Ambulance Locations in a Tiered Emergency Medical System in a City

This paper deals with optimizing the location of ambulance stations in a two-tiered emergency medical system in an urban environment. Several variants of station distribution are calculated by different mathematical programming models and are evaluated by a detailed computer simulation model. A new modification of the modular capacitated location model is proposed. Two ways of demand modelling are applied; namely, the aggregation of the ambient population and the aggregation of permanent residents at the street level. A case study of the city of Prešov, Slovakia is used to assess the models. The performance of the current and proposed sets of locations is evaluated using real historical data on ambulance trips. Computer simulation demonstrates that the modular capacitated location model, with the ambient population demand, significantly reduces the average response time to high-priority patients (by 79 s in the city and 62 s in the district) and increases the percentage of high-priority calls responded to within 8 min (by almost 4% in the city and 5% in the district). Our findings show that a significant improvement in the availability of the service can be achieved when ambulances are not accumulated at a few stations but rather spread over the city territory.

Virtual and Physical Prototyping of Reconfigurable Parallel Mechanisms with Single Actuation

The paper presents novel models of reconfigurable parallel mechanisms (RPMs) with a single active degree-of-freedom (1-DOF). The mechanisms contain three to six identical kinematic chains, which provide three (for the tripod) to zero (for the hexapod) uncontrollable DOFs. Screw theory is applied to carry out mobility analysis and proves the existence of controllable and uncontrollable DOFs of these mechanisms. Each kinematic chain in the synthesized mechanisms consists of planar and spatial parts. Such a design provides them with reconfiguration capabilities even when the driving link is fixed. This allows reproduction of diverse output trajectories without using additional actuators. In this paper, the model of a mechanism with six kinematic chains (hexapod) has been virtually and physically prototyped. The designing and assembling algorithms are developed using the detailed computer-aided design (CAD) model, which was further used to carry out kinetostatic analysis considering complex geometry of mechanism elements and friction among all contacting surfaces of joints. The developed virtual prototype and its calculation data have been further applied to fabricate mechanism elements and assemble an actuated full-scale physical prototype for future testing.

Coverage versus response time objectives in ambulance location

Background: This paper deals with the location of emergency medical stations in a large-scale area. Operations research tools are used to design a new infrastructure that reflects demographic changes.Methods: A bi-criteria mathematical programming model is proposed. The criteria include the accessibility of high-priority patients in a short time limit and response time of all patients. The model is compared with the p-median model with a single response time objective and with a hierarchical pq-median model that considers different vehicle types. A detailed computer simulation model is used to evaluate the solutions.Results: The methodology is verified in the conditions of the Slovak Republic using real historical data on ambulance trips. Considerable improvements regarding the average response time, coverage of population and coverage of high-risk patients can be achieved by redistributing current stations. In a large-scale area, the coverage objective does not work well. It does not outperform the response time objective that enables saving more lives. The best results are achieved by the hierarchical median-type model.Conclusions: The resulting distribution of ambulances significantly improves the accessibility of urgent health care to patients.

Performance Analysis of Topologies for Autonomous Hybrid Microgrids in Remote Non-Interconnected Communities in the Amazon Region

This work presents a detailed comparative analysis of dispersed versus centralized Alternating Current (AC)-coupling topologies and AC-coupling versus Direct Current (DC)-coupling topologies in autonomous Photovoltaic (PV)-diesel-battery microgrids for remote/isolated communities in the Brazilian Amazon region. The comparison concerned the power losses occurring in power conversion devices and in a low-voltage distribution network by using the balance-of-system (BOS) efficiency as a performance index. The analyses were performed by an analytical approach and by detailed computer simulations in MATLAB/Simulink software. Based on the matching factor (MF), the gain obtained in BOS efficiency is 1.5% for low values of the MF, and for high values of the MF, the centralized topology has the same BOS efficiency as the dispersed topology. In conclusion, this factor proved to be useful as a design parameter for selecting the optimal topology of a PV-diesel-battery microgrid.

Skeletal animation for visualizing dynamic shapes of macromolecules

We apply a skeletal animation technique developed for general computer graphics animation to display the dynamic shape of protein molecules. Polygon-based models for macromolecules such as atomic representations, surface models, and protein ribbon models are deformed by the motion of skeletal bones that provide coarse-grained descriptions of detailed computer graphics models. Using the animation software Blender, we developed methods to generate the skeletal bones for molecules. Our example of the superposition of normal modes demonstrates the thermal fluctuating motion obtained from normal mode analysis. The method is also applied to display the motions of protein molecules using trajectory coordinates of a molecular dynamics simulation. We found that a standard motion capture file was practical and useful for describing the motion of the molecule using available computer graphics tools.

