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Designing Content-driven Intelligent Notification Mechanisms for Mobile Applications


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An increasing number of notifications demanding the smart-phone user's attention, often arrive at an inappropriate moment , or carry irrelevant content. In this paper we present a study of mobile user interruptibility with respect to notification content, its sender, and the context in which a notification is received. In a real-world study we collect around 70,000 instances of notifications from 35 users. We group notifications according to the applications that initiated them, and the social relationship between the sender and the receiver. Then, by considering both content and context information, such as the current activity of a user, we discuss the design of classi-fiers for learning the most opportune moment for the delivery of a notification carrying a specific type of information. Our results show that such classifiers lead to a more accurate prediction of users' interruptibility than an alternative approach based on user-defined rules of their own interruptibility.
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Designing Content-driven Intelligent Notification
Mechanisms for Mobile Applications
Abhinav Mehrotra
University of Birmingham, UK
Mirco Musolesi
University of Birmingham, UK
University College London, UK
Robert Hendley
University of Birmingham, UK
Veljko Pejovic
University of Ljubljana, Slovenia
An increasing number of notifications demanding the smart-
phone user’s attention, often arrive at an inappropriate mo-
ment, or carry irrelevant content. In this paper we present a
study of mobile user interruptibility with respect to notifica-
tion content, its sender, and the context in which a notification
is received. In a real-world study we collect around 70,000 in-
stances of notifications from 35 users. We group notifications
according to the applications that initiated them, and the so-
cial relationship between the sender and the receiver. Then,
by considering both content and context information, such as
the current activity of a user, we discuss the design of classi-
fiers for learning the most opportune moment for the delivery
of a notification carrying a specific type of information. Our
results show that such classifiers lead to a more accurate pre-
diction of users’ interruptibility than an alternative approach
based on user-defined rules of their own interruptibility.
Author Keywords
Mobile Sensing; Notifications, Interruptibility,
Context-aware Computing.
ACM Classification Keywords
H.1.2. Models and Principles: User/Machine Systems; H.5.2.
Information Interfaces and Presentation (e.g. HCI): User In-
An increasing number of smartphone applications actively
push information to the users. These services provide noti-
fications about a variety of events, such as the arrival of an
email, a new comment on a social network post, or a system
update. Proactive services are indeed beneficial to the users,
facilitating task switching and opening a number of informa-
tion channels. However, due to the pervasive nature of smart-
phones, notifications often arrive at inconvenient moments.
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Psychological studies have found that initiating interactions
at inopportune moments can become a source of interrup-
tion [22, 32]. Such an interruption can adversely affect task
completion time [8, 9, 23], error rate [5], and affective state
of the user [3, 4]. Consequently, mobile notifications have a
potential to drive smartphones away from Mark Weiser’s vi-
sion of calm computing [30], which advocates “disappearing”
technologies completely blended into our daily lives.
The interaction of a user with mobile notifications is indeed
extremely complex and depends on numerous aspects. For-
tunately, some of the aspects can be captured, and above all,
quantified, by means of the embedded sensors that modern
smartphones are equipped with. These sensors allow a mobile
application to collect information about the user’s day-to-day
activities [7, 21], preferences [31], and the surrounding en-
vironment [19]. Past studies have used some of the sensed
information to infer opportune moments, i.e., moments in
which a user quickly and/or favorably reacts to a notifica-
tion [10, 24]. More specifically, some important contextual
factors that have been used to infer interruptibility include
transitions [15], engagement with a mobile device [10], and,
more generally, time of day, location and activity [24].
However, until now, the focus has been on the context in
which a notification has been received and not on the actual
content of the notification. After all, not all the notifications
are disruptive [20]. It is the relevance of the interruption con-
tent in the recipient’s current context that partly defines the
disruptiveness of an interruption. For example, a chat notifi-
cation from a friend can be extremely disruptive if delivered
during a meeting. But, an email notification from a project
collaborator might be acceptable to the user, and in some
cases, considered very useful in the same context.
In this work we discuss how content and context can be used
together in order to design intelligent non-disruptive notifica-
tion mechanisms. More specifically, we investigate how users
behave when they receive specific types of content through
mobile notifications arriving at different times, and in differ-
ent contexts. Unlike previous studies such as [24], we do not
restrict ourselves to context information provided by mobile
sensors only. Instead, to the best of our knowledge, for the
first time we also take into account the type of information
delivered and the social relationship between the information
sender and receiver. It is worth noting that our work is predi-
cated on the hypothesis that the acceptance of a mobile noti-
fication depends on what, e.g., the type, and the origin, of the
information contained in a notification and where, the user’s
context in which the notification is delivered. We will con-
sider a notification as accepted if it is handled (i.e., clicked to
launch the respective application) by the user within a certain
time of its arrival.
In order to test our hypotheses, we collect mobile notifica-
tions of 35 users for a time period of three weeks. We analyze
these notifications to understand the key features that deter-
mine their acceptance. To the best of our knowledge, this is
the first study to use notifications collected “in the wild" for
such an analysis.
The outcome of our analysis can be summarized as follows:
User’s acceptance of a notification depends on the content
and the originator of the notification and, not surprisingly,
the time needed to respond to a mobile notification varies
according to the user’s physical activity level.
Notification content, together with the sensed context, can
serve as a basis for the design of machine learning classi-
fiers that infer a user’s response to a notification.
Automated inference of opportune moments to interrupt,
as with the above classifiers, outperforms subjective rules
with which our subjects described their interruptibility.
The inference of a user’s interruptibility can be performed
locally, in an online fashion, achieving a stable state (i.e.,
more than 60% precision) after nine days of training.
We conclude that inferring the right moment for interruption
should be done in a holistic manner, jointly taking into ac-
count the context of the recipient, and the notification con-
tent. We show that a prediction model trained on a user’s per-
sonal data performs far better than a generic prediction model
trained on multiple users’ data. Finally, we point out the im-
portance of an automated approach, as humans remain ineffi-
cient at formalizing and communicating their preferences for
mobile notifications in terms of predefined rules.
Mobile phones represent a great platform to increase the im-
pact of information by delivering it in real time. At the
same time, mobile notifications allow the users to be aware
of newly available information. However, the wrongly timed
notifications come with a cost of interruption to the on-going
task [5]. This can cause negative emotions, reduce the value
of the application from which such a notification was trig-
gered. For example, the perception of a mobile marketing
message, and, consequently, the whole brand that is being
advertised could be impacted by the moment in which a mes-
sage arrives [14, 27]. Thus, in order to provide the best value
of information to the user, it becomes a necessity to deliver
notifications at opportune moments.
What Defines an Opportune Moment?
In [6], Clark suggest that a user can respond to an interruption
in four possible ways:
1. handle it immediately;
2. acknowledge it and agree to handle it later;
Figure 1. NotifyMe application screenshots.
3. decline it (explicitly refusing to handle it);
4. withdraw it (implicitly refusing to handle it).
The first two categories of responses suggest that the inter-
ruption content is acceptable to the user. However, the second
type of response indicates that the interruption content is not
relevant at the moment of its delivery and, thus, it should have
arrived after a certain time delay in order to be handled imme-
diately. On the other hand, the responses with a decline and
withdraw reflect that the interruption is not at all acceptable
to the users.
