The term 'Digital Economy' was coined for the first time by Don Tapscott in 1995 in his best-seller The Digital Economy: Promise and Peril in the Age of Networked Intelligence. When he wrote the book 20 years ago, he announced how he thought the Internet would fully transform the nature of business and government. We have now extended the concept, illustrating how digital technologies are rapidly transforming business practices, the economy and societies. Technology, and its impact on business strategy and society, continues to rise in importance. The Digital Economy, sometimes also called “Digital Business” has become a philosophy for many top executive teams as they seek competitive advantages in a world of fast moving technological change. When we talk about digital technologies, we are not only talking about the internet, nor only ICT (Information and Communications Technology), but other concepts such as mobile, telecommunications or content. The digital economy is by no means an exclusively economic concept. Therefore, it might be more appropriate to speak of digital society or digital technology. What matters is that digital is a transverse concept that affects individuals, businesses and public administrations.

People are progressively entering the digital world. In our daily life we are in direct contact with digital devices such as cars, electrical appliances etc. People increasingly communicate digitally; through mobile devices, internet, and social networks. In addition, our leisure, education and health are largely being integrated into a digital environment.

Likewise, organizations are progressively incorporating digital technology in their production and distribution processes, conducting research and also in the process of decision making. In this sense the emergence of Big Data has been one factor that has accelerated an already observed trend.

Public administrations and political institutions are incorporating digital into both their internal procedures and in their relationships with citizens. An example is the role played by Big Data in the two elections won by Obama. Another example may be the way the ISIS terrorist group uses social networking to publicize their activities and secure funding.

But digital technology and information are not only affecting the daily behavior of individuals, businesses and public administrations. They are also playing a very prominent role in the knowledge of the fundamental laws of nature. In this sense we can highlight the contribution of digital technology in the computer modeling of fundamental elements of life, and consequently in the creation of artificial life. Likewise, you may also note the role in deepening the knowledge of the universe.

Bearing in mind that Digital Economy is becoming more relevant from the economic perspective, we decided to star this issue with something unusual in this magazine: a paper that discusses the economy. It’s interesting from our point of view, as it underscores the fact that digital technologies, which of course include Artificial Intelligence and Interactive Multimedia, are not only relevant from the technical point of view, but from the business and society perspective as well.

The research works presented in this issue are based on various topics of interest, among which are included:  bayesian networks, evolutionary algorithms, virtual reality, web advertising, 3D technologies, traffic expression, Smart Cities, computational sustainability, computer vision, image recognition, deep neural networks, graphical models, mobile devices, human/complex system interactions, multi-agent systems, physics inspired behaviours, etc.

The International Journal of Interactive Multimedia and Artificial Intelligence provides an interdisciplinary forum in which scientists and professionals can share their research results and report new advances on Artificial Intelligence and Interactive Multimedia techniques.

This special issue, Special Issue on Multisensor user tracking and analytics to improve education and other application fields, concentrates on the practical and experimental use of data mining and analytics techniques, specially focusing on the educational area. The selected papers deal with the most relevant issues in the field, such as the integration of data from different sources, the identification of data suitable for the problem analysis, and the validation of the analytics techniques as support in the decision making process. The application fields of the analytics techniques presented in this paper have a clear focus on the educational area (where Learning Analytics has emerged as a buzzword in the recent years) but not restricted to it. The result is a collection of use cases, experimental validations and analytics systems with a clear contribution to the state of the art.

The International Journal of Interactive Multimedia and Artificial Intelligence provides an interdisciplinary forum in which scientists and professionals can share their research results and report new advances on Artificial Intelligence and Interactive Multimedia techniques.

The research works presented in this issue are based on various topics of interest, among which are included:  3D image reconstruction, Persian texts, usability evaluation methods, user experience, oriented matroids, flexible job-shop scheduling, business and social behavior, mobile computing and mobile devices, intelligent tutoring systems and geography optimization.

