An EM-based algorithm for clustering data streams in sliding windows

Cluster analysis has played a key role in data understanding. When such an important data mining task is extended to the context of data streams, it becomes more challenging since the data arrive at a mining system in one-pass manner. The problem is even more difficult when the clustering task is considered in a sliding window model which requiring the elimination of outdated data must be dealt with properly. We propose SWEM algorithm that exploits the Expectation Maximization technique to address these challenges. SWEM is not only able to process the stream in an incremental manner, but also capable to adapt to changes happened in the underlying stream distribution.

Image indexing for learning content in a mobile learning environment

The outcome of this research is a hybrid system called Image Indexing for Mobile Phone (ID4MP). It was developed based on a new hybrid algorithm called Ferial's Hybrids Algorithm (FHSA). The system has a good feature of efficiency, accuracy and performance in retrieving and delivering learning content to students' mobile phones.

The mobile skilled workforce : optimising benefits for rural communities

Many small rural communities with ageing populations and limited opportunities for young people are not attracting skilled workers, but have a flow of skilled people through the community as locums, seasonal workers or contractors. This project investigated the question: how can rural communities capture maximum benefit from professional and other highly skilled workers in the context of an increasingly mobile and transitory workforce? It found that rural communities derive a wide range of benefits from mobile skilled workers. Effectiveness of the integration process determines the nature and extent of mobile skilled worker contribution to the community. Community settings that encourage and support mobile skilled worker integration are identified in terms of culture, leadership and interactional infrastructure. These same settings also influence mobile skilled worker retention in rural communities. Rural communities need to be proactive in matching worker and community characteristics, and this begins with the recruitment process. Mobile skilled workers need assistance and support to develop a primary social contract, and the process needs to be monitored. This is a community-wide responsibility and requires a coordinated, whole-of-community approach. This is the first Australian study to explore how rural communities can capture the advantages from highly skilled mobile workers. Rural communities that make the most of the available pool of skills can increase resilience, identification and uptake of opportunities such as new enterprises, good practice in natural resource management, enhanced social and leisure opportunities, and the quality and range of local services. The importance of this report is that it provides a broad range of strategies for rural communities wanting to know how to optimise the benefits they derive from mobile skilled workers, regardless of their location or rural industry base.

Journalism students' experience of mobile phone technology : implications for journalism education

This study investigates journalism students’ usage of mobile phone technology when they begin their university studies and considers the implications of these baseline data for journalism education. This paper reports on the findings of three consecutive annual surveys of first year journalism students about their use of the applications available on their mobile phones. The surveys confirm that as well as using their phones to text and call, many are making video calls and most have shot photos and videos on their phones by the time they arrive at university. Many are using their phones to send or publish these images. More than half of the students now go online on their mobile phones. This evidence will inform journalism educators seeking to update their teaching practices and curricula.

Negotiation strategy for mobile agent-based e-negotiation

Negotiation is a vital component of electronic trading. It is the key decision-making approach used to reach consensus between trading partners. Generally, the trading partners implement various negotiation strategies in an attempt to maximize their utilities. As negotiation strategies have impact on the outcomes of negotiation, it is imperative to have efficient negotiation strategies that truly maximize clients’ utilities. In this paper, we propose a multi-attribute mobile agent-based negotiation strategy that maximizes client’s utility. The strategy focuses on one-to-many bilateral negotiation. It considers different factors that have significant effect on the scheduling of various negotiation phases: offer collection, evaluation, negotiation, and bid settlement. The factors include offers expiry time, market search space, communication delays, processing queues, and transportation times. We reasoned about the correctness of the proposed negotiation strategy with respect to the existing negotiation strategies. The analysis showed that the proposed strategy boosts client’s utility, shortens negotiation time, and ensures adequate market search.

Maximum likelihood approach for tracking multiple mobile agents with a moving doppler radar system

Tracking mobile agents with a Doppler radar system mounted on a moving vehicle is considered in this paper. Dopplers modulated from mobile agents on the single frequency continuous wave signals are analyzed in order to estimate the positions and velocities of multiple mobile agents. The measurement noise is assumed to be Gaussian and the maximum likelihood estimation is utilized to enhance the localization accuracy.

Optimization-based formation of autonomous mobile robots

The formation of autonomous mobile robots to an arbitrary geometric pattern in a distributed fashion is a fundamental problem in formation control. This paper presents a new asynchronous, memoryless (oblivious) algorithm to the formation problem via distributed optimization techniques. The optimization minimizes an appropriately defined difference function between the current robot distribution and the target geometric pattern. The optimization processes are performed independently by individual robots in their local coordinate systems. A movement strategy derived from the results of the distributed optimizations guarantees that every movement makes the current robot configuration approaches the target geometric pattern until the final pattern is reached.

Network resilience in low-resource mobile wireless sensor networks

Wireless sensor networks (WSNs) are deployed in numerous mission critical applications in which the network needs to remain active for as long as possible while delivering quality information to a base station. However, WSNs suffer from a wide range of attacks due to their limited processing and energy capabilities. Their resiliency, however, depends on fast recovery from such attacks being achieved. In recent work, the authors developed and implemented clustering, reprogramming and authentication protocols involved in recovering stationary WSNs with low resources. In this paper, we determine the additional resources required in implementing these protocols in a mobile WSN.

We present recovery protocols on TinyOS motes for a low-resourced, mobile deployment. We describe the issues we encountered in the implementation. We present times, RAM and ROM needed to run the recovery protocols and compare these with the stationary case, demonstrating that the additional cost of reprogramming in a mobile WSN is less than 25% of that in a stationary WSN and the additional cost of re-clustering in a mobile WSN is less than 9% of that in a stationary WSN. Authentication has an insignificant cost increase.

Navigation of four-wheel-steering mobile robots using robust fault-tolerant sliding mode control

This paper addresses the leader-follower tracking problem of a four-wheel-steering robot subjected to nonlinear uncertainties. Two control laws have been developed, based on the adaptive sliding mode method and the adaptive input-output feedback linearization method. The proposed control schemes have been tested by means of simulations.