We construct our hypothesis based on these possible re-
sponses of a user to an interruption. We hypothesize that a
moment is opportune to deliver a notification only if the user
handles the notification immediately. This does not mean that
an intelligent interruptibility management system should just
try to reduce the response time, it should also aim to increase
the acceptance rate of notifications.
How to Predict an Opportune Moment?
Sahami et al. [28] demonstrated that the notifications trig-
gered by applications from various categories are given differ-
ent importance by users. At the same time, Pielot et al. [26]
claimed that the user response is influenced by social pres-
sure. This suggests that the user’s decision about how to re-
spond to a notification is made after looking at the notification
title which gives a clue about the information contained in it.
On the other hand, Grandhi et al. [12] suggested that by just
relying on sensor based knowledge, interruption management
systems often fail to infer whether the interruptions are dis-
ruptive or not because they do not take into account the sender
of an interruption and the information that is being sent.
Thus, it is better to predict an opportune moment to deliver a
notification by considering both notification content and the
context in which it is delivered. To better understand the def-
inition of opportune moments, let us consider a scenario in
which a person at her workplace receives a notification re-
garding the arrival of an email from a colleague working on
the same project and, separately, a new comment on one of
her social networking posts. Given the circumstances, the
user accepts the email notification leaving the social network-
ing notification unattended. Later, on the way home, the user
clicks on the social networking notification to read the new
Feature Description
Arrival time Time at which a notification arrives in the
notification bar.
Removal time Time at which a notification is removed from
the notification bar.
Response time Difference between arrival and removal time.
Whether the notification was clicked or not
Sender application Name and package of an application which
triggers a notification.
Notification title Title of a notification displayed in the
notification bar.
Alert type Signals used to alert the user for a notification:
sound, vibrate, and LED.
Physical activity Current activity of a user.
Location Current location of a user.
Surrounding sound Whether the user is in a silent environment or
not (boolean).
WiFi connectivity Whether the phone is connected to a WiFi or
not (boolean).
Proximity Whether the user was proximate to the phone in
the last one minute or not (boolean).
Phone’s status Whether the phone was in use in the last one
minute or not (boolean).
Ringer mode Current ringer mode: sound, vibrate and LED.
Table 1. Description of features from the NotifyMe dataset.
In this scenario, since only one notification was read while the
other was unattended, it is impossible to decide whether the
sending moment is an opportune moment or not by using only
the context of the user. Both notifications arrived at the same
moment but were accepted in different contexts. It is the no-
tification content that enables the recipient to decide whether
to accept it or not in the current context. Thus, the notifica-
tion content and the user’s context together play an important
role in identifying an opportune moment to deliver a notifi-
cation. However, for privacy reasons it might not be feasi-
ble to exploit the content of notifications because they might
contain extremely sensitive information1. Therefore, we pro-
pose using the notification title that contains more high-level
and abstract, but at the same time, useful information about
the category of information contained in the message itself.
More specifically, the title can be used to classify the category
of a notification. In addition, we capture a series of attributes
about the user’s physical context as well as the phone settings.
These content and context data are then used to build a pre-
diction model to predict the acceptance of a notification. The
study was done in accordance with our institution’s ethical
research procedures, and all the participants were volunteers
who provided their consent to collect data. The consent form
itself for the data collection application was reviewed by the
Ethics Board of our institution.
In order to study the influence of context and content on user
response, we collected in-the-wild notifications from a set of
users. More specifically, we developed an Android app called
1We are aware that a large number of companies offering services
such as social networking actually perform text processing from
user-generated content. This type of analysis might not be possi-
ble in an academic context, and in any case, it raises significant pri-
vacy issues, especially for testing and validating the findings against
ground-truth data, since the researchers have to access to the original
text itself.
Question Options
How would you rate the
notification content?
Likert scale rating between 1
and 5 (1 = very annoying and 5
= very interesting).
Where would you like to receive
notifications with similar content?
Home, workplace, other,
anywhere and I don’t want.
When would you like to receive
notifications with similar content?
Morning, afternoon, evening,
night, anytime and never.
How are you feeling? Happy, sad, bored and annoyed.
Are you busy? Yes and no.
Where are you? Home, workplace, public, other.
Table 2. Questions and their options from NotifyMe questionnaire.
NotifyMe that runs in the background to unobtrusively mon-
itor notifications and the context in which they are posted. It
relies on Android’s Notification Listener Service [1] to trace
notifications, and uses Google’s Activity Recognition API [2]
and ESSensorManager [17] to obtain the context information.
Table 1 lists the description of features captured by NotifyMe.
It is worth noting that the Alert Type indicates the signals used
by a notification to alert the user, whereas the Ringer Mode
refers to the phone’s ringer mode settings.
To infer the user response to a notification, NotifyMe checks
whether the application that triggered the notification was
launched after the removal time of that notification. Since
most of the notifications are triggered by chat and email ap-
plications, users usually click on such notifications to read the
full text and reply. Therefore, we assume that users click on
the notifications that arrive at opportune moments. We are
aware that our approach has limitations, because some noti-
fications, which do not require further action, might not be
clicked rather just seen and dismissed by the user.
Additionally, every day NotifyMe posts 12 notifications
on the user’s smartphone containing information that is
randomly chosen from breaking news, weather update, and
Facebook likes. These notification are triggered randomly
every hour between 8.00 am and 8.00 pm. In this way we
generate a consistent set of notifications for our analysis over
all the users and we enhance the richness of the categories
of information received by them. Furthermore, NotifyMe
also collects subjective data from its users by triggering six
questionnaires each day. A questionnaire comprises of six
multiple-choice questions. Each questionnaire is triggered
randomly in every two hours time window between 8.00 am
and 8.00 pm. When the users are busy, NotifyMe allows
them to decline the questionnaire notification by simply
remove it from the notification bar; moreover, the application
makes sure that it does not trigger another questionnaire for
the next 30 minutes. The list of questions, along with the
options included, are shown in Table 2.
Recruitment of the Participants
NotifyMe was published on Google Play Store and advertised
at our University. It was installed by 35 participants without
any monetary incentive. These participants come from both
sexes, with the age span between 21 and 31 years. As shown
in Figure 1, NotifyMe allows users to check the number of in-
stalled applications for each category and a bar graph of their
notification acceptance rate for each hour of a day. We believe
that displaying this information has a minimal interference on
users’ actual behavior in terms of notification acceptance, yet
presents a valuable stimulus to make the users keep the app
installed on their phones.
Ensuring Privacy Compliance
In order to allow the NotifyMe application to monitor notifi-
cations, the user has go give explicit permission as required
by the Android operating system. Moreover, the application
also shows a detailed user consent about the information that
is collected. This ensures that the user is aware of the type
of information captured by the application. Furthermore, we
use notification content only to classify the category of infor-
mation that a notification contains because such data can have
severe privacy implications. We only store the notification’s
content category and discard the raw notification information.
