<p>We discuss the Normal inverse Gaussian (NIG) distribution in modeling volatility in the financial markets. Refining the work of Barndorff-Nielsen (1997) and Andersson (2001), we introduce a new parameterization of the NIG distribution to build the GARCH(p,q)-NIG model. This new parameterization allows the model to be a strong GARCH in the sense of Drost and Nijman (1993). It also allows us to standardized the observed returns to be i.i.d., so that we can use standard inference methods when we evaluate the fit of the model.</p><p>We use the realized volatility (RV), calculated from intraday data, to standardize the returns of the ECU/USD foreign exchange rate. We show that normality cannot be rejected for the RV-standardized returns, i.e., the Mixture-of-Distributions Hypothesis (MDH) of Clark (1973) holds. {We build a link between the conditional RV and the conditional variance. This link allows us to use the conditional RV as a proxy for the conditional variance. We give an empirical justification of the GARCH-NIG model using this approximation.</p><p>In addition, we introduce a new General GARCH(p,q)-NIG model. This model has as special cases the Threshold-GARCH(p,q)-NIG model to model the leverage effect, the Absolute Value GARCH(p,q)-NIG model, to model conditional standard deviation, and the Threshold Absolute Value GARCH(p,q)-NIG model to model asymmetry in the conditional standard deviation. The properties of the maximum likelihood estimates of the parameters of the models are investigated in a simulation study.</p>

<p>We investigate how the knowledge in knowledge technology applications for knowledge management can be represented to let the user directly manage the knowledge content of the applications.</p><p>In paper I we design a representation of diagnosis knowledge that allows the user to add new components and inspect the function of the device. The representation allows an integration of model based knowledge with compiled and heuristic knowledge so that the device and its function can be represented a suitable level of abstraction and let other parts be represented as non-model based knowledge.</p><p>In paper II we use simplified rules for describing the time, resources, activities and amounts required in a tunnelling project and a simulation engine for estimating time and amounts consumed in the tunnelling process. The rules are designed to allow a user to change the facts and computations of the system.</p><p>In paper III we present the constraint modelling language CML and show how to model a nurse scheduling problem and a train scheduling problem without programming. The idea is to preserve the problem structure of the domain, allowing constraint formulations that reflect natural language expressions familiar to the users. CML problem specifications are transformed automatically to standard constraint programs </p><p>In paper IV we investigate the use of decision tables for representing requirements on staff scheduling explicitly, providing structure, decision support and overview to the user. The requirements are compiled automatically to a program that use hand-written procedures for efficient scheduling.</p><p>It seems possible to let the user modify central parts of the knowledge content in the applications with these representations, by using various illustration techniques. The techniques used are object-based graphics for manipulating device components and connections in diagnosis, simplified rules for simulation of tunnelling activities, text-based query language specification of scheduling problems and finally, decision tables for constraint problems and decision support.</p>

We investigate how the knowledge in knowledge technology applications for knowledge management can be represented to let the user directly manage the knowledge content of the applications. In paper I we design a representation of diagnosis knowledge that allows the user to add new components and inspect the function of the device. The representation allows an integration of model based knowledge with compiled and heuristic knowledge so that the device and its function can be represented a suitable level of abstraction and let other parts be represented as non-model based knowledge. In paper II we use simplified rules for describing the time, resources, activities and amounts required in a tunnelling project and a simulation engine for estimating time and amounts consumed in the tunnelling process. The rules are designed to allow a user to change the facts and computations of the system. In paper III we present the constraint modelling language CML and show how to model a nurse scheduling problem and a train scheduling problem without programming. The idea is to preserve the problem structure of the domain, allowing constraint formulations that reflect natural language expressions familiar to the users. CML problem specifications are transformed automatically to standard constraint programs In paper IV we investigate the use of decision tables for representing requirements on staff scheduling explicitly, providing structure, decision support and overview to the user. The requirements are compiled automatically to a program that use hand-written procedures for efficient scheduling. It seems possible to let the user modify central parts of the knowledge content in the applications with these representations, by using various illustration techniques. The techniques used are object-based graphics for manipulating device components and connections in diagnosis, simplified rules for simulation of tunnelling activities, text-based query language specification of scheduling problems and finally, decision tables for constraint problems and decision support.

