| On user involvement in production of images used in visual authentication | | BIBAK | Full-Text | 1-15 | |
| Karen Renaud | |||
| Recognition-based visual authentication schemes use a variety of different
kinds of images. These mechanisms have now matured sufficiently that we should
start considering tailoring and fine-tuning them -- looking at ways to make
them more efficient. Since these mechanisms use images, the obvious starting
point in this tailoring process is to consider the image type or genre being
used by the mechanism.
Images have a number of properties which are bound to influence the efficacy of the visual authentication mechanism. In this paper the notion of essential and tuning image properties is proposed. The former are those that an image must exhibit or possess in order to be used in visual authentication at all -- failure to meet these metrics should disqualify the image from use. Tuning properties, on the other hand, are properties that will improve the efficiency of the mechanism. The tuning property which is the focus of this paper is the user's involvement in the production of his/her secret images. A longitudinal study was carried out with a visual authentication system in order to determine the effectivity of images with three levels of user involvement, using randomly issued images from an archive, a set of hand-drawn images called doodles, and user-provided photos. The hand-drawn doodles performed better than both system-issued images and personal photos. Furthermore, whereas doodles demonstrate viability, personal photos have many insuperable problems which make them unsuitable for use in a security setting. Keywords: Security; Visual authentication; Image type | |||
| End-user strategy programming | | BIBAK | Full-Text | 16-29 | |
| Christoph Neumann; Ronald A. Metoyer; Margaret Burnett | |||
| Rule-based programming systems can be fragile because they force the user to
account for all logical alternatives. If an unconsidered case does arise during
execution, program behavior falls through the cracks into unspecified behavior.
We investigate rule-based, end-user strategy programming by introducing our
Interactive Football Playbook -- a domain specific, end-user programming
environment to allow American football coaches to create animated football
scenarios by associating strategy information with virtual football players. We
address the problem of rule explosion through "rule bending" to support a
minimalist, scaffolding-driven programming environment. Additionally, we
introduce visual language representations for logical and sequential "and" to
mitigate end-user confusion with the semantic meaning of these "and"
constructs. Keywords: End-user programming; Natural programming; Visual programming; Computer animation; American football | |||
| The expressiveness of spider diagrams augmented with constants | | BIBAK | Full-Text | 30-49 | |
| Gem Stapleton; John Taylor; Simon Thompson; John Howse | |||
| Spider diagrams are a visual language for expressing logical statements or
constraints. Several sound and complete spider diagram systems have been
developed and it has been shown that they are equivalent in expressive power to
monadic first order logic with equality. However, these sound and complete
spider diagram systems do not contain syntactic elements analogous to constants
in first order predicate logic. We extend the spider diagram language to
include constant spiders which represent specific individuals. Formal semantics
are given for the extended diagram language. We prove that this extended system
is equivalent in expressive power to the language of spider diagrams without
constants and, hence, equivalent to monadic first order logic with equality. Keywords: Diagrammatic logic; Visual formalism; Formal methods | |||
| Cognitive support through visualization and focus specification for understanding large class libraries | | BIBAK | Full-Text | 50-59 | |
| Jauhar Ali | |||
| Effective object-oriented (OO) programming requires understanding class
libraries. This paper presents our approach to design and build a cognitive
tool that supports a programmer to understand OO class libraries. The MUDRIK
system provides (1) three-dimensional visualization mechanisms for representing
class structures and relationships from a variety of views and (2) flexible
focus specification mechanisms that allow users to adapt a space of components
to be displayed according to the task at hand. Interactive views of MUDRIK
enable programmers to examine components' detail while maintaining a global
representation of the rest of the library. The paper describes why
understanding class library is critical in OO programming, presents a cognitive
framework of our approach and design rationale behind the system design, and
provides a detailed description of the system followed by a discussion on our
approach. Keywords: Class library understanding; Software visualization; 3D visualization; Java programming; Cognitive tools; Reuse; Human-computer interaction | |||
| Immersive authoring of Tangible Augmented Reality content: A user study | | BIBAK | Full-Text | 61-79 | |
| Gun A. Lee; Gerard J. Kim | |||
| Immersive authoring refers to the style of programming or developing content
from within the target-executable environment. Immersive authoring is important
for fields such as augmented reality (AR) in which interaction usability and
user perception of the target content must be checked first hand, in situ. In
