This thesis contributes toward understanding fundamental limits of multi-user fading channels and random wireless networks. Specifically, considering different samples of channel gains corresponding to different users/nodes in a multi-user wireless system, the maximum number of channel gains supporting a minimum rate is asymptotically obtained. First, the user capacity of fading multi-user channels with minimum rates is analyzed. Three commonly used fading models, namely, Rayleigh, Rician and Nakagami are considered. For broadcast channels, a power allocation scheme is proposed to maximize the number of active receivers, for each of which, a minimum rate Rmin>0 can be achieved. Under the assumption of independent Rayleigh fading channels for different receivers, as the total number of receivers n goes to infinity, the maximum number of active receivers is shown to be arbitrarily close to ln(P.ln(n))/Rmin with probability approaching one, where P is the total transmit power. The results obtained for Rayleigh fading are extended to the cases of Rician and Nakagami fading models. Under the assumption of independent Rician fading channels for different receivers, as the total number of receivers n goes to infinity, the maximum number of active receivers is shown to be equal to ln(2P.ln(n))/Rmin with probability approaching one. For broadcast channels with Nakagami fading, the maximum number of active receivers is shown to be equal to ln(ω/μ.P.ln(n))/Rmin with probability approaching one, where ω and μ are the Nakagami distribution parameters. A by-product of the results is to also provide a power allocation strategy that maximizes the total throughput subject to the rate constraints. In multiple-access channels, the maximum number of simultaneous active transmitters (i.e. user capacity) is obtained in the many user case in which a minimum rate must be maintained for all active users. The results are presented in the form of scaling laws as the number of transmitters increases. It is shown that for all three fading distributions, the user capacity scales double logarithmically in the number of users and differs only by constants depending on the distributions. We also show that a scheduling policy that maximizes the number of simultaneous active transmitters can be implemented in a distributed fashion. Second, the maximum number of active links supporting a minimum rate is asymptotically obtained in a wireless network with an arbitrary topology. It is assumed that each source-destination pair communicates through a fading channel and destinations receive interference from all other active sources. Two scenarios are considered: 1) Small networks with multi-path fading, 2) Large Random networks with multi-path fading and path loss. In the first case, under the assumption of independent Rayleigh fading channels for different source-destination pairs, it is shown that the optimal number of active links is of the order log(N) with probability approaching one as the total number of nodes, N, tends to infinity. The achievable total throughput also scales logarithmically with the total number of links/nodes in the network. In the second case, a two-dimensional large wireless network is considered and it is assumed that nodes are Poisson distributed with a finite intensity. Under the assumption of independent multi-path fading for different source-destination pairs, it is shown that the optimal number of active links is of the order N with probability approaching one. As a result, the achievable per-node throughput obtained by multi-hop routing scales with Θ(1/√N).

The present study examines typical features of internet language found in user-generated comments collected from commenting groups from four online magazines aimed at different readerships: (1) adult women (Working Mother and Mothering), (2) adult men (Esquire), (3) young women (Seventeen) and (4) young men (Gameinformer). Approximately 5,000 words from each commenting group were collected, creating a 21,087 word corpus which was analyzed with regard to typographic (emoticons, nonstandard typography of and, personal pronouns you and I) and orthographic features (abbreviations, acronyms) as well as syntactic and stylistic features resembling spoken language (contracted forms, ellipsis of subject and/or verb and commenting tone). The results show that adult men wrote the longest comments, followed by adult women, young men and young women in descending order. Furthermore, as for the typical features regarding typography and orthography, it was found that among the four commenting groups, adult men and adult women used them very sparsely, young men used them occasionally and young women used the features most frequently. The analysis of tone showed that adult men mostly used an aggressive or neutral tone, while adult women, young women and young men mostly used a friendly or neutral tone. Young women used an aggressive tone more often than adult women and young men. Moreover, regarding the syntactic and stylistic features, results revealed that the young men were the most frequent users of ellipsis of subject and/or verb, followed by adult women, young women and adult men. Contracted forms were used extensively in the potential places of contractions, regardless of commenting group. Since young men used the ellipsis of subject and/or verb most frequently of all commenting groups and also used the contracted forms in all potential places of contractions, the conclusion is that the young men used a style that is closer to spoken English than the three other commenting groups. / Den här studien undersöker språkdrag som är typiska för språk på internet. Det material som har undersöks har hämtats från användarkommentarer i nättidningar som är riktade till fyra olika läsargrupper: (1) kvinnor (Working Mother, Mothering), (2) män (Esquire), (3) unga kvinnor (Seventeen) och (4) unga män (Gameinformer). Cirka 5 000 ord hämtades från kommentarsfälten för varje tidning, vilket resulterade i en korpus som omfattade 21 087 ord totalt. Korpusen analyserades med hänsyn till typografiska språkdrag (smileys, ickestandardiserad stavning av personliga pronomen I och you samt and) och ortografiska språkdrag (förkortningar, akronymer) samt syntaktiska och stilistiska språkdrag som påminner om talspråk (sammandragningar, ellips av subjekt och/eller predikatsverb, tonläge). Resultaten visade att män skrev de längsta kommentarerna, följda av kvinnor, unga män och unga kvinnor i fallande ordning. Vad gäller typiska typografiska och ortografiska språkdrag visar resultatet att de återfanns mycket sparsamt i kvinnornas och männens data, att de återfanns då och då i de unga männens data och att de unga kvinnorna var de som använde dessa språkdrag mest frekvent. Analys av tonläge i användarkommentarerna visade att män oftast använde en aggressiv eller neutral ton, medan kvinnor, unga kvinnor och unga män oftast använde en vänskaplig eller neutral ton. Unga kvinnor använde en aggressiv ton oftare än kvinnor och unga män. Utöver detta visade resultatet att ellips av subjekt och/eller predikatsverb var mest frekvent i de unga männens användarkommentarer, följt av kvinnornas, de unga kvinnornas och männens. Sammandragna former användes näst intill undantagslöst i hela korpusen. Eftersom pojkarna uppvisade mest frekvent användning av ellips av subjekt och/eller predikatsverb samt använde sammandragna former i full utsträckning, kan slutsatsen dras att de unga männens syntax är mer påverkad av engelskt talspråk än syntaxen hos de tre andra kommenterande grupperna.

