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34 pages, 116270 KiB  
Article
Methods for Quality Assessment of Window View
by Barbara Szybinska Matusiak, Filomena Russo, Mandana Sarey Khanie, Natalia Sokol, Christina Hemauer, Klaus Martiny, Carlo Volf, Siegrun Appelt, Natalia Giraldo Vasquez and Aicha Diakite-Kortlever
Land 2024, 13(12), 2090; https://doi.org/10.3390/land13122090 - 4 Dec 2024
Viewed by 1260
Abstract
This paper summarises findings from two workshops evaluating a series of views in various settings by an interdisciplinary group of experts. In the first one (Trondheim, June 2022), ten experts visited and assessed views from nine rooms. In the second one (Lausanne, June [...] Read more.
This paper summarises findings from two workshops evaluating a series of views in various settings by an interdisciplinary group of experts. In the first one (Trondheim, June 2022), ten experts visited and assessed views from nine rooms. In the second one (Lausanne, June 2023), eleven experts assessed window views from four spaces. The workshops’ main objective was to develop and test multi-method assessments of window views. During both workshops, participants completed a survey that included close and open-ended questions about the perceived quality of the room and the view. Participants also measured lux level, took photographs, made hand drawings of the view, and answered a questionnaire about their mood and the environmental conditions in the room. After the workshop, point-in-time daylight simulations were performed for the visited rooms. The paper describes, compares, and recommends the use of the aforementioned methods depending on the type and complexity of the view, and the space, the evaluators’ professional background, and the type of collected data. It also discusses the overlap of the methods and estimates the preparation time, time spent on site, and the amount of work after the visit. Finally, it recommends the use of the tested methods depending on the application. Full article
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9 pages, 877 KiB  
Proceeding Paper
Gait-Driven Pose Tracking and Movement Captioning Using OpenCV and MediaPipe Machine Learning Framework
by Malathi Janapati, Leela Priya Allamsetty, Tarun Teja Potluri and Kavya Vijay Mogili
Eng. Proc. 2024, 82(1), 4; https://doi.org/10.3390/ecsa-11-20470 - 26 Nov 2024
Viewed by 228
Abstract
Pose tracking and captioning are extensively employed for motion capturing and activity description in daylight vision scenarios. Activity detection through camera systems presents a complex challenge, necessitating the refinement of numerous algorithms to ensure accurate functionality. Even though there are notable characteristics, IP [...] Read more.
Pose tracking and captioning are extensively employed for motion capturing and activity description in daylight vision scenarios. Activity detection through camera systems presents a complex challenge, necessitating the refinement of numerous algorithms to ensure accurate functionality. Even though there are notable characteristics, IP cameras lack integrated models for effective human activity detection. With this motivation, this paper presents a gait-driven OpenCV and MediaPipe machine learning framework for human pose and movement captioning. This is implemented by incorporating the Generative 3D Human Shape (GHUM 3D) model which can classify human bones, while Python can classify the human movements as either usual or unusual. This model is fed into a website equipped with camera input, activity detection, and gait posture analysis for pose tracking and movement captioning. The proposed approach comprises four modules, two for pose tracking and the remaining two for generating natural language descriptions of movements. The implementation is carried out on two publicly available datasets, CASIA-A and CASIA-B. The proposed methodology emphasizes the diagnostic ability of video analysis by dividing video data available in the datasets into 15-frame segments for detailed examination, where each segment represents a time frame with detailed scrutiny of human movement. Features such as spatial-temporal descriptors, motion characteristics, or key point coordinates are derived from each frame to detect key pose landmarks, focusing on the left shoulder, elbow, and wrist. By calculating the angle between these landmarks, the proposed method classifies the activities as “Walking” (angle between −45 and 45 degrees), “Clapping” (angles below −120 or above 120 degrees), and “Running” (angles below −150 or above 150 degrees). Angles outside these ranges are categorized as “Abnormal”, indicating abnormal activities. The experimental results show that the proposed method is robust for individual activity recognition. Full article
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13 pages, 5424 KiB  
Article
Zonal Reconstruction of Daylighting in Historic Built Environments: A Workflow to Model and Evaluate Light in Spatial and Temporal Domains
by Lars Oliver Grobe, Andreas Noback, Stephen William Wasilewski and Claudia Mächler
Heritage 2024, 7(11), 5963-5975; https://doi.org/10.3390/heritage7110279 - 22 Oct 2024
Viewed by 1172
Abstract
Computer simulation allows to study daylight conditions in the past that afforded activities in antique buildings. The Python module phos4dtools implements the efficient computation of zonal daylight metrics that are considered to indicate affordances. It was employed to solve horizontal and vertical illuminance [...] Read more.
