Research

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  • 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
    Web-Enabled Spatial Decision Analysis Using Ordered Weighted Averaging (OWA)
    Web-Enabled Spatial Decision Analysis Using Ordered Weighted Averaging (OWA)
    This paper presents a spatial decision support tool that implements the Ordered Weighted Averaging (OWA) method. OWA is a family of multicriteria evaluation operators characterised by two sets of weights: criterion importance weights and order weights. We propose a highly interactive way of choosing, modifying, and fine-tuning the decision strategy defined by the order weights. This exploratory approach to OWA is supported by a graphical representation of the operator’s behaviour in terms of decision risk and tradeoff/dispersion between criteria. Our prototype implementation is based on the CommonGIS software, and thus, Webenabled and working with vector data. We successfully demonstrate online, exploratory support of spatial decision strategies using a data set of skiing resorts in Wallis, Switzerland.
    Web-based Spatial Decision Support: Status and Research Directions
    Web-based Spatial Decision Support: Status and Research Directions
    This paper summarizes research on Web-based spatial decision support systems (WebSDSS). The review distinguishes early server-side from more recent client-side applications. A third category of WebSDSS focusing on spatial decision support in public participation is typically implemented as a mixed client/server-based system. Conclusions drawn from previous work include the need for systematic user studies of WebSDSS, and the adoption of interoperable architectures for distributed spatial decision support. Furthermore, a conceptual framework is proposed to facilitate further studies of WebSDSS methods.
    Welfare effects of preferential trade agreements under optimal tariffs
    Welfare effects of preferential trade agreements under optimal tariffs
    In a three country model with endogenous tariffs, this paper evaluates and contrasts the welfare effects of free trade agreements (FTAs) and customs unions (CUs) — the two most commonly occurring preferential trade agreements (PTAs). We show that if the external tariff of a PTA is not too high, it benefits both members and non-members. We also highlight the implications of a key (but commonly ignored) distinction between the two types of PTAs: while an FTA member can form an another (independent) FTA with an existing non-member, a CU member cannot. Under a pair of independent bilateral FTAs, the common member’s welfare is higher than that under free trade. Furthermore, if the common member is relatively efficient compared to the other two countries, such a ‘hub and spoke’ pattern of FTAs can yield higher global welfare than free trade. By contrast, such an outcome is never possible under a CU., Also available for download here: http://mpra.ub.uni-muenchen.de/17562/
    What If There Is No Killer Application? An Exploration of a User-Centric Perspective on Broadband
    What If There Is No Killer Application? An Exploration of a User-Centric Perspective on Broadband
    This paper explores user and provider experiences with broadband networks. Drawing on data from an early broadband trial and from recent studies of consumer broadband usage, the validity of the commonly held view that widespread adoption of broadband is dependent upon the development of a killer application is challenged. It is argued that access to broadband can be valuable for users without the provision of a killer application and that the dynamics of broadband development are shifting. As more users become content creators and distributors and as it becomes easier for consumers to establish broadband networks without help from traditional providers, the existing relationships within the broadband industry will change. Broadband researchers and stakeholders in the development of broadband networks are encouraged to explore and understand the implications of these changes, recognizing that there is much to be learned about deploying broadband in ways that will create the broad societal benefits promised by its promoters., Preprint of an article later published as: Middleton, C. A. (2003). What If There Is No Killer Application? An Exploration of a User-Centric Perspective on Broadband. Journal of Information Technology, 18(4), 231-246. Publisher URL: http://www.informaworld.com/openurl?genre=article&issn=0268%2d3962&volume=18&issue=4&spage=231
    What Makes Journalism “Excellent”? Criteria Identified by Judges in Two Leading Awards Programs
    What Makes Journalism “Excellent”? Criteria Identified by Judges in Two Leading Awards Programs
    What does “excellence” mean in journalism? The literature reveals no universally agreed set of standards, and awards guidelines are often unclear. We interviewed judges in two leading Canadian print journalism awards programs, using a sequence of open-ended and ranking questions to probe their criteria of excellence in a way calculated to elicit not just the standards they felt should be applied but the standards they actually did apply. Judges mentioned a wide variety of criteria, including the social importance and impact of works of journalism. But only two values were affirmed consistently: writing style and reporting rigour., Shapiro, I., Albanese, P., & Doyle, L. (2006). What Makes Journalism “Excellent”? Criteria Identified by Judges in Two Leading Awards Program, Canadian Journal of Communication, 31(2), 425-445. Retrieved from http://www.cjc-online.ca/index.php/journal/article/view/1743