Design Space Research Articles

Decomposition based estimation of distribution algorithm for high-level synthesis design space exploration

High-Level Synthesis (HLS) has evolved significantly due to the increasing complexity of integrated circuit design and the demand for efficient design methodologies. HLS, which raises the abstraction level of design specification, allows designers to focus on hardware functionality, thus enhancing productivity and reducing verification efforts. However, a key challenge in HLS is efficiently exploring the vast design space to find the Pareto-optimal designs. In this paper, we introduce a novel approach for multi-objective design space exploration in HLS. Our methodology decomposes the design space exploration problem into simpler sub-problems using the Multi-Objective Evolutionary Algorithm based on Decomposition (MOEA/D) framework and utilizes the Estimation of Distribution Algorithm (EDA) to build a probabilistic model for generating candidate solutions, thereby reducing the required number of expensive synthesis runs. Experimental results show that the proposed method has a faster convergence speed and reduces the number of syntheses by 24.34% to 32.01%, which significantly outperforms state-of-the-art works. Our approach achieves superior Pareto fronts with the lowest average ADRS value, outperforming Lattice-expl, ϵ -Constraint GA, and NSGA-II by 85.64%, 39.90%, and 33.31% respectively.

Home environments in an age of precarity

Environment-behavior research prior to the 2000s often portrayed homes as relatively self-contained, insular settings that provided residents refuge from the demands and distractions of the outside world—a kind of safe haven for domestic activities and family life. Residential security was viewed largely in relation to personal assets and the nearby environment, including one's capacity to afford high quality housing, defensible space design of the dwelling, and the absence of nearby threats such as fire and flood hazards, seismic risks, and undesirable land uses like oil drilling sites, landfills, and congested roadways. These proximal sources of residential precarity still play a role in people's lives, but their impacts on people are amplified nowadays by a variety of increasingly pervasive threats situated at societal and global levels such as climate change and extreme weather events, disease pandemics, rampant cybercrime, and growing worries about the spread of nuclear weapons. Also, the modern home has become a polyfunctional hub for both household and non-domestic activities, owing to the infusion of work, educational, and recreational activities into residences via their online connections to the outside world. We offer a social ecological analysis of the changing meanings and functions of home environments in the early 21st Century, and a conception of domestic precarity that highlights its links to broader existential concerns driven by societal and global forces. Future policies and environmental interventions to effectively curb residential precarity will require collaboration among individuals from multiple fields and between diverse organizations and institutions working at municipal, state, national and international levels.

Design optimization of phononic-fluidic resonator systems

Phononic-fluidic resonators utilize an acoustic fluid domain as a defect inside a solid metamaterial lattice, which can be used used to precisely measure acoustic properties of liquids. The design goal is to offer ideal boundary conditions for the acoustic resonator by matching defect resonance with phononic band gap. The design space of metamaterial or phononic crystal and fluidic resonator is nearly unlimited, especially when utilizing fully three-dimensional structures. In this work, we explore numerical shape and topology optimization to focus acoustic energy into the fluid domain and maximize the quality factor of the defect resonance. This requires the use of complex multi-frequency objective functions, while taking into account practical limits such as finite size and losses in the fluid and solid domains. Results highlight notable but limited improvements of quality factor with shape optimization starting from an initial design constrained by the maximum deformation possible. On the other hand, topology optimization results offer unique and unexpected ideas, and thus a deeper dive into the design space.

Comparative and optimal study of energy, exergy, and exergoeconomic performance in supercritical CO2 recompression combined cycles with organic rankine, trans-critical CO2, and kalina cycle

