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Documents authored by McKenzie, Grant


Document
Platial k-Anonymity: Improving Location Anonymity Through Temporal Popularity Signatures

Authors: Grant McKenzie and Hongyu Zhang

Published in: LIPIcs, Volume 277, 12th International Conference on Geographic Information Science (GIScience 2023)


Abstract
While it is increasingly necessary in today’s digital society, sharing personal location information comes at a cost. Sharing one’s precise place of interest, e.g., Compass Coffee, enables a range of location-based services, but substantially reduces the individual’s privacy. Methods have been developed to obfuscate and anonymize location data while still maintaining a degree of utility. One such approach, spatial k-anonymity, aims to ensure an individual’s level of anonymity by reporting their location as a set of k potential locations rather than their actual location alone. Larger values of k increase spatial anonymity while decreasing the utility of the location information. Typical examples of spatial k-anonymized datasets present elements as simple geographic points with no attributes or contextual information. In this work, we demonstrate that the addition of publicly available contextual data can significantly reduce the anonymity of a k-anonymized dataset. Through the analysis of place type temporal visitation patterns, hours of operation, and popularity values, one’s anonymity can be decreased by more than 50 percent. We propose a platial k-anonymity approach that leverages a combination of temporal popularity signatures and reports the amount that k must increase in order to maintain a certain level of anonymity. Finally, a method for reporting platial k-anonymous regions is presented and the implications of our methods are discussed.

Cite as

Grant McKenzie and Hongyu Zhang. Platial k-Anonymity: Improving Location Anonymity Through Temporal Popularity Signatures. In 12th International Conference on Geographic Information Science (GIScience 2023). Leibniz International Proceedings in Informatics (LIPIcs), Volume 277, pp. 9:1-9:15, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2023)


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@InProceedings{mckenzie_et_al:LIPIcs.GIScience.2023.9,
  author =	{McKenzie, Grant and Zhang, Hongyu},
  title =	{{Platial k-Anonymity: Improving Location Anonymity Through Temporal Popularity Signatures}},
  booktitle =	{12th International Conference on Geographic Information Science (GIScience 2023)},
  pages =	{9:1--9:15},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-288-4},
  ISSN =	{1868-8969},
  year =	{2023},
  volume =	{277},
  editor =	{Beecham, Roger and Long, Jed A. and Smith, Dianna and Zhao, Qunshan and Wise, Sarah},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.GIScience.2023.9},
  URN =		{urn:nbn:de:0030-drops-189045},
  doi =		{10.4230/LIPIcs.GIScience.2023.9},
  annote =	{Keywords: location anonymity, location privacy, geoprivacy, place, temporal, geosocial}
}
Document
Short Paper
When Everything Is "Nearby": How Airbnb Listings in New York City Exaggerate Proximity (Short Paper)

Authors: Mikael Brunila, Priyanka Verma, and Grant McKenzie

Published in: LIPIcs, Volume 277, 12th International Conference on Geographic Information Science (GIScience 2023)


Abstract
In recent years, the emergence and rapid growth of short-term rental (STR) markets has exerted considerable influence on real estate in most large cities across the world. Central location and transit access are two primary factors associated with the prevalence and expansion of STRs, including Airbnbs. Nevertheless, perhaps due to methodological challenges, no research has addressed how location and proximity are represented in the titles and descriptions of STRs. In this paper, we introduce a new methodological pipeline to extract spatial relations from text and show that expressions of distance in STR listings can indeed be quantified and measured against real-world distances. We then comparatively analyze Airbnb reviews (written by guests) and listings (written by hosts) from New York City in order to demonstrate systematically how listings exaggerate proximity compared to reviews. Moreover, we discover spatial patterns to these differences that warrant further investigation.

Cite as

Mikael Brunila, Priyanka Verma, and Grant McKenzie. When Everything Is "Nearby": How Airbnb Listings in New York City Exaggerate Proximity (Short Paper). In 12th International Conference on Geographic Information Science (GIScience 2023). Leibniz International Proceedings in Informatics (LIPIcs), Volume 277, pp. 16:1-16:8, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2023)


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@InProceedings{brunila_et_al:LIPIcs.GIScience.2023.16,
  author =	{Brunila, Mikael and Verma, Priyanka and McKenzie, Grant},
  title =	{{When Everything Is "Nearby": How Airbnb Listings in New York City Exaggerate Proximity}},
  booktitle =	{12th International Conference on Geographic Information Science (GIScience 2023)},
  pages =	{16:1--16:8},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-288-4},
  ISSN =	{1868-8969},
  year =	{2023},
  volume =	{277},
  editor =	{Beecham, Roger and Long, Jed A. and Smith, Dianna and Zhao, Qunshan and Wise, Sarah},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.GIScience.2023.16},
  URN =		{urn:nbn:de:0030-drops-189117},
  doi =		{10.4230/LIPIcs.GIScience.2023.16},
  annote =	{Keywords: spatial proximity, distance estimation, information extraction, named entity recognition, short-term rentals}
}
Document
Short Paper
Mobility Vitality: Assessing Neighborhood Similarity Through Transportation Patterns In New York City (Short Paper)

