Impact of introducing longer and heavier vehicles on regional consumer price index and Spanish road freight transport system

This paper applies an integrated modeling approach to the case of Spain; the approach is based on a random utility-based multiregional input-output model and a road transport network model for assessing the effect of introducing longer and heavier vehicles (LHVs) on the regional consumer price index (CPI) and on the transportation system. The approach strongly supports the concept that changes in transport costs derived from the LHV allowance as well as the economic structure of regions have direct and indirect effects on the economy and on the transportation system. Results show that the introduction of LHVs might reduce prices paid by consumers for a representative basket of goods and services in the regions of Spain and would also lead to a reduction in the regional CPI. In addition, the magnitude and extent of changes in the transportation system are estimated by using the commodity-based structure of the approach to identify the effect of traffic changes on traffic flows and on pollutant emissions over the whole network.

An integrated modeling approach to assess the impact on road freight transport demand of allowing longer and heavier vehicles (LHVs) in Spain

The assessment on introducing Longer and Heavier Vehicles (LHVs) on the road freight transport demand is performed in this paper by applying an integrated modeling approach composed of a Random Utility-Based Multiregional Input-Output model (RUBMRIO) and a road transport network model. The approach strongly supports the concept that changes in transport costs derived from the LHVs allowance as well as the economic structure of regions have both direct and indirect effects on the road freight transport system. In addition, we estimate the magnitude and extent of demand changes in the road freight transportation system by using the commodity-based structure of the approach to identify the effect on traffic flows and on pollutant emissions over the whole network of Spain by considering a sensitivity analysis of the main parameters which determine the share of Heavy-Goods Vehicles (HGVs) and LHVs. The results show that the introduction of LHVs will strengthen the competitiveness of the road haulage sector by reducing costs, emissions, and the total freight vehicles required.

Assessment methodology to make urban transport interchanges attractive for users

En las ciudades europeas, los patrones de movilidad son cada vez más complejos debido fundamentalmente a un crecimiento sostenido de la población así como a la tendencia de dispersión de los núcleos urbanos. En consecuencia, muchos de los usuarios del transporte público se ven obligados a combinar varios modos o servicios de transporte para completar sus viajes diarios. Por tanto, el mayor reto de las ciudades es conseguir una mejora e incremento en la movilidad mientras que al mismo tiempo se reducen problemas como la congestión, los accidentes y la contaminación (COM, 2006). Un principio básico para lograr una movilidad sostenible es reducir los inconvenientes y molestias derivados de la transferencia o ruptura del viaje. En este sentido, los intercambiadores de transporte público juegan un papel fundamental como nodos de la red urbana de transporte y la calidad del servicio prestado en ellos tiene una influencia directa sobre la experiencia diaria de los viajeros. Como señaló Terzis and Last (2002), un intercambiador de transportes urbano eficiente debe ser competitivo y al mismo tiempo, debe ser atractivo para los usuarios dado que sus experiencias físicas y sus reacciones psicológicas se ven influenciadas de manera significativa por el diseño y operación del intercambiador. Sin embargo, todavía no existen standards o normativas a nivel europeo que especifiquen como deberían ser estos intercambiadores. Esta tesis doctoral proporciona conocimientos y herramientas de análisis dirigidas a planificadores y gestores de los propios intercambiadores con el fin de entender mejor el funcionamiento de los intercambiadores y gestionar así los recursos disponibles. Así mismo, esta tesis identifica los factores clave en el diseño y operación de intercambiadores urbanos de transporte y proporciona algunas guías generales de planificación en base a ellos. Dado que las percepciones de los usuarios son particularmente importantes para definir políticas adecuadas para intercambiadores, se diseñó y se llevó a cabo en 2013 una encuesta de satisfacción al viajero en tres intercambiadores de transporte urbano europeos: Moncloa (Madrid, España), Kamppi (Helsinki, Finlandia) e Ilford Railway Station ( Londres, Reino Unido). En resumen, esta tesis pone de relieve la naturaleza ambivalente de los intercambiadores urbanos de transporte, es decir, como nodos de la red de transporte y como lugares en sí mismos donde los usuarios pasan tiempo dentro de ellos y propone algunas recomendaciones para hacer más atractivos los intercambiadores a los usuarios. Travel patterns in European urban areas are becoming increasingly complex due to a sustained increase in the urban population and the trend towards urban sprawl. Consequently, many public transport users need to combine several modes or transport services to complete their daily trips. Therefore, the challenge facing all major cities is how to increase mobility while at the same time reducing congestion, accididents and pollution (COM, 2006). Reducing the inconvenience inherent in transferring between modes is a basic principle for achieving sustainable mobility. In this regard, transport interchanges play a key role as urban transport network nodes, and the quality of the service provided in them has a direct influence on travellers' daily experience. As noted by Terzis and Last (2000), an efficient urban transport interchange must be competitive and, at the same time, be attractive for users given that their physical experiences and psychological reactions are significantly influenced by the design and operation of the interchange. However, yet there are no standards or regulations specifying the form these interchanges should take in Europe. This doctoral thesis provides knowledge and analysis tools addressed to developers and managers in order to understand better the performance of an urban transport interchange and manage the available resources properly. Likewise, key factors of the design and operation of urban transport interchanges are identified and some 'Planning guidelines' are proposed on the basis on them. Since the users' perceptions of their experience are particularly important for achieving the most appropriate policy measures for interchanges, an ad‐hoc travellers' satisfaction survey was designed and carried out in 2013 at three European transport interchanges: Moncloa (Madrid, Spain), Kamppi (Helsinki, Finland) and Ilford Railway Station (London, United Kingdom) In summary, this thesis highlights the ambivalent nature of the urban transport interchanges, i.e. as nodes within the transport network and as places where users spending time and proposes some policy recommendations in order to make urban transport interchanges attractive for users.

