Going Wi-Fi in Canada: Municipal, and Community Initiatives

TL;DR: Urban community Wi-Fi in Canada is at a nascent stage; active non-profit groups through dedicated volunteers, support the development or deployment ofWi-Fi services in community spaces throughout their regions.

About: This article is published in Government Information Quarterly.The article was published on 2006-01-01 and is currently open access. It has received 46 citations till now. The article focuses on the topics: Community economic development & Government.

Summary

1. INTRODUCTION

• Over the past decade, direct imaging surveys for extrasolar planets have discovered a small number of planetary-mass companions (hereafter called PMCs; 20 MJup) at 50 AU orbital radii from young stars in nearby star-forming regions.
• These wide-separation PMCs pose a significant challenge to existing models of star and planet formation.
• These results indicate that accretion disks could be common; the authors return to this topic in their discussion of the companion to FW Tau.
• In Section 3, the authors describe their new observations and how they derived the properties of each candidate.

2.1. Candidate Wide PMCs

• Coronagraphic adaptive optics (AO) imaging survey of young southern stars.
• Hα filter, indicating that it had significant Hα emission.
• The authors will revisit this identification in Section 4.3.

2.2. Past Observations

• Many of the candidate companions in their sample were initially (or also) identified by other observing programs, as were several confirmed PMCs that the authors are also studying.
• The authors therefore have adopted uncertainties of 30 mas for their projected separations and the corresponding subtended angle for their P.A.s.
• More generally, the authors note that many observations seem to base their uncertainties on the scatter in their measurements, without considering systematic errors.
• Furthermore, due to the uncertain plate scale, all projected separations are given a minimum fractional uncertainty of 10−3.
• Finally, due to anisoplanatism and variability of the host stars, all contrast ratios are given a minimum uncertainty of 0.05 mag.

2.3. Properties of the Host Stars

• The authors obtained photometric data for the host stars of each candidate from publicly available all-sky surveys.
• The optical r ′ magnitudes for most host stars were taken from the 14th Carlsberg Meridianal Catalog (CMC14; Evans et al. 2002).
• L′ colors agreed to within 0.2 mag, with a scatter of 0.2 mag; similar offsets were seen for disk-bearing and disk-free BDs, indicating that infrared excesses do not bias this relation.
• Where available, the authors adopt proper motions for each star that were reported in the UCAC3 catalog (Zacharias 2010).
• The star HD 27659 falls outside the temperature range spanned by those models, so the authors instead used the models of Siess et al. (2000).

3.1. High-resolution Imaging Observations and Data Analysis

• Most of their high-resolution imaging observations were obtained at Keck Observatory using the Keck-II 10m telescope and NIRC2, its facility AO imager.
• All of the primary stars are brighter than R = 15, so the authors observed them with natural guide star AO at both Keck and Palomar.
• The authors summarize the salient details for these observations in Table 3 and also refer readers to the Keck Observatory Archive,9 which now hosts all NIRC2 data after an 18-month proprietary period.
• The data analysis follows the same prescription as described in Kraus et al. (2008).

3.2. Candidate Properties

• Young stars are intrinsically variable due to several phenomena (i.e., spots, accretion, and variable extinction), so the conversion of contrasts into magnitudes and colors is subject to systematic uncertainties.
• Furthermore, the precision of AO photometry is fundamentally limited by anisoplanatism (e.g., Steinbring et al. 2002), especially for relatively faint targets that were observed with modest Strehl ratios.
• The authors measured the relative motion of each object with a weighted linear fit to compute (μrel,α, μrel,δ).
• Due to the precise and accurate calibration of NIRC2 astrometry (e.g., Yelda et al. 2010), then any fit with multiple NIRC2 points (including those of the three bona fide companions) is effectively dominated by the NIRC2 measurements.
• The authors will discuss their estimates for the companion masses in more detail in Section 4 and list the mass ranges in Table 4.

4.1. Three PMCs to Young Stars

• As the authors summarized in Table 4, three of the candidate companions in their sample are comoving with their host stars.
• All were previously reported in the literature as candidate binary companions, but have been neglected for the past decade.
• Based on the two-point correlation function in unbound associations like these regions (Kraus & Hillenbrand 2008), the probability of chance alignment with an unbound association member within <3′′ is small (<1 chance alignment, including stellar-mass companions, per 104 members) and hence these objects represent a population of bound companions near or within the planetary-mass regime.

