Alternative Design Method Research Articles

Multi-Objective Optimization of a Folding Kinetic Facade System Proposal for Thermal, Daylight, and Energy Performances

Efficient utilization of daylight and energy resources significantly influences the quality of indoor spaces, user comfort, and overall efficiency. This study presents a folding facade proposal through the design alternatives offered by kinetic architecture and parametric design to enhance efficiency. This alternative design method integrates and coordinates the design components simultaneously and makes any intervention easier when compared with traditional design methods. In this context, the method is based on computational models, aiming to find the most efficient design alternative by optimization. The proposed facade design specifically targets an indoor office space within a university. The modular system, integrated into existing windows, facilitates a folding movement. This dynamic feature aims to optimize illumination within the space, effectively controlling daylight without causing disruptions to users. Simultaneously, the design seeks to balance energy consumption and ensure thermal comfort. The results show that it provides a significant improvement over the base case. The proposed kinetic façade system improved indoor thermal comfort by 22.09-31.99% while slightly increasing energy use (2% at most). Although it provided an average of 59% improvement in spatial Daylight Autonomy (sDA), 13.30% - 87.38% was achieved compared to the base case. However, the desired value by LEED was achieved very little in Annual Sunlight Exposure (ASE). In conclusion, the proposed kinetic facade system proves to be a valuable intervention for enhancing the indoor environment of an office space at Dokuz Eylül University

Variable Duration Trial as an Alternative Design for Continuous Endpoints.

Clinical trials with continuous primary endpoints typically measure outcomes at baseline, at a fixed timepoint (denoted Tmin), and at intermediate timepoints. The analysis is commonly performed using the mixed model repeated measures method. It is sometimes expected that the effect size will be larger with follow-up longer than Tmin. But extending the follow-up for all patients delays trial completion. We propose an alternative trial design and analysis method that potentially increases statistical power without extending the trial duration or increasing the sample size. We propose following the last enrolled patient until Tmin, with earlier enrollees having variable follow-up durations up to a maximum of Tmax. The sample size at Tmax will be smaller than at Tmin, and due to staggered enrollment, data missing at Tmax will be missing completely at random. For analysis, we propose an alpha-adjusted procedure based on the smaller of the p values at Tmin and Tmax, termed . This approach can provide the highest power when the powers at Tmin and Tmax are similar. If the power at Tmin and Tmax differ significantly, the power of is modestly reduced compared with the larger of the two powers. Rare disease trials, due to the limited size of the patient population, may benefit the most with this design.

The benefits and challenges of artificial intelligence image generators for architectural ideation: Study of an alternative human-machine co-creation exchange based on sketch recognition

This paper deals with creative co-design between human and machine. It presents an alternative design method based on an emerging technology of sketch interpretation to support co-creation and collaborative creativity in architecture. This technology embraces spontaneity in design by generating inspirational images linked to the architect’s sketches. Our research aims to determine the benefits and challenges of this alternative instrumentation. We are developing a Wizard of Oz test method by immersing several designers in a studio instrumented by this human-machine co-creation technology. We analyze quantitatively and qualitatively the single-designer ideation activity of these subjects. We then investigate the integration of this co-creation instrumentation within the framework of a team design involving several architects. This confirms known benefits such as speeding-up and freeing-up of ideation and highlights the need for designers to evaluate sketched ideas by means of images simulating their real-life rendering, as well as the need for inspiration to materialize the premises of ideas that are still vague.

Experimental and numerical investigations of high-strength cold-formed steel multi-limb built-up section columns

This paper investigates the buckling behaviour and load-carrying capacity of G550 high-strength cold-formed steel multi-limb built-up section columns under axial compression. Each built-up section consists of multiple lipped and unlipped channel sections connected by self-tapping screws. The C3U1 section is formed by three C-sections (i.e. lipped channel section) and one U-section (i.e. unlipped channel section), while the C2U2 section is formed by two C-sections and two U-sections. The experimental programme involved tensile coupon tests, measurements of initial geometrical imperfection, and column tests on ten C3U1 and ten C2U2 multi-limb built-up section columns. The numerical modelling programme was then performed, with the nonlinear finite element models created and validated against the experimental results. The applicability of the codified Effective Width Method and Direct Strength Method for predicting the strengths of G550 high-strength cold-formed steel multi-limb built-up section columns, as specified in the American Specification and Australian Standard, was then evaluated. The evaluation results showed that the codified Effective Width Method led to rather conservative and less accurate failure load predictions for G550 high-strength cold-formed steel multi-limb built-up section columns, while the codified Direct Strength Method provided accurate and consistent failure load predictions and thus applicable to the design of G550 high-strength cold-formed steel multi-limb built-up section columns. Concerning the lack of design guidelines specifically for multi-limb built-up sections, a modified Direct Strength Method was thus proposed as an alternative design method and shown to provide accurate failure load predictions.

