Investigating path loss characteristics of UWB signals in vacancy indoor environment based on time-domain technique

The path loss analysis model based on 5 rays in vacancy indoor environment is proposed. The relationship between multipath overlapping and the path loss is analyzed mathematically. Time-domain technique is introduced to compute reflection coefficient in a very short time interval. A 5 rays path loss calculation method, which is satisfactory accurate, is developed. 5 typical environments are involved to analyze and generalize the common path loss characteristics in vacancy indoor environment. The simulation result shows that the path loss can be characterized as 3 zones with different path loss exponent as distance between transmitter and receiver increasing.

Specific Enthalpy Based Heat Stress Index for Indoor Environments without Radiation Effect

Over 100 human thermal indices have been developed to predict the combined thermal impact on the body.In principle,these indices based on energy thermal budget equations should not only be the most complex but also be the most accurate.However,the simple indices based on algebraic or statistical models[e.g.,the wet-bulb globe temperature(WBGT)]continue to be the most popular.A new heat stress index,the enthalpy dry-bulb temperature(EnD)for indoor environments is developed and validated in this study.The EnD index is unique in that it uses the air specific enthalpy,not the wet-bulb temperature,to measure the latent heat transfer from the skin to the surrounding environment.Theoretically,the EnD index can be treated as the equivalent temperature based on the convective heat transfer coefficient h_(c).Comparison is made between the EnD index and the widely used WBGT index based on the experimental data taken from three independent studies available in the scientific literature.The results show that the EnD index can reduce the overestimation of the dry-bulb air temperature and thus reduce heat stress in most cases,especially for hot and humid environments.It can be concluded that the EnD index has the potential to replace the WBGT index as the standard heat stress index in the future.

Hardware Implementation of STM32 Microcontroller-Based Indoor Environment Monitoring System

Microcontroller is widely used in the intelligent life of modern society. Intelligent development based on Microcontroller to solve the actual needs of people’s life, work, study and other fields is the core of Microcontroller application. Therefore, it is a task for researchers to understand the structure and performance of microcontroller, develop software, and be familiar with the method and process of intelligent development based on microcontroller. And with that in mind, this paper designs and produces a physical hardware system for indoor environment detection based on STM32 microcontroller. The system can detect the light intensity, temperature and humidity, and CO gas concentration in the indoor environment;and the data is integrated and processed by the STM32 microcontroller to display the current parameter values of each quantity in the indoor environment on a 3.5-inch resistive screen;at the same time, the PC can also log in to the OneNET cloud platform through the web page, and display the light intensity, temperature and humidity, and CO gas concentration values in the indoor environment in real time in the device created by OneNET for real-time viewing. The system can also display the light intensity, temperature and humidity, and CO gas concentration values in the indoor environment in real time. The hardware system has been tested and tested to achieve its function.

Indoor Environment Quality Monitoring and Evaluation System Based on LoRa Communication

Indoor environmental quality has always been the focus of people’s long-term attention. How to monitor the indoor environmental level conveniently and accurately is a problem that people pay attention to now. After research, an indoor environment level monitoring system based on LoRa communication is designed. The system is mainly divided into two parts, the detection node, and the monitoring terminal. Temperature, humidity, light intensity, noise, formal-dehyde, and carbon dioxide are detected through the node with STM32F103ZET6 microcontroller as the controller;the data is sent to the monitoring terminal for display through LoRa communication. At the same time, the T-S fuzzy neural network (TSFNN) is improved by the particle swarm optimization (PSO) algorithm to classify the indoor environment quality level. Experimental test: the total error of the improved TSFNN model test set is reduced by 8.6007. The system can monitor the indoor environment level objectively and reliably, and has high practical value.

Influence of the 60 Hz Magnetic Field on the Airborne Microbial Distribution of Indoor Environments

The aim of this work was to analyze the effect of the magnetic field generated by the household appliances on the airborne microbial surrounding these equipment located on indoor environments with particular interest in the environmental fungi.A simultaneous environmental study was carried out in locals of three different geographical places of Havana,Cuba,which have televisions,computers and an electric generator.The air samples were made by a sedimentation method using Malt Extract Agar.The concentration of total aerobic mesophilic as well as fungi and yeasts were determined in rainy and little rainy seasons by applying as factors:exposure time of dishes(5 to 60 min)and distance to the wall(0 and 1 m)at a height of 1 m above the floor.The predominant fungal genera were Cladosporium,Penicillium and Aspergillus.In the dishes that were placed at 0 and 0.5 m from the emitting sources were observed that some bacteria colonies formed inhibition halos,a great diversity of filamentous fungi and an increase in the mycelium pigmentation as well as the pigments excretion.In the rainy season,the highest amounts of fungi were obtained in all samples.In the little rain season the count of the Gram-negative bacilli increased three times the Gram-positive cocci.

