Abstract
Wireless Sensor Networks (WSNs) consist of small devices capable of sensing various variables in the environment, process and communicate them through the network. These devices interact together to carry out monitoring tasks. A photo-voltaic (PV) power plant is an example of such network, where each solar panel has a sensor connected to it. The number of interconnected solar panels can become very large in order to cover a large area. Each sensor senses the output of the panel and sends this value to a central node for processing. In this paper we study and compare the performance of a multi-hop wireless sensor network, employing a polling based data collecting technique with data aggregation, against the performance of a one hop network employing two different data collecting techniques. The study considers a wireless network with fixed number of nodes using different values of the offered load, estimating the network throughput for each technique and offered load. The use of a multi-hop setup was chosen in order to reduce transmission power and interference among nodes. Results show that the multi-hop network, using the polling based data collecting technique with data aggregation, performs close to the one hop network using the other two techniques. The study involves both simulation and testbed experimentation.

Abstract
Typical sensor networks are formed by low-end, battery operated devices, which rely on low-energy communication technologies, such as Bluetooth, Zigbee and ANT+, due to their energy efficiency. On the other hand, sensor networks increasingly need to be connected to the Internet, which implies adaptations of the TCP/IP stack to fit such wireless technologies. These adaptations bring additional complexity and imply new hardware, thus deployments are cumbersome and sub-optimal. Conversely, Wi-Fi is ubiquitous, can be seamlessly integrated with TCP/IP, and is energy-efficient with the right configurations; yet, its usage is still uncommon in e-health scenarios. For these reasons, we argue that a TCP/IP over Wi-Fi approach should be followed in e-health sensor networks. We propose a novel cross-layer, context-aware network configuration mechanism, which monitors the user and networking contexts and optimizes the configuration of the TCP/IP protocol stack accordingly. Our approach enables seamless integration between e-health wireless sensor networks and the TCP/IP backbone, while improving energy efficiency and reliability. © 2013 IEEE.

Abstract

Abstract
Creating descriptive labels for videos is an important task, with application in video retrieval, Web accessibility and computer vision. However automatic creation of such labels is difficult and, alternatively, having professionals manually describing content is too expensive. Engaging end-users in the process of describing multimedia assets may lead to good results and enables creating the sense of participation which is currently one of the key factors to attract customers to a service. The existing approaches are highly successful in terms of number of engaged players and number of collected labels, but hardly create comprehensive tag sets, contributing both with generic or too narrow meaning tags. "Games With A Purpose" are one of the approaches that have been used in an attempt to create comprehensive video descriptions by harnessing the intelligence of human players and have them contributing and collaborating towards a common goal that is recognized if successful. This paper describes a game which implements two mechanisms for collecting data via human-based computation games. Tags introduced by registered players, in a given timecode, are validated based on a collaborative scoring mechanism that eliminates irregular annotations. Additionally, a voting mechanism that enables players to endorse or refuse existing tags, provides an extra instrument to guarantee the quality of the annotations. © 2013 ACM.

Abstract
Immersive media has the potential for strong impact on users' emotions and their sense of presence and engagement. The main objective of this workshop is to bring together researchers, students, media producers, service providers and industry players in the area of emergent immersive media. The workshop will provide a platform for a deep discussion on ongoing work, recent achievements and experiences. It is expected not only to consolidate experiences but also to identify aspects where strong collaboration among all the interested players is needed and to point towards future working directions. Copyright © 2013 ACM.

Abstract