Flexible Design Process Research Articles

Theoretical Foundations of Designing for Darkness

This paper sketches the theoretical foundations of designing for darkness. Drawing from (lighting) design theory, philosophy of technology, and environmental ethics, it argues that we have an opportunity to re-examine the meaning and experiences of darkness, exploring why and how we should protect or re-introduce darkness into urban nightscapes – not as a constraint, but a constructive goal for urban lighting. It is further positioned as a formative, not prescriptive, framework: bounding and guiding a flexible design process, and able to inform different strategies and approaches. Framed in this way, three core principles are outlined that serve as moral and aesthetic goals for urban lighting. The first is aspirational, situating ‘darkening cities’ as a type of urban (ecological) restoration akin to greening cities. This requires seeing urban darkness as a critical natural infrastructure that can bring both material and social benefits. The second is evaluative, specifying the value-level design requirements to be fostered in urban nightscapes. Lighting strategies should, as a prima facie obligation, promote and preserve the values of darkness. The third principle is experiential, exploring how strategies can create the conditions for positive experiences of – and engagement with – urban darkness. In combination, they offer a means to specify darkness as a design requirement, as well as a reflexive tool to assess and refine the overarching theory of designing for darkness.

User involvement in the design of outdoor environments to support mental health recovery—From reflection to action

One out of eight people worldwide struggles with mental health illnesses. The treatment is slowly shifting from a biomedical perspective, primarily paying attention to symptom reduction and medicine, towards a more holistic and recovery-oriented perspective. At the same time research shows that the outdoor environment can help relieve pain and stress and improve mental well-being. The study presents a practice-oriented method, inspired by evidence-based design, for developing a master plan for two outdoor gardens at a Mental Health Center in the Capital Region of Denmark. We aimed to provide guidelines for how to set up and perform a flexible design process that combines established knowledge with the needs of the patients and staff. The empirical data were collected through a systematic literature review, semi-structured interviews with patients and staff, workshops and presentations at two different mental health units. The two case studies showed good results in involving patients and staff in the design process and based on the findings of our study involving users. In conclusion, it was apparent that the use of interdisciplinary collaboration informed the design outcome. Based on the two cases, the following advice can be given to the architectural profession: Architects should integrate interdisciplinary knowledge into the design process of outdoor facilities for people with special needs. Interdisciplinary knowledge and user involvement complement each other by adding important site-specific details from the user to the more general design guidelines. This way, the design becomes more nuanced and customized to the users of a specific site. The study showed how architects can import knowledge, skills and values from other disciplines such as environmental psychology to improve the decision-making process of future projects for the benefits of mental patients.

Corrosion behavior of selective laser melted 6061 aluminum alloy electrodes for aluminum-air battery

6061 aluminum alloy can be used as an anode for aluminum-air batteries. Compared with cast one, three-dimensional (3D) printed aluminum alloy shows more flexible design and production process. Moreover, the self-corrosion behavior of 3D printed aluminum alloy without grinding its surface layer in alkaline solutions (electrolyte for aluminum-air batteries) is unclear. Here, the comparison between 3D-printed and cast 6061 aluminum alloy is investigated by self-corrosion testing, potentiodynamic polarization, electrochemical impedance spectroscopy, and hydrogen bubble visualization experimentation. The results show that although the corrosion resistance of the 3D-printed 6061 aluminum alloy decreases rapidly with time, it exhibits higher corrosion resistance at the initial stage of corrosion than that of cast 6061 aluminum alloy due to the “fish scale” layer and may be able to improve its discharge performance. The surface microscopy analysis results are in good agreement with those of the self-corrosion test and electrochemical characteristics.

