Location-Aware Information Delivery with ComMotion

Posted: July 23rd, 2006 | No Comments »

Marmasse, N. and Schmandt, C. 2000. Location-Aware Information Delivery with ComMotion. In Proceedings of the 2nd international Symposium on Handheld and Ubiquitous Computing (Bristol, UK, September 25 – 27, 2000). P. J. Thomas and H. Gellersen, Eds. Lecture Notes In Computer Science, vol. 1927. Springer-Verlag, London, 157-171.

ComMotion is a location-aware computing environment which links personal information to locations. Its uses GPS position sensing to gradually learn about the locations of the users’ daily life based on travel patterns. The authors use a simple learning algorithm to exploit the GPS signals loss to detect building. When the GPS signal was lost and then later re–acquired within a certain radius, comMotion considered this to be indicative of a building. This approach avoided false detection of buildings when passing through urban canyons or suffering from hardware issues such as battery loss.

Unfortuantally, the evalutation of the system was only done with 4 people. Therefore the feedback on location precision is rather weak:

Precision and Alert Timing. GPS data is intentionally imprecise –when the user evaluation was done, accuracy was within 100 metres. For this application, exact position information is not required. When two different virtual locations are physically within meters of each other, however, due to the inaccuracy of the position data, one location is identified and not the other –that is, location shadowing. This can be solved by clustering the virtual locations and providing alerts for all the locations within the cluster. The lack of precision of position data also strongly affects the alert timing and auditory cues were sometimes given too late. Loss of GPS signal due to shadowing by tall buildings was also experienced.

Relation to my thesis: The authors acknowledge that location accuracy and reliability must be taken into account for the design of location-aware application. They integrate the signal loses to make sense of the space. They also mention the importance of the granularity of the location information. However, the feedback of only 4 people is really limiting to evaluate if the learning algorithm and the design. This work is very much related to Learning Significant Locations and Predicting User Movement with GPS.

Accuracy Attribute in Latest Google Maps API

Posted: July 21st, 2006 | No Comments »

The Google Maps API v2.60 adds, among other features, an accuracy attribute for the geocoder, that is how accurately the address could be geocoded. For example, the geocoder returns 7 (intersection level accuracy) for the address “Haight and Ashbury St, San Francisco” and 4 (town level accuracy) for “New York City”.

Relation to my thesis: Accuracy is an attribute of location quality. This value could helps defining the granularity of the location information to be displayed matching the data given to the geocoder.

GIS/GPS in Transportation, Real World Experiences

Posted: July 21st, 2006 | 1 Comment »

Guo, Bo, Allen D. Poling, and Mark J. Poppe, 1995. GIS/GPS in Transportation, Real World Experiences. Proceedings of the 15th Annual ESRI User Conference

A paper that summarizes the three types of real world applications of the GIS/GPS technologies

  1. GPS as a Roadway Data Collector
  2. GIS as a Transportation Database Manager
  3. GPS as a Traffic Design Aid

The authors discuss the problems of accuracy and GPS signal reception and the problems in data acquisition and validation.

Location data collected through GPS units have intrinsic random errors that cannot be totally eliminated. To obtain the higher level of accuracy for any receiver requires differential correction, a process of placing a receiver on a known location, called a base station, and using the collected satellite data to adjust GPS positions compute by other receivers at unknown locations during the same time period.
Bad GPS signal reception results in missing data. This has been another major issue.
Due to GPS reception problems mentioned above, it was necessary to collect some attribute information using manual methods in the White House/Washington Mal project.
Some of Lee’s experiences indicate that the most difficult aspects of GIS are not necessary at the technical level, but at the data acquisition and validation level.

Relation to my thesis: Real-world example of the use of geospatial information with the issues of measuring/mapping the physical space. In addition to my other reading in the transportation research.

HawkTour: A Mobile, Context-Aware Tour Guide System

Posted: July 19th, 2006 | No Comments »

Related to the book Local Positioning Systems, Tyler Butler, Santhosh Meleppuram, Xian-He Sun from the Illinois Institute of Technology describe the architecture of HawkTour, a TabletPC-based system, allowing visitors to tour the IIT main campus. Positioning is done by the fusion of GPS for outdoor navigation and Wi-Fi based transliteration for indoors. The project is now called MyWay that uses Segways to tour the Chicago city center.

Relation to my thesis: The architecture of HawkTour has many similarities with CatchBob! (TablePCs, Wi-Fi positioning, SOAP as high-level protocol, …). The description of their system is an inspiration for the formalization of the technical part of my CatchBob! postmortem into a paper.