4.1.1. FW Tau b

• Given the unresolved system spectral type of M4 (Briceno et al. 1993), models suggest individual masses of 0.28 ± 0.05 M for each component.
• HST images clearly show the characteristic dark lane seen for higher-mass edgeon disks, indicating that at least some substellar edge-on disk systems follow this morphology.

4.1.2. ROXs 42B b

• ROXs 42B AB is a little-studied member of the Ophiuchus complex, located ∼2◦ east of its core.
• It has been neglected in the subsequent literature, so the authors observed the system in 2011 and 2012 to confirm its existence (Figure 2, left) and test for common proper motion (Figure 2, right).
• Given its bound nature and apparently planetary mass, the authors hereafter denote the companion (with some regret regarding the nomenclature) as “ROXs 42B (AB) b” or “ROXs 42B b” for simplicity.
• The nature of this object is less certain; the proximity to the bright primary leaves its colors and astrometry less reliable and the larger expected orbital motion (∼6 mas yr−1 for a circular face-on orbit) is a significant fraction of the absolute proper motion of the system.

4.1.3. ROXs 12 b

• ROXs 12 is another neglected member of the Ophiuchus complex, located ∼1◦ south of its core.
• Ratzka et al. (2005) did note a faint candidate companion at a projected separation of ∼1.′′7 (210 AU) in the shift-and-added stack of their speckle interferometry data.
• It subsequently has been neglected in the literature.
• As a bound companion of approximately planetary mass, the authors denote the companion as “ROXs 12 b.”.
• As for FW Tau b, the presence of a disk in the system (determined from the WISE W3 and W4 photometry) could indicate that the authors have observed a binary companion that is obscured by an edge-on disk.

4.2. Unassociated Background Sources

• As the authors show in Figure 5, six of the candidate companions that they have identified have relative motions that are similar to those expected for a non-moving background star.
• In Figure 6, the authors show the relative motions of four more candidates that appear to be moving with absolute motions of similar magnitude as (but in a different direction than) their host stars, indicating that they are likely not as distant as the candidates listed above.
• These sources were discovered (but not individually resolved) by Köhler et al. (2000), who found relative astrometry that is also consistent with the tracks that the authors observe.
• The authors infer that these objects (denoted ScoPMS 42b cc2 and ScoPMS 42b cc3) are a binary system comprised of two similar-mass field dwarfs.
• Finally, there are two additional targets for which the authors cannot determine a proper motion, but which they can classify as unassociated by other criteria.

4.3. Updated Photometry and Astrometry for Known PMCs

• The authors also have observed five known PMCs in order to obtain more or better colors than were available in the literature, as well (A color version of this figure is available in the online journal.) as to extend the time baseline in confirming common proper motion.
• There is only a modest level of agreement with the DUSTY models at MK 8.
• As for the CMDs, the PMCs largely fall along the young sequence.
• It is unlikely that these red colors denote the presence of lower-mass companions.

6. SUMMARY

• The authors have discovered three PMCs in wide orbits around the young stars FW Tau (in Taurus) and ROXs 12 and ROXs 42B (in Ophiuchus).
• Finally, the authors have obtained multicolor JHK′L′ NIR photometry for their three new companions and for five previously identified companions.
• The authors thank the referee for providing a thorough and helpful critique of this paper.
• Finally, this work was supported by a NASA Keck PI Data Award, administered by the NASA Exoplanet Science Institute.
• The Observatory was made possible by the generous financial support of the W. M. Keck Foundation.

Figures

Fig. 4. Age of ISF user respondents.

Fig. 3. Gender of respondents to ISF Survey, April 2005.

Fig. 2. One user’s Pattern Language story constructed through visits to different hotspots.

Fig. 6. Primary uses of ISF services, April 2005.

Fig. 1. Beta version of community portal site for Laïka Café.

Fig. 5. Occupations of ISF user respondents.

Frequently asked questions

Q1. What contributions have the authors mentioned in the paper "Going wi-fi in canada: municipal and community initiatives" ?

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Q2. What are the main factors that have created a more challenging policy environment?

