Control System for Indoor Safety Measures Using a Faster R-CNN Architecture

This paper presents a control system for indoor safety measures using a Faster R-CNN (Region-based Convolutional Neural Network) architecture. The proposed system aims to ensure the safety of occupants in indoor environments by detecting and recognizing potential safety hazards in real time, such as capacity control, social distancing, or mask use. Using deep learning techniques, the system detects these situations to be controlled, notifying the person in charge of the company if any of these are violated. The proposed system was tested in a real teaching environment at Rey Juan Carlos University, using Raspberry Pi 4 as a hardware platform together with an Intel Neural Stick board and a pair of PiCamera RGB (Red Green Blue) cameras to capture images of the environment and a Faster R-CNN architecture to detect and classify objects within the images. To evaluate the performance of the system, a dataset of indoor images was collected and annotated for object detection and classification. The system was trained using this dataset, and its performance was evaluated based on precision, recall, and F1 score. The results show that the proposed system achieved a high level of accuracy in detecting and classifying potential safety hazards in indoor environments. The proposed system includes an efficiently implemented software infrastructure to be launched on a low-cost hardware platform, which is affordable for any company, regardless of size or revenue, and it has the potential to be integrated into existing safety systems in indoor environments such as hospitals, warehouses, and factories, to provide real-time monitoring and alerts for safety hazards. Future work will focus on enhancing the system's robustness and scalability to larger indoor environments with more complex safety hazards.

Evaluation of a Low-Cost Air Renewal System for Indoor Air Quality Control in a Climate Chamber

There is a growing concern about Indoor Environmental Quality (IEQ) in buildings as humans are spending longer in indoor environments, whether this is associated or not with climate change and vulnerability to extreme weather events. In the wake of the COVID pandemic, the need for indoor air quality control is likely to increase, the result of many adaptations in home environments to switch to remote work. In hot countries in the Global South, one of the alternatives is split A/C units with limited air renewal. While, odorless and colorless CO2, commonly generated by occupants through respiration, is among the relevant indoor air pollutants. The purpose of this study is to evaluate a low-cost, responsive air-renewal system in a climate chamber equipped with a standard split A/C unit. The results show the system's feasibility in curbing IAQ concerns and also highlight the risk of negative impacts on indoor thermal conditions and on energy consumption on using A/C. © 2023, The Author(s), under exclusive license to Springer Nature Switzerland AG.

Joint Transmission Scheme and Coded Content Placement in Cluster-Centric UAV-Aided Cellular Networks

Recently, as a consequence of the COVID-19 pandemic, dependence on telecommunication for remote learning/working and telemedicine has significantly increased. In this context, preserving high Quality of Service (QoS) and maintaining low-latency communication are of paramount importance. In cellular networks, the incorporation of unmanned aerial vehicles (UAVs) can result in enhanced connectivity for outdoor users due to the high probability of establishing Line of Sight (LoS) links. The UAV's limited battery life and its signal attenuation in indoor areas, however, make it inefficient to manage users' requests in indoor environments. Referred to as the cluster-centric and coded UAV-aided femtocaching (CCUF) framework, the network's coverage in both indoor and outdoor environments increases by considering a two-phase clustering framework for Femto access points (FAPs)' formation and UAVs' deployment. Our first objective is to increase the content diversity. In this context, we propose a coded content placement in a cluster-centric cellular network, which is integrated with the coordinated multipoint (CoMP) approach to mitigate the intercell interference in edge areas. Then, we compute, experimentally, the number of coded contents to be stored in each caching node to increase the cache-hit-ratio, signal-to-interference-plus-noise ratio (SINR), and cache diversity and decrease the users' access delay and cache redundancy for different content popularity profiles. Capitalizing on clustering, our second objective is to assign the best caching node to indoor/outdoor users for managing their requests. In this regard, we define the movement speed of ground users as the decision metric of the transmission scheme for serving outdoor users' requests to avoid frequent handovers between FAPs and increase the battery life of UAVs. Simulation results illustrate that the proposed CCUF implementation increases the cache-hit-ratio, SINR, and cache diversity and decrease the users' access delay, cache redundancy, and UAVs' energy consumption.

