' interests coordination. The book is aiming at undergraduate and postgraduate students, as well as at experts in mathematical modeling and control of ecological economic, socioeconomic and organizational systems.

Returns to damage under undesirable congestion and damages to return under desirable congestion measured by DEA environmental assessment with multiplier restriction: Economic and energy planning for social sustainability in China

International Nuclear Information System (INIS)

Sueyoshi, Toshiyuki; Yuan, Yan

2016-01-01

can reduce the industrial and regional imbalances. As a result, China can enhance the level of social sustainability. Finally, the municipalities need strict regulation on traffic control in these metropolitan areas and a fuel mix shift from coal combustion to natural gas and renewable energies (e.g., solar, water, and nuclear generations). The fuel mix strategy, along with the structure change (e.g., from manufacturing to service and from public to private energy firms), will be a major industrial policy issue for China in near future. - Highlights: • This study explores analytical linkages on a concept on “congestion.” • Chinese government paid attention to economic prosperity, but not on environmental pollution. • There was an increasing trend in improving social sustainability. • Energy policy has been focused upon well-developed municipalities and large provinces. • A fuel mix strategy will be an important industrial policy for Chinese future.

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

Science.gov (United States)

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.

Flow control and routing techniques for integrated voice and data networks

Science.gov (United States)

Ibe, O. C.

1981-10-01

We consider a model of integrated voice and data networks. In this model the network flow problem is formulated as a convex optimization problem. The objective function comprises two types of cost functions: the congestion cost functions, which limit the average input traffic to values compatible with the network conditions; and the rate limitation cost functions, which ensure that all conversations are fairly treated. A joint flow control and routing algorithm is constructed which determines the routes for each conversation, and effects flow control by setting voice packet lengths and data input rates in a manner that achieves optimal tradeoff between each user's satisfaction and the cost of network congestion. An additional congestion control protocol is specified which could be used in conjunction with the algorithm to make the latter respond more dynamically to network congestion.

Is congestion pricing a first-best strategy in transport policy? A critical review of arguments

OpenAIRE

R H M Emmerink; P Nijkamp; P Rietveld

1995-01-01

In this paper, the arguments used in the literature pro and contra congestion pricing are analysed. Although it is a first-best instrument in theory, it is argued that the assumptions needed to arrive at this conclusion oversimplify reality. In practice, congestion pricing is a second-best instrument with some advantages over other second-best instruments, but it will also give rise to numerous problems, as discussed in the paper. These problems will be illustrated with the Dutch attempts to ...

Associations between ambient air pollution and daily mortality in a cohort of congestive heart failure: Case-crossover and nested case-control analyses using a distributed lag nonlinear model.

Science.gov (United States)

Buteau, Stephane; Goldberg, Mark S; Burnett, Richard T; Gasparrini, Antonio; Valois, Marie-France; Brophy, James M; Crouse, Dan L; Hatzopoulou, Marianne

2018-04-01

Persons with congestive heart failure may be at higher risk of the acute effects related to daily fluctuations in ambient air pollution. To meet some of the limitations of previous studies using grouped-analysis, we developed a cohort study of persons with congestive heart failure to estimate whether daily non-accidental mortality were associated with spatially-resolved, daily exposures to ambient nitrogen dioxide (NO 2 ) and ozone (O 3 ), and whether these associations were modified according to a series of indicators potentially reflecting complications or worsening of health. We constructed the cohort from the linkage of administrative health databases. Daily exposure was assigned from different methods we developed previously to predict spatially-resolved, time-dependent concentrations of ambient NO 2 (all year) and O 3 (warm season) at participants' residences. We performed two distinct types of analyses: a case-crossover that contrasts the same person at different times, and a nested case-control that contrasts different persons at similar times. We modelled the effects of air pollution and weather (case-crossover only) on mortality using distributed lag nonlinear models over lags 0 to 3 days. We developed from administrative health data a series of indicators that may reflect the underlying construct of "declining health", and used interactions between these indicators and the cross-basis function for air pollutant to assess potential effect modification. The magnitude of the cumulative as well as the lag-specific estimates of association differed in many instances according to the metric of exposure. Using the back-extrapolation method, which is our preferred exposure model, we found for the case-crossover design a cumulative mean percentage changes (MPC) in daily mortality per interquartile increment in NO 2 (8.8 ppb) of 3.0% (95% CI: -0.9, 6.9%) and for O 3 (16.5 ppb) 3.5% (95% CI: -4.5, 12.1). For O 3 there was strong confounding by weather

Short-time existence of solutions for mean-field games with congestion

KAUST Repository

Gomes, Diogo A.; Voskanyan, Vardan K.

2015-01-01

We consider time-dependent mean-field games with congestion that are given by a Hamilton–Jacobi equation coupled with a Fokker–Planck equation. These models are motivated by crowd dynamics in which agents have difficulty moving in high-density areas

Bisoprolol for congestive heart failure

DEFF Research Database (Denmark)

Rosenberg, J.; Gustafsson, F.

2008-01-01

Background: beta-Blockers are a cornerstone in the treatment of systolic heart failure treatment, but not all beta-blockers are effective or in this setting. Objective: To define the role of bisoprolol, a highly selective beta(1)-antagonist in congestive heart failure due to systolic dysfunction....... Methods: Using the keywords 'bisoprolol' and 'heart failure' PubMed and BIOSIS databases were searched for information regarding pharmacology and relevant randomised clinical trials. Supplementary publications were acquired by scrutinising reference lists of relevant papers. Additional information...... was obtained from the FDA website. Conclusion: Bisoprolol is an effective and well-tolerated first-line beta-blocker for patients with systolic heart failure. The knowledge is primarily based on study patients with moderate-to-severe heart failure from the three CIBIS trials Udgivelsesdato: 2008/2...

