Research

  • 126
  • 50
  • Virtual Tools for Assessing Human and Organisational Factors in Production System Design
    Virtual Tools for Assessing Human and Organisational Factors in Production System Design
    This paper describes two approaches for integrating human factors into discrete event simulations of production systems. In the first, biomechanical loading information was integrated with a simulation model in a car dismantling operation. In the second study, the productivity sensitivity of three systems with varying parallelisation was tested with respect to a) allowing operators to take breaks ‘as desired’, and b) having ‘reduced capacity’ operators at work. Both methods provided insight into design options that gave superior performance with improved ergonomics. Such ‘virtual ergonomics’ approaches can help establish boundary crossing discussions to support ergonomics application in early design stages., For a more in-depth look on this subject, please see: Kazmierczak, K., Neumann, W.P. and Winkel, J., 2007. A case study of serial-flow car disassembly: ergonomics, productivity, and potential system performance. Human Factors and Ergonomics in Manufacturing, 17(4): 331-351. DOI: 10.1002/hfm.20078 Neumann, W.P. and Medbo, P., 2009. Integrating human factors into discrete event simulations of parallel and serial flow strategies. Production Planning & Control, 20(1): 3-16. DOI: 10.1080/09537280802601444 Perez, J. and Neumann, W.P., 2010. The Use of Virtual Human Factors Tools in Industry – A Workshop Investigation, Ryerson University, Toronto.http://digitalcommons.ryerson.ca/ie/1/
    Virtual identity: applying narrative theory to online character development
    Virtual identity: applying narrative theory to online character development
    This paper will explore the realm of virtual identity within the context of the online virtual world, Second Life. The creation of virtual identities involves the complex process of constructing an online self-presentation. With the prevalence of online forums and virtual reality, ordinary people are crafting identities online and digressing from their actual identities in real life. In order to explain this phenomenon, I draw on narrative theory’s conceptualization of character in order to understand how people craft online identities., Yumansky, S. (2008, Spring). Virtual identity: applying narrative theory to online character development. Stream: Culture/Politics/Technology, 1(1). Retrieved from http://journals.sfu.ca/stream/index.php/stream/article/view/4/4
    Visualization of Apoptotic Cells using Scanning Acoustic Microscopy and High Frequency Ultrasound
    Visualization of Apoptotic Cells using Scanning Acoustic Microscopy and High Frequency Ultrasound
    Online version of a conference paper originally published as: Visualization of Apoptotic Cells using Scanning Acoustic Microscopy and high frequency ultrasound, S. Brand*, G. J. Czarnota, E. C. Weiss, R. Lemor and M.C.Kolios, In Proceedings of the 2005 IEEE International Ultrasonics Symposium, Volume 2, Page(s):882 - 885 Publisher URL: http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=1602991
    Visualization of Lake Mead Surface Area Changes from 1972 to 2009
    Visualization of Lake Mead Surface Area Changes from 1972 to 2009
    For most of the last decade, the south-western portion of the United States has experienced a severe and enduring drought. This has caused serious concerns about water supply and management in the region. In this research, 30 orthorectified Landsat satellite images from the United States Geological Service (USGS) Earth Explorer archive were analyzed for the 1972 to 2009 period. The images encompassed Lake Mead (a major reservoir in this region) and were examined for changes in water surface area. Decadal lake area minimums/maximums were achieved in 1972/1979, 1981/1988, 1991/1998, and 2009/2000. The minimum lake area extent occurred in 2009 (356.4 km2), while the maximum occurred in 1998 (590.6 km2). Variable trends in water level and lake area were observed throughout the analysis period, however progressively lower values were observed since 2000. The Landsat derived lake areas show a very strong relationship with actual measured water levels at the Hoover Dam. Yearly water level variations at the dam vary minimally from the satellite derived estimates. A complete (yearly) record of satellite images may have helped to reduce the slight deviations in the time series., Forsythe, K. W., Schatz, B., Swales, S. J., Ferrato, L., & Atkinson, D. M. (2012). Visualization of lake mead surface area changes from 1972 to 2009. ISPRS International Journal of Geo-Information, 1(3), 108-119. doi:10.3390/ijgi1020108
    Visualizing Information in the Early Stages of Engineering Design
    Visualizing Information in the Early Stages of Engineering Design
