Indirect Field Oriented Control of Induction Motors is Robustly Globally Stable

Field orientation, in one of its many forms, is an established control method for high dynamic performance AC drives. In particular, for induction motors, indirect fieldoriented control is a simple and highly reliable scheme which has become the de facto industry standard. In spite of its widespread popularity no rigorous stability proof for this controller was available in the literature. In a recent paper (Ortega et al, 1995) [Ortega, R., D. Taoutaou, R. Rabinovici and J. P. Vilain (1995). On field oriented and passivity-based control of induction motors: downward compatibility. In Proc. IFAC NOLCOS Conf., Tahoe City, CA.] we have shown that, in speed regulation tasks with constant load torque and current-fed machines, indirect field-oriented control is globally asymptotically stable provided the motor rotor resistance is exactly known. It is well known that this parameter is subject to significant changes during the machine operation, hence the question of the robustness of this stability result remained to be established. In this paper we provide some answers to this question. First, we use basic input-output theory to derive sufficient conditions on the motor and controller parameters for global boundedness of all solutions. Then, we give necessary and sufficient conditions for the uniqueness of the equilibrium point of the (nonlinear) closed loop, which interestingly enough allows for a 200% error in the rotor resistance estimate. Finally, we give conditions on the motor and controller parameters, and the speed and rotor flux norm reference values that insure (global or local) asymptotic stability or instability of the equilibrium. This analysis is based on a nonlinear change of coordinates and classical Lyapunov stability theory

The Political Economy of Local Infrastructure Planning

Developing countries face considerable challenges in the design and operation of local infrastructure planning systems in decentralized or decentralizing countries. Many of these are well documented, but the complex political economy environment in which planning evolves has received insufficient attention. The forces driving decentralization and other public sector reforms shape how planning emerges, functions and performs. Local planning involves a range of differentially empowered and variously motivated actors at multiple levels and in diverse ways. The dynamics among them can support or undermine authentic local planning, with potentially significant implications for results. This paper reviews the evolution of local infrastructure planning with a focus on least developed countries, outlining the key expected and observed relationships among decentralization, planning systems and infrastructure development. The main goal is to create greater awareness of political economy issues that could inform the design and management of more effective and pragmatic local infrastructure planning systems

03/25/1948 Letter from the Exchange Club of Lewiston

Letter from Paul J. Fortier, President, and Romeo Poirier, Board of Control, of the Exchange Club of Lewiston to Louis-Philippe Gagné.https://digitalcommons.usm.maine.edu/fac-lpg-letters-1948-01-06/1022/thumbnail.jp

Estimation De Canal Et Performances Du Précodeur Hybride Pour La Transmission En Ondes Millimétriques

Les systèmes de communication mobile de nouvelles générations devraient permettre des performances accrues non pas seulement en termes de débit et de latence, mais aussi en termes d’efficacité spectrale. La transmission en ondes millimétriques est un des points essentiels de son déploiement. Comme ces ondes sont facilement atténuées dans notre environnement, son déploiement n’est possible qu’avec l’utilisation d’antennes directionnelles ou du moins une technique alternative tel que le beamforming. Le beamforming numérique ne peut cependant pas être appliqué pour les ondes millimétriques à cause de la consommation en énergie excessive et les contraintes de hardware. Le beamforming analogique introduit des erreurs importantes qui réduisent les performances du système. Le précodage hybride sera de ce fait la meilleure alternative pour permettre la mise en place du beamforming en ondes millimétriques et offrir les mêmes performances qu’un beamforming numérique. L’algorithme choisi pour la conception des matrices de précodage se base sur l’OMP qui est un algorithme glouton de résolution de problème parcimonieuse utilisé dans la branche de l’acquisition compressée

Nomenclature and syntaxonomic notes on some high-rank syntaxa of the European grassland vegetation

