Indoor Office Building Research Articles

Assessing The Impact of Indoor Plants Towards Physical Indoor Office Building Environment in Hot and Humid Climates

Several studies have shown that plants with a variety of performance categories can improve indoor air quality (IAQ). In addition, it has positive impacts on occupants’ concentration ability, work efficiency, job satisfaction, mental health, stress reduction, and sense of well-being. However, there is few research that have focused on the impact of indoor plants towards physical indoor environment. Therefore, this study performs several experiments to examine the impacts of indoor plants on physical indoor environment in Malaysia. This study further observes the use of five different species of potted plants and its effects on the IAQ concerning the physical parameters of air temperature and relative humidity in a classroom and an office room setting environment. Moreover, this paper explores the function of plants as a natural air purifying agent and temperature regulation, as it helps to cool down the internal temperature of a building while providing areas of the building with an aesthetic element. This study involves the assessment of plant and indoor space benefit studies, as well as the description of plant varieties and characteristics. Finally, the overall findings from several experiments show significant differences in relative humidity and total target volatile organic compound (TVOC) in the room. With intervention, it can be concluded that the inclusion of potted plants in a room have improved all parameters measured compared with that in normal condition. For future works, it is proposed that further study is done on the form of species, including the importance of understanding the need for positioning the potted plants in indoor environments.

Millimeter Wave and Sub-Terahertz Spatial Statistical Channel Model for an Indoor Office Building

Millimeter-wave (mmWave) and sub-Terahertz (THz) frequencies are expected to play a vital role in 6G wireless systems and beyond due to the vast available bandwidth of many tens of GHz. This paper presents an indoor 3-D spatial statistical channel model for mmWave and sub-THz frequencies based on extensive radio propagation measurements at 28 and 140 GHz conducted in an indoor office environment from 2014 to 2020. Omnidirectional and directional path loss models and channel statistics such as the number of time clusters, cluster delays, and cluster powers were derived from over 15,000 measured power delay profiles. The resulting channel statistics show that the number of time clusters follows a Poisson distribution and the number of subpaths within each cluster follows a composite exponential distribution for both LOS and NLOS environments at 28 and 140 GHz. This paper proposes a unified indoor statistical channel model for mmWave and sub-Terahertz frequencies following the mathematical framework of the previous outdoor NYUSIM channel models. A corresponding indoor channel simulator is developed, which can recreate 3-D omnidirectional, directional, and multiple input multiple output (MIMO) channels for arbitrary mmWave and sub-THz carrier frequency up to 150 GHz, signal bandwidth, and antenna beamwidth. The presented statistical channel model and simulator will guide future air-interface, beamforming, and transceiver designs for 6G and beyond.

A Simple Positioning System for Large-Scale Indoor Patrol Inspection Using Foot-Mounted INS, QR Code Control Points, and Smartphone

A reliable and practical personnel positioning system is necessary for large-scale indoor patrol inspection. In this study, we designed a personnel positioning system that entails the implementation of a foot-mounted inertial module, a smartphone, and pre-determined sparse QR code points. Foot-mounted inertial navigation system (Foot-INS) is self-contained system that send real-time dead-reckoning positions to a smartphone via a built-in Bluetooth module. When the inspector arrives at a planned control point area marked by the QR code, the smartphone actively scans the QR code and obtains the three-dimensional (3D) coordinates of the control point. Then, a newly developed data fusion algorithm performs real-time and post-processing fusion of the relative foot position and 3D QR code control point coordinate data. The proposed algorithm was implemented on an Android smartphone and was evaluated by extensive experiments in an indoor office building and an outdoor open-sky area. The experimental results confirmed the effectiveness and feasibility of the proposed personnel positioning system. The designed system was proven to be decent, robust, and not susceptible to environmental changes. It is also low-cost, has low power consumption, is easy to operate, and is compatible with common smartphones. Moreover, the proposed personnel positioning system provides a practical application pattern of the Foot-INS.

