Computer Science and Engineering

In this work, we present a method for controlling call alert functionality in mobile phones. It has happened for almost everybody experiencing a situation that  call  alert functionality is not proper for actual  ambient  context, leading to missing a phone call or disturbing others by a loud ring. In this work, we use audio and physical movement analysis to  distinguish between  different situations in which a mobile phone may ring, and adjust the call alert functionality accordingly.  Considering the fact that mobile phones are usually carried in a pocket or bag, capturing ambient audio is not usually practically perfect. The novelty in our work is using information about physical movements of user of mobile device in addition to analysis of ambient audio. Analysis of user movements is based on information captured by acceleration sensors integrated in mobile phone. The call alert functionality is then adjusted based on a combination of ambient audio level and physical activities of user.

In this work, we present a new technique for efficient use of 3D space around a mobile device for interaction with the device. Around Device Interaction (ADI) enables extending interaction space of small mobile and tangible devices beyond their physical boundary. Our proposed method is based on using compass (magnetic field) sensor integrated in mobile devices (e.g. iPhone 3GS, G1 Android).  In this method, a properly shaped permanent magnet (e.g. in the shape of a rod, pen or a ring) is used for interaction. The user makes coarse gestures in the 3D space around the device using the magnet. Movement of the magnet affects the magnetic field sensed by the compass sensor integrated in the device. The temporal pattern of the gesture is then used as a basis for sending different interaction commands to the mobile device.  Zooming, turning pages, accepting/rejecting calls, clicking items, controlling a music player, and game interaction are some example use cases. The proposed method does not impose changes in hardware specifications of the mobile device, and unlike optical methods is not limited by occlusion problems.

In this work, we present a  new approach for text  (mainly digit) entry based on digit shaped gestures created in 3D space around a mobile  device. Some new mobile devices such as Apple iPhone 3GS and Google Android are equipped with magnetic (compass) sensor. The main idea is to influence the magnetic sensor using a magnet taken in hand. The user  draws  (writes)  digits in the 3D space around the device using the magnet taken in hand. Movement of  the magnet changes temporal pattern of magnetic field  around the device which is sensed and  registered by the magnetic (compass) sensor. The registered pattern is then compared against already recorded templates for different digits. Such a text (digit) entry approach can be especially useful for small mobile devices in which it is hard to operate small buttons or touch screen. Using our technique, the text entry space extends beyond physical boundaries of the device. A demonstrator for this approach is  implemented on Apple iPhone 3GS platform. It demonstrates registering a few templates for different digits, and recognizing digits written in the space around the device.

We present a new technique based on using embedded compass (magnetic) sensor for efficient use of 3D space around a mobile device for interaction with the device. Around Device Interaction (ADI) enables  extending interaction space of small mobile and tangible devices beyond their physical boundary. Our proposed method is based on using compass (magnetic field) sensor integrated in  new  mobile devices (e.g. iPhone 3GS, G1/2 Android).  In this method, a properly shaped permanent magnet (e.g. a rod, pen or a ring) is used for interaction. The user makes coarse gestures in 3D space around the device using the magnet. Movement of the magnet affects magnetic field sensed by the compass sensor integrated in the device. The temporal pattern of the gesture is then used as a basis for sending different interaction commands to  the mobile device. The proposed method does not impose changes in hardware  and physical  specifications of the mobile device, and unlike optical methods is not limited by occlusion problems. Therefore,  it  allows for efficient use of 3D space around device, including back of device. Zooming, turning pages, accepting/rejecting calls, clicking items, controlling a music player, and mobile game interaction are some example use cases.  Initial evaluation of our algorithm  using a prototype application developed for iPhone shows convincing gesture classification results.

For an enjoyable and  fun mobile entertainment software,  the user  interface need  to be usable, convenient, and  reliable; and the input controllers needs to be natural, intuitive and provide fast feedback on user's actions. In mobile context, most of entertainment applications currently use number pad, keypad, touch screen as input interaction modalities and devices are generally used  in outdoors with different noise conditions and  interruptions.  In addition  to  that, most of  the games require  complex  interactions  and  high  degree  of  collaboration  between  input  controllers;  thus,  users  often  have difficulties  on  concentrating  long  play  sessions while  trying  to  perform multiple  commands  simultaneously  using  the touch  screen.  For  that  reason,  there  exist  couple  of  mobile  phone  peripherals  for  external  input  to  enrich  the  user interaction;  however,  they  diminish  the  portability  of  these  devices.  In  this  work,  we  present  a  new  technique  for interaction with mobile entertainment software based on using magnetic field sensor integrated in mobile devices where a properly  shaped  permanent magnet  is  used  for  interaction. Our method  provides  a  powerful  interaction  technique  for mobile entertainment and it can be used both as a simple motion controller, as well as an intelligent gesture recognizer; therefore,  enable  players  to  input  larger  number  of  commands  simultaneously,  and  enhance  the  playability  and  the entertainment. The  proposed method  is  consistent with most  of  usability  and  playability  heuristics  defined  for mobile games and other mobile entertainment applications.

