MGuider: Mobile Guiding and Tracking System in Public TransitSystem for Individuals with Cognitive Impairments

Wei­Hsun Chen Department of Electronic Engineering Chung Yuan Christian University, Taiwang9776055@gmail.com

ABSTRACTIn collaboration with NGOs dedicated to supported employment programs, we propose the use of MGuider in public transit systems: a novelmobile guiding and tracking service, to increase work and life independence for cognitive­impaired patients such as people with traumaticbrain injury, cerebral palsy, mental retardation, schizophrenia, dementia, and Alzheimer’s disease.

Categories and Subject DescriptorsH.5.2 [Information Interfaces and Presentation]: User Interfaces–Evaluation/methodology, User­centered design, Prototyping, Screendesign; K.4.2 [Computers and Society]: Social Issues–Assistive technologies for persons with disabilities

General TermsDesign, Experimentation, Human Factors

KeywordsSocial Services, Ubiquitous Computing, Mobile Social Network Services, Cognitively Impaired.

1. INTRODUCTION

This study describes a location­based guiding and tracking service in public transit especially for individuals with cognitive impairments. Ina previous study[1], a mobile social network service prototype system was developed to help people with severe mental illness. We havefound that this system does not work well with subjects who travel more than an hour and change transportation modes two or three timesbefore they arrive at the workplace. Not only their parents/guardians but also their job coaches worry about the travelers’ ability to make suchtrips. The system that we proposed is expected to reduce anxiety and frustration by making essential information available ubiquitously.

For the purpose of guiding and tracking individuals, a lot of commercial navigation devices which are based on a GPS signal have beendeveloped. We have ourselves proposed an outdoor GPS­based and web­based tracking service for people with mental illness[1, 2].Unfortunately, we have found that these systems do not work for the many travelers who take the underground MRT because, in that case, theGPS fails. Our proposed system makes use of the Wi­Fi network. Taipei is the first city in the world with area­wide Wi­Fi usage. By July2006, 90% of the city’s population had access to the Wi­Fi network, which comprises more than 4,200 access points (AP). In addition,hundreds of APs have been set up for proprietary use. The abundance of information available through APs is adopted to build this guiding andtracking service. In other words, our approach adopts the existing information from APs and does not carry a huge cost to setup infrastructuresfor indoor positioning. The Taipei Mass Rapid Transit (MRT) where more than 1000 APs have been set up in 68 stations was first chosen asthe test environment.

2. SYSTEM ARCHITECTURE AND IMPLEMENTATIONThe proposed system architecture is shown in Fig. 1. A general purpose PDA cell phone is adopted as the client device, and we implementthe required functions as a cell phone application. It has two advantages: first, the general purpose device is much cheaper than a specificdevice. Secondly, a user can choose any kind of cell phone he/she likes and use this service as a modern cell phone application such as MP3and flash games. Also, there will not be any labeling effect when people with mental illness use those devices. From interviews of caregiversand people with mental illness, we have found that subjects hate all devices that reveal their handicap to others. This dislike is an importantreason that some assistive programs fail.

Fig. 1. System architecture

A use case is illustrated in Fig. 2. When the user chooses a station to get off, the handheld device will pop­up a photo to indicate the rightdirection. When the train leaves the station before the one where the user is to get off, marked as (2) in Fig. 2, a message window will showon the device. Moreover the handheld device will vibrate and/or sound for 3 seconds in a special fashion to alert the user. If the user missesthe station or takes the wrong direction, is marked (3) in Fig. 2, the handheld device will alert the user by vibration and/or sound until the userpresses the “OK” button. We also implement the location inquiry service and location monitor service which set up a region and timebeforehand. At a specified time, a short message alert will be sent to the caregiver to report whether the user did or did not arrive on schedule.This function is helpful especially when the caregiver is nomadic.

Figure 3 shows the web page of the monitor service, Fig. 3 (a) shows a historical track of user movement. Fig. 3(b) shows the alarm eventsetup page. Caregiver can define the events, including time and location, for a user beforehand. The event is generally the time of the person

with mental illness takes MRT for work or the time of he/she arrives at workplace. If a user triggers one of the events, a short message alertwill send to the caregiver. This function is helpful especially when the

Fig. 3(a) Web­based tracking service: historical track

Fig.3(b) Web­based tracking service: alarm event setup (time and location)

3. EXPERIMENTAL RESULTS AND FEEDBACKJob coaches from five Taipei­based rehabilitational hospitals helped us to find six people to be our experimental subjects in a fieldexperiment. Four different situations were designed for this experiment. The situations A to D are tabulated in table l. To make sure that

subjects were not just memorizing a route, the three routes each start from a different station and end at a different station. The experimentprocess is shown in Fig. 4.

Fig. 4. Field experiment flow Table 1 Experimental Situations

A • without PDA • Tell the subjectorally which station to get off.

• To check whether the subject can take thetrain in the correct direction without the helpof the PDA.

B • without PDA • Tell the subjectorally which direction to go andwhich station to get off.

• To check whether the subject can get offcorrectly without the help of the PDA.

C • Demo the system by experimentassistant.

• To teach the subject the operation of thePDA.

D • with PDA • Tell the subject orallywhich station to get off.

• To observe whether or not the system canhelp subject.

After the experiment, feedback was collected from the subjects. We scored each term from one to five points and asked the subject howhe/she felt before and after the experiments. The higher rating, the more that the subjects agreed with a term. Table 2 provides informationabout the subjects and reports the results of each experimental situation and the users’ responses to the questionnaire survey. We find mostsubjects agree that the system is “easy to operate”, “helpful on travel”, and “practical”. Before the experiment, two subjects said that they donot like to use the PDA. We found that they are not cell phone users. However, their degree of opposition went down after using the guidingsystem. We also learned that a vibration prompt is more useful than a sound prompt to people with mental illness. A system demo video canbe found on YouTube (http://www.youtube.com/watch?v=11DfVWf7cew).

Table 2 Experimental Results

Subject 01 02 03 04 05 06

Age 23 37 27 44 41 21

Gender M M M F F F

Relation (H:head injuryC:chronic mental illness)

H H H C C C

Phone user Y N Y N N Y

Experiment A (Success,Failure) S F S S F S

Experiment B (Success,Failure) X F X X S X

Experiment D (Success,Failure) S S S S S S

Easy to operate 4 3 5 4 3 5

Vibration prompt 5 3 5 4 5 4

Sound prompt 2 2 2 2 1 2

Helpful on travel 4 4 4 4 5 4

Practical 5 3 4 4 4 4

Unwilling to use beforeexperiment 1 4 1 4 2 1

4. REFERENCES[1] Yao Jen Chang, Hung­Huan Liu, and Tsen­Yung Wang, “Mobile Social Networks as Quality of Life Technology for People with Severe Mental

Illness,” IEEE Wireless Commun. Mag. June/July, 2009[2] Yao­Jen Chang, Hung­Huan Liu, Shu­Min Peng, Tsen­Yung Wang, “Potential of mobile social networks as assistive technology: a case study in

supported employment for people with severe mental illness,” in Proc. ACM ASSETS 08, Halifax, Nova Scotia, Canada, Oct. 13­15, 2008, pp. 239­240.