The data collection was carried out for a time period of 3
weeks from 35 users who installed the NotifyMe applica-
tion. Overall, we collected more than 70,000 notifications
and around 4,069 responses to questionnaires. Since, our ob-
jective is to predict the probability of the notification’s accep-
tance by using a notification’s content category and the user’s
context in which it is delivered, we classify the collected no-
tifications according to the type of information they contain.
In order to classify a notification, we use the approach of
mapping the notifications to the category of application from
which they were triggered. The categories defined by the
Google Play Store are too generic and no previous work has
made any such list publicly available. Therefore, we manu-
ally categorize the applications from which the notifications
were triggered.
Around 70% of the data set comprises of notifications trig-
gered by chat and email applications. Since these two noti-
fication categories dominate over the combined notification
counts of all the other application categories, we could not
rely solely on the approach to classify notifications based on
the category of applications with which they were triggered.
Thus, we split chat and email notifications in the following
four sub-categories based on the sender’s relationship with
the recipient of a notification:
1. Work: sender works or studies with the recipient;
2. Social: sender has a social tie with the recipient;
3. Family: sender is the recipient’s family member or relative;
4. Other: sender not related to the recipient with the above
In practical applications, this information might be extracted
from social network platforms and/or inserted directly by the
users (see also Discussion section). We believe that this
methodology can be generalized: more fine-grained or dif-
ferent classification might also be possible.
We rely on the title of communication notifications in order
to classify them in the above four classes. A communica-
tion notification’s title comprises of the sender’s name along
Figure 2. Percentage of notifications for each category and sub-category.
The sub-categories are derived by using the recipient’s relationship with
the sender.
with a short description about the newly available informa-
tion (such as "A new message from Alice", and "Alice sent
you a new message"), or only the sender’s name (such as "al-" or "Alice"). However, a few communication
applications do not disclose any information about the sender
in the notification title but only includes the description about
the newly available information (such as "1 new message")
or the application’s name itself (such as "Telegram"). There-
fore, we use the notifications that contain the sender’s infor-
mation in their title and discard the rest of the communica-
tion notifications. We then generate a list of unique titles2
from the communication notifications of each participant and
give these lists to their owners. We ask the participants to
label each notification title with the following classes: work,
social, family, and other. Participants were asked to provide
multiple labels in case they have multiple relational links with
the sender of a notification. For example, a colleague can also
be a friend of a user, and an email from a job portal can be
considered as both work and other.
Finally, we map the user-defined labels to the notification that
owns the respective title. Since, there were a few notification
titles that were labeled with multiple classes: 1) work and
social, and 2) social and family, we choose a category based
on the location in which the notification arrived. For example,
if a notification that is labeled as both social and work, arrives
at their workplace we consider it as a notification containing
work related information. We define a category probability
list for each location from our data and look for a label that
has the highest value at the location in which the notification
was triggered. The category probability list for each location
is defined as follows:
1. Workplace: work, social, family;
2. Home: social, family, work;
3. Other: family, social, work.
Note that in order to infer these three location classes we sam-
ple GPS when a questionnaire is answered. We assign the la-
bel for the current location provided by the users as an answer
to a question "Where are you?" in the questionnaire, to the
sampled geo-coordinates. Since the location labels provided
2In order to avoid the users from labeling a title multiple times, we
create this list containing notification titles without any duplication.
0 5 10 15 20 25 30 35 40 45 50
Response Time (min)
Figure 3. CDF of response time for notifications.
by the users do not include any public location label, we ex-
clude this location class. Additionally, we reverse geo-code
the home address provided by the users at the time of regis-
tration and validate user-defined labels for these locations.
Out of 35 participants only 17 participants opted to label their
communication notifications’ title as discussed above. All
of these participants continued to run NotifyMe application
and actively responded to the questionnaires for at least 15
days. Therefore, in order to perform notification category-
based analysis, we use around 25,000 notifications and 1,450
questionnaire responses of the participants who opted to la-
bel the communication notifications’ title. Figure 2 shows the
percentages of notifications that belong to each fine-grained
In this section we provide evidence that the content and con-
text play an important role in influencing the response time
and acceptance of a notification.
Time Delay in Response to a Notification
As discussed earlier, an intelligent interruptibility manage-
ment (IM) system should define a moment as opportune to
deliver a notification only if the user handles the notification
in a given time interval. Therefore, it becomes necessary to
define a threshold for time delay in response to the notifica-
tions by the users. The notifications that are responded to
after this threshold will be classified as delivered in an in-
opportune moment. This approach is based on the strategy
employed by the previous study [26] that predicts whether a
user will view a message within the assumed threshold time.
We analyzed the complete dataset of notifications (containing
around 70,000 notification samples) to draw a picture of the
general response time for all notifications. Note that a noti-
fication is considered responded to when it is removed from
the notification bar.
As shown in Figure 3, more that 60% of the notifications
were clicked within 10 minutes from the time of arrival. The
density of notifications increases with a high rate up to 10
minutes and after 10 minutes the rate starts stabilizing. This
demonstrates that users handle most of the notifications by
either clicking or dismissing them within a 10 minute pe-
riod. Also, users do not interact with the notifications for a
0 5 10 15 20 25 30
Response Time (min)
On Foot
On Bicycle
In Vehicle
Figure 4. CDF of response time for notifications received while perform-
ing different activities.
long time if they are not handled within 10 minutes. Overall,
we can conclude that in general the maximum response time
taken by a user to handle notifications that arrive at opportune
moments is 10 minutes. However, it might vary according to
the user’s behavior. Therefore, in this study we choose 10
minutes as the threshold time delay for responding to a no-
tification. At the same time, the goal of this analysis is not
strictly dependent on the choice of this specific value. In other
words, the aim is to provide a general design methodology for
intelligent content-driven notification systems.
It is also worth noting that there is a sharp increase in the
number of responses at around 30 minutes after the arrival.
This is because some applications kill their notifications that
do not get any response from the users up to a certain thresh-
old. Our dataset shows that more than 70% of the notifica-
tions which were removed from the notification bar between
29 and 31 minutes were triggered by Google Now.
Impact of Context on Response Time
In the collected data we see that the notification response time
can vary from a few seconds up to some hours. A notification
delivered at an opportune moment might be responded to very
quickly, but a notification can have a greater time delay if it
arrives at an inopportune moment. We analyse the complete
dataset of notifications to find the context modalities (i.e., the
attributes of a user’s context such as location, activity and
others) that could indicate the response time for a notification.
We evaluate the response time of notifications with respect
to three context modalities: location, activity, and surround-
ing sound. We find that the average response time of a no-
tification does not vary with the user’s location (i.e., home,
workplace, and other) or the surrounding sound (i.e., silent or
speaking). However, the data shows that the activity of users
does impact the response time of notifications.
We rely on Google’s Activity Recognition library [2] to clas-
sify a user’s activity into four classes: 1. still – when the user
is not moving; 2. on foot – when the user is either walking or
running; 3. on bicycle – when the user is riding a bike; 4. in
vehicle – when the user is travelling in a vehicle.