Authors: Dan Qiang and Grant McKenzie

Published in: LIPIcs, Volume 277, 12th International Conference on Geographic Information Science (GIScience 2023)


Abstract
Though numerous studies have examined human mobility within an urban environment, few have explored the concept of urban vitality purely through the lens of urban transportation. Given the importance of different modes of transportation within a city, such analysis is necessary. In this short paper, we introduce the novel concept of mobility vitality by integrating human mobility and urban vitality, offering a multilayered framework to assess the degree of transportation and mobility within and between regions. The mobility patterns of three transportation modes, namely subway, taxicab, and bike-share, are first examined independently. These patterns are then aggregated to form the composite measure of static mobility vitality. Through this measure, we evaluate similarities between neighborhoods. Our results observed significant spatial differences in the travel patterns of three transportation modes on weekdays and weekends. Moreover, neighborhoods with high static mobility vitality have relatively similar mobility patterns. Ultimately, this approach aims to find neighborhoods with imbalanced transportation infrastructure or inadequate public.

Cite as

Dan Qiang and Grant McKenzie. Mobility Vitality: Assessing Neighborhood Similarity Through Transportation Patterns In New York City (Short Paper). In 12th International Conference on Geographic Information Science (GIScience 2023). Leibniz International Proceedings in Informatics (LIPIcs), Volume 277, pp. 61:1-61:6, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2023)


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@InProceedings{qiang_et_al:LIPIcs.GIScience.2023.61,
  author =	{Qiang, Dan and McKenzie, Grant},
  title =	{{Mobility Vitality: Assessing Neighborhood Similarity Through Transportation Patterns In New York City}},
  booktitle =	{12th International Conference on Geographic Information Science (GIScience 2023)},
  pages =	{61:1--61:6},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-288-4},
  ISSN =	{1868-8969},
  year =	{2023},
  volume =	{277},
  editor =	{Beecham, Roger and Long, Jed A. and Smith, Dianna and Zhao, Qunshan and Wise, Sarah},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.GIScience.2023.61},
  URN =		{urn:nbn:de:0030-drops-189566},
  doi =		{10.4230/LIPIcs.GIScience.2023.61},
  annote =	{Keywords: mobility vitality, mobility similarity, transportation, bike-sharing, taxi, subway, New York City}
}
Document
Short Paper
Docked vs. Dockless Bike-sharing: Contrasting Spatiotemporal Patterns (Short Paper)

Authors: Grant McKenzie

Published in: LIPIcs, Volume 114, 10th International Conference on Geographic Information Science (GIScience 2018)


Abstract
U.S. urban centers are currently experiencing explosive growth in commercial dockless bike-sharing services. Tens of thousands of bikes have shown up across the country in recent months providing limited time for municipal governments to set regulations or assess their impact on government-funded dock-based bike-sharing programs. Washington, D.C. offers an unprecedented opportunity to examine the activity patterns of both docked and dockless bike-sharing services given the history of bike-sharing in the city and the recent availability of dockless bike data. This work presents an exploratory step in understanding how dockless bike-sharing services are being used within a city and the ways in which the activity patterns differ from traditional dock station-based programs.

Cite as

Grant McKenzie. Docked vs. Dockless Bike-sharing: Contrasting Spatiotemporal Patterns (Short Paper). In 10th International Conference on Geographic Information Science (GIScience 2018). Leibniz International Proceedings in Informatics (LIPIcs), Volume 114, pp. 46:1-46:7, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2018)


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@InProceedings{mckenzie:LIPIcs.GISCIENCE.2018.46,
  author =	{McKenzie, Grant},
  title =	{{Docked vs. Dockless Bike-sharing: Contrasting Spatiotemporal Patterns}},
  booktitle =	{10th International Conference on Geographic Information Science (GIScience 2018)},
  pages =	{46:1--46:7},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-083-5},
  ISSN =	{1868-8969},
  year =	{2018},
  volume =	{114},
  editor =	{Winter, Stephan and Griffin, Amy and Sester, Monika},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.GISCIENCE.2018.46},
  URN =		{urn:nbn:de:0030-drops-93746},
  doi =		{10.4230/LIPIcs.GISCIENCE.2018.46},
  annote =	{Keywords: bike-share, dockless, bicycle, transportation, spatiotemporal patterns}
}
Document
Short Paper
OpenPOI: An Open Place of Interest Platform (Short Paper)

