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Search Results (1,986)

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Keywords = design space exploration

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24 pages, 8012 KiB  
Article
The Impact of Vegetation Layouts on Thermal Comfort in Urban Main Streets: A Case Study of Youth Street in Shenyang
by Lei Fan, Meiyue Zhao, Jiayi Huo, Yixuan Sha and Yan Zhou
Sustainability 2025, 17(4), 1755; https://doi.org/10.3390/su17041755 - 19 Feb 2025
Abstract
Urban streets are critical public spaces that significantly influence the thermal comfort of city dwellers. However, the issue of summer thermal discomfort in severely cold regions has been largely overlooked. This study focuses on Youth Street in Shenyang, a city in a severely [...] Read more.
Urban streets are critical public spaces that significantly influence the thermal comfort of city dwellers. However, the issue of summer thermal discomfort in severely cold regions has been largely overlooked. This study focuses on Youth Street in Shenyang, a city in a severely cold region, to explore the impact of various street spaces and vegetation layouts on the thermal environment and comfort using ENVI-met modeling and correlation analysis. The study varied the aspect ratio (AR) of the street, street tree species, and plant spacing across 60 scenarios and simulated thermal comfort over a 10-h period on a typical summer day. Results show that air temperature (Ta), mean radiant temperature (Tmrt) and sky view factor (SVF) are positively correlated with physiologically equivalent temperature (PET). Street trees effectively reduce Ta, increase RH and lower wind speed (WS), but plant spacing has minimal impact on WS. Higher AR values lead to greater improvements in pedestrian thermal comfort. Specifically, the highest heat mitigation rate (HMR) is observed at low AR (9.87% at AR = 0.5 and 9.94% at AR = 1.0), while it is lower at high AR (8.16% at AR = 2.0). Conversely, larger plant spacing of street trees diminishes the effectiveness of thermal comfort improvements. The improvement effect of plant spacing is more pronounced in street spaces with smaller AR. In these spaces, closer plant spacing significantly enhances thermal comfort by providing more shade and reducing Ta and Tmrt. However, in street spaces with higher AR, overly dense plant configurations can reduce WS and limit the cooling effect of ventilation, thereby diminishing overall heat mitigation ability. Conclusions suggest that urban planners should consider both street space and vegetation layouts to optimize thermal comfort. For urban main streets in severely cold regions, an AR of 1:1 with deciduous broadleaf trees and hedges planted at 6 m spacing is recommended. In high-AR streets, dense plant configurations should be avoided. This study provides valuable insights for improving the thermal comfort and sustainable design of urban street spaces, supporting new construction and development in similar climate environments. Full article
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Figure 1
<p>(<b>a</b>) Study area location; (<b>b</b>) site status photos and typical street planting forms; (<b>c</b>) the street elevation of the study area.</p>
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<p>(<b>a</b>) On Google Maps, the yellow line indicates Youth Street; (<b>b</b>) enlarged view of measuring streets, with the red dot indicating the measuring point; (<b>c</b>) fisheye lens image of measuring point.</p>
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<p>Example of a 3D street model.</p>
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<p>The trends and linear regression analysis of the simulated and measured values of Ta and RH at measuring points 4 and 5.</p>
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<p>The trends and linear regression analysis of the simulated and measured values of Ta and RH at measuring points 4 and 5.</p>
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<p>Scenario design.</p>
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<p>The measuring point SVF and PET from 09:00 to 18:00. (<b>a</b>) PET of current site with trees from 09:00 to 18:00. (<b>b</b>) PET of current site with no trees from 09:00 to 18:00.</p>
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<p>The variation of meteorological parameters at the site with and without trees.</p>
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<p>Ta of each scenario from 09:00 to 18:00.</p>
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<p>Ta of each scenario from 09:00 to 18:00.</p>
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<p>RH of each scenario from 09:00 to 18:00.</p>
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<p>RH of each scenario from 09:00 to 18:00.</p>
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<p>WS of each scenario from 09:00 to 18:00.</p>
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<p>WS of each scenario from 09:00 to 18:00.</p>
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<p>SVF of each scenario from 09:00 to 18:00.</p>
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<p>PET of each scenario from 09:00 to 18:00.</p>
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<p>PET of each scenario from 09:00 to 18:00.</p>
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<p>HMR of T5/6 m under different AR conditions.</p>
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26 pages, 8748 KiB  
Article
Behavioral Correlation-Based Residential Space Modularization Using Design Structure Matrix and Fuzzy C-Means Clustering Algorithm
by Fanbo Zeng, Xiaojun Rao, Jianhua Lei, Xujie Huo, Yuan Shi and Deng Ai
Buildings 2025, 15(4), 647; https://doi.org/10.3390/buildings15040647 - 19 Feb 2025
Abstract
This study introduces an automated method for constructing residential functional modules from the perspective of user behavior. By integrating the design structure matrix (DSM) and Fuzzy C-Means Clustering Algorithm (FCM), this approach systematically explores architectural functional modules. The DSM is employed to statistically [...] Read more.
This study introduces an automated method for constructing residential functional modules from the perspective of user behavior. By integrating the design structure matrix (DSM) and Fuzzy C-Means Clustering Algorithm (FCM), this approach systematically explores architectural functional modules. The DSM is employed to statistically analyze the correlations between residential behaviors. These correlations are then processed using FCM to generate various module segmentation schemes. The optimal scheme is selected based on modularity calculations. The results demonstrate improved modularity compared to traditional room-based designs, offering a greater variety of combinations and hierarchical organization. This methodology provides architects with a novel approach to address space integration challenges. Full article
(This article belongs to the Section Building Materials, and Repair & Renovation)
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<p>Functional room bubble diagram and corresponding plan.</p>
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<p>Generation of behavioral modularization.</p>
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<p>Illustration of a numerical DSM.</p>
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<p>DSM correlation matrices for physical, spatial, and temporal correlations.</p>
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<p>DSM correlation matrices for physical, spatial, and temporal correlations.</p>
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<p>DSM correlation matrices for comprehensive correlation.</p>
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<p>FCM algorithm program interface (created by the author).</p>
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<p>FCM algorithm program interface (created by the author).</p>
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<p>Behavioral module DSM for scheme R15. (Modules are represented by black boxes).</p>
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<p>Optimized behavioral module clustering scheme. (Black boxes: R14; red boxes: R8; blue boxes: R5).</p>
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<p>Hierarchical structure of residential space behavior module.</p>
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<p>Residential behavior space bubble diagram.</p>
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21 pages, 21560 KiB  
Article
Promoting Mental Health Through Campus Landscape Design: Insights from New Zealand Universities
by Yuqing He, Jacky Bowring and Gillian Lawson
Architecture 2025, 5(1), 16; https://doi.org/10.3390/architecture5010016 - 19 Feb 2025
Abstract
Mental health challenges among university students and staff are a pressing concern globally and in Aotearoa, New Zealand. Despite adopting frameworks like the Okanagan Charter to promote health and well-being, there is a lack of empirical research on how campus landscapes contribute to [...] Read more.
Mental health challenges among university students and staff are a pressing concern globally and in Aotearoa, New Zealand. Despite adopting frameworks like the Okanagan Charter to promote health and well-being, there is a lack of empirical research on how campus landscapes contribute to mental health promotion. This is a preliminary study based on a Ph.D. research project aiming to investigate the role of campus landscapes in supporting relaxation and internal recovery through everyday activities. We conducted a comparative multi-case study involving 66 participants from the University of Auckland, Lincoln University, and the University of Otago, exploring how they use and prefer campus landscapes for relaxation. Our findings indicate that ‘enjoying nature’ is the most preferred relaxation activity, with participants engaging both actively and passively with various spaces such as gardens, open lawns, and forested areas. Additionally, in campus settings, the proximity of relaxation spaces appears to be more important than design quality because of the limited time during working hours, which points to the importance of thoughtful campus planning. This study also found that university staff are often overlooked in discussions about healthy universities, despite their significant role in the campus setting. Overall, this study highlights the importance of biophilic design principles in creating health-promoting campus environments and offers initial insights for integrating natural elements into campus planning to enhance mental health and well-being. Full article
(This article belongs to the Special Issue Biophilic School Design for Health and Wellbeing)
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<p>The main geographical location of the selected campuses (own work, 2020).</p>
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<p>Participant LU15’s mental map shows trees on Lincoln University campus (from participant LU15, 2018).</p>
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<p>Participant LU6’s mental map shows lawn areas at Lincoln University (from participant LU6, 2018).</p>
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<p>Participant UO21 identified a flower-watching spot on her mental map of the University of Otago (from participant UO21, 2018).</p>
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<p>Campus users at the University of Otago enjoy natural features on the banks of the Leith River in more passive ways (photo by authors, 2018).</p>
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<p>Two people practised fencing on the banks of the Leith River at the University of Otago during a weekend (photo by authors, 2018).</p>
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<p>Campus users play volleyball on the Forbes Lawn at Lincoln University (photo by authors, 2018).</p>
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<p>The importance of the context of a space at Lincoln University (from participant LU12, 2018).</p>
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<p>The spatial character of the courtyard of the School of Architecture and Planning, University of Auckland (from participant UA17, 2018).</p>
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<p>The location of the little forest at Lincoln University (modified from Google Map, 2020).</p>
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<p>The view inside the little forest at Lincoln University (photo by authors, 2018).</p>
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<p>A fully paved campus street at the University of Otago (photo by authors, 2018).</p>
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<p>The main activity centres at (from top to bottom) (<b>a</b>) Lincoln University, (<b>b</b>) the University of Auckland, and (<b>c</b>) the University of Otago (photos by authors, 2020).</p>
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<p>The secret garden at Lincoln University blocked by the adjacent building block (photo by authors, 2019).</p>
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<p>Albert Park as one get-away space for campus users at the University of Auckland (photo by authors, 2018).</p>
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26 pages, 5315 KiB  
Article
Biomimicry-Based Design of Underground Cold Storage Facilities: Energy Efficiency and Sustainability
by Mugdha Kshirsagar, Sanjay Kulkarni, Ankush Kumar Meena, Danby Caetano D’costa, Aroushi Bhagwat, Md Irfanul Haque Siddiqui and Dan Dobrotă
Biomimetics 2025, 10(2), 122; https://doi.org/10.3390/biomimetics10020122 - 18 Feb 2025
Viewed by 168
Abstract
Underground cold storage gives rise to special challenges that require innovative solutions to ensure maximum energy efficiency. Conventional energy systems tend to be based on high energy use, so sustainable solutions are crucial. This study explores the novel idea of biomimetics and how [...] Read more.