Digital  music  performance  require  high  degree  of interaction using natural, intuitive input controllers that provide fast feedback on user¡¯s action. One of the primary considerations of  professional  artists  is  a  powerful  and  creative  tool  that minimizes the number of steps required for the speed-demanding processes. Most  of  the musical performance  applications, which are  designed  for  mobile  devices,  use  touch-screen  or accelerometer as interaction modalities. In this work, we present a  novel  interface  for musical  performance  that  is  based  on  the magnetic  field  sensor  embedded  in  recent  mobile  devices.  The proposed  method,  at  this  point,  promises  a  new independent ground for  inputting momentary data during music composition and manipulation process. Giving the opportunity to freely, fully and  quickly  utilize  the  surrounding  3D  space,  it possesses the potential  to  bring  a  wide-spectrum  of  unique  options  for production and performance process of music.

In this paper, we present "MagiSign", a new user identification/authentication technique based on 3D magnetic signatures created in the space around a (mobile) device. The main idea is to influence magnetic (compass) sensor embedded in some mobile devices (e.g., iPhone 3GS, G1/2 Android) using a properly shaped magnet. The user draws 3D signatures  in the 3D space around the device using a magnet (e.g., pen, rod,  ring shaped). This is what we call as "3D Magnetic Signature". The temporal pattern of change in the magnetic field around the device is sensed and registered by the internally embedded magnetic  sensor. For  authentication/identification, new magnetic signature samples are compared with models created based on registered signatures. As the magnetic signature can be flexibly created in 3D space, it provides a wider choice for authentication. Unlike regular signatures, a hardcopy can not be  easily generated resulting  in higher  security. "MagiSign" technique does not require expensive or complex hardware/algorithm,  and  does  not imposemajor change in hardware or physical specifications of the device.It can be especially suitable for small mobile devices.

Playing musical instruments such as chordophones, percussions and keyboard types accompany with harmonic  interaction of player's hand with the instruments. In this work, we present a novel approach that enables the user to imitate the music playing gestures around mobile devices. In our approach, touch-less gestures, which change  magnetic field around the device, are employed for  interaction. The activity of playing an instrument can be transparently pursued by moving a tiny magnet  in hand around new generation of mobile phones equipped with embedded digital compass (magnetic sensor). The phonation intentions of the user can  be simulated on the mobile device by capturing the gestural pattern using magnetic sensor. The proposed method allows digital imitation of a broad number of instruments while still being able to sense musical hits and relative plectrum gestures. It provides a framework for extending interaction space with music applications beyond physical boundaries of small mobile devices, and to 3D space around the device. This can allow for a more natural, comfortable and flexible interaction. We present several mobile music applications developed based on the proposed method for Apple iPhone 3GS.

Real-time rendering of large animated crowds
consisting thousands of virtual humans is important for several
applications including simulations, games and interactive
walkthroughs; but cannot be performed using complex
polygonal models at interactive frame rates. For that reason,
several methods using large numbers of pre-computed image-based representations, which are called as impostors, have
been proposed. These methods take the advantage of existing
programmable graphics hardware to compensate the
computational expense while maintaining the visual fidelity.
Making the number of different virtual humans, which can be
rendered in real-time, not restricted anymore by the required
computational power but by the texture memory consumed for
the variety and discretization of their animations. In this work,
we proposed an alternative method that reduces the memory
consumption by generating compelling intermediate textures
using image-morphing techniques. In order to demonstrate the
preserved perceptual quality of animations, where half of the
key-frames were rendered using the proposed methodology, we
have implemented the system using the graphical processing
unit and obtained promising results at interactive frame rates.

In this research, we propose a novel parallelizable architecture
for the optimization of various sound synthesis parameters. The
architecture employs genetic algorithms to match the parameters of different sound synthesizer topologies to target sounds. The fitness function is evaluated in parallel to decrease its convergence time. Based on the proposed architecture, we have implemented a framework using the SuperCollider audio synthesis and programming environment and conducted
several experiments. The results of the experiments have shown
that the framework can be utilized for accurate estimation of the sound synthesis parameters at promising speeds.