Computer simulation allows to study daylight conditions in the past that afforded activities in antique buildings. The Python module phos4dtools implements the efficient computation of zonal daylight metrics that are considered to indicate affordances. It was employed to solve horizontal and vertical illuminance for different orientations and elevations in the House of the Priestesses, a unit of the Hadrianic Garden Houses complex in Ostia. A reconstruction model of the unit was produced by collating an existing, detailed 3D documentation with other sources and our own survey data. The spatially and temporally resolved results of daylight simulation employing phos4dtools were imported into a GIS database. Assuming typical reflectance properties, illuminance thresholds were determined that are required for the perception of contrast detail and colour differences. Integration over temporal periods and spatial zones that are eligible for residential activities was implemented by queries to the database. First, preliminary results indicated different distributions of affordances by daylight, depending on the characteristics of the considered visual tasks. Horizontal illuminance decreases quickly with increasing distance to the aperture, suggesting that activities bound to a horizontal work plane were constraint to the immediate adjacency of windows and potentially open doors. Vertical illuminance, on the other hand, reaches deep into the building when the receiving surface is oriented to a window, particularly in the absence of exterior obstructions. The exemplary application of phos4dtools shows its potential in the interdisciplinary research on daylight and its implications on living practice in antique buildings. Full article
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17 pages, 3459 KiB  
Article
Performance Analysis of a Color-Code-Based Optical Camera Communication System
by Hasan Ziya Dinc and Yavuz Erol
Appl. Sci. 2024, 14(19), 9102; https://doi.org/10.3390/app14199102 - 8 Oct 2024
Viewed by 818
Abstract
In this study, we present a visible light communication (VLC) system that analyzes the performance of an optical camera communication (OCC) system, utilizing a mobile phone camera as the receiver and a computer monitor as the transmitter. By creating color channels in the [...] Read more.
In this study, we present a visible light communication (VLC) system that analyzes the performance of an optical camera communication (OCC) system, utilizing a mobile phone camera as the receiver and a computer monitor as the transmitter. By creating color channels in the form of a 4 × 4 matrix within a frame, we determine the parameters that affect the successful transmission of data packets. Factors such as the brightness or darkness of the test room, the light color of the lamp in the illuminated environment, the effects of daylight when the monitor is positioned in front of a window, and issues related to dead pixels and light bleed originating from the monitor’s production process have been considered to ensure accurate data transmission. In this context, we utilized the PyCharm, Pydroid, Python, Tkinter, and OpenCV platforms for programming the transmitter and receiver units. Through the application of image processing techniques, we mitigated the effects of daylight on communication performance, thereby proposing a superior system compared to standard VLC systems that incorporate photodiodes. Additionally, considering objectives such as the maximum number of channels and the maximum distance, we regulated the sizes of the channels, the distances between the channels, and the number of channels. The NumPy library, compatible with Python–Tkinter, was employed to determine the color levels and dimensions of the channels. We investigate the effects of RGB and HSV color spaces on the data transmission rate and communication distance. Furthermore, the impact of the distance between color channels on color detection performance is discussed in detail. Full article
(This article belongs to the Section Electrical, Electronics and Communications Engineering)
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34 pages, 9166 KiB  
Article
Enhancing Daylight Comfort with Climate-Responsive Kinetic Shading: A Simulation and Experimental Study of a Horizontal Fin System
by Marcin Brzezicki
Sustainability 2024, 16(18), 8156; https://doi.org/10.3390/su16188156 - 19 Sep 2024
Viewed by 1636
Abstract
This study employs both simulation and experimental methodologies to evaluate the effectiveness of bi-sectional horizontal kinetic shading systems (KSS) with horizontal fins in enhancing daylight comfort across various climates. It emphasizes the importance of optimizing daylight levels while minimizing solar heat gain, particularly [...] Read more.
