The paper analyzes from a technical point of view the search engine optimization (SEO) techniques and technologies, which lead to effective results up to date. More specifically, it examines the potential SEO alternatives, with ultimate target to increase the organic visitors of a website and climb it up on top of the ranking in respective search engine’s queries. The main problem every website’s owner has to solve is which of these SEO techniques have to be implemented in order to increase the organic traffic with the minimum budget. This paper aims to present the dominant SEO techniques and evaluate their effectiveness to organic traffic. This paper aims to present the way well-known websites apply SEO nowadays. Taking advantage of this information, Webmasters will know in advance which exactly SEO techniques should apply to their websites and in which specific order to gain higher search results, resulting to higher traffic.

In this paper we present the incompatibility and complexity problems in Web development when using JavaScript. We also demonstrate the solution given by transcompilers and/or languages that compile to JavaScript, but we also highlight the respective problems. Thus, we present our proposal, i.e, a meta-transcompiler, that targets to harmonize JavaScript-oriented web development and tight the feedback loop between web standards' editors and web developers, even during the transition period of work-in-progress specifications, such as the upcoming ECMAScript 6 “Harmony” specification.

The paper focuses on the dominant handoff algorithms in vehicular Radio-over-Fiber (RoF) networks at 60 GHz. We present in short the afore-mentioned handoff algorithms, i.e., the Traditional Handoff (THO), the Virtual Cellular Zone (VCZ), the Moving Extended Cell (MEC) and the Moving Extended N-Cells (MENC), respectively. Furthermore, we analyze the corresponding mathematical models regarding packet loss for each one of the above handoff algorithms and we finally realize a simulation study in order to verify the theoretical results and strengthen the performance evaluation study.

In this work we specify and develop a framework for assessing the students' approach in the thematic area of telecommunications service provision, based on Felder learning styles. The framework is designed as an extension on existing engineering tools, widely used in tertiary education.

We develop an analytical framework for the end-to-end (e2e) asymptotic performance of pilot-symbol assisted Mary phase-shift keying (M-PSK) dual-hop relaying communication networks. The relays use the selective-decode-and-forward protocol and are equipped with multiple receive antennas. Channel estimation per antenna branch is done based on the least-squares estimation technique by means of pilot symbols. Also, maximal-ratio combining and coherent detection are performed at the receiving end. Simple approximate average symbol error probability (ASEP) expressions are obtained for high signal-to-noise ratio (SNR) when M ≥2. Our analysis is generic enough to account for any frequency-flat, time-selective, and/or arbitrarily correlated fading channel model per hop. As a case study, we provide e2e M-PSK ASEP expressions considering arbitrarily correlated Nakagami fading channels. Moreover, the optimal power allocation is studied, while the cooperation-gain and diversity-order are extracted. Numerical results are finally presented to verify the accuracy of our asymptotic expressions.

We demonstrate a handover scheme for supporting high end-user mobility in a 60 GHz broadband picocellular radio-over-fiber network. The proposed scheme relies on a novel moving extended cell (MEC) concept which is based on user-centric virtual groups of adjacent cells that transmit the same data content to the user. The MEC concept utilizes a mechanism for restructuring the virtual multi-cell area according to the user's mobility pattern, so that a virtual antenna group moves together with the mobile user. A mathematical model is developed and performance evaluation is also conducted and presented, demonstrating zero packet loss and call dropping probability values in high-rate wireless services for a broad range of mobile speeds up to 40 m/sec and independently of the fiber link distances.

As the number of available web services increases, the development of web applications that integrate existing web services becomes more and more popular. This class of web applications can be seen as the composition of web services around a user interface flow. In this paper, the application of model-driven techniques for the development of such user-centric web applications is presented. An approach for the modeling of the application using UML class and state transition diagrams and the transformation to appropriate platform specific code is presented. The service design is based on the introduced UML profiles, whereas on code level frameworks implementing the Model-View- Controller architectural pattern are targeted. © 2008 ACM.

Mobile and wireless technology has revolutionized people’s lives by enabling data delivery anytime, anywhere, liberating the users from the restrictions of wired networks. In addition broadband communications permit high speed data connections. Since multimedia content delivered on-line requires reasonably high data rates and today’s wireless networks (3G, Wi-Fi, WiMAX etc) can support the quality requirements of media streaming delivery, while mobile devices handheld or not (Pocket PC, smart phones, laptop pc etc) are able to accommodate a variety of content formats, content delivery has become an indisputable trend. This paper presents such a content delivery network, the ENAMORADO architecture, which is the outcome of the work carried out in the IST project ENAMORADO (Enabling Nomadic Agents in a Multimedia Oriented Architecture of Distributed Objects). The ENAMORADO architecture covers the full content delivery chain from the media producers to the end users incorporating the content production, annotation, aggregation, adaptation and delivery. The paper describes the reference architecture of the infrastructure as well as the testbed used in the components integration and validation process. In addition further system evaluation results are presented.

Service oriented architectures (SOAs) are constantly gaining ground for the provision of business to business as well as user-centric services, mainly in the form of Web services technology. SOAs enable service providers to design and deploy new,composite service offerings out of existing component services. In order to match end-user expectations with respect to personalization and ease of use, these services should be designed in a manner that allows them to exhibit a certain level of context-awareness which is a basic element towards a richer end-user experience. However, in the majority of such services, context-handling is still tightly coupled with the core functionality of the service, resulting in a design which is difficult to implement and maintain. The paper proposes the decoupling of core service logic from context-related functionality by adopting a model-driven approach based on a modified version of the ContextUML metamodel. Core service logic and context handling are treated as separate concerns at the modeling level as well as in the resulting source code where aspect oriented programming (AOP) encapsulates context-dependent behavior in discrete code modules. The design of a restaurant finder service is used to portray the modified ContextUML metamodel and the service modeling process which is covered in full. Respective code snippets belonging to the executable version of the service (part of work in progress) are also provided, illustrating the transition from model to code and the resulting separation of concerns.

As technology develops, people are using an ever broader and heterogeneous range of ICT devices and network-based services. The result is an enormous burden of complexity on the shoulders of users, service providers and network operators. The goal of the Simplicity project, supported by the European Union, is to reduce this complexity by: (i) providing automatic customization of user access to services and the network; (ii) automatically adapting services to terminal characteristics and user preferences; (iii) orchestrating network capabilities. The Simplicity approach is based on a personalization device, the so-called Simplicity device, which, together with a brokerage framework, offers transparent service configuration and runtime adaptation, according to user preferences and computing/networking context conditions. This paper presents the Simplicity project, briefly discusses its architecture and introduces the Simplicity demonstrator: a proof of concept implementation used to verify our approach, through diverse usage scenarios. In addition, we introduce the main aspects of a follow-up project of Simplicity, named SMS.

Location-based services (LBS) constitute one of the most attractive services' categories for cellular networks. 3GPP defines the "Le" interface for external LBS provision and access to the core network of mobile operators. Multiple proprietary and commercial protocols and APIs can be used to implement this interface. The paper examines the realization of "Le" interface according to the proposed 3GPP standards, namely the mobile location protocol (MLP) over HTTP and the mobility API of OSA/Parlay using middleware technologies. The performance of both approaches is evaluated. Furthermore, with respect to the mobility API of OSA/Parlay, three implementations, based on respective middleware technologies (CORBA, RMI and Web Services over SOAP), are examined, for evaluating the performance of each OSA/Parlay gateway. The results of the experiments provide useful performance indicators concerning the efficiency of the internal architecture of each implementation as well as the anticipated speed of the user-service interaction.