Common Design Approach Research Articles

Comparing the Rules in Digital Algorithmic Generation Methods for Architectural Designs

The paper deals with digital generative algorithmic systems. Its aim is to investigate the extent to which the difference between rule-based algorithmic systems affects the definition of rules themselves. To achieve this aim, the paper put forward a theoretical framework of rule-based systems including the characteristics of rules, and the way they work. The framework was adopted as a basis for the comparison of four common rule-based algorithmic design approaches in architecture. They are Shape Grammars, L-systems, Cellular Automata, and Swarm Intelligence Algorithm. The results showed that the differences between the rule-based algorithmic systems are slightly reflected in their rules. The similarities are identified in many rule’s properties and their way of work such as: using symbols in the representation of rules, using substitution rules in the generation process, using the same procedures included in rules, the possibility of rule’s repetition and rule’s termination. However, shape grammars showed some individuality, especially in the reference of rules to architectural precedents.

Control of long-term deflections of RC beams using reinforcements and low-shrinkage concrete

An experimentally based programme was conducted to assess the influence of heterogeneity on the long-term deflection of reinforced concrete (RC) elements with compression reinforcement and low-shrinkage concrete. These two structural measures are usually employed by designers to mitigate deflection of concrete beams, slabs and bridge decks due to creep and shrinkage effects. Control of creep and shrinkage deflections is important for successful design of concrete elements as the deflections influence their sizing and thus the associated costs. A 5 year experimental study was undertaken to address the most common alternative design approaches to alleviate long-term deflections of concrete. These included variable reinforcement ratios within the compressive zone, variable tensile reinforcement ratios, low-shrinkage concrete within the compressive zone and a combination of these measures. In total, 12 cantilever beam specimens were tested in the laboratory under controlled environmental conditions, supported by a time-dependent finite-element model. Both numerical and experimental results showed RC beam deflection reductions of up to 85% could be achieved when both compressive reinforcement and low-shrinkage concrete were employed.

Higher-order exceptional points: A route for flat-top optical filters

We study theoretically the formation and properties of higher-order exceptional points (EPs) in optical parity-time symmetric systems (PTSSs) consisting of a finite number of coupled resonators. The analysis shows that only specific configurations of such PTSSs exhibit high-order EPs. We derive the conditions for the formation of higher-order EP in these PTSSs and discuss the properties of the eigenmodes. By taking advantage of the fundamental link between EPs and the formation of a white-light cavity, we utilize the conditions at which high-order EPs are formed for designing broadband, maximally flat, optical filters. By selecting the coupling coefficients between the resonators accordingly we show the bandwidth of such coupled cavity filters cannot only be enhanced substantially compared to other common design approaches, but also provide flat spectral response where these design approaches fail completely.

Beam Management in Millimeter-Wave Communications for 5G and Beyond

Massive MIMO is one of the promising techniques to improve spectral efficiency and network performance for reaching its targeted multi-gigabit throughput in 5G systems. For 5G New Radio (NR) systems, one of the key differences compared to 4G systems is the utilization of high frequency millimeter wave (mmWave) bands in addition to sub-6GHz bands. To keep the complexity and implementation cost low, hybrid analog-digital beam-forming with large-scale antenna array has become a common design approach to address the issue of higher propagation loss as well as to improve spectral efficiency in mmWave communication in 5G NR. The 5G NR standard is designed to adapt to different beam-forming architecture and deployment scenarios. This paper provides the overview on beam management procedure according to the current 5G standardization progress. We discuss some major challenges of millimeter-wave communications encountered in the current 5G NR standard and present some expected enhancements considered for the future beyond-5G standard.

Approximate Adder Implementation using Quantum- Dot Cellular Automata for Digital Signal Processing

We explore quantum-dot cellular automata (QCA) design for approximate computing units in digital signal processors. For this cause, a common approach for design is introduced, and approximation-oriented mirror adders (AMA) are developed. In this work, we compromise power/area efficiency of circuit-level design with accuracy supervision. We compare Approximate Mirror Adder cells designed using conventional CMOS technique and using QCA. Our technique picks fairly accurate adder designs that minimalize the over-all area, hitherto maintaining the ultimate performance by studying their error resilience.