Wideband dual‐polarized rasorber design with genetic algorithm synthesis

AbstractIn this letter, an 11 GHz centered wideband absorptive frequency selective surface (FSS) design is presented. The absorptive FSS is dual polarized, and it has wide transmission band and a wide absorption band at the lower frequency side of the transmission band. An octagon shape with parallel microstrips toward center connected with lumped element resistors at the edges is proposed for the resistive layer unit element. Also, a multilayer octagon patch and aperture resonator are proposed for the wideband bandpass layer. As an alternative design method, the unit element of resistive layer of absorptive FSS is synthesized by a genetic algorithm code successfully. Genetic algorithm synthesis provides straightforward synthesis process compared to conventional method. Designed absorptive FSS is manufactured and frequency response is measured with WR‐90 waveguide setup. The measurement result of 1 dB transmission bandwidth is between 9.43 and 12.50 GHz with a minimum insertion loss of 0.65 dB.

Optimal design of a gravitational wave telescope system for the suppression of stray light.

For gravitational wave detection, the telescope is required to have an ultra-low wavefront error and ultra-high signal-to-noise ratio, where the power of the stray light should be controlled on the order of less than 10-10. In this work, we propose an alternative stray light suppression method for the optical design of an off-axis telescope with four mirrors by carefully considering the optimal optical paths. The method includes three steps. First, in the period of the optical design, the stray light caused by the tertiary mirror and the quaternary mirror is suppressed by increasing the angle formed by the optical axes of the tertiary mirror and the quaternary mirror and reducing the radius of curvature of the quaternary mirror as much as possible to make sure the optical system provides a beam quality with a wavefront error less than λ/80. Next, the stray light could satisfy the requirement of the order of 10-10 when the level of roughness reaches 0.2nm, and the pollution of mirrors is controlled at the level of CL100. Finally, traditional stray light suppression methods should also be applied to mechanics, including the use of the optical barrier, baffle tube, and black paint. It can be seen that the field stop can efficiently reduce stray light caused by the secondary mirror by more than 55% in the full field of view. The baffle tube mounted on the position of the exit pupil can reduce the overall stray light energy by 5%, and the difference between the ideal absorber (absorption coefficient is 100%) and the actual black paint (absorption coefficient is 90%) is 3.2%. These simulation results are confirmed by the Monte Carlo method for a stray light analysis. Based on the above results, one can conclude that the geometry structure of the optical design, the quality of mirrors, and the light barrier can greatly improve the stray light suppression ability of the optical system, which is vital when developing a gravitational wave telescope with ultra-low stray light energy.

Evaluating protection against lightning for historical buildings and cultural heritage monuments

A review on the lightning risk management and lightning protection of historical buildings and cultural heritage monuments is presented. Cases of lightning-related damages to historical monuments worldwide are presented with emphasis given to cases in Greece. Recorded incidents stress the need for an effective lightning protection system (LPS) design, ensuring sufficient protection of the monument against lightning, including its installations and contents, as well as persons. External LPS of several monuments and historical buildings worldwide are also presented. An external LPS has been designed for the Parthenon monument in Greece in accordance with IEC 62305. The LPS design has been evaluated based on a stochastic lightning attachment model. Revisions to the risk management of IEC 62305 with special focus on historical buildings and cultural heritage monuments are suggested. As this special category of structures is most commonly subject to constraints with respect to aesthetic intervention and construction, dedicated studies employing alternative methods for LPS design, based however on physical grounds, are required.

Quaternization drives spleen-to-lung tropism conversion for mRNA-loaded lipid-like nanoassemblies.