Authors: Grant McKenzie and Krzysztof Janowicz

Published in: LIPIcs, Volume 114, 10th International Conference on Geographic Information Science (GIScience 2018)


Abstract
Places of Interest (POI) are a principal component of how human behavior is captured in today's geographic information. Increasingly, access to POI datasets are being restricted - even silo-ed - for commercial use, with vendors often impeding access to the very users that contribute the data. Open mapping platforms such as OpenStreetMap (OSM) offer access to a plethora of geospatial data though they can be limited in the attribute resolution or range of information associated with the data. Nuanced descriptive information associated with POI, e.g., ambience, are not captured by such platforms. Furthermore, interactions with a POI, such as checking in, or recommending a menu item, are inherently place-based concepts. Many of these interactions occur with high temporal volatility that involves frequent interaction with a platform, arguably inappropriate for the "changeset" model adopted by OSM and related datasets. In this short paper we propose OpenPOI, an open platform for storing, serving, and interacting with places of interests and the activities they afford.

Cite as

Grant McKenzie and Krzysztof Janowicz. OpenPOI: An Open Place of Interest Platform (Short Paper). In 10th International Conference on Geographic Information Science (GIScience 2018). Leibniz International Proceedings in Informatics (LIPIcs), Volume 114, pp. 47:1-47:6, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2018)


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@InProceedings{mckenzie_et_al:LIPIcs.GISCIENCE.2018.47,
  author =	{McKenzie, Grant and Janowicz, Krzysztof},
  title =	{{OpenPOI: An Open Place of Interest Platform}},
  booktitle =	{10th International Conference on Geographic Information Science (GIScience 2018)},
  pages =	{47:1--47:6},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-083-5},
  ISSN =	{1868-8969},
  year =	{2018},
  volume =	{114},
  editor =	{Winter, Stephan and Griffin, Amy and Sester, Monika},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.GISCIENCE.2018.47},
  URN =		{urn:nbn:de:0030-drops-93752},
  doi =		{10.4230/LIPIcs.GISCIENCE.2018.47},
  annote =	{Keywords: place, point of interest, open data, gazetteer, check-in}
}
Document
Juxtaposing Thematic Regions Derived from Spatial and Platial User-Generated Content

Authors: Grant McKenzie and Benjamin Adams

Published in: LIPIcs, Volume 86, 13th International Conference on Spatial Information Theory (COSIT 2017)


Abstract
Typical approaches to defining regions, districts or neighborhoods within a city often focus on place instances of a similar type that are grouped together. For example, most cities have at least one bar district defined as such by the clustering of bars within a few city blocks. In reality, it is not the presence of spatial locations labeled as bars that contribute to a bar region, but rather the popularity of the bars themselves. Following the principle that places, and by extension, place-type regions exist via the people that have given space meaning, we explore user-contributed content as a way of extracting this meaning. Kernel density estimation models of place-based social check-ins are compared to spatially tagged social posts with the goal of identifying thematic regions within the city of Los Angeles, CA. Dynamic human activity patterns, represented as temporal signatures, are included in this analysis to demonstrate how regions change over time.

Cite as

Grant McKenzie and Benjamin Adams. Juxtaposing Thematic Regions Derived from Spatial and Platial User-Generated Content. In 13th International Conference on Spatial Information Theory (COSIT 2017). Leibniz International Proceedings in Informatics (LIPIcs), Volume 86, pp. 20:1-20:14, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2017)


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@InProceedings{mckenzie_et_al:LIPIcs.COSIT.2017.20,
  author =	{McKenzie, Grant and Adams, Benjamin},
  title =	{{Juxtaposing Thematic Regions Derived from Spatial and Platial User-Generated Content}},
  booktitle =	{13th International Conference on Spatial Information Theory (COSIT 2017)},
  pages =	{20:1--20:14},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-043-9},
  ISSN =	{1868-8969},
  year =	{2017},
  volume =	{86},
  editor =	{Clementini, Eliseo and Donnelly, Maureen and Yuan, May and Kray, Christian and Fogliaroni, Paolo and Ballatore, Andrea},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.COSIT.2017.20},
  URN =		{urn:nbn:de:0030-drops-77476},
  doi =		{10.4230/LIPIcs.COSIT.2017.20},
  annote =	{Keywords: place type, thematic region, temporal signature, topic modeling, user-generated content}
}
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