This thesis investigates how to reach and recruit cutting-edge users to user experience studies. The recruitment of cutting-edge users is difficult since these users usually are not registered in recruitment databases. Cutting-edge users are advanced, early-adopters of technology and sometimes referred to as opinion leaders. Telecom research projects performed at Ericsson Research involve products and services 2-3 years ahead of the market; early-adopters and cutting edge users are therefore an important user group.   To test recruitment methods a user experience study was performed of Ericsson Labs developer portal. Ericsson Labs offers Application Programming Interfaces for mobile and web applications development. Internet marketing theories were used to form a recruitment method. Respondents were recruited from the Ericsson Labs user database and they were contacted individually via email. The users were invited to share their thoughts and ideas about the portal to help improve and possibly influence the direction of the site.   This thesis also assessed different online qualitative research methods applied for user experience research. Online focus groups such as bulletin boards were used to interact with users in addition to individual chat and voice interviews. Performing user experience research on the Internet is a cost-efficient way to interact with users in geographically dispersed areas.   The findings from the study show that recruitment is hard; it is especially difficult to recruit active and conversational respondents from a user database. Providing incentives and using personal communication were shown to be successful strategies to convince users to participate in a study.

[ An abstract in English will follow] Denna uppsats handlar om på vilket sätt användarinvolvering påverkar acceptansen av ett affärssystem. I studien redogörs varför acceptansen påverkas av användarinvolveringen, samt hur påverkan sker och vad som leder till den. IT genomsyrar idag så gott som alla former av företagsamhet. Affärssystem stödjer affärsprocesser i flera branscher, från tillverkande företag till renodlade tjänsteföretag. Ett företag behöver exempelvis anpassa både sina affärsprocesser och det nya affärssystem för allt som sker inom företaget. På grund av komplexiteten som detta för med sig är implementeringen ofta ett stort steg för företaget och dess anställda. De framtida användarna av systemet ställs inför en stor förändring som ett nytt affärssystem medför. För att göra övergången så enkel som möjligt och få användarna att acceptera systemet brukar användarna vara delaktiga i implementationen genom en process som benämns som användarinvolvering. Forskning inom området har enats om att användarinvolveringen påverkar acceptansen av ett system (Dickson & Simmons, 1970; Powers & Dickson, 1973; Wu, et al.,2002; Kujala, 2003;, Gable, et al., 2003; Amoako-Gyampah, 2005; Sharp, et al., 2007). Desto mindre finns skrivet om varför acceptansen påverkas av användarinvolveringen, hur den påverkas, samt vad det egentligen är i användarinvolveringen som påverkar acceptansen. Denna uppsats undersökte detta genom att en kvalitativ studie utformades. Teorin om att användarinvolveringen påverkar acceptansen kombinerades med Technology Acceptance Model (en modell för undersökning av acceptansen föreslagen av Davis, 1989) för att skapa en egenutvecklad modell. Den egenutvecklade modellen användes för att skapa teman kring vilka den öppna individuella intervjun utformades. Därefter genomfördes intervjuer med fyra användare som var involverade i en implementationsprocess. Resultatet från intervjuerna strukturerades på ett sätt som matchade teman i den egenskapade modellen. Därefter analyserades resultatet med hjälp av det teoretiska materialet som insamlades under studiens inledningsfas. Slutsatsen är att användarinvolveringen som process består av flera företeelser som tros påverka acceptansen. De företeelserna som tros ha påverkat acceptansen på företaget som studerades var: användarnas förståelse för vad som kommer krävas av dem i framtiden, utbildningen och dess kvalité, användares tidigare kunskap och förmåga att ta in ny kunskap samt företagets mål med implementationen och hur väl det nya systemet kan uppfylla dessa. Slutligen bör man inte bortse ifrån de krav som företaget ställer på sina anställda. En medarbetare kan känna sig tvungen att acceptera ett visst system, då det redan är beslutat att företaget ska bruka systemet. [English abstract] This essay covers what in the user involvement process affects user acceptance of an Enterprise Resource Planning System (ERP). The study reads up on why the acceptance is affected by user involvement, how the influence derives and where it comes from. Information Technology permeates all forms of enterprise. ERP systems support business processes for many