As shown in Figure 4, users are very quick to respond to no-
tifications while they are traveling in a vehicle. Around 80%
Notification Click Count (%)
Figure 5. Click count percentages for the notifications of each category.
of the notifications that arrived while the user was in a vehi-
cle were responded to within 10 minutes. At the same time,
when the users are still, walking, or running they tend to re-
spond to almost around 60% of the notifications within 10
minutes. It is worth noting that the response rate gradually
becomes flat after 10 minutes in all of these three cases. On
the other hand, the activity of riding a bike is associated with
inopportune moments to deliver a notification.
Impact of Content on Notification Acceptance
In this subsection we analyze the impact of the content on the
acceptance of notifications. Since we are interested in the ac-
cepted notifications, we classify all the notifications with the
response time greater than the threshold time (i.e., 10 min-
utes) as declined notifications.
In Figure 5 we evaluated the average percentage of the noti-
fications that are accepted in a day for each notification cate-
gory. The results demonstrate that the notifications from dif-
ferent categories have a varying acceptance rate. The family
chat and work email notifications have the highest acceptance
rate with around 81% and 77% of the notifications accepted
within 10 minutes of arrival time, respectively. On the other
hand, notifications of categories such as system, tools, and
music and media, have the worst acceptance. Around 10% of
the overall notifications in the dataset of labeled notifications
belong to the tools category (see Figure 2) but around 99%
of the time these notifications were declined by the users.
This demonstrates that such notifications almost never pro-
vide useful information at the right time to the users and in-
stead become a source of disruption.
It is worth noting that the event reminder notifications might
have a low acceptance rate because 1) these notifications pro-
vide almost all the information in the notification title; 2)
these notifications enable the user to snooze, or delete the re-
minder through the notification itself without launching the
application. For this reason it becomes difficult to capture the
response of a user for an event reminder notification.
In this section we test our hypothesis: that the acceptance
of a mobile notification relies on the type of information in
it and the user’s context, by analysing the labeled dataset of
collected notifications.
Feature Rank Average IG
App Name 1 0.251
Notification category 2 0.247
Phone status 3 0.092
Location 4 0.081
Arrival hour 5 0.073
Ringer mode 6 0.056
User’s activity 7 0.042
Priority 8 0.026
Alert type 9 0.024
Proximity 10 0.017
Surrounding sound 11 0.003
WiFi connectivity 12 0.001
Table 3. Ranking of features from the NotifyMe dataset.
Data Setup
As the response time of notifications can be very large if they
are delivered at the inopportune moments, it contrasts with
our objective of finding the opportune moment to deliver a
notification that will be handled immediately. Therefore, we
label all notifications which were accepted within the thresh-
old response time (i.e., 10 minutes) as "accepted" and the rest
as "declined".
Feature Ranking
To understand the value of these features, we rank each fea-
ture based on the information gained by adding it for predict-
ing the notification acceptance. We use the InfoGainAttribu-
teEval method from WEKA [13] to derive the information
gain (IG) each of the attributes brings to the overall classifica-
tion of a notification as accepted or declined. Table 3 shows
the average ranking of the features. The feature evaluation
used 10-fold cross validation. Our results show that the name
of the application from which a notification is triggered and
the notification category are the most important features.
Building Prediction Model
We build individual-based models for predicting notification
acceptance by using three different algorithms: Naive Bayes,
AdaBoost, and Random Forest. We use two approaches for
building prediction models: 1. Data-driven learning that relies
on the evidences rather than personal intuitions; 2. User-de-
fined rules that rely on the user’s own intuitions.
Data-driven learning
The data-driven learning relies on all the features about the
notifications that are collected via the NotifyMe application.
As discussed earlier, we derive the category of a notification
by using the type of information in it and the recipient’s re-
lationship with the sender. However, in order to evaluate the
value of using the information type and social circle, we build
the prediction models in three ways:
1. without using information type and social circle;
2. using only information type;
3. using information type and social circle.
To build a prediction model in the first and third ways, we
simply excluded and included the "category" feature respec-
tively while training the algorithms. However, in order to
Naive Bayes AdaBoost Random Forest
Sensitivity (%)
Naive Bayes AdaBoost Random Forest
Specificity (%)
With User-defined Rules
Without Using Information Type and Social Circle
Using Only Information Type
Using Information Type And Social Circle
Figure 6. Prediction results of the predictors trained by using 3 different set of features for data-driven learning and user-defined rules.
train a predictor in the second way, we use modified "cate-
gory" feature that is derived by using only the information
type. For example, work email was labeled as email, and so-
cial chat was labeled as chat.
User-defined Rules
The user-defined rule-based learning relies on users’ re-
sponses to the questionnaires triggered by NotifyMe appli-
cation. We collected 1456 questionnaire responses from the
17 users. The analysis of these responses shows that users
are not consistent in defining the rules for the delivery of no-
tifications. Therefore, we used the following 3 features from
each questionnaire response (see Table 2) to build a predic-
tion model:
1. notification category for which the questionnaire was trig-
2. best location where the user wants to receive notifications
with similar content;
3. best time when the user wants to receive notifications with
similar content.
The features in each questionnaire contributed to a rule for
acceptance of a category of notifications. For example, a
questionnaire response by a user containing "social chat" as
content category, "home and other" as the best location, and
"morning" as the best time defines that all social chat notifi-
cations that are delivered in the morning when the user is at
home will be clicked. Otherwise, the social chat notifications
will not be clicked by the user.
Evaluating the Predictors
We evaluate the data-driven prediction models by using the
k-fold cross validation approach with the value of k as 10. To
evaluate the prediction models for user-define rules, we use
all notifications of the respective users. Figure 6 shows the
sensitivity and specificity of all the predictors. The sensitivity
refers to the proportion of actual positives which are correctly
identified (i.e., number of notifications that are correctly pre-
dicted as accepted / number of notifications that are actually
accepted). On the other hand, the specificity refers to the
proportion of actual negatives which are correctly identified
(i.e., number of notifications that are correctly predicted as
declined / number of notifications that are actually declined).
Our results demonstrate that there is no significant difference
in the performance of the three prediction algorithms. The
user-defined rules do not perform well as compared to the
data-driven learning. The user-defined rule-based predictors
only achieve the sensitivity of 55% and specificity of 45%. A
possible explanation is that the user preferences change with
time. For example, a user might specify that she wants to re-
ceive social chats only in the morning, but on the next day
she might specify another time period for the same category
of notifications. This is a reason why the predictors for user-
defined rules perform differently. Moreover, users can define
very abstract rules as compared to the complex rules created
with the data-driven approach by using numerous other fea-
As we trained the data-driven predictors with different fea-
tures, the results show that the predictor trained with "in-
formation type and social circle" indeed outperforms all the
other predictors. The predictor trained with "information type
and social circle" achieves the sensitivity equal to 70% and
the specificity up to 80%. Its specificity remains slightly
lower than the specificity of the other two data-driven pre-
dictors, but far better than the predictor trained by using user-
defined rules. It is because of the trade-off between sensi-
tivity and specificity. Thus, the predictor using the "infor-
mation type and social circle" feature attains high sensitivity
by loosing some specificity. It is worth noting that the user
preferences change with time. Therefore, by including the
noisy features from the user-defined model, the accuracy of
the data-driven predictor will definitely go down.