We present descriptions of a new order (Ranunculo cortusifolii-Geranietalia reuteri) and of a new alliance (Stachyo lusitanicae-Cheirolophion sempervirentis) for the herbaceous fringe communities of Macaronesia and of the southwestern Iberian Peninsula, respectively. A new alliance, the Polygalo mediterraneae-Bromion erecti (mesophilous post-cultural grasslands), was introduced for the Peninsular Italy. We further validate and typify the Armerietalia rumelicae (perennial grasslands supported by nutrient-poor soils on siliceous bedrocks at elevations characterized by the submediterranean climate of south-central Balkan Peninsula), the Securigero-Dasypyrion villosae (lawn and fallow-land tall-grass annual vegetation of Italy), and the Cirsio vallis-demoni-Nardion (acidophilus grasslands on siliceous substrates of the Southern Italy). Nomenclatural issues (validity, legitimacy, synonymy, formal corrections) have been discussed and clarified for the following names: Brachypodio-Brometalia, Bromo pannonici-Festucion csikhegyensis, Corynephoro-Plantaginion radicatae, Heleochloion, Hieracio-Plantaginion radicatae, Nardetea strictae, Nardetalia strictae, Nardo-Callunetea, Nardo-Galion saxatilis, Oligo-Bromion, Paspalo-Heleochloetalia, Plantagini-Corynephorion and Scorzoneret alia villosae

Towards unlocking the full potential of Multileaf Collimators

International audienceA central problem in the delivery of intensity-modulated radiation therapy (IMRT) using a multileaf collimator (MLC) relies on fi nding a series of leaves confi gurations that can be shaped with the MLC to properly deliver a given treatment. In this paper, we analyse, from an algorithmic point of view, the power of using dual-layer MLCs and Rotating Collimators for this purpose

Proposals (33–34) to conserve the name Poo-Astragalion and to conserve the name Poo-Astragaletum sesamei with a conserved type, and requests (5–7) for a binding decision on the name-giving taxa in the same names and the inversion of the name Poo-Astragaletum sesamei

The alliance name Poo-Astragalion has been widely used by Iberian phytosociologists for nearly fifty years to indicate a type of sheep pastures thriving on base-rich substrates. This alliance is currently classified in the order Poetalia bulbosae and class Poetea bulbosae. However, the revision of its original diagnosis highlights that this alliance name must be considered as an alternative name to the largely disused name Medicagini-Brachypodion distachyi. In order to stabilize the nomenclature, we propose the conservation of the traditionally used name Poo-Astragalion. On the other hand, the type association of the alliance (Poo-Astragaletum sesamei) turns out to be a superfluous name for another association neglected in the syntaxonomical literature, the Astragalo scorpioidis-Medicaginetum truncatulae. Hence, with the same objective of stabilizing the nomenclature, we propose the designation of a conserved neotype for the Poo-Astragaletum sesamei and the conservation of this name against the earlier heterotypic synonym in case of union of both associations. At the same time, we propose to complete the two names Poo-Astragalion and Poo-Astragaletum sesamei by selecting Poa bulbosa and Astragalus sesameus as the name-giving taxa, and to invert the name Poo-Astragaletum in accordance with its neotype (Astragalo sesamei-Poetum bulbosae). (33) Poo-Astragalion Rivas Goday et Ladero 1970: 165–169, nom. cons. propos. Typus: Poo-Astragaletum sesamei Rivas-Goday et Ladero 1970: 166–170 (holotypus). (≡) Medicagini-Brachypodion distachyi Rivas-Goday et Rivas-Martínez in Rivas Goday et Ladero 1970: 165–166 (alternative name) [original form: "Medicago-Brachypodion"] (34) Poo-Astragaletum sesamei Rivas-Goday et Ladero 1970: 166–170, nom. cons. et typus cons. propos. [original forms: "Poo-Astragaletum", "Poeto-Astragaletum sesamei"] Typus cons. propos.: neotypus hoc loco (see below). (=) Astragalo scorpioidis-Medicaginetum truncatulae Rivas Goday et Borja 1959 nom. corr. [original form: Astragalo scorpioidis-Medicaginetum tribuloidis nom. inept. (Rivas Goday and Borja 1959: 475, table 2)] Taxonomic reference: Euro+Med (2023). Syntaxonomic reference: Mucina et al. (2016). Abbreviations: EVC = EuroVegChecklist (Mucina et al. 2016); ICPN = 4th edition of the International Code of Phytosociological Nomenclature (Theurillat et al. 2021)

