Final Report of ITS Center Project: Regional pedestrian activity measurement

A Research Project Report

For the ITS Implementation Research

A US DOT University Transportation Center

REGIONAL PEDESTRIAN ACTIVITY MEASUREMENT (PROJECT 434911)

Principal Investigator:
Aaron Schroeder, Ph.D.

Virginia Tech Transportation Institute

3500 Transportation Research Plaza (0536)

Blacksburg, VA 24061

Phone: 540-231-1505

Fax: 540-231-1555

September 2006

Disclaimer

The contents of this report reflect the views of the authors, who are responsible for the facts and the accuracy of the information presented herein. This document is disseminated under the sponsorship of the Department of Transportation, University Transportation Centers Program, in the interest of information exchange. The U.S. Government assumes no liability for the contents or use thereof.

Table of Contents

Words of appreciation	3
Project overview	4
Project objectives	4
Project tasks	4
Project accomplishments and findings	5
Conclusions and recommendations	18

Appendices

Appendix A – Communications	24
Appendix B – Technologies (product web sites)	25
Appendix C – Literature review paper	26

List of Tables and Figures

Figure 1 – The Nextel Motorola i605	11
Figure 2 – The Nextel RIM 7100i	12
Figure 3 – The HP iPAQ iPAQ hx2495	13
Figure 4 – GT1M Actigraph	14
Figure 5 – The Globalsat BT338	15
Figure 6 – The SYSONCHIP SMART BLUE MINI	15
Figure 7 – The Holux GPSlim236	15
Figure 8 – The Trackstick	16
Table 1 – A comparison of initial wearable concepts as compared to evaluated concepts	19

Words of Appreciation

This effort greatly appreciates the resources and time the following individuals and organizations provided.

The U.S. Department of Transportation, University Transportation Centers Program, and the Virginia Tech Transportation Institute – for their fiscal and resource support.

Nextel, specifically Helen Franks and Marselle Culpepper for their willingness to loan us two phones, associated service, and applications.

Kathy Hosig, Ph.D. and Lisa Schweitzer, Ph.D. for their invaluable expertise.

Project overview

American society has become automobile-centric to such an extent that any inquiry into alternative modes of transportation – those modes that are not dominant – frequently finds little response as little data or information exists for such modes. The ever-increasing general awareness of the systemic nature of resources that began in the 1990s spawned an extensive set of inquiries that attempted to reach into the environmental and health benefits of alternative modes of transport. Lacking data on alternative modes, practical inquirers set out to determine if existing automobile data collection mechanisms could be used for alternative mode data collection. For example, transportation professionals sought additional utilization of existing traffic cameras, capable of counting and classifying automobiles, to also count pedestrians. Though this approach seems practical, the assumption that pedestrians follow the same rules and roads as the automobile is questionable.

To better understand pedestrian behavior, oral and written surveys and travel diaries have often been used. But these can lack accurate spatial characteristics of movement, as the participant may not convey all information. Technical data collection has improved this. Wearable technologies that collect the pedestrian’s spatial location and prompt them to provide a response as to why they have just changed direction, etc. have been used. While collecting a tremendous amount of information on a pedestrian’s location, and their decision-making, they can impede the pedestrian’s progress, as they will interrupt the pedestrian’s routine with inquiry. However, a large-scale deployment of such wearable tracking technologies – to collect the whereabouts of a population of participants – combined with land use and other data sets to provide a comparative commentary on participants’ movement – may reduce the challenges of a survey of individuals while providing a significant amount of information to inquirers as to human movement in a region. Further, given the nature of funding for organizations interested, and given the technological capabilities of today’s wearable devices, it may be of great interest to team between several disciplines, provide one wearable technology architecture, and glean data relevant to multiple disciplines’ inquiries.

It was the impetus of this effort to provide a review of those who would be interested in such a study, and take a quick look at wearable technologies and their associated wearable architecture arrangements in order to establish the basis for deploying something of this nature. This effort revealed that those disciplines interested in human movement through a region are quite diverse, ranging from public safety to biomotion. However, teaming for an immediate co-beneficial technology deployment would be those involved in the health and well-being of a person (for example, physical activity) and those involved in transportation (for example, transportation planning and engineering).