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

Science.gov (United States)

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%.

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

Directory of Open Access Journals (Sweden)

Sanghyun Son

2015-08-01

Full Text Available 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%.

Characterizing the tradeoffs and costs associated with transportation congestion in supply chains.

Science.gov (United States)

2010-01-21

We consider distribution and location-planning models for supply chains that explicitly : account for traffic congestion effects. The majority of facility location and transportation : planning models in the operations research literature consider fa...

Reducing congestion and funding transportation using road pricing in Europe and Singapore

Science.gov (United States)

2010-12-01

Congestion pricing use has been limited in the United States because of political, institutional, and public acceptance concerns. The Federal Highway Administration, American Association of State Highway and Transportation Officials, and National Coo...

A case of congestive heart failure induced by therapeutic irradiation

International Nuclear Information System (INIS)

Kushigami, Motohiko; Suruda, Hidetoshi; Mizukoshi, Masato; Umemoto, Masaaki; Fujiwara, Setsuko; Yamamoto, Katsuhiro; Ueno, Yuji; Nishio, Ichiro; Masuyama, Yoshiaki

1985-01-01

Valvular insufficiency in radiation-induced heart disease is very rare. We described a patient, 53 years old woman, who developed congestive heart failure 2.5 years later following radiotherapy for esophageal carcinoma. The findings on examinations including cardiac catheterization revealed pericarditis with effusion, mitral and tricuspid valve insufficiency and pulmonary infarction. (author)

Urban emissions hotspots: Quantifying vehicle congestion and air pollution using mobile phone GPS data

International Nuclear Information System (INIS)

Gately, Conor K.; Hutyra, Lucy R.; Peterson, Scott; Sue Wing, Ian

2017-01-01

On-road emissions vary widely on time scales as short as minutes and length scales as short as tens of meters. Detailed data on emissions at these scales are a prerequisite to accurately quantifying ambient pollution concentrations and identifying hotspots of human exposure within urban areas. We construct a highly resolved inventory of hourly fluxes of CO, NO 2 , NO x , PM 2.5 and CO 2 from road vehicles on 280,000 road segments in eastern Massachusetts for the year 2012. Our inventory integrates a large database of hourly vehicle speeds derived from mobile phone and vehicle GPS data with multiple regional datasets of vehicle flows, fleet characteristics, and local meteorology. We quantify the ‘excess’ emissions from traffic congestion, finding modest congestion enhancement (3–6%) at regional scales, but hundreds of local hotspots with highly elevated annual emissions (up to 75% for individual roadways in key corridors). Congestion-driven reductions in vehicle fuel economy necessitated ‘excess’ consumption of 113 million gallons of motor fuel, worth ∼ $415M, but this accounted for only 3.5% of the total fuel consumed in Massachusetts, as over 80% of vehicle travel occurs in uncongested conditions. Across our study domain, emissions are highly spatially concentrated, with 70% of pollution originating from only 10% of the roads. The 2011 EPA National Emissions Inventory (NEI) understates our aggregate emissions of NO x , PM 2.5 , and CO 2 by 46%, 38%, and 18%, respectively. However, CO emissions agree within 5% for the two inventories, suggesting that the large biases in NO x and PM 2.5 emissions arise from differences in estimates of diesel vehicle activity. By providing fine-scale information on local emission hotspots and regional emissions patterns, our inventory framework supports targeted traffic interventions, transparent benchmarking, and improvements in overall urban air quality. - Highlights: • A high resolution, bottom-up inventory of

Design of Active Queue Management for Robust Control on Access Router for Heterogeneous Networks

Directory of Open Access Journals (Sweden)

Åhlund Christer

2011-01-01

Full Text Available The Internet architecture is a packet switching technology that allows dynamic sharing of bandwidth among different flows with in an IP network. Packets are stored and forwarded from one node to the next until reaching their destination. Major issues in this integration are congestion control and how to meet different quality of service requirements associated with various services. In other words streaming media quality degrades with increased packet delay and jitter caused by network congestion. To mitigate the impact of network congestion, various techniques have been used to improve multimedia quality and one of those techniques is Active Queue Management (AQM. Access routers require a buffer to hold packets during times of congestion. A large buffer can absorb the bursty arrivals, and this tends to increase the link utilizations but results in higher queuing delays. Traffic burstiness has a considerable negative impact on network performance. AQM is now considered an effective congestion control mechanism for enhancing transport protocol performance over wireless links. In order to have good link utilization, it is necessary for queues to adapt to varying traffic loads. This paper considers a particular scheme which is called Adaptive AQM (AAQM and studies its performance in the presence of feedback delays and its ability to maintain a small queue length as well as its robustness in the presence of traffic burstiness. The paper also presents a method based on the well-known Markov Modulated Poisson Process (MPP to capture traffic burstiness and buffer occupancy. To demonstrate the generality of the presented method, an analytic model is described and verified by extensive simulations of different adaptive AQM algorithms. The analysis and simulations show that AAQM outperforms the other AQMs with respect to responsiveness and robustness.