Barriers to incorporation of indoor environmental quality (IEQ) principles into building designs

PurposeThis research presents a comprehensive review of the literature on the barriers to incorporating indoor environmental quality (IEQ) principles into building designs. The aim was to identify these barriers in the literature and subsume them under broad categories for the development of a framework showing the interrelationships among the barriers.Design/methodology/approachThe research design used a systematic desktop review which comprised of three levels of screening. The first level allowed for a broad selection of papers;the second level of screening was done to limit the results to papers within the construction industry, and the third level of screening limited the documents strictly to the publication period of 2000–2021.FindingsTwenty-four (24) barriers were identified in the literature, including lack of integrated design teams, which ranked the highest in appearance, high initial costs, poor market for IEQ buildings and higher design charges among others. The identified barriers were classified into six (6) categories namely capacity barriers, economic barriers, process-related barriers, cultural barriers, client-related barriers and steering barriers.Practical implicationsThe findings of this study would enable practitioners and policymakers to better understand what is preventing the widespread adoption of IEQ designs in the built environment and devise actionable strategies to overcome them. It adds to the body of knowledge on IEQ research by categorizing the various barriers that prevent the delivery of IEQ projects.Social implicationsThe developed barriers in this research can serve as a useful checklist to future researchers who may want to validate the barriers to IEQ designs in empirical studies and in different settings.Originality/valueThe interconnectivity revealed by the web-like framework allows for an appreciation of the various barriers of IEQ adoption which would help in expanding the current knowledge on IEQ beyond the narrow scope of isolated barriers. The fact that the papers selected in this study are not limited geographically, underscores the wide applicability of the findings in the global construction industry.

Evaluation of Optimal Mechanical Ventilation Strategies for Schools for Reducing Risks of Airborne Viral Infection

Ventilation systems are one of the most effective strategies to reduce the risk of viral infection transmission in buildings. However, insufficient ventilation rates in crowded spaces, such as schools, would lead to high risks of infection transmission. On the other hand, excessive ventilation rates might significantly increase cooling energy consumption. Therefore, energy-efficient control methods, such as Demand Control Ventilation systems (DCV), are typically considered to maintain acceptable indoor air quality. However, it is unclear if the DCV-based controls can supply adequate ventilation rates to minimize the probability of infection (POI) in indoor spaces. This paper investigates the benefits of optimized ventilation strategies, including conventional mechanical systems (MV) and DCV, in reducing the POI and cooling energy consumption through a detailed sensitivity analysis. The study also evaluates the impact of the ventilation rate, social distancing, and number of infectors on the performance of the ventilation systems. A coupling approach of a calibrated energy model of a school building in Jeddah, KSA, with a validated Wells–Riley model is implemented. Based on the findings of this study, proper adjustment of the DCV set point is necessary to supply adequate ventilation rates and reduce POI levels. Moreover, optimal values of 2 ACH for ventilation rate and 2 m for social distance are recommended to deliver acceptable POI levels, cooling energy use, and indoor CO2 concentration for the school building. Finally, this study confirms that increasing the ventilation rate is more effective than increasing social distancing in reducing the POI levels. However, this POI reduction is achieved at the cost of a higher increase in the cooling energy.

Psychological State and Subjective Environmental Perception of College Students Residing in Dormitories during Quarantine: A Case Study

Quarantine is one of the effective approaches to control the spread of COVID-19. However, prolonged isolation may harm the health of residents, especially students, who are quarantined in dormitories. This study surveyed students' behaviors, living environment, and psychological state through an online questionnaire. The results showed that during the isolation period, the participants' discomfort mainly came from high temperatures, high humidity, loud sounds, and dark lighting. Moreover, about half of the students experienced severe anxiety or depression, with poor sleep and an unclear mind being the most common problems. Additionally, this study focused on exploring the correlations between environmental perceptions and the psychological state of isolated students, that were identified to be significant. Furthermore, as isolation time was prolonged, the psychological state of isolated students worsened, and the most significant factor changed from thermal sensations to acoustic sensations. Interestingly, the psychological state of males was worse than females, and they were more easily affected by their thermal and acoustic environments. Therefore, keeping the environment comfortable has a positive influence on maintaining the good psychological condition of people in isolation. This study can provide suggestions for the improvement of indoor environments and for the mental health of people in isolation and in other similar situations.