In terms of wearable technologies this effort developed and evaluated six wearable architectures and found that at least two, with some modification, would be worth further exploration. The critical features in their use between the researchers and the participant (the wearer) are cost, the number of devices to carry, and the number of steps involved in device maintenance. Minimizing all is critical to the success of a future deployment.

This project’s initial objectives and tasks follow.

Project objectives

The goal of this project was to develop a detailed understanding of what would be required to undertake a wearable-technology pedestrian survey and to establish, as a foundation, the next step of technology prototyping. Over the long term, the goal would be to develop and deploy a wearable-technology pedestrian survey using wireless technologies, Global Positioning System (GPS) receivers, and clothing-integrated accelerometers. Such a deployment would benefit researchers in multiple domains including: human health and medicine, civic planning, and transportation.

Project tasks

The tasks as initially drawn out for this effort include those listed below. Many of the tasks were conducted simultaneously.

· Review literature on pedestrian movement: Macro (region-wide) - automated tracking, surveys, or systems similar to the one described above; Micro (human physiology) relative to transportation systems and facility design - how may accelerometer systems help to improve design under 'real-world' survey?

· Review technologies: Macro (reviewing portable GPS technologies); Micro (reviewing human-movement assessment technologies such as wearable accelerometers).

· Assess the feasibility of integrating technologies while considering the pedestrian survey participant: technology integration (wireless connectivity vs. data storage); human-technology integration; and cost.

· Identify key stakeholders who are interested in this area of research and begin to establish collaborative relationships.

· Conduct real or virtual 'round-table' sessions with domain experts to determine overall feasibility and validity - "if such a survey were possible, in what might you be interested?"

· Develop prototype technology concept and survey deployment schemes.

· Develop final report synthesizing above findings.

Project accomplishments and findings

Review of the literature

The initial phase of this effort began with an examination of the international and national interest in the study of human motion. This snapshot provided insight into cross-discipline interest and nomenclature. The review culminated in late October of 2005 with a presentation to Association of Collegiate Schools of Planning (ACSP) conference in Kansas City. The presentation of the paper, “Pedestrian Activity Measurement: A Review of the State of the Art and the State of the Practice,” was given in a new session at the conference, Built Environment and Physical Activity. The new track serves as a nexus of health and urban planning academics and practitioners. It quickly became standing room only – clearly demonstrating that the communities of health and urban planning are ready to commit to formally discussing, and addressing, the issues with land use and physical wellness. With urban planning’s close association to transportation engineering, it seems likely that a health, planning, and engineering dialogue will commence on the same topic.

The initial findings presented were the highlights of a review encompassing the many disciplines that have an interest in pedestrian activity measurement. Dominant were the urban planners and transportation engineers. These disciplines collect data on pedestrian movement through a region or at the streetscape (for example, a count of pedestrians crossing at an intersection). Disciplines interested in the physical wellness of the pedestrian also had representatives who were also very interested in the effort. Such wellness of the pedestrian includes: the physical security of the individual, for example, walking at night with or without street lighting in an area known to have a high crime rate; the safety of the individual walker, for example, the ability of the pedestrian to evacuate a building or a region; and the health of the walker proper (e.g., the motion of the body through space across varying terrain [biomotion studies]).

The full details of this research may be reviewed in Appendix C, where “Pedestrian Activity Measurement: A Review of the State of the Art and the State of the Practice” is presented.

Identification and communication with people and disciplines of interest

Review of the literature still left a series of practical questions unanswered: If a study were to be conducted locally and regionally, who might be interested in the movement of people? Who might be experts in conducting practical experiments involving people in general? Who might be in need of data or information on the movement of people in general? In answering these questions for this effort, an attempt was made to communicate with local, regional, and statewide actors that might have interest in seeing a project evolve to capture data on pedestrian and regional human movement in general. This search began in the organizations encompassing the Virginia Tech Transportation Institute (VTTI). This included a search of Virginia Tech, Blacksburg (the town in which Virginia Tech resides), and the state of Virginia. It is unusual for a region to have access to the technological sophistication that Virginia Tech offered. In this regard, our effort had a significant advantage over regions that do not maintain such a University. However, the other institutions, the inter- and intra-regional actors involved in health, planning, transportation, safety, pedestrian and bicycle activism, etc. are not necessarily unique to this region. As such, any follow-on research or deployment would be able to identify similar actors in their regions that may wish to partner, or assist, with the research or deployment of such tracking technologies.