The bottom cycle in supercritical carbon dioxide (sCO2) recompression Brayton combined cycle (RCBC) effectively recovers substantial waste heat for electricity generation, enhancing energy utilization. The recovery efficiency is significantly influenced by the bottom cycle configurations and specific working conditions. Besides, implementing these bottom cycles introduces challenges related to increased system dimensions and design complexity. The present study aims to understand and evaluate the characteristics and optimal trade-offs of various bottom cycles, including trans-critical, subcritical, and non-azeotropic mixed working fluids, by establishing 3E (energy, exergy and Exergoeconomic) models for sCO2/tCO2, sCO2/ORC, and sCO2/KC combined cycle systems. To analysis and enhance interpretability, statistical Global Sensitivity Analysis (GSA) alongside unsupervised learning-based Self-Organizing Map (SOM) techniques and parametric analysis are employed. These methods identify key parameters and discern system patterns. Subsequently, the Non-Dominated Sorting Whale Optimization Algorithm (NSWOA) and entropy weight-based Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) are applied to establish a Pareto-optimal decision space and identify compromised ideal design points for each combined cycle. The results quantitatively rank sensitivity for objective variables within the design space in different combined cycles and visually represent system nonlinearity and coupling relationships in 2D weight planes using SOM. The TOPSIS trade-off points based on the Pareto frontier for the three combined cycles are ηth = 45.08 %, cp,tot = 8.5199 $/GJ, ηth = 45.13 %, cp,tot = 8.3739 $/GJ, and ηth = 48.97 %, cp,tot = 8.4783 $/GJ, respectively. Integrating machine learning techniques provides a comprehensive understanding of system patterns, offering valuable insights for decision-makers in the design and optimization of combined cogeneration cycles.

Comparison of emotional responses between young and elderly individuals under different sound source conditions

In the paper, four types of sound sources were selected, including animal sounds, human behavior sounds, natural sounds, and machine sounds. Each type of sound source contains eight types of sound sources. Six discrete emotions with anger, happiness, sadness, disgust, surprise, and fear are evaluated by young and elderly people through listening and questionnaire surveys under these sound source conditions. The results showed that machine sounds are more likely to cause emotions of anger and disgust, Natural sounds are more likely to trigger feelings of joy, sadness, surprise, or fear. Most of the six basic emotions are correlated with each other. In terms of the difference in evaluation between young and elderly people, most emotional response trends and degrees to various sound sources between young and elderly people are similar basically, but there are some sound sources that are obviously more likely to trigger related emotional reactions in young people, and less likely to trigger emotional reactions in elderly people. It provides a certain experimental reference basis for the sound environment design of urban public spaces.

Mass Optimization of a Multilayered Shield for Transportable Microreactors

The ability to easily transport microreactors is a major selling point for deploying microreactors to remote areas. However, this creates a unique shielding challenge, especially when the microreactor is being shipped after irradiation. A traditional reactor configuration utilizes a separate biological shield and pressure vessel to meet radiological shielding and pressure needs. The limited space available for transportable microreactors for both shielding and pressure vessels requires a revised assessment of separating out the biological shield and pressure vessel. To address these concerns, we examine a nuclear-grade sandwich composite (NGSC) that combines the reactor pressure vessel and biological shielding functions into a single component. Through a series of optimization problems for both transportation and operational use cases, the NGSC is able to minimize dose, minimize the vessel cost, and ensure that weight requirements are met for transportation. Initial results show that using a tungsten-tetraboride cermet in the first two layers of a six-layer NGSC provides adequate shielding for both use cases. These results show promise that an NGSC has enough overlap between operational and transportation cases to help reduce the design space for future analysis and assessment.

The impact of visitor attributes on the spatial experience in exhibition halls with background music

The exhibition hall is public architectural space with diverse forms, which serves as an exceptional research environment for investigating spatial experience. As a potent auditory stimulus capable of evoking emotions effectively, music exerts influence on behavioral responses in different contexts. However, the existing literature on interior space design rarely integrates soundscape considerations. Therefore, this study aims to explore the impact of tourist attributes-such as music learning experience, listening frequency, exhibition visiting motivation, personality traits, and neuroticism-on spatial experiences based on music perception and interior layouts. The background music is categorized into five sound conditions based on mode and tempo: no music, medium tempo in major, medium tempo in minor, fast tempo in major, and slow tempo in major. Meanwhile, the exhibition space is classified into four categories according to its interior layout: axis space, scale contrast space, shape contrast space, and flow space. The result shows that in different spatial environment with different music background, tourist attributes have different effects on the subjective spatial perception.

