Simulated Indoor Environment Research Articles

Deep Neural Network-Based Scene Graph Generation for 3D Simulated Indoor Environments

Deep Neural Network-Based Scene Graph Generation for 3D Simulated Indoor Environments

Recovery in sensory-enriched break environments: integrating vision, sound and scent into simulated indoor and outdoor environments

To deal with stress and exhaustion at work, personal resources need to be replenished during breaks. The aim of this laboratory study (n = 122 students) was to test the restorative potential of sensory-enriched break environments (SEBEs) in between-subjects with repeated measures design, focusing on the type of the environment (natural outdoor vs. built indoor environment) and sensory input (no sensory input vs. audiovisual input vs. audiovisual and olfactory input). Analyses showed that SEBEs simulating either a natural or a lounge environment were perceived as more pleasant and restorative (fascination/being away) than a standard break room, which in turn facilitated the recovery of personal resources (mood, fatigue, arousal). Moreover, adding a congruent scent to an audiovisual simulation indirectly facilitated the recovery of personal resources via greater scent pleasantness and higher fascination and being away. The current study shows the opportunities for sensory enrichment to foster restoration in break environments.

A novel approach for selecting typical hot-year (THY) weather data

The global climate change has resulted in not only warmer climate conditions but also more frequent extreme weather events, such as heat waves. However, the impact of heat waves on the indoor environment has been investigated in a limited manner. In this research, the indoor thermal environment is analyzed using a building performance simulation tool for a typical residential building in multiple cities in China, over a time period of 60 years using actual measured weather data, in order to gain a better understanding of the effect of heat wave events. The simulation results were used to analyze the indoor environment during hot summers. A new kind of weather data referred to as the typical hot year was defined and selected based on the simulated indoor environment during heat waves. The typical hot-year weather data can be used to simulate the indoor environment during extreme heat events and for the evaluation of effective technologies and strategies to mitigate against the impact of heat waves on the energy demand of buildings and human health. The limitations of the current study and future work are also discussed.

Scalable Gas Sensing, Mapping, and Path Planning via Decentralized Hilbert Maps.

This paper develops a decentralized approach to gas distribution mapping (GDM) and information-driven path planning for large-scale distributed sensing systems. Gas mapping is performed using a probabilistic representation known as a Hilbert map, which formulates the mapping problem as a multi-class classification task and uses kernel logistic regression to train a discriminative classifier online. A novel Hilbert map information fusion method is presented for rapidly merging the information from individual robot maps using limited data communication. A communication strategy that implements data fusion among many robots is also presented for the decentralized computation of GDMs. New entropy-based information-driven path-planning methods are developed and compared to existing approaches, such as particle swarm optimization (PSO) and random walks (RW). Numerical experiments conducted in simulated indoor and outdoor environments show that the information-driven approaches proposed in this paper far outperform other approaches, and avoid mutual collisions in real time.

Outstanding Indoor Performance of Perovskite Photovoltaic Cells – Effect of Device Architectures and Interlayers

Indoor photovoltaics is one of the best sustainable and reliable energy source for low power consumption electronics such as the rapidly growing Internet of Things. Perovskite photovoltaic (PPV) cells with three benchmark device architectures – mesoporous PPV (mPPV) and inverted PPV (iPPV) with alternative hole transporting layers (HTLs), and carbon‐based PPV (cPPV) are studied under a simulated indoor environment. The mPPV cell using typical Spiro‐OMeTAD as the HTL shows the highest maximum power density (Pmax) of 19.9 μW cm−2 under 200 lux and 115.6 μW cm−2 under 1000 lux (without masking), which is among the best of the indoor PV. Interestingly, when PTAA is used as the HTL in the mPPV cell, the Pmax drops to almost zero under indoor light environment while its performance under one sun remains similar. On the other hand, when PEDOT:PSS is replaced by Poly‐TPD as HTL in the iPPV cell, the Pmax under indoor light improves significantly and is comparable to that of the best mPPV cell. This significant difference in indoor performance correlates well with their leakage current. The HTL‐free cPPV cell, prepared by fully up‐scalable techniques, shows a promising Pmax of 16.3 and 89.4 μW cm−2 under 200 and 1000 lux, respectively. A practical scale 5 × 5cm2 cPPV module is fabricated as a demonstration for real applications.