addition, the interaction efficiency and usability of the authoring tools
itself is equally important for ease of authoring. In this paper, we propose
design principles and describe an implementation of an immersive authoring
system for AR. More importantly, we present a formal user study demonstrating
its benefits and weaknesses. In particular, our results demonstrate that,
compared to using the traditional 2D desktop development method, immersive
authoring gained significant efficiency in specifying spatial arrangements and
behavior tasks, a major component of AR content authoring. However, it was not
so successful for abstract tasks such as logical programming. Based on this
result, we suggest that a comprehensive AR authoring tool should include such
immersive authoring functionality to help, particularly non-technical media
artists, create effective contents based on the characteristics of the
underlying media and interaction style. Keywords: Immersive authoring; Augmented reality; Tangible interface; User study; Interaction design | |||
| Personal verification based on extraction and characterisation of retinal feature points | | BIBAK | Full-Text | 80-90 | |
| Marcos Ortega; M. G. Penedo; J. Rouco; N. Barreira; M. J. Carreira | |||
| This paper describes a methodology of verification of individuals based on a
retinal biometric pattern. The pattern consists in feature points of the
retinal vessel tree, namely bifurcations and crossovers. These landmarks are
detected and characterised adding semantic information to the biometric
pattern. The typical authentication process of a person once extracted the
biometric pattern includes matching it with the stored pattern for the
authorised user obtaining a similarity value between them. A matching algorithm
and a deep analysis of similarity metrics performance is presented. The
semantic information added for the feature points allows to reduce the
computation load in the matching process as only points classified equally can
be matched. The system is capable of establishing a safe confidence band in the
similarity measure space between scores for patterns of the same individual and
between different individuals. Keywords: Verification system; Similarity measure; Retinal images; Biometric pattern; Feature points matching | |||
| A multiexpert collaborative biometric system for people identification | | BIBAK | Full-Text | 91-100 | |
| Maria De Marsico; Michele Nappi; Daniel Riccio; Genny Tortora | |||
| Present identification through single-biometric systems suffer from a number
of limitations, due to the fact that no single bodily or behavioral feature is
able to satisfy at the same time acceptability, speed and reliability
constraints of authentication in real applications. Multibiometric systems can
solve a number of problems of single-biometry approaches. A crucial issue to be
investigated relates to how results from different systems should be evaluated
and fused, in order to obtain an as reliable as possible global response. A
further source of flaws for present systems, both single-biometric and
multibiometric, can be found in the lack of dynamic update of parameters, which
does not allow them to adapt to changes in the working settings. They are
generally calibrated once and for all, so that they are tuned and optimized
with respect to specific conditions. In this work, we investigate an
architecture where single-biometry subsystems work in parallel, yet exchanging
information at fixed points, according to the N-Cross Testing Protocol. In
particular, the integrated subsystems work on the same biometric feature, the
face in this case, yet exploiting different classifiers. Notice that such
specific configuration is interesting to underline how the strengths of one
classifier can compensate for flaws of other classifiers, so that the final
result is more accurate and reliable. Moreover, parameters of each subsystem
are also dynamically optimized according to the behavior of all the others.
This is achieved by an additional component, the supervisor module, which
analyzes the responses from all subsystems and modifies the degree of
reliability required from each of them to accept the respective responses. In
this way subsystems collaborate at a twofold level, both for returning a common
answer and for tuning to changing operating conditions. The paper explores the
combination of these two novel approaches, demonstrating that component
collaboration increases system accuracy and allows identifying unstable
subsystems. Keywords: Biometric systems; Score fusion; Supervised reliability indexes | |||
| Group-specific face verification using soft biometrics | | BIBAK | Full-Text | 101-109 | |
| Gian Luca Marcialis; Fabio Roli; Daniele Muntoni | |||
| Soft biometrics have been recently proposed for improving the verification
performance of biometric recognition systems. Examples of soft biometrics are
skin, eyes, hair colour, height, and ethnicity. Some of them are often cheaper
than "hard", standard biometrics (e.g., face and fingerprints) to extract. They
exhibit a low discriminant power for recognizing persons, but can add some
evidences about the personal identity, and can be useful for a particular set
of users. In particular, it is possible to argue that users with a certain high
discriminant soft biometric can be better recognized. Identifying such users
could be useful in exploiting soft biometrics at the best, as deriving an
appropriate methodology for embedding soft-biometric information into the score
computed by the main biometric.
