Hyper-Spherical Search (HSS) algorithm: a novel meta-heuristic algorithm to optimize nonlinear functions

This paper proposes a novel optimization algorithm called Hyper-Spherical Search (HSS) algorithm. Like other evolutionary algorithms, the proposed algorithm starts with an initial population. Population individuals are of two types: particles and hyper-sphere centers that all together form particle sets. Searching the hyper-sphere inner space made by the hyper-sphere center and its particle is the basis of the proposed evolutionary algorithm. The HSS algorithm hopefully converges to a state at which there exists only one hyper-sphere center, and its particles are at the same position and have the same cost function value as the hyper-sphere center. Applying the proposed algorithm to some benchmark cost functions shows its ability in dealing with different types of optimization problems. The proposed method is compared with the genetic algorithm (GA), particle swarm optimization (PSO) and harmony search algorithm (HSA). The results show that the HSS algorithm has faster convergence and results in better solutions than GA, PSO and HSA.     

A novel symmetric/asymmetric multilevel current source inverter topology with lower number of components and lowest power rating of switches

A novel multilevel current source inverter (MCSI) configuration is introduced in this paper. The ability of handling with asymmetrical DC sources is one of the substantial advantages of the proposed inverter. In asymmetric mode, by appropriate selection of DC sources magnitude, a considerable increase can be obtained in the number of output levels without any manipulation on inverters’ hardware. In MCSIs, the number of required circuit devices is very important because the overall costs, circuit size, reliability and control complexity are dependent on them directly. The proposed inverter can generate all desired current levels using a lower number of elements. Besides, it is known that reduction of number of switches from conventional inverters imposes an undesired increase in total semiconductor device power (SDP). But, the total SDP of the proposed inverter is kept equal to conventional inverter. To validate the superiority of the proposed inverter, a full comparison is provided. Also, the computer simulation and experimental results are presented.     

The Artless Word: Mies van der Rohe on the Building Art

Abstract

The project was the first-place winner of a design-build competition initiated by the Student Forum at The Harvard Design School. Faculty and students served on the jury for the competition. Students were challenged to design a new mail-slot system for 320 students with removable name labels. The competition offered students an opportunity to realize a project and, through that process, explore and learn about design, material properties, fabrication, and construction techniques. The resulting proposal is a new piece of informational infrastructure that engages the physical and digital transfer of information.     

Surface: A-Tectonic of Roofing and Wrapping

This paper makes the claim that a different understanding of architecture prevails when criticism aims at exploring the threshold between theory and architectural autonomy. To navigate in the realm of theory, and to lend form merely to the vicissitudes of cultural theories, dismisses both history andarchitecture's position in the capitalist cycle of production and consumption. This paperer attempts to historicize contemporary architecture in reference to Gottfried Semper s theory of dressing. The intention is to demonstrate that proliferation of the tectonic rapport between the two elements of roof and clothing is informed by the conflation of architecture's interiority with digital techniques. Semper is important today because his idea of theatricality provides a useful tool for analysing the expressionistic tendencies of computer-generated forms, and the latter's relation to the aesthetics of commodity fetishism. Once a semi-autonomous understanding of architecture is established, an argument can be made to plot two recent projects by Peter Eisenman and Renzo Piano in the context of what might be called topological tectonics. The binary underpinning of this comparison is prohlematized when Greg Lynn's views on the tectonics of blob are included in the fuzzy picture of current architectural theories.     

Kenneth Frampton,David Malouf and Juhani Pallasma,Glenn Murcutt,Architect

This article uses Christmas Island as a site to discuss the contested history of Australian immigration in terms of the built environment. Offshore detention centres and the political systems for detaining asylum seekers pose substantial demands of institutional design, control of populations, and psychic anxieties associated with the arrival of foreigners. Systems of detention are explored through the topics of territory, human labour, boats as visual signs, and the buildings constructed to house detainees. Entangled orders of security expose detention as a timely subject for architectural intervention and commentary.     