Energy consumption,indoor environmental quality,and benchmark for office buildings in Hainan Province of China

With rapid economy growth,building energy consumption in China has been gradually increased.The energy consumption and indoor environmental quality of 51 office buildings in Hainan Province,a hot and humid area,were studied through collection of verified data in site visits and field tests.The result revealed that,electricity accounted for 99.79% of the total energy consumption,natural gas 0.17%,and diesel 0.04%.The air conditioning dominated the energy use with a share of 43.18%,equipment in the particular areas 26.90%,equipment in the office rooms 11.95%,lighting system 8.67%,general service system 7.57%,and miscellaneous items 1.73%.Statistical method including six indicators obtained the energy consumption benchmark with upper limit of 98.31 kW-h/m2 and lower limit of 55.26 kW-h/m2.According to ASHRAE standard(comfortable standard) and GB/T 18883-2002(acceptable standard),the indoor environmental quality of 51 sampled office buildings was classified into three ranks:good,normal and bad.With benchmark of building energy consumption combined with indoor environmental quality,it was found that only 3.92% of sampled buildings can be identified as the best performance buildings with low energy consumption and advanced indoor environmental quality,and the buildings classified into normal level accounted for the maximum ratio.

Subjective evaluation of indoor environmental quality of underground shopping malls in central district of Chongqing,China

Good indoor environmental quality enhances occupant health,comfort and productivity. In order to know the status of indoor environmental quality of underground shopping malls,five large underground shopping malls in five central districts of Chongqing,China,were surveyed. 2 411 questionnaires were distributed,and 98.5% of them were returned. From the results of questionnaire survey,the following conclusions were obtained:(1) in the five underground shopping malls surveyed,only shopping mall D in Nan'an district accords with the ASHRAE standard for good indoor air quality; (2) odors and sick building syndrome (SBS) symptoms are widespread in the underground shopping malls. The SBS occurrence rates for women and salespersons are higher than those of men and customers,respectively; (3) in the evaluation of the indoor environment,the indoor air quality dissatisfaction rate is the highest,followed by the thermal environment; and (4) women and salespersons generally have higher rates of dissatisfaction with the indoor environmental quality of underground shopping malls than men and customers,respectively.

Application of statistical analysis of sample size:How many occupant responses are required for an indoor environmental quality(IEQ)field study

Determining required sample size is one of the critical pathways to reproducible,reliable and robust results in human-related studies.This paper aims to answer a fundamental but often overlooked question:what sample size is required in surveys of occupant responses to indoor environmental quality(IEQ).The statistical models are introduced in order to promote determining required sample size for various types of data analysis methods commonly used in IEQ field studies.The Monte Carlo simulations are performed to verify the statistical methods and to illustrate the impact of sample size on the study accuracy and reliability.Several examples are presented to illustrate how to determine the value of the parameters in the statistical models based on previous similar research or existing databases.The required sample size including“worst”and“optimal”cases in each condition is obtained by this method and references.It is indicated that 385 is a“worst case”sample size to be adequate for a subgroup analysis,while if the researcher has an estimate of the study design and outcome,the“optimal case”sample size can potentially be reduced.When the required sample size is not achievable,the uncertainty in the result can properly interpret via a confidence interval.It is hoped that this paper would fill in the gap between statistical analysis of sample size and IEQ field research,and it can provide a useful reference for researchers when planning their own studies.

Digital twin for healthy indoor environment:A vision for the post-pandemic era

Indoor environment has significant impacts on human health as people spend 90%of their time indoors.The COVID-19 pandemic and the increased public health awareness have further elevated the urgency for cultivating and maintaining a healthy indoor environment.The advancement in emerging digital twin technologies including building information modeling(BIM),Internet of Things(IoT),data analytics,and smart control have led to new opportunities for building design and operation.Despite the numerous studies on developing methods for creating digital twins and enabling new functionalities and services in smart building management,very few have focused on the health of indoor environment.There is a critical need for understanding and envisaging how digital twin paradigms can be geared towards healthy indoor environment.Therefore,this study reviews the techniques for developing digital twins and discusses how the techniques can be customized to contribute to public health.Specifically,the current applications of BIM,IoT sensing,data analytics,and smart building control technologies for building digital twins are reviewed,and the knowledge gaps and limitations are discussed to guide future research for improving environmental and occupant health.Moreover,this paper elaborates a vision for future research on integrated digital twins for a healthy indoor environment with special considerations of the above four emerging techniques and issues.This review contributes to the body of knowledge by advocating for the consideration of health in digital twin modeling and smart building services and presenting the research roadmap for digital twin-enabled healthy indoor environment.