Organizations that may prove of universal interest to such an activity include:

· Regional pedestrian, hiking groups, or bicycling

· Planning offices

· Safety offices

· Engineering offices

· Transportation offices

· Health and nutrition organizations

A complete list of communications may be reviewed in Appendix A.

Development of initial concepts

Prior research experience in wearable technologies, a review of associated literature, and communications with international, national, and local experts led to the development of several conceptual systems for capturing and analyzing data on pedestrian location. These systems included a field and desktop technological component. The desktop component was similar across all conceptual varieties. The desktop technology included a computer connected to the internet capable of connecting to the field devices either directly or through the internet: this desktop system was the central repository for collected data and could serve also as a data analysis and sharing mechanism.

The field technology component for any of the concepts was to be a collection of wearable technologies that afforded information about the wearer’s location and movement. These devices were to provide this information with minimal impact on the wearer. That is, one would affix them to their person, activate the technologies, and go about their daily routine. At no point should the wearer need to reactivate or respond, or otherwise interact with these devices till the end of their daily routine when they would likely need to perform some kind of daily maintenance ritual with these devices, such as downloading data or charging the batteries. The hope being that while worn, the individual wearer would forget that he or she was participating in a study, thereby reducing user bias.

In should be noted that there were two papers that proved critical in the development of these concepts. The papers provided documented examples of real-world data collection and rapid analysis techniques. Any further investigation into deployment of such technologies should involve a review of papers and their associated research.

Oliveira, et al., used two data-logging field technologies, an Actigraph accelerometer and a Geostats Wearable Geologger GPS receiver, to capture the location and movement of an individual.[1] Following data capture, a proprietary data analysis system, GeoStats Trip Identification and Analysis System (TIAS) was used to determine the individual’s activity and assign a probability of transportation mode of the wearer’s daily activity. The technological application of this research proved uniquely compelling to the development of the wearable concepts for this effort. In their research, an individual wearing such technologies was capturing travel origin and destination information, and the technologies that were assigned to collect movement information, number of steps taken or level of activity, was also being used to associate with the location information to provide modal information. In one instance, multiple disciplines’ inquiries into the condition of a pedestrian were capable of being addressed.

Doherty et al. used a Bluetooth-enabled cell phone in combination with a Bluetooth-enabled GPS receiver to collect information on an individual’s location in near-real-time.[2] A GPS signal collected by the GPS device was sent to the cell phone via Bluetooth, and the cell phone, with appropriate service, then sent that information on and through the internet to the researcher’s central repository for analysis. Additionally, their design used the unique capabilities of the cell phone to allow the wearer to respond to a location-based prompted recall survey. It was their intention to find out more about travel habits through such prompted recall. While their technological sophistication was one that this effort sought to emulate, the two efforts differed philosophically on the prompted recall. In theirs, they actively captured additional information from the wearer when that individual approached a specific location. In our effort’s concept, it was believed that such prompted recall might interfere with an individual’s decision-making processes on choice of path or mode, thus, the movement alone, in combination of other data sources, would provide data for later analysis.

Further communications with Doherty revealed additional capabilities that had been developed.[3] His team had established a sever which would accept Geospatial Information System (GIS) files of a region’s roadway network and land use as well as any GPS tracks collected by an individual wearing technology as described above. This information would then automatically generate a probability of the individual’s transport mode. Thus, the simple technology that provides a location for the individual, when compared with additional information, can provide insight into that individual’s movement to address multiple disciplines’ inquiries.

The analytical capabilities the aforementioned research efforts were well documented and sound. They demonstrated that there were stable and accessible applications for data analysis that could accept inputs from a wide variety of standardized technologies to provide insight into pedestrian movement. This suggested that our initial objectives could be more focused; our effort could focus on how to capture and store the data rather than how to analyze the data. Thus, our efforts focused in on determining how friendly wearable devices were in terms of cost, comfort, configuration, and data collection.