WiFi and Vision-Integrated Fingerprint for Smartphone-Based Self-Localization in Public Indoor Scenes

Smartphone-based indoor localization systems are increasingly needed in various types of applications. This article proposes a novel WiFi and vision-integrated fingerprint (Wi-Vi fingerprint) for accurate and robust indoor localization. The method consists of two steps of fingerprint mapping and fingerprint localization. In the mapping step, the Wi-Vi fingerprints for all the sampling sites are computed by using EXIT signs as landmarks. In the localization step, a multiscale localization strategy is proposed, which includes coarse localization from weighted access points (WAPs)-based WiFi matching, the Gaussian weighted KNN (GW-KNN)-based image-level localization from holistic visual features, and finally, the metric localization for refinement. The proposed method has been tested in an indoor office building of 12 000 m2 and a mega-mall of 7200 m2 with different types of smartphones. The experimental results demonstrate that the proposed method can achieve 95% and 98% site recognition rates from image-level localization. The final localization errors after metric localization are less than a half meter on average.

Study on the Influence of Air Tightness of the Building Envelope on Indoor Particle Concentration

In order to grasp the building palisade structure tightness of indoor particulate matter mass concentration based on the particle penetration mechanism and settlement characteristics, this article analyzes the measurements of two different types of building air tightness of a Shenyang university office building in terms of indoor and outdoor particulate matter mass concentration levels from 2016-1-09 to 1-22, 2016-7-18 to 8-03, and 2017-2-28 to 3-13. The building outside the closed window that had no indoor source condition, the indoor office building and outdoor particle mass concentration, and the aperture size and shape of the envelope were analyzed to carry on the numerical simulation research by Fluent software, which was then analyzed; the results reveal that the measuring point of the I/O ratio is less than point B of the I/O ratio, measurement points of A linear regression fitting degree is lower than the fit of the measuring point B, and the causes for the measuring point A tightness (level 8) is superior to the measuring point B (level 4). When the gap height h is greater than 0.5 mm, the penetration rate of particles within the range of 0.25–2.5 μm particle size is close to 1. In different gap depths, the penetration rate of particles within the range of 0.1–1 μm particle size was close to 1. In diverse pressure difference, the 0.25–2.5 μm particles within the scope of penetration rate P is close to 1, the gap on both sides of the differential value ΔP; the greater the particle, the higher penetration rate. The larger the right-angle number of gap n, the lower the penetration rate of particles. The L-shaped gap and U-shaped gap have significantly better barrier effects in larger and smaller particles than the rectangular gap. The research results in this paper can help people understand and effectively control the influence of outdoor particles on the indoor air quality and provide reference data for the prediction of indoor particle mass concentration in buildings, which has theoretical basis and practical significance.

Emerging Insights into the Occupational Mycobiome.

The evolution of molecular-based methods over the last two decades has provided new approaches to identify and characterize fungal communities or "mycobiomes" at resolutions previously not possible using traditional hazard identification methods. The recent focus on fungal community assemblages within indoor environments has provided renewed insight into overlooked sources of fungal exposure. In occupational studies, internal transcribed spacer (ITS) region sequencing has recently been utilized in a variety of environments ranging from indoor office buildings to agricultural commodity and harvesting operations. Fungal communities identified in occupational environments have been primarily placed in the phylum Ascomycota and included classes typically identified using traditional fungal exposure methods such as the Eurotiomycetes, Dothideomycetes, Sordariomycetes, and Saccharomycetes. The phylum Basidiomycota has also been reported to be more prevalent than previously estimated and ITS region sequences have been primarily derived from the classes Agaricomycetes and Ustilaginomycetes. These studies have also resolved sequences placed in the Basidiomycota classes Tremellomycetes and Exobasidiomycetes that include environmental and endogenous yeast species. These collective datasets have shown that occupational fungal exposures include a much broader diversity of fungi than once thought. Although the clinical implications for occupational allergy are an emerging field of research, establishing the mycobiome in occupational environments will be critical for future studies to determine the complete spectrum of worker exposures to fungal bioaerosols and their impact on worker health.