This study employs both simulation and experimental methodologies to evaluate the effectiveness of bi-sectional horizontal kinetic shading systems (KSS) with horizontal fins in enhancing daylight comfort across various climates. It emphasizes the importance of optimizing daylight levels while minimizing solar heat gain, particularly in the context of increasing energy demands and shifting climatic patterns. The study introduces a custom-designed bi-sectional KSS, simulated in three distinct climates—Wroclaw, Tehran, and Bangkok—using climate-based daylight modeling methods with the Ladybug and Honeybee tools in Rhino v.7 software. Standard daylight metrics, such as Useful Daylight Illuminance (UDI) and Daylight Glare Probability (DGP), were employed alongside custom metrics tailored to capture the unique dynamics of the bi-sectional KSS. The results were statistically analyzed using box plots and histograms, revealing UDI300–3000 medians of 78.51%, 88.96%, and 86.22% for Wroclaw, Tehran, and Bangkok, respectively. These findings demonstrate the KSS’s effectiveness in providing optimal daylight conditions across diverse climatic regions. Annual simulations based on standardized weather data showed that the KSS improved visual comfort by 61.04%, 148.60%, and 88.55%, respectively, compared to a scenario without any shading, and by 31.96%, 54.69%, and 37.05%, respectively, compared to a scenario with open static horizontal fins. The inclusion of KSS switching schedules, often overlooked in similar research, enhances the reproducibility and clarity of the findings. A physical reduced-scale mock-up of the bi-sectional KSS was then tested under real-weather conditions in Wroclaw (latitude 51° N) during June–July 2024. The mock-up consisted of two Chambers ‘1’ and ‘2’ equipped with the bi-sectional KSS prototype, and the other one without shading. Stepper motors managed the fins’ operation via a Python script on a Raspberry Pi 3 minicomputer. The control Chamber ‘1’ provided a baseline for comparing the KSS’s efficiency. Experimental results supported the simulations, demonstrating the KSS’s robustness in reducing high illuminance levels, with illuminance below 3000 lx maintained for 68% of the time during the experiment (conducted from 1 to 4 PM on three analysis days). While UDI and DA calculations were not feasible due to the limited number of sensors, the Eh1 values enabled the evaluation of the time illuminance to remain below the threshold. However, during the June–July 2024 heat waves, illuminance levels briefly exceeded the comfort threshold, reaching 4674 lx. Quantitative and qualitative analyses advocate for the broader application and further development of KSS as a climate-responsive shading system in various architectural contexts. Full article
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10 pages, 1252 KiB  
Article
Effect of Different Post-Flowering Photoperiods on Main Agronomic Traits of Strawberry (Fragaria × ananassa Duch. cv. Akihime)
by Cai Ren, Lamei Jiang, Weizhi Chen and Ziyi Wang
Agronomy 2024, 14(9), 2039; https://doi.org/10.3390/agronomy14092039 - 6 Sep 2024
Cited by 1 | Viewed by 855
Abstract
Reproductive growth is one of the most important stages in the life history of plants and is regulated by photoperiod. However, the effect of different photoperiods after flowering on the reproductive growth stages of different plants and their roles is still unclear. For [...] Read more.
Reproductive growth is one of the most important stages in the life history of plants and is regulated by photoperiod. However, the effect of different photoperiods after flowering on the reproductive growth stages of different plants and their roles is still unclear. For this reason, this study took the short-day plant strawberry (Fragaria × ananassa Duch. cv. Akihime) as the research object, performed different photoperiod treatments (ND: natural daylight; SD: short daylight; LD: long daylight) after flowering, and studied the effects of photoperiod on fruit growth period, fruit quality, flower opening, and plant height in different inflorescence of fruits. The results showed that different photoperiods had significantly different effects on the growth and development of strawberries after flowering, and LD and SD had opposite effects: (1) Under the condition of SD, the fruit matured after 17 days of treatment, while the LD and ND advanced this by 6 and 5 days. LD could significantly delay the development of the first inflorescence of fruits, resulting in longer ripening period and fruit appearance, and the quality traits were better. (2) The number of flowers in the secondary inflorescence and the development process was effectively accelerated by LD, and the total number of flowers under the long-day treatment was significantly more than that under the short-day treatment and the natural condition from 12 to 25 days after the end of the flowering period. Under the condition of LD, the fruits matured after 53 days of treatment, which was 5 days earlier than the other two treatments, and the period from flowering to maturity was shortened. (3) The effect of different photoperiods on the final plant height of strawberries after flowering had no significant difference (p < 0.05). In conclusion, this study found that photoperiod could effectively regulate the reproductive growth stage of strawberry after flowering, which enriched the experimental material and theoretical basis for studying the photoperiod as a mechanism for regulating plant growth and development, providing technical guidance for artificial regulation of strawberry growth period and fruit quality. Full article
(This article belongs to the Section Horticultural and Floricultural Crops)
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17 pages, 3834 KiB  
Article
Research on Opening Design Guidelines for Zero-Energy House Based on the Family Life Cycle
by Xun Sun, Dekun Dong, Yang Yang and Yifan Dong
Buildings 2024, 14(9), 2700; https://doi.org/10.3390/buildings14092700 - 29 Aug 2024
Viewed by 634
Abstract
Spatial resources and environmental problems caused by population growth are increasingly becoming the focus of global concern. The environmental sustainability of building products has become the research frontier of the industry. Previous research has proved that 25% of energy consumption comes from daily [...] Read more.
