Effects of population size for location-aware node placement in WMNs: evaluation by a genetic algorithm--based approach

Wireless mesh networks (WMNs) are cost-efficient networks that have the potential to serve as an infrastructure for advanced location-based services. Location service is a desired feature for WMNs to support location-oriented applications. WMNs are also interesting infrastructures for supporting ubiquitous multimedia Internet access for mobile or fixed mesh clients. In order to efficiently support such services and offering QoS, the optimized placement of mesh router nodes is very important. Indeed, such optimized mesh placement can support location service managed in the mesh and keep the rate of location updates low...Peer ReviewedPostprint (author's final draft

A Communication Middleware for Ubiquitous Multimedia Adaptation Services

Ubiquitous services have gained increasing attention in the area of mobile communication aiming to allow service access anywhere, anytime and anyhow while keeping complexity to a minimum for both users and service providers. Ubiquitous environment features a wide range and an increasing number of access devices and network technologies. Context-aware content/service adaptation is deemed necessary to ensure best user experience. We developed an Adaptation Management Framework (AMF) Web Service which manages the complexity of dynamic and autonomous content adaptation and serves as an invisible enabler for ubiquitous service delivery. It remains challenging to manage the tasks involved in the communication between the AMF Web Service and the user's environment, typically represented by various types of intelligent agents. This work presents a middleware which manages those tasks and serves not only as a protocol gateway, but also as a message translator, a service broker, a complexity shield etc., between AMF Web Services and User Agents

A Communication Middleware for Ubiquitous Multimedia Adaptation Services

Ubiquitous services have gained increasing attention in the area of mobile communication aiming to allow service access anywhere, anytime and anyhow while keeping complexity to a minimum for both users and service providers. Ubiquitous environment features a wide range and an increasing number of access devices and network technologies. Context-aware content/service adaptation is deemed necessary to ensure best user experience. We developed an Adaptation Management Framework (AMF) Web Service which manages the complexity of dynamic and autonomous content adaptation and serves as an invisible enabler for ubiquitous service delivery. It remains challenging to manage the tasks involved in the communication between the AMF Web Service and the user's environment, typically represented by various types of intelligent agents. This work presents a middleware which manages those tasks and serves not only as a protocol gateway, but also as a message translator, a service broker, a complexity shield etc., between AMF Web Services and User Agents

TransparentHMD: Revealing the HMD User's Face to Bystanders

While the eyes are very important in human communication, once a user puts on a head mounted display (HMD), the face is obscured from the outside world's perspective. This leads to communication problems when bystanders approach or collaborate with an HMD user. We introduce transparentHMD, which employs a head-coupled perspective technique to produce an illusion of a transparent HMD to bystanders. We created a self contained system, based on a mobile device mounted on the HMD with the screen facing bystanders. By tracking the relative position of the bystander using the smartphone's camera, we render an adapting perspective view in realtime that creates the illusion of a transparent HMD. By revealing the user's face to bystanders, our easy to implement system allows for opportunities to investigate a plethora of research questions particularly related to collaborative VR systems

They Are All After You: Investigating the Viability of a Threat Model That Involves Multiple Shoulder Surfers

Many of the authentication schemes for mobile devices that were proposed lately complicate shoulder surfing by splitting the attacker's attention into two or more entities. For example, multimodal authentication schemes such as GazeTouchPIN and GazeTouchPass require attackers to observe the user's gaze input and the touch input performed on the phone's screen. These schemes have always been evaluated against single observers, while multiple observers could potentially attack these schemes with greater ease, since each of them can focus exclusively on one part of the password. In this work, we study the effectiveness of a novel threat model against authentication schemes that split the attacker's attention. As a case study, we report on a security evaluation of two state of the art authentication schemes in the case of a team of two observers. Our results show that although multiple observers perform better against these schemes than single observers, multimodal schemes are significantly more secure against multiple observers compared to schemes that employ a single modality. We discuss how this threat model impacts the design of authentication schemes

Brainatwork: Logging Cognitive Engagement and Tasks in the Workplace Using Electroencephalography

Today's workplaces are dynamic and complex. Digital data sources such as email and video conferencing aim to support workers but also add to their burden of multitasking. Psychophysiological sensors such as Electroencephalography (EEG) can provide users with cues about their cognitive state. We introduce BrainAtWork, a workplace engagement and task logger which shows users their cognitive state while working on different tasks. In a lab study with eleven participants working on their own real-world tasks, we gathered 16 hours of EEG and PC logs which were labeled into three classes: central, peripheral and meta work. We evaluated the usability of BrainAtWork via questionnaires and interviews. We investigated the correlations between measured cognitive engagement from EEG and subjective responses from experience sampling probes. Using random forests classification, we show the feasibility of automatically labeling work tasks into work classes. We discuss how BrainAtWork can support workers on the long term through encouraging reflection and helping in task scheduling

Integration of human factors in networked computing

This is the post-print version of the Article. The official published version can be accessed from the link below - Copyright @ 2008 Elsevie

GTmoPass: Two-factor Authentication on Public Displays Using Gaze-touch Passwords and Personal Mobile Devices

As public displays continue to deliver increasingly private and personalized content, there is a need to ensure that only the legitimate users can access private information in sensitive contexts. While public displays can adopt similar authentication concepts like those used on public terminals (e.g., ATMs), authentication in public is subject to a number of risks. Namely, adversaries can uncover a user's password through (1) shoulder surfing, (2) thermal attacks, or (3) smudge attacks. To address this problem we propose GTmoPass, an authentication architecture that enables Multi-factor user authentication on public displays. The first factor is a knowledge-factor: we employ a shoulder-surfing resilient multimodal scheme that combines gaze and touch input for password entry. The second factor is a possession-factor: users utilize their personal mobile devices, on which they enter the password. Credentials are securely transmitted to a server via Bluetooth beacons. We describe the implementation of GTmoPass and report on an evaluation of its usability and security, which shows that although authentication using GTmoPass is slightly slower than traditional methods, it protects against the three aforementioned threats