Xamoterol in severe congestive heart failure

DEFF Research Database (Denmark)

Tangø, M; Lyngborg, K; Mehlsen, J

1992-01-01

Twelve patients in severe congestive heart failure were given placebo, 100 mg xamoterol (Corwin) twice daily and 200 mg xamoterol twice daily, respectively, in 3 two-week periods in a double-blind randomised study. At the end of each treatment period the patients were evaluated. No differences were...... found between placebo and xamoterol in the following parameters: New York Heart Association function group index, heart volume, body weight, exercise duration on bicycle and treadmill, heart rate and systolic and diastolic blood pressure at rest. However, during exercise we found significantly lower...... heart rate and rate-pressure product during xamoterol treatment. This reduction is probably indicating occupation of beta-adrenoreceptors with concomitant reduced oxygen consumption during exercise....

"De-Randomizing" Congestion Losses to Improve TCP Performance over Wired-Wireless Networks

National Research Council Canada - National Science Library

Biaz, Saad; Vaidya, Nitin H

2004-01-01

.... This paper proposes a simple biased queue management scheme that "de-randomizes" congestion losses and enables a TCP receiver to diagnose accurately the cause of a loss and inform the TCP sender to react appropriately...

The asymptotic price of anarchy for k-uniform congestion games

NARCIS (Netherlands)

de Jong, Jasper; Kern, Walter; Steenhuisen, Berend; Uetz, Marc; Solis-Oba, Roberto

2018-01-01

We consider the atomic version of congestion games with affine cost functions, and analyze the quality of worst case Nash equilibria when the strategy spaces of the players are the set of bases of a k-uniform matroid. In this setting, for some parameter k, each player is to choose k out of a finite

Mammographic and sonographic findings of unilateral breast edema in congestive heart failure : a case report

Energy Technology Data Exchange (ETDEWEB)

Kim, Eun Kyung; Lee, Seung Koo; Oh, Ki Keun [Yonsei Univ. College of Medicine, Seoul (Korea, Republic of)

1997-06-01

Unilateral breast edema has many causes, though among these, congestive heart failure is rare. We report mammographic and sonographic findings of unilateral breast edema due to congestive heart failure. Mammography showed diffuse increase density and skin thickening but no evidence of mass or calcification. Ultrasonography showed skin thickening and increased echogenicity in the subcutaneous fat layer, while in the dermal layer, with tubular and reticular anechoic structures suggestive of dilated lymphatics were seen. After treatment of the heart failure, resolution of the abnormalities seen on mammogram established that these were secondary findings.

Mammographic and sonographic findings of unilateral breast edema in congestive heart failure : a case report

International Nuclear Information System (INIS)

Kim, Eun Kyung; Lee, Seung Koo; Oh, Ki Keun

1997-01-01

Unilateral breast edema has many causes, though among these, congestive heart failure is rare. We report mammographic and sonographic findings of unilateral breast edema due to congestive heart failure. Mammography showed diffuse increase density and skin thickening but no evidence of mass or calcification. Ultrasonography showed skin thickening and increased echogenicity in the subcutaneous fat layer, while in the dermal layer, with tubular and reticular anechoic structures suggestive of dilated lymphatics were seen. After treatment of the heart failure, resolution of the abnormalities seen on mammogram established that these were secondary findings

Integration of Electric Vehicles into the Power Distribution Network with a Modified Capacity Allocation Mechanism

Directory of Open Access Journals (Sweden)

Junjie Hu

2017-02-01

Full Text Available The growing penetration of electric vehicles (EVs represents an operational challenge to system operators, mainly at the distribution level by introducing congestion and voltage drop problems. To solve these potential problems, a two-level coordination approach is proposed in this study. An aggregation entity, i.e., an EV virtual power plant (EV-VPP, is used to facilitate the interaction between the distribution system operator (DSO and EV owners considering the decentralized electricity market structure. In level I, to prevent the line congestion and voltage drop problems, the EV-VPP internally respects the line and voltage constraints when making optimal charging schedules. In level II, to avoid power transformer congestion problems, this paper investigates three different coordination mechanisms, or power transformer capacity allocation mechanisms, between the DSO and the EV-VPPs, considering the case of EVs charging and discharging. The three mechanisms include: (1 a market-based approach; (2 a pro-rata approach; and (3 a newly-proposed constrained market-based approach. A case study considering a 37-bus distribution network and high penetration of electric vehicles is presented to demonstrate the effectiveness of the proposed coordination mechanism, comparing with the existing ones.

Transmission congestion management in the electricity market

Science.gov (United States)

Chen, Yue

2018-04-01

In this paper we mainly discuss how to optimize the arrangement to decrease the loss of each line when the power generation side of the system transmission congestion occurs in a safe and economical manner. We respectively set the adjust model if the transmission can be eliminated which can calculate the best scheme and safety margin model when transmission cannot be eliminated which is a multi-objective planning problem. We solve the two models on the condition of the load power demands are 982.4MW and 1052.8 MW by Lingo and get the optimal management scheme.

Speed Synchronization Control of Integrated Motor–Transmission Powertrain over CAN through Active Period-Scheduling Approach

Directory of Open Access Journals (Sweden)

Wanke Cao

2017-11-01

Full Text Available This paper deals with the speed synchronization control of integrated motor–transmission (IMT powertrain systems in pure electric vehicles (EVs over a controller area network (CAN subject to both network-induced delays and network congestion. A CAN has advantages over point-to-point communication; however, it imposes network-induced delays and network congestion into the control system, which can deteriorate the shifting quality and make system integration difficult. This paper presents a co-design scheme combining active period scheduling and discrete-time slip mode control (SMC to deal with both network-induced delays and network congestion of the CAN, which improves the speed synchronization control for high shifting quality and prevents network congestion for the system’s integration. The results of simulations and hardware-in-loop experiments show the effectiveness of the proposed scheme, which can ensure satisfactory speed synchronization performance while significantly reducing the network’s utilization.

