In this study, we propose a novel, context-based, location-aware algorithm for identifying low-level micro-activities that can be used to derive complex activities of daily living (ADL) performed by home-care patients. This identification is achieved by gathering the location information of the target user by using a wearable beacon embedded with a magnetometer and inertial sensors. The shortcomings of beacon-signal stability and mismatch issues in magnetic-field sequences are overcome by adopting a hybrid, three-phase approach for deducing the locus of micro-activities and their associated zones in a smart home environment. The suggested approach is assessed in two different test environments, where the main intention is to map the location of a person performing an activity with pre-defined house landmarks and zones in the offline labeled database. In addition to the recognition of low-level activities, the proposed method also identifies the person's walking trajectory within the same zone or between different zones of the house. The experimental results demonstrate that it is possible to achieve centimeter-level accuracy for the recognition of micro-activities and to achieve the classification accuracy of 85% for trajectory prediction. These results are encouraging and imply that the collection of accurate low-level information for ADL recognition is possible using integration of inertial sensors, magnetic field and Bluetooth low energy (BLE) technologies from the wearable beacon without relying on other infrastructural sensors.

This paper presents an integrated bandwidth adaptation scheme for multimedia wireless networks using application utility functions. With the proposed scheme, each call in the network is assigned a utility function according to its adaptive characteristics. Depending on the network load the allocated bandwidth of ongoing calls are upgraded or degraded dynamically so that the achieved utility of the network is maximized. Appropriate call admission control and bandwidth reservation policies are also incorporated into the scheme to provide QoS guarantees to the new and handoff calls, respectively. Extensive simulation experiments have been conducted to evaluate the connection-level performance of the proposed scheme. Results show that our bandwidth adaptation scheme is effective in both increasing the utility and bandwidth utilization of wireless networks while keeping the call blocking and handoff dropping probabilities substantially low.

In this paper a novel cloud-based Emergency Warning System (EWS) is described, using India as a primary case study. India is a country with nearly two dozen officially recognized languages and divergent communication technologies spread across a large geographical area. As of yet, this diversity has made the deployment of a single nationwide EWS near impossible. To address this deficiency, we have developed an EWS with adaptation as a central design tenet. This adaptation occurs on three levels: Dissemination adaptation addresses civilians' heterogeneous communication technologies; information adaptation morphs warnings to best reflect the capabilities of these communication technologies and users; while presentation adaptation is used to render information to the user in the most appropriate manner. We have developed a full cloud-based prototype, including the full EWS infrastructure and a civilian Android app.

3 Acknowledgments 4 List of publications 5 List of figures 10 List of tables 12 List of acronyms and abbreviations 13 Chapter

Many software systems operate across different geographically distributed hardware platforms, operating systems and programming languages. Publish/subscribe based Message Oriented Middleware (MOM) provides loose coupling and an efficient, asynchronous and scalable way of communication. However, as the complexity of such systems increase, manual verification of reconfiguration policies becomes unrealistic. The task calls for automated means of proof-checking configuration information in order to improve the reliability of large-scale MOM systems. This paper proposes a new model checking approach with temporal logic specifications to design and verify a system configuration. Model checking is a powerful technique, however the creation of appropriate finite state models for the systems being checked are complex and difficult to use in practice by non-formalists. The research presented in this paper finds suitable abstractions that reduce the system to a finite state model. The tools we developed for the generation of such models can be easily used by non-formalists. The systems models created using our techniques manages state explosion thanks to the choices of our abstractions. An example of the use of our tools and techniques is presented for a 50 node MOM, where the reachability of all topics and the presence of loops are proof-checked.

The validation of a probabilistic fingerprinting approach for outdoor location estimation using received signal strength (RSS) from GSM base stations (BSs) is described. The proposed approach is compared with a traditional probabilistic algorithm for three different area partitioning methods. Two contrasting real environments are used for the comparisons: one is a city environment and the other one is a rural setting. For each test-bed, over 9000 data points are collected over 170,000 and 110,000 square meters respectively. For each environment, principal components analysis (PCA) is globally used to remove the least useful transmitters to avoid unnecessary calculations. Then each environment is partitioned into different clusters based on RSS. PCA is again used within each cluster. The proposed scheme retains accuracy by not losing the substantial RSS correlations in each cluster, but also accommodates the different RSS distributions in each cluster. The experimental results show that the positioning accuracy is significantly improved and our clustering scheme gives good support for location estimation.