In this paper, we propose a group-specific algorithm to exploit soft-biometric information in a biometric verification system. Our proposal is exemplified using hair colour and ethnicity as soft biometrics and face as biometric. Hair colour and information about ethnicity can be easily extracted from face images, and used only for a small number of users with highly discriminant hair colour or ethnicity. We show by experiments that for those users, hair colour or ethnicity strongly contributes to reduce the false rejection rate without a significant impact on the false acceptance rate, whilst the performance does not change for other users. Keywords: Biometrics; Soft biometrics; Face verification | |||
| Towards realism in drawing areas of interest on architecture diagrams | | BIBAK | Full-Text | 110-128 | |
| Heorhiy Byelas; Alexandru Telea | |||
| Areas of interest (AOIs) are defined as groups of elements of system
architecture diagrams that share some common property. Visualizing AOIs is a
useful addition to plain diagrams, such as UML diagrams. Some methods have been
proposed to automatically draw AOIs on UML diagrams. However, it is not clear
whether actual users perceive the results of such methods to be better or worse
as compared to human-drawn AOI, and what needs to be improved. We present here
a process of studying and improving the perceived quality of computer-drawn
AOI. For this, we conducted a qualitative evaluation that delivered insight in
how users perceive the quality of computer-drawn AOIs as compared to hand-drawn
diagrams. Following these results, we derived and implemented several
improvements to an existing algorithm for computer-drawn AOIs. Next, we
designed a distance metric to quantitatively compare different AOI drawings,
and used this metric to show that our improved rendering algorithm creates
drawings which are closer to (good) human drawings than the original rendering
algorithm. We present here the results of the user evaluation, our improved
algorithm for drawing AOIs, and the quantitative analysis performed to compare
different drawings. The combined user evaluation, algorithmic improvements, and
quantitative comparison method support our claim of having improved the
perceived quality and understandability of AOI rendered on architecture
diagrams. Keywords: UML diagrams; Software visualization; Information visualization; Empirical evaluations; Visual shape comparison | |||
| Introduction to the special issue on Advances in Multimodal Biometric Systems | | BIB | Full-Text | 129-130 | |
| Michele Nappi; Genny Tortora | |||
| Computational methods for modeling facial aging: A survey | | BIBAK | Full-Text | 131-144 | |
| Narayanan Ramanathan; Rama Chellappa; Soma Biswas | |||
| Facial aging, a new dimension that has recently been added to the problem of
face recognition, poses interesting theoretical and practical challenges to the
research community. The problem which originally generated interest in the
psychophysics and human perception community has recently found enhanced
interest in the computer vision community. How do humans perceive age? What
constitutes an age-invariant signature that can be derived from faces? How
compactly can the facial growth event be described? How does facial aging
impact recognition performance? In this paper, we give a thorough analysis on
the problem of facial aging and further provide a complete account of the many
interesting studies that have been performed on this topic from different
fields. We offer a comparative analysis of various approaches that have been
proposed for problems such as age estimation, appearance prediction, face
verification, etc. and offer insights into future research on this topic. Keywords: Age progression; Age estimation; Craniofacial growth; Face recognition | |||
| Linguistics and face recognition | | BIBAK | Full-Text | 145-155 | |
| Harry Wechsler | |||
| We describe in this paper a novel biometric methodology for face recognition
suitable to address pose, illumination, and expression (PIE) image variability,
temporal change, flexible matching, and last but not least occlusion and
disguise that are usually referred to as denial and deception. The adverse
conditions listed above affect the scope and performance of biometric analysis
vis-à-vis both training and testing. The conceptual framework proposed
here draws support from discriminative methods using likelihood ratios. At the
conceptual level it links forensics and biometrics, while at the implementation
level it links the Bayesian framework and statistical learning theory. As many
of the concerns listed usually affect only parts of the face, a non-parametric
recognition-by-part approach is advanced here for the purpose of reliable face
recognition. Recognition-by-parts facilitates authentication because it does
not seek for explicit invariance. Instead, it handles variability using
component-based configurations that are flexible enough to compensate among
others for limited pose changes, if any, and limited occlusion and disguise.
The recognition-by-parts approach proposed here supports incremental and
progressive processing. It is similar in nature to modern linguistics and
practical intelligence with the emphasis on semantics and pragmatics. Layered
categorization starts with face detection using implicit rather than explicit
segmentation. It proceeds with face authentication that involves feature
selection of local patch instances including dimensionality reduction,
exemplar-based clustering of patches into parts, and data fusion for matching
using boosting driven by parts that play the role of weak learners. The
implementation, driven by transduction, employs proximity and typicality
(ranking) realized using strangeness and random deficiency p-values,
respectively. The feasibility and reliability of the proposed architecture has
been validated using FERET and FRGC data. The paper concludes with suggestions
for augmenting and enhancing the scope and utility of the recognition-by-parts
architecture. Keywords: Authentication; Biometrics; Boosting; Clustering; Cross-validation; Data fusion; Face recognition; Feature selection; FERET; Forensics; FRGC; ICA; k Nearest neighbor; Likelihood ratio; Linguistics; Margin; MDL; Multimodal integration; Neyman-Pearson; Occlusion; Recognition; p-Values; Parsing; Random deficiency; Ranking; Recognition-by-parts; Segmentation; SIFT; Strangeness; Surveillance; Transduction; Typicality | |||
| Normal maps vs. visible images: Comparing classifiers and combining modalities | | BIBAK | Full-Text | 156-168 | |
| Andrea Francesco Abate; Maria De Marsico; Stefano Ricciardi; Daniel Riccio | |||
| This work investigates face recognition based on normal maps, and the
performance improvement that can be obtained when exploiting it within a
multimodal system, where a further independent module processes visible images.
