Abstract
It is widely recognized that legislation is of critical importance for the proper functioning of economies and societies. However, the increasing complexity of the problems and challenges faced by modern economies and societies have resulted in the development of extensive, highly complex, and continuously evolving legislations. This makes it difficult for firms and administrations, as well as individual lawyers and public servants, to know the current applicable legislation on a particular topic of interest, as well as its evolution over time. This difficulty increases further due to the internationalization–globalization of economic activity, as well as the development of supranational organizations (such as the European Union (EU)), which make it necessary to continuously monitor legislations of several countries on various topics of interest. Existing national legal information platforms cannot satisfy the above highly complex requirements. This paper contributes to filling this gap, initially by describing the architecture and the capabilities/ functionalities of an advanced “international” legal information platform, which has been developed as part of the European research program “ManyLaws,” based on requirements collected through interviews with lawyers and public servants; it enables the advanced search and retrieval of relevant legal documents on a particular topic of interest from within the legislative corpuses of many different countries, as well as EU legislation, using existing sources of open legal information, and also the automated comparative analysis of them and identification of various types of relations among them. The evaluation of this advanced legal information platform, using an extension of the Technology Acceptance Model (TAM), provides evidence of the usefulness and the ease of use of its novel functionalities, as well as their positive contribution to the productivity of both national-level legal work and international level legal work, especially within the EU. The proposed advanced legal information platform can be quite useful for firms and administrations, as well as individual lawyers and public servants, active in the modern globalized economic context.

Abstract
Purpose – This study aims to underline the possible influence of the moderator, information systems (IS) infusion, on Open Government Data (OGD) adoption and usage. Design/methodology/approach – Using the partial least squares-structural equation modeling methodological approach, the adapted unified theory of acceptance and use of technology (UTAUT) model has been used for understanding the role of themoderating variable, namely, IS infusion. Findings – Findings show that the moderating impact of IS infusion is positively significant with respect to the performance expectancy–behavioral intention relationship thereby bolstering the impact on users’ perception of OGD vis-a-vis work/academics performance and negatively significant for social influence–behavioral intention, information quality–behavioral intention, thereby clinching the fact that with the increased engagement and involvement of OGD in the everyday life of the user, the role of significant others and information quality gets least significant. Originality/value – Extant OGD-focused research has underscored the impact of different variables as far as OGD adoption and usage is concerned; the present study seeks to add on to the extant literature by understanding the implications of IS infusion on the adapted UTAUT model constructs and behavioral intention relationships.

Abstract
One of the most promising developments comes with the use of innovative technologies and thus with the availability of novel services. The combination of text mining with legal elements may contribute to the development of many innovative legal IS. Moreover, in the case of public administrations and governments, the distribution, availability, and access towards legal information are essential and urgent. On the other hand, legal data and law texts are a potential open Government data category in order for innovation to be achieved, regarding the development of new, better, and more cost-effective services for citizens. Those data need to be available 24/7 basis and compliant towards a standard. Yet, there exist some severe issues at the moment regarding this access. This, in turn, makes the use of automated crawling and analysis more than difficult. This paper describes the "Peri Nomou" system: an innovative legal information system for Greek laws utilising text mining techniques to indexing legal documents, identifying correlations and dividing legal documents into their articles.

Abstract
Open government data (OGD) initiatives have proliferated over the last years in many countries all over the world as the result of a long-standing movement towards the ‘open government’ paradigm. These initiatives have been launched and maintained by a variety of government organizations with different strategies and technical capacities, and under different social, political and legal conditions. As a result, the OGD sources (defined as various types of portals enabling access to government datasets by the public through the Internet and providing various capabilities/functionalities in this direction) developed through these initiatives demonstrate a great diversity in both content, functionality and technology. However, limited research has been conducted on these OGD sources for understanding better their main characteristics from various perspectives, and identifying their strengths and weaknesses. This paper contributes to filling this research gap, by presenting an analysis of the thematic, functional, semantic and technological characteristics of OGD sources in Greece. Sixty OGD sources have analysed from these perspectives and statistical analysis of relevant characteristics have been performed. Interesting conclusions have been drawn from this analysis, and based on them recommendations have been formulated for government policy makers, in order to enhance OGD provision in Greece, and increase the social and economic value that can be generated from them.