The Applications of Generative Adversarial Networks in Architecture Design: A Systematic Review

Purpose: To review and analyze the research status of the application of generative adversarial networks (GANs) in the field of architecture design. Methods: This study followed the latest PRISMA guidelines and systematically collected relevant research literature from domestic and international sources. In-depth analysis was conducted on 95 representative Chinese and English language articles. During the analysis process, three dimensions of intelligent architectural generation methods were comprehensively and deeply explored: the data application scale, algorithm type, and architectural design process. Results: (1) GANs have been applied to various processes in architectural design practice, from design generation, development, and evaluation to final solution expression; (2) GANs can be applied at different architectural scales, ranging from large-scale complex functional buildings to refined layout designs of residential units; (3) the appearance of GANs enables designers to quickly present design results at various stages, greatly improving work efficiency; and (4) at present, GANs also have many shortcomings, mainly reflected in the accuracy of the data and the usability of tools. Conclusion: Improvements in computer performance and the enrichment of data resources have promoted the widespread application of intelligent architectural generation methods. GANs have great potential in the field of architectural design and can provide a more efficient, flexible, and diverse design process. However, further research and development are needed to address the challenges and limitations of using GANs in this field.

Bayesian optimization algorithm based support vector regression analysis for estimation of resilient modulus of crushed rock materials for pavement design

The precise determination of the resilient modulus (MR) of the base and sub-base materials is a major preoccupation and a key criterion in the flexible pavement design process. The experimental determination of MR implies a challenging process which requires usually very difficult test procedures and extreme precautions and manpower. This is why soft computing techniques are increasingly popular and of growing importance. Many prediction techniques based primarily on linear and non-linear regression could not provide flexible use and consistent prediction of MR for practical engineering. This article introduces a hybrid of the Bayesian optimization algorithm (BOA) and support vector regression (SVR) as a new modelling tool for the MR prediction of crushed stone materials used as base and sub-base layers for pavement design. For this purpose, an experimental database was utilized to generate the hybrid BOA-SVR model of indirect estimation of the resilient modulus based on material type, basic engineering characteristics and loading conditions. The database consists of 260 experimental datasets obtained from repeated loading triaxial tests performed by the laboratory of the Central Transportation Agency located in Algiers, Algeria. To develop the model, all hyperparameters were optimised using the BOA technique. It was found that the average, median, standard deviation, minimum, maximum and interquartile range of the expected values of the developed hybrid model are very close to the experimental results. Results revealed that the hybrid BOA-SVR model predict the MR of the crushed stone materials with a coefficient of determination of 99.91% and root mean squared error of 3.55. Comparisons with traditional and other Artificial intelligence models showed that BOASVR hybrid model predictions are more accurate and robust than those of other models.

Computer modeling and software research of car and engine parts

Problem. The development of automotive technology for various purposes and the improvement of existing car models, requires a fast and flexible design process. Spatial models of details and nodes are the starting points for design, and the necessary design documentation is performed on their basis. When manufacturing parts on CNC machines, it is necessary to quickly obtain a control program that will increase the accuracy of the product by ensuring the optimal trajectory of the mutual movement of the part and the tool. Therefore, the creation of a comprehensive methodology for the design of car parts, their basic inspection and obtaining design documentation is an important technical task. Goal. The main goal of the work is to determine the rational sequence and basic principles of computer-aided design, research and manufacturing of car and engine parts, and the development of mathematical spatial models of surfaces in order to optimize control programs for CNC machines. Methodology. The approaches adopted in the work for solving the set goal are based on general design principles. The methods of conducting static and dynamic calculations, as well as spatial mathematical modeling of the processes of manufacturing parts were also used. Results. A comprehensive methodology for designing parts of engines and cars has been developed. The main principles of creating spatial models have been determined in order to achieve their flexibility and simple editing. Methods of automating the development of drawings and design documentation are described. The software options for the primary verification of static strength and frequency analysis are considered. A calculation program has been developed for constructing transient and amplitude-phase-frequency characteristics. The mathematical spatial modeling of typical surfaces of the camshaft is provided with the aim of further research and optimization of the development of a control program for processing on a CNC machine tool. Originality. The defined basic principles of designing parts of engines and cars provide an opportunity to create a flexible spatial model and more fully automate the process of drawing up technical documentation. The developed mathematical spatial models of the supporting and working surfaces of the camshaft make it possible to write a control program with the determination of the optimal trajectory of the mutual movement of the part and the tool. Practical value. The obtained results can be recommended when designing car parts and assemblies.

