Distributed and synchronized users’ profile management for Ambient Assisted Living

A. Esteban#1, V. Jimenez-Mixco#2, M.F. Cabrera-Umpiérrez#3, M.T. Arredondo#4

# Life-Supporting Technologies, UPM C/Ciudad Universitaria s/n

ETSI Telecomunicación 28040 Madrid-SPAIN

1aesteban@lst.tfo.upm.es 2vjimenez@lst.tfo.upm.es 3chiqui@lst.tfo.upm.es

4mta@lst.tfo.upm.es

Abstract—This paper presents the Oasis Health Monitoring System (OHMS), developed within the EU FP7 funded project OASIS, as a new approach for the next generation of monitoring systems. OHMS allows physicians to perform continuous monitoring of the elderly patient, through a distributed system of synchronized XML profiles. This solution ensures that the accessed information is updated and validated in both sides of the communication, the elderly and physician clients, through the use of Web Service technology and OSGi architecture. The OHMS will be tested within OASIS pilots in several European countries, where the system functionalities will be assessed in a semi-controlled environment. The outcomes of these tests will help to validate the OHMS model and objectives.

I. INTRODUCTION

Due to improvements occurring within health care systems, longevity has increased and the age distribution of the population in industrialized countries has shifted towards older age groups. This noticeable aging will continue over the next decades.

Moreover, European Union elderly people dependency ratio is expected to increase substantially from its current levels of 25.4% to 53.5% in 2060[1]. As a result, a large number of older people will require attention on a daily bases, however they would prefer to continue living independently instead of moving to residences or relative`s home. Elderly people feel safer about their mobility if they can get help in critical situations. So, the elderly’s quality of life will heavily depend on the efficiency, comfort and safety of their home’s health care systems [2][3][4].

In order to keep the elderly’s health in an optimal status it is essential the development of effective monitoring systems. This paper presents the Oasis Health Monitoring System (OHMS), developed within the EU FP7 funded project OASIS, as a new approach for the next generation of health monitoring systems.

Nowadays, most of the remote monitoring healthcare solutions operate in a non continuous way, allowing the physician to monitor the patient’s conditions periodically, sending the measurements by asynchronous methods. Moreover, these solutions are not personalised.

OHMS allows physicians to perform continuous monitoring of the elderly, through a distributed system of personalized and synchronized XML profiles. This solution ensures that the accessed information is updated and validated in both sides of the communication channel, the elderly and physician clients, through the use of Web Service technology and OSGi architecture [4]. Thus, the information is always up-to-date in order ensure the well-being of the elderly.

The health profile is the main element used to personalise the OHMS. This profile is generated for every user, allowing the system to be more effective and to personalize the services offered to the elderly [5][6][7]. In addition, the elderly safety increase as the OHMS knows in advance possible risky situations alerting relatives and caregivers. Each profile stores valuable information of the elderly, such as the general medical history, medication schedule and the measurements taken with several biomedical off the shelf sensors with Bluetooth capabilities. Moreover, the health profile contains a pre-defined protocol in order to manage this information. Depending on the specific health condition of the user, the protocol defines a set of vital signs and activity signals that should be regularly measured and controlled, and also the ranges of these parameters in order to set the urgency of response in case of emergency, thus the OHMS reacts accordingly depending on the situation [6]. If the physician decides to change the user medication, the OHMS is able to notify users the medication changes and generate reminders at the right time [3].

The next section explains in details the materials and methods used in this project to obtain the results.

II. MATERIALS AND METHODS

The project life cycle was divided in three iterative phases (conceptualization, implementation and deployment), involving medical experts and patients at all the stages, evaluating the system in the different phases.

A. Profile description

The user’s profile is an essential part of the OHMS. Every profile stores valuable information of the elderly. According to this information, the system personalizes its behavior [5][6][7]. The information is classified as shown in Table 1.

1) General information: contains information about the

user like name, age, affiliation, phone, relative’s name, relative’s phone, reference doctor, reference hospital and other demographic information [5]. This information is entered by the elderly and the physician.

TABLE I USER PROFILE PROPERTIES CLASSIFICATION

Properties group Write Permission

Launch Alerts

Helps taking decisions

General Information

Physician and elderly

NO NO

General Health Information

Physician NO YES

Treatment, recommendations, measurements

Physician and system

YES YES

2) General health information: contains information

about the user’s health. The most important field is the health condition that describes the diseases suffered by the elderly. This property allows the system to select the adequate measurements to be taken by the biomedical sensors and the values of the thresholds that will trigger the alerts. This information is inserted by the physician.

3) Treatments, recommendations and measurements: contains information about the treatments [3], recommendations and measurements values. This group of properties is the most important. Table 2 shows the fields and the decisions taken according to the stored values.

TABLE II TREATMENTS, RECOMMENDATIONS AND MEASUREMENTS

Properties group Description Decision Medication Describes the

medication the user takes.

Reminds the user to take the medication.

Biomedical parameters

Biomedical sensors values of the last measurement taken by the user.

Triggers the control of changes that sends the alerts

Recommended measurements

Measurements the user should monitor. Also stores for each biomedical parameter the ranges of values that classify the measurement.

Decides what kind of alert should be sent.

B. Biomedical sensors

Several biomedical off the shelf sensors with Bluetooth are used to perform continuous monitoring of the elderly. These sensors measure blood pressure, heart rate, blood glucose, weight, activity, electrocardiogram and oxygen saturation. Blood pressure and ECG sensors are shown in figure 1.