Polarized Rigid Del Pezzo Surfaces in Low Codimension

We provide explicit graded constructions of orbifold del Pezzo surfaces with rigid orbifold points of type ki×1ri(1,ai):3≤ri≤10,ki∈Z≥0 as well-formed and quasismooth varieties embedded in some weighted projective space. In particular, we present a collection of 147 such surfaces such that their image under their anti-canonical embeddings can be described by using one of the following sets of equations: a single equation, two linearly independent equations, five maximal Pfaffians of 5×5 skew symmetric matrix, and nine 2×2 minors of size 3 square matrix. This is a complete classification of such surfaces under certain carefully chosen bounds on the weights of ambient weighted projective spaces and it is largely based on detailed computer-assisted searches by using the computer algebra system MAGMA.

Simulating Bee Pollination for Horticultural Applications

We depend on wild and managed bees for the pollination of a third of fruits, vegetables and nuts for human consumption. Consequently, the details of the interactions between bees and flowers are of utmost concern to growers and seed producers. However, due to the increasing variability of our climate, the loss of bees’ natural habitat, the use of pesticides and the industrialisation of agriculture, the interactions between bees and our flowering crops are changing in complex ways. Traditional field trials are one approach helping to establish how these changes are impacting on food production, but these techniques are time-consuming, season-limited, and susceptible themselves to the same rapid and dynamic disruptions the ecosystems are subject to. Instead, we propose an iterative experimental approach, in which detailed computer simulations that predict how best to run field trials, are repeatedly informed by field observations and field trial outcomes. The simulations account for bee species’ unique perceptual, behavioural, physiological and morphological characteristics, and realistically model the bees’ foraging environments, including open fields, protected crops, and natural ecosystems. We explain how our simulations work, and provide case studies detailing the results of experiments with planting layout to boost pollination. These models lead to improved plant/pollinator interaction management. They have the potential to boost yield, quality, and shelf-life for a variety of crops, to raise food security generally, and to improve the sustainability of our farm and natural ecosystem management practices.

MCQ Examinations for Large Number of Students: Design and Grading

In this paper, a proposal for a criterion for designing and implementing MCQ exams in engineering mechanics course is introduced. The special case of a very large number of engineering students in Alexandria University is considered as a case study. In this case, a quick, though accurate and fair, method of evaluating students’ performance is a must especially when using the credit hour system. Full Multiple-Choice Questions (MCQ) and computer based exams become so common. However, hybrid/subjective or total subjective exams are still in use in some institutions. Even though the process of implementing MCQ exams is well known and mature in humanity courses, in technical courses, sometimes, this process is not straightforward. It may depend on experience as it becomes well established and of minimum time after being applied for many years. In addition, the technical ability of the used software gives instructors more capabilities in analyzing results and establishing a basis for learning statistics. The case of coordinated engineering mechanics course with large number of students is emphasized. A hierarchy of procedures starting from ideas of questions till finishing grading and inputting grades in bulk into online system is formulated. The proposed methodology is of low cost and not so sensitive to technical abilities of software. Also, it doesn’t require instructors with detailed computer knowledge. Finally, it can be used by instructors in other universities as it formulated to be of generic nature.

COMPARING BUILDING SURFACES’ ORIENTATIONS TO OPTIMIZE SOLAR ENERGY COLLECTION

ABSTRACT Net-zero and other high performance green buildings normally do or should include optimized solar energy systems. While detailed computer-based energy simulations of buildings’ energy systems are becoming near-commonplace for many projects, simple, easy-to-use data tables are beneficial earlier in the design process to help guide preliminary decisions in all projects. Practical lookup tables, and then comparison of the data they contain, are also very useful for teaching new concepts, in this case for learning about solar orientations in sunny locations. Engineers, architects, design-build contractors, students, and other designers of green buildings can benefit through knowing, in advance, how exterior surfaces’ orientations increase or decrease the total annual solar energy arriving upon those surfaces. For example, maximizing the incoming energy on a particular roof is advantageous for gathering solar energy for heat or for conversion of that sunlight to electricity, but various requirements often limit designers’ choices for surfaces’ orientations. This paper presents simple tables that form a tool for making initial decisions on surfaces’ directions and slopes; the user can then study various effects further, such as local factors including cloudiness and shading, with detailed software. The classical solar geometry equations utilized are documented here for repeatability of the research, but are not necessary for use of this paper’s tables. Practical examples are given too to help readers use the tables.