Rooms Of Different Sizes Research Articles

Indoor air pollutants and their seasonal monitoring in European museums

The monitoring of indoor air pollutants is an important part of the management of heritage collections. In this work, acetic acid, formic acid, formaldehyde, acetaldehyde and NO2 were measured with passive samplers along with temperature and relative humidity once per season in seven European institutions of different sizes with different types of objects. The measurements were carried out in a variety of locations, from modern and old display cases in exhibition rooms of different sizes to storage rooms and their enclosures for different types of objects. The results were evaluated based on the characteristics of the sampling locations and the extent to which the changing seasons affect pollutant concentrations were estimated. The dataset obtained from this study can be a valuable asset as a snapshot of the current state of the environment in European heritage collections.

Performance Evaluation of Wi-Fi RTT Lateration without Pre-Constructing a Database

This paper proposes an algorithm for estimating the location of wireless access points (APs) in indoor environments to realize smartphone positioning based on Wi-Fi without pre-constructing a database. The proposed method is designed to overcome the main problem of existing positioning methods requiring the advance construction of a database with coordinates or precise AP location measurements. The proposed algorithm constructs a local coordinate system with the first four APs that are activated in turn, and estimates the AP installation location using Wi-Fi round-trip time (RTT) lateration and the ranging results between the APs. The effectiveness of the proposed algorithm is confirmed by conducting experiments in a real indoor environment consisting of two rooms of different sizes to evaluate the positioning performance of the algorithm. The experimental results showed the proposed algorithm using Wi-Fi RTT lateration delivers high smartphone positioning performance without a pre-constructed database or precise AP location measurements.

Comparison between Predictive and Measurement Methods of Speech Intelligibility for Educational Rooms of Different Sizes with and without HVAC Systems

Heating ventilation and air conditioning (HVAC) systems represent one of the main noise sources inside classrooms. This explain why HVAC systems require careful design, competent installation and balancing, and regular maintenance. Many factors influence the classroom acoustical design, such as air handlers or fans, the velocity of air inside the classroom, as well as the size and acoustical treatment of ducts, returns, and diffusers. Acoustic parameters, including background-noise levels, reverberation time, and intelligibility, were analyzed in 17 classrooms at the Università Politecnica in the Marche region. The study of intelligibility was performed by measuring the objective parameters in situ and using prediction methods to determine the intelligibility score. The relationship between speech intelligibility measurements and speech intelligibility calculation has been studied. The relationship between the STI values with the background-noise levels and the reverberation time was also studied. This research shows that a comparison between predictive methods and measurement methods results in speech intelligibility for classrooms of different sizes with and without HVAC systems. The current method of calculating the voice transmission index (STI), proposed by national and international standards, has been used to determine speech intelligibility scores in classrooms. The results show that the calculation tool has computational robustness allowing its use in preliminary evaluations of speech intelligibility, design of the optimal type of school buildings, and sound amplification systems in classrooms that comply with Italian regulations.

An overview of the proposed new ASTM standard for impulse response measurements using swept sinusoidal signals

This contribution presents the current draft of the proposed ASTM standard for impulse response measurements using swept sinusoidal signals for use in room and building acoustics. After briefly discussing the theoretical background and main body of the proposed standard, the main focus of the presentation is the validation procedure to compare reverberation time measurements between the interrupted noise method and the impulse response method. The challenges and associated uncertainties of the validation procedure are discussed, and preliminary results for rooms of different sizes are shown.

Experimental study on the effect of fire alarms on occupants for situational awareness and evacuation decision‐making using a mobile virtual reality head‐mounted display

AbstractFire alarms play a significantrole in situational awareness and decision‐making pertaining to evacuation for fire evacuation safety in office buildings that include small rooms, where many occupants cannot directly see fire or smoke. We conducted experiments using a mobile VR head‐mounted display to examine how individuals perceive the sound of fire alarms in rooms of different sizes. Comparing the cases of hearing the alarm sound in the large room and the small room, approximately 70% of the test participants answered that they wanted to check the situation more when they were in the small room because they could not understand the surrounding situation. Regardless of the room size, when test participants hear the early warning voice, approximately 40% of them would check the neighborhood and evacuate, and when they hear the evacuation directive voice alarm, more than 90% will take the same action. We also discussed the awareness process of occupants considering this result and the configuration of a smoke detection system in Japan. Approximately half of the people in the large room take checking actions; however, the remaining people do not take specific confirmation actions for about 1–3 min and do not check for fires or evacuate.