Underground cold storage gives rise to special challenges that require innovative solutions to ensure maximum energy efficiency. Conventional energy systems tend to be based on high energy use, so sustainable solutions are crucial. This study explores the novel idea of biomimetics and how it might be used in the planning and building of underground cold storage facilities as well as other infrastructure projects. Biomimetic strategies, inspired by termite mounds, gentoo penguin feathers, and beehive structures, are applied to minimize reliance on energy-intensive cooling systems. These natural models offer efficient thermal regulation, airflow optimization, and passive cooling mechanisms such as geothermal energy harvesting. The integration of naturally driven convection and ventilation ensures stable internal temperatures under varying conditions. Biomimicry was employed in Revit Architecture, coupled with structural optimization, to eliminate urban space’s limitations and further increase energy efficiency. The analytical work for this paper utilized a set of formulas that represent heat flow, thermal resistance, R-value, thermal transmittance, U-value, solar absorption, and G-value. The results pointed to very good insulation, with exterior walls having an R-value of 10.2 m2K/W and U-value of 0.98 W/m2K. Among the chosen 3-layer ETFE cushion with a U-value of 1.96 W/m2K, with a G-value of 0.50, showed good heat regulation and daylight management. Furthermore, bagasse-cement composites with a very low thermal conductivity of 0.10–0.30 W/m·K provided good insulation. This research proposes a scalable and sustainable approach in the design of underground cold storage by merging modelling based on Revit with thermal simulations. Biomimicry has been demonstrated to have the potential for changing subterranean infrastructure, conserving energy consumption, and creating eco-friendly construction practices. Full article
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<p>Methodology Flowchart.</p>
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<p>Dimensions of the proposed storage boxes.</p>
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<p>Iceberg concept implemented for the cold storage facility with (90:10) underground-to-above-ground ratio (made using Revit).</p>
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<p>ETFE roofing in a research building in Braunschweig, Germany. Source: <a href="https://specialtyfabricsreview.com/wp-content/uploads/sites/28/2018/03/6907_20171222_1N4V9587_1_Hanno-Keppel.jpg" target="_blank">https://specialtyfabricsreview.com/wp-content/uploads/sites/28/2018/03/6907_20171222_1N4V9587_1_Hanno-Keppel.jpg</a> (accessed on 1 December 2024). Photos: Hanno Keppel.</p>
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<p>3-layer ETFE cushion system implemented in the surface warehouse facility (made using Revit).</p>
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<p>Body structure of a Gentoo penguin.</p>
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<p>Cross-section of the exterior wall of subsurface cold storage facility showing the layers of insulation.</p>
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<p>Induced flow model for termite mound ventilation.</p>
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<p>Schematic Drawing of ventilator hoods.</p>
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<p>Structure A: Bagasse-Cement Composite Wall.</p>
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<p>Structure B: Common insulating wall.</p>
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<p>Structure C: Regular masonry wall.</p>
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<p>Spread of forces on a hexagon cell.</p>
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<p>Difference between regular and non-regular tessellating patterns.</p>
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14 pages, 2101 KiB  
Article
Policy-Based Reinforcement Learning Approach in Imperfect Information Card Game
by Kamil Chrustowski and Piotr Duch
Appl. Sci. 2025, 15(4), 2121; https://doi.org/10.3390/app15042121 - 17 Feb 2025
Viewed by 233
Abstract
Games provide an excellent testing ground for machine learning and artificial intelligence, offering diverse environments with strategic challenges and complex decision-making scenarios. This study seeks to design a self-learning artificial intelligent agent capable of playing the trick-taking stage of the popular card game [...] Read more.
Games provide an excellent testing ground for machine learning and artificial intelligence, offering diverse environments with strategic challenges and complex decision-making scenarios. This study seeks to design a self-learning artificial intelligent agent capable of playing the trick-taking stage of the popular card game Thousand, known for its complex bidding system and dynamic gameplay. Due to the game’s vast state space and strategic complexity, other artificial intelligence approaches, such as Monte Carlo Tree Search and Deep Counterfactual Regret Minimisation, are infeasible. To address these challenges, the enhanced version of the REINFORCE policy gradient algorithm is proposed. Introducing a score-related parameter β designed to guide the learning process by prioritising valuable games, the proposed approach enhances policy updates and improves overall learning outcomes. Moreover, leveraging the off-policy experience replay, along with the importance weighting of behavioural policy, enhanced training stability and reduced model variance. The proposed algorithm was applied to the trick-taking stage of the popular game Thousand Schnapsen in a two-player setup. Four distinct neural network models were explored to evaluate the performance of the proposed approach. A custom test suite of selected deals and tournament evaluations was employed to assess effectiveness. Comparisons were made against two benchmark strategies: a random strategy agent and an alpha-beta pruning tree search with varying search depths. The proposed algorithm achieved win rates exceeding 65% against the random agent, nearly 60% against alpha-beta pruning at a search depth of 6, and 55% against alpha-beta pruning at the maximum possible depth. Full article
(This article belongs to the Special Issue Advancements and Applications in Reinforcement Learning)
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Figure 1
<p>Each plot presents a learning curve during pretraining of an agent equipped with different MLP. The parameters of NNs were, apart from the size of hidden layers and composition, the same: <math display="inline"><semantics> <mrow> <mi>b</mi> <mi>a</mi> <mi>t</mi> <mi>c</mi> <mi>h</mi> <mi>s</mi> <mi>i</mi> <mi>z</mi> <mi>e</mi> <mo>=</mo> <mn>64</mn> </mrow> </semantics></math>, <math display="inline"><semantics> <mrow> <mi>α</mi> <mo>=</mo> <msup> <mn>10</mn> <mrow> <mo>−</mo> <mn>3</mn> </mrow> </msup> </mrow> </semantics></math>, <math display="inline"><semantics> <mrow> <mi>e</mi> <mi>p</mi> <mi>i</mi> <mi>s</mi> <mi>o</mi> <mi>d</mi> <mi>e</mi> <mi>s</mi> <mo>=</mo> <mn>7</mn> <mo>×</mo> <msup> <mn>10</mn> <mn>6</mn> </msup> </mrow> </semantics></math>. The plots outline the first 60,000 training episodes to notice some slight differences between suggested models of NNs.</p>