    The early stages of engineering design are the most crucial for successful product development, yet they are not well supported with computer tools compared to other, downstream stages. This paper will discuss recent efforts by the authors to create visual representations of, and tools for, the non geometric, qualitative information typical in the early stages of engineering design. It appears evident that there is tremendous opportunity to improve the capacity of designers to think both critically and creatively through diagramming in early design, but the field is still embryonic and much work remains to be done., Salustri, F. A., Eng, N. L., & Weerasinghe, J. S. (2008). Visualizing Information in the Early Stages of Engineering Design. Computer-Aided Design and Applications, 5((1-4)), 1-18. doi:10.3722/cadaps.2008.xxx-yyy
    Wait times for publicly funded addiction and problem gambling treatment agencies in Ontario, Canada
    Wait times for publicly funded addiction and problem gambling treatment agencies in Ontario, Canada
    Background This study describes the definitions of wait times and intake processes used by drug and problem gambling treatment agencies in Ontario, Canada, as well as the various strategies employed to ameliorate client backlog. Methods An online survey was developed and distributed to 203 publicly-funded, provincial substance use and problem gambling treatment agencies from June to August, 2011. All aspects of the intake process were covered in the survey. Results Based on 139 responses, six different wait time periods were identified. Additional analyses were completed by type of service offered. Suggestions for effective interventions to shorten wait times and recommendations for future research are provided. Conclusion The results of this study highlight a need for standardized definitions of wait times across substance use and problem gambling treatment services., Pascoe, R. V., Rush, B., & Rotondi, N. K. (2013). Wait times for publicly funded addiction and problem gambling treatment agencies in ontario, canada. BMC Health Services Research, 13, 483. doi:10.1186/1472-6963-13-483
    Wake-model effects on induced drag prediction of staggered boxwings
    Wake-model effects on induced drag prediction of staggered boxwings
    For staggered boxwings the predictions of induced drag that rely on common potential-flow methods can be of limited accuracy. For example, linear, freestream-fixed wake models cannot resolve effects related to wake deflection and roll-up, which can have significant affects on the induced drag projection of these systems. The present work investigates the principle impact of wake modelling on the accuracy of induced drag prediction of boxwings with stagger. The study compares induced drag predictions of a higher-order potential-flow method that uses fixed and relaxed-wake models, and of an Euler-flow method. Positive-staggered systems at positive angles of attack are found to be particularly prone to higher-order wake effects due to vertical contraction of wakes trajectories, which results in smaller effective height-to-span ratios than compared with negative stagger and thus closer interactions between trailing wakes and lifting surfaces. Therefore, when trying to predict induced drag of positive staggered boxwings, only a potential-flow method with a fully relaxed-wake model will provide the high-degree of accuracy that rivals that of an Euler method while being computationally significantly more efficient. Keywords: wake-model; boxwing; induced drag; potential-flow theory, Schirra, J., Bissonnette, W., & Bramesfeld, G. (2018). Wake-Model Effects on Induced Drag Prediction of Staggered Boxwings. Aerospace, 5(1), 14., (This article belongs to the Collection Feature Papers in Aerospace)
    Want to understand local news? Make a map
    Want to understand local news? Make a map
    Critics have suggested that scholars seeking to advance journalism studies must adopt a more multidisciplinary approach to research, one that looks beyond the strict confines of sociology, history, language studies, political science, or cultural analysis. This paper argues that the geography of news coverage is a valuable starting point for scholars who wish to understand what local news gets reported, why and how it gets reported, and the potential consequences of such news coverage. The work of the Local News Research Project at Ryerson University is introduced to illustrate how maps that reveal the geospatial aspects of local news can foster multidisciplinary investigations that push researchers beyond the traditional silos of journalism scholarship., Lindgren, April and Christina Wong. 2012. Want to understand local news?Make a map. Proceedings of the 2012 annual conference of the Canadian Communication Association. Available via: <http://cca.kingsjournalism.com/?p=169>.
