Lily M. Wang

Bio: Lily M. Wang is an academic researcher from University of Nebraska–Lincoln. The author has contributed to research in topics: Noise & Reverberation. The author has an hindex of 16, co-authored 114 publications receiving 768 citations. Previous affiliations of Lily M. Wang include Durham University.

Relationships between unoccupied classroom acoustical conditions and elementary student achievement measured in eastern Nebraska

Abstract: Building standards recommend maximum background noise levels (BNL) and reverberation times (RT) for unoccupied classrooms. However, existing research does not show a consistent correlation between these parameters and student achievement. Through in situ testing, this research seeks to determine what acoustical conditions should be attained in elementary schools for students to meet educational goals. Acoustical measurements were conducted in a Nebraska public school system and correlated to achievement scores from students in the surveyed classrooms. Unoccupied BNLs and RTs were gathered in 34 third and 33 fifth-grade classrooms. Additionally, binaural room impulse response measurements were gathered in a subset of the classrooms. The results suggest that student reading and language subject areas may be negatively impacted by higher unoccupied BNLs; to meet the upper half of NE state targets, these levels should be less than 45 dBA. However, the percentage of students receiving free or reduced price lunches is more strongly correlated to achievement than BNLs, and the negative correlations between noise and achievement are not significant when controlling for this demographic variable. One statistically significant relationship that remained when controlling for demographics was that classrooms with lower distortion of frequency-smoothed magnitude values generally had students with higher language scores.

The effects of simple coupled volume geometry on the objective and subjective results from nonexponential decay

Abstract: This project focuses on the individual and interactive acoustic effects of three architectural parameters on the double slope profile from a simple coupled volume system created in the computer modeling program ODEON. The three variables studied are the volume ratio between the main and secondary spaces, the absorption ratio between the two spaces, and aperture size. The resulting energy decay profiles are analyzed using T30∕T15 coupling coefficient ratios and Bayesian analysis. Coupling coefficient results show general trends in the effects of the three architectural parameters that match previous research results and the predominant interactive effect between the three variables involving a large coupled volume. Similar results are suggested by the Bayesian analysis based on the newly developed quantifiers, decay ratio and ΔdB, although a more complex relationship among the variables may exist at larger volume ratios. A subset of the simulated sound fields have been auralized and used to conduct psychoa...

Implications of Human Performance and Perception under Tonal Noise Conditions on Indoor Noise Criteria

Abstract: This research investigated differences in task performance and perception under six non-time-varying ventilation-type background noise spectra with differing tonality. The results were related to five indoor noise criteria systems: noise criteria, balanced noise criteria, room criteria, room criteria mark II, and the A-weighted equivalent sound pressure level (LAeq). These criteria systems are commonly used in the U.S. building industry, but concerns exist over whether they are appropriate for all noise situations. Thirty test subjects completed three types of performance tasks (typing, reasoning, and math) and answered questions about their perception of the indoor environment under each noise condition. Results showed that performance scores did not change significantly across the six noise conditions, but there were differences in subjective perception. For example, perception trends for tonality, annoyance, and distraction changed based on the frequency and prominence of discrete tones in noise. Howev...

Thermal comfort and gender: a literature review

Abstract: This review examines scientific literature on the effect of gender on indoor thermal comfort. Gender differences have been generally considered to be small and insignificant but this review shows that a growing number of studies have found significant differences in thermal comfort between the genders. Clearly more than half of the laboratory and field studies have found that females express more dissatisfaction than males in the same thermal environments. Very few studies have found males to be more dissatisfied than females. A meta-analysis shows that females are more likely than males to express thermal dissatisfaction (ratio: 1.74, 95% confidence interval: 1.61–1.89). However, most studies found no significant difference in neutral temperatures between the genders. Females are more sensitive than males to a deviation from an optimal temperature and express more dissatisfaction, especially in cooler conditions. Practical Implications We should no longer neglect the more rigorous requirements that females have for indoor thermal environments. Gender differences indicate that females have, on average, a greater need for individual temperature control and adaptive actions than males. The results of this review suggest that females should primarily be used as subjects when examining indoor thermal comfort requirements, as if females are satisfied it is highly probable that males are also satisfied.

Quantitative relationships between occupant satisfaction and satisfaction aspects of indoor environmental quality and building design

Abstract: Author(s): Frontczak, Monika; Schiavon, Stefano; Goins, John; Arens, Edward A; Zhang, Hui, Ph.D; Wargocki, Pawel | Abstract: The paper examines which subjectively evaluated indoor environmental parameters and building features mostly affect occupants’ satisfaction in mainly US office buildings. The study analyzed data from a web-based survey administered to 52,980 occupants in 351 office buildings over ten years by the Center for the Built Environment. The survey uses 7-point ordered scale questions pertaining to satisfaction with indoor environmental parameters, workspace and building features. The average building occupant was satisfied with his/her workspace and building. Proportional odds ordinal logistic regression shows that satisfaction with all 15 parameters listed in the survey contributed significantly to overall workspace satisfaction. The most important parameters were satisfaction with amount of space (odds ratio OR 1.57, CI: 1.55-1.59), noise level (OR 1.27, CI: 1.25-1.29) and visual privacy (OR 1.26, CI: 1.24-1.28). Satisfaction with amount of space was ranked to be the most important influence for workspace satisfaction, regardless of age group (below 30, 31-50 or over 50 years old), gender, type of office (single or shared offices, or cubicles), distance of workspace from a window (within 4.6 m or further) or satisfaction level with workspace (satisfied or dissatisfied). Satisfaction with amount of space was not related to the gross amount of space available per person.PRACTICAL IMPLICATIONSTo maximize workspace satisfaction designer should invest in aspects which increase satisfaction with amount of space and storage, noise level and visual privacy. Office workers will be most satisfied with their workspace and building when located close to a window in a private office. This may affect job satisfaction, work performance and personal and company productivity.