3,616 research outputs found
Content source selection in Bluetooth networks
Large scale market penetration of electronic devices equipped with Bluetooth technology now gives the ability to share content (such as music or video clips) between members of the public in a decentralised manner. Achieved using opportunistic connections, formed when they are colocated, in environments where Internet connectivity is expensive or unreliable, such as urban buses, train rides and coffee shops. Most people have a high degree of regularity in their movements (such as a daily commute), including repeated contacts with others possessing similar seasonal movement patterns. We argue that this behaviour can be exploited in connection selection, and outline a system for the identification of long-term companions and sources that have previously provided quality content, in order to maximise the successful receipt of content files. We utilise actual traces and existing mobility models to validate our approach, and show how consideration of the colocation history and the quality of previous data transfers leads to more successful sharing of content in realistic scenarios
Character Assassination: Amending Federal Rule of Evidence 404(B) to Protect Criminal Defendants
TRULLO - local trust bootstrapping for ubiquitous devices
Handheld devices have become sufficiently powerful
that it is easy to create, disseminate, and access digital content
(e.g., photos, videos) using them. The volume of such content is
growing rapidly and, from the perspective of each user, selecting
relevant content is key. To this end, each user may run a trust
model - a software agent that keeps track of who disseminates
content that its user finds relevant. This agent does so by
assigning an initial trust value to each producer for a specific
category (context); then, whenever it receives new content, the
agent rates the content and accordingly updates its trust value for
the producer in the content category. However, a problem with
such an approach is that, as the number of content categories
increases, so does the number of trust values to be initially set.
This paper focuses on how to effectively set initial trust values.
The most sophisticated of the current solutions employ predefined
context ontologies, using which initial trust in a given
context is set based on that already held in similar contexts.
However, universally accepted (and time invariant) ontologies
are rarely found in practice. For this reason, we propose a
mechanism called TRULLO (TRUst bootstrapping by Latently
Lifting cOntext) that assigns initial trust values based only on
local information (on the ratings of its user’s past experiences)
and that, as such, does not rely on third-party recommendations.
We evaluate the effectiveness of TRULLO by simulating its use
in an informal antique market setting. We also evaluate the
computational cost of a J2ME implementation of TRULLO on
a mobile phone
Middleware for mobile computing: awareness vs. transparency (position summary)
Middleware solutions for wired distributed systems cannot be used in a mobile setting, as mobile applications impose new requirements that run counter to the principle of transparency on which current middleware systems have been built. We propose the use of reflection capabilities and meta-data to pave the way for a new generation of middleware platforms designed to support mobility
Q-CAD: QoS and Context Aware Discovery framework for adaptive mobile systems
This paper presents Q-CALl, a resource discovery framework
that enables pervasive computing applications to discover
and select the resource(s) best satisfying the user
needs, taking the current execution context and quality-ofservice
(QoS} requirements into account. The available resources
are first screened, so that only those suirable to the
current execution context of the application will be considered;
the shortlisted resources are then evaluated against
the QoS needs of the application, and a binding is established
to the best available
Trust based collaborative filtering
k-nearest neighbour (kNN) collaborative filtering (CF), the widely successful
algorithm supporting recommender systems, attempts to relieve the problem
of information overload by generating predicted ratings for items users have not
expressed their opinions about; to do so, each predicted rating is computed based
on ratings given by like-minded individuals. Like-mindedness, or similarity-based
recommendation, is the cause of a variety of problems that plague recommender
systems. An alternative view of the problem, based on trust, offers the potential to
address many of the previous limiations in CF. In this work we present a varation of
kNN, the trusted k-nearest recommenders (or kNR) algorithm, which allows users
to learn who and how much to trust one another by evaluating the utility of the rating
information they receive. This method redefines the way CF is performed, and
while avoiding some of the pitfalls that similarity-based CF is prone to, outperforms
the basic similarity-based methods in terms of prediction accuracy
Towards a mobile computing middleware: a synergy of reflection and mobile code techniques
The increasing popularity of wireless devices, such as mobile phones, personal digital assistants, watches and the like. is enabling new classes of applications that present challenging problems to designers. Applications have to be aware of, and adapt to, frequent variations in the context of execution, such as fluctuating network bandwidth, decreasing batten, power, changes in location or device capabilities, and so on. In this paper, we argue that middleware solutions for wired distributed systems cannot be used in a mobile setting, as the principle of transparency that has driven their design runs counter to the new degrees of awareness imposed by mobility: We propose a synergy of reflection and code mobility as a means for middleware to give applications the desired level of flexibility to react to changes happening in the environment, including those that have not necessarily been foreseen by middleware designers. We ruse the sharing and processing of images as an application scenario to highlight the advantages of our approach
VOLARE: Adaptive Web Service Discovery Middleware for Mobile Systems
With the recent advent and widespread use of smart mobile devices, the flexibility and versatility offered by Service Oriented Architecture's (SOA) makes it an ideal approach to use in the rapidly changing mobile environment. However, the mobile
setting presents a set of new challenges that service discovery methods developed for nonmobile environments cannot address. The requirements a mobile client device will have
from a Web service may change due to changes in the context or the resources of the client device. In a similar manner, a mobile device that acts as a Web service provider will
have different capabilities depending on its status, which may also change dramatically during runtime. This paper introduces VOLARE, a middleware-based solution that will monitor the resources and context of the device, and adapt service requests accordingly. The same method will be used to adapt the Quality of Service (QoS) levels advertised by service providers, to realistically reflect each provider's capabilities at any given moment. This approach will allow for more resource-efficient and accurate service discovery in mobile systems and will enable more reliable provider functionality in mobile devices
Towards a Petri net Model for Graph Transformation Systems
Graph transformation systems (GTS) have been successfully proposed as a general, theoretically sound model for concurrency. Petri nets (PN), on the other side, are a central and intuitive formalism for concurrent or distributed systems, well supported by a number of analysis techniques/tools. Some PN classes have been shown to be instances of GTS. In this paper, we change perspective presenting an operational semantics of GTS in terms of Symmetric Nets, a well-known class of Coloured Petri nets featuring a structured syntax that outlines model symmetries. Some practical exploitations of the proposed operational semantics are discussed. In particular, a recently developed structural calculus for SN is used to validate graph rewriting rules in a symbolic way
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