Effects of Visitor Influx on the Indoor Climate of the Milan Cathedral

The indoor climate of non-climatized churches is usually subject to cyclical fluctuations of temperature and relative humidity induced by external climate conditions which might be dampened by the high thermal capacity of their envelope. However, several phenomena affect their indoor climate (e.g., internal gains due to people and artificial lighting, air infiltration, etc.), which lead to environmental variations that might jeopardize the artworks contained within. In particular, one of the most influential parameters that may affect non-climatized churches is the massive and intermittent presence of people who constantly visit their spaces. In such regard, long-term monitoring allows the collection of environmental data with different building operation conditions and visitor fluxes. This paper analyses the indoor climate of the Milan Cathedral (Duomo di Milano) in Italy for three continuous years (including the lockdown period that occurred in 2020 caused by the COVID-19 pandemic), with a focus on visitors' effects on the indoor environment and the conservation of the main artworks contained within. The results of the analysis have shown that spaces with huge volume are most influenced by the opening of the doors rather than the hygrothermal contribution of the intermittent presence of massive crowds. Moreover, the absence of visitors for a prolonged period correlates with an improvement in the indoor conservation conditions for artworks, especially those made of hygroscopic materials, due to the reduction in short, rapid climate fluctuations.

Breakthrough infection among workers in different non-healthcare working settings

IntroductionWorkplace is supposed to be an important transmission node of coronavirus disease-2019 (COVID-19) in the epic initiation. Assessing the contagious risk in the different workplaces is important to target effective measures workplace. However, there was limited data to explore transmission patterns in work settings after COVID-19 spread into the community and population vaccination.Materials and MethodsFrom April to June 2022, 328 workers were enrolled in a variety of work settings. An online questionnaire was used to collect their current work industry, geographic information, vaccination of SARS-CoV-2, infection, etc. To categorize their exposure risk to COVID-19 cases from the workplace, workers were grouped into 3 different work settings according to their job nature and working environment. Non-office workers were those who normally carried out their jobs in a range of environments in an indoor or outdoor working space where close contact with the general public is frequent;Mobile workers were those who frequently move for conducting business that involves closer and more frequent contact with the general public;Office workers were those normally carry out professional duties and administrative work in an indoor working space. Breakthrough infection is defined as an infection after 14 days of full vaccination. The ethics approval number is CREC-2021.531-T.ResultsThere were 97, 151, and 80 workers in mobile, non-office, and office work groups and the infection rate were 40.2%, 40.4%, and 37.5%, respectively. 96.3% of them were full-vaccinated or get a booster shot. There was no significant difference in the breakthrough infection rate of workers in these three work settings no matter getting two or three shots of vaccine.ConclusionsWorkplace infection especially after full vaccination is not an important SARS-CoV-2 transmission pathway. [HMRF#COVID1903008, shelly@cuhk.edu.hk]

EVALUATION ON INDOOR ENVIRONMENT AND ALTERNATIVE VENTILATION METHODS IN A SCHOOL CLASSROOM IN A COLD REGION UNDER COVID-19 PANDEMIC

COVID-19 caused a global pandemic. The possibility of aerosol transmission has been pointed out as a possible route of infection, and there are reports that conventional infection control measures are insufficient to counteract aerosol transmission. Therefore, this report presents the results of an actual survey at a high school, including measurement of CO2 concentration and a questionnaire survey, and the results of an experiment to evaluate the attenuation of particle concentration by an air cleaner based on this survey.

TB-ICT: A Trustworthy Blockchain-Enabled System for Indoor Contact Tracing in Epidemic Control