Reconfiguration and DG Sizing and Placement Using Improved Shuffled Frog Leaping Algorithm

Abstract

In this paper is proposed a reconfiguration methodology with the presence of Distributed Generation (DG), aimed at achieving the minimum power loss, minimum number of switching operation and minimum deviation of bus voltage while satisfying all constraints using improved shuffled frog leaping algorithm (ISFLA).The performance of the proposed method is examined on 33 and 69 bus IEEE test distribution systems. The ISFLA performance is evaluated with the well-known algorithm including of harmony search algorithm (HSA), refined genetic algorithm (GRA), particle swarm optimization (PSO), differential evolutionary (DE) and conventional SFLA. Simulation results showed that the total power loss and voltage bus minimum in primary distribution network can be reduced significantly. Also the results in different scenarios are showed that the simultaneous reconfiguration and DG placement method is better in less losses and also in more minimum voltage. Moreover, the ISFLA superiority is proved in comparison with the HAS, GRA, PSO, DE, and SFLA in view of more convergence speed and accuracy and also converges in less number iteration. Also, the performance of the proposed method is favorable compared to previous studies.     

Hybrid modelling of inhomogeneous transformer winding for very fasttransient overvoltage studies

This paper presents a novel approach for the modelling of transformer windings, which is valid in the frequency range of 10 kHz to a few MHz. It is a hybrid model; coil-by-coil detailed plus inter-coil black box model. The parameter estimation of the detailed model and the synthesis of the black box model is based on frequency domain measurements. The technique is applied to a high-voltage transformer winding. The comparison of the measurements and the frequency domain simulation of the model with EMTP confirms the validity and accuracy of the model for the intended frequency range. Experiments in the frequency range of several MHz reveal that remarkable overvoltages appear at the connecting point of the inverted and interleaved part of this winding. It is shown that the reason of the VFTO (very fast transient overvoltage) in the MHz range is the inhomogeneity of the winding parts     

Hot Expansion of a Thin-Walled Cylindrical Shell of Porous Material

A system of equations describing the hot expansion of a thin-walled cylindrical shell of porous material by internal pressure was obtained. The solution was based on one of the simplest creep theories, namely, work hardening theory. The radial, meridial, and volume rates of creep deformation were calculated in comparison with the basic circumferential deformation rate of the shell. The numerical results were obtained by considering a process of stepwise loading of the shell. It was established that porosity in the material decreases the limiting value of internal pressure of the shell.     

Sensitivity Analysis on Ladder Network Equivalent Circuit Parameters of Power Transformer

In this article, novel methods and ideas are introduced, which altogether lead to an accurate model of power transformer windings. First, by the determination of non-dominant (hidden) resonances from frequency-response tests, a ladder model is proposed. Next, it is improved by assigning different values for similar elements of each section of the model. The parameters are obtained by minimizing the error function via a genetic algorithm. Sensitivity analysis is then applied to the obtained model to achieve further examinations and tests. Measurements have been driven from the windings of a 20/0.4-kV, 1600-kVA transformer. Modeling, methodologies, and sensitivity analysis in this article can be very useful for future research aiming to find internal faults of the transformer with the frequency response analysis.     

A zero-current switching switched-capacitor DC-DC converter with reduction in cost,complexity, and size

This paper presents a new step-up switched-capacitor (SC) DC-DC converter which has many advantages such as reduction in investment cost, control complexity, number of components, voltage stress on components, and size over traditional topologies. In the proposed structure, power switches are reduced in number which in turn leads to the merits mentioned earlier and makes the converter more suitable for industrial applications. Furthermore, a previously introduced zero-current switching (ZCS) method is used here which provides soft switching for the devices. There is also a reduction in the number of required inductors to achieve ZCS due to the decreased number of switches in the proposed converter. The proposed converter is validated by comprehensive simulation results in MATLAB Simulink environment and also precise experimental results which show the acceptable performance of the proposed topology.