With the development of ubiquitous computing, recommendation systems have become essential tools in assisting users in discovering services they would find interesting. This process is highly dynamic with an increasing number of services, distributed over networks, bringing the problems of cold start and sparsity for service recommendation to a new level. To alleviate these problems, this paper proposes a hybrid service recommendation prototype utilizing user and item side information, which naturally constitute a heterogeneous information network (HIN) for use in the emerging ubiquitous consumer wireless world (UCWW) wireless communication environment that offers a consumer-centric and network-independent service operation model and allows the accomplishment of a broad range of smart-city scenarios, aiming at providing consumers with the “best” service instances that match their dynamic, contextualized, and personalized requirements and expectations. A layered architecture for the proposed prototype is described. Two recommendation models defined at both global and personalized level are proposed, with model learning based on the Bayesian Personalized Ranking (BPR). A subset of the Yelp dataset is utilized to simulate UCWW data and evaluate the proposed models. Empirical studies show that the proposed recommendation models outperform several widely deployed recommendation approaches.

This paper reports on the development of a novel cloud-based next generation networking (NGN) system prototype, built on the revolutionary concept for the realisation of the next phase of a NGN-based consumer-oriented wireless networking, founded on the key attributes of the Ubiquitous Consumer Wireless World (UCWW). Design aspects and potential societal impact are presented.

This paper presents a practical performance analysis of an orthogonal space-time block code (OSTBC) based multiple-input multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM) system in the presence of nonlinear power amplifiers (PAs). The equivalent single-input single-output (SISO) scalar model is introduced and this then is used to construct a model for the nonlinear MIMO-OFDM system. Based on an unique inter-modulation product (IMP) analysis, it is shown how the receiver signal-to-noise ratio (SNR) may be derived to a polynomial based function of the system operating point. It is also shown that expressions for the asymptotical behavior of this SNR, when the linear and highly nonlinear PA operations are applied, may also be derived. Based on these derivations, it is further shown that the optimal system operating point, which corresponds to the maximum receiver SNR and SEP lower bound, can be identified and be derived to a polynomial based expression. Additionally, a general expression for the different integral expressions of SEP for the phase shift keying (PSK) and quadrature amplitude modulation (QAM) signals is found. By means of these analytical results, it was found possible to advance analytical explanations of observed behaviour in simulations and also to provide a practical analysis of performance optimization of nonlinear MIMO-OFDM systems.

This paper presents an HTML5 mobile test (mTest) application for use in an agent-based mobile eLearning (mLearning) system. The application was developed based on the Sencha Touch framework. The mTest application receives XML data from a personal assistant agent on the client side and can work in different mobile operating system environments, such as iOS, Android, BlackBerry, Windows Phone, etc. The application is designed by means of the Model View Controller (MVC) design pattern, and is easy to maintain, test, and extend. Moreover, the mTest session is stored on the mLearning server side, which facilitates the handover from one user device to another during the service session, and enables an always best connected and best served (ABC&S) communication mode.

This paper presents an agent-based content adaptation middleware for use in a mobile eHealth (mHealth) system. The middleware was developed by utilizing an object-oriented database version of the Wireless Universal Resource FiLe (WURFL) Application Programming Interface (API) and integrated into a cloud system as means for facilitating an Always Best Connected and best Served (ABC&S) communication mode. A pure Java Wireless Abstraction Library (Java-WALL) tag and a lightweight Multi-Agent System (MAS) are presented. A number of design aspects associated with the middleware implementation are also highlighted.

This paper presents a personalized middleware for mobile eHealth (mHealth) services for use in the Ubiquitous Consumer Wireless World (UCWW). The middleware was developed based on the ISO/IEEE 11073 personal health data (PHD) standards. It works as a multi-agent system (MAS) to provide intelligent collection of physiological data from medical sensors attached to human body, and subsequent sending of gathered data to a log data node by utilizing the Always Best Connected and best Served (ABC&S) communication paradigm. A number of design issues associated with the middleware implementation are outlined.

This paper presents an intelligent, light-weight, distributed, Java-based framework for the provision of mobile services (mServices) within an Info Station-based mLearning environment. This is maintained by a light-weight HTTP container. A multi-agent system acts as a bridge between the mService applications and the mobile users. Implementation issues associated with the framework and details of the systems facilitation of context sensitivity and service content adaptation are also discussed.

This paper describes the design and implementation of an MIDP client application used for service discovery and association by means of wireless billboard channels (WBCs) in the emerging ubiquitous consumer wireless world (UCWW). A lightweight architecture, a smart personal assistance agent for communication with the iWBC content provider, an efficient object serialization mechanism and a novel user interface form container are set out. An approach towards running the WBC receiver in a flexible and intelligent way is elaborated.