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<p>The plots report a learning curve (averaged count of invalid actions per episode) of playing in the trick-taking environment by interaction. One can notice the advantage of the single NN over the cluster of nine NNs. Reducing the <math display="inline"><semantics> <mi>α</mi> </semantics></math> value can improve the learning of the policy. The best solution is presented in (<b>a</b>). (<b>a</b>) Single NN, <math display="inline"><semantics> <mrow> <mi>k</mi> <mo>=</mo> <mn>16</mn> </mrow> </semantics></math>, <math display="inline"><semantics> <mrow> <mi>α</mi> <mo>=</mo> <msup> <mn>10</mn> <mrow> <mo>−</mo> <mn>6</mn> </mrow> </msup> </mrow> </semantics></math>, <math display="inline"><semantics> <mrow> <mi>e</mi> <mi>p</mi> <mi>i</mi> <mi>s</mi> <mi>o</mi> <mi>d</mi> <mi>e</mi> <mi>s</mi> <mo>=</mo> <msup> <mn>10</mn> <mn>5</mn> </msup> </mrow> </semantics></math>, <math display="inline"><semantics> <mrow> <mi>b</mi> <mi>a</mi> <mi>t</mi> <mi>c</mi> <mi>h</mi> <mi>s</mi> <mi>i</mi> <mi>z</mi> <mi>e</mi> <mo>=</mo> <mn>128</mn> </mrow> </semantics></math>. (<b>b</b>) Single NN, <math display="inline"><semantics> <mrow> <mi>k</mi> <mo>=</mo> <mn>16</mn> </mrow> </semantics></math>, <math display="inline"><semantics> <mrow> <mi>α</mi> <mo>=</mo> <msup> <mn>10</mn> <mrow> <mo>−</mo> <mn>5</mn> </mrow> </msup> </mrow> </semantics></math>, <math display="inline"><semantics> <mrow> <mi>e</mi> <mi>p</mi> <mi>i</mi> <mi>s</mi> <mi>o</mi> <mi>d</mi> <mi>e</mi> <mi>s</mi> <mo>=</mo> <msup> <mn>10</mn> <mn>5</mn> </msup> </mrow> </semantics></math>, <math display="inline"><semantics> <mrow> <mi>b</mi> <mi>a</mi> <mi>t</mi> <mi>c</mi> <mi>h</mi> <mi>s</mi> <mi>i</mi> <mi>z</mi> <mi>e</mi> <mo>=</mo> <mn>128</mn> </mrow> </semantics></math>. (<b>c</b>) Cluster of NNs, <math display="inline"><semantics> <mrow> <mi>k</mi> <mo>=</mo> <mn>16</mn> </mrow> </semantics></math>, <math display="inline"><semantics> <mrow> <mi>α</mi> <mo>=</mo> <msup> <mn>10</mn> <mrow> <mo>−</mo> <mn>6</mn> </mrow> </msup> </mrow> </semantics></math>, <math display="inline"><semantics> <mrow> <mi>e</mi> <mi>p</mi> <mi>i</mi> <mi>s</mi> <mi>o</mi> <mi>d</mi> <mi>e</mi> <mi>s</mi> <mo>=</mo> <msup> <mn>10</mn> <mn>5</mn> </msup> </mrow> </semantics></math>, <math display="inline"><semantics> <mrow> <mi>b</mi> <mi>a</mi> <mi>t</mi> <mi>c</mi> <mi>h</mi> <mi>s</mi> <mi>i</mi> <mi>z</mi> <mi>e</mi> <mo>=</mo> <mn>128</mn> </mrow> </semantics></math>. (<b>d</b>) Cluster of NNs, <math display="inline"><semantics> <mrow> <mi>k</mi> <mo>=</mo> <mn>16</mn> </mrow> </semantics></math>, <math display="inline"><semantics> <mrow> <mi>α</mi> <mo>=</mo> <msup> <mn>10</mn> <mrow> <mo>−</mo> <mn>5</mn> </mrow> </msup> </mrow> </semantics></math>, <math display="inline"><semantics> <mrow> <mi>e</mi> <mi>p</mi> <mi>i</mi> <mi>s</mi> <mi>o</mi> <mi>d</mi> <mi>e</mi> <mi>s</mi> <mo>=</mo> <msup> <mn>10</mn> <mn>5</mn> </msup> </mrow> </semantics></math>, <math display="inline"><semantics> <mrow> <mi>b</mi> <mi>a</mi> <mi>t</mi> <mi>c</mi> <mi>h</mi> <mi>s</mi> <mi>i</mi> <mi>z</mi> <mi>e</mi> <mo>=</mo> <mn>128</mn> </mrow> </semantics></math>.</p>
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<p>The plots highlight learning progress following the pure RL approach without pretraining. The results indicated that pretraining significantly improves the speed of convergence. (<b>a</b>) Cluster of NNs, <math display="inline"><semantics> <mrow> <mi>k</mi> <mo>=</mo> <mn>16</mn> </mrow> </semantics></math>, <math display="inline"><semantics> <mrow> <mi>α</mi> <mo>=</mo> <msup> <mn>10</mn> <mrow> <mo>−</mo> <mn>6</mn> </mrow> </msup> </mrow> </semantics></math>, <math display="inline"><semantics> <mrow> <mi>e</mi> <mi>p</mi> <mi>i</mi> <mi>s</mi> <mi>o</mi> <mi>d</mi> <mi>e</mi> <mi>s</mi> <mo>=</mo> <msup> <mn>10</mn> <mn>5</mn> </msup> </mrow> </semantics></math>, <math display="inline"><semantics> <mrow> <mi>b</mi> <mi>a</mi> <mi>t</mi> <mi>c</mi> <mi>h</mi> <mi>s</mi> <mi>i</mi> <mi>z</mi> <mi>e</mi> <mo>=</mo> <mn>128</mn> </mrow> </semantics></math>. (<b>b</b>) Single NN, <math display="inline"><semantics> <mrow> <mi>k</mi> <mo>=</mo> <mn>16</mn> </mrow> </semantics></math>, <math display="inline"><semantics> <mrow> <mi>α</mi> <mo>=</mo> <msup> <mn>10</mn> <mrow> <mo>−</mo> <mn>5</mn> </mrow> </msup> </mrow> </semantics></math>, <math display="inline"><semantics> <mrow> <mi>e</mi> <mi>p</mi> <mi>i</mi> <mi>s</mi> <mi>o</mi> <mi>d</mi> <mi>e</mi> <mi>s</mi> <mo>=</mo> <msup> <mn>10</mn> <mn>5</mn> </msup> </mrow> </semantics></math>, <math display="inline"><semantics> <mrow> <mi>b</mi> <mi>a</mi> <mi>t</mi> <mi>c</mi> <mi>h</mi> <mi>s</mi> <mi>i</mi> <mi>z</mi> <mi>e</mi> <mo>=</mo> <mn>128</mn> </mrow> </semantics></math>.</p>
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<p>Plots show the score achieved by each player during the evaluation epoch. The assessed agent had the single-large NN <math display="inline"><semantics> <mrow> <mo>(</mo> <mi>k</mi> <mo>=</mo> <mn>16</mn> <mo>)</mo> </mrow> </semantics></math> as a function approximator. The learning hyperparameters for that setting were <math display="inline"><semantics> <mrow> <mi>b</mi> <mi>a</mi> <mi>t</mi> <mi>c</mi> <mi>h</mi> <mi>s</mi> <mi>i</mi> <mi>z</mi> <mi>e</mi> <mo>=</mo> <mn>128</mn> </mrow> </semantics></math>, <math display="inline"><semantics> <mrow> <mi>α</mi> <mo>=</mo> <msup> <mn>10</mn> <mrow> <mo>−</mo> <mn>6</mn> </mrow> </msup> </mrow> </semantics></math>, <math display="inline"><semantics> <mrow> <mi>e</mi> <mi>p</mi> <mi>i</mi> <mi>s</mi> <mi>o</mi> <mi>d</mi> <mi>e</mi> <mi>s</mi> <mo>=</mo> <msup> <mn>10</mn> <mn>6</mn> </msup> </mrow> </semantics></math>.</p>
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20 pages, 2610 KiB  
Article
DynGraph-BERT: Combining BERT and GNN Using Dynamic Graphs for Inductive Semi-Supervised Text Classification
by Eliton Luiz Scardin Perin, Mariana Caravanti de Souza, Jonathan de Andrade Silva and Edson Takashi Matsubara
Informatics 2025, 12(1), 20; https://doi.org/10.3390/informatics12010020 - 17 Feb 2025
Viewed by 122
Abstract
The combination of Bidirecional Encoder Representations from Transformers (BERT) and Graph Neural Networks (GNNs) has been extensively explored in the text classification literature, usually employing BERT as a feature extractor combined with heterogeneous static graphs. BERT transfers information via token embeddings, which are [...] Read more.
The combination of Bidirecional Encoder Representations from Transformers (BERT) and Graph Neural Networks (GNNs) has been extensively explored in the text classification literature, usually employing BERT as a feature extractor combined with heterogeneous static graphs. BERT transfers information via token embeddings, which are propagated through GNNs. Text-specific information defines a static heterogeneous graph. Static graphs represent specific relationships and do not have the flexibility to add new knowledge to the graph. To address this issue, we build a tied connection between BERT and GNN exclusively using token embeddings to define the graph and propagate the embeddings, which can force the BERT to redefine the GNN graph topology to improve accuracy. Thus, in this study, we re-examine the design spaces and test the limits of what this pure homogeneous graph using BERT embeddings can achieve. Homogeneous graphs offer structural simplicity and greater generalization capabilities, particularly when integrated with robust representations like those provided by BERT. To improve accuracy, the proposed approach also incorporates text augmentation and label propagation at test time. Experimental results show that the proposed method outperforms state-of-the-art methods across all datasets analyzed, with consistent accuracy improvements as more labeled examples are included. Full article
(This article belongs to the Section Machine Learning)
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<p>Overview of the DynGraph-BERT training process for a single epoch.</p>
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<p>Illustration of the dynamic graph generation for each batch during training and testing. The nodes and cylinders colors indicate the link between them. Best view in color.</p>
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<p>Overview of the DynGraph-BERT training process across epochs. Colors in the graph represent node identification.</p>
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<p>Testing procedure of DynGraph-BERT: label propagation at test time.</p>
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<p>Accuracy results for training data increments.</p>
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<p>Plots for ablation study. (<b>a</b>) Maximum number of neighbors for graph construction on the Snippets dataset. (<b>b</b>) Minimum similarity for graph construction on the Snippets dataset. (<b>c</b>) Variation of <math display="inline"><semantics> <mi>λ</mi> </semantics></math> in the model’s loss function for the Ohsumed and AGNews datasets.</p>
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31 pages, 12588 KiB  
Article
Evaluating Spatial Attributes of Surface Colors Under Daylight and Electrical Lighting in Sustainable Architecture
by Carolina Espinoza-Sanhueza, Marc Hébert, Jean-François Lalonde and Claude Demers
Sustainability 2025, 17(4), 1653; https://doi.org/10.3390/su17041653 - 17 Feb 2025
Viewed by 185
Abstract
This paper investigates the spatial attributes of the color properties and brightness characteristics of sustainable architectural strategies including daylight, electrical lighting, and surface color in architecture, which could potentially impact users’ spatial experiences. Images of 48 spaces varying in surface color configurations, type [...] Read more.