Optimal Omnitig Listing for Safe and Complete Contig Assembly

Genome assembly is the problem of reconstructing a genome sequence from a set of reads from a sequencing experiment. Typical formulations of the assembly problem admit in practice many genomic reconstructions, and actual genome assemblers usually output contigs, namely substrings that are promised to occur in the genome. To bridge the theory and practice, Tomescu and Medvedev [RECOMB 2016] reformulated contig assembly as finding all substrings common to all genomic reconstructions. They also gave a characterization of those walks (omnitigs) that are common to all closed edge-covering walks of a (directed) graph, a typical notion of genomic reconstruction. An algorithm for listing all maximal omnitigs was also proposed, by launching an exhaustive visit from every edge. In this paper, we prove new insights about the structure of omnitigs and solve several open questions about them. We combine these to achieve an O(nm)-time algorithm for outputting all the maximal omnitigs of a graph (with n nodes and m edges). This is also optimal, as we show families of graphs whose total omnitig length is Omega(nm). We implement this algorithm and show that it is 9-12 times faster in practice than the one of Tomescu and Medvedev [RECOMB 2016]

Arguments for the physical nature of the triggered ion-acoustic waves observed on the Parker Solar Probe

Triggered ion-acoustic waves are a pair of coupled waves observed in the previously unexplored plasma regime near the Sun. They may be capable of producing important effects on the solar wind. Because this wave mode has not been observed or studied previously and it is not fully understood, the issue of whether it has a natural origin or is an instrumental artifact can be raised. This paper discusses this issue by examining 13 features of the data such as whether the triggered ion-acoustic waves are electrostatic, whether they are both narrow-band, whether they satisfy the requirement that the electric field is parallel to the k-vector, whether the phase difference between the electric field and the density fluctuations is 90 degrees, whether the two waves have the same phase velocity as they must if they are coupled, whether the phase velocity is that of an ion-acoustic wave, whether they are associated with other parameters such as electron heating, whether the electric field instrument otherwise performed as expected, etc. The conclusion reached from these analyses is that triggered ion-acoustic waves are highly likely to have a natural origin although the possibility that they are artifacts unrelated to processes occurring in the natural plasma cannot be eliminated. This inability to absolutely rule out artifacts as the source of a measured result is a characteristic of all measurements.Comment: 21 pages, 9 figures, 1 table. arXiv admin note: substantial text overlap with arXiv:2211.1441

Enhanced glutamate, IP3 and cAMP activity in the cerebral cortex of Unilateral 6-hydroxydopamine induced Parkinson's rats: Effect of 5-HT, GABA and bone marrow cell supplementation

Parkinson's disease is characterized by progressive cell death in the substantia nigra pars compacta, which leads to dopamine depletion in the striatum and indirectly to cortical dysfunction. Increased glutamatergic transmission in the basal ganglia is implicated in the pathophysiology of Parkinson's disease and glutamate receptor mediated excitotoxicity has been suggested to be one of the possible causes of the neuronal degeneration. In the present study, the effects of serotonin, gamma-aminobutyric acid and bone marrow cells infused intranigrally to substantia nigra individually and in combination on unilateral 6-hydroxydopamine induced Parkinson's rat model was analyzed. Scatchard analysis of total glutamate and NMDA receptor binding parameters showed a significant increase in Bmax (P < 0.001) in the cerebral cortex of 6-hydroxydopamine infused rat compared to control. Real Time PCR amplification of NMDA2B, mGluR5, bax, and ubiquitin carboxy-terminal hydrolase were up regulated in cerebral cortex of 6-hydroxydopamine infused rats compared to control. Gene expression studies of GLAST, ά-Synuclien and Cyclic AMP response element-binding protein showed a significant (P < 0.001) down regulation in 6-OHDA infused rats compared to control. Behavioural studies were carried out to confirm the biochemical and molecular studies. Serotonin and GABA along with bone marrow cells in combination showed reversal of glutamate receptors and behaviour abnormality shown in the Parkinson's rat model. The therapeutic significance in Parkinson's disease is of prominence