An investigation of the predictability of the Brazilian three-modal hand-based behavioural biometric: a feature selection and feature-fusion approach

Abstract: New security systems, methods or techniques need to have their performance evaluated in conditions that closely resemble a real-life situation. The effectiveness with which individual identity can be predicted in different scenarios can benefit from seeking a broad base of identity evidence. Many approaches to the implementation of biometric-based identification systems are possible, and different configurations are likely to generate significantly different operational characteristics. The choice of implementational structure is, therefore, very dependent on the performance criteria, which is most important in any particular task scenario. The issue of improving performance can be addressed in many ways, but system configurations based on integrating different information sources are widely adopted in order to achieve this. Thus, understanding how each data information can influence performance is very important. The use of similar modalities may imply that we can use the same features. However, there is no indication that very similar (such as keyboard and touch keystroke dynamics, for example) basic biometrics will perform well using the same set of features. In this paper, we will evaluate the merits of using a three-modal hand-based biometric database for user prediction focusing on feature selection as the main investigation point. To the best of our knowledge, this is the first thought-out analysis of a database with three modalities that were collected from the same users, containing keyboard keystroke, touch keystroke and handwritten signature. First, we will investigate how the keystroke modalities perform, and then, we will add the signature in order to understand if there is any improvement in the results. We have used a wide range of techniques for feature selection that includes filters and wrappers (genetic algorithms), and we have validated our findings using a clustering technique

Anforderungsanalyse für kollaborative Brainstorming-Anwendungen an einer interaktiven Displaywand

Brainstorming ist eine weit verbreitete Technik zur Ideengenerierung, die dazu dient, in kurzer Zeit möglichst viele verschiedene Ideen zu sammeln. Diese Technik wird zur Problemlösung, Entscheidungsfindung oder zur Erstellung neuer Konzepte verwendet. Entstandene Ideen können in Form eines Affinitätsdiagramms auf separaten Notizzetteln dargestellt werden. Für die kollaborative Erstellung eines Affinitätsdiagramms eignen sich wegen der Größe und der Fähigkeit der direkten Manipulation interaktive Displaywände. So können die Nutzer in der ersten Phase des Brainstormings individuell und simultan Ideen sammeln, bevor diese in der zweiten Phase gut übersichtlich auf dem großen Display sortiert und bewertet werden. In dieser Arbeit geht es um die Anforderungen, die eine Brainstorming-Anwendung besitzen muss, damit an einer interaktiven Displaywand ein Affinitätsdiagramm erstellt werden kann. Dabei liegt der Fokus zunächst auf grundlegenden Funktionalitäten, die basierend auf der Analyse von kommerziellen Brainstorming-Anwendungen ausgewählt werden. Aus dieser Analyse und weiterer verwandter Arbeiten zu den Themen Brainstorming und Kollaboration an interaktiven Displaywänden werden Konzepte für eine Brainstorming-Anwendung vorgestellt. Ausgewählte Konzepte wurden daraufhin prototypisch implementiert. Diese werden basierend auf Nutzer-Tests untersucht und ausgewertet, um daraus Schlüsse für die weitere Herangehensweise zu ziehen.:1 Einleitung 1 2 Verwandte Arbeiten 3 2.1 Interaktive Displaywände 3 2.1.1 Interaktion an Displaywänden 3 2.1.2 Kollaboration 6 2.2 Brainstorming 8 2.2.1 Analoges Brainstorming 8 2.2.2 Digitales Brainstorming 10 2.3 Designempfehlungen für eine Brainstorming-Anwendung an einer interaktiven Displaywand 15 3 Konzepte zur kollaborativen Erstellung eines Affinitätsdiagramms an interaktiven Displaywänden 19 3.1 Aufteilung der Funktionalitäten in verschiedene Menüs 20 3.1.1 Globales Menü 20 3.1.2 Lokales Menü 21 3.1.3 Kontextmenü 23 3.2 Erstellen, Bearbeiten und Löschen von Notizen 23 3.2.1 Erstellen von Notizen 24 3.2.2 Öffnen des Kontextmenüs 25 3.2.3 Bearbeiten und Löschen einer Notiz und dessen Inhalt 26 3.3 Sortieren und Gruppieren der Notizen 27 3.4 Kollaborative Funktionalitäten 28 3.5 Fingermenü als Ergänzung der bestehenden Menüs 33 4 Prototypische Implementierung 37 4.1 Technische Rahmenbedingungen 37 4.2 Implementierungsgrundlage 38 4.3 Umgesetzte Konzepte 39 4.4 Resultate 42 5 Auswertung und Ausblick 45 5.1 Auswertung der vorgestellten Konzepte und des implementierten Prototypen 45 5.2 Ausblick 49 5.2.1 Evaluation mit gut funktionierendem Prototypen 49 5.2.2 Erweiterung bestehender Funktionalitäten 49 5.2.3 Weitere Möglichkeiten der Interaktion an Displaywänden 51 5.3 Zusammenfassung 53 A Anhang 55 Literatur 57Brainstorming is a widely used technique aiming to collect as many different ideas as possible in a brief amount of time. This technique is used for problem solving, decision making or the creation of new concepts. Emerged ideas can be represented in the form of an affinity diagram on sticky notes. For the collaborative creation of an affinity diagram, interactive display walls are a suitable medium because of their size and the possibility of direct manipulation. In the first phase of brainstorming, users can collect ideas individually and simultaneously. These ideas can be sorted and evaluated on the large display in a clearly arranged manner in the second phase. This work deals with requirements, that a brainstorming application has to offer to create an affinity diagram on an interactive display wall. Initially, the focus will be on basic functionality based on the analysis of commercial brainstorming tools. From this analysis and other related works on the topic of brainstorming and collaboration on interactive display walls, concepts for a brainstorming application are presented. Selected concepts were then prototypically implemented. Based on user tests, the concepts will be examined and evaluated.:1 Einleitung 1 2 Verwandte Arbeiten 3 2.1 Interaktive Displaywände 3 2.1.1 Interaktion an Displaywänden 3 2.1.2 Kollaboration 6 2.2 Brainstorming 8 2.2.1 Analoges Brainstorming 8 2.2.2 Digitales Brainstorming 10 2.3 Designempfehlungen für eine Brainstorming-Anwendung an einer interaktiven Displaywand 15 3 Konzepte zur kollaborativen Erstellung eines Affinitätsdiagramms an interaktiven Displaywänden 19 3.1 Aufteilung der Funktionalitäten in verschiedene Menüs 20 3.1.1 Globales Menü 20 3.1.2 Lokales Menü 21 3.1.3 Kontextmenü 23 3.2 Erstellen, Bearbeiten und Löschen von Notizen 23 3.2.1 Erstellen von Notizen 24 3.2.2 Öffnen des Kontextmenüs 25 3.2.3 Bearbeiten und Löschen einer Notiz und dessen Inhalt 26 3.3 Sortieren und Gruppieren der Notizen 27 3.4 Kollaborative Funktionalitäten 28 3.5 Fingermenü als Ergänzung der bestehenden Menüs 33 4 Prototypische Implementierung 37 4.1 Technische Rahmenbedingungen 37 4.2 Implementierungsgrundlage 38 4.3 Umgesetzte Konzepte 39 4.4 Resultate 42 5 Auswertung und Ausblick 45 5.1 Auswertung der vorgestellten Konzepte und des implementierten Prototypen 45 5.2 Ausblick 49 5.2.1 Evaluation mit gut funktionierendem Prototypen 49 5.2.2 Erweiterung bestehender Funktionalitäten 49 5.2.3 Weitere Möglichkeiten der Interaktion an Displaywänden 51 5.3 Zusammenfassung 53 A Anhang 55 Literatur 5