This paper investigates the spatial attributes of the color properties and brightness characteristics of sustainable architectural strategies including daylight, electrical lighting, and surface color in architecture, which could potentially impact users’ spatial experiences. Images of 48 spaces varying in surface color configurations, type of light source, and position of the lighting strategy were evaluated. The analyses included assessments of color palettes, descriptors based on saturation and brightness properties, and brightness distribution maps. The results indicate that lighting design and types of light source influence the saturation and brightness properties of the perceived hues evaluated in the same environment, leading to variations in color descriptors or adjectives. Furthermore, this study demonstrates that variations in brightness between bright and dark zones, the creation of focal points, and perceived spatial fragmentation depend on the reflectance of the colors applied in the surfaces, the position of the lighting, and the type of light source. This study does not aim to establish best practices for enhancing users’ emotions through architecture. Instead, it explores how variations in color and light influence perceptual descriptions that have been previously associated with emotional responses. This research recognizes the impact of sustainable strategies including surface colors under daylight and electrical lighting on users’ spatial experiences. Full article
(This article belongs to the Section Health, Well-Being and Sustainability)
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<p>Comparison of surface color applications and type of sky. Colors are altered according to floor color surface. Percentages and brightness distributions in grayscale maps [<a href="#B33-sustainability-17-01653" class="html-bibr">33</a>] are altered according to each surface color configuration and type of light source.</p>
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<p>The experimental setup used in the research based on previous studies; it was previously employed in the research by Espinoza-Sanhueza et al. [<a href="#B56-sustainability-17-01653" class="html-bibr">56</a>]. The number circles correspond to (1) exo-structure, (2) plywood shell, (3) interior panels, (4) ceiling with different lighting strategy, (5) the support of the electrical system, and (a′) camera installation from the point of view of the observer.</p>
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<p>A graphical display of the surface color configuration concepts tested under three different lighting strategies. The selection of floor color in the complementary cases (5) and (6) and triads (7) and (8) are based on the reflectance percentages established by Brown and DeKay [<a href="#B71-sustainability-17-01653" class="html-bibr">71</a>].</p>
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<p>The installation of the LED light strips for scenarios under electrical lighting.</p>
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<p>The aspect of an HDR image and the tone-mapping operators used to illustrate color, saturation, and brightness on images.</p>
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<p>Image treatment and workflow analyses.</p>
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<p>A graphical collection of color samples according to the lighting strategy. The numbers correspond to the color samples in a color palette with 5 tones.</p>
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<p>Two-dimensional graphic color descriptors related to human emotions (in red) based on saturation and brightness properties. Color descriptors were retrieved from the research of Valdez and Mehrabian [<a href="#B47-sustainability-17-01653" class="html-bibr">47</a>], Divers, [<a href="#B48-sustainability-17-01653" class="html-bibr">48</a>] Dael et al., [<a href="#B50-sustainability-17-01653" class="html-bibr">50</a>] Al-Ayash et al., [<a href="#B51-sustainability-17-01653" class="html-bibr">51</a>] Wilms and Oberfeld, [<a href="#B52-sustainability-17-01653" class="html-bibr">52</a>] Gao and Xin [<a href="#B53-sustainability-17-01653" class="html-bibr">53</a>] and Gao et al., [<a href="#B54-sustainability-17-01653" class="html-bibr">54</a>] Béguin, [<a href="#B90-sustainability-17-01653" class="html-bibr">90</a>] Le Grand [<a href="#B91-sustainability-17-01653" class="html-bibr">91</a>], Adeline [<a href="#B92-sustainability-17-01653" class="html-bibr">92</a>], Pracontal [<a href="#B93-sustainability-17-01653" class="html-bibr">93</a>], and Bergeon et al. [<a href="#B94-sustainability-17-01653" class="html-bibr">94</a>] and applied in studies by Bülow-Hübe [<a href="#B95-sustainability-17-01653" class="html-bibr">95</a>], Russell and Pratt [<a href="#B43-sustainability-17-01653" class="html-bibr">43</a>], Poirier et al. [<a href="#B22-sustainability-17-01653" class="html-bibr">22</a>], Arsenault et al. [<a href="#B96-sustainability-17-01653" class="html-bibr">96</a>], and Pineault and Dubois [<a href="#B97-sustainability-17-01653" class="html-bibr">97</a>].</p>
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<p>An overview of the 48 scenarios under daylight and electrical lighting.</p>
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<p>Differences in chromatic contrast between daylight and electrical lighting in the (6) Complementary 2 scene. Contemporary Orange-Blue FL 5500 K retrieved from the research of Espinoza-Sanhueza et al. [<a href="#B56-sustainability-17-01653" class="html-bibr">56</a>].</p>
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<p>Effects of the luminaire position in the color palettes generated for the (7) Primary Triad and (8) Secondary Triad scenes. Spaces retrieved from Espinoza-Sanhueza et al. [<a href="#B56-sustainability-17-01653" class="html-bibr">56</a>].</p>
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<p>A graphical display of the color palette (top) and HSB color descriptors of the Triad-Primary scenes under SL, FL, and ZL electrical lighting at 5500 K. The analysis is based on saturation and brightness properties retrieved from Bülow-Hübe [<a href="#B95-sustainability-17-01653" class="html-bibr">95</a>], Küller [<a href="#B102-sustainability-17-01653" class="html-bibr">102</a>], Russell and Pratt [<a href="#B43-sustainability-17-01653" class="html-bibr">43</a>], Poirier, Demers and Potvin, Arsenault, Hébert and Dubois [<a href="#B96-sustainability-17-01653" class="html-bibr">96</a>] Pineault and Dubois [<a href="#B97-sustainability-17-01653" class="html-bibr">97</a>] and Chen et al. [<a href="#B49-sustainability-17-01653" class="html-bibr">49</a>] and supported by the PAD theory [<a href="#B47-sustainability-17-01653" class="html-bibr">47</a>] and Value (brightness)–Chroma (saturation) paradigm [<a href="#B47-sustainability-17-01653" class="html-bibr">47</a>].</p>
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<p>A graphical display of color palette (top) and HSB color descriptors of the Triad-Secondary scenes under SL, FL, and ZL electrical lighting at 5500 K. The analysis is based on saturation and brightness properties retrieved from Bülow-Hübe [<a href="#B95-sustainability-17-01653" class="html-bibr">95</a>], Küller [<a href="#B102-sustainability-17-01653" class="html-bibr">102</a>], Russell and Pratt [<a href="#B43-sustainability-17-01653" class="html-bibr">43</a>], Poirier, Demers and Potvin [<a href="#B22-sustainability-17-01653" class="html-bibr">22</a>], Arsenault, Hébert and Dubois [<a href="#B96-sustainability-17-01653" class="html-bibr">96</a>], Pineault and Dubois [<a href="#B97-sustainability-17-01653" class="html-bibr">97</a>], and Chen et al. [<a href="#B49-sustainability-17-01653" class="html-bibr">49</a>] and supported by the PAD theory [<a href="#B47-sustainability-17-01653" class="html-bibr">47</a>] and Value (brightness)—Chroma (saturation) paradigm [<a href="#B48-sustainability-17-01653" class="html-bibr">48</a>].</p>
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<p>Luminous effects and brightness distribution maps according to lighting position and type of light source. Effect classification inspired by Demers [<a href="#B34-sustainability-17-01653" class="html-bibr">34</a>,<a href="#B63-sustainability-17-01653" class="html-bibr">63</a>].</p>
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<p>An interpretation of the light and color attributes in an architectural space using the presented methodology.</p>
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<p>The benchmarking of the environments under daylight.</p>
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<p>Brightness distribution map of environments under daylight.</p>
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<p>The benchmarking of the environments with electrical lighting at 5500 K. The images were used in previous studies by Espinoza-Sanhueza et al. [<a href="#B56-sustainability-17-01653" class="html-bibr">56</a>].</p>
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<p>Brightness distribution maps with electrical lighting at 5500 K. Posterized images retrieved from the research of Espinoza-Sanhueza et al. [<a href="#B56-sustainability-17-01653" class="html-bibr">56</a>].</p>
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19 pages, 11085 KiB  
Article
Understanding Urban Park-Based Social Interaction in Shanghai During the COVID-19 Pandemic: Insights from Large-Scale Social Media Analysis
by Haotian Wang, Tianyu Su and Wanting Zhao
ISPRS Int. J. Geo-Inf. 2025, 14(2), 87; https://doi.org/10.3390/ijgi14020087 - 17 Feb 2025
Viewed by 194
Abstract
The COVID-19 pandemic highlighted the role of urban parks as green spaces in mitigating social isolation and supporting public mental health. Research in this area is limited due to the lack of large-scale datasets. Moreover, timely studies are indeed necessary under pandemic conditions. [...] Read more.
The COVID-19 pandemic highlighted the role of urban parks as green spaces in mitigating social isolation and supporting public mental health. Research in this area is limited due to the lack of large-scale datasets. Moreover, timely studies are indeed necessary under pandemic conditions. This study employs quantitative methods to analyze the temporal and spatial changes in social interaction in 160 urban parks before, during, and after the COVID-19 pandemic, and assesses their correlation with the built environment. Social media data from the Dianping platform were collected for this purpose. A two-step analytical approach was employed: first, machine learning-based keyword analysis identified review data related to social interaction, leading to the construction of two indicators: social interaction intensity and social interaction recovery rate. Second, we applied regression models to explore the correlation between the two indicators in urban parks and 18 characteristics of the built environment. The built environment characteristics associated with social interaction intensity varied across different periods, with seven factors, including natural landscapes, perceptual experience, building density, and road intersections, showing significant correlations with the recovery of social interaction capabilities in the post-pandemic era. Based on these findings, it is recommended that urban planners consider integrating more flexible design element, such as adding greenery and enriching the audio-visual experience for visitors. Furthermore, enhancing the quality and accessibility of park amenities can foster social interaction, thereby contributing to public health resilience in future crises. This research recommends that urban park design should not only support communities’ immediate needs but also prepare for unforeseen challenges. Full article
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<p>Spatial distribution of study and other parks in Shanghai.</p>
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<p>Methodology framework.</p>
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<p>Word frequency of reviews in Shanghai during pre- (<b>a</b>), mid- (<b>b</b>), and post- (<b>c</b>) the period of the first wave of COVID-19.</p>
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<p>Spatial distribution map of local regression coefficients for variables significantly correlated with parks’ social interaction recovery rates.</p>
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26 pages, 2233 KiB  
Article
Exploring the Impact of Local Operator Configurations in the Multi-Demand Multidimensional Knapsack Problem
by José García, Ivo Cattarinich, Paola Moraga and Hernan Pinto
Appl. Sci. 2025, 15(4), 2059; https://doi.org/10.3390/app15042059 - 16 Feb 2025
Viewed by 161
Abstract
The Multi-demand Multidimensional Knapsack Problem (MDMKP) is a challenging combinatorial task due to its capacity and demand constraints. Local search operators play a key role in metaheuristics when navigating such complex solution spaces, yet their impact on MDMKP performance has received limited attention. [...] Read more.