Sensing Magnetic Fields With Surface Acoustic Wave (SAW) Sensors

Magnetic sensors are essential sensing elements in various industrial applications, but the design and technology used in the development of these sensors vary from application to application. Recently Surface Acoustic Wave (SAW) sensors have gained considerable attention due to their advantages over conventional sensors. SAW sensors are a class of Microelectromechanical (MEMS) system that use SAW technology and can be easily configured to sense physical parameters including magnetic fields. This paper presents an overview of recent research in the domain of magnetic field sensing based on such SAW devices. The paper describes the most common design approaches in practice and also discusses the key properties of fabrication materials for optimum design and performance. A short review of the processes involved in the development of SAW magnetic sensors is also covered in this paper.

On the Optimization of a Class-E Power Amplifier With GaN HEMTs at Megahertz Operation

Class-E power amplifiers have regained academic interest over the past decades due to the introduction of new high-performance wide-bandgap semiconductor devices and the increasing demand for high-efficiency power amplifiers. While these power devices, notably GaN HEMTs, have exceptional performance at megahertz operation, they also display an additional loss component due to $C_{{\rm oss}}$ at this frequency. Unfortunately, the dependence of this loss term on the peak voltage and the device size is the opposite of that of the conduction loss. In this article, we mathematically analyze the operation of a Class-E amplifier to find the optimal input voltage and device sizing where the sum of these two losses is minimized. From this analysis, we have found that the common design approach of maximizing device voltage rating and area to get the best efficiency no longer holds for some operating conditions. Furthermore, we examine the constraints that dictate when this optimization equations can and cannot be used, as well as propose a distributed loss model for the $C_{{\rm oss}}$ loss based on a generalized Steinmetz equation (GSE) to allow this new loss term to be easily simulated. To verify our mathematical analysis and to demonstrate the applications of the proposed GSE-based $C_{{\rm oss}}$ loss model, two design examples are provided. They consist of a choke-input Class-E amplifier at 10 MHz and a variable-resistance Class-E amplifier at 40.68 MHz. The experimental results on these two design examples show good agreements with our analysis.

Shellfish Aquaculture Map Viewers: An Assessment of Design, Data, and Functions to Inform Planning and Siting in the United States

Shellfish aquaculture in the United States contributes to the global seafood supply, provides habitat and restoration opportunities, and enhances the economic sustainability of coastal communities. Most marine aquaculture production (two-thirds by value) in the United States comprises bivalve shellfish (oysters, clams, and mussels). As the marine aquaculture footprint grows, so too does the potential for negative environmental and space–use interactions. To streamline shellfish aquaculture permitting, many states have developed web-based aquaculture map viewers to communicate critical regulatory, space–use, and natural resource information. In this study, 18 state-level shellfish aquaculture map viewers were reviewed for common design approaches, important data considerations, and useful tools and functions. Key characteristics of a successful shellfish aquaculture map viewer include a user-friendly interface, instructional guidance, the ability to assess both opportunity and risk, inclusion of authoritative data, and a long-term maintenance plan for the viewer and data. The most common design approaches reviewed were Esri Web AppBuilder and Google. Viewers ranged from having 3–27 layers, with “view orthoimagery” (94%) as the most commonly occurring function. This review provides valuable information on using map viewers and technological innovation to communicate shellfish aquaculture planning and permitting information to a variety of stakeholders.

Determination of the Hole-flangeability for thin Sheets

Sheet metal stretching is one of the most frequently applied sheets forming operation in the industry. Hole flanging is a common sheet forming operation to produce structural sheet metal components. Flanges are used for appearance, rigidity, hidden joints, and strengthening of the edge of sheet metal parts. Trial-end-error is the most common approach for tooling and process design in flanging operations. This paper presents some experimental results of hole-flanging process performed on flat deep drawing steel sheets with circular hole drilled or punched in the centre of blank. Three punches of different geometry i.e. cylindrical, hemispherical and conical were used in this experiment. The effect of both the punch geometry and material mechanical parameters (especially strain hardening and plastic anisotropy) on the limit expansion of the hole, limit strain dependence on hole performing technology as well as sheet thickness distribution along collar formed was determined.

