On a class of embeddings of massive Yang-Mills theory

A power-counting renormalizable model into which massive Yang-Mills theory is embedded is analyzed. The model is invariant under a nilpotent BRST differential s. The physical observables of the embedding theory, defined by the cohomology classes of s in the Faddeev-Popov neutral sector, are given by local gauge-invariant quantities constructed only from the field strength and its covariant derivatives.Comment: LATEX, 34 pages. One reference added. Version published in the journa

Delay Tolerant Networking over the Metropolitan Public Transportation

We discuss MDTN: a delay tolerant application platform built on top of the Public Transportation System (PTS) and able to provide service access while exploiting opportunistic connectivity. Our solution adopts a carrier-based approach where buses act as data collectors for user requests requiring Internet access. Simulations based on real maps and PTS routes with state-of-the-art routing protocols demonstrate that MDTN represents a viable solution for elastic nonreal-time service delivery. Nevertheless, performance indexes of the considered routing policies show that there is no golden rule for optimal performance and a tailored routing strategy is required for each specific case

The SU(2) X U(1) Electroweak Model based on the Nonlinearly Realized Gauge Group

The electroweak model is formulated on the nonlinearly realized gauge group SU(2) X U(1). This implies that in perturbation theory no Higgs field is present. The paper provides the effective action at the tree level, the Slavnov Taylor identity (necessary for the proof of unitarity), the local functional equation (used for the control of the amplitudes involving the Goldstone bosons) and the subtraction procedure (nonstandard, since the theory is not power-counting renormalizable). Particular attention is devoted to the number of independent parameters relevant for the vector mesons; in fact there is the possibility of introducing two mass parameters. With this choice the relation between the ratio of the intermediate vector meson masses and the Weinberg angle depends on an extra free parameter. We briefly outline a method for dealing with \gamma_5 in dimensional regularization. The model is formulated in the Landau gauge for sake of simplicity and conciseness: the QED Ward identity has a simple and intriguing form.Comment: 19 pages, final version published by Int. J. Mod. Phys. A, some typos corrected in eqs.(1) and (41). The errors have a pure editing origin. Therefore they do not affect the content of the pape

Comments on the Equivalence between Chern-Simons Theory and Topological Massive Yang-Mills Theory in 3D

The classical formal equivalence upon a redefinition of the gauge connection between Chern-Simons theory and topological massive Yang-Mills theory in three-dimensional Euclidean space-time is analyzed at the quantum level within the BRST formulation of the Equivalence Theorem. The parameter controlling the change in the gauge connection is the inverse $\lambda$ of the topological mass. The BRST differential associated with the gauge connection redefinition is derived and the corresponding Slavnov-Taylor (ST) identities are proven to be anomaly-free. The Green functions of local operators constructed only from the ($\lambda$-dependent) transformed gauge connection, as well as those of BRST invariant operators, are shown to be independent of the parameter $\lambda$, as a consequence of the validity of the ST identities. The relevance of the antighost-ghost fields, needed to take into account at the quantum level the Jacobian of the change in the gauge connection, is analyzed. Their role in the identification of the physical states of the model within conventional perturbative gauge theory is discussed.Comment: 19 pages, LATEX, to appear in Journal of High Energy Physic

Co-simulated digital twin on the network edge: A vehicle platoon

This paper presents an approach to create high-fidelity models suited for digital twin application of distributed multi-agent cyber–physical systems (CPSs) exploiting the combination of simulation units through co-simulation. This approach allows for managing the complexity of cyber–physical systems by decomposing them into multiple intertwined components tailored to specific domains. The native modular design simplifies the building, testing, prototyping, and extending CPSs compared to monolithic simulator approaches. A system of platoon of vehicles is used as a case study to show the advantages achieved with the proposed approach. Multiple components model the physical dynamics, the communication network and protocol, as well as different control software and external environmental situations. The model of the platooning system is used to compare the performance of Vehicle-to-Vehicle communication against a centralized multi-access edge computing paradigm. Moreover, exploiting the detailed model of vehicle dynamics, different road surface conditions are considered to evaluate the performance of the platooning system. Finally, taking advantage of the co-simulation approach, a solution to drive a platoon in critical road conditions has been proposed. The paper shows how co-simulation and design space exploration can be used for parameter calibration and the design of countermeasures to unsafe situations