RAMP summer bridge: Room acoustics: Connecting research, academics and mentoring

The Research, Academics and Mentoring Pathways (RAMP) to Success summer bridge program at the University of Massachusetts Lowell prepares new engineering students from all majors for an early transition from high school to college. Over the last five years, RAMP has engaged 107 students, the majority being women and underrepresented minorities, in a six-week research, academics and mentoring experience. During RAMP, students are enrolled in Calculus and Introduction to Engineering courses, earning six credits towards their degree pathway. Groups of 5–6 students take on research projects with engineering faculty while also meeting weekly with professionals from industry. The structuring of a room acoustics research project is presented. A project-based learning model helps build skills in collaborative problem solving while also supporting each student to find authentic interest in the research. The project integrates experiments on measuring room impulse responses and spatial variation of source pressure amplitude in rooms of different sizes with a model-driven analysis of the data collected. Concepts of reverberation time, backward integration and room constants reinforce calculus concepts being studied. Coding experiments on rendering speech and music through measured impulse responses and filters created interest across a range of acoustics topics from concert halls to virtual audio.

Model prediction of the purification time when PM2.5 is removed unevenly by an air purifier

The portable air purifier can't uniformly remove the PM2.5 at each personnel position in a room, which causes the unevenness of PM2.5 distribution. In order to achieve priority purification of PM2.5 at the personnel position, experiments and simulations were conducted here to determine the time required for the purifier to reduce the PM2.5 concentration in a room to 15 μg/m3 (hereafter referred to as the purification time) in each area of the room at different wind speeds. SPSS was used to conduct regression analysis of the simulated data and determine the contribution rate of each impact factor, and assess the prediction model for the purification time. This prediction model can be used to calculate the purification time of any location in rooms of different sizes. The results show that, there was a nonlinear relationship between the purification time and impact factors, however, when the purifier wind speed is determined, PM2.5 purification time shows a linear relationship with the remaining impact factors. The contribution rate of the initial PM2.5 concentration to the purification time was largest. Increasing the wind speed will further increase the contribution rate of the initial PM2.5 concentration, but reduce the contribution rate of the air supply angle, personnel distance, and personnel angle.

Die Benennung und Bestimmung der Räume im südlichen Repräsentativteil des Geschosses des zweiten „Hochmeisterpalastes“ auf der Marienburg im Mittelalter im Lichte der Schriftquellen

Nomenclature and intended use of the rooms of the southern (representative) part of the upper floor of the “palace” of Grand Masters in the Marienburg Castle in the Middle Ages on the basis of written sources The analyses carried out in this article concerning the southern part of the upper floor of the new (second) “palace” of the Teutonic Order’s superiors in the late Middle Ages allow to formulate several important conclusions. First of all, the building certainly existed before 11 September 1392, but it cannot be ruled out that it was erected at the beginning of the 1370s. In the fifteenth-century sources, its entire southern representative part (looking from the so-called Low and High Halls) along with five rooms of different sizes located there, were referred to as the “Summer (or, less often, Winter) chamber (gemach)”. This name comes from the most characteristic interiors located there: the “Summer Refectory” / “Great Summer Hall” in the western part and the Winter Refectory in the central part. The thorough analysis of medieval written sources carried out in this article allows for the formulation of the thesis that the chamber located in the easternmost part of the southern part of the “palace”, supported by two columns, should be identified as the “Minor Summer Hall” (aula minor estivalis), which was recorded in the transumpt of 14 May 1456. Thus, all the suggestions concerning this interior and its supposed intended use in the discussed period, hitherto put forward by the researchers who have so far formulated their conclusions in isolation from the written accounts of the period, should be rejected. This name comes from the most characteristic interiors located there: the "Summer Refectory" / "Great Summer Hall" in the western part and the Winter Refectory in the central part. The thorough analysis of medieval written sources carried out in this article allowed for the formulation of the thesis that the chamber located in the easternmost part of the southern part of the "palace", supported by two columns, should be identified as the "Minor Summer Hall" (aula minor estivalis), which was recorded in the transumpt of 14 May 1456. Thus, all the suggestions concerning this interior and its supposed intended use in the discussed period, hitherto put forward by the researchers who have so far formulated their conclusions in isolation from the written accounts of the period, should be rejected.