The Multi-demand Multidimensional Knapsack Problem (MDMKP) is a challenging combinatorial task due to its capacity and demand constraints. Local search operators play a key role in metaheuristics when navigating such complex solution spaces, yet their impact on MDMKP performance has received limited attention. In this work, we investigate four local operator configurations—Add, Drop, Swap, and All Operator—within the Whale Optimization Algorithm framework. Our approach integrates these operators to broaden search coverage and refine candidate solutions. This design aims to enhance solution quality by balancing exploration and exploitation across multiple dimensions of the MDMKP. Experimental results on benchmark instances with different sizes (n=100,250, and 500) show that the All Operator configuration consistently achieves better maximum and average values. In large-scale instances (n = 500), the “All Operator” configuration achieves an average maximum value of 107,967, which is approximately 1.4% higher than the 106,490 achieved by the “Add Operator” and about 0.2% higher than the 107,771 obtained by the “Swap Operator”, while significantly outperforming the “Drop Operator” (average maximum of 99,164). Statistical tests confirm its advantage over the other configurations, suggesting that combining multiple local operators can significantly strengthen performance in high-dimensional and constraint-heavy settings like the MDMKP. Full article
(This article belongs to the Special Issue Novel Research and Applications on Optimization Algorithms)
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<p>The Developed Swarm Intelligence-Based Machine Learning Algorithm.</p>
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<p>Violin plots (<b>top row</b>) show the distribution of %GAP values for averages and maximums across configurations. Scatter plots (<b>bottom row</b>) compare %GAP values relative to the best-known solution for averages (<b>left</b>) and maximums (<b>right</b>) for small-sized instances (<math display="inline"><semantics> <mrow> <mi>n</mi> <mo>=</mo> <mn>100</mn> </mrow> </semantics></math>).</p>
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<p>Comparison of %GAP across different operators for average and maximum values relative to the best-known solution. The left panel shows the scatter plots of %GAP for averages, while the right panel displays %GAP for maximums. The violin and scatter plots below illustrate the distribution of %GAP for averages and maximums, emphasizing the variability and performance of each operator.</p>
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<p>Comparison of %GAP across different operators for <span class="html-italic">n</span> = 500 when evaluating average and maximum values relative to the best-known solution. The left panel presents scatter plots of %GAP for average results, and the right panel shows %GAP for maximum outcomes. Below these, the violin and scatter plots illustrate the distribution of %GAP, emphasizing the performance and variability among the operators.</p>
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<p>Sensitivity analysis results for the parameter <span class="html-italic">L</span>. (<b>a</b>) %GAP of maximum value. (<b>b</b>) %GAP of average maximum value.</p>
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18 pages, 5310 KiB  
Article
A Hybrid Neural Architecture Search Algorithm Optimized via Lifespan Particle Swarm Optimization for Coal Mine Image Recognition
by Jian Cheng, Jinbo Jiang, Haidong Kang and Lianbo Ma
Mathematics 2025, 13(4), 631; https://doi.org/10.3390/math13040631 - 14 Feb 2025
Viewed by 266
Abstract
Coal mine scene image recognition plays an important role in safety monitoring and equipment detection. However, traditional methods often depend on manually designed neural network architectures. These models struggle to handle the complex backgrounds, low illumination, and diverse objects commonly found in coal [...] Read more.
Coal mine scene image recognition plays an important role in safety monitoring and equipment detection. However, traditional methods often depend on manually designed neural network architectures. These models struggle to handle the complex backgrounds, low illumination, and diverse objects commonly found in coal mine environments. Manual designs are not only inefficient but also restrict the exploration of optimal architectures, resulting to subpar performance. To address these challenges, we propose using a neural architecture search (NAS) to automate the design of neural networks. Traditional NAS methods are known to be computationally expensive. To improve this, we enhance the process by incorporating Particle Swarm Optimization (PSO), a scalable algorithm that effectively balances global and local searches. To further enhance PSO’s efficiency, we integrate the lifespan mechanism, which prevents premature convergence and enables a more comprehensive exploration of the search space. Our proposed method establishes a flexible search space that includes various types of convolutional layers, activation functions, pooling operations, and network depths, enabling a comprehensive optimization process. Extensive experiments show that the Lifespan-PSO NAS method outperforms traditional manually designed networks and standard PSO-based NAS approaches, offering significant improvements in both recognition accuracy (improved by 10%) and computational efficiency (resource usage reduced by 30%). This makes it a highly effective solution for real-world coal mine image recognition tasks via a PSO-optimized approach in terms of performance and efficiency. Full article
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<p>An example of coal mine scene recognition. It can be seen that in scenes with severe noise and dust, the effectiveness of the object detection model will be greatly reduced, with an average decrease of 0.02 in accuracy, which is catastrophic.</p>
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<p>This figure shows the evolution process of an architecture, which involves continuously selecting high-precision architecture units to choose the optimal architecture and iterating until the optimal architecture is found.</p>
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<p>The recognition platform. Users input images and use our method to improve the effectiveness of object detection, which still performs well under high noise conditions.</p>
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<p>The framework of MBConv. The MBConv structure works as follows: Expansion: a 1 × 1 convolution is used to increase the number of channels. Depthwise convolution: a depthwise convolution is applied, followed by a 1 × 1 pointwise convolution to combine channels. Linear bottleneck: the output passes through a linear layer (without activation), followed by a skip connection if the number of channels matches the input.</p>
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<p>A comparison of the results between YOLOv5s (<b>left</b>) and our (<b>right</b>) method. Our method achieves a detection confidence score of 0.84 for the positive sample “helmet” (right image). This represents a 6.3% increase compared to the confidence score of the left image, indicating a significant improvement in the reliability of target recognition.</p>
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<p>A comparison of the results between YOLOv5s (<b>left</b>) and our (<b>right</b>) method shows that, even with variations in target positions, our method also achieves a detection confidence score of 0.68 and 0.81 for the positive sample “helmet”, which is 15.3% and 8% higher than that of the left image; the improved method significantly enhances helmet detection effectiveness.</p>
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<p>Training results: classification loss and DFL loss. After training, the DFL loss and classification loss decreased to a relatively low level and showed convergence, indicating that the training effect was good.</p>
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<p>Training results: IoU loss and total loss. Both total loss and IoU loss showed convergence and reached a relatively low level. IoU loss reached about 0.12, and total loss reached about 1.41.</p>
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<p>Validation results: classification loss and DFL loss. As shown in the figure, the validation loss also remains at a low level and gradually decreases until convergence occurs. Val class loss reached about 0.16, and DFL loss reached about 0.63.</p>
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<p>Validation results: IoU loss and total loss. To be specific, IoU loss and total loss also remain at a low level and gradually decrease until convergence occurs. IoU loss reached about 0.20, and total loss reached about 1.45.</p>
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<p>Results: Precision@0.50 and Recall@0.50. After multiple epochs of training, the accuracy and recall reached a fairly good level. The target dataset consists of three categories: helmet, head, and person.</p>
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<p>Results: F1@0.50 and Map@0.50. The F1@0.50 value reached about 0.62, and the mAP@0.50 value reached about 0.95, proving that the overall training effect is significant.</p>
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40 pages, 3140 KiB  
Review
Enhancing CubeSat Communication Through Beam-Steering Antennas: A Review of Technologies and Challenges
by Tale Saeidi and Saeid Karamzadeh
Electronics 2025, 14(4), 754; https://doi.org/10.3390/electronics14040754 - 14 Feb 2025
Viewed by 471
Abstract
With their compact design and versatility, CubeSats have emerged as critical platforms for advancing space exploration and communication technologies. However, achieving reliable and efficient communication in the dynamic and constrained environment of low Earth orbit (LEO) remains a significant challenge. Beam-steering antenna systems [...] Read more.
With their compact design and versatility, CubeSats have emerged as critical platforms for advancing space exploration and communication technologies. However, achieving reliable and efficient communication in the dynamic and constrained environment of low Earth orbit (LEO) remains a significant challenge. Beam-steering antenna systems offer a promising solution to address these limitations, enabling adaptive communication links with improved gain and coverage. This review article provides a comprehensive analysis of the state-of-the-art in CubeSat communication, concentrating on the latest developments in beam-steering antennas. By synthesizing the findings from recent studies, the key challenges are highlighted, including power constraints, miniaturization, and integration with CubeSat platforms. Furthermore, this paper investigates cutting-edge techniques, such as phased array systems, metasurface-based designs, and reconfigurable antennas, which pave the way for enhanced performance. This study can serve as a resource for researchers and engineers, offering insights into current trends and future opportunities for advancing CubeSat communications through innovative antenna systems. Full article
(This article belongs to the Special Issue Antenna Designs for 5G/IoT and Space Applications, 2nd Edition)
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<p>CubeSat communications.</p>
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<p>CubeSat designs: (<b>left</b>) 1U; (<b>middle</b>) 2U; (<b>right</b>) 3U [<a href="#B1-electronics-14-00754" class="html-bibr">1</a>].</p>
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<p>A metal-only wideband patch antenna designed for a CubeSat [<a href="#B19-electronics-14-00754" class="html-bibr">19</a>].</p>
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<p>S-band antenna serving as the ground for an X-band array in a dual-frequency S-/X-band design [<a href="#B40-electronics-14-00754" class="html-bibr">40</a>].</p>
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<p>Design and fabrication of a crescent-shaped microstrip patch antenna with an annular ring structure for X-band applications and compact integration [<a href="#B41-electronics-14-00754" class="html-bibr">41</a>].</p>
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<p>Beam steering with different feeds.</p>
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<p>The design of metasurface antennas.</p>
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<p>The design of a reconfigurable antenna.</p>
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24 pages, 3804 KiB  
Review
A Review of Artificial Intelligence Applications in Architectural Design: Energy-Saving Renovations and Adaptive Building Envelopes
by Yangluxi Li, Huishu Chen, Peijun Yu and Li Yang
Energies 2025, 18(4), 918; https://doi.org/10.3390/en18040918 - 14 Feb 2025
Viewed by 303
Abstract
This paper explores the applications and impacts of artificial intelligence (AI) in building envelopes and interior space design. The relevant literature was searched using databases such as Science Direct, Web of Science, Scopus, and CNKI, and 89 studies were selected for analysis based [...] Read more.