FROM WIDE- TO SHORT-RANGE COMMUNICATIONS: USING HUMAN INTERACTIONS TO DESIGN NEW MOBILE SYSTEMS AND SERVICES

The widespread diffusion of mobile devices has radically changed the way people interact with each other and with object of their daily life. In particular, modern mobile devices are equipped with multiple radio interfaces allowing users to interact at different spatial granularities according to the various radio technology they use. The research community is progressively moving to heterogeneous network solutions which include many different wireless technologies seamlessly integrated to address a wide variety of use cases and requirements. In 5th- Generation (5G) of mobile network we can find multiple network typology such as device-to-device (D2D), vehicular networks, machine-to-machine(M2M), and more, which are integrated in the existing mobile-broadband technology such as LTE and its future evolutions. In this complex and rich scenario, many issues and challenges are still open from a technological, architectural, and mobile services and applications points of view. In this work we provide network solutions, mobile services, and applications consistent with the 5G mobile network vision by using users interactions as a common starting point. We focus on three different spatial granularities, long, medium/short, and micro mediated by cellular network, Wi-Fi, and NFC radio technologies, respectively. We deal with various kinds of issues and challenges according to the distinct spatial granularity we consider. We start with an user centric approach based on the analysis of the characteristics and the peculiarities of each kind of interaction. Following this path, we provide contributions to support the design of new network architectures, and the development of novel mobile services and applications

Location relevance and diversity in symbolic trajectories with application to telco data

We present an approach to the discovery and characterization of relevant locations and related mobility patterns in symbolic trajectories built on call detail records - CDRs - of mobile phones (telco trajectories). While the discovery of relevant locations has been widely investigated for continuous spatial trajectories (e.g., stay points detection methods), it is not clear how to deal with the problem when the movement is defined over a discrete space and the locations are symbolic, noisy and irregularly sampled, such as in telco trajectories. In this paper, we propose a methodological approach structured in two steps, called trajectory summarization and summary trajectories analysis, respectively, the former for removing noise and irrelevant locations; the latter to synthesize key mobility features in a few novel indicators. We evaluate the methodology over a dataset of approx 17,000 trajectories with 55 million points and spanning a period of 67 days. We find that trajectory summarization does not compromise data utility, while significantly reducing data size. Moreover, the mobility indicators provide novel insights into human mobility behavior

A Study on the Seismic Response of Ground and Reinforced Concrete Buildings in Belgaum Region, India

In the recent years, each unpredictable earthquake (for example Kobe, 1995; Taiwan, 1999; Kocaeli, 1999 and Bhuj, 2001) has revealed its own saga of destruction and failure of engineered structures. Therefore, regional variation in potential earthquake damage should be carefully assessed for better planning towards disaster mitigation. This requires assessment of the seismic ground motion parameters. The present study focus on the seismic response of ground and reinforced concrete buildings in Belgaum region (located in zone III, as per IS 1893–Part1: 2002) in Karnataka state. At present no strong motion records are available in this region and therefore, wavelet-based spectrum compatibility approach is used to generate synthetic earthquake motions for the region. The effect of soil deposits in the region on propagation of seismic motion parameters to the ground surface is investigated based on equivalent linear approach. The Frequency response analysis of buildings of various configurations is carried out with three dimensional numerical modeling. The results indicate the maximum spectral accelerations at the ground surface in the range of 0.68g to 1.29g and peak ground acceleration (PGA) amplifications in the range of 2.16 to 3.13. The predicted fundamental period of soil deposits in the region varies from 0.2 s to 0.4 s. The configuration of buildings susceptible to resonance due to the close matching of resulting wave frequencies of the ground is identified

Algebraic Properties of BRST Coupled Doublets

We characterize the dependence on doublets of the cohomology of an arbitrary nilpotent differential s (including BRST differentials and classical linearized Slavnov-Taylor (ST) operators) in terms of the cohomology of the doublets-independent component of s. All cohomologies are computed in the space of local integrated formal power series. We drop the usual assumption that the counting operator for the doublets commutes with s (decoupled doublets) and discuss the general case where the counting operator does not commute with s (coupled doublets). The results are purely algebraic and do not rely on power-counting arguments.Comment: Some explanations enlarged, references adde