Influence of atmospheric particulates on initial corrosion behavior of printed circuit board in pollution environments

It is well-known that the climate has a strong impact on the corrosion behaviour of metals, especially when the influence of haze particles in the polluted air is also taken into account. In this study, four typical climatic environments in Xishuangbanna, Wuhan, Beijing and Turpan of China were selected as outdoor exposure test sites to study the corrosion mechanism of copper-clad Printed Circult Board (PCB-Cu), respectively. Based on the analysis of the corrosion morphology of PCB-Cu after exposure test and the composition of corrosion products, corrosion behavior of PCB-Cu under outdoor and simulated indoor environments was both revealed. Under low humidity conditions such as Beijing and Turpan, haze particles absorbed on PCB-Cu could act as a original inducement of corrosion in the initial stage, which triggered the occurrence of localized corrosion in the following stage. In contrast, local corrosion caused by haze particles was not significant under higher humidity conditions in Xishuangbanna and Wuhan, where uniform corrosion on the PCB-Cu was observed.

On the use of a novel nanoporous polyethylene (nanoPE) passive cooling material for personal thermal comfort management under uniform indoor environments

Passive cooling materials such as specially designed nanoporous microfibers are nearly transparent to infrared thermal radiation emitted from the human body. Hence, such passive cooling materials have the potential to help indoor occupants attain thermal comfort through regulating the radiative body heat in indoor conditions. In this work, a regular fit women's business shirt made of the nanoporous polyethylene (nanoPE) material was designed and its cooling performance under four uniform indoor conditions was examined. A cotton shirt (CO) with the same size and pattern as the nanoPE shirt was designed and selected as the control. Eighteen female participants underwent eight 80-min trials at four indoor temperatures: 23, 25, 27 and 29 °C. Trials were performed in simulated indoor environments where RH = 60% and the air velocity was kept below 0.10 m/s. Results have demonstrated that participants had significantly lower mean skin temperatures, mean upper torso temperatures and forearm temperatures in nanoPE as compared to CO at 23, 25 and 27 °C. Participants showed the maximum satisfaction with the thermal environment while wearing the CO clothing at 25 °C, whereas they were mostly satisfied with the thermal environment while wearing the nanoPE clothing at 27 °C. Thus, the acceptable air conditioning setpoint temperature could be extended by 1.5 °C from 25.5 to 27 °C while using the nanoPE clothing and thereby, this saves about 9–15% cooling energy. Finally, it was concluded that the nanoPE passive cooling clothing contributes to enhancing indoor thermal comfort under uniform environments and saving significant cooling energy.

Device-Free Motion & Trajectory Detection via RFID

Compared with traditional methods that employ inertial sensors or wireless sensors, device-free approaches do not require that people carry devices, and they are considered a useful technique for indoor navigation and posture recognition. However, few existing methods can detect the trajectory and movements of humans at the same time. In this study, we propose a scheme called PADAR for addressing these two problems simultaneously by using passive radio frequency identification (RFID) tags but without attaching them to the human body. The idea is based on the principle of radio tomographic imaging, where the variance in a tag’s backscattered radio frequency signal strength is influenced by human movement. We integrated a commodity off-the-shelf RFID reader with a two-dimensional phased array antenna and a matrix of passive tags to evaluate the performance of our scheme. We conducted experiments in a simulated indoor environment. The experimental results showed that PADAR achieved an accuracy of over 70%.