However, the aim of an interruptibility management system
is not only to reduce the disruptive notifications (i.e., high
specificity), but also to provide the notifications that are re-
quired by the user. This suggests that the use of information
type and the recipient’s relationship with the sender can boost
the performance for predicting the interruptibility. It is worth
noting that for some users the sensitivity value went to around
89%. This demonstrates that some people follow their regular
behavioral pattern. The predictions for the behavior of such
users can be very accurate due to minimal uncertainty in their
behavioral patterns.
In this section we compare the performance of the prediction
models trained on a user’s personal data with a generic pre-
diction model trained on multiple users’ data. We build both
individual-based models and a generic model for predicting
Naive Bayes AdaBoost Random Forest
Sensitivity (%)
Naive Bayes AdaBoost Random Forest
Specificity (%)
Generic Model
Personal Model
Figure 7. Prediction results of the generic and individual-based models.
notification acceptance by using three different algorithms:
NaiveBayes, AdaBoost, and Random Forest. We trained the
data-driven models in the same fashion as discussed in the
earlier section. We evaluate the individual-based models by
using the k-fold cross validation approach and the generic
model with the entire set of notifications of each user.
As shown in Figure 7, the individual-based model outper-
forms the generic model with a very high difference of sen-
sitivity value. At the same time, the generic model achieves
extremely high specificity (i.e., around 95%) because it gets
trained with most of the rejected notifications in different con-
texts. Thus, the generic model predicts most of the notifi-
cations as declined. An interruptibility management system
using such a prediction model will mostly not allow any no-
tification to be triggered. This will be same as switching off
the phone which ensures no notification is triggered, but also
takes away the benefit of receiving relevant notifications. This
demonstrated that a prediction model trained on a user’s per-
sonal data is more accurate for predicting interruptibility of
that user than a generic prediction model trained on multiple
users’ data.
The predictors discussed in the previous section were geared
towards batch learning in which the models are trained with
the static data. Such an approach has two key drawbacks
when used on mobile phones. First, the data becomes avail-
able gradually as the new notifications arrive and, there-
fore, a personalized model cannot be trained until a sufficient
amount of data is available. Second, the prediction accuracy
can be dramatically reduced when a user changes his/her be-
havioral pattern. Moreover, data are not usually available for
new applications installed by users. For example, when a user
starts using a new email client or a social networking appli-
cation, the model might fail to make any accurate predictions
for the notifications triggered by these applications.
To overcome these drawbacks we can use the online learning
approach in which the models are regularly trained with the
newly available data. Such an approach enables relatively fast
learning for new applications (i.e., predictions can be made in
the initial days), adaptation to changing or new behavior; and
improvement of the performance over time (i.e., the average
prediction accuracy can be enhanced gradually as more and
1 2 3 4 5 6 7 8 9 10 11 12 13 14
Precision (%)
User-defined Rules
Random Forest
Naive Bayes
Figure 8. Prediction results of different predictors using online learning
more data becomes available, in case the behavioral patterns
do not show strong variations over limited amount of time).
We use our labeled dataset to demonstrate the prediction ac-
curacy of different algorithms by using the online learning ap-
proach. We iteratively build all the prediction models with the
notification data collected by the end of each day and evaluate
these models by using notifications of the following day. For
example, on day N a model was built by using notifications
from day 1 to N and it was evaluated to predict the acceptance
of notifications that arrived on day N+1. Similarly, we train
the models for user-defined rules by using questionnaire re-
sponses of respective users collected by the end of each day,
and evaluate these models by using the notifications of the
following day.
We test the data-driven models with three prediction algo-
rithms: Naive Bayes, AdaBoost, and Random Forest. We
use user-defined rules as the baseline to evaluate the predic-
tion results of other predictors. As shown in Figure 8, Ad-
aBoost and Random Forest are the best performers. In the
initial days, AdaBoost starts makes better predictions as com-
pared to Random Forest. However, the prediction accuracy of
AdaBoost stabilizes after seven days. On the other hand, the
Naive Bayes algorithm initially shows a prediction accuracy
performance comparable to AdaBoost and Random Forest,
but its rate of increase in accuracy slowly declines. Overall,
all the predictors outperform the user-defined rule mechanism
after 2 days. It is worth noting that the best two predictors
show the best performance after 9 days of training.
According to our measurements, the users in our study re-
ceive around 100 notifications each day on average. These
notifications arrive at different times of the day without any
knowledge about recipients’ willingness to get interrupted.
Therefore, such notifications have a potential to convert
the smartphone from an information-awareness device to an
information-overloading one. At the same time, our results
show that the response to a notification can be predicted. The
user’s predicted response can be used to ensure the delivery
of notifications at opportune moments.
To predict the user response to a notification we need to build
a user’s behavioral model and train it with the notifications of
various categories that arrive in different contexts. It is pos-
sible to capture the user’s context via a smartphone’s embed-
ded sensors. On the other hand, to categorize notifications we
need the knowledge about the information contained in them.
Some notifications can be classified by using the knowledge
about the category of applications which triggered them. For
example, an application of news category is very likely to
trigger notifications containing news related information.
Our results show that around 70% of the notifications that a
user receives belong to email and chat categories. Thus, a fur-
ther subcategorization of these two categories is needed. As
proposed in this study, we can use the social circles of users
to sub-categorize email and chat notifications. For example,
a chat notification can be sub-categorized as "social chat" if
the sender of the notification belongs to the friend circle de-
fined by the user. Communication applications (e.g., email
and chat) allow the users to map their social ties in the social
circles defined by them. One possibility is that these circles
can be used by an application to categorize email and chat
notifications. However, the users do not create social circles
on every communication applications and also the reverse is
true that not all communication applications facilitate users to
create social circles. This raises an interesting question about
how to maintain the knowledge about users’ social circle that
can be used to sub-categorize the chat and email notifications.
In a recent study [18], authors argue that the operating system
of a mobile device should be responsible for managing and
delivering notifications at the opportune moments. Inspired
by the authors argument, we suggest a solution to the prob-
lem, posed above, to maintain the knowledge about a users’
social circle. Since the operating system has access to all
the information of every application, there should be a sys-
tem service (such as Google Play Service for Android OS)
that can categorize all notifications with respect to the appli-
cation which triggered it and an aggregated social circle of
the user generated by merging social circles from different
applications (especially from the social networking and cal-
endar applications). Such a service can monitor the user’s
response for all notification categories in different contexts.
Thus, there will be more data available to build a richer model
of the user’s behavior as compared to the models created by
the applications themselves. Also, we believe that this ser-
vice can provide an efficient solution because we only need
to train a single but rich behavioral model of a user.
In this work we consider two cases of user’s response to a
notification – accept (i.e., when a user clicks on the notifica-
tion to read the information contained in it) and decline (i.e.,
when a user ignores or does not answer the notification up to
a certain time delay). However, it is possible that some no-
tifications were misclassified as declined because they might
be actually attended by the users on another device or they
might be read and dismissed by the users because they do not
require further actions. Thus, the prediction model is trained
by means of incorrect data.