Spatial resources and environmental problems caused by population growth are increasingly becoming the focus of global concern. The environmental sustainability of building products has become the research frontier of the industry. Previous research has proved that 25% of energy consumption comes from daily use, and realizing low-energy design based on the whole life cycle is of great significance to promoting the transformation of the building industry. This paper focuses on the wasteful energy consumption problem caused by the changes in residents’ behavioral requirements due to the changes in family structure. Based on the family life cycle analysis, this paper explores the mechanism of residents’ behavioral requirements and spatial function changes at each stage to clarify the relationship between residents’ behavior and building energy consumption. Then, by controlling factors, including Light Correction Coefficient, Effective Daylight Area, window-to-ground ratio, and window-to-wall ratio, and applying the passive design methodology, this paper establishes the zero-energy home opening design guidelines based on the family life cycle. This research guides designers in the design of zero-energy house openings and, at the same time, provides new perspectives for related research in the field of building energy consumption, which helps to promote the sustainable development of the field of architectural design. Full article
(This article belongs to the Section Building Energy, Physics, Environment, and Systems)
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17 pages, 5379 KiB  
Article
The Evolving Theme of Health-Promoting Urban Form: Applying the Macrolot Concept for Easy Access to Open Public Green Spaces
by Monika Trojanowska
Urban Sci. 2024, 8(3), 115; https://doi.org/10.3390/urbansci8030115 - 15 Aug 2024
Viewed by 768
Abstract
Making cities health-promoting places is an evolving theme. Numerous studies confirm the health-promoting qualities of contact with nature and problems resulting from the deprivation of access to public green spaces. Easy access to safe and inclusive public green spaces is still one of [...] Read more.
Making cities health-promoting places is an evolving theme. Numerous studies confirm the health-promoting qualities of contact with nature and problems resulting from the deprivation of access to public green spaces. Easy access to safe and inclusive public green spaces is still one of the long-lasting problems of urbanized areas around the globe. It is one of the sustainable development goals, SDGs, proposed by the UN: 11. Make cities and human settlements inclusive, safe, resilient and sustainable. Point 11.7 By 2030, provide universal access to safe, inclusive and accessible, green and public spaces, in particular for women and children, older persons and persons with disabilities. The major question is how to implement this goal in practice and design cities to provide easy access to safe and inclusive public green spaces. One of the important concepts for sustainable urban development is the urban block, Macrolot, coined by Christian de Portzamparc, which led to the new urban morphology of eco-neighborhoods in France. It combines the traditional, walkable urban grid with the Le Corbusier vision for a healthy modernist city offering daylight, fresh air, and greenery for everyone. Among the advantages of this particular urban morphology are the increased presence of green spaces and possibilities for placemaking. Studying the effects of the urban form of the Macrolot is of great significance for sustainable urban development. In this study, five neighborhoods—three eco-neighborhoods from France designed according to the open urban block, Macrolot urban morphology, ZAC Massena, ZAC Trapeze, and ZAC Clichy-Batignolles, and two award-winning developments from Poland, Riverview and Ostoja Wilanów—were chosen as case studies. The application of the Macrolot concept to sustainable urban planning and design and the possibilities for operationalization of the SDG—11. Make cities and human settlements inclusive, safe, resilient and sustainable—are discussed. This study offers valuable evidence to inform urban planning and design. Full article
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12 pages, 3148 KiB  
Proceeding Paper
Evaluation of Cloud-Based Dynamic Network Scaling and Slicing for Next-Generation Wireless Networks
by Aykut Cubukcu, Ozlem Cubukcu, Adnan Kavak and Kerem Kucuk
Eng. Proc. 2024, 70(1), 45; https://doi.org/10.3390/engproc2024070045 - 12 Aug 2024
Viewed by 599
Abstract
The relentless growth of wireless networks coupled with the burgeoning demand for dynamic resource allocation has spurred research into innovative solutions. This paper presents an evaluation of Cloud-based Dynamic Network Scaling and Slicing (CDNSS) as a promising approach to meet the evolving demands [...] Read more.
