<p>Large data centers are used for large-scale high-performance tasks that often includes processing and handling sensitive information. It is therefore important to have access control systems that are able to function in large-scale data centers. This thesis looks into existing solutions for the authentication step of access control in large data centers, and analyses how two authentication systems, Kerberos and PKI, will perform when employed on a larger scale, beyond what is normal in a large data center today. The emphasis in the analysis is on possible bottlenecks in the system, computational power spent on access control routines, procedures for administration and key distribution and availability of extension features needed in large scale data center scenarios. Our administration analysis will propose and present possible methods for initial key distribution to new machines in the data center, as well as methods for enrolling new users. We will also propose a method for automatic service instantiation in Kerberos and present a method for service instantiation in PKI. We will look at how the systems handle failed machines in the network, and look at how the systems handle breaches of trusted components. Our performance analysis will show that under given assumptions, both Kerberos and PKI will handle the average load in a hypothetical data center consisting of 100000 machines and 1000 users. We will also see that under an assumed peak load, Kerberos will be able to handle 10000 service requests in under 1 second, whereas the PKI solution would need at least 15 seconds to handle the same number of requests using recommended public key sizes. This means that some programs may need special configurations to work in a PKI system under high load.</p>

<p>While rigorous, mathematical techniques are helpful for improving the quality of software engineering, the threshold of learning and adapting formal methods keep many practitioners from embracing these kinds of approaches. We present the emph{Arctis Analyzer}, a tool for supporting a developer by formal methods, without the developer having to understand any formal language. To realize this tool, we developed an extensible analysis framework that is used by the analyzer to assist the user when problems are encountered. We combine model checking with syntactic analysis so as to provide a developer with not only symptoms, but also diagnoses and fixes for the underlying flaws in the specifications. Our work is based in SPACE, an approach for specifying reactive and distributed systems. In this approach, systems are composed of service specifications as opposed to traditional component specifications. Services are expressed by UML collaborations and activities representing their structure and behavior, respectively. This work focuses on analyzing the behavior of the services, hence on the UML activities. The analyzer transforms the UML models into tlaplus{}, the language of the Temporal Logic of Actions, TLA. It also generates TLA theorems for a number of properties that should hold. In order to detect property violations, the tool uses the model checker TLC to check the entire state space of the formal specifications. The analyzer can visualize any error traces from TLC in terms of the graphical model that the user is working on. This thesis presents the analyzer and how it is implemented. It also presents the analysis framework detailing twelve theorems, eleven symptoms, seven diagnoses and nine fixes. Out of these, ten theorems, six symptoms, three diagnoses and two fixes, have been implemented in the analyzer as proof of concept. The thesis also contains a number of examples showing the use of the analyzer within Arctis.</p>

<p>Today, there are still different technologies used in fixed and mobile networks environment such as cellular technologies (GSM, UMTS, 3G, etc.), wireless network technology like WLAN, wired network technology like ADSL, etc. With the usage of IMS (IP Multimedia Subsystem), all those technologies can be combined together in a fixed mobile convergence environment based on an IP-based infrastructure. Although IMS applies well for a Fixed Mobile convergent environment, there are still issues that need to be solved. First, the IMS central protocol is SIP but there are differences between the 3GPP SIP specifications and the IETF one. This will lead to interoperability problem with different SIP specifications, and the devices between different SIP environments cannot communicate with each other. Second, IMS for a fixed mobile environment should also allow the users to subscribe to any type of services (fixed or mobile), to get access to services on an arbitrary number of registered mobile and fixed devices interchangeably, to dynamically add or remove the number of registered fixed devices. In fact, the general IMS infrastructure is only a high-level scheme and does not support the mentioned requirements. Therefore, in order to satisfy all the mentioned requirements it is crucial to have a sound identity management solution. The goal of this thesis work is to propose a sound identity management solution for a fixed mobile convergent IMS environment. More specifically, the thesis work will be aiming at the following objectives: • To provide a concise but clear introduction to Identity Management • To provide a comprehensive description on how identities are organized and managed in both fixed and mobile networks • To propose an identity management solution for a fixed mobile convergent IMS environment • To demonstrate the soundness and feasibility of the proposed solution via the implementation of a prototype. Two Identity Management solutions have been proposed and analyzed as follows: 1. Modified IMS and SSO-enabled SIP system 2. Modified SIP-enabled Client Due to time limitation, only the second solution is selected and a proof-of concept has been successfully designed and implemented. The proof-of-concept has demonstrates the following features: • Single-Sign-On between the Mobile and Fixed domain enabling a mobile phone moving from the IMS mobile network to a SIP WLAN network without re-authentication. • Identity Federation between the Mobile and Fixed domain enabling the delivery of calls addressed to one domain at the other domain.</p>