Algoritmos de decisión para priorizar las acciones de restauración en el mantenimiento de redes

En la actualidad, cualquier compañía de telecomunicaciones que posea su propia red debe afrontar el problema del mantenimiento de la misma. Ofrecer un mínimo de calidad de servicio a sus clientes debe ser uno de sus objetivos principales. Esta calidad debe mantenerse aunque ocurran incidencias en la red. El presente trabajo pretende resolver el problema de priorizar el orden en que se restauran los cables, caminos y circuitos, dañados por una incidencia, dentro de una red troncal de transporte perteneciente a una operadora de telecomunicaciones. Tras un planteamiento detallado del problema y de todos los factores que influirán en la toma de decisión, en primer lugar se acomete una solución basada en Métodos Multicriterio Discretos, concretamente con el uso de ELECTRE I y AHP. A continuación se realiza una propuesta de solución basada en Redes Neuronales (con dos aproximaciones diferentes al problema). Por último se utiliza un método basado en la Optimización por Enjambre de Partículas (PSO), adaptado a un problema de permutación de enteros (ordenación), y con una forma particular de evaluar la mejor posición global del enjambre. Complementariamente se realiza una exposición de lo que es una empresa Operadora de telecomunicaciones, de sus departamentos y procesos internos, de los servicios que ofrece, de las redes sobre las que se soportan, y de los puntos clave a tener en cuenta en la implementación de sus sistemas informáticos de gestión integral. ABSTRACT: Nowadays, any telecommunications company that owns its own network must face the problem of maintaining it (service assurance). Provide a minimum quality of service to its customers must be one of its main objectives. This quality should be maintained although any incidents happen to occur in the network. This thesis aims to solve the problem of prioritizing the order in which the damaged cables, trails, path and circuits, within a backbone transport network, should be restored. This work begins with a detailed explanation about network maintenance issues and all the factors that influence decision-making problem. First of all, one solution based on Discrete Multicriteria methods is tried (ELECTRE I and AHP algorithms are used). Also, a solution based on neural networks (with two different approaches to the problem) is analyzed. Finally, this thesis proposes an algorithm based on Particle Swarm Optimization (PSO), adapted to a problem of integers permutation, and a particular way of evaluating the best overall position of the swarm method. In addition, there is included an exhibition about telecommunications companies, its departments, internal processes, services offered to clients, physical networks, and key points to consider when implementing its integrated management systems.

Optimization of ATM Telecommunication Networks

ATM network optimization problems defined as combinatorial optimization problems are considered. Several approximate algorithms for solving such problems are developed. Results of their comparison by experiments on a set of problems with random input data are presented.