Abstract
The opening of government data, in order to have both social and economic value generated from them, has attracted the attention and interest of both researchers and practitioners from various disciplines, such as information systems, management sciences, political and social sciences and law. Despite the rapid growth of this multidisciplinary research domain, which has led to the emergence and continuous evolution of technologies and management approaches for open government data (OGD), a detailed analysis of the specific areas and topics of this research is still missing. In this paper, a detailed taxonomy of research areas and corresponding research topics of the OGD domain is presented: it includes 4 main research areas (ODG management & policies, infrastructures, interoperability and usage & value), which are further analysed into 35 research topics. An important advantage of this taxonomy, beyond its high level of detail, is that it has been developed through extraction and combination of relevant knowledge from three different kinds of sources: important relevant government policy documents, research literature and experts. For each of these 35 research topics we identified, its research literature has been summarized and main research objectives and directions have been highlighted. Based on the above taxonomy, an extension of the existing in the literature OGD lifecycle has been proposed; also, under-researched topics that require further research have been identified. Our OGD research taxonomy extends and elaborates previous research taxonomies for the ‘ICT-enabled Governance’ and ‘Policy Making 2.0’ domains, which have been developed in the European projects CROSSROAD and CROSSOVER.

Abstract
Government agencies all over the world are making big investments for developing information systems that open important data they possess to the society, in order to be used for scientific, commercial and political purposes. It is important to understand what value they create and how, and at the same time – since this is a relatively new type of information systems (IS) – to identify the main improvements they require. This paper contributes in this direction by presenting a methodology for determining the value generation mechanism of open government data (OGD) systems and also priorities for their improvement. It is based on the estimation of a ‗value model‘ of the OGD system under evaluation from users‘ ratings, which consists of several value dimensions and their corresponding value measures, organized in three ‗value layers‘, and also the relations among them. The proposed methodology has been successfully applied to an OGD system developed as part of the European project ENGAGE (‗An Infrastructure for Open, Linked Governmental Data Provision towards Research Communities and Citizens‘), and provided interesting insights and improvement priorities. This first application provides evidence that our methodology can be a useful decision support tool for important ODG systems investment, management and improvement decisions.

Abstract
One essential characteristic of open data ecosystems is their development through feedback loops, discussions and dynamic data suppliers - user interactions. These user-centric features communicate the users’ needs to the open data community, as well to the public sector organizations responsible for data publication. Addressing these needs by the corresponding public sector organizations, or even by utilising the power of the community as ENGAGE supports, can significantly promote and accelerate innovation. However, such elements appear barely to be part of existing open data practices in the public sector. A survey we conducted has shown that professional open data users find the feedback and discussion on open data infrastructures from their users to their providers as highly useful and important, but they state that they do not know at least one open data infrastructure that provides various types of discussion, and feedback mechanisms. In this paper we describe and discuss an open data platform, which contributes to filling this gap and also present a usage scenario of it, explaining the sequence of using its functionality. The discussed open data infrastructure combines functionalities that aim to close the feedback loop and to return information to public authorities that can be useful for better government data opening and publication, as well as establishing communication channels between all stakeholders. This may effectively lead to the stimulation and facilitation of value generation from open data, as such functionality positions the user at the centre of the open data publication process.