<p>The focus of this work is the rapid engineering method SPACE, developed at NTNU. In this method, services are modeled using UML 2.0 collaborations and activities, and from these executable code can be generated. Services can be composed from other services and building blocks. Until recently, SPACE has only focused on control flow. We have extended SPACE by introducing data flow modeling into SPACE activities. This raises some important questions, for example, how data between building blocks may be shared. We discuss a number of possible solutions. Our work is driven by the UNO card game as an example application. The structure and behavior of the UNO card game is analyzed and discussed, highlighting and exemplifying the aspects discussed in this work.</p>

<p>The development in advertising industry has lately gone from open advertising through few, major distribution channels to a hidden and targeting advertising integrated into everyday life. Advertisers grow increasingly unhappy with the value delivered by the traditional mediums. They turn to alternative distribution channels in order to increase the success rate of advertising campaigns. Channels seen as unattractively with little purchasing power previously are attracting advertisers’ attention. The goal of this thesis has been to identify future distribution channels for advertising through computer games and mobile devices. In addition to identify, the report aims to look into the market potential of the identified advertising channels as well. This thesis begins with an introduction to advertising. Then advertising in computer games are investigated in the next chapter. The audience and business aspects of this advertising branch are examined and existing distribution channels are presented. Then a case study of advertising in a computer game named Cricket 07 and a virtual world called Second Life are carried out. Based on the thorough case study, several unexploited advertising channels are found and presented. The concepts are described in detail and high-level technical models are presented. The second part of the thesis examines mobile advertising. The same procedure is used here as for advertising in computer games. The main contribution of this part is the proposed solution presented in the end of the chapter. An advertising channel tailor made for Wireless Trondheim is described and a high-level technical model of the proposed distribution channel is given. The main contribution of this thesis is the identification of new distribution channels for advertising through computer games and mobile devices.</p>

<p>A home network is a popular method of allowing computers to communicate with each other within a given residential area or a local area network. Homes are the new frontiers of technology in the current global scenario, a digital interconnected home network is a reality and an efficient means to exchange information seamlessly across different homes and across different geographies is the need of the hour. The interconnection of different homes is possible with the existing ADSL subscriptions but would need changes in the existing gateway structures, which could be challenging for the less techno-savvy. In an effort to make life easier for the end user and help making the interconnection between various home networks seamless, a small device called I-Box is introduced through this project, which is essentially a small UPnP device with rich features and functionalities. This thesis gives an overview of the I-Box technology and with the help of various popular theoretical frameworks and concepts, investigates available Marketing channels and suggests a suitable deployment strategy for the I-Box by making a comparative study of the various possible scenarios and thereby identifying the most suitable model for its deployment.</p>