Model of fragmentation distribution over a protective wall

This paper presents an analysis of perforated witness plates that were part of an experimental setup of previously published field tests. The witness plates were placed in the field tests to check the fragmentation pattern of the cased charge. A qualitative inspection of the plates shows that the spatial mass distribution of the fragments was not uniform over the wall height, and that it was characterized by an intense strip, which was stricken by a high magnitude of the fragmentation mass. Image analysis of the post-test plate pictures indicated that a previously suggested model for the intense strip geometry and fragmentation mass ratio under-predicts these parameters for increased standoff distances. Consequently, the paper presents an updated, enhanced version of the model, which considers the variation of the fragmentation Taylor angle along the charge and leads to a thicker intense strip. The updated model parameters were chosen in accordance with the analyzed experimental results and they were further verified with image analyses from additional published experimental data.The enhanced intense-strip model presented here can be used for global consideration of the fragmentation loading over a wall they strike. Furthermore, it should be emphasized that contrary to the common design approach, which assumes uniform damage and/or loading of the fragments, this model provides a useful tool for a realistic evaluation of the structural response of a protective wall, which is subjected to the combined loading of blast and fragments.

A scoping review of the problems and solutions associated with contamination in trials of complex interventions in mental health

BackgroundIn a randomised controlled trial, contamination is defined as the receipt of active intervention amongst participants in the control arm. This review assessed the processes leading to contamination, its typical quantity, methods used to mitigate it, and impact of use of cluster randomisation to prevent it on study findings in trials of complex interventions in mental health.MethodsThis is a scoping review of trial design approaches and methods of study conduct to address contamination. Studies included were randomised controlled trials of complex interventions in mental health that described the process leading to, amount of, or solution used to counter contamination. The Medline, Embase, and PsycInfo databases were searched for trials published between 2000 and 2015. Risk of bias was assessed using the Jadad score and domains recommended by Cochrane plus some relevant to cluster randomised trials.ResultsTwo hundred and thirty-four articles were included in the review. The main processes that led to contamination were health professionals delivering both active and comparator treatments and communication among clinicians and participants from the different trial arms. Twenty-three trials (10%) measured binary treatment receipt in the control arm with median 13% of participants found to be contaminated (IQR 5–33%). The most common design approach for dealing with contamination was the use of cluster randomisation (n = 93). In addition, many researchers used simple trial conduct methods to minimise contamination due to suspected contamination processes, such as organising for each clinician to provide only one treatment and separating trial arms spatially or temporally. There was little evidence for a relationship between cluster randomisation to avoid contamination and size of treatment effect estimate.ConclusionThere was some evidence of modest levels of treatment contamination with a large range, although a minority of studies reported the amount of contamination. A limitation was that many trials described the problem in little detail. Overall there is a need for greater measurement and reporting of treatment receipt in the control arm of trials. Researchers should be aware of trial conduct methods that can be used to minimise contamination without resorting to cluster randomisation.

An Approach to Improve Energy and Cost Performance of a Social Housing Archetype in Cold Climate Region

The importance of building energy performance has been substantially increasing in the last decades due to the global warming. Therefore, buildings within the existing stock and the new buildings are encouraged to achieve the energy performance restrictions and efficiency levels. In this context, a social housing archetype (Harct), which is constructed in each climate region of Turkey with a common design approach for temperate climate region, is evaluated as a base case to improve the energy performance for the cold climate region by the optimization of the life cycle cost (LCC). It is, namely, aimed to not only improve the energy performance of the archetype but also to ensure optimal cost efficiency as significant criterion. It is focused to optimize the façades of the Harct in terms of window width, and optic and thermo-physical properties of the façade with determining the efficient insulation thickness level for exterior walls and efficient glazing types for windows. Firstly, façade design is analysed to find out the minimum and maximum windows’ widths to achieve the optimal window sizes. Secondly, optic and thermo-physical properties and cost data of the opaque and transparent façade elements have been designated among the market products in accordance with the current regulations. Energy model of the building has been run by Energy Plus simulation tool, in order to integrate it with GenOpt for optimization. Optimization was performed to carry out efficient frontier cases. The results were evaluated from life cycle cost (LCC) and energy efficiency point of view to highlight the cost optimal point

Development of Positron Emission Tomography Radiotracers for the GABA Transporter 1.