Resource management and optimization in wireless mesh networks

A wireless mesh network is a mesh network implemented over a wireless network system such as wireless LANs. Wireless Mesh Networks(WMNs) are promising for numerous applications such as broadband home networking, enterprise networking, transportation systems, health and medical systems, security surveillance systems, etc. Therefore, it has received considerable attention from both industrial and academic researchers. This dissertation explores schemes for resource management and optimization in WMNs by means of network routing and network coding.^ In this dissertation, we propose three optimization schemes. (1) First, a triple-tier optimization scheme is proposed for load balancing objective. The first tier mechanism achieves long-term routing optimization, and the second tier mechanism, using the optimization results obtained from the first tier mechanism, performs the short-term adaptation to deal with the impact of dynamic channel conditions. A greedy sub-channel allocation algorithm is developed as the third tier optimization scheme to further reduce the congestion level in the network. We conduct thorough theoretical analysis to show the correctness of our design and give the properties of our scheme. (2) Then, a Relay-Aided Network Coding scheme called RANC is proposed to improve the performance gain of network coding by exploiting the physical layer multi-rate capability in WMNs. We conduct rigorous analysis to find the design principles and study the tradeoff in the performance gain of RANC. Based on the analytical results, we provide a practical solution by decomposing the original design problem into two sub-problems, flow partition problem and scheduling problem. (3) Lastly, a joint optimization scheme of the routing in the network layer and network coding-aware scheduling in the MAC layer is introduced. We formulate the network optimization problem and exploit the structure of the problem via dual decomposition. We find that the original problem is composed of two problems, routing problem in the network layer and scheduling problem in the MAC layer. These two sub-problems are coupled through the link capacities. We solve the routing problem by two different adaptive routing algorithms. We then provide a distributed coding-aware scheduling algorithm. According to corresponding experiment results, the proposed schemes can significantly improve network performance.^

Host and network optimizations for performance enhancement and energy efficiency in data center networks

Modern data centers host hundreds of thousands of servers to achieve economies of scale. Such a huge number of servers create challenges for the data center network (DCN) to provide proportionally large bandwidth. In addition, the deployment of virtual machines (VMs) in data centers raises the requirements for efficient resource allocation and find-grained resource sharing. Further, the large number of servers and switches in the data center consume significant amounts of energy. Even though servers become more energy efficient with various energy saving techniques, DCN still accounts for 20% to 50% of the energy consumed by the entire data center. The objective of this dissertation is to enhance DCN performance as well as its energy efficiency by conducting optimizations on both host and network sides. First, as the DCN demands huge bisection bandwidth to interconnect all the servers, we propose a parallel packet switch (PPS) architecture that directly processes variable length packets without segmentation-and-reassembly (SAR). The proposed PPS achieves large bandwidth by combining switching capacities of multiple fabrics, and it further improves the switch throughput by avoiding padding bits in SAR. Second, since certain resource demands of the VM are bursty and demonstrate stochastic nature, to satisfy both deterministic and stochastic demands in VM placement, we propose the Max-Min Multidimensional Stochastic Bin Packing (M3SBP) algorithm. M3SBP calculates an equivalent deterministic value for the stochastic demands, and maximizes the minimum resource utilization ratio of each server. Third, to provide necessary traffic isolation for VMs that share the same physical network adapter, we propose the Flow-level Bandwidth Provisioning (FBP) algorithm. By reducing the flow scheduling problem to multiple stages of packet queuing problems, FBP guarantees the provisioned bandwidth and delay performance for each flow. Finally, while DCNs are typically provisioned with full bisection bandwidth, DCN traffic demonstrates fluctuating patterns, we propose a joint host-network optimization scheme to enhance the energy efficiency of DCNs during off-peak traffic hours. The proposed scheme utilizes a unified representation method that converts the VM placement problem to a routing problem and employs depth-first and best-fit search to find efficient paths for flows.

Optimization of a multielectrode array (MEA)-based approach to study the impact of Aβ on the SH-SY5Y cell line