New a priori estimates for mean-field games with congestion

KAUST Repository

Evangelista, David; Gomes, Diogo A.

2016-01-01

We present recent developments in crowd dynamics models (e.g. pedestrian flow problems). Our formulation is given by a mean-field game (MFG) with congestion. We start by reviewing earlier models and results. Next, we develop our model. We establish new a priori estimates that give partial regularity of the solutions. Finally, we discuss numerical results.

New a priori estimates for mean-field games with congestion

KAUST Repository

Evangelista, David

2016-01-06

We present recent developments in crowd dynamics models (e.g. pedestrian flow problems). Our formulation is given by a mean-field game (MFG) with congestion. We start by reviewing earlier models and results. Next, we develop our model. We establish new a priori estimates that give partial regularity of the solutions. Finally, we discuss numerical results.

Dynamic Control of Airport Departures: Algorithm Development and Field Evaluation

OpenAIRE

Simaiakis, Ioannis; Balakrishnan, Hamsa

2012-01-01

Surface congestion leads to significant increases in taxi times and fuel burn at major airports. In this paper, we formulate the airport surface congestion management problem as a dynamic control problem. We address two main challenges: the random delay between actuation (at the gate) and the server being controlled (the runway), and the need to develop control strategies that can be implemented in practice by human air traffic controllers. The second requirement necessitates a strategy that ...

Blood urea nitrogen to creatinine ratio is associated with congestion and mortality in heart failure patients with renal dysfunction.

Science.gov (United States)

Parrinello, Gaspare; Torres, Daniele; Testani, Jeffrey M; Almasio, Piero Luigi; Bellanca, Michele; Pizzo, Giuseppina; Cuttitta, Francesco; Pinto, Antonio; Butler, Javed; Paterna, Salvatore

2015-12-01

Renal dysfunction (RD) and venous congestion are related and common in heart failure (HF). Studies suggest that venous congestion may be the primary driver of RD in HF. In this study, we sought to investigate retrospectively the relationship between common measures of renal function with caval congestion and mortality among outpatients with HF and RD. We reviewed data from 103 HF outpatients (45 males, mean age 74 years, ejection fraction 41.8 ± 11.6 %) with estimated glomerular filtration rate (eGFR) of 25.5 (adjusted OR 2.98, p 0.015) and eGFR ≤ 45.8 (adjusted OR 5.38, p 0.002) identify patients at risk for caval congestion; a BUN/Cr > 23.7 was the best predictor of impaired collapsibility (adjusted OR 4.41, p 0.001). a BUN/Cr > 25.5 (HR 2.19, 95 % CI 1.21-3.94, p < 0.001) and NYHA class 3 (HR 2.91, 95 % CI 1.60-5.31, p < 0.0005) were independent risk factors associated with all-cause death during a median follow-up of 31 months. In outpatients with HF and RD, a higher BUN/Cr and lower eGFR are reliable renal biomarkers for caval congestion. The BUN/Cr is associated with long-term mortality and may help to stratify HF severity.

Computation of spot prices and congestion costs in large interconnected power systems

International Nuclear Information System (INIS)

Mukerji, R.; Jordan, G.A.; Clayton, R.; Haringa, G.E.

1995-01-01

Foremost among the new paradigms for the US utility industry is the ''poolco'' concept proposed by Prof. William W. Hogan of Harvard University. This concept uses a central pool or power exchange in which physical power is traded based on spot prices or market clearing prices. The rapid and accurate calculation of these ''spot'' prices and associated congestion costs for large interconnected power systems is the central tenet upon which the poolco concept is based. The market clearing price would be the same throughout the system if there were no system losses and transmission limitations did not exist. System losses cause small differences in market clearing prices as the cost of supplying a MW at various load buses includes the cost of losses. Transmission limits may cause large differences in market clearing prices between regions as low cost generation is blocked by the transmission constraints from serving certain loads. In models currently in use in the electric power industry spot price calculations range from ''bubble diagram'' type contract path models to full electrical representation such as GE-MAPS. The modeling aspects of the full electrical representation are included in the Appendix. The problem with the bubble diagram representation is that these models are liable to produce unacceptably large errors in the calculation of spot prices and congestion costs. The subtleties of the calculation of spot prices and congestion costs are illustrated in this paper

Successful microsurgical lip replantation: Monitoring venous congestion by blood glucose measurements in the replanted lip

Directory of Open Access Journals (Sweden)

Kazufumi Tachi

2018-03-01

Full Text Available Replantation of an amputated lip using microvascular anastomosis is the best option for restoration of the defect. However, the amputated region often lacks veins with appropriate diameters for microvascular anastomoses and typically necessitates both postoperative exsanguination using medicinal leeches and a blood transfusion. We present a case of the successful replantation of an avulsed lip in which postoperative congestion was evaluated objectively by measuring blood glucose levels in the replanted region. The patient presented to our hospital with an upper lip avulsion that was caused by a dog bite. The lip was replanted by the microvascular anastomoses of one artery and two veins using interposed vein grafts. The replanted lip showed signs of congestion on postoperative day one; exsanguination using medicinal leeches was attempted, while blood glucose levels were measured every three hours. Critical congestion, which did not occur in this patient, was defined as a blood glucose level lower than 40 mg/dL. Lip replantation was successful without any complications in this patient.

Acute Spinal Subdural Hematoma after Vertebroplasty: A Case Report Emphasizing the Possible Etiologic Role of Venous Congestion.