Interior shadings for office indoor visual comfort in humid climate region

As part of the fenestration system, the interior shadings have also a role to control the indoor environment to maintain indoor visual comfort. As the occupants have personal access to control these, their control behavior then, might enhance or even worsen indoor comfort performance. The controlling behavior might not only influence indoor comfort performance but can also indicate the success or failure of interior shading as a control device element. This paper is intended to report control behavior patterns, as represented by the variety of the slats’ openings of two types of interior shading i.e. Venetian and Vertical blinds and to analyze these on the concurrent impacts to indoor office building’s indoor illuminance and luminance distribution. The purpose of this research is to figure out the shading control patterns as well as to examine the effectiveness of these two types of interior shadings to control indoor visual environment. This study is a quantitative research using experimentation on the slats’ opening of two types of shadings at two identical office rooms. The research results suggested that both types of blinds seem unsuitable for gaining proper illumination values at work planes in humid tropics area. However, these shadings demonstrate good performance for luminance distribution except for that of the closed Venetian blinds.

Modelling and performance analysis of a silicon PV module

Significant effect and progress have been made by manufacturers and researchers to understand the performance and modelling concept of photovoltaic (PV) modules under various conditions such as wind, dust, and snow, which are often harsh and may lead to the degradation of PV modules. This paper presents a study on the performance of an 85 W monocrystalline photovoltaic module under different conditions, with measurements being taken under indoor and outdoor conditions. To obtain maximum irradiation under outdoor conditions, the module was inclined at an angle of 25° facing the southern direction (UK). To investigate the I-V characteristic of the PV module, a single diode electrical equivalent model has been developed using MATLAB-Simulink, and the measured results are discussed together with the simulation results. The measured results have shown that the module is capable of generating 17.75 W/m2 with an efficiency of 7% and 138 W/m2 with an efficiency of 8% from indoor office building and outdoor conditions, respectively, in UK during summer time. This research work makes a significant contribution to photovoltaic researchers to identify the suitable applications such as embedded devices or body-worn sensors for use both in indoor and outdoor conditions.

Characteristics of the Concentration Change of the Particulate Matter in the Indoor and Outdoor Existing Public Office Buildings

In order to clarify the influence of outdoor inhalable particulate matter on the interior of existing public office buildings in Cold area, this paper uses the method of weight method and instantaneous detection to measure the indoor and outdoor inhalable particulate matter concentration of two existing office buildings in Shenyang in summer. The changes of daily average, instantaneous concentration and I/O ratio of PM2.5 and PM10 in the indoor and outdoor are analyzed, and the influence of outdoor particulate matter on the concentration of indoor and outdoor inhalable particulate matter in two buildings was analyzed by analyzing the correlation of indoor and outdoor concentration change and regression. This paper provides a reference for the study of the different airtight buildings on the barrier properties of outdoor inhalable particulate matter and the improvement of the indoor environment quality.

Seasonal fate and gas/particle partitioning of semi-volatile organic compounds in indoor and outdoor air

Fifty-eight semi-volatile organic compounds (SVOCs) were investigated simultaneously in three indoor (apartment, nursery and office building) and one outdoor environment in the centre of Paris (France). All of these compounds except tetrabromobisphenol A were quantified in the gaseous and particulate phases in all three environments, and at a frequency of 100% for the predominant compounds of each SVOC class. Phthalic acid esters (PAEs) were the most abundant group (di-iso-butyl phthalate: 29–661 ng m−3, diethyl phthalate: 15–542 ng m−3), followed by 4-nonylphenol (1.4–81 ng m−3), parabens (methylparaben: 0.03–2.5 ng m−3), hexachlorobenzene (HCB) (0.002–0.26 ng m−3) and pentachlorobenzene (PeCB) (0.001–0.23 ng m−3). Polycyclic aromatic hydrocarbons (as ∑8PAHs) ranged from 0.17 to 5.40 ng m−3, polychlorinated biphenyls (as ∑7PCBi) from 0.06 to 4.70 ng.m3 and polybromodiphenyl ethers (as ∑8PBDEs) from 0.002 to 0.40 ng m−3. For most pollutants, significantly higher concentrations were observed in the nursery compared to the apartment and office. Overall, the indoor air concentrations were up to ten times higher than outdoor air concentrations. Seasonal variations were observed for PAEs, PCBs and PAHs. SVOCs were predominantly identified in the gaseous phase (>90%), except for some high-molecular-weight PAEs, PAHs and PCBs.