Abstract
As a novel Artificial Intelligence (AI) application, ChatGPT holds pertinence not only for the academic, medicine, law, computing or other sectors, but also for the public sector-case in point being the Open Government Data (OGD) initiative. However, though there has been some limited (as this topic is quite new) research concerning the capabilities ChatGPT in these sectors, there has been no research about the capabilities it can provide to government concerning its wide range of functions and activities. This paper contributes to filling this gap by investigating the capabilities that the ChatGPT can provide concerning one of most recently ini-tiated and novel, and at the same time most promising, activities of government that aims to fuel the emerging data economy and society: the opening of large amounts of government data; furthermore, we investigate the public values that can be promoted through the use of ChatGPT in the area of OGD by both the da-ta publishers as well as their users. At the same time, we investigate the issues that the use of ChatGPT in the area of OGD can pose, which can reduce the ca-pabilities identified as aforesaid as well as the benefits and public values that can be generated from them. For these purposes interviews with 12 experts have been conducted and their responses have been analyzed. Finally, based on our findings we have developed a research agenda concerning the exploitation of ChatGPT application in the OGD domain.

Abstract
Extant research on Open Government Data (OGD) has remained confined to the grappling of issues linked with its conceptual, theoretical and empirical dimensions, however focusing on the supply of OGD physical capital (ODG portals, datasets, etc.), and to a lesser degree on the demand for it (e.g., needs of potential users), but not dealing with relevant OGD human capital (human knowledge and skills concerning OGD). Furthermore, research on meta-analysis or literature reviews has not expanded its scope to unravel the formation of OGD human capital, and especially how the OGD theme is being showcased across universities’ curriculum. The present research aims to contribute to filling this research gap, through an analysis of the OGD-related programs and courses offered at the graduate and post-graduate levels across the top-notch universities identified as per the indicators of the QS World University rankings, 2023. Our theoretical foundation is the widely recognized ‘Human Capital Theory’ from the economic science, which gives prominence to the importance of the human capital (human knowledge and skills) as an important complement of the classical physical capital (e.g., production equipment, ICT capital, etc.). Our findings indicate that there are only small number of courses concerning OGD in these top-notch universities; furthermore, a very small share of them have OGD an main topic, while most of them include only a part concerning OGD. Most of them focus on the exploitation of OGD of a specific thematic domain (mainly urban studies and health), and only a few deal with OGD in general. Furthermore, there is a prevalence of postgraduate courses, offered as part of MSC programs, followed by undergraduate courses, offered as part of BSC study programs, and to a much lesser degree short courses. Also, with respect to the objective of these OGD-related programs and courses, most of them aim at the generation of scientific value from OGD, while a smaller number aim at the generation of social-political value, and only a much smaller number at the development of economic value. Therefore, it can be concluded that the formation of OGD human capital by the examined universities is limited.

Abstract
∗Legal information is of paramount importance for social, economic and political activities. Sophisticated legal information retrieval (LIR) systems are designed and built to facilitate user access to accurate and current legal information. The advent of new types of capabilities in the legal information systems domain has necessitated a closer look at the performance and usability of such advanced computer systems, and brought into sharp focus the requirement for an effective evaluation of the available functionalities and quality of the software. The purpose of this research paper is to develop a framework for the effective monitoring and evaluation of an advanced legal information system from differing salient perspectives, and to critically examine the basic set of attributes that characterize the important dimensions of platform functionality. Through the application of the developed evaluation model to a novel legal data platform, we propose both a rigorous validation of the framework itself, together with the identification of the strengths and shortcomings associated with the use of the system under consideration.

Abstract
Legal information is of paramount importance for social, economic and political activities. Sophisticated legal information retrieval (LIR) systems are designed and built to facilitate user access to accurate and current legal information. The advent of new types of capabilities in the legal information systems domain has necessitated a closer look at the performance and usability of such advanced computer systems, and brought into sharp focus the requirement for an effective evaluation of the available functionalities and quality of the software. The purpose of this research paper is to develop a framework for the effective monitoring and evaluation of an advanced legal information system from differing salient perspectives, and to critically examine the basic set of attributes that characterize the important dimensions of platform functionality. Through the application of the developed evaluation model to a novel legal data platform, we propose both a rigorous validation of the framework itself, together with the identification of the strengths and shortcomings associated with the use of the system under consideration.