Assessment of speech intelligibility in university lecture rooms of different sizes using objective and subjective methods

The scores of speech intelligibility, obtained using objective and subjective methods for three university lecture rooms of the small, medium, and large sizes with different degrees of filling, were presented. The problem of achieving high speech intelligibility is relevant for both students and university administration, and for architects designing or reconstructing lecture rooms. Speech intelligibility was assessed using binaural room impulse responses which applied an artificial head and non-professional quality audio equipment for measuring. The Speech Transmission Index was an objective measure of speech intelligibility, while the subjective evaluation of speech intelligibility was carried out using the articulation method. Comparative analysis of the effectiveness of parameters of impulse response as a measure of speech intelligibility showed that Early Decay Time exceeded the score of the T30 reverberation time but was ineffective in a small lecture room. The C50 clarity index for all the considered lecture rooms was the most informative. Several patterns determined by the influence of early sound reflections on speech intelligibility were detected. Specifically, it was shown that an increase in the ratio of the energy of early reflections to the energy of direct sound leads to a decrease in speech intelligibility. The exceptions are small, up to 30‒40 cm, distances from the back wall of the room, where speech intelligibility is usually slightly higher than in the middle of the room. At a distance of 0.7–1.7 m from the side walls of the room, speech intelligibility is usually worse for the ear, which is closer to the wall. The usefulness of the obtained results lies in refining the quantitative characteristics of the influence of early reflections of sound on speech intelligibility at different points of lecture rooms.

Ergonomic Auditory Alarm Signals for the Oil and Chemical Processing Industry

OCCUPATIONAL APPLICATIONS Auditory alarm signals are a safety measure that would benefit from improvement across many industries. There is a considerable research base that can be applied to the development and testing of audible alarms, though this is rarely done in practice. We describe a process that can be adopted in any area where audible alarm signals are widespread. A comprehensive approach to updating and improving auditory alarms requires consideration not only of individual alarm sounds but also of how the alarm signals will work together. We show the development and design of alarm signal sets following best practices from acoustic, psychoacoustic, and psychological knowledge to ensure that the resultant alarms are localizable, audible, easy to learn, appropriately urgency-mapped, and differentiable. We also describe benchmarking tests, and a protocol for thinking about how auditory alarm signals might be implemented in control rooms of different sizes.

The effect of a mobile HEPA filter system on ‘infectious’ aerosols, sound and air velocity in the SenseLab

High efficiency air filtration has been suggested to reduce airborne transmission of ‘infectious’ aerosols. In this study the ‘air cleaning’ effect as well as the effect on sound and air velocity (draught risk) of a mobile High-Efficiency Particulate Air (HEPA) filter system was tested for different settings and positions in the Experience room of the SenseLab. From both the noise assessments by a panel of subjects and sound monitoring it was concluded that the mobile HEPA filter system causes an unacceptable background sound level in the tested classroom setting (Experience room). With respect to the air velocity measurements and draught rating calculations, it was concluded that both depend on the position and the setting of the HEPA filter system as well as on the position and height of the measurements. For the removal of aerosols simulated by air-filled soap bubbles in front of the subject, the mobile HEPA filter system performed better as compared to the ‘No ventilation’ regime, for all settings and both positions, and for some settings, even better than all the tested mixing ventilation regimes. The use of a mobile HEPA filter system seems a good additional measure when only natural ventilation options are available. Future research should focus on rooms of different sizes or shapes, as this may also play a role in the filter's performance, noise and draught effects.

Threshold Behavior of Democratic Opinion Dynamics

Consider a community where initially, each individual is positive or negative regarding a reform proposal. In each round, individuals gather randomly in fixed rooms of different sizes, and all individuals in a room agree on the majority opinion in the room (with ties broken in favor of the negative opinion). The Galam model—introduced in statistical physics, specifically sociophysics—approximates this basic random process. We approach the model from a more mathematical perspective and study the threshold behavior and the consensus time of the model.