We also identify a series of aspects that deserve further in-
vestigation, probably also by means of experience sampling
techniques. One issue is related to multiple notifications from
the same applications (usually referred to as “stacked” noti-
fications). How does a user react when the notifications are
stacked by an application? Does a user click/ignore it be-
cause all notifications are irrelevant or because a notification
(perhaps the latest one) from the stack is important/not impor-
tant? Another important aspect is related to the influence of
the user’s co-location with other people when a notification is
received. For example, a certain user sitting in a coffee shop
alone might be willing to accept a notification. But, when the
same user is sitting with colleagues and discussing a project,
she might not accept any notification.
Sahami et al. [28] ran a large-scale study to understand how
users perceive mobile notifications. Their results show that
the users deal with many notifications each day, and most of
the notifications are viewed within a few minutes of arrival.
Additionally, by collecting the subjective feedback from the
mobile users, the authors show that users assign different im-
portance to notifications triggered by application from dif-
ferent categories. In a recent study, Pielot et al. [25] show
that the personal communication notifications are responded
to quickly because of the social pressure and the exchange of
time critical information by the communication applications.
Although, these notifications make the users feel connected
with their social links, the increasing number of such notifica-
tions also becomes a source of negative emotions and stress.
These results demonstrate that the users are not always in-
terested in the information pushed by the proactive services.
Thus, it becomes necessary for such services to push only the
right information at the right time. At the same time, as Iqbal
et al. [16] suggest, users are willing to tolerate some disrup-
tion in return for receiving notifications that contain valuable
Most of the work on mobile interruptibility management fo-
cuses on the user’s context for inferring opportune moments
to interrupt [10, 15, 16]. Ho and Intille [15] explore the de-
livery of notifications at the transition between physical ac-
tivities. Their results suggest that notifications might be con-
sidered more positively when delivered between two physical
activities, such as sitting and walking. Similarly, Fischer et
al. [10] investigate whether the transitions between the user’s
interaction with the mobile phone are opportune to deliver no-
tifications. They conducted an experience sampling study in
which the notifications asked users to provide feedback about
their context (for instance, taking a photo of the surround-
ings) during different phases of their interaction with mobile
phones. They found that the participants react faster to noti-
fications when they are delivered immediately at the end of
a task such as after finishing a phone call or reading a text
message. In a recent study, Pielot et al. [26] identified that
the shared indicators of availability (such as the last time the
user has been online) are weak predictors of users’ respon-
siveness for notifications. The authors show that features,
such as the last notification response, phone’s ringer mode
and user’s proximity to the screen, are good predictors of a
notification’s response time, and can predict whether a noti-
fication will be seen by the recipient within a few minutes
with 70.6% accuracy. These studies remain limited to detect
generic moments to interrupt users by notifications and fail to
provide a complete picture of user’s willingness to accept a
notification. This is due to the fact that they ignore the role
of content for modeling interruptibility. In this study, instead,
we will discuss the design of a content-driven mechanism for
predicting an opportune moment to deliver a notification.
A handful of previous studies have incorporated aspects of
content for studying interruptibility [12, 29, 11]. Grandhi and
Jones [12] propose a theoretical framework for interruptibil-
ity management that takes into account who the interruption
is from and what it is about, in a desktop-based setting. The
authors do not provide evidence to show how the framework
can work in a mobile environment. Speier et al. [29] use the
relevance of the notification content with the ongoing desktop
activity to predict the cost of interruption caused by the de-
livered information. Such an approach can work in desktop
environments where the users’ context is not very dynamic.
The pervasive nature of mobile phones brings in various ad-
ditional contextual features, in particular the fact that the de-
vices are used, essentially, everywhere and potentially at any
time of the day. Thus, it becomes important to consider the
relevance of content within the context.
On the other hand, Fischer et al. [11] investigate the effects
of content and the time of delivery of a mobile notification
on users’ response. The authors show that a notification’s
response is influenced by the user’s general interest in the no-
tification content, entertainment value perceived in it and ac-
tions required by the notification, but not the time of delivery.
However, first, the authors do not fully justify the ecological
validity of their approach because the notifications delivered
to the users were not real world notifications but were gener-
ated by their own system; second, they consider the general
interest of the users and entertainment value in the informa-
tion, but we argue that the value of such factors are perceived
differently by the users in different contexts. Our intelligent
notification mechanism not only overcomes such limitations
by considering user’s behavior about "what (type of informa-
tion)" and "where (user’s context)" to receive mobile notifica-
tions, but also uses the social circles to exploit the recipient’s
relationship with the sender.
To the best of our knowledge there is no mobile interruption
study that considers both of these two factors together to pre-
dict opportune moments for delivering mobile notifications.
Moreover, this study uses in-the-wild notifications for the first
time to model interruptibility; indeed, existing work is based
on synthetic notifications or desktop-based experiments.
Mobile notifications provide an effortless way to enable users
to be aware of newly available information in quasi real-
time. However, notifications arrive at inappropriate moments
or carry irrelevant content. In this paper we have presented an
analysis of the impact of content on the acceptance of mobile
notifications. The results of the analysis have been used to
develop a novel machine learning approach that predicts the
acceptance of a notification by using its content and the con-
text in which it is delivered. Such an approach can be used by
an interruptibility management system to ensure that the right
information is delivered at the right time.
We have collected notifications “in-the-wild" and classified
them according to the information contained in them. Our re-
sults have shown that a user’s activity can impact the time de-
lay in the response to a notification. We have evaluated the av-
erage percentage of the notifications that are accepted in a day
for each notification category. Our results have shown that the
chat notifications, where the sender is a family member or a
relative of the user, have the highest acceptance rate. Overall,
the acceptance value of notifications vary for each category.
By using the collected real-world notifications we have de-
signed, developed and tested a series of predictors based on
state-of-the-art machine learning. We have shown that the ac-
ceptance of a notification within 10 minutes from its arrival
time can be predicted with an average sensitivity of 70% and
a specificity of 80%. For some users the sensitivity can go up
to 89%. Our approach outperforms the user-defined rules for
delivering notifications on their mobile phones. Finally, we
have discussed the implementation of an online predictor in
order to understand the required training period for successful
We consider this work an initial step towards the implemen-
tation an effective and efficient component for notification
management. We believe that the accuracy of the prediction
model will increase by considering fine-grained categories
that can be obtained by classifying the notification content
using natural language processing techniques. Another or-
thogonal issue that will play a fundamental role in the de-
velopment of these technology is privacy: indeed, the imple-
mentation of the proposed algorithms involve the analysis of
user-generated content and of the social relationships of the
users. Our goal is to explore ways for performing advanced
processing on the phones in order to minimize the sharing of
personal information with third-party entities.