Development of a high-fidelity digital twin using the discrete element method for a continuous direct compression process. Part 2. Validation of calibration workflow

This paper is the second in a series of two that describes the application of discrete element method (DEM) and reduced order modeling to predict the effect of disturbances in the concentration of drug substance at the inlet of a continuous powder mixer on the concentration of the drug substance at the outlet of the mixer. In the companion publication, small-scale material characterization tests, a careful DEM parameter calibration and DEM simulations of the manufacturing process were used to develop a reliable RTD models. In the current work, the same calibration workflow was employed to evaluate the predictive ability of the resulting reduced-order model for an extended design space. DEM simulations were extrapolated using a relay race method and the cumulative RTD was accurately parameterized using the n-CSTR model. By performing experiments and simulations, a calibrated DEM model predicted the response of a continuous powder mixer to step changes in the inlet concentration of an API. Thus, carefully calibrated DEM models was used to guide and reduce experimental work and to establish an adequate control strategy. In addition, a further reduction in the computational effort was obtained by using the relay race method to extrapolate results. The predicted RTD curves were then parameterized to develop reduced order models and used to simulate the process in a matter of seconds. Overall, a control strategy evaluation tool based on high-fidelity DEM simulations was developed using material-sparing small-scale characterization tests.

Synthesis of a highly programmable multistable Kresling origami-inspired unit cell

Multistable origami structures have been exploited for mechanical property tailoring, deployable robotic arms, wave propagation tuning and others, due to its ability to possess multiple stable states with distinct properties. Traditionally these structures are made by assembling bistable unit cells, which results in a significant increase in the size and weight of the system when larger number of stable states are required. Recently, researchers have uncovered a third stable state in the Kresling origami pattern. Although this is an advancement over the bistable unit cell, there is an unexplored opportunity for more systematically expanding the design space of Kresling unit cells to possess many more stable configurations (>>2) and enhance its programmable multistability. In this research, we seek to develop a methodology for the design of a Kresling origami-inspired unit cell that can be easily programmed to achieve up to 10 stable configurations, with the potential to achieve even more. We exploit the rich kinematics of the Kresling origami-inspired unit cell, that arise from its coupled translational and rotational deployment, and propose the strategic integration of tensile elements to realize multiple stable states. Analytically, we study the unstretched length values (defined to be the precise length between the string “slacked” and “tensioned” configurations) of the strings that yield the distinct number of stable states. We present the potential energy profiles with its corresponding force-displacement plots for the bistable, tristable, quadstable, pentastable and decastable unit cells. Moreover, we show that by simply adjusting the unstretched length of the strings we can program and tune the number of stable states of the unit cell. Tristable and pentastable unit cell prototypes are designed and experimentally tested to validate the proposed methodology. Lastly, a study is performed on the mechanical property tailoring capabilities of two unit cells assembled in series. The results show that the decastable unit cell assembly can achieve up to 55 discrete values of equivalent stiffness, while the bistable one can only achieve 3. For the bistable unit cell assembly to match this number, it will require 54 unit cells in series, which will significantly increase the size and weight of the structural system. These findings show that the modular structure will have more programmable capabilities, while maintaining its size and weight at a minimum, as the number of stable states per unit cell is increased.

