This paper presents a novel approach to assessing some of the electric vehicles(EVs) critical environmental conditions without relying on physical sensors. The proposed approach employs distributed estimation in networked vehicles to estimate parameters that characterize the EV's environmental conditions which impact the range of an EV. The parameters to be estimated are the highly uncertain quantities such as wind speed and rolling resistance. Key to this approach is the setmembership filtering (SMF) method, which is quite different from the traditional adaptive filtering methods. The SMF aims to meet a specification on the filtering error magnitude, instead of minimizing the time average or ensemble average of the squared errors. Moreover, the SMF algorithms feature datadependent selective update of parameter estimates, which is very useful in estimating the environmental parameters of networked vehicles. The estimation schemes developed here use a vehicle longitudinal model and commonly available vehicle sensor signals. Simulations are performed to demonstrate the advantages of the proposed algorithms in terms of computational complexity, residual parameter uncertainties, and steadystate mean-squared errors in comparison to existing algorithms.

This paper presents energy-optimal speed trajectories between stops for electric vehicles. It is shown that if basic infrastructure and traffic flow information is available, energy savings of up to 60% are possible, with 20-40% being typical values. The optimization approach uses a cost function that contains only transportation energy and uses all other conditions (such as maximum acceleration, average speed, etc.) as constraints. Real-world considerations such as following distance to the next vehicle and jerk constraints are also analyzed. The overall impact of this approach includes the reduction of energy cost, grid power demand, power plant emissions, global warming, as well as an increase in the range of electric vehicles.

This paper addresses the problem of energy-optimal vehicle-speed trajectories between stops. The ideal parameter-dependent trajectory is introduced, and it is shown that it reduces transportation energy drastically relative to “typical trajectories” seen in traffic. The resulting trajectories can easily be implemented in self-driving cars and have the potential to significantly reduce transportation energy in networked vehicles and cities. The usage of this energy-optimal speed trajectories between stops can save significant amounts of energy, sometimes in excess of 30% when comparing to conventional traffic flow speed profiles. This paper also addresses the impact that vehicle and segment parameters have on the savings. The role of parameters such as the air drag coefficient, cross-sectional area, vehicle mass, efficiency, segment length, average speed, as well as acceleration capability are investigated. It is shown that optimizing speed trajectories to minimize transportation energy consistently results in energy savings. However, diminishing returns are observed for certain scenarios, such as long, low-speed segments.

This paper investigates the benefits of exploiting weather conditions for energy optimal driving. Optimization approaches are introduced that are based on the fact that weather-dependent speed profiles can save transportation energy, especially for electric transportation systems. Optimization models for both minimum transportation energy with travel time constraints and minimum travel time with transportation energy constraints are introduced and the resulting speed profiles are analyzed. Infinite dimensional optimization models are proposed for exact problem descriptions and approximate discretized convex models are derived for highly efficient solutions. The optimization tasks are formulated as a deterministic as well as a robust optimization problem, where weather conditions such as wind speed and rolling resistance effects are assumed to be known exactly or within uncertainty bounds. Simulations illustrate the utility of the proposed optimization models and demonstrate achievable efficiency improvements.

A stochastic energy aware routing framework is proposed for electric vehicles with the goal of enhancing the sustainability of future electrified transportation systems. A stochastic decision making framework is introduced to handle the random effects of environmental factors on transportation energy cost. The problem of optimal routing is formulated as a stochastic programming problem and risk control of the overall energy is applied to find the minimum energy route. The original discrete optimization problem is tackled using convex relaxation and transformation. The optimal path is constructed using a highly efficient primal-dual interior point algorithm for the relaxed problem with a subsequent reconstruction of the solution for the original discrete problem. Two electric drive limitations, i.e., battery capacity and drive line efficiency, are made an integral part of the decision making framework in order to obtain realistic results by incorporating actual vehicle data. Detailed simulations demonstrate the utility of the introduced approach and its superiority to existing, traditional routing engines.

This paper analyzes the inherent limitations of the magnitude response in non-negative impulse response (NNIR) systems that are not of the lowpass type. In particular, this work shows the importance of the frequency response around the point of zero frequency and its effect on the achievable gain increases at higher frequencies. The findings are shown to serve as a guiding principle for the design of NNIR filters that are not of the low pass type.

This paper presents several fundamental frequency-domain bounds for a non-negative impulse response (NNIR) filter. Upper-bounds on power spectral attenuation and power spectral gain in geometrically spaced frequency regions are derived, when power spectral attenuation near frequency zero is limited. By analyzing the tightnesses of these bounds, the relationship between the maximally allowable power attenuation and gain is also treated. All results hold for both continuous and discrete-time domains.