The VTTI research effort’s initial conceptual architectures included:

· Wearable Concept 1 – disparate data loggers. In this architecture there is a wearable accelerometer that is capable of storing some quantity of activity data (at least a day’s worth at 1-second intervals). There is also a wearable GPS device capable of storing some quantity of activity data. In such a case, some maintenance of the devices is required. Data would need to be downloaded and the device’s power supply replenished. This concept is similar to that defined by Oliveira, et al.[4]

· Wearable Concept 2 – a data storage device wired to two collectors. In this instance, an accelerometer is attached to a wearable storage device that is simultaneously connected to a GPS unit. Thus, the participant carries three devices, wired together. The computational device could include a laptop or a handheld computer, which collected and stored the data for later download. Maintenance for this would require downloading data but from one device, and replenishing the power, but this time, for three devices.

· Wearable Concept 3 – data storage device wirelessly connected to two collectors. This concept is identical to Concept 2 but the storage device is connected via wireless short-range communications, such as Bluetooth, to the peripheral accelerometer and GPS device. Again, like Concept 2, this device would have a download requirement from one device and a power-replenishing requirement for three devices.

· Wearable Concept 4 – data conveyor wirelessly connected to two collectors. This concept is similar to Concept 3 in that there are no wires connecting to any of the local (wearable) devices, but the storage device is swapped out for a device which first collects the local data and then conveys the data elsewhere, presumably, to a server maintained by the researchers. In this concept, the GPS and accelerometer peripherals are wirelessly connected to a cell phone that transmits its information through the internet to a server for storage. Here too, three devices would require power replenishment. However, data download is conducted automatically. Minus the accelerometer, this concept is similar to that defined by Doherty, et al.[5]

· Wearable Concept 5 – data conveyor wirelessly connected to two collectors. This concept is identical to Concept 4 but a WiFi-enabled handheld computer replaces the cell phone. Data is collected from the peripheral devices and logged until the central device locates a ‘friendly’ WiFi service, automatically connects, and sends its information to a server. Like Concept 4, power replenishment is the only frequent maintenance requirement, unless a friendly network cannot be located in some amount of time.

· Wearable Concept 6 – integrated conveyor and one collector. Here, the peripheral GPS device is replaced by a cell phone (conveyor) with integrated GPS chip and wirelessly connected to an accelerometer. In this instance, there is no data maintenance required; there is only power replenishment for two devices.

· Desktop Concept – data collection and sharing for analysis – The original concept for the database design was to create an integrated system that is easy to upload information into and display the results. The components to this system included: a high-speed internet connection; a dedicated IP address; a web server; a database; an automated mechanism to upload data from field devices to the database; an automated mechanism to graphically display location information; and a connection to the internet to share collected data.

Refining concepts and evaluating technologies

Reinterpreting concepts into reality, even such as those so well documented in the papers described above, are often challenged by reality. Our effort contended with the following requirements: test several technological aspects of several concepts (size, weight, ability to provide useful data); a 5000-dollar technology budget; human resource restrictions that would allow our study to mimic that which would be available to a likely future champion of such a study: local governments and city planners. The considerations for technology selection in our effort follow.

Wearable Concept 1 called for a wearable data-logging accelerometer and GPS device. The GPS device used by Oliveira, et al., was no longer available at the time of this effort.[6] Further, the GPS device they had used required the use of a backpack. Though much less substantial than those used 5 years prior to the writing of their paper, their GPS device had a small antenna placed on the shoulder pad of the backpack of the participant and the primary electronics in a small pouch that would reside within the backpack. Compared to the scale of the accelerometer they were using, this seemed quite large. The GPS device they had used conflicted with our effort’s focus on assuring minimal technological interference with the individual wearer’s daily routine. Thus, a low-cost, lightweight, and compact GPS data logger was sought out. Though GPS accuracy, data-storage capacity, and battery life likely would suffer as compared with the GeoStats device, our effort chose the Trackstick for its simple design and small size to serve as GPS data logger in Wearable Concept 1.