    Water-in-water droplets by passive microfluidic flow focusing
    Water-in-water droplets by passive microfluidic flow focusing
    We present a simple microfluidic system that generates water-in-water, aqueous two phase system (ATPS) droplets, by passive flow focusing. ATPS droplet formation is achieved by applying weak hydrostatic pressures, with liquid-filled pipette tips as fluid columns at the inlets, to introduce low speed flows to the flow focusing junction. To control the size of the droplets, we systematically vary the interfacial tension and viscosity of the ATPS fluids, and adjust the fluid column height at the fluid inlets. The size of the droplets scales with a power-law of the ratio of viscous stresses in the two ATPS phases. Overall, we find a drop size coefficient of variation (CV; i.e. polydispersity) of about 10 %. We also find that when drops form very close to the flow focusing junction, the drops have CV of less than 1 %. Our droplet generation method is easily scalable: we demonstrate a parallel system that generates droplets simultaneously, and improves the droplet production rate by up to one order-of-magnitude. Finally, we show the potential application of our system for encapsulating cells in water-in-water emulsions, by encapsulating microparticles and cells. To the best of our knowledge, our microfluidic technique is the first that forms low interfacial tension ATPS droplets without applying external perturbations. We anticipate that this simple approach will find utility in drug and cell delivery applications because of the all-biocompatible nature of the water-in-water ATPS environment., Moon, B., Abbasi, N., Jones, S. G., Hwang, D. K., & Tsai, S. S. (n.d.). Water-in-water droplets by passive microfluidic flow focusing (pp. 1-25, Publication). Toronto, Ontario: Department of Mechanical and Industrial Engineering, Ryerson University., E-mail: dkhwang@ryerson.ca; scott.tsai@ryerson.ca
    Wavelength-Switchable Dissipative Soliton Fiber Laser With a Chirped Fiber Grating Stop-Band Filter
    Wavelength-Switchable Dissipative Soliton Fiber Laser With a Chirped Fiber Grating Stop-Band Filter
    We report a wavelength-switchable single-polarization dissipative soliton (DS) mode-locked fiber laser using a chirped fiber Bragg grating (FBG) for spectral filtering. The chirped FBG, when inserted into the ring cavity, provides a stopband from 1045 nm to 1057 nm, which is used for spectral filtering in this all-normal-dispersion mode-locked Yb-doped fiber laser. The combination of the chirped FBG and the Yb gain profile help the formation of the DS. The laser delivers wavelength-switchable and polarized (28 dB) DS of 6.1 nJ and 29 ps at 1032 nm, and 4.3 nJ and 24 ps at 1068 nm, respectively. To the best of our knowledge, this is the direct proof that a bandpass filter is not indispensible to achieve stable DS in ps fiber lasers., Zhang, L., Feng, Y., & Gu, X. (2013). Wavelength-switchable dissipative soliton fiber laser with a chirped fiber grating stop-band filter. IEEE Photonics Journal, 5(2), 1500506-1500506. doi:10.1109/JPHOT.2013.2252608
    Wealth effects in a cash-in-advance economy
    Wealth effects in a cash-in-advance economy
    This paper examines the monetary growth implications of combining Stockman's cash-in-advance constraint on consumption and capital goods and an endogenous rate of time preference that is an increasing function of real wealth. The cash-in-advance constraint imposes an investment tax that reduces steady state consumption and capital. However, endogenous time preference wealth effects link the real and monetary sectors to yield a Mundell-Tobin effect. Cash-in-advance constraint effects dominate endogenous time preference wealth effects so that monetary growth reduces steady state capital and consumption., Also available for download here: http://ideas.repec.org/a/ebl/ecbull/v5y2003i2p1-7.html