Modeling the power consumption of a Wifibot and studying the role of communication cost in operation time

Mobile robots are becoming part of our every day living at home, work or entertainment. Due to their limited power capabilities, the development of new energy consumption models can lead to energy conservation and energy efficient designs. In this paper, we carry out a number of experiments and we focus on the motors power consumption of a specific robot called Wifibot. Based on the experimentation results, we build models for different speed and acceleration levels. We compare the motors power consumption to other robot running modes. We, also, create a simple robot network scenario and we investigate whether forwarding data through a closer node could lead to longer operation times. We assess the effect energy capacity, traveling distance and data rate on the operation time

Diefenbaker, Latin America and Caribbean: The Pursuit of Canadian Autonomy

John Diefenbaker’s Latin American policy was based on his vision of Canada’s national interest, which placed a strong emphasis on the achievement of greater autonomy in foreign policy for Canada vis-à-vis the US and the expansion of Canadian exports to the region. For Diefenbaker, an enhanced relationship with Latin America had the potential to lessen Canada’s dependency on the US, while giving Latin American countries an outlet for their trade, commercial and financial relations other than the US. This new approach implied that Canada would formulate and implement policy that focused more on Canadian political interests and goals. It was not a matter of charting a totally independent policy for Canada in Latin America –– true policy independence was impossible to achieve. Nor was it the case that Canada would necessarily set itself in opposition to the US when it disagreed with its policies. For Diefenbaker the goal was to pursue a foreign policy that was aligned with, but not subservient to, the US. Ultimately, Diefenbaker’s policies towards countries such as Cuba, Mexico, the Federation of the West Indies, Argentina and Brazil were somewhat successful in expanding Canadian trade and commercial activity beyond the United States, and in establishing a stronger political relationship between Canada and the Latin American region. The policies were remarkably consistent, reflecting Diefenbaker’s desire to increase Canada’s autonomy, and differentiated by his personal involvement in initiating policy at the Cabinet level and in building and cultivating relationships with Latin American leaders; the goal was to further Canadian economic and political interests in the region. Though there were possibilities for greater expansion and connections with Latin America that were missed, Diefenbaker’s Latin American policy would be built upon and continued by successive Liberal and Conservative governments once he left office

The γδ T Lymphocytes of the Perinatal Murine Thymus

We have previously shown that the adult thymus contains three subsets of γδ T cells that can be defined by the expression of Thy-1 and heat-stable antigen (HSA). In this study, the number of cells in each of these thymic γδ populations was investigated at different stages throughout life. In adult mice, the populations stayed relatively constant, however, in contrast, there were major variations in them early in development. It was shown that only two of the γδ populations were present in the prenatal thymus, a major population of Thy-1+ HSA- cells, and a smaller population of Thy-1+ HSA- cells. However, after birth, most of the Thy-1+ HSA-cells appear to loose the Thy-1 antigen, forming the third population of HSA- Thy-1-cells. The adult configuration of populations appeared to be established within the first week after birth. Therefore, whereas the γδ populations stayed relatively constant from this time point onwards, there were major variations early in development. Throughout life, most γδ thymocytes are CD4- CD8-, however, in the neonatal thymus, there are some CD4+ and CD8+ γδ thymocytes, and these are contained in the Thy-1+ HSA- population

Resolving mass tort cases under the Companies' Creditors Arrangement Act in Canada : learning from the United States experience

This thesis describes, compares and assesses the ways in which mass tort claims are addressed through United States and Canadian insolvency legislative structures. The thesis begins by examining how courts in the United States use the Bankruptcy Code to reorganize companies facing extreme financial strain because of mass tort claims. The areas examined include: the consolidation of claims; the automatic stay; the requirement of insolvency; the various tort claims that are involved in the mass tort case; the plan; and the confirmation of the plan. The thesis then examines how Canadian courts can, and have, used the CCAA to reorganize or restructure companies dealing with mass tort claims. The Canadian Red Cross reorganization is used to demonstrate the complexity involved in resolving mass tort cases under Canadian insolvency legislation, specifically focusing on the steps that a company must follow to receive protection and how the plan can deal with tort claims. The issue of insolvency is examined as Canadian courts require a company to be insolvent in order to receive CCAA protection. This thesis argues that a broader definition of insolvency should be adopted. The thesis also addresses the following: how a stay of proceedings is obtained; the appointment of a monitor to oversee the reorganization; the classes; the plan; the sanction (court approval) of the plan; and the types of tort claims that are involved in mass tort insolvency reorganizations. What makes mass tort insolvency cases so unique and difficult are the tort claimants and how they fit into the reorganization process. The types of claimants that arise are examined in detail and include: claimants with judgments; claimants who have filed actions but have not obtained judgments; claimants whose injuries have manifest themselves but have not yet filed actions; contingent claimants, identified “claimants” who have been exposed to the defective or dangerous product but have not manifested injuries; and future claimants who have been exposed to the defective or dangerous product but who have not been identified at the relevant time. The courts in both countries have included all claims that have manifested injuries before an application for reorganization and both countries have found ways to include contingent and future claims (unmanifested injuries) by using trusts. Mass tort case law in both Canada and the United States is examined to show how trusts are established by the courts to allow tort claims, including future unidentified claims, to be included in the plan. The outcome of these cases is examined and assessed. United States case law is used to show how Canada can make mass tort insolvency cases more successful in the future by avoiding the administrative costs of frivolous claims and setting up “best offer/no negotiation schemes” as well as codifying a number of aspects that arise in mass tort cases such as the definition of mass torts, future claims representatives and channeling injunctions to also decrease time and money on arguing to allow these into the CCAA. The purpose of the CCAA is to provide a company with a fresh start while also providing the creditors of the company with the best possible return; mass tort insolvency cases achieve this goal

