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Television is now changing its traditional distribution forms to being distributed digitally over broadband networks. The recent development of broadband Internet connectivity has made the transition to Internet Protocol Television (IPTV) possible. When changing distribution technique of an existing service, it is important that the new technique does not make the service worse from the user’s point of view. Although a broadband network offers high capacity and has excellent performance there will be occasional packet losses and delays which could negatively influence the user experience of the delivered broadband service. Since bandwidth is a key constraint for video distribution there is a strong incentive for finding schemes to increase bandwidth utilization, especially when distributing high bandwidth IPTV services. In digital video coding it is common to use predictive coding to remove temporal redundancy in video sequences. This technique greatly increases the coding efficiency but makes the sequence more sensitive to information loss or delay. In addition, the use of predictive coding also introduce a inter frame dependency which could make the channel change significantly slower. This thesis addresses two important areas related to bandwidth efficient IPTV distribution, namely error resilience and fast channel change. A method to numerically estimate the decoded objective video quality of scalable coded video is presented and evaluated. The method can be used to estimate objective video quality for a scalable video transmission system subject to packet-loss. The quality gain of temporally scalable video in a priority packet dropping environment is also investigated and quantified. Synchronization Frames for Channel Switching (SFCS) is proposed as a method to code and distribute video with IP-multicast, which can be used to efficiently combat packet-loss, increase bandwidth utilization, and offer a channel change speed up. The performance of SFCS is analyzed and bandwidth estimation expressions are formulated, analytical results are complemented with computer simulations. The results show that SFCS deployed in an IPTV delivery system can significantly lower the bandwidth consumption and speed up the channel change.

Text clustering divides a set of texts into clusters (parts), so that texts within each cluster are similar in content. It may be used to uncover the structure and content of unknown text sets as well as to give new perspectives on familiar ones. The main contributions of this thesis are an investigation of text representation for Swedish and some extensions of the work on how to use text clustering as an exploration tool. We have also done some work on synonyms and evaluation of clustering results. Text clustering, at least such as it is treated here, is performed using the vector space model, which is commonly used in information retrieval. This model represents texts by the words that appear in them and considers texts similar in content if they share many words. Languages differ in what is considered a word. We have investigated the impact of some of the characteristics of Swedish on text clustering. Swedish has more morphological variation than for instance English. We show that it is beneficial to use the lemma form of words rather than the word forms. Swedish has a rich production of solid compounds. Most of the constituents of these are used on their own as words and in several different compounds. In fact, Swedish solid compounds often correspond to phrases or open compounds in other languages. Our experiments show that it is beneficial to split solid compounds into their parts when building the representation. The vector space model does not regard word order. We have tried to extend it with nominal phrases in different ways. We have also tried to differentiate between homographs, words that look alike but mean different things, by augmenting all words with a tag indicating their part of speech. None of our experiments using phrases or part of speech information have shown any improvement over using the ordinary model. Evaluation of text clustering results is very hard. What is a good partition of a text set is inherently subjective. External quality measures compare a clustering with a (manual) categorization of the same text set. The theoretical best possible value for a measure is known, but it is not obvious what a good value is – text sets differ in difficulty to cluster and categorizations are more or less adapted to a particular text set. We describe how evaluation can be improved for cases where a text set has more than one categorization. In such cases the result of a clustering can be compared with the result for one of the categorizations, which we assume is a good partition. In some related work we have built a dictionary of synonyms. We use it to compare two different principles for automatic word relation extraction through clustering of words. Text clustering can be used to explore the contents of a text set. We have developed a visualization method that aids such exploration, and implemented it in a tool, called Infomat. It presents the representation matrix directly in two dimensions. When the order of texts and words are changed, by for instance clustering, distributional patterns that indicate similarities between texts and words appear. We have used Infomat to explore a set of free text answers about occupation from a questionnaire given to over 40 000 Swedish twins. The questionnaire also contained a closed answer regarding smoking. We compared several clusterings of the text answers to the closed answer, regarded as a categorization, by means of clustering evaluation. A recurring text cluster of high quality led us to formulate the hypothesis that “farmers smoke less than the average”, which we later could verify by reading previous studies. This hypothesis generation method could be used on any set of texts that is coupled with data that is restricted to a limited number of possible values. / QC 20100806