Research progress on indoor environment of mushroom factory

Mushroom factory is an emerging production mode that is relied on facility and equipment by creating a suitable,steady,and uniform growing environment to accommodate the demand of edible fungus at each stage of growth.Therefore,an optimal range of key environmental factors(temperature,humidity,light,and CO_(2) concentrations)in mushroom facilities is crucial to achieving satisfactory production rates.This research aimed to provide an overview of recent progress on indoor environmental studies of mushroom cultivation facilities from three perspectives,1)the development of environmental monitoring and controlling systems;2)the application of computer modelling in addressing indoor environmental issues;3)the refinement of mushroom facility design,including structure and ventilation scheme.With the aid of cutting-edge technologies,accomplishments have been made in developing smart farming systems that facilitate real-time recording of environmental parameters and automatic regulation of equipment,which helps the establishment of growth model for specific mushroom species.Computational Fluid Dynamics(CFD)modelling has been adopted by researchers to investigate indoor airflow patterns and assess the distribution of critical environmental parameters.Studies have been conducted to modify the design of mushroom facility to improve the performance in structural stability,ventilation efficiency,and internal environmental condition.However,some existing problems still need further investigations,such as the lack of design guidelines,energy-saving strategies,and Artificial Intelligent(AI)quality control.Therefore,this overview was expected to provide constructive insights for future studies in addition to references of previous studies.

Machine Learning and Deep Learning Methods for Enhancing Building Energy Efficiency and Indoor Environmental Quality – A Review

The built environment sector is responsible for almost one-third of the world’s final energy consumption. Hence, seeking plausible solutions to minimise building energy demands and mitigate adverse environmental impacts is necessary. Artificial intelligence (AI) techniques such as machine and deep learning have been increasingly and successfully applied to develop solutions for the built environment. This review provided a critical summary of the existing literature on the machine and deep learning methods for the built environment over the past decade, with special reference to holistic approaches. Different AI-based techniques employed to resolve interconnected problems related to heating, ventilation and air conditioning (HVAC) systems and enhance building performances were reviewed, including energy forecasting and management, indoor air quality and occupancy comfort/satisfaction prediction, occupancy detection and recognition, and fault detection and diagnosis. The present study explored existing AI-based techniques focusing on the framework, methodology, and performance. The literature highlighted that selecting the most suitable machine learning and deep learning model for solving a problem could be challenging. The recent explosive growth experienced by the research area has led to hundreds of machine learning algorithms being applied to building performance-related studies. The literature showed that existing research studies considered a wide range of scope/scales (from an HVAC component to urban areas) and time scales (minute to year). This makes it difficult to find an optimal algorithm for a specific task or case. The studies also employed a wide range of evaluation metrics, adding to the challenge. Further developments and more specific guidelines are required for the built environment field to encourage best practices in evaluating and selecting models. The literature also showed that while machine and deep learning had been successfully applied in building energy efficiency research, most of the studies are still at the experimental or testing stage, and there are limited studies which implemented machine and deep learning strategies in actual buildings and conducted the post-occupancy evaluation.

The integration model of objective and subjective data of residential indoor environment quality in Northeast China based on structural equation modeling

Currently the indoor environment quality is described or evaluated mainly by the subjective or objective data.However,research increasingly has demonstrated that objective and subjective data both had some weaknesses to characterize the indoor environment quality,and they can compensate for each other's relative weaknesses.Hence,this study aims to develop an integration model to allow indoor subjective and objective data to be combined based on the structural equation modeling approach,using the Northeast China residential indoor environmental survey data.The results indicated that the integration model had a good fit for the survey data,and the model validity was confirmed.Moreover,in contrast to the subjective data(R^(2)=0.363)and objective data(R^(2)=0.239),the integrated data(R^(2)=0.553)improved the explanatory power on the satisfaction with the overall indoor environment.Furthermore,this integration model demonstrated that indoor subjective data assigned more weights to the integrated data than the corresponding objective data.The association strength of thermal environment and indoor air quality(0.43 or 0.47)was the strongest among the interactions of thermal,air quality,acoustic,and lighting environments.Consequently,the main contribution of this paper was that it provided a comprehensive model to accomplish the integration of indoor environmental subjective and objective data,promoting the ability to describe and assess the indoor environment quality.