Background: As the overwhelming majority of advanced mRNA delivery systems are preferentially accumulated in the liver, there is an accelerating growth in the demand for the development of non-liver mRNA delivery platforms. Methods: In this study, we prepared cationic lipid-like nanoassemblies through a N-quaternizing strategy. Their physicochemical properties, in vitro mRNA delivery efficiency, and organ tropism in mice were investigated. Results: Introduction of quaternary ammonium groups onto lipid-like nanoassemblies not only enhances their mRNA delivery performance in vitro, but also completely alters their tropism from the spleen to the lung after intravenous administration in mice. Quaternized lipid-like nanoassemblies exhibit ultra-high specificity to the lung and are predominantly taken up by pulmonary immune cells, leading to over 95% of exogenous mRNA translation in the lungs. Such mRNA delivery carriers are stable even after more than one-year storage at ambient temperature. Conclusions: Quaternization provides an alternative method for design of new lung-targeted mRNA delivery systems without incorporation of targeting ligands, which should extend the therapeutic applicability of mRNA to lung diseases.

O.I.C.-based design of extruded and welded aluminum I-sections

Current standards rely on simplified approaches to predict the resistance of aluminum structural elements that can be shown to inadequately account for the effects of strain hardening, instabilities, and heat reduced properties. This paper summarizes investigations towards the development of an alternative design method for aluminum open cross-sections, based on the Overall Interaction Concept (O.I.C.). This innovative design approach relies on the interaction between resistance and stability, and also allows to consider geometrical and material imperfections. Moreover, it allows to obtain direct, precise and consistent resistance predictions using continuous buckling curves.A numerical finite element model was developed to accurately predict the resistance of aluminum cross-sections. Its efficiency was validated by comparing its numerical predictions of resistance to available experimental test data. Extensive parametric studies were then conducted, allowing to study the impact of varying geometries, aluminium alloys and load cases on the resistance. Using the results from more than 2300 numerical simulations, O.I.C.-type design proposals were formulated for the local resistance of extruded and welded aluminum sections.The performance of the design equations was evaluated by comparing their resistance estimates to the reference numerical results and to resistance predictions from the Canadian, European, and American aluminum design standards. The comparisons showed that the O.I.C. design proposal leads to much more accurate and consistent results than these standards, while remaining simpler and more efficient.

Topology optimization of geothermal bore fields using the method of moving asymptotes

A new method is proposed to optimize the configurations of vertical ground heat exchangers using topology optimization and the method of moving asymptotes. The problem formulation minimizes the required number of boreholes of a given length with simultaneous constraints on the entering fluid temperature in cooling and heating mode. The method relies on the adaptation of the alternative ASHRAE design method and a new analytical formulation for the calculation of -functions based on a boundary condition of equal average fluid temperature. The method is applied to large bore fields consisting of more than a hundred boreholes. The paper also studies the effect of different types of domains and ground load profiles on the optimized configurations. It is shown that the shape of the domain has minimal impact on the optimized configurations. A higher density of boreholes on the perimeter of the domain compared to the center is recommended in the case where one operation mode is dominant. A uniform configuration is better suited when the load profile is balanced.

스마트도시사업 조성을 위한 중소도시 리빙랩 운영 사례

This study synthesized case studies of living labs in small and medium-sized cities among various types of projects that have been carried out by local governments as part of the Ministry of Land, Infrastructure and Transport's smart city development project. In particular, we derived a plan that can be used as a reference when promoting smart city development projects. Smart cities have been in the spotlight around the world as an alternative urban design method to solve urban problems and improve the quality of life of residents. Likewise, smart city development projects are becoming established in local governments through various public offering projects of central ministries. However, although it is recommended to have a bottom-up process of citizen participation in smart city creation, the weight of the discussion is different in each region, so a systematic discussion to standardize it was necessary. Therefore, solving social problems and social demands can no longer be considered only local issues, and this also applies to the creation of smart cities. In the end, in order to operate a smart city living lab sustainably and successfully, it is necessary to organize learning-evolving subject-specific communication activities along with online and offline-based feedback, which is left as a task for the next research.