HTML clipboardThe thesis deals with the dual problem of finding out and modelling the needs of users in various situations and constructing models of supportive software. Task analysis has not been a very hot topic for research in the last years, but in my work I have tried to apply task analysis to certain application areas. In this thesis the focus is therefore on two different kinds of applications, the first being a traditional software application, electronic mail systems. The second application area is programming of service robots for the home, and specifically robots that are intended as support for people with functional disorders, e.g., as a result of neural diseases or accidents with neurological consequences. The work in the thesis spans over a long period of research, but there is a thread going through the thesis based on a perspective that regards work tasks as consisting of sequences of patterns. In the e-mail application area, the pattern theory was not outspoken, but can be seen in the software prototyping tool, GRASP, that was developed in pure Prolog. The task pattern system, TAPAS, that was developed from the work in robots and the interviews with people with various degrees of disorders is clearer on the pattern approach. With the GRASP system, the idea was that users could be involved in the development through prototyping tools that would enable a more individual design of the application and the interface functionality. When this was taken into the area of design for inclusion, it was clear that the pattern approach in TAPAS would need to cater for an individual design of the robot’s tasks. Individualisation is a costly process but it can be eased through the use of a pattern approach to task modelling. The conclusion of the work in this thesis is that task analysis and conceptual modelling still have application areas within software development, especially where there is a large need for individual adaptation of the applications (such as robots as support for people with functional disorders). I show that a combined knowledge elicitation method and task modelling tool based on a pattern-based perspective can facilitate a more flexible and individual design of software. More precisely, in the robot context, I show that a robot that is programmed through a pattern approach receives a potential to become flexible enough to allow for end user reprogramming under certain circumstances. The conclusion of my work is that task analysis in combination with conceptual modelling of tasks as patterns is a promising method combination for the programming in task areas where there is a large need for individualization and flexibility. / QC 20100804

The research problem explored in this thesis is how technology and work practice are related in coordinative situations (collocated and over distance). Further, the problem of how this kind of research results can be transformed and used in the development of new technology is discussed. Air Traffic Control and Emergency Call Centers are the two domains where the complex process of coordination in a time and safety critical setting has been studied. The methodological approach taken in the field studies is ethnographic, a qualitative method with a descriptive outcome. Air traffic controllers focus on keeping the airspace organized so that the aircraft are separated at all times, as well as are given an economic route by e.g. slowing down so that they do not have to wait in the air for traffic ahead. In order to manage the control of the national airspace, it is divided into geographical sectors each of which is controlled by 1-2 controllers. The aircraft cross many sectors during one flight and each time they cross a sector border there is a handover of responsibility between the controllers. The controllers have a large number of tools that they orchestrate in order to maintain control and keep records of the orders given to the pilots. The situation in one sector has therefore been locally stored at their work position. It is shown in the thesis how the social interaction and the technology support are ordered to broadcast the locally stored information. Emergency call centers at SOS Alarm are in contrast to the ATC centers fully computerized. The operators use CoordCom, a system that is currently in the process of being renewed. When a telephone call to the emergency number 112 is received in one of the 20 local centers in Sweden, a receiving operator initiates the case by interviewing the caller in order to categorize the incident. Often, an incident consists of a number of conditions that together make an emergency. It is shown that accountability of decisions and local knowledge of the center’s responsibility area are two important parts of coordination at SOS Alarm. A question that has been of interest during the studies is what possibilities ethnographic observations provide when used as a starting point in a design project. The final study provided a description of how the ethnographic material from the emergency call center study was explored and transformed in order to create concrete functionality and design. The thesis contributes with examples from the workplace studies of how people interact with each other through the technology and how skills, local knowledge and professional concerns shape the interaction. It also contributes with reflections on how descriptions and experiences of work practice and technology use in the field can serve as a foundation in shaping and designing new ideas and new functionality for future systems. The papers included in this thesis shows results on four issues in relation to coordination and technology: -Coordinative work practice and implications in using video/audio in a distributed setting -Support for accountability in decision-making in a distributed setting -The role of local knowledge and combined expertise in a local collocated center -The transformation of ethnographic observations in the design process The thesis also shows the importance of a further definition of the dichotomy of collocated and distributed work in order to inform technology. An analysis of the dichotomy based on the field study results is presented in the thesis. / QC 20101014