A-198 ESG Opportunities Harnessed During Pathology Transformation

Abstract Background Synnovis (a SYNLAB business) is in the process of delivering one of the largest Pathology transformation programmes in the UK, moving to a seven-site hub and spoke model from 89 laboratories over a dispersed geography. This remit also presented an opportunity for SYNLAB to deliver on its Environmental Social Governance (ESG) ambitions, by embedding ESG principles into programme delivery. There are several examples within each ESG pillar that demonstrate the benefits to be leveraged during transformation. Methods SYNLAB’s vision is to deliver sustainable diagnostic services. The integration of ESG into both the decision-making process and transformation structure ties these ambitions into programme benefits realisation. As well as setting performance level targets, the delivery of ESG benefits provide measures of success throughout the transformation journey, motivating stakeholders and building confidence along the way. Results Environment: The efficient use of space and LEAN principle design has consolidated the fragmented laboratory services spanning 15,000m2 into a bespoke, cutting-edge Pathology Hub with 6 spokes (hospital based services). The new hub building was designed to achieve BREEAM Excellent standards which measure performance against criteria such as energy management and efficiency, sustainable design and materials. The hub’s energy is from renewable-backed sources, and we will achieve a 47% reduction in CO2 equivalent (CO2e) emissions by unifying a significant proportion of its legacy footprint in this way. Further energy savings will be achieved through the associated analytical equipment consolidation, including a decrease from 50 to 14 microtomes, a decrease of 29 to 15 ventilated benches and a reduction of over 200 fridges and freezers across the service. In addition, substantial CO2e emissions savings are also being delivered by moving to a greener logistics provider, utilising electric vehicles and bikes. 2023 saw such emissions fall by 60% across Synnovis, helping to keep London’s air cleaner. Social: The transformation programme enables the hand back of over 6,000m2 of real estate to Synnovis’ NHS partners to use for critical hospital services (the equivalent of over 150 operating theatres). Governance Both internally and externally, ESG is integrated within the Synnovis organisational culture. For example, internally it applies mandatory sustainability metrics to its solution selection processes. These influenced the selection of Abbott’s Indexor solution to support the transformation of Blood Sciences, delivering a saving of over 2.8 million plastic sample bags every year. Externally, SYNLAB works with its partners to manage this substantial and complex transformation programme. Risk management is assured through transparency, securing confidence in the good use of public funds, ensuring responsiveness to customer and partner feedback, and ensuring accountability for and the delivery of targeted healthcare outcomes. Conclusions The integration of SYNLAB’s ESG strategy within the transformation programme is delivering tangible benefits across all ESG pillars. It has highlighted that in addition to the core outcome of services transformation, there are many more opportunities that can be realised as a result of making ESG an integral part of the pathology transformation programme.

New stability theory of model predictive control: modified stage cost approach

This paper presents a promising new approach to establish the stability of finite receding horizon control with a terminal cost. Departing from the traditional approaches of using the property of the terminal cost or relaxed Lyapunov inequalities, this paper establishes its stability based on the property of a modified stage cost. First, we rotate the stage cost with the terminal cost. Then a one-step optimisation problem is defined based on this augmented stage cost. It is shown that a slightly modified Model Predictive Control (MPC) algorithm is stable if the value function of the augmented one-step cost (OSVF) is a Control Lyapunov Function (CLF). Stability for MPC algorithms with zero terminal cost or even negative terminal cost can be unified with this new approach. Combining it with the existing MPC stability theories, we are able to significantly relax the stability requirement on MPC and extend the stabilising MPC design space to the region that no existing MPC stability theories can cover. The proposed stage cost-based approach will help to further reduce the gap between stability theory and practical applications of MPC and other optimisation-based control methods.

Precision Calibration in Wire-Arc-Directed Energy Deposition Simulations Using a Machine-Learning-Based Multi-Fidelity Model

Thermal simulation is essential in wire-arc-directed energy deposition (W-DED) to accurately estimate temperature distributions, impacting residual stress and distortion in components. Proper calibration of simulation models minimizes inaccuracies caused by varying material properties, machine settings, and environmental conditions. The lack of standardized calibration methods further complicates thermal predictions. This paper introduces a novel calibration method integrating both machine learning, as the high-fidelity (HF) model, and response surface modeling, as the low-fidelity (LF) model, within a multi-fidelity (MF) framework. The approach utilizes Bayesian optimization to effectively explore the search space for optimal solutions. A two-tiered model employs the LF model to identify feasible regions, followed by the HF model to refine calibration parameters, such as thermal efficiency (η), convection coefficient (h), and emissivity (ε), which are difficult to determine experimentally. A three-factor Box–Behnken design (BBD) is applied to explore the design space, requiring only thirteen parameter configurations, conserving resources and enabling robust model training. The efficacy of this MF model is demonstrated in multi-layer W-DED calibration, showing strong alignment between experimental and simulated temperatures, with a mean absolute error (MAE) of 7.47 °C. This method offers a replicable framework for broader additive manufacturing processes.