As for the data-logging accelerometer identified in Wearable Concept 1, the GT1M ActiGraph accelerometer used by Oliveira, et al., was still available and affordable and so was acquired for our effort.[7]

Wearable Concept 2 called for a mouse-like accelerometer and mouse-like GPS to be simultaneously attached to another device that could be used to store the collected data. This design quickly proved infeasible. First, two devices connected to another with wires would become quite a hindrance to any wearer of the technology. Second, most mobile systems capable of hosting two wired Universal Serial Bus (USB) connections (the preferred wired connector for small, mouse-like, devices) are laptops, so the weight and the cost would quickly skyrocket. Wearable Concept 2 was no longer considered.

Wearable Concept 3 called for two small, nearly unobtrusive devices, connected wirelessly to a third small device that collects data and stores it for later download. Concept 3’s basic wearable wireless trio design is consistent through Concepts 4 and 5 where two data providers are sending data to a third data handler. As such, technological acquisition could focus on a few technologies that could double or triple time across the evaluation of each concept. Wearable Concepts 3, 4, and 5 all seek a Bluetooth (local wireless) enabled GPS device. This device would need to be fairly small, durable, reliable, accurate, and easy to maintain (simple and infrequent charging). After exhaustive research as to the accuracy of the newest available retail GPS chips, three GPS devices were selected.[8] Three different providers were selected because as while the chips remained the same, the batteries, charging technique, provided software, and the housing all varied somewhat. These were the Globalsat BT338; Sysonchip Smart Blue Mini; and Holux GPSlim236.

Wearable Concepts 3, 4, 5, and 6 all seek a Bluetooth-enabled accelerometer. At the time of the technology selection and acquisition phase of this effort, there were very few options for this component. Through conversation with Mr. Doherty,[9] a Bluetooth-enabled accelerometer was identified as being in production and sale through the Australian firm, Alivetec.[10] Indeed, this firm’s product offering included a Bluetooth-enabled accelerometer coupled with a heart monitor that communicated its information to a Bluetooth-enabled cell phone and on to a centralized monitoring service. This concept is very much akin to those presented here. However, being coupled, the device had a cost of around $1000, which was prohibitive in this effort.[11] At the time, the only other alternative was to assemble a device based on the schematics outlined by a Georgia Tech engineer.[12] While plausibly inexpensive in terms of materials, is also seemed plausible that it could become quite expensive in the time involved to identify a VTTI engineer capable of assembling the device, the time to build the device, the time to calibrate and test the device in a way that is behaved in a fashion similar to the device used by Oliveira, et al, etc.[13] Thus, it was decided that the Bluetooth accelerometer in the wearable concepts would be temporarily set aside and our effort would use the ActiGraph device to serve as a fill-in as its data captured and size would likely mimic a real Bluetooth accelerometer. Not surprisingly, by the time of the writing of this report, there are more Bluetooth accelerometers available on the retail markets. However, they are generally tied in to complete, individual, health-monitoring packages, and as such, remain relatively pricey, and their analytical software has been developed for a very specific use.

Wearable Concepts 3 and 5 both call for their third device to be capable of storing the data for later transmission. Where Concept 3 assumes that the data transmission will be through a physical connection, Concept 5 augments that with a capability of transmitting the data via a ‘friendly’ WiFi connection. That is, when the storing device enters the range of a previously identified wireless network, and it determines that there is an internet connection through that friendly network, it then sends the collected data. There are a lot of similarities between the two devices. Concepts 3 and 5 both must have a Bluetooth capability and must be able to store data. At the time of the selection process for this effort, there were several capable technologies that were small enough and relatively inexpensive enough to perform these basic functions, not to mention capable of being programmed and connecting to a WiFi service. Since a device with WiFi can also store data, two devices were required to serve as a test device for two concepts. Handheld PCs and Palm devices were considered and of the wide variety of those available at the time, the Hewlett-Packard iPAQ hx2495 Pocket PC was selected.