Pacheco et al. present a novel hybrid methodology, composed by 10 phases that combine active and passive methods, using images and a laser in order to supplement the missing information and obtain better results in the 3D object reconstruction. The proposed methodology proved its efficiency in two complex topological complex objects.

Noferesti, S. and Shamsfard M., write about Persian Texts and the Ezafe construction. They introduce a framework for combining genetic algorithms with rule-based models. This framework was used for recognizing the position of Ezafe constructions in Persian written texts. At the first stage, the rule-based model was applied to tag some tokens of an input sentence. Then, in the second stage, the search capabilities of the genetic algorithm were used to assign the Ezafe tag to untagged tokens using the previously captured training information. The proposed framework was evaluated on Peykareh corpus and it achieved 95.26 percent accuracy. Test results show that this proposed approach outperformed other approaches for recognizing the position of Ezafe constructions.

Schön, E.M. et al. describe a procedure to analyze and optimize scientific Internet information services that can be accomplished with relatively low effort. It consists of a combination of methods that already have been successfully applied to practice: Human beings, usability inspections, Online Questionnaire, Kano model and Web Analytics [3].

José Antonio Valero Medina and Ivan Lizarazo Salcedo describe the implementation of a prototype REST service for triangulation of point sets collected by mobile GPS receivers. The first objective of their work is to test functionalities of an application, which exploits mobile devices’ capabilities to get data associated with their spatial location.  A triangulation of a set of points provides a mechanism through which it is possible to produce an accurate representation of spatial data. Such triangulation may be used for representing surfaces by Triangulated Irregular Networks (TINs), and for decomposing complex two-dimensional spatial objects into simpler geometries. The second objective is to promote the use of oriented matroids for finding alternative solutions to spatial data processing and analysis tasks. This study focused on the particular case of the calculation of triangulations based on oriented matroids. The prototype described used a wrapper to integrate and expose several tools previously implemented in C++.

Celia Gutiérrez proposes a work based on an algorithm where each objective (resource allocation, start-time assignment) is solved by a genetic algorithm (GA) that optimizes a particular fitness function, and enhances the results by the execution of a set of heuristics that evaluate and repair each scheduling constraint on each operation. The flexible Job-shop Scheduling Problem (fJSP) considers the execution of jobs by a set of candidate resources while satisfying time and technological constraints. The aim of this work is to analyze the impact of some algorithmic features of the overlap constraint heuristics, in order to achieve the objectives at a highest degree. To demonstrate the efficiency of this approach, experimentation has been performed and compared with similar cases, tuning the GA parameters correctly.

Zouhair et al. present a work in the field of Intelligent Tutoring System (ITS), in fact, there is still the problem of knowing how to ensure an individualized and continuous learners follow-up during learning process, indeed among the numerous methods proposed, very few systems concentrate on a real time learners follow-up. This research develops the design and implementation of a Multi-Agents System Based on Dynamic Case Based Reasoning which can initiate learning and provide an individualized follow-up of learner. This approach involves the use of Dynamic Case Based Reasoning to retrieve the past experiences that are similar to the learner’s traces (traces in progress), and the use of Multi-Agents System. Through monitoring, comparing and analyzing learner traces, the system keeps a constant intelligent watch on the platform, and therefore, it detects the difficulties hindering progress and  avoids possible dropping out. The system can support any learning subject. To help and guide the learner, the system is equipped with combined virtual and human tutor [6].

Sati, M. et al. outline a solution about a fault-tolerant mobile computing model based on scalable replica. The most frequent challenge faced by mobile user is stay connected with online data, while disconnected or poorly connected store the replica of critical data. Nomadic users require replication to store copies of critical data on their mobile machines. Existing replication services do not provide all classes of mobile users with the capabilities they require, which includes: the ability for direct synchronization between any two replicas, support for large numbers of replicas, and detailed control over what files reside on their local (mobile) replica. Existing peer-to-peer solutions would enable direct communication, but suffers from dramatic scaling problems in the number of replicas, limiting the number of overall users and impacting performance. Roam is a replication system designed to satisfy the requirements of the mobile user. Roam is based on the Ward Model, replication architecture for mobile environments. Using the Ward Model and new distributed algorithms, Roam provides a scalable replication solution for the mobile user. They describe the motivation, design, and implementation of Roam and report its performance. Replication is extremely important in mobile environments because nomadic users require local copies of important data.