The human brain stores, integrates, and transmits information recurring to millions of neurons, interconnected by countless synapses. Though neurons communicate through chemical signaling, information is coded and conducted in the form of electrical signals. Neuroelectrophysiology focus on the study of this type of signaling. Both intra and extracellular approaches are used in research, but none holds as much potential in high-throughput screening and drug discovery, as extracellular recordings using multielectrode arrays (MEAs). MEAs measure neuronal activity, both in vitro and in vivo. Their key advantage is the capability to record electrical activity at multiple sites simultaneously. Alzheimer’s disease (AD) is the most common neurodegenerative disease and one of the leading causes of death worldwide. It is characterized by neurofibrillar tangles and aggregates of amyloid-β (Aβ) peptides, which lead to the loss of synapses and ultimately neuronal death. Currently, there is no cure and the drugs available can only delay its progression. In vitro MEA assays enable rapid screening of neuroprotective and neuroharming compounds. Therefore, MEA recordings are of great use in both AD basic and clinical research. The main aim of this thesis was to optimize the formation of SH-SY5Y neuronal networks on MEAs. These can be extremely useful for facilities that do not have access to primary neuronal cultures, but can also save resources and facilitate obtaining faster high-throughput results to those that do. Adhesion-mediating compounds proved to impact cell morphology, viability and exhibition of spontaneous electrical activity. Moreover, SH-SY5Y cells were successfully differentiated and demonstrated acute effects on neuronal function after Aβ addition. This effect on electrical signaling was dependent on Aβ oligomers concentration. The results here presented allow us to conclude that the SH-SY5Y cell line can be successfully differentiated in properly coated MEAs and be used for assessing acute Aβ effects on neuronal signaling.

Defining the Resolution of a Network for Transportation Analyses: a New Method to Improve Transportation Planning Decisions

Travel demand models are important tools used in the analysis of transportation plans, projects, and policies. The modeling results are useful for transportation planners making transportation decisions and for policy makers developing transportation policies. Defining the level of detail (i.e., the number of roads) of the transport network in consistency with the travel demand model’s zone system is crucial to the accuracy of modeling results. However, travel demand modelers have not had tools to determine how much detail is needed in a transport network for a travel demand model. This dissertation seeks to fill this knowledge gap by (1) providing methodology to define an appropriate level of detail for a transport network in a given travel demand model; (2) implementing this methodology in a travel demand model in the Baltimore area; and (3) identifying how this methodology improves the modeling accuracy. All analyses identify the spatial resolution of the transport network has great impacts on the modeling results. For example, when compared to the observed traffic data, a very detailed network underestimates traffic congestion in the Baltimore area, while a network developed by this dissertation provides a more accurate modeling result of the traffic conditions. Through the evaluation of the impacts a new transportation project has on both networks, the differences in their analysis results point out the importance of having an appropriate level of network detail for making improved planning decisions. The results corroborate a suggested guideline concerning the development of a transport network in consistency with the travel demand model’s zone system. To conclude this dissertation, limitations are identified in data sources and methodology, based on which a plan of future studies is laid out.

Developing strategies to mitigate the energy consumed by network infrastructures

The energy consumption by ICT (Information and Communication Technology) equipment is rapidly increasing which causes a significant economic and environmental problem. At present, the network infrastructure is becoming a large portion of the energy footprint in ICT. Thus the concept of energy efficient or green networking has been introduced. Now one of the main concerns of network industry is to minimize energy consumption of network infrastructure because of the potential economic benefits, ethical responsibility, and its environmental impact. In this paper, the energy management strategies to reduce the energy consumed by network switches in LAN (Local Area Network) have been developed. According to the lifecycle assessment of network switches, during usage phase, the highest amount of energy consumed. The study considers bandwidth, link load and traffic matrixes as input parameters which have the highest contribution in energy footprint of network switches during usage phase and energy consumption as output. Then with the objective of reducing energy usage of network infrastructure, the feasibility of putting Ethernet switches hibernate or sleep mode was investigated. After that, the network topology was reorganized using clustering method based on the spectral approach for putting network switches to hibernate or switched off mode considering the time and communications among them. Experimental results show the interest of this approach in terms of energy consumption

Host and Network Optimizations for Performance Enhancement and Energy Efficiency in Data Center Networks