We first propose a technique to align two 3D models of a face by means of
normal maps, which is very fast while providing an accuracy comparable to
well-known and more general techniques such as Iterative Closest Point (ICP).
Moreover, we propose a matching criterion based on a technique which exploits
difference maps. It does not reduce the dimension of the feature space, but
performs a weighted matching between two normal maps. In the second place, we
explore the range of performances offered by different linear and nonlinear
classifiers, when applied to the normal maps generated from the above aligned
models. Such experiments highlight the added value of chromatic information
contained in normal maps. We analyse a solid list of classifiers which were
selected due to their historical reference value (e.g. Principal Component
Analysis) or to their good performances in the bidimensional setting (Linear
Discriminant Analysis, Partitioned Iterated Function Systems). Last but not
least, we perform experiments to measure how different ways of combining normal
maps and visible images can enhance the results obtained by the single
recognition systems, given that specific characteristics of the images are
taken into account. For these last experiments we only consider the classifier
giving the best average results in the preceding ones, namely the PIFS-based
one. Keywords: Face recognition; Normal maps; Multimodal biometrics | |||
| Robustness of multimodal biometric fusion methods against spoof attacks | | BIBAK | Full-Text | 169-179 | |
| Ricardo N. Rodrigues; Lee Luan Ling; Venu Govindaraju | |||
| In this paper, we address the security of multimodal biometric systems when
one of the modes is successfully spoofed. We propose two novel fusion schemes
that can increase the security of multimodal biometric systems. The first is an
extension of the likelihood ratio based fusion scheme and the other uses fuzzy
logic. Besides the matching score and sample quality score, our proposed fusion
schemes also take into account the intrinsic security of each biometric system
being fused. Experimental results have shown that the proposed methods are more
robust against spoof attacks when compared with traditional fusion methods. Keywords: Multimodal biometrics; Secure biometrics; Face recognition; Fingerprint | |||
| Person recognition using facial video information: A state of the art | | BIBAK | Full-Text | 180-187 | |
| Federico Matta; Jean-Luc Dugelay | |||
| In this article we propose a detailed state of the art on person recognition
using facial video information. We classify the existing approaches present in
the scientific literature between those that neglect the temporal information,
and those that exploit it even partially. Concerning the first category, we
detail the extensions to video data of: eigenfaces, fisherfaces, active
appearance models (AAMs), radial basis function neural networks (RBFNNs),
elastic graph matching (EGM), hierarchical discriminative regression trees
(HDRTs) and pairwise clustering methods. After that, we focus on the strategies
exploiting the temporal information, in particular those analysing: the facial
motion with optical flow, the evolution of facial appearance over time with
hidden Markov models (HMMs) or with various probabilistic tracking and
recognition approaches, and the head motion with Gaussian mixture models. Keywords: Person recognition; Person identification; Person authentication; Person verification; Video; Facial information; State of the art; Survey | |||
| Audio-visual human recognition using semi-supervised spectral learning and hidden Markov models | | BIBAK | Full-Text | 188-195 | |
| Wei Feng; Lei Xie; Jia Zeng; Zhi-Qiang Liu | |||
| This paper presents a multimodal system for reliable human identity
recognition under variant conditions. Our system fuses the recognition of face
and speech with a general probabilistic framework. For face recognition, we
propose a new spectral learning algorithm, which considers not only the
discriminative relations among the training data but also the generative models
for each class. Due to the tedious cost of face labeling in practice, our
spectral face learning utilizes a semi-supervised strategy. That is, only a
small number of labeled faces are used in our training step, and the labels are
optimally propagated to other unlabeled training faces. Besides requiring much
less labeled data, our algorithm also enables a natural way to explicitly train
an outlier model that approximately represents unauthorized faces. To boost the
robustness of our system for human recognition under various environments, our
face recognition is further complemented by a speaker identification agent.