Bhaskar, V.S. et al., describe the work to elaborate swarm intelligence for business intelligence decision making and the business rules management improvement. Their paper introduces the decision making model which is based on the application of Artificial Neural Networks (ANNs) and Particle Swarm Optimization (PSO) algorithm. Essentially the business spatial data illustrate the group behaviors. The swarm optimization, which is highly influenced by the behavior of creature, performs in group. The Spatial data is defined as data that is represented by 2D or 3D images. SQL Server supports only 2D images till now. As they know that location is an essential part of any organizational data as well as business data: enterprises maintain customer address lists, own property, ship goods from and to warehouses, manage transport flows among their workforce, and perform many other activities. By means to say a lot of spatial data is used and processed by enterprises, organizations and other bodies in order to make the things more visible and self-descriptive. From the experiments, they found that PSO is can facilitate the intelligence in social and business behaviour.

Dixit, P. et al. write about the Internet security. This topic deals with the information secure and the integrity of the data. Sending messages over the Internet secretly is one of the major tasks as it is widely used for passing the message. In order to achieve security there must be some mechanism to protect the data against unauthorized access. A lossless data hiding scheme is proposed in this paper which has a higher embedding capacity than other schemes. Unlike other schemes that are used for embedding fixed amount of data, the proposed data hiding method is block based approach and it uses a variable data embedding in different blocks which reduces the chances of distortion and increases the hiding capacity of the image. When the data is recovered the original image can be restored without any distortion. The experimental results indicate that the proposed solution can significantly support the data hiding problem. We achieved good Peak signal-to-noise ratio (PSNR) while hiding large amount of data into smoother regions.

The science of happiness is trans-disciplinary. Happiness is an experience human beings have and, in consequence, its understanding calls for knowledge from all disciplines which, in one way or the other, deal with all facets of human lives. Various disciplines have contributed to the development of the science of happiness; among them: Psychology, Sociology, Economics, Psychiatry and Neuroscience. Because happiness research deals with human being of flesh and blood, it requires high-level techniques to dealing with large information sets in order to extract that information which is relevant. In the study of happiness there are many observations –as many as persons in the world-, there are many variables, and there are many interrelations and synergies to take account of. In consequence, happiness research benefits from sophisticated models that allow for a better understanding of people’s happiness; without losing contact with what real human beings experience, it is important to use techniques that allow researchers to process all the information reaching for valuable conclusions. It is with this purpose that Computer Science has joined the other disciplines providing its calculation powerful tools to advance the study of happiness. It is therefore appropriate that The International Journal of Interactive Multimedia and Artificial Intelligence has decided to launch a special issue on happiness showing some of the potential contributions the discipline can make to happiness research.

The research works presented in this issue cover various topics of interest, all related to potential contributions from Computer Science to the understanding of happiness and subjective well-being. 

The research works presented in this issue are based on various topics of interest, among which are included:  Mobile services, mpeg, agent-based Simulation, complexity, management accounting systems, animal-drawn vehicles, traffic and transport, possibility theory, precautionary saving, MAS, ambient intelligence, gamification, sustainable environments, disaster recovery, DSS, constraint programming and ICT.

López et al. presents the progress and final state of CAIN-21, an extensible and metadata driven multimedia adaptation in the MPEG-21 framework. CAIN-21 facilitates the integration of pluggable multimedia adaptation tools. To drive the adaptation, it uses the description tools and implied ontology established by MPEG-21. The paper not only describes the evolution and latest version of CAIN-21, but also identifies limitations and ambiguities in the description capabilities of MPEG-21.