Sustainability Assessment: Offsetting Carbon Emissions from Energy Use at the Orthodox Academy of Crete (OAC)

Mitigation of climate change and development of ecological practices is an important goal in religious organizations. Current work aims in the investigation of the possibility of offsetting the net carbon emissions due to energy use in the Orthodox Academy of Crete (OAC), Greece. Energy generated by fossil fuels and renewable energy sources is currently used in the premises of the Academy. The total annual energy consumption and the energy sources currently used in the religious organization are initially estimated. Various future scenarios are investigated regarding energy consumption in the Academy, energy sources used and their carbon emissions, as well as the possibility of carbon emissions sequestration with various tree plantations. The annual energy consumption in the Academy has been estimated at 264,257 KWh while its energy consumption per covered area is 31.31 KWh/m2. Among various energy sources used, electricity has the highest share at 95.76%, while 32.47% of the overall energy consumption is currently generated by a solar-PV system installed on-site. It is indicated that the combined use of energy-saving techniques and technologies, the higher use of various renewable energy sources and the sequestration of any remaining carbon emissions with tree plantations could eliminate all carbon emissions due to energy use in the Academy.  The most appropriate sustainable energy technologies are solar-thermal, solar-PV and high efficiency heat pumps which are currently mature, reliable and cost-effective. Additionally olive tree orchards, carob tree orchards and Eucalyptus tree plantations could be created for carbon emissions sequestration. It has been concluded that with the reduction of the current energy consumption by 20%, the installation of a solar-PV system at 50 KWp, and the creation of an olive tree orchard at 14 ha, the net annual carbon emissions due to energy use in the Academy could be eliminated. The results indicate the way that the Orthodox Academy of Crete could zero its impacts on climate change due to energy use in its premises

Routage multi-flots économe en énergie dans les réseaux de capteurs et actionneurs

International audienceL'introduction d'actionneurs capables de se déplacer sur ordre dans les réseaux de capteurs a permis l'émergence d'un nouveau genre de protocoles de routage. Ceux-ci tirent parti de cette nouvelle possibilité de relocaliser les éléments du réseau pour adapter dynamiquement sa topologie au trafic. Ils vont ainsi faire se déplacer physiquement les nœuds au fur et à mesure du routage afin d'optimiser le coût des transmissions radio. Toutefois, dans les réseaux de capteurs, il y a souvent plusieurs nœuds géographiquement proches pour reporter un même événement à la station de base. Les messages routés empruntent alors différents chemins qui sont physiquement proches, et certains nœuds appartiennent à plusieurs d'entre eux. Ces derniers vont alors sans cesse devoir se relocaliser sur les différents chemins et donc mourir prématurément. En réponse à ce problème, nous proposons PAMAL, le premier protocole de routage qui optimise la topologie réseau et sait tirer avantage des intersections des chemins de routage de manière complètement locale. PAMAL va ainsi provoquer la fusion des chemins de routage qui se croisent, et ce de plus en plus près des sources au cours et du temps. Les résultats de simulations montrent que ce comportement associé à un mécanisme d'agrégation permet d'améliorer la durée de vie du réseau de 37 %

A Comprehensive Survey on RF Energy Harvesting: Applications and Performance Determinants

\ua9 2022 by the authors. Licensee MDPI, Basel, Switzerland.There has been an explosion in research focused on Internet of Things (IoT) devices in recent years, with a broad range of use cases in different domains ranging from industrial automation to business analytics. Being battery-powered, these small devices are expected to last for extended periods (i.e., in some instances up to tens of years) to ensure network longevity and data streams with the required temporal and spatial granularity. It becomes even more critical when IoT devices are installed within a harsh environment where battery replacement/charging is both costly and labour intensive. Recent developments in the energy harvesting paradigm have significantly contributed towards mitigating this critical energy issue by incorporating the renewable energy potentially available within any environment in which a sensor network is deployed. Radio Frequency (RF) energy harvesting is one of the promising approaches being investigated in the research community to address this challenge, conducted by harvesting energy from the incident radio waves from both ambient and dedicated radio sources. A limited number of studies are available covering the state of the art related to specific research topics in this space, but there is a gap in the consolidation of domain knowledge associated with the factors influencing the performance of RF power harvesting systems. Moreover, a number of topics and research challenges affecting the performance of RF harvesting systems are still unreported, which deserve special attention. To this end, this article starts by providing an overview of the different application domains of RF power harvesting outlining their performance requirements and summarizing the RF power harvesting techniques with their associated power densities. It then comprehensively surveys the available literature on the horizons that affect the performance of RF energy harvesting, taking into account the evaluation metrics, power propagation models, rectenna architectures, and MAC protocols for RF energy harvesting. Finally, it summarizes the available literature associated with RF powered networks and highlights the limitations, challenges, and future research directions by synthesizing the research efforts in the field of RF energy harvesting to progress research in this area

Design Considerations for Time-Slotted LoRa(WAN)

One of the most common issues in wireless networks is the problem of increasing the network capacity by alleviating or eliminating collisions with the minimum possible cost. The combination of time division protocols together with efficient slot allocation mechanisms is an effective way to achieve scalability and provide high reliability. In this paper, I describe the parameters that must be taken into account when designing LoRa(WAN)-based time-slotted protocols. I show that the LoRaWAN case differs from any other synchronous wireless solution mainly due to the characteristics of the LoRa physical layer and the regional radio duty cycle restrictions. I also propose a frame structure which has been adopted during the implementation of a time-slotted LoRa approach

Energy Efficient Mobile Target Tracking Using Flying Drones

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