Science.gov (United States)

Mattei, Tobias A; Rehman, Azeem A; Dinh, Dzung H

2015-10-01

Study Design Case report and literature review. Objective Spinal subdural hematomas are rare events that often progress with severe neurologic deficits. Although there have been several case reports in the literature of spontaneous spinal subdural hematomas in the setting of anticoagulation, antiplatelet therapy, or coagulation disorders, the exact pathophysiology of such phenomena remains obscure. Methods We present the first report of a subdural hematoma after a percutaneous vertebroplasty and provide a comprehensive review on the anatomy of venous drainage of the vertebral bodies with emphasis on the possible effects of venous congestion caused by cement obstruction. Results Because the subdural hematoma occurred in the absence of major cement extravasation to the spinal canal and two levels above the site of the vertebroplasty, we discuss the possible role of venous congestion as the main etiologic factor leading to rupture of the fragile, valveless radiculomedullary veins into the subdural space. Conclusions The reported case supports a possible new pathophysiological scheme for the development of spinal subdural hematoma in which venous congestion plays a pivotal etiologic role. The reported findings suggests that future anatomical and histologic studies investigating the response of the radiculomedullary veins to congestive venous hypertension may shed new light into the pathophysiology of spinal subdural hematomas.

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

Directory of Open Access Journals (Sweden)

Prajakta Desai

Full Text Available 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.

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

Science.gov (United States)

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.

Diuretic treatment in decompensated cirrhosis and congestive heart failure: effect of posture

DEFF Research Database (Denmark)

Ring-Larsen, H; Henriksen, Jens Henrik Sahl; Wilken, C

1986-01-01

The diuretic effect of the supine position was evaluated in six patients with cirrhosis and ascites and six with congestive cardiac failure. After fasting overnight in bed the patients received bumetanide 1 mg intravenously and were then immediately randomly assigned to either bed rest in the sup......The diuretic effect of the supine position was evaluated in six patients with cirrhosis and ascites and six with congestive cardiac failure. After fasting overnight in bed the patients received bumetanide 1 mg intravenously and were then immediately randomly assigned to either bed rest...... in the supine position or normal daily activity in the upright position for the next six hours. Two days later the procedure was repeated, the patients being assigned to the other posture. The diuretic response was similar in patients with heart failure and cirrhosis, and was significantly greater in the supine...

Research on Capacity Addition using Market Model with Transmission Congestion under Competitive Environment

Science.gov (United States)

Katsura, Yasufumi; Attaviriyanupap, Pathom; Kataoka, Yoshihiko

In this research, the fundamental premises for deregulation of the electric power industry are reevaluated. The authors develop a simple model to represent wholesale electricity market with highly congested network. The model is developed by simplifying the power system and market in New York ISO based on available data of New York ISO in 2004 with some estimation. Based on the developed model and construction cost data from the past, the economic impact of transmission line addition on market participants and the impact of deregulation on power plant additions under market with transmission congestion are studied. Simulation results show that the market signals may fail to facilitate proper capacity additions and results in the undesirable over-construction and insufficient-construction cycle of capacity addition.

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

Science.gov (United States)

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.

Publicly announced access recommendations and consumers’ service time choices with uncertain congestion

NARCIS (Netherlands)

Han, Q.; Benedict, G.C.; Dellaert, W.; van Raaij, W.F.; Timmermans, H.J.P.

2014-01-01

This article investigates consumers' anticipation of other consumers' service time choices in capacity-constrained services and how this is affected by publicly announced access recommendations. Empirical results from an experiment with simulated congestion experiences show that the impact of

Publicly announced access recommendations and consumers' service time choices with uncertain congestion

NARCIS (Netherlands)

Han, Q.; Dellaert, B.G.C.; Raaij, W.F.V.; Timmermans, H.J.P.

2014-01-01

This article investigates consumers' anticipation of other consumers' service time choices in capacity-constrained services and how this is affected by publicly announced access recommendations. Empirical results from an experiment with simulated congestion experiences show that the impact of

Transport growth in Bangkok: Energy, environment, and traffic congestion. Workshop proceedings

Energy Technology Data Exchange (ETDEWEB)

Philpott, J. [Asia Regional Office, Bangkok (Thailand)

1995-07-01

Bangkok, the capital of Thailand, is a physically and economically complexcity with a complicated transport system. With daily traffic congestion averaging 16 hours, the air quality is such that to breathe street level pollution for 8 eight hours is roughly equivalent to smoking nine cigarettes per day. Estimates suggest idling traffic costs up to $1.6 billion annually. Energy use within the transport sector is on a steady rise with an estimated increase in 11 years of two and one half times. Severe health impacts have begun to effect many residents - young children and the elderly being particularly vulnerable. Bangkok`s air quality and congestion problems are far from hopeless. Great potential exists for Bangkok to remedy its transport-related problems. The city has many necessary characteristics that allow an efficient, economical system of transport. For example, its high density level makes the city a prime candidate for an efficient system of mass transit and the multitude and close proximity of shops, street vendors, restaurants, and residential areas is highly conducive to walking and cycling. Technical knowledge and capacity to devise and implement innovative policies and projects to address air quality and congestion problems is plentiful. There is also consensus among Bangkokians that something needs to be done immediately to clear the air and the roads. However, little has been done. This report proposes a new approach to transport planning for Bangkok that integrates consideration of ecological, social, and financial viability in the process of making decisions regarding managing existing infrastructure and investments in new infrastructure. Selected papers have been indexed separately for inclusion in the Energy Science and Technology Database.