This paper explores the applications and impacts of artificial intelligence (AI) in building envelopes and interior space design. The relevant literature was searched using databases such as Science Direct, Web of Science, Scopus, and CNKI, and 89 studies were selected for analysis based on the PRISMA protocol. This paper first analyzes the role of AI in transforming architectural design methods, particularly its different roles in the auxiliary, collaborative, and leading design processes. It then discusses AI’s applications in the energy-efficient renovation of building envelopes, smart façade design for cold climate buildings, and thermal imaging detection. Furthermore, this paper summarizes AI-based interior space environment design methods, covering the current state of research, applications, impacts, and challenges both domestically and internationally. Finally, this paper looks ahead to the broad prospects for AI technology in the architecture and interior design fields while addressing the challenges related to the integration of personalized design and environmental sustainability concepts. Full article
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<p>Computer-aided design process.</p>
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<p>Case-based reasoning aided design process.</p>
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<p>The research framework of this paper.</p>
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<p>Meta-analysis.</p>
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<p>Some key nodes of the intelligent evolution of the building skin [<a href="#B35-energies-18-00918" class="html-bibr">35</a>].</p>
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<p>History of the development of building energy efficiency standards in China [<a href="#B35-energies-18-00918" class="html-bibr">35</a>]).</p>
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<p>Thermal, visual, and olfactory sub-environments and their influencing factors [<a href="#B61-energies-18-00918" class="html-bibr">61</a>].</p>
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17 pages, 4982 KiB  
Article
ZPTM: Zigzag Path Tracking Method for Agricultural Vehicles Using Point Cloud Representation
by Shuang Yang, Engen Zhang, Yufei Liu, Juan Du and Xiang Yin
Sensors 2025, 25(4), 1110; https://doi.org/10.3390/s25041110 - 12 Feb 2025
Viewed by 327
Abstract
Automatic navigation, as one of the modern technologies in farming automation, enables unmanned driving and operation of agricultural vehicles. In this research, the ZPTM (Zigzag Path Tracking Method) was proposed to reduce the complexity of path planning by using a point cloud consisting [...] Read more.
Automatic navigation, as one of the modern technologies in farming automation, enables unmanned driving and operation of agricultural vehicles. In this research, the ZPTM (Zigzag Path Tracking Method) was proposed to reduce the complexity of path planning by using a point cloud consisting of a series of anchor points with spatial information, which are obtained from orthophotos taken by UAVs (Unmanned Aerial Vehicles) to represent the curved path in the zigzag. A local straight path was created by linking two adjacent anchor points, forming the local target path to be tracked, which simplified the navigation algorithm for zigzag path tracking. A nonlinear feedback function was established, using both lateral and heading errors as inputs for determining the desired heading angle of agricultural vehicles, which were guided along the local target path with minimal errors. A GUI (Graphic User Interface) was designed on the navigation terminal to visualize and monitor the working process of agricultural vehicles in automatic navigation, displaying interactive controls and components, including representations of the zigzag path and the agricultural vehicle using affine transformation. A high-clearance sprayer equipped with an automatic navigation system was utilized as the test platform to evaluate the proposed ZPTM. Zigzag navigation tests were conducted to explore the impact of path tracking parameters, including path curvature, moving speed, and spacing between anchor points, on zigzag navigation performance. Based on these tests, a regression model was established to optimize these parameters for achieving accurate and smooth movement. Field test results showed that the maximum error, average error, and RMS (Root Mean Square) error in the zigzag navigation were 3.30 cm, 2.04 cm, and 2.27 cm, respectively. These results indicate that the point cloud path-based ZPTM in this research demonstrates adequate stability, accuracy, and applicability in zigzag navigation. Full article
(This article belongs to the Section Sensors and Robotics)
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<p>Components of test platform.</p>
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<p>The process of (<b>a</b>) image acquisition by DJI Phantom 4 and (<b>b</b>) zigzag path planning.</p>
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<p>Flow chart of DPA.</p>
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<p>An example of the DPA: (<b>a</b>) Original point-cloud path. (<b>b</b>–<b>d</b>) Process using DPA. (<b>e</b>) Result after applying DPA. (<b>f</b>) Comparison of original and simplified point-cloud path.</p>
Full article ">Figure 5
<p>Point cloud path tracking algorithm: <math display="inline"><semantics> <mrow> <msubsup> <mrow> <mi>ω</mi> </mrow> <mrow> <mi>c</mi> <mo>−</mo> <mn>1</mn> </mrow> <mrow> <mo>∗</mo> </mrow> </msubsup> <mo>,</mo> <mo> </mo> <msubsup> <mrow> <mi>ω</mi> </mrow> <mrow> <mi>c</mi> </mrow> <mrow> <mo>∗</mo> </mrow> </msubsup> <mo>,</mo> <mo> </mo> <msubsup> <mrow> <mi>ω</mi> </mrow> <mrow> <mi>c</mi> <mo>+</mo> <mn>1</mn> </mrow> <mrow> <mo>∗</mo> </mrow> </msubsup> <mo>,</mo> <mo> </mo> <msubsup> <mrow> <mi>ω</mi> </mrow> <mrow> <mi>k</mi> </mrow> <mrow> <mo>∗</mo> </mrow> </msubsup> </mrow> </semantics></math> and <math display="inline"><semantics> <mrow> <msubsup> <mrow> <mi>ω</mi> </mrow> <mrow> <mi>k</mi> <mo>+</mo> <mn>1</mn> </mrow> <mrow> <mo>∗</mo> </mrow> </msubsup> </mrow> </semantics></math> are anchor points in the point cloud path. C is the movement center of the agricultural vehicle chassis, representing the vehicle position. <span class="html-italic">η</span> is the nearest point from the vehicle position to the point cloud path. <span class="html-italic">Q</span> is the target point. <span class="html-italic">θ<sub>0</sub></span> is the heading angle of the agricultural vehicle. <span class="html-italic">θ</span> is the desired heading angle of the agricultural vehicle. <span class="html-italic">∆θ</span> is the heading error defined as the angle between vector <math display="inline"><semantics> <mrow> <mover accent="true"> <mrow> <mi>C</mi> <mi>Q</mi> </mrow> <mo>→</mo> </mover> </mrow> </semantics></math> and the heading of the vehicle. <span class="html-italic">e<sub>y</sub></span> is the lateral error defined as the perpendicular distance from C to vector <math display="inline"><semantics> <mrow> <mover accent="true"> <mrow> <msubsup> <mrow> <mi>ω</mi> </mrow> <mrow> <mi>c</mi> </mrow> <mrow> <mo>∗</mo> </mrow> </msubsup> <msubsup> <mrow> <mi>ω</mi> </mrow> <mrow> <mi>c</mi> <mo>+</mo> <mn>1</mn> </mrow> <mrow> <mo>∗</mo> </mrow> </msubsup> </mrow> <mo>→</mo> </mover> </mrow> </semantics></math>.</p>
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<p>The GUI.</p>
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<p>Coordinate transformation: Left-O-Up is the screen coordinate system. P<sub>1</sub> and P<sub>2</sub> are adjacent anchor points in the UTM coordinate system that form the local target path. P<sub>m</sub> is the midpoint of the local target path. <span class="html-italic">τ</span> is the angle between the local target path and the UTM northing. P′<sub>1</sub> and P′<sub>2</sub> are the anchor points after rotation of P<sub>1</sub> and P<sub>2</sub>, respectively. P<sub>scr1</sub> and P<sub>scr2</sub> are anchor points for converting the local target path to the screen. The screen resolution is <span class="html-italic">W<sub>scr</sub></span> × <span class="html-italic">H<sub>scr</sub></span>.</p>
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<p>Zigzag navigation tests with (<b>a</b>) the high-clearance sprayer in (<b>b</b>) different zigzag path curvatures for the same turn.</p>
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<p>The actual trajectories of the high-clearance sprayer following five target zigzag paths.</p>
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<p>Comparative analysis of RMS in response to changes in (<b>a</b>) curvature, (<b>b</b>) speed, and (<b>c</b>) spacing.</p>
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<p>The test scene.</p>
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<p>Actual trajectories and enlarged images of the high-clearance sprayer following the entry and exit paths.</p>
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29 pages, 4553 KiB  
Article
Simultaneous Source Number Detection and DOA Estimation Using Deep Neural Network and K2-Means Clustering with Prior Knowledge
by Aifei Liu, Yuan Zhou, Zi Li, Yuxuan Xie, Cao Zeng and Zhiling Liu
Electronics 2025, 14(4), 713; https://doi.org/10.3390/electronics14040713 - 12 Feb 2025
Viewed by 312
Abstract
Source number detection and Direction-of-Arrival (DOA) estimation are usually addressed in two stages, leading to high computational load. This paper proposes a simple solution to efficiently estimate the source number and DOAs using deep neural network (DNN) and clustering, named DNN-C. By observing [...] Read more.