Recently, as a consequence of the coronavirus disease (COVID-19) pandemic, dependence on contact tracing (CT) models has significantly increased to prevent the spread of this highly contagious virus and be prepared for the potential future ones. Since the spreading probability of the novel coronavirus in indoor environments is much higher than that of the outdoors, there is an urgent and unmet quest to develop/design efficient, autonomous, trustworthy, and secure indoor CT solutions. Despite such an urgency, this field is still in its infancy. This article addresses this gap and proposes the trustworthy blockchain-enabled system for an indoor CT (TB-ICT) framework. The TB-ICT framework is proposed to protect privacy and integrity of the underlying CT data from unauthorized access. More specifically, it is a fully distributed and innovative blockchain platform exploiting the proposed dynamic Proof-of-Work (dPoW) credit-based consensus algorithm coupled with randomized hash window (W-Hash) and dynamic Proof-of-Credit (dPoC) mechanisms to differentiate between honest and dishonest nodes. The TB-ICT not only provides a decentralization in data replication but also quantifies the node's behavior based on its underlying credit-based mechanism. For achieving a high localization performance, we capitalize on the availability of Internet of Things (IoT) indoor localization infrastructures, and develop a data-driven localization model based on bluetooth low-energy (BLE) sensor measurements. The simulation results show that the proposed TB-ICT prevents the COVID-19 from spreading by the implementation of a highly accurate CT model while improving the users' privacy and security.

Thermal Assessment of a Ventilated Double Skin Façade Component with a Set of Air Filtering Photocatalytic Slats in the Cavity

Indoor air quality is a crucial factor when evaluating habitability, especially in developed countries, where people spend most of their time indoors. This paper presents a novel double skin façade (DSF) system that combines physical and photocatalytic filtering strategies. The air purification system is made up of fixed slats that are both solar protection and air purification system. The objective of this work is to determine the thermal behaviour of the proposed system, so that its suitability for use in various environments may be assessed. This was carried out using a physical 1:1 scale model and a computational fluid dynamics (CFD) model. The maximum temperature inside the scale model cavity was 17–20 °C higher than outdoor air. Additionally, it was discovered that the airflow through the DSF would require forced ventilation. To determine the emissivity values of the photocatalytic coating, additional experimental measurements were made. The CFD model was tested for summer and winter conditions in Barcelona, Chicago, and Vancouver. The average increase in the intake air temperature was around 14.5 °C in winter and 12 °C in summer, finding that the system has its main use potential in temperate or cold areas with many hours of solar radiation.

Large-eddy simulations to define building-specific similarity relationships for natural ventilation flow rates

Natural ventilation can play an important role towards preventing the spread of airborne infections in indoor environments. However, quantifying natural ventilation flow rates is a challenging task due to significant variability in the boundary conditions that drive the flow. In the current study, we propose and validate an efficient strategy for using computational fluid dynamics to assess natural ventilation flow rates under variable conditions, considering the test case of a single-room home in a dense urban slum. The method characterizes the dimensionless ventilation rate as a function of the dimensionless ventilation Richardson number and the wind direction. First, the high-fidelity large-eddy simulation (LES) predictions are validated against full-scale ventilation rate measurements. Next, simulations with identical Richardson numbers, but varying dimensional wind speeds and temperatures, are compared to verify the proposed similarity relationship. Last, the functional form of the similarity relationship is determined based on 32 LES. Validation of the surrogate model against full-scale measurements demonstrates that the proposed strategy can efficiently inform accurate building-specific similarity relationships for natural ventilation flow rates in complex urban environments.

Airborne migration behaviour of SARS-CoV-2 coupled with varied air distribution systems in a ventilated space

Air distribution system could critically affect SARS-CoV-2 transmission in indoor space;therefore, this study aims at demonstrating numerical characteristics of SARS-CoV-2 migration with varied air distribution system configurations. Seven cases were investigated regarding three major aspects: how fast suspended particles can be removed from the ventilated space or changed into deposited particles;how much particles are attached to various object surfaces which leads to an infection by touching fomite. All cases were analyzed through computational fluid dynamics (CFD). Both different shapes (round or linear diffusers) and installation locations (ceiling or floor) of inlet and outlet diffusers were investigated. Results showed that different air distribution system would lead to different dispersion profiles of infectious particles and different deposition pattern of particles on interior surfaces. With the same air flow rate, linear-diffuser would perform better for CO2 extraction while requiring less time to remove or collide the same magnitude of suspended droplets compared to round-diffuser. However, how quickly removed or suspended droplets collide is not proportional to how less the number of total particles are remained. Two additional cases with double sized space possessing best ventilation configuration were also examined to explore potential application of the best-ventilated configuration to various spatial expansion cases.