Specifically, this agent models the statistical variations of fixed-phrase
speech using speaker-dependent word hidden Markov models. Experiments on
benchmark databases validate the effectiveness of our face recognition and
speaker identification agents, and demonstrate that the recognition accuracy
can be apparently improved by integrating these two independent biometric
sources together. Keywords: Face recognition; Speaker identification; Semi-supervised spectral learning; Hidden Markov models (HMMs) | |||
| Dialogue patterns -- A visual language for dynamic dialogue | | BIBAK | Full-Text | 196-220 | |
| J. Siegel; D. Szafron | |||
| A dynamic dialogue is a conversation in which each participant alternately
selects remarks based on a changing world state and in which each remark can
change the world state. Dynamic dialogues happen frequently as conversations
between a player character (PC) and a non-player character (NPC) in a computer
game. When it is the PC's turn to speak, the current game state is used to
filter the static set of remarks available to the PC to a contextually
appropriate subset that is made available to the player. Selecting a PC remark
then leads to a candidate set of NPC remarks as appropriate responses to the
PC. The world state is used to filter this set of remarks to a single remark,
which is used by the NPC as the reply. To construct a dynamic dialogue, an
author must not only create the remarks, but also write the code that
determines which remarks are available to both participants at any point in the
dialogue. We present "generative dialogue patterns" as a new visual language
for designing dynamic dialogues and generating the program code that is
necessary to select the appropriate remarks during the dialogue. We use a case
study from the computer games domain to evaluate the effectiveness of
generative dialogue patterns. Keywords: Dynamic dialogue; Computer game; Design pattern; Generative; Scripting | |||
| Special issue on selected papers from VL/HCC 2008: Guest Editors' introduction | | BIB | Full-Text | 221-222 | |
| Paolo Bottoni; Mary Beth Rosson | |||
| Codetrail: Connecting source code and web resources | | BIBAK | Full-Text | 223-235 | |
| Max Goldman; Robert C. Miller | |||
| When faced with the need for documentation, examples, bug fixes, error
descriptions, code snippets, workarounds, templates, patterns, or advice,
software developers frequently turn to their web browser. Web resources both
organized and authoritative as well as informal and community-driven are
heavily used by developers. The time and attention devoted to finding (or
re-finding) and navigating these sites is significant. We present Codetrail, a
system that demonstrates how the developer's use of web resources can be
improved by connecting the Eclipse integrated development environment (IDE) and
the Firefox web browser. Codetrail uses a communication channel and shared data
model between these applications to implement a variety of integrative tools.
By combining information previously available only to the IDE or the web
browser alone (such as editing history, code contents, and recent browsing),
Codetrail can automate previously manual tasks and enable new interactions that
exploit the marriage of data and functionality from Firefox and Eclipse. Just
as the IDE will change the contents of peripheral views to focus on the
particular code or task with which the developer is engaged, so, too, the web
browser can be focused on the developer's current context and task. Keywords: Software development; Development environment; Web browser; Human-computer interaction | |||
| AgentCubes: Incremental 3D end-user development | | BIBAK | Full-Text | 236-251 | |
| Andri Ioannidou; Alexander Repenning; David C. Webb | |||
| 3D game development can be an enticing way to attract K-12 students to
computer science, but designing and programming 3D games is far from trivial.
Students need to achieve a certain level of 3D fluency in modeling, animation,
and programming to be able to create compelling 3D content. The combination of
innovative end-user development tools and standards-based curriculum that
promotes IT fluency by shifting the pedagogical focus from programming to
design, can address motivational aspects without sacrificing principled
educational goals. The AgentCubes 3D game-authoring environment raises the
ceiling of end-user development without raising the threshold. Our formal user
study shows that with Incremental 3D, the gradual approach to transition from
2D to 3D authoring, middle school students can build sophisticated 3D games
including 3D models, animations, and programming. Keywords: Incremental 3D; Game design; Visual programming; End-user development; IT fluency; Computational thinking | |||
| Generic and reflective graph transformations for checking and enforcement of modeling guidelines | | BIBAK | Full-Text | 252-268 | |
| Elodie Legros; Carsten Amelunxen; Felix Klar; Andy Schürr | |||
| In the automotive industry, the model driven development of software, today
considered as the standard paradigm, is generally based on the use of the tool
MATLAB Simulink/Stateflow. To increase the quality, the reliability, and the
efficiency of the models and the generated code, checking and elimination of
detected guideline violations defined in huge catalogs has become an essential
task in the development process. It represents such a tremendous amount of
boring work that it must necessarily be automated. In the past we have shown
that graph transformation tools like Fujaba/MOFLON allow for the specification
of single modeling guidelines on a very high level of abstraction and that
guideline checking tools can be generated from these specifications easily.
Unfortunately, graph transformation languages do not offer appropriate concepts
for reuse of specification fragments -- a MUST, when we deal with hundreds of
guidelines. As a consequence we present an extension of MOFLON that supports
the definition of generic rewrite rules and combines them with the reflective
programming mechanisms of Java and the model repository interface standard Java
Metadata Interface (JMI). Keywords: Graph transformation; Generic rules; Reflection | |||
| Automatic detection of dimension errors in spreadsheets | | BIBAK | Full-Text | 269-283 | |
| Chris Chambers; Martin Erwig | |||
| We present a reasoning system for inferring dimension information in
spreadsheets. This system can be used to check the consistency of spreadsheet
formulas and thus is able to detect errors in spreadsheets.
