A 2D model for the study of equilibrium glide paths of UiS Subsea Freight-Glider

A planar mathematical model for the analysis of equilibrium glide paths of the UiS subsea freight-glider (USFG) is presented. The model is developed using Simscape Multibody in MATLAB/Simulink to study the ever-changing dynamics of the glider. Motion along the heave and pitch direction is regulated by two separate PID controllers. Controllers are tuned for the optimal bandwidth and phase margin to provide the system with ideal gains which satisfy the system requirements. A wide-ranging sensitivity investigation is carried out on the USFG by changing the two key variables, pump flow rate and ballast fraction. The results reflect the advantages of using higher flow capacity and ballast fraction, which should be preferred according to the application, provided if there are no space and weight restrictions. Finally, different glide paths were simulated to observe that, controller gains obtained from the linear model can be improved to acquire better performance in terms of robustness and stability of the system.

Weight restrictions for the DEA model in the presence of dual-role factors: An application to the Iranian banking sector

A production process transforming multiple inputs to different outputs is considered in conventional data envelopment analysis (DEA) models. In various settings, however, there are factors that simultaneously play the roles of both input and output called dual-role factors. In some situations, additional information is available to impose on a DEA model with dual-role factors, or the decision maker is forced to impose some restrictions regarding the importance of dual-role factors on the model. Toward this end, the current research employs two different weighting methods to introduce various weighted DEA models in the presence of dual-role factors. To strengthen the accuracy of the new models, their properties are discussed. Then, each new model is illustrated in details by a numerical example. Moreover, to show that the new models are applicable, they are applied to the Iranian banking sector. To do this, $ 20 $ bank branches which have dual-role factors are assessed. At last, to show the outcome of weight restrictions, the results obtained by each new model are compared with those from Cook and Zhu's model (2007).

Neurological Considerations for the Care of Patients With Severe Obesity

Patients with severe obesity tend to have higher rates of morbidities which can complicate and even lengthen their hospital admission course. Hospitals which do not have the resources to efficiently manage bariatric patients due to equipment weight-restrictions should be proactive in their care and knowledgeable about their options to avoid long delays in treatment. Amid this obesity epidemic, the neurologist plays a role in the inpatient management of patients with severe obesity and could serve as a channel to improve the quality of care and reduce the length of stay. We present a case of a patient with severe obesity who presented with visual loss secondary to idiopathic intracranial hypertension. The patient’s treatment was delayed several weeks from the time of admission until his weight decreased enough to safely undergo CT imaging in the operating room, developing complications throughout the course of his stay. This paper highlights the identified barriers of care and potential solutions to ensure improvement in the quality of care of patients with severe obesity, in order to reduce preventable complications.

A Fuzzy Network DEA Approach to the Selection of Advanced Manufacturing Technology

The selection of advanced manufacturing technologies (AMTs) is an essential yet complex decision that requires careful consideration of various performance criteria. In real-world applications, there are cases that observations are difficult to measure precisely, observations are represented as linguistic terms, or the data need to be estimated. Since the growth of engineering sciences has been the key reason for the increased utilization of AMTs, this paper develops a fuzzy network data envelopment analysis (DEA) to the selection of AMT alternatives considering multiple decision-makers (DMs) and weight restrictions when the input and output data are represented as fuzzy numbers. By viewing the multiple DMs as a network one, the data provided by each DM can then be taken into account in evaluating the overall performances of AMT alternatives. In the solution process, we obtain the overall and DMs efficiency scores of each AMT alternative at the same time, and a relationship in which the former is a weighted average of the latter is also derived. Since the final evaluation results of AMTs are fuzzy numbers, a ranking procedure is employed to determine the most preferred one. An example is used to illustrate the applicability of the proposed methodology.