In vivo positron emission tomography (PET) imaging of the γ-aminobutyric acid (GABA) receptor complex has been accomplished using radiolabeled benzodiazepine derivatives, but development of specific presynaptic radioligands targeting the neuronal membrane GABA transporter type 1 (GAT-1) has been less successful. The availability of new structure-activity studies of GAT-1 inhibitors and the introduction of a GAT-1 inhibitor (tiagabine, Gabatril) into clinical use prompted us to reinvestigate the syntheses of PET ligands for this transporter. Initial synthesis and rodent PET studies of N-[11C]methylnipecotic acid confirmed the low brain uptake of that small and polar molecule. The common design approach to improve blood-brain barrier permeability of GAT-1 inhibitors is the attachment of a large lipophilic substituent. We selected an unsymmetrical bis-aromatic residue attached to the ring nitrogen by a vinyl ether spacer from a series recently reported by Wanner and coworkers. Nucleophilic aromatic substitution of an aryl chloride precursor with [18F]fluoride was used to prepare the desired candidate radiotracer ( R, E/ Z)-1-(2-((4-fluoro-2-(4-[18F]fluorobenzoyl)styryl)oxy)ethyl)piperidine-3-carboxylic acid (( R, E/ Z)-[18F]10). PET studies in rats showed no brain uptake, which was not altered by pretreatment of animals with the P-glycoprotein inhibitor cyclosporine A, indicating efflux by Pgp was not responsible. Subsequent PET imaging studies of ( R, E/ Z)-[18F]10 in rhesus monkey brain showed very low brain uptake. Finally, to test if the free carboxylic acid group was the likely cause of poor brain uptake, PET studies were done using the ethyl ester derivative of ( R, E/ Z)-[18F]10. Rapid and significant monkey brain uptake of the ester was observed, followed by a slow washout over 90 min. The blood-brain barrier permeability of the ester supports a hypothesis that the free acid function limits brain uptake of nipecotic acid-based GAT-1 radioligands, and future radiotracer efforts should investigate the use of carboxylic acid bioisosteres.

DESIGN PARTICIPATION: FROM RHETORIC TO PRACTICE (AND BACK?)

<jats:p>Design participation is considered an inclusive, democratic and transparent process of urban planning and decision-making, particularly important for environments where complex social and economic realms could easily be misinterpreted in a common top-down design approach. This paper examines actual contributions of this methodology, implemented in ongoing strategies for designing and building public spaces and cultural infrastructure as part of the project Novi Sad European Capital of Culture 2021, which is based on democracy, decentralisation, inclusion and citizens' participation. Now, these strategies were put into action, with several projects prepared, launched and brought closer to actual realisation. This process revealed conclusions inrespect to implementation possibilities, as well as its strengths and weaknesses in actual projects, and ephasized the need to further improve urban practice and undertake change of the slow and unprepared procedures of the City administration.</jats:p>

Introducing gear ratings and AGMA conversion factors for the steel spur gear design under bending fatigue

Abstract The design approaches are not rated for gear tooth volume, the designers are not aware of the loss or gain on the cost, and failure or success of the design. This study provides a novel method to rate and convert textbook gear design approaches into ANSI/AGMA standard. The steel pinions with lowest and highest strengths covering minimum and maximum strengths available for the gear design meshing with cast iron gear were used in order to ensure that the method presented is generic. The method relies on obtaining design data (module m (mm) and face width F (mm)) for the most common design approaches considering bending fatigue. The gear design approaches are rated for the loss or gain using dimensionless geometric rating numbers, and then dimensionless conversion factors are obtained. Mean values of conversion factors independent of input power for the desired speed ratio are used to derive correlation equations for converting the design results of the selected approach to ANSI/AGMA standard. The m...

Limitations of Traditional Capacity Equations for Long Curb Inlets

Recent work with full-scale experiments indicates that there are fundamental problems with standard curb inlet design equations when applied to depressed curb inlets of 10 ft (3 m) or longer. A full-scale laboratory experiment showed that the latter part of a long inlet does not have a simple linear water surface profile at 100% interception, which is assumed for the form of Izzard’s equation that is adopted for many common design approaches [including the Hydraulic Engineering Circular 22 (HEC-22) design equations recommended by FHWA]. For a long inlet, thin flow sheets were observed for a substantial portion of the inlet length, which is consistent with previous observations that have not been incorporated into standard design equations. Experimental results indicate that the HEC-22 design equations significantly overestimate the interception capacity of long, depressed curb inlets for an on-grade gutter. This issue has potential safety implications in that the gutter bypass and spread for a design storm will be larger than expected for such inlets. The present work is preliminary, so an L2 measure previously proposed by Izzard is recommended as a maximum inlet length pending the outcome of further studies.