Technological developments that have created a more challenging policy environment include shifts to IP-based technologies, the deployment of fiber-optic technologies, and the increasing prevalence of wireless technologies. 

Q3. What are some of the devices that operate using this portion of spectrum?

A large number of devices, including garage door openers and commercial wireless equipment, operate using this portion of spectrum. 

Q4. What is the main reason why ISF is encouraging its development?

along with other Montreal non-profit groups, is encouraging ISF to continue to develop their mesh networking project, which would permit community groups to exchange information with one another as well as to potentially gain wireless access to commonly-owned Internet bandwidth. 

Q5. Why is open wireless becoming increasingly popular?

open wireless has become increasinglypopular as a last-mile solution for homes and neighborhoods because there is no license fee for the radio spectrum and because all commercial systems use the same standard for wireless transmission, so devices are easily interoperable. 

Q6. What was the role of community networks in the Canadian economy?

As a community owned and controlled service, community networks emphasized the posting of local resources, services, and culture. 

Q7. What are the best-known community wireless groups in the United States?

The best-known community wireless groups are Seattle Wireless, CUWin (inChampaign-Urbana, Illiniois), NYCWireless in New York City, Wireless London (made up of several distinct smaller groups), and Paris Sans-Fil. 

Q8. How many people have accessed the Internet using ISF’s services?

over 10,000 people have active ISF accounts, and internal logs indicatethat just over 8,000 individuals have accessed the Internet using ISF’s services. 

Q9. What is the main reason why ISF is focusing on community Wi-Fi?

Synergies with municipalities might be a powerful incentive to develop diverse community WiFi initiatives where content can go beyond the provision of municipal services to include more targeted local content. 

Q10. What was the main idea behind community nets?

Proponents of community nets also believed that they could contribute to community development and strengthen and revitalize communities through positive and interactive communication between residents and local institutions. 

Q11. What is the common use of mesh networks in Canada?

In Canada, most community wireless projects concentrate on creating wirelesshotspots, while municipal projects use hub-and-spoke systems and sometimes (although rarely) mesh systems. 

Q12. What are the main objectives of the community wireless groups?

Some groups dedicate themselves to opening hotspots, while others are concerned with the social and community aspects of wireless technology. 

Q13. What is the only funding for ISF that has materialized?

despite the interest by government funding agencies for new technical projects, the only public funding for ISF that has materialized has been through its partnership with the Mobile Digital Commons Network. 

Q14. What is the main reason why the community groups have developed?

These groups have developed either independently or out of existing community networks and have focused on the relatively flexible nature of commercially available Wi-Fi technology – that is, the interoperability of devices operating in license-exempt spectrum. 

Q15. What is the common way to organize a network?

While there are numerous potential technical configurations for wireless Internet projects, municipal and community projects tend to organize their networks in one of three ways: as a series of independent or linked hotspots, as a hub-and-spoke system, or as a dynamic mesh. 

Q16. What are the other recent programs that have pursued similar goals?

Other recent federal and provincial programs have pursued related goals (e.g., Industry Canada’s Broadband for Rural and Northern Development (BRAND); the National Satellite Initiative (NSI); Human Resource and Skills Development Canada’s Community Learning Networks; Government On-line; and the SuperNet project in Alberta. 

Q17. What was the purpose of the partnership?

This partnership mandated the creation of new hotspots in locations chosen by artists and the development of the functionality for adding local content and interactive art. 

Q18. What is the robust and flexible software for developing community mesh networks?

The most robust and flexible software for developing community mesh networks has been produced by CUWin, the Champaign-Urbana community wireless network (http://www.cuwireless.net/). 

Q19. What is the difference between fixed and open wireless?

Open wireless, which operates on license-exempt radio spectrum, has a much lower signal strength than fixed wireless, and as the license-exempt band fills up, transmission speeds can diminish. 

Q20. What is the local management software for a linksys router?

The local management software can be installed on a LinkSys WRTg wireless Internet router, and the authorization server needs to be run from a dedicated server. 

Q21. What was the first time the government invested in a municipal fiber-optic network backbone?

In 1999, the government invested in a municipal fiber-optic network backbone, but it took until 2001 before an appropriate last-mile solution (in this case wireless) was found.