The relentless growth of wireless networks coupled with the burgeoning demand for dynamic resource allocation has spurred research into innovative solutions. This paper presents an evaluation of Cloud-based Dynamic Network Scaling and Slicing (CDNSS) as a promising approach to meet the evolving demands of wireless networks. By leveraging cloud infrastructure and slicing techniques, CDNSS offers the flexibility to dynamically scale resources and allocate network slices tailored to diverse service requirements. The evaluation encompasses the performance of CDNSS in terms of scalability, resource utilisation and Quality of Service (QoS) provisioning. Through extensive simulations and analyses, the efficacy of CDNSS in addressing the challenges of resource management and service differentiation in wireless networks is demonstrated. The findings underscore the potential of CDNSS as a pivotal technology to enhance the efficiency and adaptability of wireless network architectures in the era of dynamic connectivity demands. Full article
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18 pages, 1035 KiB  
Article
Impact of Southbound Expansion on Clustered OpenFlow Software-Defined Network Controller Synchronisation Using ODL and ONOS
by Egodahettiarachchige Don Sarada Indumini Hettiarachchi, Nurul I. Sarkar and Jairo Gutierrez
Information 2024, 15(8), 440; https://doi.org/10.3390/info15080440 - 29 Jul 2024
Viewed by 1152
Abstract
The clustering methods of Software-Defined Networking (SDN) have gained popularity due to their ability to offer improved scalability, consistency, dependability, and load balancing within overlay networks and SDN partitions. This paper delved into the effects of increasing the number of OpenFlow-enabled southbound devices [...] Read more.
The clustering methods of Software-Defined Networking (SDN) have gained popularity due to their ability to offer improved scalability, consistency, dependability, and load balancing within overlay networks and SDN partitions. This paper delved into the effects of increasing the number of OpenFlow-enabled southbound devices on the establishment and coordination of SDN-controller clusters. Specifically, we examined the volume of east–west cluster packet communications concerning the number of southbound devices within the topology. Many research studies have focused on bandwidth and the number of bytes in east–west communication. While bandwidth refers to the maximum rate at which data can be transferred, and the number of bytes reflects the volume of data being transmitted, the number of packet communications directly influences the efficiency and responsiveness of network operations. Our investigation encompassed the impact of SDN controller-to-controller communication within the cluster concerning the rising number of OpenFlow switches connected to various topologies, including tree (star-bus network), linear, and torus configurations. This study provided data on communication patterns within Open Network Operating Systems (ONOS) and OpenDaylight (ODL) clusters, revealing differing levels of controller communication with southbound network expansions. We evaluated the scalability of ODL and ONOS controllers by scrutinising the effect of increasing the number of southbound devices on the control communication volume. Our analysis revealed varied communication patterns within ONOS and ODL clusters, resulting in different volumes of control communication with southbound expansions. The findings indicated that in small-to-medium-sized SDNs, ODL outperformed ONOS, notably with faster cluster discovery. Conversely, ONOS demonstrated greater efficiency in larger networks owing to its centralised communication architecture. Finally, we provide recommendations for selecting the most suitable controllers based on the size of southbound networks, aiming to provide practical guidelines for optimal network performance. Full article
(This article belongs to the Special Issue Wireless IoT Network Protocols II)
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16 pages, 8394 KiB  
Article
Design of a Low-Cost Open-Top Chamber Facility for the Investigation of the Effects of Elevated Carbon Dioxide Levels on Plant Growth
by Nicola Novello, Mani Naiker, Haydee Laza, Kerry B. Walsh and Sabine Tausz-Posch
Hardware 2024, 2(2), 138-153; https://doi.org/10.3390/hardware2020007 - 15 May 2024
Cited by 1 | Viewed by 2043
Abstract
Open-top chambers (OTCs) consist of semi-open enclosures used to investigate the impact of elevated carbon dioxide [CO2] on crops and larger plant communities. OTCs have lower operational costs than alternatives such as controlled environment cabinets and Free Air Carbon Dioxide Enrichment [...] Read more.