Abstract
Most of the research that has been conducted in the area of legal infor-matics concerns its ‘supply side’, dealing with the development of effective sys-tems for legal information provision. However, limited research has been con-ducted on the ‘demand side’ of legal information provision, though it is abso-lutely necessary to gain a good understanding of it, in order to design effective and useful systems for the provision of legal information; furthermore, this lim-ited research is dealing with the legal information needs of the lawyers, and ne-glects the ones of other important groups. This paper contributes to filling this research gap. It analyses legal information requirements of a highly important for the society group: the designers of public policies. Initially we investigate current legal information sources and systems used by public policy makers, as well as their relevant search practices. Then we investigate their business needs for ad-ditional capabilities/functionalities for a better support of their policymaking ac-tivities using advanced legal analytics tools and services. Finally, we discuss the information, processing and technical requirements for the development of a le-gal information system providing the above advanced functionalities and ser-vices. For the above purposes, we have collected data through semi-structured interviews form 13 Greek and 7 Austrian public administrators dealing with the design of public policies, which lead to interesting and useful insights, as well as a novel set of additional advanced capabilities and functionalities that can give rise to a new generation of legal informatics.

Abstract
Most of smart city research focuses on the ‘supply-side’, and only limited research has been conducted about the ‘demand-side’ of smart cities: the smart city actions that are perceived by citizens as having higher usefulness, value and therefore priority; also limited research has been conducted for the comparison between the supply-side and the demand-side of smart cities. This paper contributes to filling these important research gaps. It investigates and compares smart city actions’ priorities of the municipalities with the ones of the citizens, in order to identify points of convergence as well as of divergence. A novel methodology has been constructed for this purpose, which includes as a first step the development of a detailed taxonomy of possible smart city actions, based on previous relevant literature. This taxonomy is then used for collecting assessment data from municipalities as well as from citizens concerning these possible smart city actions. Furthermore, our methodology includes three layers of processing of the above assessment data, which identify: a) the priorities of these two important stakeholders concerning smart city actions; and b) points of convergence as well as points of divergence between them. This methodology has been applied in the context of the Greek local government. Assessment data concerning the importance of the smart city actions of the above taxonomy were collected from 144 Greek municipalities and 500 citizens; their processing has revealed an important divergence between these two important smart city stakeholders.

Abstract
Digital Governance (initially ‘Electronic Government’, and later ‘Electronic Governance’ incorporating also ICT-based innovations and transformation) has emerged as a research and practice domain aiming at the exploitation of information and communication technologies (ICT) in government, in order to support, transform and enhance its activities, both the internal ones, as well as the ‘extrovert’ ones concerning communication with the external environment (dialogue and consultation with citizens and firms, and also transaction with them), in order to increase their effectiveness and efficiency. During the last decades, Digital Governance has been recognized as a well-established domain with a highly ambitious objective, which is quite beneficial for the society and the economy: to study and advance the exploitation of ICT for addressing problems and needs of public sector organizations, and develop novel methods and frameworks for enhancing their internal efficiency, service quality and policy-making effectiveness through the use of ICT. Though substantial progress has been made through government funded as well private sector research in a number of areas of it, yet the lack of a science base of the Digital Governance domain seems to hinder unlocking the real transformative value of ICT in the public sector, as well as the full contribution and creativity potential of all its stakeholders, from researchers to industry and SMEs. Such a scientific background would enable a better documentation, organization, structuring of the existing knowledge in this area, as well as its dissemination through training, and also provide systematic directions for high priority future research, in order to develop a portfolio of systematic solutions to specific problems concerning the exploitation of ICT in government organizations (methods for assessment and identification of problems, as well as methods for providing solutions, which can be applied (possibly with some adaptations) in a wide range of organizational, cultural and legal contexts, as it happens in ‘mature’ sciences, such as the engineering ones).This paper provides some research directions concerning the development of the science base of the Digital Governance domain as well as its evolution, and proposes specific relevant research questions that have to be addressed.

