Research

Accelerated Compressed Sensing Based CT Image Reconstruction
Accelerated Compressed Sensing Based CT Image Reconstruction
In X-ray computed tomography (CT) an important objective is to reduce the radiation dose without significantly degrading the image quality. Compressed sensing (CS) enables the radiation dose to be reduced by producing diagnostic images from a limited number of projections. However, conventional CS-based algorithms are computationally intensive and time-consuming. We propose a new algorithm that accelerates the CS-based reconstruction by using a fast pseudopolar Fourier based Radon transform and rebinning the diverging fan beams to parallel beams. The reconstruction process is analyzed using a maximum-a-posterior approach, which is transformed into a weighted CS problem. The weights involved in the proposed model are calculated based on the statistical characteristics of the reconstruction process, which is formulated in terms of the measurement noise and rebinning interpolation error .Therefore, the proposed method not only accelerates the reconstruction, but also removes the rebinning and interpolation errors. Simulation results are shown for phantoms and a patient. For example, a 512 × 512 Shepp-Logan phantom when reconstructed from 128 rebinned projections using a conventional CS method had 10% error, whereas with the proposed method the reconstruction error was less than 1%.Moreover, computation times of less than 30 sec were obtained using a standard desktop computer without numerical optimization., Hashemi, S., Beheshti, S., Gill, P. R., Paul, N. S., & Cobbold, R. S. C. (2015). Accelerated compressed sensing based CT image reconstruction. Computational and Mathematical Methods in Medicine, 2015, 1-16. doi:10.1155/2015/161797
Accessibility to health care facilities in Montreal Island: an application of relative accessibility indicators from the perspective of senior and non-senior residents
Accessibility to health care facilities in Montreal Island: an application of relative accessibility indicators from the perspective of senior and non-senior residents
Background Geographical access to health care facilities is known to influence health services usage. As societies age, accessibility to health care becomes an increasingly acute public health concern. It is known that seniors tend to have lower mobility levels, and it is possible that this may negatively affect their ability to reach facilities and services. Therefore, it becomes important to examine the mobility situation of seniors vis-a-vis the spatial distribution of health care facilities, to identify areas where accessibility is low and interventions may be required. Methods Accessibility is implemented using a cumulative opportunities measure. Instead of assuming a fixed bandwidth (i.e. a distance threshold) for measuring accessibility, in this paper the bandwidth is defined using model-based estimates of average trip length. Average trip length is an all-purpose indicator of individual mobility and geographical reach. Adoption of a spatial modelling approach allows us to tailor these estimates of travel behaviour to specific locations and person profiles. Replacing a fixed bandwidth with these estimates permits us to calculate customized location- and person-based accessibility measures that allow inter-personal as well as geographical comparisons. Data The case study is Montreal Island. Geo-coded travel behaviour data, specifically average trip length, and relevant traveller's attributes are obtained from the Montreal Household Travel Survey. These data are complemented with information from the Census. Health care facilities, also geo-coded, are extracted from a comprehensive business point database. Health care facilities are selected based on Standard Industrial Classification codes 8011-21 (Medical Doctors and Dentists). Results Model-based estimates of average trip length show that travel behaviour varies widely across space. With the exception of seniors in the downtown area, older residents of Montreal Island tend to be significantly less mobile than people of other age cohorts. The combination of average trip length estimates with the spatial distribution of health care facilities indicates that despite being more mobile, suburban residents tend to have lower levels of accessibility compared to central city