On the Potential of Flow-Based Routing in Multihomed Environments

The data rates provisioned by broadband Internet access connections continue to fall short of the requirements posed by emerging applications. Yet the potential of statistical multiplexing of the last mile broadband connections remains unexploited even as the average utilization of these connections remains low. Despite recent work in this area [15, 20], two key questions remain unanswered: a) What is the attainable benefit of broadband access sharing? and b) How much of this benefit is realizable given real-world constraints? In this work we quantify the attainable benefit of a multihomed broadband access environment by proposing and evaluating several flow-based access sharing policies using a custom flow-based simulator. We then analyze how much of the performance benefit is lost due to real-world constraints by migrating from simulations to a test-lab environment employing a wireless network. Our results show that in today’s broadband Internet access scenarios, a significant reduction in download times by up to a factor of 3 is achievable

Energy and operating cost analysis of the smart-scaled flow route directly to adipic acid

Abstract only

Hydrostratigraphic members of the Edwards Aquifer in Travis and Hays Counties, Texas

UT Librarie

Spatiotemporal modelling of flood-related impacts on daily population movement

This paper presents research combining spatiotemporal population flow data, flood modelling and network analysis to examine the effect of time of flood onset and flood magnitude on travel across a city for commuters and primary school children. Findings quantify that flood onset time has an effect on the disruption to travel comparable to flood event magnitud

Groundwater monitoring network design using GIS and multicriteria analysis

The objective of this investigation was to use multicriteria analysis to analyze and model the main criteria that influence the optimal design of a network to monitor groundwater levels. The multicriteria analysis was performed using a GIS (IDRISI Selva). The Toluca Valley aquifer (Mexico) was chosen as the case study. The definition and importance of the criteria (factors and constraints) that influence the design of the monitoring network were based on available information and consultations with experts in the topic. The factors considered were: rate of decline in groundwater levels, decline in groundwater levels, rise in groundwater levels, cracks, vertical hydraulic gradient, and density of wells. The Analytical Hierarchy Process (AHP) was used to weight the factors, resulting in a consistency ratio of 0.08. The weighted linear combination (WLC) method was then applied which resulted in a map identifying the locations of the priority areas to be monitored. The results show that 1.0 % of the study region corresponds to very high priority monitoring areas, 1.8 % to high priority areas, another 1.8 % to medium priority, 4.4 % to low priority and 91 % to very low priority monitoring areas. The proposed method can be used by government and public and private organizations to determine monitoring strategies that support water resources management

Histomorphometric and Immunohistochemical Study of Early Adaptative Response of the Vascular Wall in a Termino-Terminal Microsurgical Model of Femoral Vessels in Wistar Rat

SUMMARY: When a vein segment is grafted into arterial circulation, biomechanical forces stimulate modification of its structure. This morphological adaptive response is progressive during a medium or long term and occludes the vessel lumen, leading to a graft failure. The objective of this study was to characterize the early morphological response of the vascular wall in a terminal-terminal vascular vein graft model in Wistar rats. A segment of the femoral vein was placed in the femoral circulation. An end to end microsurgical graft anastomosis technique was implemented and standardized in twenty rats. The samples were processed with histological technique to analyze the overall structure with hematoxylin and eosin, the composition of the vessel wall with Masson trichrome technique, the proliferating and smooth muscle cells were detected with immunohistochemistry (anti-PCNA, anti-actin and anti CD68) and the induction of apoptosis with TUNEL technique. The times periods studied were 1, 3 and 5 days postoperative. There is progressive increase of cell proliferation and intensity of the density detected by PCNA with its peak at postoperative day 3. Apoptosis was not evident in any of the postoperative days. Smooth muscle had no significant change in any of the time periods studied. Macrophage and leukocyte migration was evident since the first postoperative day with infiltration into the media by the 5th day. This study characterizes the morphological aspects in the early arterialization of the vascular wall in a vein graft process. These results contribute to a better understanding of the morphopathological mechanism involved in vein graft failure. KEY WORDS: Hyperplasia; Morphology; Microsurgical model; Vascular adaptive changes; Venous graft

Non—cryptographic methods for improving real time transmission security and integrity

In this paper we present a few non cryptographic methods for improving the security, integrity and reliability of real time services. The methods presented in this paper apply to real time transmitting systems, which are based on the Peer-to-Peer (P2P) model. A basic idea of the first technique is to use agents for detecting steganographic content in packet headers, so packets with suspicious entries in the IP header fields will be blocked or the fields will be erased. The two other presented techniques are based on reputation and trust systems, so trust and reputation basic definitions, types and modelling methods are shown. Also a simple design scheme of using these mechanisms in a P2P real-time data transmitting infrastructure is presented. Additionally, we describe an idea of path selecting technique, which can be used to avoid paths that are susceptible to eavesdropping

A new scroll-type air motor with magnetic spirals

The scroll-type air motor, also named the scroll expander, has been widely used for different applications due to its characteristics of compact structure and high energy conversion efficiency. However, the leakage and the friction result in non-negligible energy losses. This paper presents the recent work on developing a new scroll-type air motor with mounted permanent magnetic spirals and investigates its potential in leakage reduction and efficiency improvement, especially at low-pressure air supply conditions. A method for the implementation of the magnetic scroll air motor is proposed. A prototype is manufactured, and initial experimental tests are conducted to study the generalized torque distribution. A mathematical model for the magnetic scroll air motor is developed, and a corresponding simulation study is presented. The study shows that the proposed magnetic scroll air motor structure is feasible in terms of manufacturing and has the potential to reduce the air leakage and, thus, to improve the energy efficiency by a maximum of around 15% at a supply pressure of 2 × 10 5 Pa, with a flank leakage clearance reference of 0.06 mm

Series Hybrid Electric Vehicle Simultaneous Energy Management and Driving Speed Optimization

The energy management (EM) and driving speed co-optimization of a series hybrid electric vehicle (S-HEV) for minimizing fuel consumption is addressed in this article on the basis of a suitably modeled series powertrain architecture. The paper proposes a novel strategy that finds the optimal driving speed simultaneously with the energy source power split for the drive mission specified in terms of the road geometry and travel time. Such a combined optimization task is formulated as an optimal control problem that is solved by an indirect optimal control method, based on Pontryagin’s minimum principle. The optimization scheme is tested under a rural drive mission by extensive comparisons with conventional methods that deal with either speed optimization only or EM strategies with given driving cycles. The comparative results show the superior performance of the proposed method and provide further insight into efficient driving