This paper proposes an intelligent software architecture for the service layer of wireless billboard channels (WBCs), which facilitates the IP datacasting (IPDC) of services' advertisements in a ubiquitous consumer wireless world (UCWW). The new WBC service layer's architecture consists of three tiers: a service discovery and maintenance tier acting as a client-server distributed system for data collection and organization; an intelligent application tier holding all business logic and common application programming interfaces (APIs); and a multi-agent system tier maintaining the advertisement, discovery and association (ADA) agents' lifecycle. A message channel, a blackboard and a gateway agent are shared by all three tiers thus enabling ADA processing in a highly efficient way.

An agent-oriented middleware supporting context-aware mobile eLearning services provision is presented. The middleware architecture developed for a distributed InfoStation-based network established within a University campus is described in detail. A concept for the control and management of service sessions and communications scenarios is also presented.

The IMP distortion occurring with the amplification of OFDM signals through a nonlinear RF power amplifier (PA) is analysed with a view to establishing internal relations and impairment significance of different types and combinations - composition categories- of IMPS. Through this, a novel estimation method was deduced to calculate power spectral densities (PSD) of nonlinear distortion. This method also helps expose some PA independent and operating point (OP) independent characteristics of PSD of nonlinear distortion. The simulation and analysis is based on the use of an IEEE 802.11a OFDM signal and a nonlinear PA model is derived from envelope characteristic measurements of an X-band and S-band GaN power amplifier.

A software system architecture for context-aware mLearning service execution in an InfoStations environment established within a University Campus is presented. The main user scenarios affecting the context-aware service execution are described. The multi-agent nature of the InfoStationpsilas architecture receives particular attention.

For the new proposal of using digital video broadcasting for handheld terminals (DVB-H) as a broadcast platform for wireless billboard channels (WBCs), this paper1proposes to use classical Rayleigh fading channel modeling techniques to analyze the performance of such a broadcast platform for this usage. Effectively the performance figure of merit employed is the DVB-H transport stream packet error rate (TSPER). Some early performance results are found assuming a Rayleigh fading channel with a central chi-square distribution and utilizing a corresponding finite state Markov model (FSMM).

Orthogonal frequency division multiplexing (OFDM) systems are significantly sensitive to the nonlinear distortion caused by RF power amplifiers. Generally, nonlinear distortion of OFDM signals, which generates a huge number of inter-modulation products (IMPs), is treated as a macro phenomenon. In this paper, low order IMPs are classified into various categories by their composition and the characteristics of IMPs in each category is presented. Relationships between single IMP and nonlinear distortion are also explored. The popular Bessel-Fourier (BF) envelope model with associated three signal representation approaches are used as analysis tools. An IEEE 802.11a signal is used and the nonlinear envelope is measured from a GaN power amplifier.

Digital video broadcasting for handheld terminals (DVB-H) is a candidate platform for broadcasting wireless billboard channel (WBC) service advertisements to mobile terminals. The transport stream packet error rate (TS-PER) as a basic is employed to measure the performance of the physical layer of DVB-H. In this paper, a Rayleigh-lognormal (RL) fading channel and the corresponding finite state Markov model (FSMM) for analyzing the TS-PER are studied and a new SNR partition algorithm and method are proposed, with relevant FSMM parameters, designed especially for a DVB-H slow fading environment. Through it initial analytical and simulation results on TS-PER as a function of Doppler frequency and FSMM scaling parameter alpha and fading parameter beta are presented.

An InfoStation-based information system design for the provision of mobile services (mServices) within a Library domain is presented. The main library mServices developed, along with sample interactions among entities, is described. The creation, management and implementation of user profiles and user service profiles receive particular attention.

This paper focuses on the development of InfoStation multi-agent system architectures facilitating the provision of mobile eLearning (mLearning) services across a University Campus area. Generic models and development approaches are considered. Particular attention is paid to the eContent generation and interpretation, as well as to the specification of the system architecture required to provide the needed flexibility and adaptability according to the requirements of modern mLearning systems. The multiagent approach for the system implementation is also justified.

A comparative analysis of the functional design and standards' compliancy of elearning authoring/assembling tools and learning content management systems (LCMSs) is presented with a view of assessing how their functionality meets the requirements for robust development of elearning content that complies with the existing elearning standards and specifications. The standard reference model used as a basis for the comparative analysis is the sharable content object reference model (SCORM) of the advanced distributed learning (ADL) initiative. The results show up the strengths but also the inadequacies of existing products. The exercise is useful also in that it implicitly draws out, in a fairly systematic and detailed way, a range of strengths and attributes one would like to see in the functional design of a minimal comprehensive elearning authoring/assembling tool and LCMS.