Abstract
For long time research and practice in the area of Electronic Government (e-government) has been focusing on the use of information and communication technologies (ICT) for improving the efficiency government agencies’ internal operations, as well as transactions with citizens and firms. However, the increased needs and expectations of citizens, and the proliferation of ‘participatory democracy’ ideas, gave rise to a new generation of ICT exploitation by government for increasing and enhancing citizens’ participation. Furthermore, the increasing social problems and challenges that had to be addressed by government through appropriate public policies, such as the increasing inequalities and poverty, the aging society, the environmental degradation, and the rising number of ‘unpredictable’ events, such as the financial and economic crisis, give rise to the development of a new wave of egovernment focusing on policy analytics for supporting the design of effective responses - public policies for these challenges. Therefore, evolutions in the needs of modern societies, in combination with technological evolutions, give rise to evolutions in e-government, and the emergence of new generations of it. This paper aims at the identification and better understanding of the main characteristics of the different e-Government generations, using an analytical framework based on two rounds of literature review. The results of the study provide insights on the main features of the three main e-government generations, regarding their main goals, obstacles, key methods and tools, and reveal the new emerging generation of e-Government 3.0 and its basic characteristics. Furthermore, within the first and to some extent the second e-Government generation there have been substantial advancements, which have created distinct sub-generations of them, revealed and analysed through extensive relevant growth/maturity stages research.

Abstract
Big Data is, clearly, an integral part of modern information societies. A vast amount of data is, daily, produced and it is estimated that, for the years to come, this number will grow dramatically. In order for transforming this hidden provided information into a useful one, the use of advanced technologies, such as Machine Learning is deemed appropriate. Over the last years, Machine Learning has grown a great effort considering the given opportunities its usage provides. Furthermore, Machine Learning is a technology that can handle Big Data classification for statistical or even more complex purposes such as decision making. At the same time the new generation of government, Government 3.0, explores all the new opportunities to tackle any challenge faced by contemporary societies by utilizing new technologies for data driven decision making. Taking into account the opportunities Machine Learning can provide, more and more governments participate in the development of such applications in different governmental domains. But is the Machine Learning only beneficial for public sectors? Although there is a huge number of researches in the literature there is no a comprehensive study towards the analysis of this technology. Our research moves towards this question conducting a comprehensive analysis of the use of Machine Learning from Governments. Through the analysis all benefits and barriers are indicated from the public sectors' perspective pinpointing, also, a number of Machine Learning applications where governments are involved.

Abstract
Europe's vision is to establish a well-functioning Digital Single Market, where Europeans are able to move and trade among the EU member states. On the other hand the large amount of information about laws that apply in each EU country has posed significant barriers in this vision. Moreover only legal experts can follow the latest legislation in each country consuming a large amount of business resources in order to follow the current legislation. However, Mass customization tools can help to filter and thereby reduce the flood of legal information and make it easier to be followed from businesses and citizens without legal expertise. The proposed solution is a novel ICT architecture utilising and built upon text mining, advanced processing and semantic analysis of legal information towards the provision of a set of services for citizens, businesses, and administrations of the European Union. In order to provide the most appealing, comprehensive and added value services in the legal domain, this paper presents six use case scenarios based on the opinion of different target groups. Conducting interviews and focus groups, we were able to identify the novel functionalities and services of great importance for the users highlighting and addressing users' daily problems regarding legal information. Generally, interviews with the different target groups reveal that at this point, users prioritise their needs towards more basic services such as search functionalities and correlation with previous laws. Lawyers on the other hand as more competent target group asked for summarisation and reporting services. All target groups where eager on the implementation of this service which as it seems it will directly impact their everyday professional and personal use of legal information.