Our approach is based on three static analysis components. First, the spatial structure of the spreadsheet is analyzed to infer a labeling relationship among cells. Second, cells that are used as labels are lexically analyzed and mapped to potential dimensions. Finally, dimension information is propagated through spreadsheet formulas. An important aspect of the rule system defining dimension inference is that it works bi-directionally, that is, not only "downstream" from referenced arguments to the current cell, but also "upstream" in the reverse direction. This flexibility makes the system robust and turns out to be particularly useful in cases when the initial dimension information that can be inferred from headers is incomplete or ambiguous. We have implemented a prototype system as an add-in to Excel. In an evaluation of this implementation we were able to detect dimension errors in almost 50% of the investigated spreadsheets, which shows (i) that the system works reliably in practice and (ii) that dimension information can be well exploited to uncover errors in spreadsheets. Keywords: Spreadsheet; Dimension; Unit of measurement; Static analysis; Inference rule; Error detection | |||
| Introduction to the special issue on multimodal interaction through haptic feedback | | BIB | Full-Text | 285-286 | |
| Maria De Marsico; Giuliana Vitiello | |||
| Enhancing personal communication with spatial haptics: Two scenario-based experiments on gestural interaction | | BIBAK | Full-Text | 287-304 | |
| Jani Heikkinen; Jussi Rantala; Thomas Olsson; Roope Raisamo; Jani Lylykangas; Jukka Raisamo; Veikko Surakka; Teemu Ahmaniemi | |||
| Haptic gestures and sensations through the sense of touch are currently
unavailable in remote communication. There are two main reasons for this: good
quality haptic technology has not been widely available and knowledge on the
use of this technology is limited. To address these challenges, we studied how
users would like to, and managed to create spatial haptic information by
gesturing. Two separate scenario-based experiments were carried out: an
observation study without technological limitations, and a study on gesturing
with a functional prototype with haptic actuators. The first study found three
different use strategies for the device. The most common gestures were shaking,
smoothing and tapping. Multimodality was requested to create the context for
the communication and to aid the interpretation of haptic stimuli. The second
study showed that users were able to utilize spatiality in haptic messages
(e.g., forward-backward gesture for agreement). However, challenges remain in
presenting more complex information via remote haptic communication. The
results give guidance for communication activities that are usable in spatial
haptic communication, and how to make it possible to enable this form of
communication in reality. Keywords: Haptics; Communication; Gestures; User study; Prototype; Scenarios | |||
| Vibrotactile feedback to aid blind users of mobile guides | | BIBAK | Full-Text | 305-317 | |
| Giuseppe Ghiani; Barbara Leporini; Fabio Paternò | |||
| In this work, we report on a solution for providing support to the blind
using mobile museum guides by exploiting the haptic channel as a complement to
the audio/vocal one. The overall goal is to improve the autonomy and social
integration of blind visitors. We followed an iterative approach in which the
proposed system went through various user evaluations and further refinements.
The final solution includes vibrotactile feedback enhancement for orientation
and obstacle avoidance obtained through the use of unobtrusive actuators
applied to two of the user's fingers combined with an electronic compass and
obstacle detector sensors connected wirelessly to the mobile guide. Our study
indicates that vibrotactile feedback is particularly useful to provide frequent
unobtrusive indications of useful dynamic information, such as the level of
proximity of an obstacle or the distance from the right orientation. Keywords: Mobile guide; Accessibility; Blind users; Vibrotactile feedback; Multi-modal user interfaces | |||
| A haptic-based approach to virtual training for aerospace industry | | BIBAK | Full-Text | 318-325 | |
| Andrea F. Abate; Mariano Guida; Paolo Leoncini; Michele Nappi; Stefano Ricciardi | |||
| In the last years, the industrial world has been increasingly adopting
computer-aided solutions for design for maintainability and maintenance
training tasks with the goal to reduce development costs and to shorten time,
and to improve product and service quality. Computer-based training systems
created to simulate machine assembly maintenance are normally operated by means
of ordinary human-computer interfaces (keyboard, mouse, etc.), but this usually