This paper presents fundamental limitations imposed on the frequency response of a filter by a non-negative impulse response (NNIR). Several upper-bounds on power spectral attenuation/gain in linearly spaced frequency regions are derived. These upper-bounds serve as a guide in the design of NNIR filters.

A framework for the combination of evidence in an environment where data are generated from heterogeneous sources possessing partial or incomplete knowledge about the global network scenario is presented. The approach taken is based on the conditional belief and plausibility notions in Dempster-Shafer evidence theory that allow one to condition these partial knowledge bases so that only that portion of the incoming evidence that is relevant is utilized for updating an existing knowledge base. The strategy proposed enables one to accommodate some of the most challenging, yet essential, features that are encountered when evidence is generated from possibly a large numbers of sources. These include heterogeneity and reliability of incoming evidence, inertia and integrity of evidence already gathered, and potentially limited resources at the nodes where evidence updating is carried out. The proposed framework is applied in robot map discovery using ultrasonic sensors and a real-world scenario where sensor data generated by heterogeneous sensors are used for potential threat carrier-type detection

A novel approach named recursive evidence filtering for information processing in distributed sensor networks (DSNs) is presented. It is based on the Dempster-Shafer (DS) formalism, facilitating evidence exchange and fusion in a simple and straightforward manner, while accommodating for partial and incomplete information. Certain restrictions on the coefficients impose several challenges in the design of such evidence filters suggesting that arbitrary frequency shaping is not possible. A general design procedure for IIR type evidence filters is presented with examples

We present a physically realizable UAV model for locating and tracking chemical clouds. Simulation results are presented for implementations of this model with two configurations, one that is faster and requires more space to avoid collisions, and one that is slower and can cover an area more densely. Heterogeneous swarms of agents are shown to have better performance than homogeneous swarms of similar size because they take advantage of the strengths of each configuration.

A distributed task-oriented self-organization algorithm that enables sensors in an ad-hoc network to organize them according to the task being announced is proposed in this paper. When a task is announced, a distributed leader election algorithm is used to select the sensor that best 'matches' the announced task based on minimizing a distance measure between the task and sensor specifications. The selected sensor then uses a task decomposition method to generate and announce the residual tasks that 'cover' the matching error. In this manner, sensors are sequentially selected until all residual tasks are 'covered'. All sensors selected by the algorithms from a sensor group for the originally announced task. To improve the communication overhead of a previous version of this algorithm, location information of each sensor is used to dynamically maintain a contributor group of sensors that may contribute to the announced task. Leader election and all task announcements are confined to this group.

A new, more realistic model for the available bit rate traffic class in ATM network congestion control with explicit rate feedback is introduced and analyzed. This model is based on recent results by M.M. Ekanayake ("Robust stability of discrete time nonlinear systems", Ph.D. dissertation, Univ. Miami, Coral Gables, FL, 1999) regarding discrete time models for time-variant delays. The discrete time model takes into account the effect of time-variant buffer occupancy levels of ATM switches, thus treating the case of time-variant delays between a single congested node and the connected sources. For highly dynamic situations, such a model is crucial for a valid analysis of the resulting feedback system. The new model also handles the effects of the mismatch between the resource management cell rates and the variable bit rate controller sampling rate as well as buffer and rate nonlinearities. A brief stability study shows that an equilibrium in the buffer occupancy is impossible to achieve in the presence of time-variant forward path delays. Stability conditions for the case of time-variant delays in the return path are presented. Finally, illustrative examples are provided.

Some important properties of recursive block floating point systems are derived. On their basis an algorithm for searching limit cycles in such systems is proposed. For any finite wordlength implementation of linear systems, an ellipsoidal set of initial conditions is found which generates all limit cycle in the system. It is applicable for any exhaustive search algorithm and also yields a sufficient condition for absence of limit cycles in (block) floating point systems. Es werden einige wichtige Eigenschaften rekursiver Systeme mit Block-Gleitkomma-Arithmetik hergeleitet. Auf ihrer Basis wird ein Suchalogrithmus für Grenzzyklen in solchen Systemen vorgeschlagen. Für alle möglichen Realisierungen linearer Systeme mit endlicher Wortlänge wird eine ellipsoide Menge von Anfangsbedingungen gefunden, die alle Grenzzyklen des Systems erzeugt. Sie ist für beliebige vollständige Suchalgorithmen anwendbar und erzeugt auch eine hinreichende Bedingung für die Abwesenheit von Grenzzyklen in (Block-)Gleitkomma-Systemen. Nous dérvons quelques propriétés importantes des systèmes en virgule flottante récursifs par bloc. Sur la base de celles-ci un algorithme pour la recherche de cycles limites dans de tels systèmes est proposé. Pour toute implantation en précision finie de systèmes linéaires, un ensemble ellipsoı̈dal de conditions initiales, qui génère tous les cycles limites dans le système, est trouvé. Ceci est applicable à tout algorithme de recherche exhaustive et fournit également une condition suffisante pour l’absence de cycles limites dans les systèmes (par blocs) à virgule flottante.