Open-top chambers (OTCs) consist of semi-open enclosures used to investigate the impact of elevated carbon dioxide [CO2] on crops and larger plant communities. OTCs have lower operational costs than alternatives such as controlled environment cabinets and Free Air Carbon Dioxide Enrichment (FACE). A low-cost design is presented for an OTC with a surface area of 1.2 m2 and a target elevated CO2 concentration [CO2] of 650 µmol mol−1 adequate for trials involving cereals or grain legumes. The elevated CO2 chambers maintained an average concentration ± standard deviation of 652 ± 37 µmol mol−1 despite wind and air turbulences, in comparison to 407 ± 10 µmol mol−1 for non-enriched chambers. Relative to ambient (non-chamber) conditions, plants in the chambers were exposed to slightly warmer conditions (2.3 °C in daylight hours; 0.6 °C during night environment). The materials’ cost for constructing the chambers was USD 560 per chamber, while the CO2 control system for four chambers dedicated to CO2-enriched conditions cost USD 5388. To maintain the concentration of 650 µmol mol−1 during daylight hours, each chamber consumed 1.38 L min−1 of CO2. This means that a size G CO2 cylinder was consumed in 8–9 days in the operation of two chambers (at USD 40). Full article
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19 pages, 11612 KiB  
Article
Genetic Algorithm-Driven Optimization of Pattern for Parametric Facade Design Based on Support Position Data to Increase Visual Quality
by Mojgan Rezakhani and Sung-Ah Kim
Buildings 2024, 14(4), 1086; https://doi.org/10.3390/buildings14041086 - 13 Apr 2024
Cited by 2 | Viewed by 1636
Abstract
One of the most critical challenges for architects in façade design is providing an effective view from the indoors to the outdoors of a building for users, although the main role of the parametric façade is covering openings to control daylight and temperature. [...] Read more.
One of the most critical challenges for architects in façade design is providing an effective view from the indoors to the outdoors of a building for users, although the main role of the parametric façade is covering openings to control daylight and temperature. This study uses a genetic algorithm to optimize and evaluate the number and place of nodes and the position of supports required for a parametric façade based on the geometric patterns. Using the dataset with genetic algorithms is effective in reducing or replacing the nodes and supports of the façade. It also creates broader and irregular patterns just around the windows, which decreases the visual disturbance experienced by occupants. Accordingly, optimal building facade operation in terms of both building aesthetics and performance is important. The method used in this study, validated through three geometric grid patterns based on node positions, can be used to analyze dataset-incorporated patterns for potential irregular façade extensions. The nodes are considered by analyzing the cross-section optimization using the Galapagos program, and then data are obtained with Karamba based on reaction force, node force, and the deformation energy. The results show that among the three grid patterns, i.e., triangular, square, and hexagonal, the hexagonal grid is most efficient, exhibiting up to 60% lower reaction force, 40% lower node force, and 30% less deformation energy than the square grid pattern. The proposed GA also shows its effectiveness in enhancing the performance of parametric façades with patterns, thereby improving the occupants’ visual experience. Full article
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27 pages, 3424 KiB  
Review
A Qualitative and Comparative Performance Assessment of Logically Centralized SDN Controllers via Mininet Emulator
by Mohammad Nowsin Amin Sheikh, I-Shyan Hwang, Muhammad Saibtain Raza and Mohammad Syuhaimi Ab-Rahman
Computers 2024, 13(4), 85; https://doi.org/10.3390/computers13040085 - 25 Mar 2024
Cited by 3 | Viewed by 2511
Abstract
An alternative networking approach called Software Defined Networking (SDN) enables dynamic, programmatically efficient network construction, hence enhancing network performance. It splits a traditional network into a centralized control plane and a configurable data plane. Because the core component overseeing every data plane action [...] Read more.