Ventilation requirements and energy aspects: the case of hospitals

Energy building design today aims to ensure thermal comfort and indoor air quality;this concern has been increased, given the recent SARS-CoV-2 pandemic. The proposed work investigates the effect of increased natural ventilation on energy requirements, ensuring low CO2 levels and acceptable Indoor Air Quality (IAQ) in general. The case of hospitals was chosen because of the stringent IAQ requirements they raise as a result of the burdened (physical, chemical, biological) indoor environment, as well as the vulnerable health of the patients. The current energy analysis was carried out in patient wards, waiting rooms, and operating rooms. The proposed correlation between IAQ and energy is infrequent in the relevant literature, especially for the case of hospitals. Different scenarios regarding the ventilation mode are examined, including pure natural ventilation, natural ventilation combined with air cleaners, as well as mechanical ventilation. According to the results, improvement of the air quality leads to higher energy demand;this is the case of mechanical ventilation, noting that not properly designed natural ventilation techniques may lead to high energy consumption, without ensuring acceptable IAQ. Air cleaners can contribute towards better environment, potentially decreasing ventilation requirements;the issue of fresh air adequacy has to be examined though. The demonstrated methodological analysis and results can help the designer to investigate the efficiency of different ventilation modes, involving the effect of thermal envelope, geometrical and operation parameters, towards the energy requirements minimization and IAQ quality maximization.

Development of Indoor Smart Environments Leveraging the Internet of Things and Artificial Intelligence: A Case Study

The Internet of Things paradigm envisions a world where every physical object is equipped with sensing/actuation capabilities and computing power and acquires its own digital identity. These objects are referred to as "smart” and have the goal of collecting and processing information about the environment surrounding them. One of the fields of interest in IoT applications concerns the intelligent management of activities in indoor environments, even if affected by unusual restrictions due to special conditions, such as those posed by the Covid-19 pandemic. This study focuses on the development of an IoT application based on the COGITO platform for the intelligent management of meeting rooms. By processing data collected from a set of IoT devices, cameras, and cognitive microphones, the developed prototype is able to autonomously monitor and make decisions about aspects that continuously affect environmental comfort, event management, and assessment of compliance with anti-contagious regulations throughout the time the room is occupied. After a brief review of the state of the art, the chapter describes the developed application. Furthermore, it highlights the features that make meeting room environments more comfortable for users and effective in managing events such as meetings and lectures. © 2023, The Author(s), under exclusive license to Springer Nature Switzerland AG.

Stay-at-home: impact of pandemic covid-19 on the use of indoor space in Malaysian households

The prolongation of the Pandemic COVID-19 has undermined the healthcare system and negatively impacted the economy and social development on a global and regional scale. At the human settlement level, responding to the pandemic situation has altered the broad spectrum of our daily routine down to the family and individual levels. Prior to the lockdown popularly known as the Movement Control Order (MCO), which the government introduced, the public was urged to limit outdoor movements and stay at home hence, encouraging the adoption of Work From Home (WFH) for employees and Home-based Teaching and Learning (PdPR) for the academic community and school students. Other than technological readiness for online working and teaching, the new normal also prompted new challenges for households in utilizing indoor spaces at home, especially for quarantine as well as for WFH and PdPR activities. In this light, a series of household surveys using questionnaires to determine the preference and usage of indoor space among households have been conducted in 39 locations/settlements across peninsular Malaysia. A total of 504 respondents participated and fieldwork and interview processes. Findings of the study indicated a majority of respondents have to designate indoor spaces/rooms for home quarantine (58%), and the three indoor spaces, in particular, have been monitored regularly by respondents during the pandemic, namely living areas (39%), kitchen (25%) and bedroom (21%). During MCO, most of them spent 1 to 4 hours per day for PdPR (43%), and 47% of respondents have a designated learning space at home for PdPR. In summary, pandemic COVID-19 has raised awareness among households regarding the selection and usage of indoor space to conduct various activities while they have to stay at home.

