Fall Detection System
Table of Contents
Introduction
Application description
Portfolio discussion
User needs
Next Steps
Conclusion………………………………………………….
Portfolio Items and Reports
Usability test design Report…………………………………….
Portfolio item: Usability test design……………………………….
Mobile Application Security Report
Portfolio Item: Mobile Application Security………………………….
HAZOP Analysis……………………………………………..
Portfolio Item: HAZOP Analysis………………………………….
Wearable
Mobile App
Desktop
Cognitive Walkthrough Report…………………………………..
Portfolio item: Cognitive walkthrough……………………………..
Appendices
Appendix 1
High fidelity Mobile application prototype
Appendix 2
Current applications in this domain
Current relevant HCI research in the domain
Bibliography
The aim of this report is to demonstrate how our team shaped the second iteration of the design of our application interfaces. We designed four new portfolio items based on the first report. We achieved this by focusing on the usability of our design approach and by illustrating security features in addition to potential hazards. We based our approach on rigorous evaluation, as our application is a fall detection and health monitoring system for the elderly with multiple components that need to reliably work in emergency situations. The report focuses on discussing and providing reasoning for the four portfolio designs we generated as well as outlining the next steps we would take in developing the application. The sections “Current applications in this domain” and “Relevant HCI research in this domain” can be found in the appendix, as they were already included in the previous iteration.
Our application is aimed at providing functionality to wearable, smartphone and desktop platforms with the goal of responding to fall-related accidents among older adults in an efficient and timely manner, as well as, collect relevant medical information. The interaction between the different platforms is facilitated through Internet connection, as the wearable needs to send an event notification to the mobile app notifying the caregiver that there is a response needed. The caregiver then has the choice between attempting to contact the person in need, attend the accident themselves, contact the emergency services or perform all of these depending on the severity of the accident. The data collected through the use of our app on the wearable platform will also be compiled and send to a database that would be accessible by a doctor to monitor the development of the patient’s condition and would allow for pre-emptive treatment and measures to be taken before an injury or health deterioration occurs. Overall the app will aim to provide people at risk with a safety system that would ensure fast response when an accident occurs and would provide an array of information that can be used to assign better treatment and point out health issues before they become a real danger.
The four portfolio items we designed focus on maximizing usability through usability testing and cognitive walkthroughs while keeping the application secure and analyzing potential hazards within a HAZOP analysis framework.
The usability test and cognitive walkthrough both supplement the area of usability evaluation and aim to gather feedback on how to make the application interfaces as easy and reliable to use as possible. In comparison to applications used in uncritical situations, any system used in emergency conditions where seconds count is required to be as reliable and easy-to-use as possible. This is the reason behind our choice to commit two portfolio items towards the improvement in these areas.
The smart wristband as part of our application collects sensible information about its wearer, which is subsequently transmitted to the wearer’s GP doctor and to the mobile application in case of a detected fall. In addition, personal data needs to be accessed on the mobile application to provide it to EMT services in case of an emergency and to monitor a patient’s health status. As a large amount of sensible data is collected and saved, we aim to ensure a high level of security that still meets our usability criteria. Due to the critical importance of both usability and security for our application, our third portfolio item is the design of a security system, focusing on the mobile application. It aims to illustrate ways to restrict access to patient data on the mobile application and only provide it when needed in emergency situations. The challenge in this case is to provide the adequate level of security while still not hindering usability and allowing fast access.
Our fourth new portfolio item is a HAZOP analysis. It aims to supplement all areas covered thus far by looking at the whole scope of devices and people involved within our application system. It identifies hazards and provides solution proposals. We decided on using this method to get an overview of hazards for the many different components involved in our application ecosystem. This supports the idea of creating an errorless and foolproof application that is reliable. Due to the use case of our application, we consider reliability of the components a key feature towards maximum usability.