This paper presents results for an approach for indoor location estimation that integrates received signal strength (RSS) data from both WiFi and GSM networks. Previous work has focused on relatively small indoor environments. In many potential applications, getting approximate location information, such as in which room the mobile user is, is adequate. A hierarchical clustering method is used to partition the RSS space. To choose the best transmitters in a partition, we assess the amount of RSS variance that is attributable to different base stations (BSs) or access points (APs) by transforming the RSS tuples into principal components (PCs). This allows us to retain most of the useful information of detectable transmitters in fewer dimensions. In our experiments, we collected WiFi and cellular RSS on the 2nd and 3rd-floor electronic engineering (EE) building in Queen Mary campus. The experiment results show that the proposed method can provide a good accuracy of room prediction, especially when we integrate WiFi RSS with GSM RSS together to do the positioning.

In recent years, there has been an upsurge of research interest in cooperative wireless communications in both academia and industry. This article presents a simple overview of the pivotal topics in both mobile station (MS)- and base station (BS)- assisted cooperation in the context of cellular radio systems. Owing to the ever-increasing amount of literature in this particular field, this article is by no means exhaustive, but is intended to serve as a roadmap by assembling a representative sample of recent results and to stimulate further research. The emphasis is initially on relay-base cooperation, relying on network coding, followed by the design of cross-layer cooperative protocols conceived for MS cooperation and the concept of coalition network element (CNE)-assisted BS cooperation. Then, a range of complexity and backhaul traffic reduction techniques that have been proposed for BS cooperation are reviewed. A more detailed discussion is provided in the context of MS cooperation concerning the pros and cons of dispensing with high-complexity, power-hungry channel estimation. Finally, generalized design guidelines, conceived for cooperative wireless communications, are presented.

A probabilistic approach for outdoor location estimation using GSM received signal strength (RSS) from base stations (BSs) is presented. The proposed approach first divides the region of interest into different clusters based on deviations from the path loss model for each RSS component. In each cluster, the proposed algorithm uses principal component analysis (PCA) to intelligently transform RSS into new uncorrelated dimensions. This retains accuracy by not losing the substantial RSS correlations in each cluster, but also accommodates the different RSS distributions in each cluster. Our experiments are conducted in a real GSM outdoor environment. The proposed approach is compared with a traditional probabilistic algorithm for three different area partitioning methods. The experimental results show that the positioning accuracy is significantly improved and our clustering scheme gives good support for location estimation. Furthermore, it also can be concluded that the clustering scheme created by using deviation RSS based on Mahalanobis distance performs better than that using deviation based on Euclidean distance in a complex environment. What's more, the proposed method can reduce the number of training data used while maintaining the accuracy required.

Information-centric networks (ICNs) have emerged as a prominent future Internet architecture. They work on the principle that, in today's society, a network should be optimised towards the delivery of information, rather than the transit of messages between pre-determined end hosts. At the same time, another prominent research direction has been the delay-tolerant networking initiative, which argues that networks must explicitly support the tolerance of high delays and disruptions in end-to-end paths. We believe that this observation is pervasive across a number of applications and network technologies and should therefore be strongly considered in any future ICN designs. This paper explores the potential of combining these concepts into an information-centric delay-tolerant network (ICDTN). Through a qualitative and quantitative investigation, we present arguments in favour of the design, as well as important research challenges.

To increase frequency efficiency in cellular communication networks, this paper describes a cell coloring based distributed frequency allocation approach (C-DFA) for all kinds of cellular networks. C-DFA has high computational efficiency and is simpler to realize than other distributed approaches. Building on C-DFA, a distributed dynamic fractional frequency allocation (DDFFA) algorithm is designed for IEEE 802.16j supported Relay Based Cellular Networks (RBCN). It is shown that: a) C-DFA can better realize frequency efficiency and network resilience compared to centralized traditional distributed frequency allocation approach. b) DDFFA can significantly increase frequency efficiency to provide high capacity and throughput to the RBCN though at the cost of extra computation and BS-BS communication. The evaluations and analysis are based on moderate and high user congestion RBCN scenarios.

—Typical environment crisis messaging systems, e.g., those used in Tsunami Early Warning Systems, are open, distributed, and heterogeneous. In such systems, Publish Subscribe Message Oriented Middleware (PSMOM) is widely deployed using message brokers to enable open and distributed data publishers and subscribers to exchange raw and processed sensor data, authority driven workflows, and information generated by citizens. A key security challenge is that such message brokers may suffer a Denial of Service (DoS) attack, becoming overloaded and resulting in performance degradation or even worse in a broker crash. This significantly decreases the effectiveness of the system as vital messages may face unexpected delays or become lost. In order to address this challenge, a resilient workload management framework is required to better redistribute the message exchange from overloaded brokers to brokers with lesser loads. However, existing workload management mechanisms are not suitable to manage load in such environment crisis messaging systems as they are not designed to handle message traffic that may have different Quality of Service (QoS) requirements, e.g., different end-to-end transmission latency requirements. These may cause unexpected delays for sensitive messages or trigger unnecessary load balancing. In this paper, we propose a resilient delay sensitive workload management framework that extends an existing state-of-the-art messaging system, Publish/Subscribe Efficient Event Routing (PEER), by adding support for workload allocation, a Queue Depth load metric, and dynamic load thresholds, enabling end-to-end latency guarantees and avoiding unnecessary load balancing. The model has been validated in a simulation.