Modern data centers host hundreds of thousands of servers to achieve economies of scale. Such a huge number of servers create challenges for the data center network (DCN) to provide proportionally large bandwidth. In addition, the deployment of virtual machines (VMs) in data centers raises the requirements for efficient resource allocation and find-grained resource sharing. Further, the large number of servers and switches in the data center consume significant amounts of energy. Even though servers become more energy efficient with various energy saving techniques, DCN still accounts for 20% to 50% of the energy consumed by the entire data center. The objective of this dissertation is to enhance DCN performance as well as its energy efficiency by conducting optimizations on both host and network sides. First, as the DCN demands huge bisection bandwidth to interconnect all the servers, we propose a parallel packet switch (PPS) architecture that directly processes variable length packets without segmentation-and-reassembly (SAR). The proposed PPS achieves large bandwidth by combining switching capacities of multiple fabrics, and it further improves the switch throughput by avoiding padding bits in SAR. Second, since certain resource demands of the VM are bursty and demonstrate stochastic nature, to satisfy both deterministic and stochastic demands in VM placement, we propose the Max-Min Multidimensional Stochastic Bin Packing (M3SBP) algorithm. M3SBP calculates an equivalent deterministic value for the stochastic demands, and maximizes the minimum resource utilization ratio of each server. Third, to provide necessary traffic isolation for VMs that share the same physical network adapter, we propose the Flow-level Bandwidth Provisioning (FBP) algorithm. By reducing the flow scheduling problem to multiple stages of packet queuing problems, FBP guarantees the provisioned bandwidth and delay performance for each flow. Finally, while DCNs are typically provisioned with full bisection bandwidth, DCN traffic demonstrates fluctuating patterns, we propose a joint host-network optimization scheme to enhance the energy efficiency of DCNs during off-peak traffic hours. The proposed scheme utilizes a unified representation method that converts the VM placement problem to a routing problem and employs depth-first and best-fit search to find efficient paths for flows.

How to cope with air transport disruptions: airport airside resilience and vulnerability

The efficiency of airport airside operations is often compromised by unplanned disruptive events of different kinds, such as bad weather, strikes or technical failures, which negatively influence the punctuality and regularity of operations, causing serious delays and unexpected congestion. They may provoke important impacts and economic losses on passengers, airlines and airport operators, and consequences may propagate in the air network throughout different airports. In order to identify strategies to cope with such events and minimize their impacts, it is crucial to understand how disruptive events affect airports’ performance. The research field related with the risk of severe air transport network disruptions and their impact on society is related to the concepts of vulnerability and resilience. The main objective of this project is to provide a framework that allows to evaluate performance losses and consequences due to unexpected disruptions affecting airport airside operations, supporting the development of a methodology for estimating vulnerability and resilience indicators for airport airside operations. The methodology proposed comprises three phases. In the first phase, airside operations are modelled in both the baseline and disrupted scenarios. The model includes all main airside processes and takes into consideration the uncertainties and dynamics of the system. In the second phase, the model is implemented by using a generic simulation software, AnyLogic. Vulnerability is evaluated by taking into consideration the costs related to flight delays, cancellations and diversions; resilience is determined as a function of the loss of capacity during the entire period of disruption. In the third phase, a Bayesian Network is built in which uncertain variables refer to airport characteristics and disruption type. The Bayesian Network expresses the conditional dependence among these variables and allows to predict the impacts of disruptions on an airside system, determining the elements which influence the system resilience the most.

Regional Effects of Port Infrastructure: A Spatial CGE Application to Brazil

This article attempts to elucidate one of the mechanisms that link trade barriers, in the form of port costs, and subsequent growth and regional inequality. Prior attention has focused on inland or link costs, but port costs can be considered as a further barrier to enhancing trade liberalization and growth. In contrast to a highway link, congestion at a port may have severe impacts that are spread over space and time whereas highway link congestion may be resolved within several hours. Since a port is part of the transportation network, any congestion/disruption is likely to ripple throughout the hinterland. In this sense, it is important to model properly the role nodal components play in the context of spatial models and international trade. In this article, a spatial computable general equilibrium (CGE) model that is integrated to a transport network system is presented to simulate the impacts of increases in port efficiency in Brazil. The role of ports of entry and ports of exit are explicitly considered to grasp the holistic picture in an integrated interregional system. Measures of efficiency for different port locations are incorporated in the calibration of the model and used as the benchmark in our simulations. Three scenarios are evaluated: (1) an overall increase in port efficiency in Brazil to achieve international standards; (2) efficiency gains associated with decentralization in port management in Brazil; and (3) regionally differentiated increases in port efficiency to reach the boundary of the national efficiency frontier.

A new diffusion and flow theory for activated carbon from low pressure to capillary condensation range

In this paper, we develop a theory for diffusion and flow of pure sub-critical adsorbates in microporous activated carbon over a wide range of pressure, ranging from very low to high pressure, where capillary condensation is occurring. This theory does not require any fitting parameter. The only information needed for the prediction is the complete pore size distribution of activated carbon. The various interesting behaviors of permeability versus loading are observed such as the maximum permeability at high loading (occurred at about 0.8-0.9 relative pressure). The theory is tested with diffusion and flow of benzene through a commercial activated carbon, and the agreement is found to be very good in the light that there is no fitting parameter in the model. (C) 2001 Elsevier Science B.V. All rights reserved.