Design of Aluminum Alloy H-Sections under Minor-Axis Bending

Much research has been reported on the global response of aluminum alloy H-sections members, while studies on the local buckling behavior of H-sections under pure bending remain relatively limited. The purpose of the research is to investigate the response of aluminum alloy H-sections subjected to minor axis bending. Using a finite element model, this study analyzed the stress distribution and failure mechanism of aluminum alloy H-sections under minor-axis bending and obtained the ultimate capacities of cross-sections covering a wide range of plate slenderness. The results were compared with the strength predictions based on EN1999-1-1 and the effective width method in AS/NZS 4600. The flange slenderness was found to play the most significant role in determining the normalized capacity. The sections are shown to exhibit an elastic-plastic stress distribution in the tensile flanges. The comparisons given in this study indicate that EN1999-1-1 underestimates the predicted bending strengths. The predictions based on the effective width method are shown to be more accurate than EN1999-1-1. An alternative design method is proposed for treating aluminum H-sections in minor axis bending. This method considers plastic stress distributions in the tensile flanges after the compressed flanges have locally buckled.

Effect of alternative load path design method on preventing progressive collapse and reducing the rehabilitation cost using FEMA-P58

The alternative load path (ALP) method is an important modern design approach to prevent progressive collapse of buildings by redesigning adjacent structural elements to provide an alternative load path in case of partial collapse. This may lead to tangible changes in the mass and stiffness of the building, which means a change in the seismic behavior of the building. This shows the fact that choosing and designing an alternative load path is not an easy task. Studying the improvement in the seismic behavior of the building, whether direct or indirect, as a result of using the ALP, is the main objective of this paper. To achieve this goal, this study examined approximately 96 models, including the study of the possibility of progressive collapse occurring, whether there is or isn't an alternative path for the loads using non-linear static and dynamic analysis, as well as evaluating the study models using various seismic evaluation methods, where both the nonlinear static pushover analysis method and the FEMA-P58 method were used and compared. The study models are divided into two sections, with and without (ALP). The study models are also categorized by building height using heights of 6, 9, 12 and 15 floors. The models were also divided based on the locations of weak points in the original design that may be susceptible to damage and lead to progressive collapse, whether they are internal, side, or corner weak columns. The findings from the examined models indicate that the efficiency of (ALP) systems is more prominent in low and mid-height buildings compared to tall buildings. Additionally, the results demonstrate that the FEMA-P58 method yields similar predictions regarding building behavior as traditional seismic assessment methods like pushover analysis, but in a simplified manner that benefits non-engineers by providing clear insights into the financial and temporal aspects of different structural system solutions.

Design of aluminum alloy channel sections bent about the minor axis

Aluminum alloy extruded channel sections are often used as rafters for light roofs, columns in framed buildings and chords of roof trusses. In this paper, a numerical study is carried out on the response of aluminum alloy channel sections under minor axis bending. Numerical models were developed and validated based on the experimental data of aluminum alloy channel sections under minor-axis bending. Subsequently, parametric studies covering various cross-sectional geometries were performed to expand the numerical data. The results were used to assess the applicability of Eurocode 9 slenderness limits, revealing that the Class 2 and Class 3 limits for outstand flanges under stress gradient with peak compression at tip are too conservative. Moreover, Eurocode 9 underestimates the predicted bending strengths of slender cross-sections due to the lack of consideration of the effect of stress gradient. The equivalent stress gradient factor applied in the effective thickness approach was proposed based on the buckling coefficient of BS 5950. For channel sections bent about minor-axis with the web in compression, flanges exhibit pronounced inelastic behavior even when the web locally buckles. An alternative design method based on the ultimate shape factor of a rectangular plate is proposed for semi-compact and slender channel sections in minor-axis bending (producing compression in the web), which leads to more favorable and less scattered capacity predictions.

Scalable level-wise screening experiments using locating arrays

Alternative design and analysis methods for screening experiments based on locating arrays are presented. The number of runs in a locating array grows logarithmically based on the number of factors, providing efficient methods for screening complex engineered systems, especially those with large numbers of categorical factors having different numbers of levels. Our analysis method focuses on levels of factors in the identification of important main effects and two-way interactions. We demonstrate the validity of our design and analysis methods on both well-studied and synthetic data sets and investigate both statistical and combinatorial properties of locating arrays that appear to be related to their screening capability.