Definition of a composite index of glazing rooms

The effect of geometrical parameters of rooms and window openings on the value of the daylight factor (DF) in the reference point on the work surface is considered in the article. This is important, as while using a light factor (LF) and a window-to-wall ratio (WWR), there is a significant error. Therefore, there are objective difficulties with the unification of the results of studies on the effectiveness of natural sidelight, which are due to the influence of the size of the room on the DF value in the reference point on the work surface.The use of the above-mentioned coefficients to evaluate the efficiency of lateral natural light results in the fact that, at constant value of the coefficient, the value of the DF may differ several times. This is because the area of the window opening does not correspond to the area of glazing through which daylight passes into the room. The area of the room does not correspond to the area of the work surface on which it is necessary to provide normalized illumination, and the dimensions of both the room and the work surface are not taken into account in the LF or in the WWR at all.It is proposed to use a composite room glazing index (CRGI). It takes into account not only the glazing area of the window opening but also the dimensions and area of the work surface. This makes it possible to use the results of studies on the effectiveness of natural light without binding them to the dimensions of a room. Using the Relux program, the DF value in the reference point for rooms of different sizes with different glazing areas of the window openings is calculated and the dependence of the DF on the CRGI has been obtained. As a result of the approximation of this dependence, an equation describing the relationship between these quantities has been developed.An algorithm that takes into account both the width of the opaque portion of the window opening and its proportion has been developed to determine the area of the window opening at which the required value of the DF in the reference point is provided. The obtained scientific result in the forms of the CRGI and algorithm of calculating the area of the window opening is interesting from the theoretical point of view. From a practical point of view, the results help calculate the minimum glazing area of the window opening to provide a normalized DF value with a standard deviation of 0.894, based solely on the dimensions of the room. This is a prerequisite for using the obtained results in the development of normative documents for construction sites

Fast estimation of Speech Transmission Index using the Reverberation Time: Comparison between predictive equations for educational rooms of different sizes

Ensuring a high speech intelligibility is an essential issue for educational rooms, especially in relation to the effectiveness of the student learning process. The Reverberation Time and the Speech Transmission Index are objective parameters commonly used to assess the acoustic quality of the rooms, according to their intended use. Especially the Speech Transmission Index can give interesting information about the speech intelligibility. As with the Reverberation Time, it would be very important to have simple equations aimed to the prediction of Speech Transmission Index values during the early design stage. There are different studies in the literature that propose equations, obtained on empirical basis, for a fast estimation of the Speech Transmission Index as a function of the Reverberation Time. In this paper, a comparison of the most significant equations proposed in the literature was done using the Reverberation Time and Speech Transmission Index values obtained from a measurement campaign at the School of Engineering of the University of Pisa on a sample of 11 educational rooms. The analysis was carried out for educational rooms of different sizes, in order to highlight differences in the prediction accuracy depending on the volume of the rooms. From the analysis results it was possible to highlight the equation that shows the best accuracy in predicting the experimental data for the sample of investigated rooms and propose, through a regression analysis, two new equations for the rapid estimation of the Speech Transmission Index.

The speakers in the room corpus

The speakers in the room (SITR) corpus is a collaboration between Lab41 and SRI International, designed to be a freely available data set for speech and acoustics research in noisy room conditions. The main focus of the corpus is on distant microphone collection in a series of four rooms of different sizes and configurations. There are both foreground speech and background adversarial sounds, played through high-quality speakers in each room to create multiple, realistic acoustic environments. The foreground speech is played from a randomly rotating speaker to emulate head motion. Foreground speech consists of files from LibriVox audio collections and the background distractor sounds will consist of babble, music, HVAC, TV/radio, dogs, vehicles, and weather sounds drawn from the MUSAN collection. Each room has multiple sessions to exhaustively cover the background foreground combinations, and the audio is collected with twelve different microphones (omnidirectional lavalier, studio cardioid, and piezoelectric) placed strategically around the room. The resulting data set was designed to enable acoustic research on event detection, background detection, source separation, speech enhancement, source distance, sound localization, as well as speech research on speaker recognition, speech activity detection, speech recognition, and language recognition.

Determining the accuracy of sound field synthesis systems in reproducing subjective source locations

Sound field synthesis systems developed and applied to study human hearing perception differ in terms of the number and arrangement of loudspeakers in rooms of different sizes, and methods used to generate virtual sound environments. Research has evaluated how well such systems physically reproduce room acoustic conditions, but limited subjective data are available. This paper seeks to develop a method for determining the accuracy of the perceived localization of a virtual sound source generated using a multichannel sound synthesis system. A test method is applied to the sound field synthesis facility at Boys Town National Research Hospital, a room (5.8 m x 5.2 m x 2.7 m) with reverberation time of 0.16 s at 125 Hz and below 0.024 s at 250 Hz and above. Short bursts of broadband speech-shaped noise are presented at a number of virtual source locations under free-field and modeled reverberant-room conditions, and listeners are asked to point to the subjective source location. Subjective localization results are compared as functions of virtual sound location, and parameters of early reflections and reverberation in the modeled sound environment. Results are intended to guide future research on subjective room acoustics relevant to children's’ communication needs. [Work supported by NIH GM109023.]