Fig. 1 Blood pressure and ECG sensors

Blood pressure, weight and blood glucose sensors send the values to the user’s personal computer after the measurements are taken, while electrocardiogram, oxygen saturation and activity sensors send the values during the acquisition process. The oxygen saturation sensor is a special case. While the others get a new value every one or two seconds, this one gets more or less one hundred measurements per second. This enormous amount of information is handled carefully, to avoid the lost of out of range measurements that could generate a risk situation.

C. Vital signs classification

The vital signs measurements need to be real time treated to control risk situations and ensure the well-being of the elderly.

The vital signs classification allows the system to know which decision is the right one. This is the reason why it is necessary to set up different thresholds in order to manage the properties changes. The physician can choose the ranges among four categories:

1) NORMAL: safe situation. The measurement is correct and between the limits.

2) TO BE CONTROLLED: possible risky situation. The measurement is correct, but the user should know his health status.

3) URGENT: risky situation. The measurement is above or below the threshold and the user needs immediate attention by a medical doctor.

4) EMERGENCY: emergency situation. The measurement is completely out of and the elderly needs imminent attention by a medical doctor.

D. Profile management

The creation of an individual, dynamic and personalized user’s profile requires the collection of information explicitly or implicitly, through direct patient or physician intervention or through sensors that monitor the users’ vital signs [5].

The method applied to handle the profile information ensures two main objectives: the adequate reading and writing

and the real time assessment of the changes in the properties. The controlled reading and writing prevents simultaneous writing in one profile property, avoiding inconsistencies within the information. The real time assessment enables to control properties changes: if a critical property is modified (e.g. the elderly vital signs) the system takes the appropriate decisions according to the established protocol.

E. Profiles network communication

The Web Services are the selected tool for network communications [8][9]. Through this technology the application ensures the communication security and also the synchronization between the local profile in the user’s device and the remote one in the Profile Web service.

III. RESULTS

The OHMS system model has three different components: Profile Web Service, Profile Manager bundle and Web Service stub. All of them interact with each other, having a local copy of the XML Profile, as shown in Fig. 2.

Fig. 2 OHMS system model

A. Profile XML

The profile XML has been implemented following the profile description described previously. In order to validate the XML files created, an XML Schema has been implemented. The fields structure of the Schema is shown in Table 3.

TABLE III SCHEMA SINGLE PROPERTY STRUCTURE

Field Description

Key Property name to validate Default Default value of the property Type Type of value stored Description Description of the property

The profile XML field structure allows ensuring the main

objectives of the system. First, the Time field controls the writing and reading, avoiding inconsistencies. The values received with an old time stamp are rejected. Second, this

field also allow the system to trigger the listener when new values are received (see table 4).

TABLE IV SINGLE PROPERTY STRUCTURE

Field Description

Entry Property name Time Timestamp of the last change Type Type of value stored Value Property value

B. Profile Web Service

The system’s core is the Profile Web Service [8][9]. It is located in the server where the user’s XML profiles are stored. This web service is accessed through the “Profile Manager” OSGi bundle and the Profile Web Service stub [4]. This part of the system controls the reading and writing. Thus, the Profile Web Service ensures properties to always be up-to-date and valid.

C. Profile Manager Bundle

The Profile Manager is a OSGi bundle [4]. This component is located in the patient personal computer. This bundle allows reading and writing properties of the user profile, and also listening changes in the profile. The Profile Manager listener follows an actuation protocol. This protocol controls information changes in order to inform the user, give him advices or ensure his well-being [5]. The protocol is depicted in Fig. 3. First of all, the protocol checks if the value of the property is different from the stored one. If the value does not change no action is taken. Then, the protocol checks the type of the property (the group it belongs to). Once the system knows the property and its value, one of the next steps is followed:

1) Change recommended measurements properties: if the

health condition changes, which involve changes in the diseases the elderly suffers, other properties need to be changed as well (e.g. which measurements the user needs to take).

2) Send alert: if a vital sign is out of range the system sends an alert.

3) Send notification: changes in the profile properties should be notified to the elderly.

Values coming from the oxygen saturation sensor receive a special treatment: all the values are controlled but only relevant changes are stored in the profile (e.g. values out of range).

D. Profile Web Service stub

The Profile Web Service stub allows reading and writing properties of the user profile. This component is located in the physician personal computer. Using this web service, the physician can: notify changes in the medication,

Fig. 3 Profile Manager Actuation protocol

change the recommended measurements and receive alerts from the vital signs measurements of the elderly [8].

IV. CONCLUSIONS

This paper has presented the user’s profile management approach applied in the development of the OHMS, that is a solid tool for controlling the health status of the elderly.

This solution for managing the user’s health profile implements a distributed system of XML profiles, focusing on personalization, data security and synchronization, and thus ensuring that the stored information is always valid and up-to-date in the elderly or physician clients.

Network congestion and other problems that may arise causing reception errors have been solved through synchronized time fields within the user’s profile, providing an adequate reading and writing, and real time assessment of properties changes.

The OHMS will be tested within OASIS pilots in several European countries, where the system functionalities will be assessed in a semi-controlled environment. The outcomes of these tests will help to validate the OHMS model and objectives.

ACKNOWLEDGMENT

This work has been carried out as part of the OASIS project co-funded by the European Commission under the Seventh Framework Programme. Authors would like to thank the OASIS consortium for their valuable contribution to this work.

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