results in systems that are far from the real procedures, and therefore not
effective in terms of training. In this study, we show that a better solution
may come from the combination of virtual reality techniques and haptic
interaction. To this regard, we present the results of a research aimed at
testing and evaluating the effectiveness of the haptic feedback for
first-person maintenance tasks targeted to the aerospace industry. The proposed
system implements an interaction environment in which each of the main
maintenance activities can be simulated by the trainee exploiting a hand-based
commercial haptic device, operated by means of specific haptic-rendering
techniques to provide realistic feedbacks during manipulation. A usability
study is included to help assessing the potential of this approach. Keywords: Hand based haptic interaction; Computer based training; Haptic rendering | |||
| Toward multimodal notation for mathematics: Why and how | | BIBAK | Full-Text | 326-340 | |
| Cristian Bernareggi; Piero Mussio; Loredana Parasiliti Provenza | |||
| Notation is a tool of thought, recording and communicating concepts and
activities related to a domain of knowledge. In the history of mathematical
notation, written notation is usually considered. However, to be an effective
thinking tool, notation must be properly perceived. Blind and partially sighted
people run into difficulty in making, exploring and understanding mathematical
concepts conceived for being represented in multi-dimensional space. In this
paper, we capitalize on the multifaceted nature of digital symbols to define
multimodal digital notation for graph structures that allows blind and
partially sighted people to represent graph structures, reason about them and
communicate their reasoning with sighted people as well as each other. As
support tool for notation proposed we have designed a multimodal interactive
system, in which haptic signals play a crucial role. An evolutionary prototype
of the system has been developed and evaluated according to the star life cycle
model. Keywords: Multimodal notation; Visually impaired users; Haptic I/O; Interaction styles | |||
| Tactile feedback enhanced hand gesture interaction at large, high-resolution displays | | BIBAK | Full-Text | 341-351 | |
| Stephanie Foehrenbach; Werner A. König; Jens Gerken; Harald Reiterer | |||
| Human beings perceive their surroundings based on sensory information from
diverse channels. However, for human-computer interaction we mostly restrict
the user on visual perception. In this paper, we contribute to the
investigation of tactile feedback as an additional perception modality.
Therefore, we will first discuss existing user studies and provide a
classification scheme for tactile feedback techniques. We will then present and
discuss a comparative evaluation study based on the ISO 9241-9 [Ergonomic
requirements for office work with visual display terminals (VDTs) -- Part 9:
requirements for non-keyboard input devices, 2000]. The 20 participants
performed horizontal and vertical one-directional tapping tasks with hand
gesture input with and without tactile feedback in front of a large,
high-resolution display. In contrast to previous research, we cannot confirm a
benefit of tactile feedback on user performance. Our results show no
significant effect in terms of throughput (effective index of performance
(IPe)) and even a significant higher error rate for horizontal target alignment
when using tactile feedback. Based on these results, we suggest that tactile
feedback can interfere with other senses in a negative way, resulting in the
observed higher error rate for horizontal targets. Therefore, more systematic
research is needed to clarify the influencing factors on the usefulness of
tactile feedback. Besides these results, we found a significant difference in
favor of the horizontal target alignment compared with the vertical one in
terms of the effective index of performance (IPe), confirming the work by
Dennerlein et al. [Force feedback improves performance for steering and
combined steering-targeting tasks, in: CHI '00: Proceedings of the SIGCHI
Conference on Human Factors in Computing Systems, ACM, New York, NY, USA, 2000,
pp. 423-429]. Keywords: Hand gestures; Tactile feedback; Fitts' Law; Controlled experiment; Input device; Large high-resolution display | |||
| Audio-video biometric recognition for non-collaborative access granting | | BIBAK | Full-Text | 353-367 | |
| Christian Micheloni; Sergio Canazza; Gian Luca Foresti | |||
| In this paper, the problem of non-collaborative person identification for a
secure access to facilities is addressed. The proposed solution adopts a face
and a speaker recognition techniques. The integration of these two methods
allows to improve the performance with respect to the two classifiers.