Hypermedia systems and knowledge systems can be viewed as flip sides of the same coin. The former are designed to convey information and the latter to solve problems; developments beyond the basic techniques of each system type require techniques from the other type. Both system types are frequently used in learning environments, and to different extent utilise user co-operation. A knowledge system consists of a formal representation of a domain theory enabling automated reasoning to take place within the domain. Since a formalisation cannot generally reproduce all relevant knowledge, the user's co-operation is needed to obtain a well functioning system. To perform well in this co-operation, the knowledge in the system must be accessible and transparent to the user. Tranparency can be achieved by means of explanations. In a learning environment transparency and co-operation are vital because the user needs to be active whilst the reasoning is being carried out - to be able to learn how to perform the problem solving. To achieve transparency we introduce the notions of inferential context and conceptual context. These allow explanations to be composed at various levels of abstraction and from different perspectives and not only exploit a formalisation, but also informal descriptions of the domain knowledge. This facilitates the user’s learning of the domain knowledge and thus his/her ability to co-operate with the system in the problem solving. We integrate techniques from knowledge systems and hypermedia in a system architecture. The architecture deals with formal and informal knowledge. The formal knowledge is used for the formal reasoning, which is based on knowledge systems techniques; the informal knowledge is exploited in this reasoning to generate explanations in different media. The relations between the formal and the informal theory are administered by a metatheory. The metatheory carries out the reasoning in the system and the communication with the user, i.e. the presentation of the explanations and the integration of the user's contribution in the reasoning. The system architecture is transparent, modular and promotes clarity, maintainability and reusability.

We discuss the Normal inverse Gaussian (NIG) distribution in modeling volatility in the financial markets. Refining the work of Barndorff-Nielsen (1997) and Andersson (2001), we introduce a new parameterization of the NIG distribution to build the GARCH(p,q)-NIG model. This new parameterization allows the model to be a strong GARCH in the sense of Drost and Nijman (1993). It also allows us to standardized the observed returns to be i.i.d., so that we can use standard inference methods when we evaluate the fit of the model. We use the realized volatility (RV), calculated from intraday data, to standardize the returns of the ECU/USD foreign exchange rate. We show that normality cannot be rejected for the RV-standardized returns, i.e., the Mixture-of-Distributions Hypothesis (MDH) of Clark (1973) holds. {We build a link between the conditional RV and the conditional variance. This link allows us to use the conditional RV as a proxy for the conditional variance. We give an empirical justification of the GARCH-NIG model using this approximation. In addition, we introduce a new General GARCH(p,q)-NIG model. This model has as special cases the Threshold-GARCH(p,q)-NIG model to model the leverage effect, the Absolute Value GARCH(p,q)-NIG model, to model conditional standard deviation, and the Threshold Absolute Value GARCH(p,q)-NIG model to model asymmetry in the conditional standard deviation. The properties of the maximum likelihood estimates of the parameters of the models are investigated in a simulation study.

Organisations depend on IT for successful completion of many organisational activities. A distinction can be made between organisations with an IT-dependency of type-1, where IT-artefacts perform earlier manual routines, and organisations with an IT-dependency of type-2, where organisations utilise already digital data to enable new or radically improved organisational processes. Recognition of IT-dependency indicates that the way IT-artefacts are related to organisations is important. Moreover, the ways in which such relations are subject to change have so far seldom been subject to research. Thus, the research question asked in this thesis is: How to sustain and further develop the ways IT-artefacts and activities become and continue as related in order to effectively support changed or new organisational activities? Within informatics we have been preoccupied with studying design of IT-artefacts. I found a design perspective inadequate to grasp the complexity of how IT-artefacts become related to organisational activities. Thus, as a secondary research question I ask: How can IT-artefacts and organisational activities they are intended to support be perceived and understood as fundamentally related? The research questions have methodological implications. Since I could not find a theory giving the answer to my complementary research question, I made it my business to produce one. Methodologically speaking this thesis to a great extent concerns theory construction. In answering the secondary research question I suggests an object of study comprising IT-artefacts and organisational agents co-producing organisational actions; informaction systems. An embryonic theory is outlined, based on Weick’s account of organising, describing mechanisms according to which ITartefacts and organisations become related. Assuming the embryonic theory of informaction systems to be valid some initial conclusions concerning my original research question can be deduced. (1) seeing an IT-artefact and organisational agent as an action-producing unit means that no one has unilateral control over the co-produced organisational actions. (2) informaction systems become established rather than implemented. (3) sustaining relations is not a design problem, instead it is usually connected to care, so my secondary research question needs to be characterised by a shift from a design mood to a care mood. (4) guidance of an activity in which there is no unilateral control and that has a lot to do with care is characterised by a shift from management to stewardship. (5) the idea that implementation of IT-artefacts dictates organisational behaviour has to be abandoned. Instead it is paramount importance to be sensitive to how IT-artefacts actually become made sense of and hence used and utilised. This can be characterised as a shift in focus from telling to listening. These conclusions are subsumed in an approach to my original research question I have named informaction systems stewardship.