A Hybrid Positioning Scheme Exploiting Sensors and RSS of Wi-Fi Signals

As interests and demands for indoor positioning have recently increased, a positioning scheme utilizing the smartphone equipped with various sensors like an acceleration sensor and a geomagnetic sensor has been expected as a high potential and practical candidate for indoor positioning purpose. The acceleration sensor and the geomagnetic sensor are used for the estimation of travelled distance and the direction of movement of pedestrians, respectively. Although it provides very accurate positioning performance, the positioning scheme based only sensors tends to be affected by indoor environments like magnetic field of general indoor office building. In addition, the positioning error is apt to be accumulated as the travelled distance is increased. In this paper, therefore, a new positioning scheme is proposed to compensate the conventional positioning technology and to enhance the positioning performance. The proposed scheme consists with positioning based sensors, multi-lateration and WLAN-ID based on received signal strength (RSS) of Wi-Fi signals. The proposed scheme is evaluated with experiments at general building in university and the performance of the proposed scheme is superior to the conventional schemes such as a positioning scheme with only sensors and a positioning scheme based on RSS of Wi-Fi signals only.

Distributed Bayesian Inference for Consistent Labeling of Tracked Objects in Nonoverlapping Camera Networks

One of the fundamental requirements for visual surveillance using nonoverlapping camera networks is the correct labeling of tracked objects on each camera in a consistent way, in the sense that the observations of the same object at different cameras should be assigned with the same label. In this paper, we formulate this task as a Bayesian inference problem and propose a distributed inference framework in which the posterior distribution of labeling variable corresponding to each observation is calculated based solely on local information processing on each camera and mutual information exchanging between neighboring cameras. In our framework, the number of objects presenting in the monitored region does not need to be specified beforehand. Instead, it can be determined automatically on the fly. In addition, we make no assumption about the appearance distribution of a single object, but use “similarity” scores between appearance pairs as appearance likelihood for inference. To cope with the problem of missing detection, we consider an enlarged neighborhood of each camera during inference and use a mixture model to describe the higher order spatiotemporal constraints. Finally, we demonstrate the effectiveness of our method through experiments on an indoor office building dataset and an outdoor campus garden dataset.

Clustering and fault tolerance for target tracking using wireless sensor networks

Using wireless sensor networks to track a moving object provided a practical solution to a wide variety of applications including, for example, wild life, military operations, intruder tracking and monitoring in indoor office buildings. While much work has been done in this area, failures are not considered in most of the existing solutions. However, failures have to be handled carefully in target tracking applications because of their unpredictable and dynamic nature of communication, such as sensor energy depletion, severe environment conditions, unstable communication links and malicious attacks. Traditional approaches of fault tolerance are not well suited to address these new challenges. Therefore the authors propose a novel fault-tolerant target tracking (FTTT) protocol based on clustering. Also, the results of an investigation in terms of performance overheads and scalable nature of the FTTT protocol via comparative simulations with LEACH are discussed. Overall, in all the cases, FTTT consumes at least 25% less energy than LEACH.

Indoor biological contaminants and symptoms of sick building syndrome in office buildings in Mauritius

This study was carried out to investigate possible relationship between bio-contaminants and symptoms of sick building syndrome among office workers in Mauritius. Viable microbial colonies were collected using a Casella slit sampler in 23 selected indoor office buildings. A questionnaire survey as well as a walk through investigation was undertaken. Physico-chemical measurements were also monitored in the selected offices. Results of this study showed that number of indoor bacterial bioaerosol concentrations ranged between 3 and 1110 CFU/m 3 while fungal counts were 0-196 CFU/m 3 . However, most of the buildings showed absence of dust mites. In conclusions fungal contamination was found to be associated with the onset of sick building syndrome symptoms among workers in office buildings in Mauritius.