In non-collaborative scenarios, the problem of face recognition first requires to detect the face pattern then to recognize it even when in non-frontal poses. In the current work, a histogram normalization, a boosting technique and a linear discrimination analysis have been exploited to solve typical problems like illumination variability, occlusions, pose variation, etc. In addition, a new temporal classification is proposed to improve the robustness of the frame-by-frame classification. This allows to project known classification techniques for still image recognition into a multi-frame context where the image capture allows dynamics in the environment. For the audio, a method for the automatic speaker identification in noisy environments is presented. In particular, we propose an optimization of a speech de-noising algorithm to optimize the performance of the extended Kalman filter (EKF). To provide a baseline system for the integration with our proposed speech de-noising algorithm, we use a conventional speaker recognition system, based on Gaussian mixture models and mel frequency cepstral coefficients (MFCCs) as features. To confirm the effectiveness of our methods, we performed video and speaker recognition tasks first separately then integrating the results. In particular, two different corpora have been used: (a) a public corpus (ELDSR for audio and FERRET for images) and (b) a dedicated audio/video corpus, in which the speakers read a list of sentences wearing a scarf or a full-face motorcycle helmet. Experimental results show that our methods are able to reduce significantly the classification error rate. Keywords: Face recognition; Face detection; Audio de-noising; Speaker recognition | |||
| Deriving topological relations between regions from direction relations | | BIBAK | Full-Text | 368-384 | |
| Luo Guo; Shihong Du | |||
| The integration of topological and direction relations plays an important
role in many applications, like spatial databases and pictorial retrieval
systems. The method for deriving composition of binary topological relations
cannot always yield unique or interesting results. Therefore, to integrate
efficiently topological and direction relations, some new mechanisms are
required to derive topological relations from direction cases when the above
situations occur. This paper presents the computation methods for deriving
topological relations from direction relations. The methods fall into two
categories: the derivation of topological relations from one direction relation
and two direction relations. Our methods can provide topological information
when topological relations are unavailable, or more precise results are
expected. Thus they are helpful in the integration of the calculi for
topological and direction relations. Keywords: Qualitative spatial reasoning; Topological relations; Direction relations; Direction relation matrix; 9-intersection model | |||
| Drawing graphs with nonuniform nodes using potential fields | | BIBAK | Full-Text | 385-402 | |
| Chun-Cheng Lin; Hsu-Chun Yen; Jen-Hui Chuang | |||
| Graphs with nonuniform nodes arise naturally in many real-world
applications. Although graph drawing has been a very active research in the
computer science community during the past decade, most of the graph drawing
algorithms developed thus far have been designed for graphs whose nodes are
represented as single points. As a result, it is of importance to develop
drawing methods for graphs whose nodes are of different sizes and shapes, in
order to meet the need of real-world applications. To this end, a potential
field approach, coupled with an idea commonly found in force-directed methods,
is proposed in this paper for drawing graphs with nonuniform nodes in 2-D and
3-D. In our framework, nonuniform nodes are uniformly charged, while edges are
modelled by springs. Using certain techniques developed in the field of
potential-based path planning, we are able to find analytically tractable
procedures for computing the repulsive force and torque of a node in the
potential field induced by the remaining nodes. The crucial feature of our
approach is that the rotation of every nonuniform node and the multiple edges
between two nonuniform nodes are taken into account. In comparison with the
existing algorithms found in the literature, our experimental results suggest
this new approach to be promising, as drawings of good quality for a variety of
moderate-sized graphs in 2-D and 3-D can be produced reasonably efficiently.
That is, our approach is suitable for moderate-sized interactive graphs or
larger-sized static graphs. Furthermore, to illustrate the usefulness of our
new drawing method for graphs with zero-sized nodes, we give an application to
the visualization of hierarchical clustered graphs, for which our method offers
a very efficient solution. Keywords: Graph drawing; Potential field | |||
| Node overlap removal in clustered directed acyclic graphs | | BIBAK | Full-Text | 403-419 | |
| Pushpa Kumar; Kang Zhang | |||
| Graph drawing and visualization represent structural information as diagrams
of abstract graphs and networks. An important subset of graphs is directed
acyclic graphs (DAGs). This paper presents a new E-Spring algorithm, extended
from the popular spring embedder model, which eliminates node overlaps in
clustered DAGs. In this framework, nodes are modeled as non-uniform charged
particles with weights, and a final drawing is derived by adjusting the
positions of the nodes according to a combination of spring forces and
repulsive forces derived from electrostatic forces between the nodes. The
drawing process needs to reach a stable state when the average distances of
separation between nodes are near optimal. We introduce a stopping condition
for such a stable state, which reduces equilibrium distances between nodes and
therefore results in a significantly reduced area for DAG visualization. It
imposes an upper bound on the repulsive forces between nodes based on graph
geometry. The algorithm employs node interleaving to eliminate any residual
node overlaps. These new techniques have been validated by visualizing eBay
buyer-seller relationships and has resulted in overall area reductions in the
range of 45-79%. Keywords: Graph visualization; Spring algorithm; Directed acyclic graphs; Node overlap | |||
| Phenomena -- A visual environment for querying heterogenous spatial data | | BIBAK | Full-Text | 420-436 | |
| Luca Paolino; Monica Sebillo; Genoveffa Tortora; Giuliana Vitiello; Robert Laurini | |||
| The need to perform complex analysis and decision making tasks has motivated
growing interest in Geographic Information Systems (GIS) as a means to compare
different scenarios and simulate the evolution of a phenomenon. However, data
and function complexity may critically affect human interaction and system
performances during planning and prevention activities. This is especially true
when the scenarios of interest involve continuous fields, besides discrete
objects.
In the present paper we describe the visual environment Phenomena, where continuous and discrete data may be handled through a uniform approach. We illustrate how users' activity is supported by a visual framework where they can interact with, manipulate and query heterogeneous data, with a very small training effort. A preliminary experimental study suggests that when users perform complex tasks, a higher usability degree may be achieved compared to the adoption of a textual spatial SQL. Keywords: Visual environments; Visual query languages; Geographic information systems; Continuous fields; Usability evaluation | |||