Parametric study of control mechanism of cortical bone remodeling under mechanical stimulus

Science.gov (United States)

Wang, Yanan; Qin, Qing-Hua

2010-03-01

The control mechanism of mechanical bone remodeling at cellular level was investigated by means of an extensive parametric study on a theoretical model described in this paper. From a perspective of control mechanism, it was found that there are several control mechanisms working simultaneously in bone remodeling which is a complex process. Typically, an extensive parametric study was carried out for investigating model parameter space related to cell differentiation and apoptosis which can describe the fundamental cell lineage behaviors. After analyzing all the combinations of 728 permutations in six model parameters, we have identified a small number of parameter combinations that can lead to physiologically realistic responses which are similar to theoretically idealized physiological responses. The results presented in the work enhanced our understanding on mechanical bone remodeling and the identified control mechanisms can help researchers to develop combined pharmacological-mechanical therapies to treat bone loss diseases such as osteoporosis.

Measuring outcomes in allergic rhinitis: psychometric characteristics of a Spanish version of the congestion quantifier seven-item test (CQ7

Directory of Open Access Journals (Sweden)

Mullol Joaquim

2011-03-01

Full Text Available Abstract Background No control tools for nasal congestion (NC are currently available in Spanish. This study aimed to adapt and validate the Congestion Quantifier Seven Item Test (CQ7 for Spain. Methods CQ7 was adapted from English following international guidelines. The instrument was validated in an observational, prospective study in allergic rhinitis patients with NC (N = 166 and a control group without NC (N = 35. Participants completed the CQ7, MOS sleep questionnaire, and a measure of psychological well-being (PGWBI. Clinical data included NC severity rating, acoustic rhinometry, and total symptom score (TSS. Internal consistency was assessed using Cronbach's alpha and test-retest reliability using the intraclass correlation coefficient (ICC. Construct validity was tested by examining correlations with other outcome measures and ability to discriminate between groups classified by NC severity. Sensitivity and specificity were assessed using Area under the Receiver Operating Curve (AUC and responsiveness over time using effect sizes (ES. Results Cronbach's alpha for the CQ7 was 0.92, and the ICC was 0.81, indicating good reliability. CQ7 correlated most strongly with the TSS (r = 0.60, p Conclusions The Spanish version of the CQ7 is appropriate for detecting, measuring, and monitoring NC in allergic rhinitis patients.

Liver Function in Areas of Hepatic Venous Congestion After Hepatectomy for Liver Cancer: 99mTc-GSA SPECT/CT Fused Imaging Study.

Science.gov (United States)

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 (pliver 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.

Effect of diosmin on chronic nonbacterial prostatitis caused by pelvic congestion in rats

Directory of Open Access Journals (Sweden)

Gong-ting CUI

2014-08-01

Full Text Available Objective　To explore the effect of diosmin on chronic nonbacterial prostatitis (CNP in rats and its possible mechanisms. Methods　Thirty-two healthy adult male SD rats were randomly divided into 4 groups: Sham-operated group (SO group, chronic prostatitis model group (CPM group, chronic prostatitis model + prostat treatment group (CPM-P group, and chronic prostatitis model + diosmin treatment group (CPM-D group. Rats in SO group underwent laparotomy only to expose the prostate, and those in other groups received prostatic vein ligation to reproduce pelvic congestion. HE staining was used for the examination of the prostate 35 days after the operation. 80mg/(kg.d of diosmin was given to the rats in CPM-D group, and 60mg/(kg.d of diosmin to the rats in CPM-P group twice a day by gavage for 7 days. Same volume of 5% acacia gum was given to rats in SO and CPM groups. All of the rats were sacrificed 1h after the last administration, and the serum levels of interleukin-10 (IL-10, IL-8, IL-1β, malondialdehyde (MDA, nitric oxide (NO were determined by ELISA, and the pathological changes in the prostate tissue were observed after HE staining and compared between the groups. Results　The serum levels of IL-1β, IL-8 and NO were significantly lower in CPM-D group and CPM-P group than in CPM group (P<0.05, the serum level of IL-10 was significantly higher in CPM-D group and CPM-P group than in CPM group (P<0.05, and the serum MDA level was similar between the 3 groups. HE staining showed that chronic inflammatory changes in rats' prostate were reduced more significantly in CPM-P group and CPM-D group than in CPM group. Conclusion　The therapeutic effect of diosmin on pelvic-congestion-induced chronic prostatitis is similar to that of prostat tablets, and its mechanism may be related to the alleviation of local inflammatory response by reducing the IL-1β, IL-8 and NO levels and increasing the IL-10 content in serum. DOI: 10.11855/j.issn.0577-7402.2014.06.04

Traffic conflict assessment for non-lane-based movements of motorcycles under congested conditions

Directory of Open Access Journals (Sweden)

Long Xuan Nguyen

2014-03-01

Full Text Available Traffic conflict under congested conditions is one of the main safety issues of motorcycle traffic in developing countries. Unlike cars, motorcycles often display non-lane-based movements such as swerving or oblique following of a lead vehicle when traffic becomes congested. Very few studies have quantitatively evaluated the effects of such non-lane-based movements on traffic conflict. Therefore, in this study we aim to develop an integrated model to assess the traffic conflict of motorcycles under congested conditions. The proposed model includes a concept of safety space to describe the non-lane-based movements unique to motorcycles, new features developed for traffic conflict assessment such as parameters of acceleration and deceleration, and the conditions for choosing a lead vehicle. Calibration data were extracted from video clips taken at two road segments in Ho Chi Minh City. A simulation based on the model was developed to verify the dynamic non-lane-based movements of motorcycles. Subsequently, the assessment of traffic conflict was validated by calculating the probability of sudden braking at each time interval according to the change in the density of motorcycle flow. Our findings underscore the fact that higher flow density may lead to conflicts associated with a greater probability of sudden breaking. Three types of motorcycle traffic conflicts were confirmed, and the proportions of each type were calculated and discussed.