Design of Broadband Highly Efficient Power Amplifier Based on Low‐Pass Filtering Network With Periodic Structure

ABSTRACTIn this paper, a broadband high‐efficiency power amplifier (PA) is designed by using an easily implementable low‐pass filtering network with periodic structure as the output matching circuit to achieve bandwidth expansion of the PA. The proposed periodic structure is based on right‐handed T‐type basic cells, which can achieve wideband filtering responses. In addition, the load design space of the extended continuous Class‐F mode is combined as the target impedance to achieve an efficiency improvement in bandwidth PAs. For verification, a broadband highly efficient PA across 0.6–3.6 GHz with a relative bandwidth of 143% is designed, fabricated, and measured. The test results have shown a drain efficiency of 60.8%–70.4% and gain of 8.5–11.9 dB with a saturation output power under 3‐dB gain compression of 38.5–41.9 dBm.

Exploring the equitable inclusion of diverse voices in urban green design, planning and policy development: a scoping review protocol

IntroductionDespite the increasingly evidenced positive impacts of green space on human physical and mental health, green spaces remain inequitably distributed across different socioeconomic groups. Urban planning and design should prioritise...

Development of a Novel Beam-Based Finite-Element Approach for the Computationally Efficient Prediction of Residual Stresses and Displacements in Large 3D-Printed Polymer Parts

Recently, 3D printing of large, structural polymer parts has received increasing interest, especially for the creation of recyclable structural parts and tooling. However, the complexity of large-scale 3D polymeric printing often dictates resource-intensive trial and error processes to achieve acceptable parts. Existing computational models used to assess the impact of fabrication conditions typically treat the 3D-printed part as a continuum, incorporate oversimplified boundary conditions and take hours to days to run, making design space exploration infeasible. The purpose of this study is to create a structural model that is computationally efficient compared with traditional continuum models yet retains sufficient accuracy to enable exploration of the design space and prediction of part residual stresses and deformations. To this end, a beam-based finite element methodology was created where beads are represented as beams, vertical springs represent inter-bead transverse force transfer and multi-point, linear constraints enforce strain compatibility between adjacent beads. To test this framework, the fabrication of a large Polyethylene terephthalate glycol (PETG) wall was simulated. The PETG was modeled as linearly elastic with an experimentally derived temperature-dependent coefficient of thermal expansion and elastic modulus using temperature history imported from an ABAQUS thermal model. The results of the simulation were compared to those from a continuum model with an identical material definition, showing reasonable agreement of stresses and displacements. Further, the beam-based model required an order of magnitude less run time. Subsequently, the beam-based model was extended to allow separation of the part from the printing bed and the inclusion of part self-weight during fabrication to assess the significance of these effects that pose challenges for existing continuum models.

Integration of cognitive dynamics in the project to address the challenges of climate change.

Abstract This study addresses the pressing need for methodological innovation in response to climate change, with a particular focus on integrating cognitive dynamics with environmental design. The study is grounded in the theories of Extended Mind and Embodied Cognition, and proposes a novel approach that transcends traditional views. This approach uses innovation diagrams to analyse and integrate the physical and social environment as active elements of the cognitive process. The systemic approach is designed to develop practical tools and frameworks for the design of resilient and sustainable urban spaces that enhance human-environment interactions. The project not only seeks to provide new methodological insights but also fosters a holistic view that incorporates ecological sustainability in architectural and urban planning, thereby better addressing global environmental challenges.