residents. The effect is more marked for seniors. Furthermore, the results indicate that accessibility calculated using a fixed bandwidth would produce patterns of exposure to health care facilities that would be difficult to achieve for suburban seniors given actual mobility patterns. Conclusions The analysis shows large disparities in accessibility between seniors and non-seniors, between urban and suburban seniors, and between vehicle owning and non-owning seniors. This research was concerned with potential accessibility levels. Follow up research could consider the results reported here to select case studies of actual access and usage of health care facilities, and related health outcomes., Paez, A., Mercado, R. G., Farber, S., Morency, C., & Roorda, M. (2010). Accessibility to health care facilities in montreal island: An application of relative accessibility indicators from the perspective of senior and non-senior residents. International Journal of Health Geographics, 9(1), 52-52. doi:10.1186/1476-072X-9-52
Acoustic Intervention in a Cultural Heritage: The Chapel of the Royal Palace in Caserta, Italy
Acoustic Intervention in a Cultural Heritage: The Chapel of the Royal Palace in Caserta, Italy
The modern use of ancient heritage sites can be, to say the least, challenging from an acoustical perspective. In fact, modern needs may require acoustical interventions in contrast with the preservation issues of the cultural heritage. This paper deals with this topic in an UNESCO designated world heritage site, the Palatine Chapel of the Royal Palace in Caserta, Italy. Since this chapel is currently being used for meetings and music chamber concerts, the acoustical characteristics of the chapel, originally used for religious purposes, are investigated. Field measurements were undertaken to evaluate the acoustical performance of the empty chapel. The measurements were then used to calibrate and validate a computer simulation model. Different acoustical treatments are then considered and simulations are used to determine the related acoustical improvements. Finally, the benefits of different acoustical treatments which are respectful of the aesthetic and historical value of this cultural heritage are discussed., Berardi, U., Iannace, G., & Ianniello, C. (2015;2016;). Acoustic intervention in a cultural heritage: The chapel of the royal palace in caserta, italy. Buildings, 6(1), 1. doi:10.3390/buildings6010001, (This article belongs to the Special Issue Selected Papers on Building and Architectural Acoustics from ICSV22)
Acoustics of a Music Venue/Bar—A Case Study
Acoustics of a Music Venue/Bar—A Case Study
A vacant unit, once used by a Portuguese Deli, was converted to a bar/music room in Toronto. The unit was divided into two spaces along its north-south axis. The western portion was designed as a music room that would provide a performance space from a solo artist to a Jazz combo to a small rock band. The eastern part was designed as a regular bar/dining area. The plan also called for a microbrewery unit at the back of the unit. The bar music can be loud, while the music room can be pianissimo to forte depending on the type of performance. The acoustical design aspects are critical for the music room. In addition, the acoustical separation between the two spaces is equally important. The music room/bar is currently in use. The design results are compared to actual field measurements. The results showed that the music venue performed satisfactorily. The acoustical separation between the music venue and the bar/restaurant was better than expected other than an installation deficiency of the south side sound lock doors. The background sound along the northern portion was NC-35 or less. However, the southern portion’s background sound exceeded NC-35 due to the hissing of the return air grille. The acoustical design and the performance results of the music venue-bar/restaurant are presented in this paper., Ramakrishnan, R., & Dumoulin, R. (2016). Acoustics of a music venue/bar—A case study. Buildings, 6(1), 11. doi:10.3390/buildings6010011, (This article belongs to the Special Issue Selected Papers on Building and Architectural Acoustics from ICSV22)
Action Research in OHS - Shifting from Hypothesis Testing to Experiential Learning?
Action Research in OHS - Shifting from Hypothesis Testing to Experiential Learning?