This paper presents an InfoStation-based multi-agent system, which provides intelligent mobile eLearning (mLearning) services in a university campus area. The network architecture is outlined. A description of the adaptable mLecture service as well as a sample entity interaction is provided. Approaches to the implementation of this system are considered.

This paper proposes an architecture for a consumer-oriented incoming call connection (ICQ service provision, which will be an integral element of the recently proposed future ubiquitous consumer wireless world (UCWW). The main components and interfaces of the ICC service architecture are described and protocol candidates are suggested. A typical illustrative ICC service scenario is elaborated and an outline proposal for an experimental proof-of-concept testbed is set out.

This paper presents an InfoStation-based multi-agent system, which provides mobile eLearning (mLearning) services in a university campus area. A description of some of the mLearning services along with sample entities' interaction is provided. Technologies for delivering of these services are discussed, and approaches for the system implementation and structuring are considered

Abstract ‘Always Best Connected’ (ABC) is considered one of the main requirements for next generation networks. The ABC concept allows a person to have access to applications using the devices and network technologies that best suits his or her needs or profile at any time. Clearly, this requires the combination of a set of existing and new technologies, at all levels of the protocol stack, into one integrated system. In this paper, a considerable set of the technologies, that are expected to play a key role towards the ABC vision, are presented. Starting from a reference architecture, the paper describes the required enhancements at certain levels of a traditional protocol stack, as well as technologies for mobility and end‐to‐end Quality of Service (QoS) support. The paper concludes with a case study that reveals the advantages of the ABC concept. This article replaces a previously published version (Wireless Communications and Mobile Computing; 5(2): 175‐191. [DOI: 10.1002/wcm.207]). Retraction notice DOI: 10.1002/wcm.426 . Copyright © 2006 John Wiley & Sons, Ltd.

This paper discusses the application of metadata to SCORM-compliant e-learning content in the broader context of proposed content metadata application and packaging service (CMAPS) framework. The CMAPS framework is developed on the basis of a process model, for producing high-quality e-learning content, proposed by the Learning Systems Architecture Lab (LSAL) at Carnegie Mellon University. The original LSAL model is expanded by introducing a new sub-stage needed to better identification of assets comprising educational resources and easy creation of asset metadata. For the needs of CMAPS two new IEEE LOM metadata application profiles are created and their elements explained. Finally the proposed CMAPS framework is described and a brief overview of the expected functionality of its modules is present.

The development of a mobile distributed e-learning center (DeLC) with enhanced functionality, including two pilot mobile services, is described. Some DeLC re-engineering approaches to enhance the m-learning/m-teaching facilities available in a university campus are considered.

This paper proposes a new third-party AAA (3P-AAA) supporting architecture, with which to serve a more consumer-based business model (CBM) for fourth generation wireless world (4GWW). A new diameter 3P-AAA application is suggested as a base signaling protocol solution option to serve this architecture. The command and response messages necessary for this application are identified and elaborated

This paper is concerned with the application of the SDL-92 language supported by the SDT tool to produce a telecommunication product which interfaces with a public ISDN network. The paper reports on the specification to implementation work for this real-time software engineering application, with the particular focus on evaluating the effectiveness of an SDL language approach to design and implementation. The target application is an ISDN basic access services management unit located on the user's premises. The development included implementation of data link layer and network layer protocol software for implementation of both sides of an ISDN basic access interface, viz. TE and NT sides. To validate this SDL system design, apart from software simulations, the C code is generated and down-loaded onto the micro-controller in the target unit and for testing on a public ISDN.

An explanation is given of the application of the complex Bessel function series approximation model of the memoryless amplitude and phase characteristics of nonlinear devices. Confusion had arisen because of the choice of a value of a parameter in the approximating expression. The practice had been to choose this simply as though it was just an arbitrary constant which scales the input, or as an optimizing parameter in the effort to get a best fit of the approximation to the measured data. By examining the derivation of the particular approximation, a determining and important link between this parameter and the desired operating dynamic range of the nonlinear characteristic being approximated is shown. How values for this parameter are calculated in terms of input overdrive relative to device saturation is also shown. In examining the origin of the approximating expressions, an alternative and simpler derivation to that given by J.C. Fuenzalida et al. (1973) is presented that is based on the work of M.J. Eric et al. (1972).>