Atmospheric corrosion factors of printed circuit boards in a dry-heat desert environment: Salty dust and diurnal temperature difference

The climate in Turpan is perennial drought with little rainfall, which usually results in the corrosion of metals. This weak corrosion can cause the paralysis of electronic components in service conditions. To study the corrosion mechanism associated with copper-clad plate (PCB-Cu) in a dry-heat desert environment, Turpan (China) was elected as an outdoor exposure site. The morphologies of the PCB-Cu and the composition of the corrosion products were analyzed. In addition, the corrosion behavior of PCB-Cu in a simulated indoor environment was also investigated. The results showed that the corrosion morphology was halo-shaped in the initial corrosion stage, which was attributed to water condensation on dust due to the large diurnal temperature difference of the environment.

INDOOR POSITIONING BY VISUAL-INERTIAL ODOMETRY

Abstract. Indoor positioning is a fundamental requirement of many indoor location-based services and applications. In this paper, we explore the potential of low-cost and widely available visual and inertial sensors for indoor positioning. We describe the Visual-Inertial Odometry (VIO) approach and propose a measurement model for omnidirectional visual-inertial odometry (OVIO). The results of experiments in two simulated indoor environments show that the OVIO approach outperforms VIO and achieves a positioning accuracy of 1.1 % of the trajectory length.

Determination and release rate of tetrachloroethylene residues in dry-cleaned fur garments

Fur garments contain residual tetrachloroethylene (PCE) from dry cleaning. Exposure to PCE can be harmful to human skin; thus, it is necessary to determine the amount of residual PCE in garments to ensure safety. This paper reports a fast, simple, and effective method for determining residual PCE using ultrasonic extraction technology combined with gas chromatography-mass spectrometry. The linear correlation coefficient of this method was 0.9999, with a low detection limit of 1.4 mg/kg. Recoveries from sheepskin leather, rabbit fur, fox fur, and raccoon fur ranged from 90.2 to 101.9 %, with relative standard deviations of 2.87-4.87 %. These results confirmed the high precision and accuracy of this new method. Meanwhile, in a simulated standard indoor environment, the 1 day and 18 day release rates for PCE residues on dry-cleaned fur garments were studied by analyzing PCE adsorption on four different materials, resulting in recommendations for storing and wearing different fur garments after dry-cleaning to ensure safety.

Learning from Demonstration in Robots using the Shared Circuits Model

Learning from demonstration presents an alternative method for programming robots for different nontrivial behaviors. Various techniques that address learning from demonstration in robots have been proposed but those do not scale up well. Thus there is a need to discover novel solutions to this problem. Given that the basic idea for such learning comes from nature in the form of imitation in few animals, it makes perfect sense to take advantage of the rigorous study of imitative learning available in relevant natural sciences. In this work a solution for robot learning from a relatively recent theory from natural sciences called the Shared Circuits Model, is sought. Shared Circuits Model theory is a comprehensive, multidiscipline representative theory. It is a modern synthesis that brings together different theories that explain imitation and other related social functions originating from various sciences. This paper attempts to import the shared circuits model to robotics for learning from demonstration. Specifically it: (1) expresses shared circuits model in a software design nomenclature; (2) heuristically extends the basic specification of Shared Circuits Model to implement a working imitative learning system; (3) applies the extended model on mobile robot navigation in a simulated indoor environment; and (4) attempts to validate the shared circuits model theory in the context of imitative learning. Results show that an extremely simple implementation of a theoretically sound theory, the shared circuits model, offers a realistic solution for robot learning from demonstration of nontrivial tasks.