Wearable Concept 4 differs from 3 and 5 in that the central collection device is designed to immediately convey the data, through cellular service, through the internet, to a centralized database. Where the selection of the Bluetooth accelerometer was daunting in its lack of availability, the selection of a cellular phone and service were daunting as our effort had to consider a multitude factors: 1) identify the services available in Blacksburg, Virginia and that would allow for functionality throughout the remainder of the Commonwealth of Virginia; 2) identify a cellular-service provider that worked efficiently with the State’s purchasing system (timely acquisition was a consideration); 3) identifying a cell phone that would work with the service and our devices. This last consideration was particularly complex. The phone would have to have a Bluetooth capability; it would have to have to be programmable (preferably Java); and, since Wearable Concept 6 seeks a cell phone with GPS to replace the external GPS device, the phone would also have to have a GPS device that was integrated and accessible (to programming). While the e911 mandate has influenced cell-phone manufacturers to produce cell phones with integrated GPS capability, there are few services that actually allow the owner of the phone to access the GPS chip. As it turned out, the company at the top of our list for service and phones provided us with two technology demonstrators: Nextel provided the Nextel Motorola i605 and the Nextel RIM Blackberry 7100i as well as the necessary services to facilitate our effort. In addition, Nextel has a rich line of enterprise applications designed for businesses to track their employees’ cell phones and let employees share their location with fellow employees. As such, our effort had the opportunity to use their services within our research context.

One further note on technology availability: at the time of the writing of this report, Bluetooth-enabled devices with WiFi capability, cellular capability, and storage capabilities were just starting to become available. These would have been ideal to test; and when they become available with GPS, they may too serve the purpose of supporting Wearable Concept 6.

The Desktop concept will be addressed further below. In essence, however, it included a Dell Latitude running Microsoft XP and including Office XP. It was connected to the internet through a high-speed connection with a dedicated IP address. Any additional software installed on the machine was derived from the specific technologies our effort acquired, such as data extraction software for the accelerometer. Any additional software development, from the database to the web services to the automated uploading to the programming of the disparate wearable devices, utilized open source applications and forums. The choice for this was simple: as inexpensive yet workable as possible.

The individual technologies evaluated were either field (wearable) or desktop (analytical) in classification. Details on those acquired, configured, programmed, and evaluated in this effort follow.

Field technologies

Nextel Motorola i605[14]

Product description – Nextel Motorola i605 is a multifunction and rugged (US Milspec 810F) cell phone. The device used in this effort had an integrated GPS location capability, was Bluetooth enabled, was Java programmable, and could access the internet via the Nextel GSM cellular network. The device is depicted at right in Figure 1.

Intended use – Wearable Concepts 4 and 6 called for such a device. In Concept 4, the device would collect data via Bluetooth from both an accelerometer and a GPS device and then retransmit it to a central server for storage and analysis. In Concept 6, the device would perform the same function but would transmit its own GPS signal in lieu of an external Bluetooth-enabled GPS device.

Actual use – Due to the inability to program this device as data transfer conduits, only a hybrid of Wearable Concept 6, and not Wearable Concept 4, was able to be supported by this device.

Cost(s) – $129.99 (i605) + $32.79/mo. (Nextel Free Incoming 300) + $ 21.99/mo. (TeleNav Track Premium) + $3.00/mo. (Public I.P.) + $10.00/mo. (Data Access) = $197.77 (for the first month) and $67.78 (for each month following)[15]

General comments – The strengths for this device are its ability to acquire, hold, and retransmit a GPS signal as well as its overall ruggedness. While the i605 is not as good as the stand-alone Bluetooth-enabled GPS devices examined in this effort, in particular in terms of spatial accuracy, signal acquisition and hold, it still performed reasonably well. The performance was good enough that one could still develop a very good picture of human movement through a regional space. The immediate drawbacks are its aesthetics, size, and weight. Its bulk could interfere with the daily routine of an individual, especially if there were other peripheral technologies involved along with using this as a central communications device. In addition, battery life was less than anticipated. However, its battery performed substantially better than the TrackStick and the Blackberry 7100i – lasting at least a day before requiring recharge.

Nextel RIM Blackberry 7100i[16]

Product description – The Nextel RIM Blackberry 7100i is a multifunction device that serves as a personal digital assistant (PDA) and a cell phone. The device used in this effort had an integrated GPS location capability, was Bluetooth enabled, Java programmable, and could access the internet via the Nextel GSM cellular network. The device is depicted at right in Figure 2.