In this work, we have propose a novel design for a
basic mobile phone, which is focused on the essence of
mobile communication and connectivity, based on a
silent speech interface and auditory feedback. This
assistive interface takes the advantages of voice control
systems while discarding its disadvantages such as the
background noise, privacy and social acceptance. The
proposed device utilizes low-cost and commercially
available hardware components. Thus, it would be
affordable and accessible by majority of users including
disabled, elderly and illiterate people.

In ubiquitous computing environments, the information
processing is integrated into everyday objects that are
ideally small, inexpensive and wirelessly networked
devices. Contemporary human-computer interaction
models are not adequate to control miniaturized
devices, which are distributed throughout everyday life
and activities. This post-desktop model requires natural
gesture-based interaction with distributed devices in an
egocentric manner as opposed to the current devicecentric
interaction. In this work, we have utilized the
recently proposed touch-less gesture-based interaction
method based on magnetic field to provide a hardware
basis for a wearable input controller. Furthermore, we
have discussed how the proposed device can allow
natural interaction with other devices within a
ubiquitous computing environment such as personal
area network.

Digital music performance requires high degree
of interaction with input controllers that can provide fast
feedback on user's action. One of the primary considerations of professional artists is a powerful and creative tool that minimizes the number of steps required for the speed-demanding processes. Nowadays, mobile devices have become popular digital instruments for musical performance. Most of the applications designed for mobile devices use touch-screen, keypad or accelerometer as interaction modalities. In this work, we present a novel interface for musical performance that is based on a magnetic interaction between a user and a device. The proposed method constitutes a touch-less interaction modality that is based on the mutual effect between magnetic field surrounding a device and that of a properly shaped magnet. Extending the interaction space beyond the physical boundary of a device provides the user with higher degree of flexibility for musical performance which in turn can open doors to wide-spectrum of new functionalities in digital music performance and production.

In this work, we present our current results in analyzing the security of Android smartphones with a focus on its Linux side. Our results are not limited to Android, they are also applicable to Linux-based smartphones such as OpenMoko Neo FreeRunner. Our contribution in this work is three-fold. First, we analyze android framework and the Linux-kernel to check security functionalities. We survey well accepted security mechanisms and tools which can increase device security. We provide descriptions on how to adopt these security tools on Android kernel, and provide their overhead analysis in terms of resource usage. As open smartphones are released and may increase their market share similar to Symbian, they may attract attention of malware writers. Therefore, our second contribution focuses on malware detection techniques at the kernel level. We test applicability of existing signature and intrusion detection methods in Android environment. We focus on monitoring events on the kernel; that is, identifying critical kernel, log file, file system and network activity events, and devising efficient mechanisms to monitor them in a resource limited environment. Our third contribution involves initial results of our malware detection mechanism basing on static function call analysis. We identified approximately 105 Executable and Linking Format (ELF) executables installed to the Linux side of Android. We perform a statistical analysis on the function calls used by these applications. The results of the analysis can be compared to newly installed applications for detecting significant differences. Additionally, certain function calls indicate malicious activity. Therefore, we present a simple decision tree for deciding the suspiciousness of the corresponding application. Our
results present a first step towards detecting malicious applications on Android-based devices.

Smartphones are getting increasingly popular and several malwares appeared targeting these devices. General countermeasures to smartphone malwares are currently limited
to signature-based antivirus scanners which efficiently detect
known malwares, but they have serious shortcomings with new
and unknown malwares creating a window of opportunity for
attackers. As smartphones become host for sensitive data and
applications, extended malware detection mechanisms are necessary complying with the resource constraints. The contribution of this paper is twofold. First, we perform static analysis on the executables to extract their function calls in Android environment using the command readelf. Function call lists are compared with malware executables for classifying them with PART, Prism and Nearest Neighbor Algorithms. Second, we present a collaborative malware detection approach to extend these results. Corresponding simulation results are presented.

Our daily lives become more and more dependent upon smartphones due to their increased capabilities. Smartphones are used in various ways, eg for payment systems or assisting the lives of elderly or disabled people. Security threats for these devices become more and more dangerous since there is still a lack of proper security tools for protection.

ABSTRACT In this research, we propose a novel parallelizable architecture for the optimization of various sound synthesis parameters. The architecture employs genetic algorithms to match the parameters of different sound synthesizer topologies to target sounds. The fitness function is evaluated in parallel to decrease its convergence time. Based on the proposed architecture, we have implemented a framework using the SuperCollider audio synthesis and programming environment and conducted several experiments.