This work was supported through the EPSRC grants “UB-
have: ubiquitous and social computing for positive behaviour
change" (EP/I032673/1) and “Trajectories of Depression:
Investigating the Correlation between Human Mobility Pat-
terns and Mental Health Problems by means of Smartphones"
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... For example, the quality of the notification content in terms of entertainment value, relevance, user interest, and actionability has been linked to receptivity (Fischer et al., 2010). Evidence also suggests that people are more responsive to certain categories of notifications, such as family chat and work email notifications over those relating to system, tools, and media and music (Mehrotra, Musolesi, Hendley, & Pejovic, 2015), and particular senders, for example partners and immediate family members compared to extended family members or service providers (Mehrotra, Pejovic, Vermeulen, Hendley, & Musolesi, 2016). Certain activities and tasks, such as when idle (Choi et al., 2019;Mehrotra, Pejovic, Vermeulen, Hendley, & Musolesi, 2016) or traveling in a vehicle (Mehrotra, Musolesi, Hendley, & Pejovic, 2015), are linked to greater receptivity while others, such as communicating (Mehrotra, Pejovic, Vermeulen, Hendley, & Musolesi, 2016), studying, or exercising (Yuan, Gao, & Lindqvist, 2017) are linked to lesser receptivity. ...
... Evidence also suggests that people are more responsive to certain categories of notifications, such as family chat and work email notifications over those relating to system, tools, and media and music (Mehrotra, Musolesi, Hendley, & Pejovic, 2015), and particular senders, for example partners and immediate family members compared to extended family members or service providers (Mehrotra, Pejovic, Vermeulen, Hendley, & Musolesi, 2016). Certain activities and tasks, such as when idle (Choi et al., 2019;Mehrotra, Pejovic, Vermeulen, Hendley, & Musolesi, 2016) or traveling in a vehicle (Mehrotra, Musolesi, Hendley, & Pejovic, 2015), are linked to greater receptivity while others, such as communicating (Mehrotra, Pejovic, Vermeulen, Hendley, & Musolesi, 2016), studying, or exercising (Yuan, Gao, & Lindqvist, 2017) are linked to lesser receptivity. Research has also shown a negative association between perceived task complexity (complex vs. less complex) and receptivity (Mehrotra, Pejovic, Vermeulen, Hendley, & Musolesi, 2016). ...
... 6 Sender Mehrotra, Musolesi, Hendley, & Pejovic, 2015Yuan et al., 2017 Individuals are more receptive to notifications sent by significant others (e.g., family members, colleagues at work). ...
Intervention authors can likely increase the effectiveness of mobile health interventions (MHIs) by determining conditions under which individuals are able to receive, process, and use support. In this chapter, we will therefore first introduce and motivate the relevance of receptivity to MHIs. Second, we will describe the anatomy of an “ideal” MHI before key processes involved in the detection and prediction of receptivity to MHIs are discussed. Thereafter, we will review research on receptivity and summarize factors that may carry relevant signals for determining receptive states and thus, offer guidance for the design of receptivity-capable MHIs. We will conclude with challenges intervention authors and engineers face and offer opportunities for future work.
... However, neither the user's location nor surroundings have yet proven to be important factors in improving or reducing interruptibility. Mehrotra et al. (2015) did not find significant improvement in the response times to push notifications based on users' location. Another approach, using noise sensors in mobile phones (Poppinga, Heuten & Boll, 2014) was found to be an insignificant factor for explaining users' response. ...
Mobile apps market is a growing market and the main technological enabler of apps are push notifications (PN). Today, users are currently receiving a daily average of 63 PN. After an introduction that highlights the relevance of PN, this chapter covers the background of its topic –pop-up messages that emerge on the smartphone screen- and its characterization: (1) proactive communication with the user; (2) explicitly authorized through an opt-in request; (3) wide range of content, private and social, sent by social networks, commercial companies, or news publishers from apps or web site; (4) targeted according to the users’ interests, previous behaviors, or time of day; (6) always prompting the user to click on the PN that will land on the sender’s app / web site. There is a steep competition for the user's attention to click through the PN message. Thus the chapter moves through to discuss the factors that influence the choice of whether to open or ignore a PN: (1) Timing in the delivery, disruption, and systems for managing PN in a non-disruptive way. (2) Top-down factors in PN usage, such as user profile, user reaction times, and user interest in the content (3) Bottom-up factors, such as message textual and visual features as an antecedent of click-through rate. Before concluding, the chapter suggests future directions for researchers and practitioners: how to increase opt-in rates, user experience of PN, reasons to opt-out … The chapter ends with a conclusion and a list of references.
... Bayes [22,57], perceptron [75,76], support vector machines [3], or random forests [58,64] are used and models are learned offline [3] and online [75]. Due to the problem setting, these approaches require users' input to be highly predictive of the most appropriate adaptation. ...
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The goal of Adaptive UIs is to automatically change an interface so that the UI better supports users in their tasks. A core challenge is to infer user intent from user input and chose adaptations accordingly. Designing effective online UI adaptations is challenging because it relies on tediously hand-crafted rules or carefully collected, high-quality user data. To overcome these challenges, we formulate UI adaptation as a multi-agent reinforcement learning problem. In our formulation, a user agent learns to interact with a UI to complete a task. Simultaneously, an interface agent learns UI adaptations to maximize the user agent's performance. The interface agent is agnostic to the goal. It learns the task structure from the behavior of the user agent and based on that can support the user agent in completing its task. We show that our approach leads to a significant reduction in necessary number of actions on a photo editing task in silico. Furthermore, our user studies demonstrate the generalization capabilities of our interface agent from a simulated user agent to real users.
... IBI rate [288,262]. Mehrotra et al. reported that the users' perception of the interruption depends on the sender of a notification, and chat notifications from family members have the highest acceptance rates. We considered both the length of the notification and the sender of the message. ...
Catching the attention of users, via their smartphone, is most often achieved through push notifications. Such an approach is already in place within applications such as Facebook, Google, Instagram, TikTok, and Twitter. Emails and messaging apps are also used to send notifications, which can assist users who may otherwise miss important events. As a result of these multiple services the user may be overwhelmed with notifications and frequently interrupted during key task. To address this concern, a mobile app has been developed for collecting different phone events and sensors data “in-the-wild”. This data which is then used as the basis for behavioural modeling to profile a user and subsequently detect the best time to send a notification. Within the mobile app, a service is running continuously in the background, collecting sensor data (such as accelerometer and gyroscope data), notification data such as notification title, and user response data relating to engagement with notifications and phone events such as foreground app name, battery percentage etc. Additionally, the app collects user cognitive state data through self-reporting. This paper analyse a dataset contributed by five users. In total, 2766 notifications were received over period of up to 10 days. 78% percent of the time, users ignored or remove notifications based on the data analysis. It is therefore a serious issue in the realm of ubiquitous computing that there is a constant bombardment of push notifications.
Push-notifications, by design, attempt to grab the attention of subscribers and impart new or valuable information in a particular context. These nudges are commonly initiated by marketing teams and subsequent delivery interruptions tend to conflict with subscriber priorities and activities. In this work, we present a definition of urgency applied to notifications. We describe its value in an ontology for push-notification annotation and also evaluate a variety of classification models tasked with distinguishing urgency levels in notification text. The best model achieved an F1-score of 0.89. The proposed models have the potential to benefit subscribers by helping them better prioritize incoming notifications and also aid marketers in creating time-relevant campaigns.