Based on the new portfolio items some of the user needs have been updated. The older adult is concerned about personal safety in case of an emergency and wants to be assured that help is imminent at all times. The caregiver has many duties and cannot watch all older people at all times, but wants to be able to provide support whenever accidents happen. In addition, they need to access personal data to monitor patients health status. Hence they would need an easily accessible and reliable emergency response system that would maintain the integrity of the system without breaching security. The doctor wants to give best possible treatment to the older persons conditions, especially concerning pre-emptive treatments, e.g. for heart attacks, so he needs as much patient data as possible.
Fall detection is a complex and evolving process, where it is essential to provide rapid assistance and prevent adverse health consequences resulting from undetected falls. There
has been an increase in the number of studies about vision-based systems, which show that their use in real-world scenarios have limitations (Igual, 2013). This is why we evaluated our system thoroughly in terms usability, security and potential hazards.
Our next steps would be implement the portfolio items we designed and statistically validate the data through the use of questionnaires. To ensure accessibility, we would conduct one more iterative evaluation of our designed interfaces by involving visually impaired users, including those who suffer from dyslexia or visual stress. Based on their feedback, we would alter our interface designs.
Subsequently, we would develop prototypes for all interfaces and set up a project plan for developing the application and its components in an agile approach. While developing the components, we would put emphasis on power consumption and privacy, as these will pose challenges regarding the performance of the system under real-life conditions.
The new portfolio items helped us gain a better understanding of how the different components can interact securely and how risks in safety critical systems affect the interaction design of our application user interfaces. Furthermore we identified core shortcomings in our design approach and how to overcome them through the addition of new features and rigorous testing.
Especially for the two interfaces of the wristband and the mobile application, usability is a key factor. As a faulty or difficult-to-use interface could potentially danger human health, an easy to use and bug-free UI is needed for the application to be reliable and actually helpful. Thus, usability in terms of HCI factors has to be tested rigorously. An approved method for effective usability tests is the use of a usability lab. This method can be considered an experiment on how to improve our applications interfaces based on feedback on user performance.
This portfolio item focuses on designing a usability test for the two critical application components of the mobile app and smart wristband with the tools a usability lab offers. The usability test is used to test the design and functionalities developed in their current state and to subsequently derive improvements to the components interfaces from the tester’s feedback.
The reason why this method was chosen is that it bears numerous advantages over other forms of generating user feedback: Firstly, a usability test identifies problems that will plague the actual users of the application effectively due to the “hands-on” approach. (Jeffries & Desurvire, 1992) This especially applies for testing the haptic interface of our wearable, which would be difficult to simulate with remote testing or questionnaires. Secondly, the high quality of the feedback generated helps minimise the risk of the finished product failing to perform according to expectations by uncovering design flaws not accounted for by the designers and developers. (Usability.gov, 2018) Due to the use of our application in emergency situations, ensuring errorless functionality is critical for its success. Thirdly, due to the environment of a usability lab, the highest possible number of KPI’s can be measured, again providing insights other methods might not be able to.
However, testing with usability labs also bears disadvantages, most importantly the high effort required to set up the test environment and the high costs to pay for the use of a usability lab and to compensate test participants. Compared to that, remote/online usability testing and questionnaires only require fractions of the effort and costs. Another disadvantage is the qualitative nature of the generated feedback, as compared to questionnaires or remote testing only small samples can be generated, which may not be valid from a statistical point of view.
For the use in our application we consider a usability test as highly useful, due to the mentioned advantages. However, for validation the results should be complemented with large data samples gained through questionnaires or other forms of feedback generation.
The expected outcome of the usability testing process is primarily to get evidence that the interfaces of the mobile app and wearable work reliably, as intended and without errors, and secondarily to gain insights on areas of improvement for the interfaces in different scenario situations, e.g. whether or not the countdown length of the wearable alarm trigger is suitable.
The application our group is designing has three different interfaces.
Elderly adults/patients engage with the application through a wearable wristband with a large button that can be used for two purposes: to trigger an emergency alarm and to stop an automatic emergency detection if there is no actual emergency. See the picture below for an approximate view of how the wristband could look like. The wristband has various sensors installed, with the purpose of monitoring the wearer’s health data and location. In addition, a sim card is included to establish a cell connection between the wearer and a caregiver monitoring the mobile app in case of an emergency.