Modified wavefront decomposition method for fast and accurate ray-tracing simulation

This study presents the modified wavefront decomposition method as a new ray-tracing acceleration technique for indoor propagation modelling. In this method, the exact propagation paths of the rays that reach the receiver after multiple reflections and/or refractions are calculated. Thus, the electromagnetic field at the receiver is obtained with a high accuracy. When only reflections are considered, our method simplifies to the multiple image theory or shooting and bouncing ray/image approach already available in the literature. However, the modified wavefront decomposition method calculates the exact propagation paths toward the receiver even if the rays encounter multiple refractions or a sequence of reflections and refractions. This novel contribution is specially important in indoor applications where through-the-wall propagation is usually noticeable. The significance of the proposed method is that the accuracy in the received field is obtained by shooting a few rays to the space around the transmitter. Consequently, a considerable reduction of the simulation time is achieved. The simulations show that the proposed method outperforms the traditional wavefront decomposition method. Furthermore, concurrent application of the proposed method and the previously published acceleration techniques is shown possible, which results in simulation time reduction of more than 11 times for a typical simulated indoor environment.

Indoor Millimeter Wave MIMO: Feasibility and Performance

In this paper, we investigate spatial multiplexing at millimeter (mm) wave carrier frequencies for short-range indoor applications by quantifying fundamental limits in line-of-sight (LOS) environments and then investigating performance in the presence of multipath and LOS blockage. Our contributions are summarized as follows. For linear arrays with constrained form factor, an asymptotic analysis based on the properties of prolate spheroidal wave functions shows that a sparse array producing a spatially uncorrelated channel matrix effectively provides the maximum number of spatial degrees of freedom in a LOS environment, although substantial beamforming gains can be obtained by using denser arrays. This motivates our proposed mm-wave MIMO architecture, which utilizes arrays of subarrays to provide both directivity and spatial multiplexing gains. System performance is evaluated in a simulated indoor environment using a ray-tracing model that incorporates multipath effects and potential LOS blockage. Eigenmode transmission with waterfilling power allocation serves as a performance benchmark, and is compared to the simpler scheme of beamsteering transmission with MMSE reception and a fixed signal constellation. Our numerical results provide insight into the spatial variations of attainable capacity within a room, and the combinations of beamsteering and spatial multiplexing used in different scenarios.

The Effects of Communication Style on Robot Navigation Performance

With the advance of computer speech recognition programs, robotic operators have a new method of robot-operator communication. An experiment was conducted using a “Wizard of Oz” paradigm to investigate how different styles of communication affect robot navigation performance. Using manual inputs, verbal commands (restricted to directions only), and verbal commands with object referent labels, participants navigated a simulated robot through various simulated indoor environments. Results indicated that manual control was faster than free form verbal commands but not faster than simple directional commands. When provided the opportunity, participants did use object labels particularly objects related to the structure of the building (doors, rooms, and halls). Discussion focuses on improving robotic communication and object recognition in a robotic control system.

Effectiveness of Houseplants in Reducing the Indoor Air Pollutant Ozone

Three common indoor houseplants, snake plant (Sansevieria trifasciata), spider plant (Chlorophytum comosum), and golden pothos (Epipremnum aureum), were evaluated for their species effectiveness in reducing ozone concentrations in a simulated indoor environment. Continuously stirred tank reactor (CSTR) chambers housed within a greenhouse equipped with a charcoal filtration air supply system were used to simulate an indoor environment in which ozone concentrations could be measured and regulated. Ozone was injected into the chambers and when concentrations reached 200 ± 5 ppb, the ozone-generating system was turned off and ozone concentrations over time (ozone was monitored every 5–6 min in each chamber) were recorded until about <5 ppb were measured in the treatment chamber. On average, ozone depletion time (time from when the ozone generating system was turned off at ≈200 ppb to <5 ppb in the chamber) ranged from 38 to 120 min per evaluation. Ozone depletion rates were higher within chambers that contained plants than within control chambers without plants, but there were no plant species differences.