Distance between theory and practice in a project by Luigi Moretti, parametric architecture’s first theorist

Starting in the 1940s, Luigi Moretti was the first theorist of architettura parametrica, suggesting a novel scientific vision of architectural design. However, the contribution of this theory to his built projects appears limited and far from the rigour of the famous mathematical modelling he presented at the XII Triennale di Milano in 1960. Despite Moretti's attempts to spread parametric architecture internationally, the apparent distance between the theoretical dimension and the professional practice has led to a marginal recognition of his contributions to the developments of Computational Design and, more recently, Parametricism. Questioning how Moretti considered aspects of parametric architecture in his professional practice may reveal how he intended the relationship between theory and practice. This paper analyses the troubled design process of Moretti's Bonifacio VIII Baths in Fiuggi, Italy, a project that has never been studied as an application of parametric architecture despite having several attributes that are now associated with the origin of parametric design. The proposed position is that, along his rigid theory, Moretti developed more informal and flexible design processes. The analysis of compositional and methodological values behind the evolution of this project, its archival materials, and Moretti's design theories will be used to demonstrate the thesis.

Advances in Flexible Organic Photodetectors: Materials and Applications.

Future electronics will need to be mechanically flexible and stretchable in order to enable the development of lightweight and conformal applications. In contrast, photodetectors, an integral component of electronic devices, remain rigid, which prevents their integration into everyday life applications. In recent years, significant efforts have been made to overcome the limitations of conventional rigid photodetectors, particularly their low mechanical deformability. One of the most promising routes toward facilitating the fabrication of flexible photodetectors is to replace conventional optoelectronic materials with nanomaterials or organic materials that are intrinsically flexible. Compared with other functional materials, organic polymers and molecules have attracted more attention for photodetection applications due to their excellent photodetection performance, cost-effective solution-fabrication capability, flexible design, and adaptable manufacturing processes. This article comprehensively discusses recent advances in flexible organic photodetectors in terms of optoelectronic, mechanical properties, and hybridization with other material classes. Furthermore, flexible organic photodetector applications in health-monitoring sensors, X-ray detection, and imager devices have been surveyed.

Detecting logical relationships in mechanical, electrical, and plumbing (MEP) systems with BIM using graph matching

The increasingly complex design has gained difficulty in conducting the rule compliance checking for the Mechanical, Electrical and Plumbing (MEP) system in the design phase. Useful rule-checking systems could contribute to a quicker project delivery time. Currently, an efficient method for checking the logical relationship is still lacking. This study aims to propose an MEP rule checking framework using the subgraph matching technology. First, the MEP components in the BIM model are extracted by utilizing the application programming interface (API), and a graph database is established with point-based and curve-based instances being nodes and relationships, respectively. Second, the graph database is simplified to increase the speed of graph matching. Third, the rules, which regulate how the MEP components should be connected, are represented by a knowledge graph. Finally, rule checking is achieved by comparing the graph database against the knowledge graph, and the critical path in a sub-system is detected by calculating the betweenness centrality. A case study with a rail station is used to evaluate the approach where the overall model checking and rule checking are conducted on the original and simplified graph databases sequentially. The results show that the proposed approach could achieve the rule compliance checking at a high speed, and 6 unconnected instances along with 155 problematic pipe fittings have been found. Besides, the critical path for the selected ACS system is from the water-cooled chiller to the condenser water pump. The proposed framework could help in the overall model checking and rule checking process, improving the efficiency of BIM engineers. This research demonstrates that converting a BIM model into a graph database can benefit conventional BIM analysis methods by incorporating advanced technologies (e.g., artificial intelligence) to enable a more flexible and accurate MEP design process.