Precision Indoor/Outdoor Personnel Location Project

Posted: July 19th, 2006 | 1 Comment »

 Research Ppl Images SafeexitEach of indoor location technologies has drawbacks. For example, enhanced GPS is currently unable to achieve the precision required for first responder location. Inertial navigation relies on gyroscopes, which must be frequently realigned. RFID systems only work in buildings where monitoring stations have been preinstalled.

In their Precision Personnel Location Project, a Worcester Polytechnic Institute (WPI) research group has been following a different route, developing a system that employs principles from orthogonal frequency division multiplexing (OFDM), which transmits high-speed data via wired and wireless channels and integrates well in the radio spectrum, along with super-resolution techniques as used in synthetic aperture radar (SAR), which can extract great detail from radar signals.

WPI’s first responder locator system will employ transmitters, to be worn by the first responders, that continuously emit customized OFDM signals. Receivers located on emergency vehicles arrayed around a building will detect and decipher the signals. The receivers will use sophisticated, custom-designed algorithms to determine their distance from the transmitters and, by sorting out a multitude of straight-line and reflected signals, determine the exact location of the transmitters in three-dimensional space.

Relation to my thesis: An indoor positioning approach with radar signals I have not aware off.

Meeting with Paul Verschure

Posted: July 19th, 2006 | No Comments »

Today, I had a meeting with Paul Verschure. Paul is an ICREA Professor at the UPF with a background in cognitive neuroscience and neuroinformatics.

For my interest on the impact of special uncertainty, he advised me to have a closer look at the literature in spatial cognition and more precisely in spatial navigation. Somehow, his suggested to step backward to the first results and literature review I did so far. First I should gain basic understanding of spatial cognition under uncertainty and then suggest implications for design. We talked about the ways the studies are ran in experimental psychology and specifically how to carefully control conditions (manipulating uncertainty) in uncontrolled environments. it is very much possible when the control group and the experimental group are very carefully selected and managed. One challenge is not to fall into the problem of confirmation bias (interpret information according to preconceptions). In my context, I could work on three parameters (e.g. map resolution, abstraction of the data on the map, …) and then measure the performance and/or the learning.

I plan to setup a second experiment in a larger scale uncontrolled environment (because “scale” is one of the 2 most important challenge of ubicomp, next to “context”). Paul was pretty enthusiast about it and saw a lot of potential. It could actually become a real-world framework for multiple experiments (potential at the 22@ area). A scholarship is potentially available for a psychologist to work with me. Moreover, structures such as the Urban Ecology Agency of Barcelona are in deep need of data about people’s mobility and might be interested in getting involved. Such connection would match with my early digging into ABM and transportation research. I also came up some fun basic study that could involve Barcelona taxi drivers using GPS systems . To that, Paul mentioned a study in London that showed that Taxi drivers’ brains ‘grow’ on the job due to the navigating they do (“The posterior hippocampus was also more developed in taxi drivers who had been in the career for 40 years than in those who had been driving for a shorter period.”).

On the side, Paul introduced me to Bayesian Inference and how users have multiple sources of information (in the context of spatial uncertainty).

Relation to my thesis: facing experimental psychology and first thoughts on the resources available for a second experiment. I will dig in the spatial cognition literature.

Posters for UbiComp 2006 Accepted

Posted: July 18th, 2006 | No Comments »

My poster “Towards Design Strategies to Deal with Spatial Uncertainty in Location-Aware Systems” (Girardin, F., Nova, N., Blat, J.) has been accepted for UbiComp 2006 in Orange County, CA. Not surprisingly, the reviewer expect more preliminary insight or analysis. One feedback mentioned that I should relate my categories of reactions to spatial uncertainty according to the context and not the system.

In addition, Nicolas’ poster “Investigating How Automatic Disclosure of Partners’ Location Influences Mobile Coordination” (Nova, N., Girardin, F., Dillenbourg, P.) has also been accepted.

Relation to my thesis: An important milestone validating my first 10 months. One reviewer commented that he/she would like to see a submission of a full paper on the lessons learned and insight gained from the field study. I have the feeling this has mainly already been done by Benford et al. in Bridging the Physical and Digital in Pervasive Gaming and Can you See Me Now?. I might be writing such a paper with Mike Blackstock and Nicolas Nova on the lessons learned from the design and deployment of a pervasive game. The idea would be to coin the issues/challenges (constraints of location technologies, location awareness, spatial uncertainty) in performing a field study in form of a pervasive game as well as describing the impacts on the users and administrators.

Time now to learn how to analyze the CatchBob! data and think of a second experiment.