Source number detection and Direction-of-Arrival (DOA) estimation are usually addressed in two stages, leading to high computational load. This paper proposes a simple solution to efficiently estimate the source number and DOAs using deep neural network (DNN) and clustering, named DNN-C. By observing that sources in space are usually few, DNN-C uses a simple fully connected DNN to obtain a spatial spectrum. Then, the K2-means clustering is specially designed to extract the source information from the obtained spatial spectrum. In particular, to enable the proposed DNN-C with the ability to detect the mixed sources, we first develop a new strategy for training data generation, and provide a guideline for data balance setting. We then explore the prior knowledge of array signal processing and spatial spectrum to obtain a peak vector and propose to add a virtual peak into the peak vector, and thus transform the task of source detection as a binary clustering problem of noise and sources. Overall, DNN-C provides a lightweight solution to implement source number detection and DOA estimation simultaneously and efficiently. Its testing time is about 2 times less than the classical solution (i.e., minimum descriptive length and multiple signal classification, shortened as MDL-MUSIC) when the grid step is 1° Importantly, it is robust to nonuniform noise by nature and can identify the absence of sources. The effectiveness of DNN-C is verified by simulation results. Furthermore, the DNN-C model trained by simulated data shows its generalization to real data measured by a circular array of eight sensors. Full article
(This article belongs to the Section Circuit and Signal Processing)
Show Figures

Figure 1

Figure 1
<p>Array signal model for a uniform linear array: <math display="inline"><semantics> <mrow> <msub> <mi>s</mi> <mi>k</mi> </msub> <mrow> <mo>(</mo> <mi>t</mi> <mo>)</mo> </mrow> </mrow> </semantics></math> and <math display="inline"><semantics> <msub> <mi>θ</mi> <mi>k</mi> </msub> </semantics></math> are the waveform and DOA of the <span class="html-italic">k</span>-th sources, respectively; <span class="html-italic">d</span> is the distance between two adjacent sensors; the steering vector at <math display="inline"><semantics> <msub> <mi>θ</mi> <mi>k</mi> </msub> </semantics></math> is <math display="inline"><semantics> <mrow> <mi mathvariant="bold">a</mi> <mrow> <mo>(</mo> <msub> <mi>θ</mi> <mi>k</mi> </msub> <mo>)</mo> </mrow> <mo>=</mo> <mrow> <mo>[</mo> <mn>1</mn> <mspace width="1.em"/> <msup> <mi>e</mi> <mrow> <mi>j</mi> <mn>2</mn> <mi>π</mi> <mi>d</mi> <mi>s</mi> <mi>i</mi> <mi>n</mi> <msub> <mi>θ</mi> <mi>k</mi> </msub> <mo>/</mo> <mi>λ</mi> </mrow> </msup> <mo>⋯</mo> <msup> <mi>e</mi> <mrow> <mi>j</mi> <mn>2</mn> <mi>π</mi> <mrow> <mo>(</mo> <mi>M</mi> <mo>−</mo> <mn>1</mn> <mo>)</mo> </mrow> <mi>d</mi> <mi>s</mi> <mi>i</mi> <mi>n</mi> <msub> <mi>θ</mi> <mi>k</mi> </msub> <mo>/</mo> <mi>λ</mi> </mrow> </msup> <mo>]</mo> </mrow> </mrow> </semantics></math>; the received signal at the <span class="html-italic">m</span>-th sensor is <math display="inline"><semantics> <mrow> <msub> <mi>r</mi> <mi>m</mi> </msub> <mrow> <mo>(</mo> <mi>t</mi> <mo>)</mo> </mrow> </mrow> </semantics></math>; and the received array signal vector is <math display="inline"><semantics> <mrow> <mi mathvariant="bold">r</mi> <mrow> <mo>(</mo> <mi>t</mi> <mo>)</mo> </mrow> <mo>=</mo> <msup> <mrow> <mo>[</mo> <msub> <mi>r</mi> <mn>1</mn> </msub> <mrow> <mo>(</mo> <mi>t</mi> <mo>)</mo> </mrow> <mo>,</mo> <msub> <mi>r</mi> <mn>2</mn> </msub> <mrow> <mo>(</mo> <mi>t</mi> <mo>)</mo> </mrow> <mo>,</mo> <mo>⋯</mo> <msub> <mi>r</mi> <mi>M</mi> </msub> <mrow> <mo>(</mo> <mi>t</mi> <mo>)</mo> </mrow> <mo>]</mo> </mrow> <mi>T</mi> </msup> </mrow> </semantics></math>.</p>
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<p>Scheme of DNN-C.</p>
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<p>Structure of DNN; for the autoencoder, we define the size of each of the input and output layers as <math display="inline"><semantics> <mrow> <mover accent="true"> <mi>J</mi> <mo>˜</mo> </mover> <mo>=</mo> <mi>M</mi> <mrow> <mo>(</mo> <mi>M</mi> <mo>−</mo> <mn>1</mn> <mo>)</mo> </mrow> </mrow> </semantics></math> since the input vector <math display="inline"><semantics> <mi mathvariant="bold">x</mi> </semantics></math> has a size of <math display="inline"><semantics> <mrow> <mi>M</mi> <mo>(</mo> <mi>M</mi> <mo>−</mo> <mn>1</mn> <mo>)</mo> </mrow> </semantics></math>. In addition, we denote that the number of each encoder and decoder has one hidden layer of which the size is <math display="inline"><semantics> <mrow> <mo>⌊</mo> <mstyle scriptlevel="0" displaystyle="true"> <mfrac> <mover accent="true"> <mi>J</mi> <mo>˜</mo> </mover> <mn>2</mn> </mfrac> </mstyle> <mo>⌋</mo> </mrow> </semantics></math>, and denote the number of spatial subregions as <span class="html-italic">p</span>. For each of the multi-layer classifiers after the autoencoder, the sizes of the two hidden layers are, respectively, <math display="inline"><semantics> <mrow> <mo>⌊</mo> <mstyle scriptlevel="0" displaystyle="true"> <mfrac> <mn>2</mn> <mn>3</mn> </mfrac> </mstyle> <mover accent="true"> <mi>J</mi> <mo>˜</mo> </mover> <mo>⌋</mo> </mrow> </semantics></math> and <math display="inline"><semantics> <mrow> <mo>⌊</mo> <mstyle scriptlevel="0" displaystyle="true"> <mfrac> <mn>4</mn> <mn>9</mn> </mfrac> </mstyle> <mover accent="true"> <mi>J</mi> <mo>˜</mo> </mover> <mo>⌋</mo> </mrow> </semantics></math>.</p>
Full article ">Figure 4
<p>Spatial spectrum of DNN for real data with a source of <math display="inline"><semantics> <mrow> <msub> <mi>θ</mi> <mn>1</mn> </msub> <mo>=</mo> <mn>8</mn> <mo>°</mo> </mrow> </semantics></math> and an estimated SNR of 50 dB. The red cross corresponds to the true DOA of source (i.e., 8°).</p>
Full article ">Figure 5
<p>Spatial spectra of DNN-C under different virtual peaks in absence of sources; (<b>a</b>) <math display="inline"><semantics> <mrow> <msub> <mi>p</mi> <mrow> <mi>v</mi> <mi>i</mi> <mi>r</mi> </mrow> </msub> <mo>=</mo> <mn>0.1</mn> </mrow> </semantics></math>; (<b>b</b>) <math display="inline"><semantics> <mrow> <msub> <mi>p</mi> <mrow> <mi>v</mi> <mi>i</mi> <mi>r</mi> </mrow> </msub> <mo>=</mo> <mn>0.2</mn> </mrow> </semantics></math>; (<b>c</b>) <math display="inline"><semantics> <mrow> <msub> <mi>p</mi> <mrow> <mi>v</mi> <mi>i</mi> <mi>r</mi> </mrow> </msub> <mo>=</mo> <mn>0.3</mn> </mrow> </semantics></math>; (<b>d</b>) <math display="inline"><semantics> <mrow> <msub> <mi>p</mi> <mrow> <mi>v</mi> <mi>i</mi> <mi>r</mi> </mrow> </msub> <mo>=</mo> <mn>0.4</mn> </mrow> </semantics></math>.</p>
Full article ">Figure 6
<p>Spatial spectra of DNN-C under different virtual peaks in presence of two sources with DOAs of <math display="inline"><semantics> <mrow> <mo>(</mo> <msub> <mi>θ</mi> <mn>1</mn> </msub> <mo>=</mo> <mo>−</mo> <mn>40.1</mn> <mo>°</mo> <mo>,</mo> <msub> <mi>θ</mi> <mn>2</mn> </msub> <mo>=</mo> <mo>−</mo> <mn>28.2</mn> <mo>°</mo> <mo>)</mo> </mrow> </semantics></math>; (<b>a</b>) <math display="inline"><semantics> <mrow> <msub> <mi>p</mi> <mrow> <mi>v</mi> <mi>i</mi> <mi>r</mi> </mrow> </msub> <mo>=</mo> <mn>0.3</mn> </mrow> </semantics></math>; (<b>b</b>) <math display="inline"><semantics> <mrow> <msub> <mi>p</mi> <mrow> <mi>v</mi> <mi>i</mi> <mi>r</mi> </mrow> </msub> <mo>=</mo> <mn>0.4</mn> </mrow> </semantics></math>; (<b>c</b>) <math display="inline"><semantics> <mrow> <msub> <mi>p</mi> <mrow> <mi>v</mi> <mi>i</mi> <mi>r</mi> </mrow> </msub> <mo>=</mo> <mn>0.5</mn> </mrow> </semantics></math>; (<b>d</b>) <math display="inline"><semantics> <mrow> <msub> <mi>p</mi> <mrow> <mi>v</mi> <mi>i</mi> <mi>r</mi> </mrow> </msub> <mo>=</mo> <mn>0.6</mn> </mrow> </semantics></math>.</p>
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<p>Testing time for different methods.</p>
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<p>Performance versus number of snapshots when <math display="inline"><semantics> <mrow> <mi>K</mi> <mo>=</mo> <mn>0</mn> </mrow> </semantics></math>; (<b>a</b>) PD of source number detection; (<b>b</b>) FAR of source number detection.</p>
Full article ">Figure 9
<p>Performance versus DOA of a single source; (<b>a</b>) PD of source number detection; (<b>b</b>) PMD of source number detection; (<b>c</b>) FAR of source number detection; (<b>d</b>) RMSE of DOA estimation based on the estimated number of sources.</p>
Full article ">Figure 10
<p>Performance versus SNR when <math display="inline"><semantics> <mrow> <mi>K</mi> <mo>=</mo> <mn>1</mn> </mrow> </semantics></math>; (<b>a</b>) PD of source number detection; (<b>b</b>) PMD of source number detection; (<b>c</b>) FAR of source number detection; (<b>d</b>) RMSE of DOA estimation based on the estimated number of sources.</p>
Full article ">Figure 11
<p>Performance versus number of snapshots when <math display="inline"><semantics> <mrow> <mi>K</mi> <mo>=</mo> <mn>1</mn> </mrow> </semantics></math>; (<b>a</b>) PD of source number detection; (<b>b</b>) PMD of source number detection; (<b>c</b>) FAR of source number detection; (<b>d</b>) RMSE of DOA estimation based on the estimated number of sources.</p>
Full article ">Figure 12
<p>Performance versus SNR when <math display="inline"><semantics> <mrow> <mi>K</mi> <mo>=</mo> <mn>2</mn> </mrow> </semantics></math>; (<b>a</b>) PD of source number detection; (<b>b</b>) PMD of source number detection; (<b>c</b>) FAR of source number detection; (<b>d</b>) RMSE of DOA estimation based on the estimated number of sources.</p>
Full article ">Figure 13