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Studentportalen är tänkt att vara ett hjälpmedel för studenterna under deras studietid genom att tillhandahålla olika tjänster och funktioner som behövs för studierna. är kan studenterna bland annat registrera sig på kurser, anmäla sig till tentor, beställa intyg och skapa scheman. Jag gjorde en enkätundersökning bland universitetets studenter där för att utreda vad de har för åsikter om tudentportalen, e-postsystemet och, till viss del, tudentwebben. ndersökningen behandlade bland annat inloggning, länkstruktur, tudentportalens tjänster och funktioner avseende enkelhet att hitta dem samt information om och inlärning av dem samt hjälpfunktionen. Resultatet visade att studenterna har många bra ideer om hur tudentportalen kan förbättras. dagens samhälle blir användbarhet mer och mer viktigt och de önskade förbättringarna av tudentportalen skulle öka dess användbarhet. om det ser ut nu så loggar studenterna inte in i tudentportalen så ofta som systemägarna vill. Undersökningen visade att studenter i genomsnitt loggar in på tudentportalen mer sällan än varannan vecka, vilket kan bero på att tudentportalen inte tillhandahåller funktioner och tjänster som behöver användas minst en gång i veckan. om ett exempel finns  tentamensanmälningen som förvisso kan behöva användas några gånger per termin men inte så ofta som en gång i veckan. ystemet behöver således attraktiva funktioner och tjänster som lockar studenterna till tudentportalen. Under hösten 2007 byttes studente-postsystemet ut mot ett nytt system, kallat e-GO. Denna studente-post bygger på oogles teknik och ger studenterna tillgång till ett stort lagringsutrymme och även en del andra tjänster. etta system fick positiv kritik av studenterna tack vare dess stora lagringsutrymme. Då denna uppsats är tänkt att ligga till grund för systemförvaltarnas vidare utveckling av tudentportalen så hoppas jag att den information som framkom av enkätundersökningen kommer att vara till hjälp och att systemet utvecklas så som studenterna önskar.

<p>en här rapporten tar upp planering av informationsinnehållet i intranät. Ett intranät är ett kommunikationsmedium som möjliggör spridning av information inom ett företag eller organisation. Undersökningen är gjord som en fallstudie på personalfunktionen vid Skaraborgs sjukhus som under våren har påbörjat arbetet med ett intranät. Undersökningen har gett resultat i form av konkret information som informationslämnare och användare vill se i personalfunktionens intranät. Undersökningen har även gett svar på om interaktiv information bör finnas i personalfunktionens intranät samt om informationen bör anpassas till olika användare.</p>

<p>Detta arbete behandlar huvudsakligen de båda företeelserna intelligenta mjukvaruagenter och informationsstress. Syftet med arbetet har varit att undersöka om olika former av intelligenta mjukvaruagenter har förmåga att i en positiv riktning påverka de faktorer som kan orsaka informationsstress. Arbetet har bedrivits genom dokumentstudier och en intervjustudie. Genom dokumentstudien söktes exempel på faktorer som kan orsaka informationstress, samt former av intelligenta mjukvaruagenter som skulle kunna påverka dessa faktorer. Intervjuerna genomfördes med personer från olika personalgrupper i Vara kommun, vilka alla hade det gemensamt att de dagligen kom i kontakt med någon form av IT. Resultatet av arbetet tyder på att vissa former av intelligenta mjukvaruagenter har förmåga att i en positiv riktning påverka de faktorer som kan orsaka informationsstress, men att användningen av dessa mjukvaruagenter samtidigt kan föra med sig andra faktorer som kan orsaka andra former av stress.</p>

<p>När en organisation inför distansarbete blir tillfällena till kommunikation ansikte mot ansikte på arbetsplatsen mer begränsad än tidigare.</p><p>I denna undersökning har jag därför studerat hur kommunikationen påverkas vid införande av distansarbete i en organisation. Jag har undersökt både den informella och den formella kommunikationen och kommunikationen mellan medarbetare och mellan medarbetare och chefer. För att få fram information, har jag gjort en litteraturstudie samt intervjuer.</p><p>Jag har dels studerat organisationer som har infört distansarbete för att få fram deras erfarenheter av hur kommunikationen har påverkats av distansarbete. Dels har jag även studerat organisationer som inte infört distansarbete för att ta reda på deras åsikter avseende kommunikationen vid distansarbete.</p><p>Med min undersökning som grund anser jag att det är viktigt för organisationen att noga gå igenom de förändringar som kommer att ske vid införande av distansarbete och ha klara riktlinjer för hur kommunikationen skall ske.</p>