{GravitySpot}: {G}uiding Users in Front of Public Displays Using On-Screen Visual Cues

Figure 1. GravitySpot guides users towards designated positions in front of a display. We modify UI properties, such as brightness or resolution of images, depending on the user position. Thus we make passersby anticipate the spot where they can optimally perceive the content. In a sample application deployed in the wild, a trivia game is initiated as a user approaches the display (left). The answer is then provided as image which we modify based on user position (here pixelation, middle). As users move towards the sweet spot, the effect gets smaller until they can optimally perceive the image (right). Users tend to position themselves in front of interactive pub-lic displays in such a way as to best perceive its content. Cur-rently, this sweet spot is implicitly defined by display proper-ties, content, the input modality, as well as space constraints in front of the display. We present GravitySpot – an approach that makes sweet spots flexible by actively guiding users to ar-bitrary target positions in front of displays using visual cues. Such guidance is beneficial, for example, if a particular input technology only works at a specific distance or if users should be guided towards a non-crowded area of a large display. In two controlled lab studies (n=29) we evaluate different visual cues based on color, shape, and motion, as well as position-to-cue mapping functions. We show that both the visual cues and mapping functions allow for fine-grained control over po-sitioning speed and accuracy. Findings are complemented by observations from a 3-month real-world deployment

My scrawl hides it all: Protecting text messages against shoulder surfing with handwritten fonts

We present a novel concept for protecting text messages (e.g. notifications) on mobile devices from shoulder surfing. We propose to display the text in the user's handwriting, assuming that people can read their own handwriting easier and faster than strangers. Our approach was evaluated in a proof-of-concept user study that revealed significant differences in reading time: Participants were indeed slower when reading the unfamiliar handwriting of the other participants compared to their own, and they tended to make more errors. Even though this effect was not present for all participants, we argue that our results may provide the basis for protection mechanisms applicable in real-world scenarios

SnapApp: Reducing authentication overhead with a time-constrained fast unlock option

We present SnapApp, a novel unlock concept for mobile devices that reduces authentication overhead with a time-constrained quick-access option. SnapApp provides two unlock methods at once: While PIN entry enables full access to the device, users can also bypass authentication with a short sliding gesture ("Snap"). This grants access for a limited amount of time (e.g. 30 seconds). The device then automatically locks itself upon expiration. Our concept further explores limiting the possible number of Snaps in a row, and configuring blacklists for app use during short access (e.g. to exclude banking apps). We discuss opportunities and challenges of this concept based on a 30-day field study with 18 participants, including data logging and experience sampling methods. Snaps significantly reduced unlock times, and our app was perceived to offer a good tradeoff. Conceptual challenges include, for example, supporting users in configuring their blacklists