<p>Performance versus DOA separation when <math display="inline"><semantics> <mrow> <mi>K</mi> <mo>=</mo> <mn>2</mn> </mrow> </semantics></math>; (<b>a</b>) PD of source number detection; (<b>b</b>) PMD of source number detection; (<b>c</b>) FAR of source number detection; (<b>d</b>) RMSE of DOA estimation based on the estimated number of sources.</p>
Full article ">Figure 14
<p>Performance versus WNPR when <math display="inline"><semantics> <mrow> <mi>K</mi> <mo>=</mo> <mn>2</mn> </mrow> </semantics></math>, <math display="inline"><semantics> <mrow> <mi>S</mi> <mi>N</mi> <mi>R</mi> <mo>=</mo> <mo>−</mo> <mn>4</mn> </mrow> </semantics></math> dB, and <math display="inline"><semantics> <mrow> <mi>N</mi> <mo>=</mo> <mn>1000</mn> </mrow> </semantics></math>; (<b>a</b>) PD of source number detection; (<b>b</b>) PMD of source number detection; (<b>c</b>) FAR of source number detection; (<b>d</b>) RMSE of DOA estimation based on the estimated number of sources.</p>
Full article ">Figure 15
<p>Performance versus WNPR when <math display="inline"><semantics> <mrow> <mi>K</mi> <mo>=</mo> <mn>2</mn> </mrow> </semantics></math>, <math display="inline"><semantics> <mrow> <mi>S</mi> <mi>N</mi> <mi>R</mi> <mo>=</mo> <mo>−</mo> </mrow> </semantics></math>6 dB, and <math display="inline"><semantics> <mrow> <mi>N</mi> <mo>=</mo> <mn>100</mn> </mrow> </semantics></math>; (<b>a</b>) PD of source number detection; (<b>b</b>) PMD of source number detection; (<b>c</b>) FAR of source number detection; (<b>d</b>) RMSE of DOA estimation based on the estimated number of sources.</p>
Full article ">Figure 16
<p>Performance versus correlation coefficient when <math display="inline"><semantics> <mrow> <mi>K</mi> <mo>=</mo> <mn>2</mn> </mrow> </semantics></math>; (<b>a</b>) PD of source number detection; (<b>b</b>) PMD of source number detection; (<b>c</b>) FAR of source number detection; (<b>d</b>) RMSE of DOA estimation based on the estimated number of sources.</p>
Full article ">Figure 17
<p>Spatial spectrum of DNN-C for real data with source of <math display="inline"><semantics> <mrow> <msub> <mi>θ</mi> <mn>1</mn> </msub> <mo>=</mo> <mn>8</mn> <mo>°</mo> </mrow> </semantics></math> and an estimated SNR of 50 dB. The red dot with a red circle corresponds to the true DOA of source (i.e., 8°). The red dot with a black circle corresponds to the virtual peak.</p>
Full article ">Figure 18
<p>Normalized spatial spectra of conventional methods for real data with source of <math display="inline"><semantics> <mrow> <msub> <mi>θ</mi> <mn>1</mn> </msub> <mo>=</mo> <mn>8</mn> <mo>°</mo> </mrow> </semantics></math> and an estimated SNR of 50 dB. The blue cross corresponds to the true DOA of source (i.e., 8°).</p>
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<p>Spatial spectrum of DNN-C for real data with source of <math display="inline"><semantics> <mrow> <msub> <mi>θ</mi> <mn>1</mn> </msub> <mo>=</mo> <mn>8</mn> <mo>°</mo> </mrow> </semantics></math> and an estimated SNR of −10 dB; The red dot with a red circle corresponds to the true DOA of source (i.e., 8°). The red dot with a black circle corresponds to the virtual peak.</p>
Full article ">Figure 20
<p>Normalized spatial spectra of conventional methods for real data with source of <math display="inline"><semantics> <mrow> <msub> <mi>θ</mi> <mn>1</mn> </msub> <mo>=</mo> <mn>8</mn> <mo>°</mo> </mrow> </semantics></math> and an estimated SNR of −10 dB. The blue cross corresponds to the true DOA of source (i.e., 8°).</p>
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<p>Spatial spectrum of DNN-C for real data in the absence of the source. The red dot with a black circle corresponds to the virtual peak.</p>
Full article ">
14 pages, 2526 KiB  
Article
Reticulitermes flavipes (Blattodea: Rhinotermitidae) Response to Wood Mulch and Workers Mediated by Attraction to Carbon Dioxide
by Tae Young Henry Lee and P. Larry Phelan
Insects 2025, 16(2), 194; https://doi.org/10.3390/insects16020194 - 11 Feb 2025
Viewed by 330
Abstract
The eastern subterranean termite, Reticulitermes flavipes, is challenged by the significant energy expenditures of tunnel construction for resource discovery. Subterranean termites use idiothetic mechanisms to explore large spaces, while the use of resource-specific cues for localized search is disputed. Here, termite response [...] Read more.
The eastern subterranean termite, Reticulitermes flavipes, is challenged by the significant energy expenditures of tunnel construction for resource discovery. Subterranean termites use idiothetic mechanisms to explore large spaces, while the use of resource-specific cues for localized search is disputed. Here, termite response to wood mulch, termite workers, extracts of wood mulch, and CO2 alone were tested using a bioassay design that distinguished between attraction and arrestment. Termites showed significant attraction to wood mulch with workers or to wood mulch alone. They did not respond to workers alone at the initial dose tested, but were attracted to workers at higher densities. Termites did not respond to water or the acetone extracts of wood mulch, but did show a partial response to hexane extract compared to intact wood mulch. More significantly, when CO2 was removed from the emissions of wood mulch and workers using soda lime, attraction was eliminated. Furthermore, termites showed a quadratic response to CO2 concentration that peaked at ca. 14,000 ppm. The response to CO2 alone predicted by the model matched termite response to mulch + workers when compared at the level of CO2 they emitted. The results suggest that CO2 is both necessary and sufficient to explain the attraction response of R. flavipes to mulch and workers we observed. It is argued that orientation to food cues complements the previously demonstrated idiothetic program to maximize the efficiency of resource location. Full article
Show Figures

Figure 1

Figure 1
<p>Y-tube olfactometer design (<b>a</b>), with details of termite introduction chamber (<b>b</b>) and glass Y tube (<b>c</b>).</p>
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<p>Treatment chamber designs: (<b>a</b>) exit olfactometer, allowing for unrestricted movement; (<b>b</b>) no exit olfactometer, preventing exit upon entry; (<b>c</b>) no-exit olfactometer with a gap to contain soda lime, Drierite™, or nothing; and (<b>d</b>) no-exit olfactometer connected to a 500 mL syringe containing CO<sub>2</sub>.</p>
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<p>Response Index (RI) of termites presented with either a worker, mulch, or both by treatment and olfactometer design. The exit olfactometer allowed for unrestricted movement, whereas the no-exit olfactometer prevented exit from treatment chambers after entry. Asterisks indicate that the RI was different from 0 by a one-sample <span class="html-italic">t</span>-test (* 0.01 ≤ <span class="html-italic">p</span> &lt; 0.05, ** 0.001 ≤ <span class="html-italic">p</span> &lt; 0.01). Replication numbers (of 30 workers each) are shown within the bars.</p>
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<p>Response Index (RI) of termites presented one of three treatment doses, where 1× = 0.6 g mulch, 30 workers, or both. Asterisks on top indicate that the RI is significantly different from 0 by a one-sample <span class="html-italic">t</span>-test (* 0.01 ≤ <span class="html-italic">p</span> &lt; 0.05, ** 0.001 ≤ <span class="html-italic">p</span> &lt; 0.01; *** <span class="html-italic">p</span> &lt; 0.001). Asterisks on bottom indicate significant linear regression of the dose effect.</p>
Full article ">Figure 5
<p>Response Index (RI) of termites presented wood mulch or the extracts of wood mulch: (<b>a</b>) hexane or acetone extracts; and (<b>b</b>) hexane or distilled water extracts. Asterisks next to each error bar indicate that the RI is different from 0 by a one-sample <span class="html-italic">t</span>-test (* 0.01 ≤ <span class="html-italic">p</span> &lt; 0.05, ** 0.001 ≤ <span class="html-italic">p</span> &lt; 0.01; *** <span class="html-italic">p</span> &lt; 0.001). Different letters on the right indicate significant differences among treatments by protected LSD. Replication numbers (of 30 workers each) are shown within the bars.</p>
Full article ">Figure 6
<p>Mean number (±SE) of termites located in the Y-tube test chamber containing moist wood mulch (<b>a</b>), termite workers (<b>b</b>), or mulch + workers (<b>c</b>) compared to the control chamber. Middle section of the treatment chambers contained soda lime to remove CO<sub>2</sub>, spent Drierite™ as the control for the physical blockage of air movement, or nothing (Blank) as the positive control. Asterisks above bars indicate differences in termite numbers between chambers (* 0.01 ≤ <span class="html-italic">p</span> &lt; 0.05, ** 0.001 ≤ <span class="html-italic">p</span> &lt; 0.01, *** <span class="html-italic">p</span> &lt; 0.001, or ns = not significant) measured by the Kruskal–Wallis test (note: nonparametrics were used since RIs could not be normalized for this experiment). Letters to the right compare termite numbers in the test chamber among CO<sub>2</sub> removal treatments via the Kruskal–Wallis test. Replication numbers (of 30 workers each) are shown within the bars.</p>
Full article ">Figure 7
<p>Response Index of termites presented CO<sub>2</sub> concentrations from 1300 ppm to 430,000 ppm. The best-fit quadratic model is represented by the blue line with the greyed area encompassing the 95% CI. The orange point and bars represent the mean CO<sub>2</sub> emissions (±95% CI) (<span class="html-italic">x</span> axis) and Response Index (±95% CI) (<span class="html-italic">y</span> axis) for 1.2 g wood mulch + 60 termite workers.</p>
Full article ">
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