Friederike Wall investigates the effectiveness of reducing errors in management accounting systems with respect to organizational performance. In particular, different basic design options of management accounting systems of how to improve the information base by measurements of actual values are analyzed in different organizational contexts. The results provide broad, but no universal support for conventional wisdom that lower inaccuracies of accounting information lead to more effective adaptation processes. Furthermore, results indicate that the effectiveness of improving the management accounting system subtly interferes with the complexity of the interactions within the organization and the coordination mode applied.

Sánchez-Aparicio et al. analyzes the structure of the data collected in the population dependent or receives its revenues in the use of animal-drawn vehicle, to extract an economic model for the development of this activity introducing formal parameters, as well as replacement of the vehicle analyzes the development of this activity in this population.

Ana María Lucia Casademunt and Irina Georgescu study the optimal saving problem in the framework of possibility theory. The notion of possibilistic precautionary saving is introduced as a measure of the way the presence of possibilistic risk (represented by a fuzzy number) influences a consumer in establishing the level of optimal saving. The notion of prudence of an agent in the face of possibilistic risk is defined and the equivalence between the prudence condition and a positive possibilistic precautionary saving is proved. Some relations between possibilistic risk aversion, prudence and possibilistic precautionary saving were established.

Celia Gutiérrez proposes a framework that incorporates robust analysis tools using IDKAnalysis2.0 to evaluate bullying effect in communications. The work is based on ICARO-T. This platform follows the Adaptive Multi-agent Systems paradigm. Experimentation with ICARO-T includes two deployments: the equitative and the authoritative. Results confirm the usefulness of the analysis tools when exporting to Cooperative Multi-agent Systems that use different configurations. Besides, ICARO-T is provided with new functionality by a set of tools for communication analysis.

Silva et al. presents an approach which uses information from different environments, ranking them according to their sustainability assessment. Recommendations are then computed using similarity and clustering functions ranking users and environments, updating their previous records and launching new recommendations in the process. Gamification concepts are used in order to keep users motivation and engage them actively to produce better results in terms of sustainabilit.

Caianiello et al. outline a solution to the problem of intelligent control of energy consumption of a smart building system by a prosumer planning agent that acts on the base of the knowledge of the system state and of a prediction of future states. Predictions are obtained by using a synthetic model of the system as obtained with a machine learning approach. They present case studies simulations implementing different instantiations of agents that control an air conditioner according to temperature set points dynamically chosen by the user. The agents are able of energy saving while trying to keep indoor temperature within a given comfort interval.

Amadini et al., propose an approach that could be used as a decision support tool for a post-disaster response that allows the assignment of victims to hospitals and organizes their transportation via emergency vehicles. By exploiting the synergy between Mixed Integer Programming and Constraint Programming techniques, we are able to compute the routing of the vehicles so as to rescue much more victims than both heuristic based and complete approaches in a very reasonable time.

Juan Carlos Piedra Calderón and  J. Javier Rainer explain the big influence of Information and Communication Technologies (ICT), especially in area of construction of Technological Societies. There are many changes that are visible in the way of relating to people in different environments. These changes have the possibility to expand the frontiers of knowledge through sharing and cooperation. That has meaning the inherently creation of a new form of Collaborative Knowledge. The potential of this Collaborative Knowledge has been given through ICT in combination with Artificial Intelligence processes, from where is obtained a Collective Knowledge. When this kind of knowledge is shared, it gives the place to the Global Collective Intelligence.

Guedes et al., proposes the definition of a system to negotiate products in an e-commerce scenario. This negotiation system is defined as PLANE – Platform to Assist Negotiation – and it is carried in a semi-automatic way, using multi-attributes functions, based on attributes of the negotiated content. It also presents an architecture to interconnect the participant through an inter-network in the television broadcasters context. Results demonstrated the success of the system in approximate the negotiator after some few interactions, reducing time and cost.

The International Journal of Interactive Multimedia and Artificial Intelligence provides an interdisciplinary forum in which scientists and professionals can share their research results and report new advances on Artificial Intelligence and Interactive Multimedia techniques.