Application of modified partial capacity design on six-story L-shaped reinforced concrete buildings with variations on elastic columns configurations

Modified Partial Capacity Design (M-PCD) is an alternative design method for seismic-resistant structures. M-PCD adopts the partial side sway mechanism for its failure mechanism where beams and some columns are allowed to develop plastic hinges. This method uses two models for design. The first model simulates a small earthquake occurrence and is used to design beams and plastic columns. The second model simulates a larger earthquake occurrence and damages on the structure. The elastic columns are designed based on the superposition of internal forces from the first and second models, provided that the effects from gravity loads are considered only once. This study focuses on the application of M-PCD on six-story L-shaped reinforced concrete buildings with variations on elastic columns configurations. Nonlinear time history analyses are used to determine the buildings’ performance on two earthquake levels (EDRS and MCER) and two earthquake directions (0° and 45° rotated earthquake). The results show that the partial side sway mechanism is observed in most of the analyzed structures and drifts are within set boundaries.

Architecture and the subconscious

The subconscious thinking governs the way the built environment is experienced and organised by its inhabitants. The collection of articles in this issue of ARSNET explores how our subconscious thinking provides alternative spatial narrative and design methods. The explorations in this issue highlight the different conditions and realms of the subconscious, as well as the various ways of learning and making driven by subjective subconsciousness. These inquiries offer deep thought on how the focus on subconscious thinking reveals hidden experiences and knowledge of architecture, as well as celebrating speculations and open-ended qualities that allow architecture to evolve.

A spatial model for biodiversity offsetting

In recent years, biodiversity offsetting has been adopted as a conservation strategy in many different countries. Biodiversity offsets are mechanisms used to compensate for ecological impacts resulting from development projects, especially those on non-built land uses. They usually rely on an equivalence principle based on achieving strict equality between the area that is developed and that which is offset. This approach still remains very controversial.This article explores an alternative offset design method, where we look at biodiversity from a functional perspective and conceive public policies that aim to conserve biodiversity by maintaining important structural features of the landscape, not limited to the proportion occupied by each land-use. We develop a spatially explicit land use change model to implement our geometric-based compensation method and we define three different versions of the public compensation policy. We apply the model to real case studies in two French municipalities and we compare the cost and feasibility of compensation under the different public policies. We find that offsetting is easier and cheaper when public policies aim to conserve no more than the targeted semi-natural land area, but this approach has major ecological limits. When considering more complex geometric properties of the landscape (and therefore higher ecological expectations), compensation becomes, on average, more difficult and more expensive. Our work shows how new approaches to ecological compensation could be defined and how models could help select the best options in the field.

Fire local stability of steel I-sections under simple load cases

The local buckling behavior of hot-rolled and welded I-sections under simple load cases at elevated temperatures is investigated numerically through extensive numerical analysis. Advanced shell Finite Element (F.E.) models are firstly developed and validated against existing experimental data for I-sections under fire conditions and then further used to carry out extensive parametric studies in order to consider a wide range of cross-section geometries, steel grades and temperatures. The reference F.E. results are subsequently compared with resistances predicted by the current European provisions. It is shown that these design provisions, which rely on similar cross-section classification and on the Effective Width Method (E.W.M.) just as room temperature rules, provide over-conservative and scattered resistance predictions to various extents. Therefore, an alternative design method – the Overall Interaction Concept (O.I·C.) – is proposed in this paper for I-sections at elevated temperatures. The O.I.C. is evidenced to provide more accurate, consistent and straightforward resistance predictions than current standards. Eventually, the reliability level of the O.I.C.-based proposals and of the current European provisions is evaluated.

Selection of Optimum Land Leveling Design Method for Surface Irrigation

Land leveling or land grading of surface irrigated fields improve irrigation water distribution and application efficiencies, conserve water and increases crop productivity. Land formation for irrigation face many constraints (ensuring proper slopes, prevention of flood, ensuring canal water command over the field, optimizing earthwork, minimizing truck travel distances, proper equipment utilization). Design engineers traditionally, perform site formation design manually by plane shape, least squire or linear programming methods. Such methods are with different characteristics. The main objective this study is to select and compare performance of these three design methods for proper land leveling design. Consequently, the basic theory of these alternative design methods are reviewed and their performance using data surveyed from five fields in Khartoum North-Sudan, each with different soil surface topographic configurations, is analyzed. The statistical analysis revealed that the linear programming method is the most appropriate design method. Employing the linear programming design method revealed that design slopes in row and cross row directions are within the acceptable range (0.1 to 0.5, the ratio of Cut/fill volumes is within the recommended range (1.1 to 1.3), uniformity of distribution of design elevations of grid points are acceptable and within the target limits (80%), while their deviation is at 80% of grid points around the mean before leveling.