For more details see the case study example: Neumann, W.P., Ekman, M. and Winkel, J., 2009. Integrating ergonomics into system development - The Volvo Powertrain Case. Applied Ergonomics, 40(3): 527-537. doi:10.1016/j.apergo.2008.09.010
Active Collection of Land Cover Sample Data from Geo-Tagged Web Texts
Active Collection of Land Cover Sample Data from Geo-Tagged Web Texts
Sample data plays an important role in land cover (LC) map validation. Traditionally, they are collected through field survey or image interpretation, either of which is costly, labor-intensive and time-consuming. In recent years, massive geo-tagged texts are emerging on the web and they contain valuable information for LC map validation. However, this kind of special textual data has seldom been analyzed and used for supporting LC map validation. This paper examines the potential of geo-tagged web texts as a new cost-free sample data source to assist LC map validation and proposes an active data collection approach. The proposed approach uses a customized deep web crawler to search for geo-tagged web texts based on land cover-related keywords and string-based rules matching. A data transformation based on buffer analysis is then performed to convert the collected web texts into LC sample data. Using three provinces and three municipalities directly under the Central Government in China as study areas, geo-tagged web texts were collected to validate artificial surface class of China’s 30-meter global land cover datasets (GlobeLand30-2010). A total of 6283 geo-tagged web texts were collected at a speed of 0.58 texts per second. The collected texts about built-up areas were transformed into sample data. User’s accuracy of 82.2% was achieved, which is close to that derived from formal expert validation. The preliminary results show that geo-tagged web texts are valuable ancillary data for LC map validation and the proposed approach can improve the efficiency of sample data collection., Hou, D., Chen, J., Wu, H., Li, S., Chen, F., & Zhang, W. (2015). Active collection of land cover sample data from geo-tagged web texts. Remote Sensing, 7(5), 5805-5827. doi:10.3390/rs70505805
Adapting Engineering Design Tools to Include Human Factors
Adapting Engineering Design Tools to Include Human Factors
OCCUPATIONAL APPLICATIONS In a longitudinal collaboration with engineers and human factors specialists at an electronics manufacturer, five engineering design tools were adapted to include human factors. The tools, many with required human factors targets, were integrated at each stage of assembly design to increase the proactive application of human factors. This article describes the process of adapting the five tools within the collaborating organization. Findings suggest 12 key features of human factors tools, most importantly that they “fit” with engineering processes, language, and tools; directly address business goals and influence key metrics; and are quantifiable and can demonstrate change. To be effective in an engineering design environment, it is suggested that human factors specialists increase their understanding of their organization’s design process, learn which tools are commonly used in engineering, focus on important metrics for the business goals, and incorporate human factors into engineering-based tools and worksystem design practices in their organizations. TECHNICAL ABSTRACT Rationale: Design engineers use diverse tools in design, but few incorporate human factors, even though optimizing human performance can further improve operational performance. There is a need for practical tools to help engineers integrate human factors into production design processes. Purpose: This article demonstrates how five engineering design tools were adapted to include human factors and were integrated into design processes within the case study organization. It also provides features of an effective human factors tool and recommendations for practitioners. Method: A longitudinal collaboration with engineers and human factors specialists in a large electronics manufacturing organization allowed in vivo adaptation and testing of various tools in an action research methodology. Qualitative data were recorded from multiple sources, then transcribed and analyzed over a 3-year period. Results: The adapted tools integrated into each stage of the design process included the human factors process failure mode effects analysis, human factors design for assembly, human factors design for fixtures, workstation efficiency evaluator, and human factors kaizens. Each tool had a unique participatory development process; 12 features are recommended for effective human factors tools based on the findings herein. Most importantly, tools should “fit” with existing engineering processes, language, and tools; directly address business goals and influence key metrics; and be quantifiable and demonstrate change. Conclusions: Engineers and management responded positively to the five tools adapted for human factors because they were designed to help improve assembly design and achieve their business goals. Several of the human factors tools became required targets within the design process, ensuring that human factors considerations are built into all future design processes. Adapting engineering tools, rather than using human factors tools, required a shift for human factors specialists, who needed to expand their knowledge of engineering processes, tools, techniques, language, metrics, and goals., Judy Village, Michael Greig, S. Zolfaghari, F. Salustri & W. P. Neumann (2014) Adapting Engineering Design Tools to Include Human Factors, IIE Transactions on Occupational Ergonomics and Human Factors, 2:1, 1-14, DOI:10.1080/21577323.2014.905884
Adapting the failure modes effect analysis (FMEA) for early detection of human factors concerns
Adapting the failure modes effect analysis (FMEA) for early detection of human factors concerns
As one of many initiatives underway in a collaborative action research project with a large manufacturer, this paper presents the development of a "human factors" failure modes effect analysis (HF-FMEA). FMEA is an engineering reliability tool that helps define, identify, prioritize and eliminate known or potential failures of a system, design or manufacturing assembly process, generally to optimize quality or systems safety for consumers. The goal of the HF-FMEA is to detect and minimize risk of injury for the operator who will assemble products, prior to design of an assembly line. Scoring procedures for "severity", "occurrence" and "detection" from a HF perspective are presented with examples. Embedding the HF-FMEA into software templates, and structuring a process for support and integration helps ensure its continued use. The process may be useful for other organizations with hand-intensive assemblies to optimize worker health together with assembly quality.