What is identified as a problematic area in this thesis is our different relations with information technology which creates inequalities between possibilities to enjoy the advantages, or suffer the disadvantages, of the information technological development. The first step in addressing this area is to start with our conceptions of technological development, voluntaristic or deterministic, and the first argument is that it is important to create an awareness of our relation with technology. This thesis presents a perspective (with the help of social constructionism) which holds a possible method to create better conditions for awareness and finally, another relation. The relationistic approach highlights what sometimes is labelled the therapeutic purpose of IS (i.e. to create a mutual understanding between different agents through negotiated arrangements) which prevents some agents to be treated as inanimate objects instead of fellow human beings. And techno therapy not only for the IS researchers but for the change agents at the political level and perhaps most importantly, for the users themselves so that they will be able to formulate, communicate and mediate their needs and wishes. The aim is to come up with tools and instruments for creating opportunities for as many as possible to in an enlightened and equal way make their own choices regarding information technology use.

This thesis focuses on the delivery of government services to citizens with a particula r emphasis on enabling those who are at risk of exclusion from the digital society to gain access to it. Following in this direction, one of the frequently addressed issues concerning the accessibility of e-services and information in government websites is found to be the users’ unawareness concerning the location of the desired information or service. Consequently, the overall objective of the thesis is to find, develop, and assess a solution to provide citizens with a simple and effective means of accessing and utilizing e-government services in government websites. The solution might be seen as a contribution to preventing digital exclusion among citizens caused by difficulties associated with navigation and way-finding, as well as the complexity of the utilization of the digitally provided services. To gain this objective, the thesis argues for the use of a digital assistant; i.e. an embodied conversational agent able to provide the user with the desired services or information by means of a dialogue. Influenced by a real life situation, the overall idea behind the use of a digital assistant is that since knowledge about the arrangement of available drugs in a pharmacy and a particular drug's whereabouts in that organization is of little concern to customers, so too should knowledge of the organization and the whereabouts of services and information in a website be of little consequence to users. Therefore, a digital assistant is expected to act in a similar manner to a human agent who possesses knowledge regarding the existing infor mation and services, their application area, and where these are stored. In order to realize the defined objective, this thesis is organized to cover all stages of the research process; i.e. the identification of the users’ difficulties in the current sit uation, the development of a prototype of a digital assistant, and the assessment and evaluation of the suggested solution in both a laboratory environment and in a real life situation. The thesis concludes by gathering and placing the results of the conducted studies in to a bigger context to find out whether or not the use of digital assistants improves the delivery of e-government services and the citizen’s utilization of them, and also to clarify and present the research project’s practical and methodological findings. With reference to the findings addressing the identified difficulties in the currents situation, the conducted studies showed that a digital assistant solution, such as the one described in this thesis, offers contributions to the accessibility of e-government services. It was also found that a digital assistant could contribute to the delivery of egovernment services by: a) reducing the technology barrier caused by the traditional input/output technologies, b) reducing the navigation barrier caused by the conventional web design, c) reducing the mental load of the user, and d) adding benefits and subjective pleasing. The other interesting finding concerns the contribution of the digital assistant’s “approach” to the development of egovernment services. In other words, going from a traditional design of web interfaces to a digital assistant approach is similar to moving from an inside out perspective to a strictly customer or citizen oriented perspective. This shift in perspective could be recognized as a small revolution and it has many consequences for the development of e-government services compared to the current traditions. Taken together, these findings have lead to an improvement in the digital assistant developed in this thesis, and suggest possibilities for future work within this area of research.