A Novel Analytical Design Approach for Determining the Optimum Load to Minimize Harmonic Output Power Based on X-Parameters

In the last decades, several analytical approaches for linear RF modeling and design have been introduced. In general, using these approaches, source and load reflection coefficients are calculated for designing input and output matching networks. This reflection coefficient is set to achieve a specific target such as maximum output power and minimum noise or an intermediate condition. The most common linear design approach is the use of S-parameters. However, S-parameters cannot model the nonlinear behavior of amplifiers. Nonlinear RF systems such as power amplifiers are typically designed using nonlinear models and/or load-pull measurements. Recently, X-parameters have been presented to model nonlinear device behavior. In this paper, a new design approach based on X-parameters has been introduced and will be verified by simulations and experimental results. Also, it will be indicated that this method speeds up the design procedure when compared with the load-pull method. Using this approach, we can calculate the load reflection coefficient at the fundamental frequency for minimizing a specific harmonic output power. Finally, the application of this approach in minimizing a specific harmonic in the output signal and increasing the dynamic range of the amplifier will be investigated.

Rapid design optimization of antennas using variable-fidelity EM models and adjoint sensitivities

Purpose Development of techniques for expedited design optimization of complex and numerically expensive electromagnetic (EM) simulation models of antenna structures validated both numerically and experimentally. The paper aims to discuss these issues. Design/methodology/approach The optimization task is performed using a technique that combines gradient search with adjoint sensitivities, trust region framework, as well as EM simulation models with various levels of fidelity (coarse, medium and fine). Adaptive procedure for switching between the models of increasing accuracy in the course of the optimization process is implemented. Numerical and experimental case studies are provided to validate correctness of the design approach. Findings Appropriate combination of suitable design optimization algorithm embedded in a trust region framework, as well as model selection techniques, allows for considerable reduction of the antenna optimization cost compared to conventional methods. Research limitations/implications The study demonstrates feasibility of EM-simulation-driven design optimization of antennas at low computational cost. The presented techniques reach beyond the common design approaches based on direct optimization of EM models using conventional gradient-based or derivative-free methods, particularly in terms of reliability and reduction of the computational costs of the design processes. Originality/value Simulation-driven design optimization of contemporary antenna structures is very challenging when high-fidelity EM simulations are utilized for performance utilization of structure at hand. The proposed variable-fidelity optimization technique with adjoint sensitivity and trust regions permits rapid optimization of numerically demanding antenna designs (here, dielectric resonator antenna and compact monopole), which cannot be achieved when conventional methods are of use. The design cost of proposed strategy is up to 60 percent lower than direct optimization exploiting adjoint sensitivities. Experimental validation of the results is also provided.

Composite repairs to bridge steels demystified

This paper examines crack growth associated with carbon fibre reinforced plastic (CFRP) repairs to cracked bridge steels and boron epoxy composite and fibre metal patch repairs to cracked aluminium alloy structures. It is first shown that the da/dN versus ΔK curves associated with bridge steels is very similar to that seen in the high strength aerospace steel D6ac. The importance of 1st ply failure, which was first observed on a boron epoxy repair to the F-111 D6ac steel wing pivot fitting, and how to alleviate this failure mechanism is then discussed as is the common design approach whereby after patching the repair is designed to have a ΔK beneath the ASTM long crack threshold ΔKth. It is shown that crack growth in bridge steels repaired with CFRP patches and in aluminium alloy structures repaired with either boron epoxy or glare patches exhibit a near linear relationship between the log of the crack length and the number of cycles. We then show that crack growth in these repairs can be represented by the same simple master curve relationship that has been found to hold for cracks growing in both operational aircraft and full scale fatigue tests. These findings are important since they suggest that the methodology used by the Royal Australian Air Force to certify structural modifications to operational aircraft may also be applicable to composite repairs/modifications to steel bridges, which are generally experience significantly lower stresses.

The calibration of a prototype occluded ear simulator designed for neonatal hearing assessment applications.

An innovative family of ear simulators has been conceived for the calibration and traceability of audiometric equipment. Each device within the family has been designed for a particular key age group, covering neonates through to adults. The age-specific ear simulators are intended to improve the quality of hearing assessment measurements for all test subject age groups, and will be proposed as the next generation of standardised ear simulators for audiometric applications. The family of ear simulators shares a common design and modeling approach, and the first prototype devices for neonatal applications have been manufactured. The objectives of this study were to develop calibration methods, verify conformance to the design goals, demonstrate that the device is capable of being calibrated reliably, and show that its performance is ultimately suitable for international standardisation and eventual adoption into clinical practices. Four national measurement institutes took part in a round-robin calibration comparison and an analysis of the results showed that these objectives were achieved.