Different options for block floating point filter implementation are introduced and their efficiency determined. The efficiency is quantified by the additional number of operations over those required for fixed point operation. Some of the implementations are new. It is shown that they are more efficient than the existing ones. Examples are given in which the processing time per recursion of a block floating point implementation on a fixed point processor is approximately the same as the recursion time of the corresponding fixed point implementation. Application of block floating point arithmetic to block implementations is also considered.

In this paper, an algorithm that can be utilized to determine the presence or absence of limit cycles in fixed-point implementation of digital filters is given. It is applicable for filters in state-space formulation (and hence, application to the corresponding direct form follows as a special case), and is independent of the order, type of quantization, and whether the accumulator is single- or double-length. Bounds on the amplitude and period of possible limit cycles are presented. The robustness of the algorithm in terms of limit cycle performance with respect to filter coefficient perturbations is verified. The algorithm is then used to obtain regions in the coefficient space where a filter of given order is limit cycle free. In this process, we have obtained limit cycle free regions that were previously unknown for the two's complement case.

This paper addresses the asymptotic stability of linear shift-variant difference equations whose coefficients are uncertain in an m-dimensional hyperdiamond. The approach used here allows the construction of regions in the coefficient space guaranteeing asymptotic stability that extend beyond the region specified by existing results.

The paper analyzes the asymptotic response behavior of direct form block floating point digital filters. The analysis is valid independent of the order or the quantization scheme used. Absolute bounds on the quantization error are derived and conditions for the existence of certain response types, the corresponding bounds on the output, and criteria for zero convergence are derived. Using sufficiently long block mantissa registers, the limit cycle amplitude can be made arbitrarily small by choosing the block exponent register length large enough.>

The problem of global asymptotic stability in nonlinear recursive digital m-D filters with a first hyper-quadrant causality structure is addressed. Necessary 1-D conditions, which are simple to check, are derived in the form of m 1-D nonlinear system equations. Generalizations to /spl nu/-dimensional (/spl nu/>

This paper analyzes the problem of global asymptotic stability of delta-operator formulated discrete-time systems implemented in fixed-point arithmetic. It is shown that the free response of such a system tends to produce period one limit cycles if conventional quantization arithmetic schemes are used. Explicit necessary conditions for global asymptotic stability are derived, and these demonstrate that, in almost all cases, fixed-point arithmetic does not allow for global asymptotic stability in delta-operator formulated discrete-time systems that use a short sampling time.>

This paper addresses the BIBO (bounded-input bounded-output) stability of a class of discrete 2-D transfer functions in the presence of nonessential singularities of the second kind (NSSK's) on the unit bidisk. Conditions under which the double bilinear transformation (DBT) preserves stability are derived. The results presented here also extend the class of systems whose stability can be predicted. Use of the inverse DBT to produce a continuous equivalent of the discrete 2-D transfer function allows easy application of a continuous-domain equivalent of a criterion developed by Dautov. The necessary and sufficient condition for stability derived in this work provides a simple check for the class of systems under consideration.>

It is shown that floating point realizations of linearly stable systems can exhibit four fundamental types of free responses. The effects of various floating point arithmetic reformatting schemes on the convergence of autoregressive difference equations are addressed. Truncation and rounding quantization schemes as well as double and single length product mantissa schemes are analyzed and compared.>

The problem of determining the existence of limit cycles in direct form digital filters with quantization nonlinearities under zero-input conditions is considered. A method based on an exhaustive search is introduced. It is independent of the number or the type of quantizers and is applicable to filters of any order. The advantage of this algorithm over previous methods is its ability to always determine the stability or instability of a particular realization. The method was implemented for second-order direct form digital filters. Significant improvements over previous results were obtained for the following cases of quantization schemes: one two's complement truncation quantizer and two two's complement truncation quantizers.>