Evolution of extreme hot temperatures over Euro-Mediterranean main airports

<p><span><span>As a result of global warming, the magnitude and the frequency of extreme hot temperature events have increased remarkably in the recent decades. </span><span>In the absence of policies, global warming is expected to continue during the next years, and certain regions which are already characterized by warm and hot temperatures, such as the Euro-Mediterranean region, may be notably impacted in numerous and diverse fields. The aeronautical sector is among these vulnerable fields, as aircraft takeoff performances also depend on air temperature. For instance, a</span><span>n increase in ground temperature results in a decrease in air density, and consequently in the available thrust for takeoff. This may lead to flight delays, weight restrictions or even flight cancellations. Concerning the aircraft engines, an increase in temperature may negatively impact the performance and may also lead to an increase of pollutant emissions into the atmosphere. All of these effects would have a social, economic and health impact.</span></span></p><p><span><span>In this study we analyze the evolution of extreme hot temperatures on aircraft performance over the main airports in the Southern Euro-Mediterranean region, using simulations performed by regional climate models (RCMs) from the Euro-CORDEX international exercise. To this end, we first evaluate RCMs in terms of their representation of extreme hot temperatures and their trends in the present period by comparing to different observational datasets and also to the driving GCMs. The results of this comparison show that RCMs don't </span><span>represent better the amplitude nor the temporal trends of hot temperature events in summer</span><span>, despide their higher spatial resolution. We assess the changes in the hot temperature extremes from the Euro-CORDEX future projections and we evaluate the risk of weight restriction in the next decades.</span></span></p>

Using Spreadsheet Maps for the Placement of Low Altitude Platform (LAP) Wireless Network Nodes After Disasters

Low altitude platform (LAP) architectures are an emerging platform for providing temporary wireless network connectivity to areas with a damaged fixed wireless network infrastructure. The authors propose a spreadsheet-based approach for practitioners to locate LAP nodes in the field. This approach does not require radio frequency propagation expertise and incorporates standard models to display the coverage areas for the placement of LAP aerial devices. The proposed tool allows the transmission range for a given aerial device to be visually optimized during deployment. The spreadsheet-based tool the authors are proposing is expressly suited for battery-powered LAP architecture devices with payload weight restrictions, such as those utilizing balloons or kites, that can be quickly deployed by emergency responders. An additional contribution of this work is the development of a hybrid propagation model for LAP device transmissions for deployments above 200 meters which is absent in the literature. This model is a linear combination of two existing models for free space radio propagation.

Alpine ungulate movement: Quantification of spatiotemporal environmental energetics and social interaction