Effectiveness of Houseplants in Reducing the Indoor Air Pollutant Ozone

Three common indoor houseplants, snake plant (Sansevieria trifasciata), spider plant (Chlorophytum comosum), and golden pothos (Epipremnum aureum), were evaluated for their species effectiveness in reducing ozone concentrations in a simulated indoor environment. Continuously stirred tank reactor (CSTR) chambers housed within a greenhouse equipped with a charcoal filtration air supply system were used to simulate an indoor environment in which ozone concentrations could be measured and regulated. Ozone was injected into the chambers and when concentrations reached 200 ± 5 ppb, the ozone-generating system was turned off and ozone concentrations over time (ozone was monitored every 5–6 min in each chamber) were recorded until about <5 ppb were measured in the treatment chamber. On average, ozone depletion time (time from when the ozone generating system was turned off at ≈200 ppb to <5 ppb in the chamber) ranged from 38 to 120 min per evaluation. Ozone depletion rates were higher within chambers that contained plants than within control chambers without plants, but there were no plant species differences.

Comparison of Environmental Tobacco Smoke (ETS) Concentrations Generated by an Electrically Heated Cigarette Smoking System and a Conventional Cigarette

Smoking conventional lit-end cigarettes results in exposure of nonsmokers to potentially harmful cigarette smoke constituents present in environmental tobacco smoke (ETS) generated by sidestream smoke emissions and exhaled mainstream smoke. ETS constituent concentrations generated by a conventional lit-end cigarette and a newly developed electrically heated cigarette smoking system (EHCSS) that produces only mainstream smoke and no sidestream smoke emissions were investigated in simulated “office” and “hospitality” environments with different levels of baseline indoor air quality. Smoking the EHCSS (International Organisation for Standardization yields: 5 mg tar, 0.3 mg nicotine, and 0.6 mg carbon monoxide) in simulated indoor environments resulted in significant reductions in ETS constituent concentrations compared to when smoking a representative lit-end cigarette (Marlboro: 6 mg tar, 0.5 mg nicotine, and 7 mg carbon monoxide). In direct comparisons, 24 of 29 measured smoke constituents (83%) showed mean reductions of greater than 90%, and 5 smoke constituents (17%) showed mean reductions between 80% and 90%. Gas–vapor phase ETS markers (nicotine and 3-ethenylpyridine) were reduced by an average of 97% (range 94–99%). Total respirable suspended particles, determined by online particle measurements and as gravimetric respirable suspended particles, were reduced by 90% (range 82–100%). The mean and standard deviation of the reduction of all constituents was 94 ± 4%, indicating that smoking the new EHCSS in simulated “office” and “hospitality” indoor environments resulted in substantial reductions of ETS constituents in indoor air.

Atmospheric corrosion of electro-electronics metals in urban desert simulated indoor environment

The corrosion of pure Ag, Cu, Ni, and Sn specimens exposed for 1 to 24 months in a simulated indoor environment, consisting of a rain sheltered atmospheric corrosion test chamber placed in an urban desert environment (Baja California) has been measured. The corrosion rates of the metals were determined by mass loss measurement and the environment was thus classified in the low to medium indoor corrosivity category (IC2–IC3) according to ISO. Silver and copper weight losses were found to be very similar, while the nickel and tin weight losses were several times lower. The silver surface was tarnished in a non-uniform manner, presenting Ag2S and AgCl corrosion products, while the copper specimens corrode uniformly, being covered with Cu2O corrosion product. Owing to the presence of chloride contamination, the nickel and tin oxide corrosion films show fracture and pitting corrosion, developed over the first few months of exposure.

Performance of Cooperative Time-Reversal Communication in a Mobile Wireless Environment

In this paper, we study the performance of a technique called time reversal for cooperative communication in a mobile wireless environment. To put the work in context, a brief introduction to time-reversal communication (TRC) in general and cooperative TRC in particular is presented. Performance of a proposed cooperative TRC scheme is evaluated numerically via a simulated indoor environment containing multiple wireless communication nodes. We characterize the behavior of the peak power received at a target node as a function of the number of cooperating transmitting nodes and as a function of the distance of the target from its predicted location within the simulated environment. The results demonstrate that the performance of cooperative TRC is less sensitive to uncertainty in the target position than might be expected from standard assumptions regarding the relationship between signal wavelength and spatial channel correlation in a complex multipath environment.