Quantifying the Transmission of Outdoor Pollutants into the Indoor Environment and Vice Versa—Review of Influencing Factors, Methods, Challenges and Future Direction

Epidemiological studies have established a strong relationship between poor air quality and deteriorating human health, demanding urgent remedial measures. Specifically, indoor pollution is more critical, and outdoor pollutants significantly contribute towards indoor pollution, its strength depending on various parameters, including ventilation strategy, meteorological conditions, building design, outdoor sources, etc. This report analyses the various factors reported influencing the transmission of pollutants between the two environments. The report critically reviews various studies investigating the inter-environment variability and transmission, providing an overview of various factors and their impacts and covering both experimental and modelling studies. The review suggests that while many studies have helped to quantify the long-term personal exposure to pollutants, they have not paid special attention to the mechanism of the transmission of pollutants from the outdoor to the indoor environment and vice versa. The findings demonstrate that the proper indexing of various mechanisms and their relative strength is necessary before an effective intervention strategy can be applied in the built environment to counter the effect of pollution.

A Bibliographic Analysis of Indoor Air Quality (IAQ) in Industrial Environments

Air pollution is a major risk factor, and it still remains a global cause of death for millions of people. Indoor air quality (IAQ) plays an important role in human health as people spend most of their time in confined spaces. Many studies have recently addressed this issue, but no systematic analysis has been conducted, which is the aim of our study. We present a bibliographic analysis of articles on IAQ in industrial environments from 2010 to 2021. A total of 658 articles were collected, and 409 were used. The NVivo tool was used to analyze the collected documents both quantitatively and qualitatively. This analysis of the literature enables us to identify the most studied working environments and pollutants, the analysis tools, and the types of measurement used to provide a clear overview of the theme, which includes a comparison between the studied working environments and the state of origin of the authors. Our analysis of each working environment and the related frequently cited pollutants provides a clear approach to identifying the specific areas of focus when improving the quality of the air in a specific working environment. In addition, a research gap and future research areas have been identified in the conclusions.

Study on the Relationship between Restoration Benefit and Visual Satisfaction of LONG-PLAN’s Indoor Vertical Greenery

This study investigates the psychological restorative benefits of indoor vertical greenery and its relationship with visual satisfaction. Taking the Solar Decathlon China 2018 champion project “LONG-PLAN” as the experimental field, we conducted a questionnaire survey to evaluate the effect of indoor vertical greenery on creating a restorative environment. Then we further studied the relationship between the restorative environmental factors and visual satisfaction of indoor vertical greenery. The results show that: (1) Indoor vertical greenery has a positive impact on the subjective restoration of respondents (the average value of PRS = 4.150). (2) The three factors of “being away,” “fascination and compatibility,” and the “extent” of environmental restoration have a significant positive correlation with the visual satisfaction of indoor vertical greenery (the correlation coefficient values are 0.403, 0.627, and 0.425, respectively, p < 0.01). (3) In the stepwise regression analysis of the three factors and the visual satisfaction of indoor vertical greenery, only “fascination and compatibility” show a significant positive correlation (the regression coefficient = 0.753, p < 0.01). (4) The visual satisfaction of indoor vertical greenery has a significantly positive impact on environmental recovery (the regression coefficient = 0.459, p < 0.01). The study shows that indoor vertical greenery improves visual satisfaction and contributes to a restorative environment. In addition, the study provides further evidence of the mutual facilitation between restorative benefits and visual satisfaction.

Influence of the Heating System on the Indoor Environmental Quality—Case Study

This aim of this paper is to explore the specific indoor environmental quality factors under different heating conditions in a meeting room of an administrate building located in Kosice. In terms of thermal comfort, a system with radiant ceiling heating provides more favorable results. Low relative humidity was recorded for both heating systems, which could be due to insufficient air conditioning settings. The results of measuring CO2 concentrations were almost identical for both systems and did not exceed the recommended limit value of 1000 ppm. The increase in CO2 concentrations was mainly related to the presence of employees in the monitored room. On none of the monitoring days, whether in the case of a mechanical heating system or a radiant ceiling heating system, the average 24 h concentration of PM10 did not exceed the legally permissible limit of 50 µg/m3. The presence of selected volatile organic compounds in the room has not been demonstrated due to effective ventilation by air conditioning. The results of the evaluation were comparable and smaller fluctuations in values can be attributed to other factors, such as the presence of persons in the monitoring room or the overall heating as well as ventilation and air conditioning (HVAC) systems.