Effect of the nasal cycle on congestive response during bilateral nasal allergen provocation

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Tomasz Gotlib

2014-06-01

Full Text Available Background. Bilateral nasal allergen provocation usually produces more pronounced obstruction of one nasal passage. It was found that this could be related to the stage of the nasal cycle before the provocation. objective. To discover whether the stage of the nasal cycle is decisive for asymmetry in congestive response observed during bilateral allergen nasal provocation. methods. Two bilateral nasal allergen provocations were performed in a group of 26 pollen-sensitive volunteers. Acoustic rhinometry measurements were taken during the nasal cycle, and then after the provocation. A cross-sectional area at the level of the inferior turbinate (CSA-2 was measured. Consecutive challenges were performed in the opposite phase of the nasal cycle: the side which had been wide just before the first challenge, was narrow before the second provocation. results. Asymmetry in CSA-2 reduction between the nasal passages was observed in most cases. Significant difference was observed between mean CSA-2 reduction rate (reactivity of the side that responded with greater congestion, and the opposite side. No significant difference was found in mean CSA-2 reduction rate between the side which was narrow, and the side which was wide before provocation. conclusions. Asymmetry of congestive response during bilateral nasal allergen provocation is not dependent on the stage of the nasal cycle preceding the challenge.

Political and Public Acceptability of Congestion Pricing: Ideology and Self-Interest

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Harsman, Bjorn; Quigley, John M.

2010-01-01

Studies of the "stated preferences" of households generally report public and political opposition by urban commuters to congestion pricing. It is thought that this opposition inhibits or precludes tolls and pricing systems that would enhance efficiency in the use of scarce roadways. This paper analyzes the only case in which road…

Direct Open Venous Drainage: An Alternative Choice for Flap Congestion Salvage.

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Park, Su Han; Choi, Woo Young; Son, Kyung Min; Cheon, Ji Seon; Yang, Jeong Yeol

2015-12-01

In this report, we present a scalp defect reconstruction with lateral arm free flap. We highlight the difficulty in obtaining a recipient vein and the venous drainage managed through an open end of the donor vein. A 52-year-old woman presented with a pressure sore on the left scalp. A lateral arm free flap was transferred to cover this 8×6 cm defect. The arterial anastomosis was successful, but no recipient vein could be identified within the wound bed. Instead, we used a donor venous end for the direct open venous drainage. In order to keep this exposed venous end patent, we applied heparin-soaked gauze dressing to the wound. Also, the vein end was mechanically dilated and irrigated with heparin solution at two hour intervals. Along with fluid management and blood transfusion, this management was continued for the five days after the operation. The flap survived well without any complication. Through this case, we were able to demonstrate that venous congestion can be avoided by drainage of the venous blood through an open vessel without the use of leeches.

MAINTAINING VEHICLE SPEED USING A MECHANICAL CRUISE CONTROL

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Peter GIROVSKÝ

2017-06-01

Full Text Available In this article we would like to present cruise control realization. This cruise control is presented as mechanical device for vehicle speed maintenance and has been proposed as a low cost solution. Principle of function in mechanical cruise control is based on a position control of throttle. For the right action of mechanical cruise control it was need to solve some particular tasks related with speed sensing, construct of device for control of throttle position and design of control system of whole mechanical cruise control. Information about car velocity we have gained using Hall sensor attached on a magnetic ring of car tachometer. For control of the throttle was used a small servo drive and as the control unit was used Arduino. The designed solution of mechanical cruise control have been realized for car Škoda Felicia.

Natriuretic Peptides as Biomarkers for Congestive States: The Cardiorenal Divergence

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Abhilash Koratala

2017-01-01

Full Text Available Congestion represents the primary reason for hospitalization of patients with heart failure and is associated with adverse outcomes. Fluid overload has been shown to be inadequately addressed in a significant subset of these patients in part due to lack of robust, reliable, and readily available biomarkers for objective assessment and monitoring of therapy. Natriuretic peptides have long been used in this setting, often in conjunction with other assessment tools such as imaging studies. Patients presenting with concomitant cardiac and renal dysfunction represent a unique population with regard to congestion in that the interactions between the heart and the kidney can affect the utility and performance of biomarkers of fluid overload. Herein, we provide an overview of the currently available evidence on the utility of natriuretic peptides in these patients and discuss the clinical conundrum associated with their use in the setting of renal dysfunction. We highlight the potential divergence in the role of natriuretic peptides for assessment of volume status in a subset of patients with renal dysfunction who receive renal replacement therapy and call for future research to elucidate the utility of the biomarkers in this setting.

FLECH - A Danish market solution for DSO congestion management through DER flexibility services

DEFF Research Database (Denmark)

Zhang, Chunyu; Ding, Yi; Nordentoft, Niels Christian

2014-01-01

Future electric power systems will face new operational challenges due to the high penetration of distributed energy resources (DERs). In Denmark distribution system operator (DSO) expects a significant congestion increased in distribution grids. In order to manage these congestions and mobilize...... the DERs as economically efficient as possible in the future distribution grid, the brand new notion of Flexibility Clearing House (FLECH) is proposed in this paper. With the Aggregator-based offers, the proposed FLECH market has the ability to promote small scale DERs (up to 5MW) for actively...... participating in trading flexibility services, which are stipulated accommodating the various requirements of DSO. Accordingly, the trading setups and processes of the FLECH market are also illustrated in detail. A quantitative example is utilized to illustrate the formulation and classification of flexibility...