Intended use – Wearable Concepts 4 and 6 called for such a device. In Concept 4, the device would collect data via Bluetooth from both an accelerometer and a GPS device and then retransmit it to a central server for storage and analysis. In Concept 6, the device would perform the same function but would transmit its own GPS signal in lieu of an external Bluetooth-enabled GPS device.

Actual use – Due to the inability to program this device as data transfer conduits, only a hybrid of Wearable Concept 6, and not Wearable Concept 4, was able to be supported by this device.

Cost(s) – Cost(s) – $199.99 (i7100i) + $65.59/mo. (BlackBerry National Team Share 400) + $ 21.99/mo. (TeleNav Track Premium) + $3.00/mo. (Public I.P.) + $10.00/mo. (Data Access) = $300.57 (for the first month) and $100.58 (for each month following)[17]

General comments – The Blackberry 7100i is an attractive device with many capabilities that were not intentionally evaluated by our effort. Such attributes of aesthetics and personal functionality might prove useful in a future design where the central device being used to collect information is also intended to be a benefit to the participant. The device, while technologically fascinating, fell short of expectations on battery life (including the i605 and the iPAQ, this device had the shortest battery life when transmitting GPS data) and on apparent durability (it felt as if it needed to be cared for – seemingly low-grade plastics). However, when it was shielded in its holster and affixed to a belt clip, its relative flatness allowed the wearer to go about activities without noticing. Of course, if the wearer were wearing clothes without the need of a belt, placement might become more challenging – though, its performance (GPS acquisition and transmission) suggested that carrying it in a purse or a backpack would not be unreasonable. The caveat was that this device seemed to have a tougher time acquiring and holding a GPS signal than the i605.

Hewlett-Packard iPAQ hx2495 Pocket PC[18]

Product description – This device is classified as a handheld, or pocket, PC. While diminished in performance, it has the capability to perform most tasks that a laptop or desktop PC using conventional operating systems. Ours was configured with an additional 2 GigaByte (GB) Secure Digital (SD) memory card for additional storage. The device had an additional Compact Flash (CF) slot for additional hardware peripherals. This iPAQ also had Bluetooth and WiFi communications (802.11b) capabilities. The device is depicted at right in Figure 3.

Intended use – Wearable Concepts 3 and 5 called for a third device to store and send collected data respectively.

Actual use – Due to a communications problem with this device and the local ‘friendly’ network (a Virtual Private Network (VPN) connection was unable to be established and therefore automation of the data collection and dissemination process was not feasible), Wearable Concept 5 could not be evaluated. Therefore, this device served as the storage device for Wearable Concept 3 only.

Cost(s) – $419.99 (iPAQ) + $69.65 (2GB SD card) = $489.64

General comments – The GPS/PDA combination worked well with a messenger-style bag with the GPS unit attached to the shoulder strap and the PDA inside the bag. The PDA is a bit large/heavy/awkward when carried in a pants pocket. There have also been a few instances where the power button on the PDA was unintentionally pressed in the both the bag and pocket, this problem was corrected by moving the PDA into its own section within the bag and removing anything else from the pants pocket.

The device did require a great deal of configuration just to achieve Wearable Concept 3’s design requirements. First, the device needed to be configured to communicate with a Bluetooth-enabled GPS; second, and more challenging, this device needed to be configured to store that information in a data logging fashion; third, the device would need to be connected to a host PC to download the data. The first and third steps were relatively easy to accomplish. However, the second task required a third-party application to be installed on this device. For this project the data logger developed by KRMicros was used to record the data.[19]

The iPAQ was not designed as a ruggedized device. As such, the user must treat it like the fragile computer it is; it is not water resistant and it does do well with temperature extremes. Addressing such flaws, as well as making it a smaller, would make this a very attractive candidate for field use.

GT1M ActiGraph[20]

Product description – This device is a wearable accelerometer and data logger. An accelerometer detects shifts in acceleration. In this instance, the device can be used to measure human motion in one dimension. Thus, when affixed to an individual’s waistline, (e.g., belt) the device can measure acceleration along that plane. In such a capacity it can capture information on an individual’s gait and serve as a kind of pedometer (measuring step frequency). The device is depicted at right in Figure 4.