Design of Robust Capacitive Power Transfer Systems Using High-Frequency Resonant Inverters

This article presents a novel approach using a resonant inverter operating at 6.78 MHz for a robust capacitive power transfer (CPT) system with a small air gap. The flexible design process of a class <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\Phi _2$</tex-math></inline-formula> inverter to select the capacitance in the load network allows us to maintain high efficiency without a compensation inductor to mitigate misalignments between coupling plates. The capacitor in the class <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\Phi _2$</tex-math></inline-formula> inverter can be any value above 3 nF at megahertzs frequencies because it is not in resonance but provides dc blocking. If the capacitance value varies in the range above 3 nF, it does not affect the performance of the inverter and the CPT system. We design a push–pull class <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\Phi _2$</tex-math></inline-formula> inverter to provide isolation between the transmitting and receiving sides by nature and easily increase the output power twice. In addition, compared with the previous CPT system, the proposed inverter can increase the output power, while the misalignment between coupling plates increases because of the nonresonant load network. The designed coupling capacitor with a Kapton film has a capacitance value above 4.6 nF, even with a 15-cm misalignment. We also simulate the design in Ansys Maxwell HFSS to examine the electric fields. We present simulated and experimental measurements of the push–pull class <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\Phi _2$</tex-math></inline-formula> inverter with the designed coupling capacitor. The system’s nominal output power was 277 W with a 86.65% efficiency at an input voltage of 50 V. With the misalignments up to 15 cm, the efficiency is almost constant, 87% (80% at dc-to-dc CPT system), while the capacitance of the coupling plates varies from 8.82 to 4.62 nF.

Squaring a Circle: To What Extent Are Traditional Circuit Analogies Impeding Synthetic Biology?

Synthetic biology has been significantly shaped by modular design principles through analogies to electrical and computer engineering. Although convenient, these parallels often break down in practice, and we are still largely unable to engineer sophisticated systems that behave as predicted. As nature has achieved robust and intricate programs without requiring strict modularity, we may want to revisit genetic circuit design approaches. Rather than pursuing modularity, we could aim for a robust and scalable design framework that embraces the uncertainty that context dependence brings to engineering in a biological chassis. Systems and control theory offer a starting point, but a substantial conceptual leap will be needed to quantitatively predict system behavior and establish flexible context-aware design processes. Only by overcoming these hurdles shall we be able to capitalize on synthetic biology in particular—and on biotechnology in general—for medicine, environmental engineering, and energy production.

Stringent Base Specific and Optimization-Free Multiplex Mediator Probe ddPCR for the Quantification of Point Mutations in Circulating Tumor DNA.

Simple SummaryCancer treatment strategies and their follow-up monitoring are changing to personalized therapies, based on molecular genetic information from the individual person. Liquid biopsy, where this molecular information is derived from body fluids such as blood, has the potential to provide a systemic fingerprint of cancer dynamics, and, compared to tissue biopsy, is much less invasive for the patient. We used the previously published mediator probe PCR technology for liquid biopsy detection of several mutations in one reaction, so-called digital multiplex PCR. Quantification of point mutations in plasma eluates from follow-up patients using 4-plex digital assays showed a comparable performance to reference 2-plex assays. As a key feature, the presented multiplex assays require no laborious optimization as they use the same concentrations and cycling conditions for all targets. This allows for flexible design and interchangeable target panels, thus the assay is easily adaptable for individual patient monitoring and reduces sample consumption.There is an increasing demand for optimization-free multiplex assays to rapidly establish comprehensive target panels for cancer monitoring by liquid biopsy. We present the mediator probe (MP) PCR for the quantification of the seven most frequent point mutations and corresponding wild types (KRAS and BRAF) in colorectal carcinoma. Standardized parameters for the digital assay were derived using design of experiments. Without further optimization, the limit of detection (LoD) was determined through spiking experiments with synthetic mutant DNA in human genomic DNA. The limit of blank (LoB) was measured in cfDNA plasma eluates from healthy volunteers. The 2-plex and 4-plex MP ddPCR assays showed a LoB of 0 copies/mL except for 4-plex KRAS G13D (9.82 copies/mL) and 4-plex BRAF V600E (16.29 copies/mL) and allele frequencies of 0.004% ≤ LoD ≤ 0.38% with R2 ≥ 0.98. The quantification of point mutations in patient plasma eluates (18 patients) during follow-up using the 4-plex MP ddPCR showed a comparable performance to the reference assays. The presented multiplex assays need no laborious optimization, as they use the same concentrations and cycling conditions for all targets. This facilitates assay certification, allows a fast and flexible design process, and is thus easily adaptable for individual patient monitoring.