An alternative networking approach called Software Defined Networking (SDN) enables dynamic, programmatically efficient network construction, hence enhancing network performance. It splits a traditional network into a centralized control plane and a configurable data plane. Because the core component overseeing every data plane action is the controller in the control plane, which may contain one or more controllers and is thought of as the brains of the SDN network, controller functionality and performance are crucial to achieve optimal performances. There is much controller research available in the existing literature. Nevertheless, no qualitative comparison study of OpenFlow-enabled distributed but logically centralized controllers exists. This paper includes a quantitative investigation of the performance of several distributed but logically centralized SDN controllers in custom network scenarios using Mininet, as well as a thorough qualitative comparison of them. More precisely, we give a qualitative evaluation of their attributes and classify and categorize 13 distributed but logically centralized SDN controllers according to their capabilities. Additionally, we offer a comprehensive SDN emulation tool, called Mininet-based SDN controller performance assessment, in this study. Using six performance metrics—bandwidth, round-trip time, delay, jitter, packet loss, and throughput—this work also assesses five distributed but logically centralized controllers within two custom network scenarios (uniform and non-uniform host distribution). Our analysis reveals that the Ryu controller outperforms the OpenDayLight controller in terms of latency, packet loss, and round-trip time, while the OpenDayLight controller performs well in terms of throughput, bandwidth, and jitter. Throughout the entire experiment, the HyperFlow and ONOS controllers performed worst in all performance metrics. Finally, we discuss detailed research findings on performance. These experimental results provide decision-making guidelines when selecting a controller. Full article
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17 pages, 3244 KiB  
Article
The Energy Saving Potential in an Office Building Using Louvers in Mid-Latitude Climate Conditions
by Ngoc-Minh Kieu, Irfan Ullah, Jongbin Park, Hojune Bae, Meeryoung Cho, Keonwoo Lee and Seoyong Shin
Buildings 2024, 14(2), 512; https://doi.org/10.3390/buildings14020512 - 13 Feb 2024
Cited by 3 | Viewed by 2038
Abstract
Daylighting has emerged as a prominent strategy for elevating indoor environments by harmonizing visual comfort and energy efficiency. This paper introduces a louver system crafted for energy simulations, specifically tailored to address lighting and cooling requirements in office spaces. Louvers, acknowledged for their [...] Read more.
Daylighting has emerged as a prominent strategy for elevating indoor environments by harmonizing visual comfort and energy efficiency. This paper introduces a louver system crafted for energy simulations, specifically tailored to address lighting and cooling requirements in office spaces. Louvers, acknowledged for their exceptional efficiency in providing daylight, are integrated as a pivotal energy-saving technique. Adopting a quantitative research approach facilitated by building information simulation tools, DIALUX evo and Rhino were employed for modeling and simulating the building’s daylighting performances. The simulation outcomes reveal substantial energy savings, particularly in the realms of lighting and cooling. Notably, a 50% louver opening in office spaces results in an impressive 27.0% reduction in energy consumption. The study explores various louver configurations, providing insights into both lighting and cooling energy savings. The overall system performance excels in sustaining consistent daylight, significantly contributing to enhanced energy efficiency. Full article
(This article belongs to the Section Building Energy, Physics, Environment, and Systems)
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17 pages, 1763 KiB  
Article
Green Residential Building Design Scheme Optimization Based on the Orthogonal Experiment EWM-TOPSIS
by Honghua Chen and Yun-ce An
Buildings 2024, 14(2), 452; https://doi.org/10.3390/buildings14020452 - 6 Feb 2024
Cited by 5 | Viewed by 1198
Abstract
A multi-objective decision method is proposed based on the combining orthogonal test, entropy weight method (EWM) with TOPSIS (technique for order preference by similarity to an ideal solution) in this article. The method is more objective and efficient than traditional methods in the [...] Read more.
A multi-objective decision method is proposed based on the combining orthogonal test, entropy weight method (EWM) with TOPSIS (technique for order preference by similarity to an ideal solution) in this article. The method is more objective and efficient than traditional methods in the design of green residential buildings. A villa in Nanjing was taken as an example, and the cost, building energy consumption, and daylight factors were used as decision-making indexes. A total of six control factors were selected: terrain elevation, window area, building orientation, the opening ratio of exterior windows, roof structure, and window glass material. Each factor was designed with three levels. First, a design scheme index system was constructed, and the orthogonal experimental design was used to select representative design schemes. Then, the EWM and the TOPSIS method were used to determine the weight of each index, a comprehensive evaluation of the residential building design scheme was conducted, and, finally, the optimal scheme was confirmed via range analysis. The results show that the multi-objective decision-making model based on the orthogonal experiment EWM-TOPSIS is suitable for green residential building design and the optimal solution obtained is “15 m elevation, a 1200 × 1500 mm size vacuum glass, an orientation of 170° and an external window opening ratio 45% with a 40 mm thick expanded insulation board roof”. Full article
(This article belongs to the Section Construction Management, and Computers & Digitization)
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