Improved indoor environment through optimised ventilator and furniture positioning:A case of slum rehabilitation housing,Mumbai,India

This study optimized the ventilator and furniture location of a tenement unit in a low-income urban habitat to obtain maximum experiential indoor environmental quality(e-IEQ)over the breathing zone.Hypothetical interior layouts using a combination of the two design parameters of ventilator location and bed position were generated for optimizing the design layout.This layout could promote maximum indoor airflow and minimum indoor air temperature and contaminant concentration.In this study,an improved indoor environment is hypothesized to be attainable through improved natural ventilation and thermal performance in the occupied zones.A sequential methodology involving“parametric design modeling ecomputational simulationemultiobjective optimizationemulticriteria decision making”-based framework was selected.Results exhibited that the currently designed tenement unit had a poor indoor environment,whereas the hypothesized iterated layout“optimized design layout,scenario 3(ODL 3)”derived from the optimization and decision-making algorithm performed effectively in providing e-IEQ.An increase in experiential indoor air velocity by 0.2 m/s and a decrease in temperature by 2C were observed over the monitoring point in the ODL 3 considering the existing scenario.Therefore,this study can find a way toward the development of sustainable habitat design guidelines under upcoming slum redevelopment policies across the nation.

Indoor environmental quality(IEQ)assessment of Nigerian university libraries:A pilot study

An indoor environmental quality(IEQ)assessment of academic libraries in Nigeria was conducted through ob-jective measurements.The selected university libraries were Abubakar Gimba Library;Awwal Ibrahim Library;and Ibrahim Badamosi Babangida Library Complex.The libraries were evaluated under operating conditions and during their peak usage periods.Measurements of the main descriptors of good IEQ,including the acoustical,visual,and thermal comfort conditions were performed using portable IEQ meters.The methodology employed for the assessment of these IEQ descriptors followed prescriptions of international standards ASHRAE standard 55 and ISO 7730.To determine the time of the day in which the library buildings can achieve optimum IEQ,measurements were taken in the morning and afternoon.The results obtained were compared with reference values found in the international Standard CIBSE Guide A for adequate IEQ compliance of academic libraries.The findings of this study are expected to help in improving the IEQ of academic libraries in Nigeria and other parts of the world.

Indoor environment of nearly zero energy residential buildings with conventional air conditioning in hot-summer and cold-winter zone

According to the few researches on Nearly zero energy residential buildings(NZERB)in hot-summer and cold-winter zone,although it could reduce the cooling load of buildings due to its high thermal insulation and air tightness,it still needed for certain cooling in summer.This paper studied indoor environment of NZERB un-der three kinds of air-conditioners(split-type air-conditioner,multi-line air-conditioner and ceiling radiant air-conditioner).Firstly,a simulation model of NZERB was established based on Nanjing,a typical city in hot-summer and cold-winter zone.Secondly,variation of indoor air temperature and building load characteristics with outdoor air temperature were studied.Thirdly,indoor environment and energy consumption under three selected con-ventional air-conditioners in summer were simulated.Finally,the discussion was given,and an air-conditioner combining with convective and radiant cooling were proposed.The results indicated that the air-conditioner needed to be turned on in NZERB in hot-summer and cold-winter zone due to the room air temperature in off-air condition ranged from 32℃to 36℃,which was higher than designed indoor environment temperature in sum-mer,but the indoor environment of NZERB under three selected conventional air-conditioners could not meet the requirements of energy saving and comfort at the same time,and a proposed convective-radiant air-conditioner could be fast,stable,and energy saving.The findings can provide a reference for conducting active technology in NZERB.

Housing characteristics and indoor environment in relation to children's asthma, allergic diseases and pneumonia in Urumqi, China

In order to evaluate the prevalence of childhood asthma,allergic diseases and pneumonia in Urumqi City,China,as well as its associations with housing and home characteristics,a cross-sectional study was performed in 4618 children(81.7%response rate,average age 4.7±0.9 year,boys accounting for 53.7%).Questions on children’s asthma and allergic diseases were from the International Study on Asthma and Allergies in Childhood(ISAAC)and were integrated with questions on the home environment from the Dampness in Buildings and Health(DBH)study,slightly modified to account for Chinese building characteristics and life habits.The prevalences of physician diagnosed asthma,allergic rhinitis(AR)and pneumonia were 3.6%,8.7%and 40.9%,respectively.One fourth of children reported wheezing and more than 40%AR symptoms in the last 12 months.Controlling for confounding factors,positive associations were found for home mold/dampness and wheezing(adjusted odds ratio,aOR 1.33,95%CI 1.07 1.66),AR symptoms(1.34,1.09 1.64)last 12 months and physician diagnosed pneumonia(1.33,1.09 1.62).Floor material by wood,PVC or carpeting;and walls by wallpaper,painting or wood material,were positively associated with AR symptoms.Home environmental tobacco smoke(ETS)was positively associated with wheezing(1.23,1.04 1.46)and pneumonia(1.25,1.07 1.45).In conclusion,there was a relatively high prevalence of asthmatic and AR symptoms and diagnosed pneumonia in preschool children in Urumqi.Home signs of mold growth or dampness,windowpane condensation,as well as ETS and interior surface materials emitting chemicals were risk factors for allergic symptoms and pneumonia.