Parametric design applied to die cutting machine

In this paper, the particularities of applying parameterization in industrial machines corresponding to the manufacturing area are exposed and analyzed. For its development, the parameterized design of a die cutting machine is proposed as an object of study, which is formulated from the main elements considered of importance in the principle of operation, being necessary to carry out a prior investigation to analyze it and how the parameterization process influences. Parameterization is a quality of the components to adapt flexibly to the needs of the industry or sector, facilitating the redesign and manufacturing process, allowing the desired dimensional update or adjustment to be carried out only to the central component and the others are automatically adapted. Attending to the current needs and trends of the fourth industrial revolution, as well as establishing the benefits of this type of flexible design processes to expand their implementation to different industrial machines such as robot configurations.

How societal expectations, new digital tools, andthe COVID crisis are driving a step-change in human centric remediation.

How societal expectations, new digital tools, andthe COVID crisis are driving a step-change in human centric remediation.

Broadband Equal-Split Directional Couplers Composed of Cascade- and Tandem-Connected Coupled-Line Sections Having Unequal Lengths

A new concept of broadband equal-split coupled-line directional couplers is proposed. The proposed couplers are based on coupled-line sections, all having the same coupling coefficient, and feature frequency characteristics similar to the ones obtained for classic symmetrical three-section coupled-line couplers. It is shown that appropriate cascade- and tandem-connected coupled-line sections, having all the same coupling coefficients and different electrical lengths allow for achieving equal power split in a broadband frequency range together with the quadrature differential phase response. Therefore, a very flexible design process is possible, in which directional couplers with different bandwidths and coupling imbalances can be realized by changing solely the electrical lengths of the coupled-line sections. Moreover, the proposed networks require significantly lower coupling coefficients and feature slightly shorter overall electrical lengths than their classic counterparts. The theoretical analysis of the proposed circuits is shown in the paper and is followed by the design and measurements of two broadband equal-split quadrature directional couplers operating at the center frequency of 2 GHz.

3D printing of ceramic cellular structures for potential nuclear fusion application

A flexible and integrated design and manufacturing process based on photopolymerization DLP 3D printing technology is proposed to fabricate tritium breeder units that can be used in fusion reactors. Defect-free cellular structures of lithium-enriched Li4SiO4 is manufactured for the first time that can be used to replace the traditional pebble beds configuration to overcome problems resulted from stress concentration and difficulty in packing fraction improvement. As-received large Li4SiO4 powder which is highly sensitive to air and ambient environment is protected and processed in inert glove box for the use in the preparation and optimization of stable photopolymerizable resin-based ceramic slurry suitable for DLP 3D printing. Appropriate debinding and sintering treatments applied result in homogeneous shrinkage and preserved features of the cellular structures, showing benefits for dimension control. The intact structures possess high phase purity and suitable and tailorable effective ‘packing fraction’ for breeding application. Mechanical tests and the obtained results compared with existing works further confirm that the cellular parts prepared in this work have advantageous performance. The unique advantage of flexible control in design and manufacturing of 3D printing may pave a promising way for greater possibilities to engineer novel tailored high-performance tritium breeder structures used in nuclear fusion technology.

Experimental and Field Investigation of Road Mesh Reinforcement in Flexible Pavements

The most acceptable combination of layer thickness and types of materials used in the different layers of pavement along with an estimated traffic to be carried, during the service life of the pavement, complete the flexible pavement design process. In addition to satisfying the tolerable criteria for fatigue and rutting mechanisms, the pavements are subjected to much higher load intensities than that of the estimated traffic during design. This increases the importance of maintaining the quality of base layer materials as base layer plays a major role in maintaining the performance of unpaved roads. Due to the absence of confinement in the lateral direction, there is a possibility of permanent deformation when a vertical load is applied. To restrict both resilient and permanent deformations, it is essential to consider geosynthetic reinforcement in pavement engineering. The use of road mesh manufactured from double twisted steel wire mesh is studied as a possible reinforcement material for carrying the increased traffic loads, and experiments are conducted in this direction. The primary objective of this study is to reduce the thickness of the base layer and to improve the performance of the base layer under heavy loading conditions. Static and repeated plate load tests were conducted on unreinforced as well as road mesh-reinforced base layer. The results of the experimental studies showed better performance of road mesh-reinforced base layer by reducing the permanent deformations. The improvement in the performance of reinforced sections was also measured in terms of resilient deformation and predicted resilient modulus from resilient deformations. The studies also include the role of reinforcement in improving the pressure distribution in the base layer and the pressure above the subgrade level in terms of stress distribution angle. The improved performance of reinforced sections was reflected in the field studies by conducting FWD tests and calculating LCR from those results.