Abstract
Public administration and information technology university departments worldwide have responded to the explosion in e-Government by offering related programs or courses. In this study, the authors investigated education programs in e-Government by reviewing the curriculum and course descriptions of 70 programs that had web listings of their programs. Findings suggest that 64 institutions, from 32 countries worldwide, offer e-Government related programs. The programs are classified into four types based on their education level. Offered courses have been classified in 15 clusters. The majority of the proposed courses belong to the areas of Information Systems (20,7%), e-Governance (17,8%), Management (12,9%) and Public Administration (8,4%) clusters.

Abstract
Nowadays, Blockchain Technologies (BCT) could be characterized as one of the most promising trends. We are currently witnessing a plethora of implementations basically in the economic sector with the creation of cryptocurrencies. The majority of researchers and practitioners argues that many benefits could be derived from the use of this innovative technology with the most significant one being the improved sense of trust to BCT applications. At the same time governments pursue amplified trust from their citizens and BCT is gaining momentum since it addresses this of utmost importance problem based on its unique characteristics. More and more governments realize the advances of this technology and participate in pilot applications in different vertical governmental sectors. Even though there are several implementations in the Government sector, there is no comprehensive study towards the analysis of the major characteristics of these developments. This paper moves towards the fulfilment of this gap conducting a thorough analysis of e-Government pilot applications of BCT in a European level. Furthermore, this study discusses the key benefits and main barriers coming from the application of this technology in different domains with BCT experts.

Abstract
The development and success of the ‘business analytics’ in the private sector, in combination with the growing availability of large quantities of useful data in government agencies, gives rise to the emergence of the ‘policy analytics’ in the public sector. However, though some knowledge has already been developed in this area, extensive research is required in order to increase our knowledge base concerning the exploitation of these exponentially increasing quantities of data available in government, in combination with data from private sector firms as well, using advanced analytical techniques (from various areas, such as machine learning, sta-tistics, simulation, etc.), in order to provide substantial support for all stages of public policies in various important policy domains. This paper makes a contribution in this direction, by de-scribing a methodology for policy analytics in the economic policy domain, concerning a highly important problem: the economic crises, which repeatedly occur in market-based economies being an inevitable trait of them. Our methodology aims at the identification of firm’s character-istics that affect positively or negatively their sensitivity to the economic crisis, which enables a deeper understanding of the kinds of firms that exhibit higher sensitivity to economic crisis (i.e. have more negative consequences) and provides a basis for the design of public policies for supporting such firms. It exploits existing data from various public sources (e.g. Ministries of Finance, Statistical Authorities), in combination with data from private sources (e.g. business information firms, consulting firms), from which firm-level crisis sensitivity models are estimated. Furthermore, an application of the proposed methodology is presented, using data from Greek firms for the crisis period 2009 – 2014, which provides interesting insights.

Abstract
For long time research and practice in the area of Electronic Government has been focusing on the use of information and communication technologies (ICT) for improving the efficiency and effectiveness of the internal operations of government agencies, as well as for providing elec-tronic transaction services to citizens and firms. The increased needs and expectations of citi-zens, and the proliferation of ‘participatory democracy’ ideas, result in an increase of their di-rect participation in policy making processes, and the use of ICT seems to be an important fa-cilitator of this. At the same time the multiple social problems and challenges to be addressed through policy-making, such as the increasing inequalities and poverty, the aging society, the environmental degradation, and the rising number of ‘unpredictable’ events, such as the finan-cial and economic crises, necessitate the development of a new generation of eGovernment fo-cusing on the design of effective responses - public policies for these challenges. Therefore evo-lutions in the needs of modern societies, in combination with technological evolutions in the ICTs, give rise to evolutions in e-Government, and the emergence of new generations of it. This paper aims at the identification and better understanding of the main characteristics of the dif-ferent e-government generations, using an analytic framework based on two rounds of literature review. The results of the study provide insights on the main features of the three main e-Government generations, regarding their main goals, obstacles, key methods and tools, placing special emphasis on the new emerging generation of e-Government 3.0 and its basic character-istics.