Noise Calculation Method for Industrial Premises with Bulky Equipment at Mirror-diffuse Sound Reflection

The paper presents a method of sound energy characteristics calculation in premises with bulky equipment at mirror-diffuse character of sound reflection from enclosures. At such character of reflection a part of sound energy falling on an enclosure is reflected specularly, and the other part is dissipated under the Lamberts law. Sound pressure levels in reference points of a premise are determined by the sum of direct sound energy emitted by sound sources and energy of mirror and diffuse components of reflected sound field. The numerical method is proposed for calculation of sound energy density and the subsequent determination of sound pressure levels. The method is developed on the basis of the combined design model in which the mirror component of the reflected sound energy is determined by ray-tracing method and the diffuse energy component is calculated by numerical statistical energy method. The equations for determination of density of the direct, mirror-reflected and diffused sound energy are provided and technique of realization of the design model is given. The proposed method takes into account space-planning features of premises, presence of bulky equipment, sound absorption characteristics of enclosures and the nature of sound reflection from surfaces, and provide an opportunity to solve problems of estimating noise in industrial premises. The comparison of the calculated and experimental data obtained for rooms of different sizes and shapes in the absence and presence of bulky equipment confirmed the adequacy of the proposed calculation model for the description of noise field formation in such conditions. It is shown that divergences of calculation and experimental data do not exceed ±2÷3dB in octave bands with central frequencies equal or more than 250Hz.

Changes in room acoustics elicit a Mismatch Negativity in the absence of overall interaural intensity differences

Changes in room acoustics provide important clues about the environment of sound source-perceiver systems, for example, by indicating changes in the reflecting characteristics of surrounding objects. To study the detection of auditory irregularities brought about by a change in room acoustics, a passive oddball protocol with participants watching a movie was applied in this study. Acoustic stimuli were presented via headphones. Standards and deviants were created by modelling rooms of different sizes, keeping the values of the basic acoustic dimensions (e.g., frequency, duration, sound pressure, and sound source location) as constant as possible. In the first experiment, each standard and deviant stimulus consisted of sequences of three short sounds derived from sinusoidal tones, resulting in three onsets during each stimulus. Deviant stimuli elicited a Mismatch Negativity (MMN) as well as two additional negative deflections corresponding to the three onset peaks. In the second experiment, only one sound was used; the stimuli were otherwise identical to the ones used in the first experiment. Again, an MMN was observed, followed by an additional negative deflection. These results provide further support for the hypothesis of automatic detection of unattended changes in room acoustics, extending previous work by demonstrating the elicitation of an MMN by changes in room acoustics.

Estimation of scattering contribution in the calibration of neutron devices with radionuclide sources in rooms of different sizes

Calibrations of neutron devices used in area monitoring are often performed by radionuclide neutron sources. Device readings increase due to neutrons scattered by the surroundings and the air. The influence of said scattering effects have been investigated in this paper by performing Monte Carlo simulations for ten different radionuclide neutron sources inside several sizes of concrete wall spherical rooms (Rsp = 200 to 1500 cm). In order to obtain the parameters that relate the additional contribution from scattered neutrons, calculations using a polynomial fit model were evaluated. Obtained results show that the contribution of scattering is roughly independent of the geometric shape of the calibration room. The parameter that relates the room-return scattering has been fitted in terms of the spherical room radius, so as to reasonably accurately estimate the scattering value for each radionuclide neutron source in any geometry of the calibration room.

Opening window issue of residential buildings in winter in north China: A case study in Shenyang

Mechanical ventilation systems aren’t installed in most residential buildings in north China and the residents generally rely on opening windows to improve the indoor air quality. Heat loses drastically in minutes of natural ventilation due to great indoor and outdoor temperature difference in winter. A winter survey, including 500 random subjects interviewed face to face, was conducted in Shenyang aiming to present the opening window status of the residents, ascertain the features of indoor thermal sensation, house area, storey number, time at home, household number, feeling of indoor air quality and health consciousness and reflections of these features on the opening window habit. Furthermore, a winter test of air change rate (ACR) of opening windows, which is positively correlated to heat loss, was conducted in rooms of different sizes of a typical residential building. According to the analysis based on Chi-square (χ2) test, subjective feeling of indoor air quality and personal health consciousness were found to be significantly correlated with residents’ opening window habit. In the case of Shenyang, some rules of the effect of room size, wind direction and window opening size on ACR in winter were discovered and a few suggestions on people's opening window habit were provided.