Intended use – Wearable Concept 1 called for a data-logging accelerometer to serve as either a pedometer or a device to measure gait characteristics. The GT1M served that purpose.

Actual use – Due to the inability to acquire a Bluetooth-enabled accelerometer, the ActiGraph would serve Wearable Concepts 3 through 6 as a defacto Bluetooth-enabled accelerometer. If the USB connection on the GT1M were replaced with a Bluetooth connection, this seemed a quite plausible design possibility.

Cost(s) – $399 (device) + $3 (connector cable) + $300 (ActiLife software) = $702 (it should be noted that one could have more than one device associated with one license/instance of the software)

General comments – In terms of the hardware and its ability to collect data, our effort was very pleased with the GT1M. It was small, rugged, water resistant, and lightweight. It was so convenient to carry on a belt that our testers frequently forgot they were wearing the device. This has tremendous benefits when conducting such a survey as it removes impedance from daily activity. However, clothes that do not require a belt might prove problematic.

The device was also impressive when it came to its ability to remain ‘active’ – that is, when recording data at its most frequent setting, the device had memory capacity and battery capacity to continually operate beyond a 24-hour period. This was better than any other device our group tested. It was also fairly easy to connect the device to a USB port for data download and recharging.

The device did have its drawbacks, specifically the software that came with the device. Establishing the software connection between the host computer and the GT1M was often troublesome. Configuring the device once a connection had been established was also undependable; our group had a great deal of trouble with the time-to-start feature.

Bluetooth GPS Units: (a) Globalsat BT338[21], (b) SYSONCHIP SMART BLUE MINI[22], (c) Holux GPSlim236[23]

Product description – Each of these devices are:

· GPS receivers using the SIRF Start III chip;

· Capable of transmitting GPS information via Bluetooth technology;

· Stand-alone devices that contain an internal, rechargeable, battery.

Intended use – Wearable Concepts 3, 4, and 5 all called for the use of a Bluetooth-enabled and independent GPS device. Though markedly similar, and containing the same GPS chip (which had been selected as being the most accurate retail GPS chip), the external encasement, the battery and its life, were expected to vary somewhat. The Globalstat BT338 is depicted upper right in Figure 5. The SYSONCHIP SMART BLUE MINI is depicted middle right in Figure 6. The Holuz GPSlim236 is depicted lower right in Figure 7.

Actual use – Due to the inability in the allotted time of this effort to successfully program the phones to connect to the Bluetooth devices and retransmit their data to a central server, these devices were only used in the case of Wearable Concepts 3 and 5 where they were paired with the HP iPAQ.

Cost(s) – (a) $121, (b) $166, (c) $108

General comments – These were very impressive devices. They exceeded our expectations on their ability to acquire and hold a GPS signal where other devices have historically failed. When used on our field trips the device in a car, it could be left on the dash or in a cup holder, on the person, strapped on a belt (using rubber bands), strapped onto the shoulder of a backpack (using rubber bands), left in an outer pouch in a backpack, or placed in a pocket. All this worked as long as the individual was outside and in fair weather. If inside, and in an outer room with large windows, the device seemed capable of acquiring GPS signals.

Packaging was adequate for placement on car dashboards, or in exterior backpack pockets in fair weather. However, it was not adequate for direct exposure to water.

As to device maintenance, plugging the devices in for power recharging was simple enough. Collecting data from them to the data collection device was easy as well, and so long as the data collection device had a contemporary operating system and had Bluetooth, establishing a connection was fairly easy.

TrackStick GPS Data Logger[24]

Product description – The TrackStick GPS Data Logger is a device that logs a GPS signal at some predetermined rate. The device is depicted at right in Figure 8.

Intended use – This device was intended for use in Wearable Concept 1 as a wearable companion to a data-logging accelerometer.

Actual use – The TrackStick was used as intended in Wearable Concept 1.

Cost(s) – $258

General comments – The TrackStick, out of the box, held appeal because of its