Abstract
One of the most promising developments comes with the use of innovative technologies and thus with the availability of novel services. The combination of text mining with legal elements may contribute to the development of many innovative legal information systems. Moreover, in the case of public administrations and governments, the distribution, availability, and access to-wards legal information are essential and urgent. On the other hand, legal data and law texts are a potential open Government data category in order for innovation to be achieved, regarding the development of new, better, and more cost-effective services for citizens. Those data need to be available 24/7 basis and compliant towards a standard. Yet, there exist some severe issues at the moment regarding this access. This, in turn, makes the use of automated crawling and analysis more than difficult. This paper describes the “Peri Nomou” (about law) system: an innovative legal information system for Greek laws utilising text mining techniques to indexing legal documents, identifying correlations and dividing legal documents into their articles. The first version of the system has been evaluated by legal experts and the second version is developed based on the previous evaluation and presented in this paper. The results from the evaluation indicate the significance of the “Peri Nomou” system for the legal experts and allow us to promote the Peri Nomou system to other user groups, such as business, public administration.

Abstract
Government 3.0 is characterised by the utilisation of disruptive technologies in conjunction with already established ones towards data-intensive decision and policy making. One of the disruptive technologies that will affect in general e-government applications and services provision and will more specifically frame government 3.0, is BCT. Yet no systematic research is available which compares the benefits of BCT with the barriers to its adoption. This paper conducts a literature, research projects and applications review for the BCT within the respecting area of e-government. The inquiry follows a desk-based methodology for the identification of the primary references and research projects as well as a qualitative discussion with experts of the domain. This study identifies the major benefits and impediments for the application of this technology in the e-government domain. The findings show that a gap exists between the promised benefits and barriers and frame future research directions.

Abstract
Since its inception, open government data (OGD) as a free re-useable object has attracted the interest of researchers and practitioners, civil servants, citizens and businesses for different reasons in each target group. This study was designed to aggregate the research outcomes and developments through the recent years towards illustrating the evolutionary path of OGD portals, by presenting an analysis of their characteristics in terms of a maturity model. A four-step methodology has been followed in order to analyse the literature and construct the maturity model. The results point out the two greater dimensions of OGD portals, naming traditional and advanced evolving within three generations. The developed maturity model will guide policy makers by firstly identify the current level of their organisation and secondly design an efficient implementation to the required state.

Abstract
Open data portals have been a primary source for publishing datasets from various sectors of administration, all over the world. However, making open data available does not necessarily lead to better utilisation from citizens and businesses. Our paper presents a new framework and a prototype system for supporting open application development by citizen communities, through gathering and making available open data and open web services sources from governmental actors, combined with an application development environment, training material and application examples.

Abstract
Two important trends in government emerging in the recent years have been on one hand the exploitation of the Web 2.0 social media supporting a more extensive interaction and collaboration, and on the other hand the opening of government data to the citizens through the Internet in order to be used for scientific, commercial and political purposes. However, there has been limited attempt of integrating them. Using a design science approach a second generation of open government data (OGD) platforms is developed, which offer to the users both the „classical‟ first generation functionalities, and also a comprehensive set of additional Web 2.0 features. The latter enables social and collaboration, which enable users to generate value from ODG. In this way users become „prosumers‟, both producing and consumingdata. Capabilities forperforming various types of processing,information and knowledge exchange, and collaboration were found to be useful and valuable in a user test.

Abstract
Numerous open data infrastructures are currently under development aiming to stimulate the potential advantages of the publication and use of open government data. In particular the development of open data infrastructures in the form of marketplaces, where open data providers and open data users trade and share data and data services, can stimulate the realisation of these advantages. Yet, only little research has been conducted on the development directions of open data infastructures to realise such marketplaces. This study aims to identify elements for the development of future electronic open data marketplaces. This aim is attained by using a literature review and expert discussions, which resulted in the following elements: 1) bring stakeholders together, 2) provide rich metadata, 3) enable data quality assessment, 4) ensure trust, security and critical mass, 5) have an appropriate revenue model, 6) provide use cases, training and support, 7) provide technical support: open data tools, 8) provide a full API for machine-to-machine operation and 9) target multiple nationalities. The results of this study can be used to develop and improve open data marketplaces to stimulate the realisation of open data advantages.