A significant proportion of smartphone notifications are indicative of human behaviour (e.g. delivery updates for purchased items, physical activity summaries, and notification of updates to subscribed content). However, present attempts to understand human behaviour from smartphone traces typically focus on sensors such as location, accelerometer and proximity, overlooking the potential for notifications as a valuable data source. In this paper, we propose a general framework that provides end-to-end processing of notifications to understand behavioural aspects. We realise the framework with an implementation that tackles the specific use case of establishing prior buying behaviour from associated notifications. To evaluate the framework and implementation, we conduct a longitudinal user study in which we collect more than 250, 000 notifications, from twelve users, over an average of three months. We apply knowledge-based and machine learning techniques to those notifications to assess the tasks of the proposed framework. The results show a substantial difference in the performance between the methods used to extract behavioural features from the collected notifications.
Modern dairy farms are increasingly adopting technologies to monitor animal health and welfare and send notifications to farmers when issues arise. These precision livestock farming (PLF) technologies promise increased animal health and farm productivity. Yet, few studies exist on the effects of these technologies on those who use them. Studies from Europe show the 24/7 nature of potential PLF notifications can make farmers feel always “on call”, increasing their overall stress levels. An initial online survey of 18 Canadian dairy farmers was conducted to explore their experiences with PLF notifications. Reported benefits of PLF technologies include improved animal health and dairy products, labor benefits, and ease of data collection. The study also uncovered weaknesses of PLF notifications, including information uncertainty and overload, false alerts, inappropriate timing and communication mediums. Design recommendations are presented to improve PLF notification mechanisms.KeywordsPrecision livestock farming (PLF) technologyNotification mechanismsImpact of PLF on dairy farmersFarmers’ mental workload
Smart glasses are increasingly commercialized and may replace or at least complement smartphones someday. Common smartphone features, such as notifications, should then also be available for smart glasses. However, notifications are of disruptive character given that even unimportant notifications frequently interrupt users performing a primary task. This often leads to distractions and performance degradation. Thus, we propose a concept for displaying notifications in the peripheral field of view of smart glasses and with different visualizations depending on the priority of the notification. We developed three icon-based notifications representing increasing priority: a transparent green icon continuously becoming more opaque (low priority), a yellow icon moving up and down (medium priority), and a red and yellow flashing icon (high priority). To evaluate the concept, we conducted a study with 24 participants who performed a primary task and should react to notifications at the same time using the Nreal Light smart glasses. The results showed that reaction times for the low-priority notification were significantly higher and it was ranked as the least distracting. The medium- and high-priority notifications did not show a clear difference in noticeability, distraction, or workload. We discuss implications of our results for the perception and visualization of notifications in the peripheral field of view of smart glasses and, more generally, for augmented reality applications.
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Notifications on mobile phones alert users about new messages, emails, social network updates, and other events. However, little is understood about the nature and effect of such notifications on the daily lives of mobile users. We report from a one-week, in-situ study involving 15 mobile phones users, where we collected real-world notifications through a smartphone logging application alongside subjective perceptions of those notifications through an online diary. We found that our participants had to deal with 63.5 notifications on average per day, mostly from messengers and email. Whether the phone is in silent mode or not, notifications were typically viewed within minutes. Social pressure in personal communication was amongst the main reasons given. While an increasing number of notifications was associated with an increase in negative emotions, receiving more messages and social network updates also made our participants feel more connected with others. Our findings imply that avoiding interruptions from notifications may be viable for professional communication, while in personal communication, approaches should focus on managing expectations.
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Conference Paper
Smartphone sensing enables inference of physical context, while online social networks (OSNs) allow mobile applications to harness users’ interpersonal relationships. However, OSNs and smartphone sensing remain disconnected, since obstacles, including the synchronization of mobile sensing and OSN monitoring, inefficiency of smartphone sensors, and privacy concerns, stand in the way of merging the information from these two sources. In this paper we present the design, implementation and evaluation of SenSocial, a middleware that automates the process of obtaining and joining OSN and physical context data streams for the development of ubiquitous computing applications. SenSocial enables instantiation, management and aggregation of context streams from multiple remote devices. Through micro-benchmarks we show that SenSocial successfully and efficiently captures OSN and mobile sensed data streams. We developed two prototype applications in order to evaluate our middleware and we demonstrate that SenSocial significantly reduces the amount of programming effort needed for building social sensing applications.
The mobile phone represents a unique platform for interactive applications that can harness the opportunity of an immediate contact with a user in order to increase the impact of the delivered information. However, this accessibility does not necessarily translate to reachability, as recipients might refuse an initiated contact or disfavor a message that comes in an inappropriate moment. In this paper we seek to answer whether, and how, suitable moments for interruption can be identified and utilized in a mobile system. We gather and analyze a real-world smartphone data trace and show that users' broader context, including their activity, location, time of day, emotions and engagement, determine different aspects of interruptibility. We then design and implement InterruptMe, an interruption management library for Android smartphones. An extensive experiment shows that, compared to a context-unaware approach, interruptions elicited through our library result in increased user satisfaction and shorter response times.
From wearable displays to smart watches to in-vehicle info- tainment systems, mobile computers are increasingly inte- grated with our day-to-day activities. Interactions are com- monly driven by applications that run in the background and notify users when their attention is needed. In this paper, we argue that existing mobile operating systems should manage user attention as a resource. In contrast to permission-based models that either allow applications to interrupt the user continuously or deny all access, the OS should instead pre- dict the importance and complexity of new interactions and compare the demand for attention to the attention available after accounting for the user's current activities. This will allow the OS to initiate appropriate interactions at the right time using the right modality. We describe one design for such a system, and we outline key challenges that must be met to realize this vision.
Reliable smartphone app prediction can strongly benefit both users and phone system performance alike. However, real-world smartphone app usage behavior is a complex phenomena driven by a number of competing factors. In this pa- per, we develop an app usage prediction model that leverages three key everyday factors that affect app usage decisions -- (1) intrinsic user app preferences and user historical patterns; (2) user activities and the environment as observed through sensor-based contextual signals; and, (3) the shared aggregate patterns of app behavior that appear in various user communities. While rapid progress has been made recently in smartphone app prediction, existing prediction models tend to focus on only one of these factors. We evaluate a multi-faceted approach to prediction using (1) a 3-week 35-user field trial, along with (2) analysis of app usage logs of 4,606 smartphone users worldwide. We find our app usage model can not only produce more robust app predictions than conventional techniques, but it can also enable significant smartphone system optimizations.
Conference Paper
The ubiquity of sensor-rich and computationally powerful smartphones makes them an ideal platform for conducting social and behavioural research. However, building sensor data collection tools remains arduous and challenging: it requires an understanding of the varying sensor programming interfaces as well as the research issues related to building sensor-sampling systems. To alleviate this problem and facilitate the development of social sensing and data collection applications, we are developing a set of open-source smartphone libraries to collect, store and transfer, and query sensor data. Furthermore, we have also developed a library that can trigger notifications based on time or sensor events to assist experience sampling methods. This paper presents these libraries' architecture, initial feedback from developers using it, and a sensing application that we built using them to study daily affect.