In this paper, a compact tuneable dual-band slot antenna operating over the frequency range from 560 MHz to 1 GHz is presented and evaluated through a hardware-in-the-loop test-bed. The co-existence of high order modulation schemes is investigated in Digital Terrestrial Television (DTT) and low Long-Term Evolution (LTE) bands. Error Vector Magnitude (EVM) results show that the proposed antenna can support two operating frequency bands simultaneously where each band can be tuned independently for carrier aggregation with negligible crosstalk.
There exist several classes of physical interventions to address congestion at arterials, including widening (construction of additional lanes) and upgrading to expressway standards where possible. For each class of intervention, a key question is the threshold or benchmark traffic volume (BTV) at which the intervention is feasible. For long-term congestion mitigation planning for multiple arterial sections in a network and for planning-phase corridor development, agencies desire to identify BTVs for congestion mitigation interventions. The existing literature addresses this issue largely in feasibility analysis for specific projects, with little or no guidance regarding network-level planning considerations. In addressing this gap, this paper presents a detailed network-level planning methodology that is rooted in economic efficiency. The methodology first establishes three basic alternatives—Do-Nothing, Widening, and Upgrade-to-Expressway—and expresses the total lifecycle cost for each alternative as a function of the current traffic volume in terms of average daily traffic (ADT). The BTV is identified as the ADT at which the lifecycle costs of any two alternatives are equal. This paper demonstrates the application of the proposed methodology using data from in-service roads, and the results indicate that the relative weights assigned to the agency and user costs significantly influence the BTVs. In addition, results are presented for the scenario where these two cost categories are assigned equal weights; for this scenario, widening is never the best option. In the probabilistic situation, it is found that, at an 80% confidence level, it is economically attractive to upgrade a four-lane major arterial to an expressway when the ADT reaches 6,000; at the 100% confidence level, it is economically attractive to upgrade to an expressway when the ADT reaches 19,000.
Transportation agencies strive to maintain their systems in good condition and also to provide acceptable levels of service to users. However, funding is often inadequate to meet the needs of system preservation and expansion, and thus performance- and budget-constrained optimization continues to be an issue. Adding complexity to this issue is the increasing visibility of different stakeholders who advocate for consideration of a multiplicity of diverse perspectives in the highway decision-making process. Thus agencies are grappling with the issue of how best to incorporate multiple performance objectives in their decision-making processes. Some of these objectives conflict with each other, and therefore a need arises for decisionmakers to find optimal solutions that examine the tradeoffs and provide a reasonable balance between the different objectives. Furthermore, there is the issue of uncertainty: outcomes of projects are never exactly what the decision-makers envisage; if such inevitable uncertainties are not duly accounted for, the final decision that may seem optimal may actually be associated with high risk. Finally, at most agencies, the management of highway assets is divided into several sub-areas such as pavements and safety assets. In this management structure, optimal management decisions are carried out separately for specific types of highway assets or management systems but do not always guarantee a global optimal strategy for all the management systems combined. Thus, a decision-making framework that integrates all asset types is needed to enhance decision-making and to ensure more efficient use of scarce funds. Clearly, a need exists for a multi-objective decision-making problem that integrates the various management systems, duly incorporates uncertainty, and helps decision-makers assess the tradeoffs between the performance measures. This study addresses that need. This report presents innovative techniques for carrying out multiple-criteria project selection and tradeoff analysis among the different management systems that comprise highway asset management. A key product of this study is the development of a novel project selection framework formulated as a multi-objective optimization problem.
A method of modelling creeping waves on PEC cylinders when illuminated by a perpendicular plane wave is discussed. The limitations of this technique will be considered, and an alternative method will be suggested for use with higher frequencies, and for the purposes of computing propagation constants.
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