The dynamics of urban traffic congestion and the price of parking

DEFF Research Database (Denmark)

Fosgerau, Mogens; de Palma, André

2013-01-01

We consider commuting in a congested urban area. While an efficient time-varying toll may eliminate queuing, a toll may not be politically feasible. We study the benefit of a substitute: a parking fee at the workplace. An optimal time-varying parking fee is charged at zero rate when there is queu...

Control mechanisms in franchise systems

OpenAIRE

Hass, Jörg

2012-01-01

This dissertation answers the question which different control mechanisms exist in a franchise system. It is the first two-sided franchise empirical analysis, regarding all outlets of the franchise system (franchisees and company-owned) as well as the franchisor. On the theoretical side, this dissertation integrates the two main management theories: principal-agent-theory and transaction cost analysis. The results show that there are used different control mechanisms in a franchise sys...

Real Time Emulation of Dynamic Tariff for Congestion Management in Distribution Networks

DEFF Research Database (Denmark)

Rasmussen, Theis Bo; Wu, Qiuwei; Huang, Shaojun

2016-01-01

This paper presents the real time evaluation of the dynamic tariff (DT) method for alleviating congestion in a distribution networks with high penetration of distributed energy resources (DERs). The DT method is implemented in a real time digital testing platform that emulates a real distribution...

Renal function in patients with hypertension associated congestive cardiac failure seen in a tertiary hospital.

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Osuji, C U; Nwaneli, C U; Onwubere, B J; Onwubuya, E I; Ahaneku, G I

2012-01-01

Background. Chronic kidney disease is frequently seen in patients with congestive cardiac failure and is an independent risk factor for morbidity and mortality. The aim of this study was to determine the prevalence of chronic kidney disease in patients with hypertension associated congestive cardiac failure. Method. One hundred and fifty patients with hypertension associated congestive cardiac failure were recruited consecutively from the medical outpatient department and the medical wards of the Nnamdi Azikiwe University Teaching Hospital Nnewi over a one year period, January to December 2010. Patients' biodata and medical history were obtained, detailed physical examination done and each patient had a chest X-ray, 12 lead ECG, urinalysis, serum urea and creatinine assay done. Ethical clearance was obtained from the Ethical Review Board of our institution and data analysed using SPSS-version 16. Results. There were 86 males and 64 females with mean age 62.7 ± 12.5 years. The mean blood pressures were systolic 152.8 ± 28.5 mmHg and diastolic 94.3 ± 18 mmHg. 84.7% had blood pressure ≥140/90 mmHg on presentation. The mean GFR was 70.1 ± 31.3 mls/min. 76% of subjects had GFR <90 mls/min and no statistical significant difference between males and females, P = 0.344. The mean serum urea was 7.2 ± 51 mmol/L while the mean serum creatinine was 194 ± 416.2 mmol/L. Conclusions. This study has demonstrated that majority of patients presenting with hypertension associated congestive cardiac failure have some degree of chronic kidney disease.

Occurrence, aetiology and challenges in the management of congestive heart failure in sub-saharan Africa: experience of the Cardiac Centre in Shisong, Cameroon

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Tantchou Tchoumi Jacques Cabral

2011-02-01

Full Text Available INTRODUCTION: The aim of the study was to investigate the occurrence, the aetiology and the management of congestive heart failure in the cardiac centre of the St. Elizabeth catholic general hospital Shisong in Cameroon. METHODS: Between November 2002 and November 2008, a population of 8121 patients was consulted in the referral cardiac centre of St. Elizabeth Catholic General Hospital. Of these patients, 462 were diagnosed with congestive heart failure according to the modified Framingham criteria for the diagnosis of heart failure. Complementary investigations used to confirm and establish the aetiology of the disease were the chest X-ray, electrocardiography, bi-dimensional Doppler echocardiography. RESULTS: The results showed that the occurrence of congestive heart failure in our centre was 5,7%. Congestive heart failure was diagnosed in 198 females and 264 males, aged between 8 and 86 years old (42.5, plus or minus 18 years old. Post rheumatic valvulopathies (14.6% and congenital heart diseases (1.9% were the first aetiologic factor of congestive heart failure in the young, meanwhile cardiomyopathies (8,3% in elderly followed by hypertensive cardiomyopathy (4.4%. Congestive heart failure was also seen in adults with congenital heart diseases in 0.01%. In this zone of Cameroon, we discovered that HIV cardiomyopathy (1.6% and Cor pulmonale (8% were represented, aetiological factors not mentioned in previous studies conducted in urban areas of Cameroon. The mean duration of hospital stay for the compensation treatment was thirteen days, ranging between 7 and 21 days, the mortality being 9.2%. All the medications recommended for the treatment of congestive heart failure are available in our centre but many patients are not compliant to the therapy or cannot afford them. Financial limitation is causing the exacerbation of the disease and premature death. CONCLUSION: Our data show a high incidence of congestive heart failure mainly due to post

Explicit solutions of one-dimensional, first-order, stationary mean-field games with congestion

KAUST Repository

Gomes, Diogo A.; Nurbekyan, Levon; Prazeres, Mariana

2017-01-01

Here, we consider one-dimensional first-order stationary mean-field games with congestion. These games arise when crowds face difficulty moving in high-density regions. We look at both monotone decreasing and increasing interactions and construct

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

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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.

Application of Adaptive Starling-Like Controller to Total Artificial Heart Using Dual Rotary Blood Pumps.

Science.gov (United States)

Ng, Boon C; Smith, Peter A; Nestler, Frank; Timms, Daniel; Cohn, William E; Lim, Einly