A Framework for Formal Verification of Behavior Trees With Linear Temporal Logic

Despite the current increasing popularity of Behavior Trees (BTs) in the robotics community, there does not currently exist a method to formally verify their correctness without compromising their most valuable traits: modularity, flexibility and reusability. In this letter we present a new mathematical framework in which we formally express Behavior Trees in Linear Temporal Logic (LTL). We show how this framework equivalently represents classical BTs. Then we utilize the proposed framework to construct an algorithm to verify that a given BT satisfies a given LTL specification. We prove that this algorithm is sound. Importantly, we prove that this method does not compromise the flexible design process of BTs, i.e. changes to subtrees can be verified separately and their combination can be assured to be correct. We present an example of the proposed algorithm in use.

Multi-resonance and ultra-wideband terahertz metasurface absorber based on micro-template-assisted self-assembly method.

As a promising platform for multi-functional terahertz devices, metasurface absorbers have received widespread attention in recent years. However, due to the existence of manufacturing difficulties, high cost, fragility, single or narrow absorption and other disadvantages, their application ranges are severely limited. Therefore, to effectively solve these problems, we have designed a flexible and high-precision terahertz metasurface absorber based on the micro-template assisted self-assembly method. Free from high cost, complicated process and time-consumption, the sandwich structure terahertz metasurface absorber consisting of a ceramic microspheres layer, a dielectric spacer layer, and a metal copper film is fabricated economically. On the one hand, through assembling the microspheres on the dielectric spacer in a periodic pattern arrangement, multiple resonances can be observed with a maximum absorption rate of up to 92.5% at 0.745 THz and are insensitive to the polarization of incident light. On the other hand, by attaching the microspheres to the dielectric layer in a compact configuration, 90% absorption bandwidth beyond 1.2 THz can be observed with a central frequency of 1.8 THz. The theoretical model of multiple reflection and interference is employed to explain these absorption characteristics. Considering the flexible design and high-throughput manufacturing processes, this work provides a promising platform for the development of high-efficiency and multi-functional terahertz devices.

Development of the Snapshot Method for Six Degree-of-Freedom Flight Dynamics Simulation of a High Aspect Ratio Wing Aircraft

The purpose of this paper is to develop a six degree-of-freedom flight simulation while considering the flexibility of an aircraft with high aspect ratio wings using by new quasi-steady temporal coupling scheme named ‘snapshot method’. The simulation was based on the quasi-steady temporal coupling scheme for the flow field, elastic structure, and rigid body motion problem. A full three-dimensional finite-element model of unmanned aerial vehicles was used. The object aircraft has main wings with an aspect ratio over 20 and a flight for long endurance in high altitude. To consider the flexibility of these aircraft, the present snapshot method was developed that combines ‘aerodynamic—structural dynamics—flight dynamics’ to analyze dynamic response. By applying this method, MATLAB/SIMULINK, which analyzes the rigid body motion, and MSC FlightLoads, which is responsible for aeroelastic trim analysis, was tightly linked into the present simulation framework. Using the present simulation, aircraft response under various maneuver conditions was simulated. First, the trim analysis for the level cruise was performed. Trim parameters, stability derivative coefficients, and the moment of inertia were also determined. Based on these results, the flight dynamics of the aircraft was simulated according to the operation of the rudder and the aileron control surface. The effect of the rigid and flexible body assumptions was also confirmed. In addition, these results were compared with other existing simulation results based on the multibody dynamics under the same conditions. To predict the response of the aircraft under the gust, the simulation was performed by applying the two-dimensional 1-cosine discrete gust profile. The important aspects, such as numerical prediction methods during stages of the highly flexible aircraft design process for a countermeasure to various challenging problems, were shown.