Requirements engineering (RE) tools are software tools which provide automated assistance during the RE process. However, the RE practice relies on office tools rather than RE-tools provided by various companies. Reasons for not using the RE-tools include financial causes. The part of the problem also lies in the difficulty to evaluate such tools before acquisition to support the RE process. Hence, to support the completeness and effectiveness of RE-tool evaluation, a sound framework providing methodological guidelines is needed. This work proposes an RE-tool evaluation approach (R-TEA), which provides a systematic way of the RE-tool assessment using two evaluation frameworks. The framework for the functional RE-tool requirements consists of three dimensions: representation, agreement, and specification. The representation dimension deals with the degree of formality, where requirements are described using informal, semiformal and formal languages. The agreement dimension deals with the degree of agreement among project participants through communication means. The specification dimension deals with the degree of requirements understanding and completeness at a given time moment. The second framework categorises the non-functional RE-tool features to process, product, and external requirements. Process requirements characterise constraints placed upon the user’s work practice. Product requirements specify the desired qualitative characteristics of RE-tools. External requirements are derived from the user’s internal and external environment. Both frameworks are applied to a specification exemplar which application initiates preparation of the requirements specification for the RE-tool selection. Assessment of the RE-tools’ compatibility to the specified RE-tool requirements is performed using different evaluation techniques. Decision about RE-tool selection is made after summarising all the assessment results. A prototype tool is developed supporting the frameworks and R-TEA. The R-TEA method is tested in a number of case studies. The findings report on positive trends of the frameworks, prototype and the R-TEA method.

Intranets appeared in the mid-1990s and were perceived as the answer to the need for the integration of existing Information Systems into organisations. Despite the fact that there has been extensive research regarding implementation, development processes, policies standardisation vs. creativity and so forth, the potentiality of Intranets has not been fully exploited. Intranets offer many advantages in the form of working networks that support and enable empowered employees to participate in the development of the organisation, to enable the measurement of essential functions and to monitor undesired conditions and find suitable functions that support daily work. The research approach in this thesis has alternated between analysis empirical studies, and design. Current literature, research findings in the form of articles, etc., are analysed, an empirical study of five organisations is conducted and finally a design of possible functions is accomplished. In the analysis of the state-of-the-art, current research can be grouped into four topics partly overlapping each other; questions concerning informatics, organisation theory, knowledge management, and design. Urgent issues for further research are identified as mainly belonging to the topics informatics and organisation theory; management and strategy, empowerment, further development processes, use, and roles. Findings from a study of five Swedish organisations show a need for identifying the philosophy of technology in the organisations in order to make an organisation’s view of technology common throughout the organisation. Furthermore, functions supporting daily work are lacking to a high degree. Further lacks and demands are identified, as well as potential functions and new possibilities. In the next section, the Philosophy of Technology is related to an Intranet. The discussion is based on a model which consists of the concepts Conception, Use, Technology, and Policy. Making the Philosophy of Technology common in organisations is connected to the empowerment of employees and is a guarantor, along with the influence of the VSM on the design, for the impact on and participation in the processes of an organisation. The next part deals with possible advantages of combining the cybernetic model, the Viable System Model, by Stafford Beer, and an Intranet. It is found that the VSM can support the design of Intranets according to essential functions such as Early Warning Systems connected to production units and levels that are to be made aware of undesired conditions in the organisation. Furthermore, functions for amplifying and attenuating information – both between parts of the organisation and between the organisation and the environment – are to be designed. Further examples of functions supporting the organisation, in order to make it viable, are given. The main contribution of the thesis is the identification of core functions in an Intranet as establishing functions for supervision (Early Warning Systems), attenuating and amplifying information between the organisation and the environment and between subparts in the organisation. Furthermore, the interface is to be designed so the underlying technology is “visible:” Where are the different parts of the Intranet located physically? Who delivers information to the different parts? Who uses the functions? Who is responsible? The transparency of the interface makes the philosophy of technology visible throughout the organisation; the concepts are the same, the actual use is the same as the intended use, and policy is active and well known and finally, the possibilities and the limitations with/inherent to an Intranet are known among the users. Finally, examples of further research are given – both as regards the implementation of Intranets based on the VSM design and as regards making the interface transparent.