The research works presented in this issue are based on various topics of interest, among wich are included:  AI for Software Engineering, Education, Computer Vision, Augmented Reality, Natural Language Understanding, Data Mining, Knowledge-Based/Expert Systems, Image Processing, Location systems, Internet of Things, Multiobjective Evolutionary Algorithms and Software architectures.

Barahona et al. presents an architecture and implementation for mobile application that use Augmented Reality techniques to get information while interacting with real objects in the physhical world. The presented application allows the creation of new context aware content for collaborative applications in different fields of knowledge.

Solís-Martínez et al. defines a methodology that allows the reduction of the complexity on the common processing modeling notations. The proposed level oriented bussines process methodology is intended for being used by domain experts that will model the domain business processes outside the technical details.

Cueva-Fernandez et al. proposes a framework which significantly simplifies the development process of the smartphone applications that require a high degree of interoperability between device sensors. The proposed framework is illustrated with a fuctional prototype that demonstrates the feasibility of creating multidisciplinary applications with several different approaches.

Nuñez-Valdez et al. have developed a graphical tool based on domain-specific languages that simplifies the development of 2D games for mobile devices. The proposed tool allows modeling games abstracting from technical details and implementations. The modeled games can be exported to popular mobile platforms, thus allowing to develop games quickly and saving development costs.

Puértolas et al. present a new location indoor system that combines the use of Smartphones with location tags. The location tags are based in QR codes and NFC tags and serve for determine the user’s position and orientation. The proposed system can use the information to calculate the optimal toure to the destionation.

Rodriguez et al. presents a revision and an analysis of the Open Data initiative situation in Spain. The analysis looks at origins and concepts, the legal framework, current Initiatives and challenges that must be addressed for the effective reuse of public information industry.

Fuente et al. proposes a novel approach to empower domain experts in developing adaptability solutions by using automated sets of production rules in a friendly way. This approach is focused on the expert’s domain knowledge, allowing them to evolve and adapt the software focusing on business logic and not on technical aspects. This approach is particularly useful for very dynamic or changing sectors with rules closely linked to the domain.

Sandra Garcia presents a resume of her doctoral thesis called: “Application of Multiobjective Techniques for Robust Portfolio Optimization”. Supervised by Dr. David Quintana Montero and Dr. Inés M. Galván León and defended at Carlos III of Madrid (Spain).

Dubey et al. presents a novel algorithm, specially designed to detect defects in fruits. The manual identification of fruits defects is a very slow and expensive process. This research work proposes a segmentation of fruits based on color features with K-means clustering unsupervised algorithm. The authors apply their proposal to a real case in identifying defects in apples; this real case is useful to validate the effectiveness and quality of the proposed approach.

Gil et al. analyzed and reviewed several of the technologies of knowledge exchange and dissemination, putting particular emphasis on technologies that affect the field of education. This article focuses in the question emerging from the clash of the rights to education in a wide sense and the rights derived from authorship.

Daniel Burgos presents an innovative adaptation of eLearning model which supports user behaviour, user interaction, and personalised counselling by a tutor to improve the usual model. Also he shows the built eLearning module that implements this conceptual model in a real application case.

This regular issue includes extended versions of selected papers from The 6th International Conference on Multimedia and Ubiquitous Engineering, held in Leganes - Madrid, Spain, 2012. The issue includes, thus, nine selected papers, describing innovative research work, on several areas of Artificial Intelligence and Interactive Multimedia including, among others: Mobile and Cloud Computing, Semantic Brokering, Metaheuristic Optimization Algorithms, Video Services, Dynamic Conceptual Data, Accessing Wireless Sensor, Models of E-Commerce and Service Orchestration.

We would like to thank all the contributing authors, as well as all members of International Conference on Multimedia and Ubiquitous Engineering, for their hard and valuable work that assured the high scientific standard of the conference and enabled us to edit this issue. Finally, the Guest Editors would also like to thank the Editors-in-Chief of International Journal of Interactive Multimedia and Artificial Intelligence for the publication of this issue.

Jeús Carretero Pérez (Carlos III University), José Daniel García Sánchez (Carlos III University)