Adaptive spatial filter based on similarity indices to preserve the neural information on EEG signals during on-line processing
Adaptive spatial filter based on similarity indices to preserve the neural information on EEG signals during on-line processing
This work presents a new on-line adaptive filter, which is based on a similarity analysis between standard electrode locations, in order to reduce artifacts and common interferences throughout electroencephalography (EEG) signals, but preserving the useful information. Standard deviation and Concordance Correlation Coefficient (CCC) between target electrodes and its correspondent neighbor electrodes are analyzed on sliding windows to select those neighbors that are highly correlated. Afterwards, a model based on CCC is applied to provide higher values of weight to those correlated electrodes with lower similarity to the target electrode. The approach was applied to brain computer-interfaces (BCIs) based on Canonical Correlation Analysis (CCA) to recognize 40 targets of steady-state visual evoked potential (SSVEP), providing an accuracy (ACC) of 86.44 ± 2.81%. In addition, also using this approach, features of low frequency were selected in the pre-processing stage of another BCI to recognize gait planning. In this case, the recognition was significantly (p<0.01) improved for most of the subjects (ACC≥74.79%) , when compared with other BCIs based on Common Spatial Pattern, Filter Bank-Common Spatial Pattern, and Riemannian Geometry. Keywords: artifact reduction; brain-computer interface; EEG; EOG; Laplacian; spatial filter; feature selection; gait planning; SSVEP, Delisle-Rodriguez, D., Villa-Parra, A., Bastos-Filho, T., López-Delis, A., Frizera-Neto, A., Krishnan, S., & Rocon, E. (2017). Adaptive Spatial Filter Based on Similarity Indices to Preserve the Neural Information on EEG Signals during On-Line Processing. Sensors, 17(12), 2725., (This article belongs to the Special Issue Biomedical Sensors and Systems 2017)
Advancing biomimetic materials through ISO standards
Advancing biomimetic materials through ISO standards
This paper discusses the challenges and opportunities of developing standards for biomimetic materials, based on the authors experience with International Organization for Standardization (ISO)/Technical Committee 266 Biomimetics. With the expansion of global trade, international standards are increasingly called on to protect the interests of consumers, improve business productivity and facilitate trade. In the past, standards typically addressed form/fit/function specifications and were associated with mature industries. Recently some ISO standards are focusing on processes, quality and consistency, which can support advances in emerging fields. ISO has the potential to advance biomimetic materials and biomimetics in general by developing and promoting frameworks that reflect the evolving nature of biomimetics., Hoeller, N., & Salustri, F. A. (2016). Dvancing biomimetic materials through ISO standards. Bioinspired, Biomimetic and Nanobiomaterials, 5(4), 171-175.
Age Discrimination and Early Retirement Policies: A Comparison of Labor Market Regulation in Canada and the United States
Age Discrimination and Early Retirement Policies: A Comparison of Labor Market Regulation in Canada and the United States
As public policy issues, mandatory retirement and age discrimination are approached differently in Canada and the United States. TIle legal frameworks, enforcement procedures, and judicial decisions are distinct in the two jurisdictions. The United States, unlike Canada, has specific legislation to protect the rights of older workers, and has a centralized enforcement system. The differences between the two countries are accounted for by the greater emphasis on individual rights in the United States and on communitariarnsm in Canada. The different policy choices of each society highlight the tensions inherent in North American labor markets. The United States seems to be in a better position to shift toward a labor-management policy which encourages older workers to remain in the workforce., Journal of Aging & Social Policy, Vol. 7(1) 1995