Prototypes in the Wild: Lessons from Three Ubicomp Systems

Posted: July 17th, 2006 | No Comments »

Carter, S. and Mankoff, J. 2005. Prototypes in the Wild: Lessons from Three Ubicomp Systems. IEEE Pervasive Computing 4, 4 (Oct. 2005), 51-57

Ubicomp research tends now to explore evaluation techniques including field studies that drive invention, early stage requirements gathering, and prototyping iteration. The authors evaluated three ubicomp systems at multiple design stages to provide a better understanding of how ubicomp evaluation technique should evolve. The designer must understand how to meet the user needs (what is evaluated) with the limits of feasibility depending on the availability of network connectivity and data, of sensors and algorithm for interpreting the data they produce, and of tolls with with to ease the building of applications.

The author’s suggested implication for evaluating interactive prototypes is:

Based on our experiences, we feel that field-based interactive prototypes provide invaluable feedback on a system’s use and co-evolution. However, they’re difficult and time consuming to deploy, and maintaining them unobtrusively is challenging. Designing for remote updates and using local champions and participatory design might mitigate these issues.

Relation to my thesis: I am considering evaluating my design (e.g. intelligible system to cope with spatial uncertainty) and in a field study to determine how well it performs. Based on my experience with CatchBob! I am concidering writing an article on the “Lessons learned from the design and deployment of a pervasive game”.

On the 802.11 Turbulence of Nintendo DS and Sony PSP Hand-held Network Games

Posted: July 17th, 2006 | No Comments »

Mark Claypool, On the 802.11 turbulence of nintendo DS and sony PSP hand-held network games. In Proceedings of the 4th ACM Network and System Support for Games (NetGames) 2005.

With the growth hand-held game consoles that support multi-player gaming over IEEE 802.11 networks, it has become important to understand the traffic chearacteristics of network games in order to build traffic models and adequately planning wireless network infrastructures to meet future demand. This study provides early answers to the following questions:

  • What is the network turbulence for hand-held network games?: Answer: Hand-held network games make frequent sends of small frames of data, typical of network games on other platforms.
  • Does the network turbulence for different hand-helds (such as the PSP and the DS) differ from each other?: The characteristics of Nintendo DS game traffic is different than that of the Sony PSP game traffic.
  • Does the network turbulence for different games (such as Ridge Racer and Super Mario on the same handheld differ from each other?: Games on the Nintendo DS have network characteristics fairly similar to each other, while games on the Sony PSP vary considerably from game to game.
  • Does the network turbulence for hand-held games differ from PC games?: The hand-helds send game data in sizes comparable to that of PC or console games, but hand-helds send data more frequently.

Does hand-held game traffic interfere with traditional Internet traffic on the same wireless channel?: In some cases, hand-held games can have adverse affects on the throughput for applications sharing the same WLAN channel.

Relation to my thesis: A very engineering-based study of wireless networks turbulence to build traffic models. It has some similarities with User-perceived Quality of Service in Wireless Data Networks. In distributed location-aware applications, Wireless network quality has a direct impact on location timeliness. This study suggests that wireless applications have different network characteristics. I could imagine changing the application traffic models to change according to the environment and the user’s activity in order to understand how people cope with turbulences impacting location timeliness.

Models of People, Places and Devices for Location-Aware Services

Posted: July 17th, 2006 | No Comments »

Assad, M. J Kay and B Kummerfeld 2006 Models of people, places and devices for location-aware services. In
proceedings of 4th International Pervasive Conference, Late Breaking Results.

The authors provide an overview of their Active Model (AM) to manage all elements of a ubiquitous environment: sensors, services, devices, rooms, and people. This contrast with work on other systems (work by Armind Dey or Jeffrey Hightower) that focus on managing data from sensors.

Their system uses an accretion/resolution representation. It provides a hierarchy of contexts, each acting as a namespace for the component modeled. AM uses subscriptons attached to components to drive information flow between models and other programs in context-aware applications. It has a service discovery that enables models of sensors, devices, people and places to be stored at arbitrary machines.

Active Model Figure1

Active Model Figure3

Relation to my thesis: a simple model for context-aware systems. I could use this model as a base to integrate the technical/physical constraints (the fuzziness of sensed space) and the layer of uncertainty inherent to “real-world” context-aware environments. Figure 2 shows a location information triggered with a user passing by proximity of a BT sensor. This can raise multiple misleading behaviors and informations (e.g. I am not at location g46, but I passed by in the hallway). The ad-hoc exchange of remote location without Internet connectivity raises the question of location timeliness.