One approach to location estimation constructs a radio map of received signal strength (RSS) measurements at different known locations. However, location-based systems that depend on RSS alone are susceptible to inaccuracies caused by several factors, such as changes in humidity, temperature, the number of users and the physical environment. In this paper, we present a novel algorithm in which one radio map is generated as a reference map and adjusted for different run-time environmental conditions. A small sample of new RSS samples for the new environment is collected, with locations, and used to build a model to calibrate new measurements to the reference radio map. The calibration is not uniform and depends on the observed RSS. The effectiveness of the proposed method is demonstrated using real GSM data sets collected from a three-day music festival in London Victoria Park. Results are presented with and without applying the correction. A state-of-the-art cluster-based deterministic location estimation algorithm is used throughout.

An improvement to outdoor fingerprint location estimation based on clustering received signal strength (RSS) from base stations (BSs) is presented. The novel features that contribute to the greater accuracy are the use of deviations from the path loss model for each RSS component rather than the raw RSS for clustering; the accurate estimation of the cluster membership probability; the optimized trade-off between cluster size and accuracy of cluster modeling; and clusters are invariant to the BS or relay station (RS) power.

This paper looks at ways to improve resilience and reliability in Message-Oriented-Middleware. An abstract model of the broker was created and forms the basis of measuring the performance of the broker. An ARX model of the broker's performance is created and this model is used for bottleneck detection.

In order to provide a more resilient communication for a Neighborhood Watch type (NHW) system, a mobile middleware architecture using delay-tolerant network (DTN) technology and publish/subscribe concepts is described. The purpose of the middleware is to add resilience and reach to wireless communications, and also to reduce the battery drainage of the mobile devices, hence extending their operational lifetime. A prototype developed on the Android mobile platform is presented and the effects of multiple radio access, routing algorithm and application activity on energy efficiency are investigated.

The publish/subscribe paradigm is used to support a many-to-many model that allows an efficient dissemination of messages across a distributed system. Message Oriented Middleware (MOM) is a middleware that provides an asynchronous method of passing information between networked applications. MOMs can be based on a publish/subscribe model, which offers a robust paradigm for message delivery. This paper is concerned with this specific type of MOM. Recently, systems using MOMs have been used to integrate enterprise systems over geographically distributed areas, like the ones used in financial services, telecommunication applications, transportation and health-care systems. However, the reliability of a MOM system must be verified as well as the guarantees of delivery and reachability to all intended destinations. This paper provides a suitable way of checking the configuration of a publish/subscribe MOM system by building a model and using Linear-time Temporal Logic and Computation Tree Logic rules to verify certain constraints. In addition a code generator and a sub-paths detector are implemented to make the system checking more user-friendly and efficient.

To achieve high data rates and seamless coverage, radio access networks continue to increase in complexity, and the expenditure on operational tasks continues to rise to unprecedented levels. The development of Long Term Evolution (LTE) with Self-organizing network (SON) functions is being considered as an effective way to tackle these challenges. The paper describes an approach to model the coverage areas so that resource allocation algorithms can benefit from traffic distribution and coverage information. The main problem considered in this paper is the partitioning of the wireless environment into regions that allow for accurate modelling of the propagation environment and prediction of the traffic distribution. The analysis is based on models constructed from historical data and monitoring of the received signal strengths from the mobile stations (MSs). The mechanism is based on the similarity of perceived signals from MSs. The performance is evaluated using data generated from a network planning tool for a real environment.

Cellular networks provide a range of communication services and are the principal wireless technology for domestic and business users. However, in cellular networks, an accident or a storm or a malicious action may cause a base station to fail and so be unable to provide radio coverage to sections of users. Such base station failures also might result in user congestion to nearby operational base stations. Delay Tolerate Network (DTN) is used here to mitigate these problems. DTN enables user devices to self-organize to connect to functional base stations or other users through multiple hops. This paper augments DTN routing using geographic routing and Ant Colony Optimization (ACO) methods to enhance user to base station connection and network load balancing. Three DTN routing protocols: Epidemic, Binary Spray and Wait, and PRoPHET are considered in this paper. Compared to the geographic method described, the ACO does not require users and base stations to provide their geographic location, which is more appropriate to the context in which such an approach might be applied.