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In recent years, some historians started to experiment with computer-generated virtual environments as a new medium for representing spatial history beyond the written language; unfolding new potentials for understanding and representing history. The new medium introduces often neglected sensory modalities and the exposition of some aspects of history that may otherwise go unnoticed. It affords the use of phenomenology and semiotics as theoretical lenses for interpreting the past in ways not possible in traditional media. It also often employs symbolic realism (the use of perspectival constructions that emulate everyday experience) to enable new forms of individual and social engagements with the past. In doing so, it raises new epistemological questions not typically encountered by historians using traditional media. This paper aims to clarify some of the assumptions and premises at work in reconstructing the past using computer-generated virtual environments. It examines some epistemological concerns with the use of phenomenology and semiotics as theoretical lenses. It also explores the potentials and limitations of symbolic realism and its offshoots: the suspension of disbelief and the suspension of imagination.

Spatial behavior is a principal aspect for architects to consider. Unfortunately, it is sometimes hard to predict, as users of space seldom follow a standard routine. However, predicting user behavior in a space can potentially illuminate the entire design process. Moreover, it is a key factor in fighting the recent COVID-19 pandemic. Until most of the public gets their vaccine, health officials recommend social distancing as the primary means of fighting the pandemic. This paper uses an agent-based modeling and simulation (ABMS) approach to reproduce, analyze, and predict spatial behavior during the pandemic in a school environment and its impact on disease propagation. The simulation reproduces the behavior of teachers and students at a sample elementary school. By manipulating parameters that simulate the school officials' response to the pandemic, stakeholders can assess the most effective preventive measures. As a result of running multiple scenarios, the study demonstrates how varying starting conditions and alternate spatial behaviors could lead to different results, providing insight to stakeholders on how to handle disease spread in school environments. [ABSTRACT FROM AUTHOR]

A speed-estimation technique for induction machines, based on carrier signal injection and the standard two-axis smooth-air-gap induction machine model, is presented. The proposed speed-estimation technique can work over a wide range of operating points, including fundamental de excitation. The stability of the algorithm is analyzed using a two-time-scale approach. Based on the estimated rotor speed, a torque controller is designed. Experimental results are presented confirming the validity of this approach. A method to reduce torque ripple generated by the injected carrier signals is also introduced. Index Terms--Carrier signal injection, induction motor drives, speed sensorless, torque control.

This paper presents an analytical method of modeling permanent magnet (PM) motors. The model is dependent only on geometrical and materials data which makes it suitable for insertion into design programs, avoiding long finite element analysis (FEA) calculations. The modeling procedure is based on the calculation of the air gap field density waveform at every time instant. The waveform is the solution of the Laplacian/quasi -Poissonian field equations in polar coordinates in the air gap and takes into account slotting. The model allows the rated performance calculation but also such effects as cogging torque, ripple torque, back-emf form prediction, some of which are neglected in commonly used analytical models. Index Terms--Analytical models, finite element analysis, permanent magnet synchronous motor design.

In this paper, an optimum-efficiency control scheme of synchronous reluctance motors is presented. There exists a variety of combinations of d- and q-axis current which provides a specific motor torque. The objective of the optimum-efficiency controller is to seek a combination of d- and q-axis current components, which provides minimum input power, that is, minimum losses at a certain operating point in steady state. A small amount of perturbation is added to the d-axis current reference for the purpose of searching a minimum input power operating point. Index Terms - Optimum-efficiency operation, synchronous reluctance motor.

In this paper, a new design concept of a PM machine for flux weakening operation is proposed. The feasibility of strong flux weakening capability without permanently demagnetizing the permanent magnet is investigated. Results from the finite element analysis on the proposed PM machine structure are presented to verify the new design concept.

A new multiple coupled circuit model is presented for simulation of induction machines with both arbitrary winding layout and/or unbalanced operating conditions. The model is derived by means of winding functions. No symmetry is assumed. The parameters of the model are calculated directly from the geometry and winding layout of the machine. The behavior of an induction machine during starting is simulated using this model. The results are shown to be in good agreement with the solution obtained by a conventional d - q model for symmetric conditions. The new model is then extended to the solution of a wide variety of fault conditions such as broken bars and end rings and open or short circuited motor coils.

Despite broad adoption of Digital Human Models (DHMs) in other disciplines, the use of ergonomics in interior design heavily depends on design standards that offer rigid guidelines that do not adapt to design or human schemata. Digital ergonomic assessments and DHMs help designers predict and evaluate comfort for more human-centered designs. This paper proposes a framework to incorporate digital ergonomic evaluations to quantify and assess interior spaces' ergonomic comfort using customized DHMs. The framework demonstrates a closed feedback loop connecting 3D models with Human Builder to perform quantitative ergonomic tests while offering real-time results with design recommendations. This implementation showed that individual physical capabilities affected the users' comfort and design outcomes. [ABSTRACT FROM AUTHOR]

Beyond the glamour of Cairo history lies a different side of the city that unravels the unique beauty of urban decay. Al-Hattaba, a UNESCO heritage area, is caught in between these narrations of beauty and decay; the beautiful home whose inhabitants want to keep and grow, and the formally enlisted dangerous informal space subject to eviction and demolition. Al-Hattaba embraces the beauty of its rich and diverse history, growing through time. It beholds moments of prosperity, failure, change, beauty, and loss. Urban decay photography is used to interpret al-Hattaba's controversy and explore the bonds between time and memory. We take the reader through a visual journey in al-Hattaba. It constitutes a photo-sequence that considers al-Hattaba in reflection of its background context, the Citadel of Saladin; historic and residential buildings, some abandoned and attempts of local renovation. This urban setting reflects a rich visual diversity that witnessed its changes through time. We argue that the essence of al-Hattaba's beauty is in its urban decay. It is a space that will never fail to amaze its visitors with its hidden beauty. [ABSTRACT FROM AUTHOR]

A speed-estimation technique for induction machines, based on carrier signal injection and the standard two-axis smooth- air-gap induction machine model, is presented. The proposed speed-estimation technique can work over a wide range of operating points, including fundamental dc excitation. The stability of the algorithm is analyzed using a two-time-scale approach. Based on the estimated rotor speed, a torque controller is designed. Ex- perimental results are presented confirming the validity of this approach. A method to reduce torque ripple generated by the injected carrier signals is also introduced. [ABSTRACT FROM AUTHOR]

This paper presents a position-sensorless vector torque controller designed to achieve maximum efficiency over a range of power and rotational speed for a synchronous reluctance machine. A model of the synchronous reluctance machine is presented which incorporates both winding and core losses. It is then shown that a stator-flux-oriented control scheme can achieve synchronous operation of the machine without a position sensor at medium and high electrical frequencies. For a given speed and torque, power losses in the machine are shown to be a function of only the stator flux magnitude. As the power losses are a convex function of the stator flux level, the optimal flux value can be found using a one-dimensional optimization algorithm, such as the Method of Sequential Quadratic Interpolations. Optimal flux values for a synchronous reluctance machine are determined using an experimental setup that accurately determines losses in the motor/drive system. Experimental results obtained from the test setup confirm the validity of the controller and the optimization algorithm. [ABSTRACT FROM AUTHOR]