Abstract
Recently, a second generation of advanced open government data (OGD) infrastructures has emerged, influenced by the principles of the Web 2.0 paradigm, and oriented towards the elimination of the clear distinction between providers and consumers of such data, and the support of data ‘pro-sumers’. This paper presents and validates a methodology for evaluating these advanced second generation of ODG infrastructures, which is based on the estimation of value models of them from users’ ratings. This value model includes assessments of the various types of value generated by such an infrastructure, and also of the relations among them as well. This enables a deeper understanding of the whole value generation mechanism and a rational definition of improvement priorities.The proposed methodology has been used for the evaluation of an advanced second generation ODG e-Infrastructure developed in the European project ENGAGE.

Abstract
Many government agencies worldwide have started making considerable investments for developing information systems that enable opening important data they possess to the society, in order to be used for scientific, commercial and political purposes. In order to rationalise and support future decisions concerning the development, upgrade, improvement and management of this new type of information systems it is important to understand better what value they create and how, and at the same time to identify the main improvements they require. This paper contributes in this direction presenting a methodology for determining the value generation mechanism of open government data (OGD) systems and also priorities for their improvement. It is based on the estimation of a ‘value model’ of the OGD system under evaluation from users’ ratings. It consists of several value dimensions and their corresponding value measures, organized in three ‘value layers’, and also the relations among them. These three value layers concern value related to the efficiency of the OGD (= quality of the various capabilities it provides to the users), its effectiveness (= degree of supporting users for achieving their objectives) and also users’ future behavior intentions respectively. The proposed methodology has been applied successfully to an advanced OGD system developed as part of the European project ENGAGE (‘An Infrastructure for Open, Linked Governmental Data Provision towards Research Communities and Citizens’), providing to interesting insights and improvement priorities. This first application provides evidence that our methodology can be a useful decision support tool for important ODG systems development, upgrade, improvement and management decisions.

Abstract
Considerable investments are made to develop numerous e-infrastructures for the reuse of open government data for scientific, commercial and political purposes. This necessitates a deeper understanding and assessment of the value these infrastructures generate. For this purpose, our paper presents a framework for evaluating open government data infrastructures, both ‘traditional’ ones following the web 1.0 paradigm and also advanced ones influenced by the web 2.0 paradigm. The evaluation framework is based on findings of previous research on the evaluation of public projects, information systems and e-services, and also on technology acceptance and IS success models. The proposed evaluation framework consists of an evaluation model with measurable evaluation dimensions and criteria, as well as a comprehensive evaluation procedure for using this evaluation model, which enables both higher level and detailed evaluation. It includes quantitative as well as qualitative methods in order to provide comprehensive and deep insights. Finally, we describe an application of the proposed framework (both the model and the procedure) for the evaluation of a European e-infrastructure for opening government data. This first application has provided some first evidence concerning the applicability and usefulness of the proposed evaluation framework, and at the same time useful directions and ideas for the improvement of the above-mentioned e-infrastructure.

Abstract
The trend of opening government data, in order to be used for scientific, commercial and political purposes, has resulted in the development of numerous e-infrastructures providing public sector information (PSI). The big investments that have been made in this direction necessitate a deeper understanding and assessment of the value they produce. This paper presents a methodology for evaluating PSI einfrastructures, which is based on the estimation of multiple value models corresponding to their main stakeholder groups: data users and data providers. Each value model consists of several value dimensions and their corresponding value measures, organized in three levels (associated with efficiency, effectiveness and future behaviour), and also the relations among them. The proposed methodology allows a comprehensive assessment of the various types of value generated by a PSI e-infrastructure for each stakeholder group, and also the interconnections among them. This enables a better understanding of the whole value generation mechanism and a rational definition of improvements priorities.