<p>With the appearance and expansion of mobile devices, ubiquitous computing is becoming more popular nowadays and the user and his tasks are becoming the focus of application development. One area of ubiquitous computing is composed by the context-aware systems, systems where applications are designed to react to the constant changes in the environment. The heterogeneity of the different domains where context is a key parameter has generated different approaches for context acquisition and modeling. Thus, a number of platforms have been developed in order to alleviate the process of application development and to set a common practice for building applications and services. This thesis studies the different platforms, focusing on the Context Toolkit. It examines the design principles, context representation, context acquiring methods and context handling. By developing services for a smart home, it explores the mechanisms applied in the framework and evaluates it. Furthermore, proposals for improving the Context Toolkit’s functionality and the application’s performance are given, by introducing the concept of quality of context and several enhancements regarding the resource discovery mechanism. Consequently, after gaining hands-on experience with developing a sample context-aware application and analyzing the Context Toolkit, a context-aware platform design is proposed which offers a complete solution defining all the necessary components and their interactions.</p>

<p>The significant growth in mobile markets exposes business niches. A number of heterogeneous services have been offered to end users by several service providers. The end users can fully benefit from wide varieties of services only when these heterogeneous services can be composed together (i.e. service composition is created). This fact motivates an invention of frameworks that support diverse features such as service creations and compositions. The frameworks aid new market players to enter and offer innovative services. Such frameworks could benefit users by offering a big pool of services, and service providers by simplifying deployment process in adopting groundbreaking services. To achieve this, SPICE (Service Platform for Innovative Communication Envi-ronment) project has been established. In SPICE project, the researchers have developed, among other things, two environments: a Service Creation Environment (SCE) and a Service Execution Environment (SEE). An objective of SCE is to create and compose web services and Telecommunication services. An objective of SEE is to execute compositions of the services created by SCE. Main component developed in SCE is Automatic Composition Engine (ACE). ACE dynamically constructs service composition that satisfies a request of service developers. The request has to be constructed in a formal way. Therefore, the informal request such as natural language request (i.e. in English) needs to be transformed into a formal service com-position request before it is sent to the ACE. Thus, clients of ACE are only limited to service developers who have enough knowledge to construct the formal request. To bring SCE out to the market where end users do not possess much of technical knowledge, this thesis proposes a development of Intelligence Agent (IA) as a new component of SCE. IA construct service composition from an informal request in natural language by using Natural Language Processing (NLP) technique. A context handling feature has also been considered in this thesis. In SPICE project, the researches have developed Knowledge Management Framework (KMF) that supports context handling. This thesis demonstrates a possibility to integrate IA with KMF so as to improve SCE. As a result of this thesis, we have developed a prototype of IA. IA receives a request from end user in natural language (English), analyze the request, search and compose for service composition candidates that satisfy the request and deploy the candidates into an artificial language, SPATEL. We have also developed a module of IA that registers and subscribes for a user context published by a knowledge source in KMF framework. IA takes into account a context of user (e.g. user location, user authentication) when it selects services from the service repository. IA also ensures that the desired service composition will be deployed when certain condition on user context arises.</p>