Sex differences in physiological responses and thermal perception during repeated extremely cold exposure (−15 °C)

People working in cold regions often need to move frequently between indoor and outdoor environments. Due to sex differences in metabolic rates and thermal sensitivity, repeated exposure to large temperature differences may stress physiological and perceptual systems of males and females differently. This study aims to explore the physiological responses and thermal perception changes in males and females repeatedly exposed to −15 °C. The experiment involved 20 participants (gender balanced), who experienced two consecutive cycles of cold exposure. Each cycle included 30 min of cold exposure and 30 min of recovery. During the experiment, multiple physiological parameters as well as overall and local thermal perception were recorded. The experimental results indicate that repeated cold exposure can lead to thermal habituation in both males and females. Males exhibited higher skin temperatures in extremities such as the hands, fingers, face, and feet, while females reported lower thermal sensations in these areas during the recovery period. Furthermore, repeated cold exposure has a greater impact on the rate of recovery of extremity skin temperatures in females, requiring a longer recovery time compared to males. This article has reference value for considering sex differences in the design of temporary transition spaces in winter, which is beneficial to improving thermal comfort and energy efficiency.

Vegetation density is the main driver of insect species richness and diversity in small private urban front gardens

Urbanisation changes natural ecosystems and vegetation to urban green spaces, and causes insect communities to experience novel challenges for survival. New evidence suggests that urban green spaces, no matter how small, can provide meaningful habitats for insects. Information on design and management of small gardens (<6m2) in dense urban areas is still scarce. In particular, it is hardly known which garden designs provide most benefits to insects. We surveyed 65 small urban façade gardens (μ=1.7m2) in Amsterdam and The Hague in The Netherlands and measured various garden attributes that are expected to be relevant for general, flower-visiting and herbivorous insect species richness and diversity. Plant coverage and richness were the strongest predictors of insect biodiversity and species richness. We found no support for associations with native plants or garden size. Synthesis and applicationsTo strengthen insect biodiversity in the urban environment, we recommend future design of urban green spaces to focus on maximising coverage and richness of vegetation. Although there are advantages to using native species, we acknowledge that garden owners often prefer exotic species. Some of these can also affect insect diversity and abundances positively.

Regulatory and spectrum policy challenges for combined airspace and non-terrestrial networks

The recent advancements in the aviation and space industries facilitate new types of users in the sky, e.g., electrical vertical take-off and landing (eVTOL) aircraft. To unlock the full potential of these innovations, it is crucial to create interconnected three-dimensional networks that integrate airspace and non-terrestrial networks (NTNs) with their terrestrial counterparts, also known as Combined Airspace and Non-Terrestrial Networks (ASN). Combined ASN needs a flexible and adaptive network architecture with multiple, and partly converging technologies, such as air-to-ground, satellite, and high-altitude platforms, with a focus to cover both ground and aerial users. In addition to technical challenges, spectrum policy and regulatory aspects will affect the wireless network design and management schemes in three-dimensional space. Hence, this paper introduces regulatory and spectrum policy challenges posed by the development of combined ASN. This paper investigates a hypothetical urban air mobility use case with an eVTOL aircraft that operates as a flying taxi.

Evaluation of urban spaces in residential complexes Case study of Labdah neighborhood in Al-Khums

The urban space in urban centers is not only an element of beautifying the landscape in urban public centers, but it also carries multiple functional needs and shows cultural and social values. Based on the classification system of open space in urban centers, this study enhances the concept of urban space in urban centers, and analyzes the development pattern of its size and shape. The aim of the study is to evaluate the residential reality in the city of Al-Khums "Labdah neighborhood" specifically in terms of evaluating open spaces and their impact on social relations between individuals living in that neighborhood. The study highlights the problem of neglecting open space and its importance for the cultural and social needs among the population in the study area. This study included the concept of urban space, types of urban spaces in terms of closure, gradation and use, its characteristics, importance and impact on people. One of the most important results is highlighting the evaluation of urban spaces within residential complexes as a fundamental role in cultural exchange and social interaction between users of those spaces. The space must achieve cultural exchange, social cohesion and enhance equality between diversity, and aims to reach solutions that help meet the needs of residents in reconsidering the urban design of urban spaces within residential complexes. In addition to enhancing the culture of users of these spaces, preserving them and dealing with them in a civilized manner. Keywords: Urban space, Labdah district, open spaces, residential complexes.