The second interface is a mobile application, designed for caregivers to monitor if the wristband sends an emergency alert. In case of an emergency, the caregiver can initiate contact to the person wearing the wristband and, if necessary, call an EMT service to the transmitted accident location. Additionally, relevant health data recorded by the wristbands sensors can be transmitted.
The third interface is a desktop application, designed for medical doctors to analyze the health data a wristband transmits to adapt medical treatments for their patients.
The purpose of the test is to generate feedback for the following question: Are the applications interfaces suitable and errorless to allow users to execute critical application features in an efficient manner while under the stress of an emergency situation that potentially affects human health? Deduced from this, the most important KPI’s we want to measure are part of the quantitative performance measures first defined by Wixon and Wilson in 1997 (Wixon & Wilson, 1997) adapted to fit to the circumstances of our user interfaces:
To gain a statistically acceptable range of feedback, 5 test groups consisting of caregiver/patient pairs should be used. The participants should, if possible, resemble typical users, meaning actual caregivers and elderly persons. Before taking part, each participant should read and sign an informed consent form agreeing to terms and conditions of the usability test. The form should describe details of the test procedure, approximate length, compensation, information about the right to withdraw at any time, a promise of guaranteed anonymity of personal details and that the data collected is treated confidentially and not be made available to anyone other than the evaluators.
The gathered test results should be complemented with a questionnaire filled out by the participants after test completion to evaluate the perceived effectiveness of test methods and feedback on room for improvement of the usability test design and layout.
To conduct a usability test for all three components with their respective users, it is planned to use a controlled and monitored environment in the form of a usability lab with the following design specifications.
The usability lab should be equipped with technology to monitor user activity and interaction with our interfaces, specifically with video cameras and microphones recording all scenarios, screen-tap and eye-movement logging for the mobile application and mirrored window for members of the project team to watch the test without distracting the participants. In addition, a soft gym mat or a similar object on which it is safe to fall for humans should be provided for the participant testing the fall-detection of the wearable interface and its reliability.
The following scenarios should be tested in the usability lab:
Firstly, the scenario of a patient falling and the wristband recognizing this and starting a countdown after which an alarm would be sent to the mobile app monitored by a caregiver. However, the patient is able to help themselves and does not need further support, so they cancel the alarm.
Secondly, a scenario similar to the first one, with the difference that the patient does not cancel the alarm countdown this time, due to being unconscious or acknowledging they need help. As a result, the wristband establishes voice communication to the mobile app, allowing the caregiver to speak to the patient and see relevant health data to assess whether an ambulance is needed or not. In this scenario, it is assumed that an ambulance would be needed, so the caregiver subsequently initiates contact to EMT services, providing them with all relevant information via phone.
Thirdly, a scenario where an alarm is triggered by the wristwatch and communication established with the caregiver. This time however, the patient is able to help themselves out of the situation by following instructions given by the caregiver through the established phone connection.
Throughout history usability and security have always been considered as trade offs when designing any user centered system. UX designers had specific job requirements to design and implement human computer interaction systems that favored usability while the security expert is brought on in later stages to make systems more secure. However, with advancements in both HCI systems and security attacks the two job requirements have merged. The system must be secure enough to protect the user’s data but not too secure that the user cannot access the system. The system we aim to design will need to have a very high usability standard since it is an emergency response system and time is of the essence when accessing the mobile application. However the wearable device will be collecting data about the patient at all times and the system will have to be secure enough to keep the patient’s data private and only accessible to the appropriate user. Hence, we chose to dedicate this portfolio item to security. We revisited the mobile application prototype (Appendix 1) to evaluate it and improve the design by applying techniques that were found in various academic sources.
Kobie (2016) argues that the relationship between the two components does not have to be a trade off. He quotes Justin Hevey “Security needs to be embedded into sprints in planning, design and implementation phases,” The approach that helps bridge the gap between the two concepts while maintaining the integrity of the system is called Security by Design, which is “…the premise that security should be built in earlier in the development process, rather than awkwardly tacked on at the end” (Kobie, 2016). Therefore the security expert of any project should be involved in every stage to ensure that there are no attack vectors in the system.