<p>Many topics have been touched in this thesis. I would like to conclude with some answers to the questions raised in the initial problem description and point out further challenges in some cases. We have seen that there exist several approaches for CALL, with virtual learning communities as one example. The community presented here, moodle.org, is an open source framework and let any user register for free and manage a course. In that way may this framework be used by school institutions, professional language course providers and other users who feel free to organize a course. This environment is quite formal in nature, because most of the use at the portal is related to a registered course. Another portal, italki.com, offers language learning after the tandem method and users are free to search among all (visible) profiles on the sites to find a match. This is a more informal framework as the users are not connected to any established educational institution, they do not necessarily follow a curriculum and the learning is not instructed to follow any pedagogical principles. These portals may be accessed both in stationary and mobile environments (by mobile browsers). In the case of mobile environments there exist many challenges: Developers of the site are requested to take special considerations of how some material is to be structured to fit the interface at the user’s terminal. One of the considerations at moodle.org was for instance to limit graphical content (illustrated in chapter 5.2.1), as this takes up much space on the screen and uses quite a bit bandwidth to download. Other challenges can be related to media richness and context awareness discussed in chapter two. One example could for instance be a video conference lecture held at a moodle course. If some of the users are in a mobile environment without the possibility to transfer video (because of terminal or bandwidth limitation), they should still be given the option of following the lecture by audio transmission. This will reduce the richness of the lecture, but they will be able to catch up the most essential things. BBC offers another kind of framework which is typically meant for beginner learners in a language. The material in ‘Language steps’ is instructional and interactive, as it requires response and apprehension from the users. This makes it most suitable for stationary environments, but the content could be presented in a mobile environment to. The 3 “Rearranging the dialogue” task will probably be suitable for a touch screen handheld. The content in the different modules could also be categorized to fit the current response flexibility of the user. An example of different categories was given in chapter 2. Another framework presented from the BBC portal was their show “The Flatmates”. This is an internet based soap show where the episodes can be followed by downloadable tracks or simply be read. The users may contribute to the show with discussion about the characters and give feedback about how the show should continue. This is a good example of how the Internet can be used as a platform for participation among users. There also exist mobile applications like KODI’s dictionary and Coolgorilla’s audio phrase books. These can be categorized as referential tools and can be used in many settings, remarking that the audio phrase books in most cases are suited for beginners on vacation in the target language country. Chapter 6 discussed general possibilities and challenges related to technology and market trends. Web 2.0 was presented as the future trend of Internet usage and web design with key words as creativity, information sharing and collaboration between users (and companies). A survey, held by the Norwegian institute ITU has showed that Norwegian teenagers at average participate in 3,4 ‘network societies’. Facebook was the most popular. The biggest reason to participate in the networks was to meet friends. Only 8 percent answered that the networks provided help for school related topics. This shows that most of the interaction in these networks are informal among the teenagers. Could we still expect more participation in school related topics in such networks? The answer is yes, and no. The technology exists to promote school related subjects in these networks, but it would be a challenge to mix the pupils’ (and the teacher’s) roles in such a situation, as depicted in chapter 6.3. Hans Christian Arnseth also points out in [46] that the question about using more web 2.0 applications in the school system is much about ideology – “What do we regard as proper learning and how can/should technology be used in the education?”. At last were some general challenges related to technology presented, with issues around convergence, human aspects, business models and policy as the main issues. Copyright policy and business models can be even more complicated in the evolution of web 2.0 interfaces, where content sharing and user participation goes hand in hand.</p>

<p>The purpose of this master thesis was to investigate the psychological and computational basis for human behavior representation (HBR) in military simulations and identify problem areas of existent software agent frameworks that provide computer generated forces (CGF) with human like cognitive abilities. The master thesis identifies psychological properties that influence human cognition in an operational environment through a theoretical study of operational and cognitive psychology. The psychological properties of human cognition are then connected to artificial intelligence through a theoretical study of agents and multi-agent systems and form the foundation for identifying general HBR properties. The HBR properties are used as evaluation markers that constitute the basis for constructing an evaluation of relevant agent frameworks thereby visualizing their strengths and weaknesses. The problem areas of incorporating artificial intelligence into CGF are further concretized by the development of a demonstrator that interacts with a synthetic environment. The demonstrator is an implementation of a tank platoon in the agent framework Jadex. The synthetic environment is provided by VR-Forces which is a product by MÄK technologies. The thesis makes a distinction between the conceptual structure of agent frameworks and their actual implementation. According to this master thesis it is the output of the agent framework that is the most important feature not how the output came into being. Producing the correct output requires the selection of the correct tools for the job. The selection of an agent framework should be taken on the background of an evaluation of the simulation requirements. A large portion of the development time is consumed by the development of application and communication interfaces. The problem is a result of lacking standardization and that most cognitive agent frameworks are experimental in nature. In addition the artificial intelligence (AI) in such simulations is often dived into levels, where the synthetic environment takes care of low-level AI and the agent framework the high-level AI. Tight synchronization between low and high-level AI is important if one wishes to create sensible behavior. The purpose of an agent framework in conjunction with CGF is thereby ensuring rapid development and testing of behavior models.</p>