Species movement, an animal’s ability to change its location, is a fundamental property of life, and animals have diverse physical and behavioural attributes that are believed to enhance efficient travel and optimization of resources. Quantifying movement energetics and returns to examine these ideas over relevant time- and space scales is, however, problematic. In this thesis, I set out to develop and use advanced biologging tag technology to determine a second by second account of the behaviour and location of tagged animals to unveil where and when key behaviours are occurring, to answer key questions about feeding and social behaviour, allocation in space and the energetic costs associated with different movement decisions. Specifically, I used accelerometers, magnetometers, temperature and pressure sensors with GPS units in animal-attached loggers to examine key questions linking movement, energetics and feeding and aggressive behaviours in 3 wild- and 3 domestic ungulate species in mountainous landscapes in the French Alps, monitored for periods between 30 and 200 days. To obtain high-frequency data using electronic devices for long periods, I had to first design new housings to attach safely the loggers to the animals and develop methods for weather proofing the loggers. I designed, using CAD-designa and 3D printing, different housing types and used ‘Guronic’ resin to shockproof and waterproof circuit boards. This allowed me to obtain logging data for up to 200 days. To give a location per second but stay within ethical weight restrictions, the dead-reckoning method to reconstruct fine-scale movements between low resolution GPS fixes was adopted. To improve the accuracy of dead-reckoning estimates I improved the method using behavioural definition to identify real moves (steps, grazing, moving) and distinguish it from resting, grooming and other behaviours not leading to a displacement of the animal in space, allowing to selectively filter data to be dead-reckon. Using the data collected, I showed that central-place-based, but free-roaming, domestic goats exhibited efficient space-use by having time-dependent fanning out from their central place, which reduced local resource depletion. Models predicted that area-use increased logarithmically with herd size and duration. These finding could lead to improved livestock management in multi-functional alpine landscapes, to reduce the risk of over-grazing and manage interactions with other grazing species and clonflicts with other landuse needs. The goat grazing patterns were compared to those of wild ibex and revealed goats to be more adaptable, with the ibex being particularly vulnerable to changes in temperature, exacerbated by them preferring steep slopes with associated high metabolic costs and heat generation during ascent. These results could further inform management decisions regarding the survival of alpine ibex under projected climate change. Furthermore I developed new biologging approaches to investigate social interactions, specifically head-clashing in both species. This agonistic behaviour was associated with competition and the rut in ibex and was quantified using methods first developed for the domestic goat, where the behaviour appeared to relate primarily to competition for food. Using the goat as a surrogate species, the behaviour could be identified and mapped for the ibex, which highlighted areas and times important for head-clashing, including drastic increases during the rut. Finally, movement data and proxies for energy expenditure from three domestic species (sheep, cows and goats) and three wild species (ibex, mouflon and chamois) was utilised to produce species-specific energy landscapes across the terrains they used. This indicated that different anatomies and behaviours resulted in different, species-specific, movement costs for specific topographies and habitats. Energy use for travel across heterogeneous space depends, therefore, on the species concerned. These findings thus highlight the importance to consider that species with different life histories and ecological needs use landscapes in contrasting ways and my results can provide a more refined evidence base for the management and conservation of these species in alpine grasslands. These biologging approaches allow now also to address further management issues such as the responses to disturbances from tourists (hiking, skiers, etc.) and even reveal how species are more susceptible to climate change.

Solar Power Generation System for the Canadian Space Agency STRATOS Program

This paper discusses the design and application of solar photovoltaics (PV) under aerospace conditions. The application of solar PV that is addressed is the Power Distribution Unit (PDU) for the Canadian Space Agency’s (CSA) stratospheric balloon (STRATOS) program. The PDU utilizes four 1 kWh Battery Unit (BUs) that have been sized with volume and weight restrictions in mind. Without the capacity to provide enough energy to support multi-day missions, they are thus supplemented by the solar power generation subsystem presented in this paper. The power generation sub-system includes a bespoke solar panel design and a centralized Maximum Power Point Tracking (MPPT) power conversion unit to maximize the power output of solar panels. The centralized unit can accommodate up to eight solar panels, each consisting of nine individual C60 SunPower solar cells. The centralized MPPT unit consists of two MPPT controllers, each controller supporting up to four solar panels. The MPPT unit is modular and can be easily integrated to the CSA’s existing intelligent Battery Management System (BMS).

Incorporation of Preferences into Supply Chains DEA Efficiency: A Geometric Attribution Approach

Among many applications, several studies using Data Envelopment Analysis (DEA) have examined and studied the efficiency of supply chains. However, the majority of existing approaches dealing with this research area have ignored the important factor of decision makers’ preferences. The main objective of this article is to provide consistent DEA models that allow for efficiency analysis in order to determine the optimal allocation of resources according to these preferences. We propose three cases that are inspired from the geometric decomposition of preference attributions: (1) horizontal attribution, which is when decision makers treat each supply chain as a single non-detachable entity; (2) vertical attribution, which is when decision makers consider supply chains detachable and (3) combined attribution, which is when decision makers concurrently assign weights to the supply chain and to its members. Based on this suggested decomposition, new DEA models are developed, and an illustrative example is applied. The obtained results are relevant and show that DEA is capable of easily incorporating the preferences of decision-makers without resorting to weight restrictions on inputs or outputs.