Furnell (2016) also believes that today’s technology has evolved enough for the two components to coexist without damaging the integrity of any system. He explains how “devices have advanced […] through the use of biometrics, with significant examples including the arrival of face unlock on Android and Touch ID on iOS devices… they have made security easier and more friendly and thus increased the chances of it getting used.”
Thus, we decided on using the Security by Design and biometric authentication for our system. We expect that the ratio between usability and security will be balanced. Therefore the users will be able to use the mobile application without any inconvenience while keeping the patient’s data secure.
Through the mobile application the caregiver can access two main components of the Fall Detection system. The first one is the emergency response component which allows the caregiver to respond in case of a fall being detected. The second one is the data analysis component, a section where the caregiver can monitor the patient’s medical status at any point in time. The most important feature of our system is the emergency response mechanism; hence we came to the conclusion that the security of the system should not hinder the user while responding to any kind of emergency.
In an event of a fall being detected by the wearable device, an alert is triggered; we will have minimal but reliable security on the mobile application. If the caregiver is using a mobile phone with biometric accessibility, for example fingerprint scan or facial recognition the system will allow the user to use a biometric authentication to respond. For example the caregiver responding to the alert would be able to scan their fingerprint and quickly access the mobile application to respond.
The sequence of events would go as follows:
However if the caregiver has a mobile phone with no biometric capabilities then password protection would be necessary, and the sequence of events would change to:
In an event where the immediate caregiver would need to access the patient’s data to monitor their medical status at any given time the system would require an extra security layer. Once the caregiver is navigating through the application and he/she wants to access the data section, they would need to provide a password for full access.
In a system such as ours, which deals with potentially life-threatening circumstances, performing a risk analysis is crucial for a thorough design evaluation process. As expected it provided us with many ideas on how to improve our system and what features need to be added to improve usability and security. Thus, we performed a HAZOP risk analysis on our user interface design for each platform.
There are various methods to conduct a risk-assessment evaluation. Hazard Analysis was considered too broad and general for our purposes with its top-down approach (Hussey and Atchison, 2000). PHEA was attractive at first as it would focus on the mistakes of the users of our system and would allow us to consider the different steps in the HTA analysis that we presented in our previous report and the possible mistakes that the users could make while interacting with our system. Eventually we decided to adopt the HAZOP method as a middle ground between the user-centric PHEA and the top-down nature of Hazard Analysis. HAZOP provided us with the whole spectrum of possible risks that our system can face and proved to be especially helpful in developing new features. By adopting a systemic examination of risks and tasks in the form of HAZOP, we expect to identify weak points in our system and put in steps to alleviate the dangers of these occurrences taking place.
We used the collective brainstorming intended by HAZOP to develop scenarios with the help of a great variety of keywords at first which were later narrowed down to six. The standard version of HAZOP was used because we did not look at risks that can develop simultaneously to test the safeguard developed through the analysis or added graphical representation of risks’ likelihood (Herrera et al, 2015). For the purpose of this assignment we are going to leave out some of the later steps of HAZOP where risks are given a time-frame to be addressed (PQRI, 2015).
The discovery of deviations allowed us to gain a better understanding of the issues that can surround our system and made us aware of many of the possible risks that our application can be subjected to due to a fault in the equipment, incorrect use of the system and factors outside the interaction between it and the user. Our study is separated into 3 sections based on the part of our system. This means that there is a separate table for the wearable user-side of the system, one for the mobile app and one for the desktop version used by the doctor.
One drawback of the HAZOP analysis is that it looks at risk events individually rather than at a combination of them, which can limit the predictability of more complex issues. In addition, HAZOP does not deal with quantitative data as it determines the heuristics of the possible events that can lead to hazardous situations (Baybutt, 2015). In later stages, when we have more detailed prototypes, collating statistical data points from experiments can provide us with more practical data as to what to expect when the system goes live.
Key words: Incorrect, Undelivered, No, False, Overflow, slow
| Item | Guide Word | Deviation | Causes | Safeguards | Consequences | Actions |
| 1 | Communication | No Communication; | No battery charge; |
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