Distributed Receding Horizon Control with Application to Multi-Vehicle Formation Stabilization

We consider the control of interacting subsystems whose dynamics and constraints are uncoupled, but whose state vectors are coupled non-separably in a single centralized cost function of a finite horizon optimal control problem. For a given centralized cost structure, we generate distributed optimal control problems for each subsystem and establish that the distributed receding horizon implementation is asymptotically stabilizing. The communication requirements between subsystems with coupling in the cost function are that each subsystem obtain the previous optimal control trajectory of those subsystems at each receding horizon update. The key requirements for stability are that each distributed optimal control not deviate too far from the previous optimal control, and that the receding horizon updates happen sufficiently fast. The theory is applied in simulation for stabilization of a formation of vehicles

A theoretical analysis of the current-voltage characteristics of solar cells

Various mechanisms which limit the conversion efficiency of silicon solar cells were studied. The effects of changes in solar cell geometry such as layer thickness on performance were examined. The effects of various antireflecting layers were also examined. It was found that any single film antireflecting layer results in a significant surface loss of photons. The use of surface texturing techniques or low loss antireflecting layers can enhance by several percentage points the conversion efficiency of silicon cells. The basic differences between n(+)-p-p(+) and p(+)-n-n(+) cells are treated. A significant part of the study was devoted to the importance of surface region lifetime and heavy doping effects on efficiency. Heavy doping bandgap reduction effects are enhanced by low surface layer lifetimes, and conversely, the reduction in solar cell efficiency due to low surface layer lifetime is further enhanced by heavy doping effects. A series of computer studies is reported which seeks to determine the best cell structure and doping levels for maximum efficiency

A theoretical analysis of the current-voltage characteristics of solar cells

The current-voltage characteristics and efficiencies of solar cells are discussed. For one solar cell structure detailed curves are presented which include carrier densities, current densities, potential, and quasi-Fermi levels at different voltage levels both with and without optically generated carriers (AMO conditions). In addition some results are presented concerning the influence of various parameter variations such as lifetime, cell thickness, and high-low junction width on solar cell performance

A preliminary assessment of age at death determination using the nuclear weapons testing 14C activity of dentine and enamel

Calibration (using CALIBomb) of radiocarbon measurements made on the enamel of human teeth from people born during the nuclear era typically produce 2 possible age ranges that potentially reflect the period of tooth formation. These ranges correspond to periods before and after the 1963 atmospheric 14C maximum. Further measurements made on the collagen component of the combined dentine and cementum from the roots of the same teeth enable the appropriate age range to be selected. Using this range and the formation times for individual teeth, we estimated the year of birth of the individuals and compared these to the known dates of birth. The results were relatively accurate and confirmed those of a previous study by another research group. The present study demonstrates that it is possible to produce a good estimate of the year of birth from a single tooth

Gossip on Weighted Networks

We investigate how suitable a weighted network is for gossip spreading. The proposed model is based on the gossip spreading model introduced by Lind et.al. on unweighted networks. Weight represents "friendship." Potential spreader prefers not to spread if the victim of gossip is a "close friend". Gossip spreading is related to the triangles and cascades of triangles. It gives more insight about the structure of a network. We analyze gossip spreading on real weighted networks of human interactions. 6 co-occurrence and 7 social pattern networks are investigated. Gossip propagation is found to be a good parameter to distinguish co-occurrence and social pattern networks. As a comparison some miscellaneous networks and computer generated networks based on ER, BA, WS models are also investigated. They are found to be quite different than the human interaction networks.Comment: 8 pages, 4 figures, 1 tabl

The Sea Waters surrounding the Québec-Labrador peninsula

L'histoire de l'exploration des eaux côtières de la péninsule Québec-Labrador remonte très loin dans le temps, mais c'est vraiment l'Année polaire internationale de 1882 qui marqua les débuts des premières recherches sérieuses. Les progrès les plus considérables des recherches océanographiques ont cependant été réalisés depuis la IIe guerre mondiale, grâce surtout aux travaux entrepris dans l'Arctique oriental par le Bureau des recherches sur les pêcheries.L'auteur s'étend d'abord sur l'océanographie physique de la région ; il étudie successivement la bathymétrie, la répartition et les caractères des principales masses d'eau, les courants, les glaces et les marées. Suit une analyse de la biologie marine, qui souligne en particulier l'importance d'un facteur : l'absence de brassage vertical des eaux. La répartition de la faune marine indique que si les régions dominées par les eaux arctiques sont riches en mammifères, celles où l'influence atlantique est forte sont de beaucoup les plus poissonneuses. L'auteur insiste sur l'importance des ressources biologiques de la mer dans l'économie alimentaire des Esquimaux.De même qu'il existe des preuves d'oscillations climatiques à courte période, on peut aussi conclure à un réchauffement des eaux depuis le début du siècle, bien que cette tendance soit moins évidente depuis quelques années

Alien Registration- Dunbar, Nellie M. (Jefferson, Lincoln County)

https://digitalmaine.com/alien_docs/12932/thumbnail.jp

Alien Registration- Dunbar, Nina M. (Portland, Cumberland County)

https://digitalmaine.com/alien_docs/24179/thumbnail.jp

The life cycle of Sagitta elegans in Arctic and Subarctic Seas, and the modifying effects of hydrographic differences in the environment

Sagitta elegans arctica of the Canadian eastern Arctic waters has a life span of two years. Its breeding cycle is two-phase, or alternating, and the population consists of two distinct groups breeding in different years. The spawning period is long, extending from July into the winter, probably up to February. Winter spawning is taken to imply that the breeding behaviour is not timed to coincide with the maximum abundance of food, but that the cycle is determined by the growth limitations imposed by the low temperature...