Indoor Environment Control Effect Based on Multi-Impeller Air Conditioner

Air conditioner is the key air supply device to improve the indoor air heat transfer cycle and thermal environment. In this paper, according to the similarity theory, six kinds of the multi-impeller air conditioners(MIAC) with different numbers of axial-flow impeller are first proposed based on air conditioners with cross-flow fan(CFAC). The effects of different multi-impeller air supply modes on the indoor airflow field and temperature field are investigated by using the numerical simulation method. The validity of the computational model and method is verified by comparing the experimental measurements and numerical results. Compared with other air supply modes, the air supply distance is relatively far and the indoor environment is also improved obviously when the six-impeller air conditioner(SIAC) is used. The independent multiple impellers and outlets of SIAC make the mutual interference between the outlet airflow less, which effectively reduces the friction between the airflow and the degree of loss along the way and makes the cold and heat exchange of the whole indoor space more sufficient. The indoor thermal environment is also analyzed by using the PMV-PPD method and prototype experiment. Under the working condition of no wind, the indoor thermal comfort of human body with SIAC is better than that of CFAC. Especially in the horizontal plane of 0.6 m above the human foot, the indoor thermal environment improvement effect is the most obvious. Simultaneously, the temperature difference along the indoor height direction with the SIAC is only 1.7℃, which is 70% lower than that of the CFAC. The blowing angle between the left and right side of the SIAC is 106°, which is 31% higher than that of the CFAC. Therefore, the overall thermal comfort of the six-impeller mode is better, and the control effect of indoor environment is satisfactory.

Behavior of the Cultivable Airborne Mycobiota in air-conditioned environments of three Havanan archives, Cuba

High concentrations of environmental fungi in the archives repositories are dangerous for the documents preserved in those places and for the workers'health.The aims of this work were to evaluate the behavior of the fungal concentration and diversity in the indoor air of repositories of 3 archives located in Havana,Cuba,and to demonstrate the potential risk that these taxa represent for the documentary heritage preserved in these institutions.The indoor and outdoor environments were sampled with a biocollector.From the I/O ratios,it was evident that two of the studied archives were not contaminated,while one of them did show contamination despite having temperature and relative humidity values very similar to the other two.Aspergillus,Penicillium and Cladosporium were the predominant genera in the indoor environments.New finds for archival environments were the genera Harposporium and Scolecobasidium.The principal species classified ecologically as abundant were C.cladosporioides and P.citrinum.They are known as opportunistic pathogenic fungi.All the analyzed taxa excreted acids,the most of them degraded cellulose,starch and gelatin while about 48%excreted different pigments.But 33%of them showed the highest biodeteriogenic potential,evidencing that they are the most dangerous for the documentary collections.

基于迁移学习的动态环境室内定位方法研究

随着智能家居应用的不断深化,基于Wi-Fi信号的室内定位技术也受到了广泛关注。在实际应用中,大多数室内定位算法采集得到的训练数据和测试数据通常并非来自于同一理想环境,各种环境条件变化以及信号漂移导致采集得到的训练数据和测试数据间的概率分布不同。传统定位模型在面对不同分布的训练数据和测试数据时无法保证具有良好的定位精度,常出现算法定位精度大幅降低,甚至算法不可用等问题。面对这一难点,迁移学习中的域适应方法作为一种可以有效解决训练样本和测试样本概率分布不一致的学习问题被广泛应用于室内定位领域。文中结合域适应学习和机器学习算法,提出了一种基于特征迁移的室内定位算法(Transfer Learning Location AlgorithmBased on Global and Local Metrics Adaptation,TL-GLMA)。TL-GLMA在定位阶段通过特征迁移方式将两域原始数据映射至高维空间,从而在最小化两域数据的分布差异的同时保留两域数据内部的局部几何属性,并利用映射后的独立同分布数据训练分类器,从而实现目标定位。实验结果表明,TL-GLMA能够有效减少环境变化带来的干扰,提升定位精度。