different types of enterprise, ranging from manufacturing to service oriented. A company needs to adapt both its business processes and the new ERP system to fit the company’s business processes and support them throughout the value chain. As a result of the complexity that this adaptation implies, the implementation turns often out to be a big step for the company and its employees. Because of that, future ERP system users face a huge change in their work life. To make this easy and increase the chances of the future users to accept the new system, a process called user involvement is often used. Research has shown that user involvement affects the acceptance of a system (Dickson & Simmons, 1970; Powers & Dickson, 1973; Wu, et al.,2002; Kujala, 2003; Gable, Sedera & Chan, 2003; Amoako-Gyampah, 2005; Sharp, et al., 2007). On the contrary, less is known on why the acceptance is affected by user involvement, how the relation looks like and what in the user involvement process actually affects the acceptance. This essay studied that using a qualitative approach. By combining the theory that user involvement affects the acceptance, with the Technology Acceptance Model (a theory proposed by Davis (1989) that models how users come to accept and use a technology), a new model was developed. The self-created model was used to develop themes which were used as a base for the empirical research. Four interviews with system users took place and the result was analyzed using the theories collected in the earlier part of the study. The conclusion is that user involvement as a process contains many different parts which we believe may influence acceptance. Our study has shown that the acceptance depends on – but not limited to – the following: user’s understanding of what will be required of them in their future work, the educational process and its quality, user’s technical knowledge before the implementation process began, user’s ability to learn, as well as the company’s goals set for the implementation and to which degree the new system will fulfill these goals. Finally, the demands which the company sets on its employees must not be ignored. An employee can feel obligated towards company’s choice of the ERP system and compelled to accept the new system, because it has already been decided that the company would use it.

This paper presents the designing process of Tourist Guiding app on iPhone. This app aims for assisting tourists to schedule their trip plan in detail. The designing process consisted of three phases: research, interface design, user evaluation. In order to focus on user-centered  research, two methods were carried out questionnaire survey, interview with participants. After the research was done, the results of research were analyzed and summarized so that the potential requirements were collected. Those requirements would decide the inclusive features of this app, such as navigation,plan a trip,search for transportation.  Meanwhile, the interfaces of this app were designed on the platform: Photoshop. Lastly, the paper prototype's evaluation was conducted with four participants. The valuable feedbacks was given and the improvements of the interfaces were done.

This thesis contributes toward understanding fundamental limits of multi-user fading channels and random wireless networks. Specifically, considering different samples of channel gains corresponding to different users/nodes in a multi-user wireless system, the maximum number of channel gains supporting a minimum rate is asymptotically obtained. First, the user capacity of fading multi-user channels with minimum rates is analyzed. Three commonly used fading models, namely, Rayleigh, Rician and Nakagami are considered. For broadcast channels, a power allocation scheme is proposed to maximize the number of active receivers, for each of which, a minimum rate Rmin>0 can be achieved. Under the assumption of independent Rayleigh fading channels for different receivers, as the total number of receivers n goes to infinity, the maximum number of active receivers is shown to be arbitrarily close to ln(P.ln(n))/Rmin with probability approaching one, where P is the total transmit power. The results obtained for Rayleigh fading are extended to the cases of Rician and Nakagami fading models. Under the assumption of independent Rician fading channels for different receivers, as the total number of receivers n goes to infinity, the maximum number of active receivers is shown to be equal to ln(2P.ln(n))/Rmin with probability approaching one. For broadcast channels with Nakagami fading, the maximum number of active receivers is shown to be equal to ln(ω/μ.P.ln(n))/Rmin with probability approaching one, where ω and μ are the Nakagami distribution parameters. A by-product of the results is to also provide a power allocation strategy that maximizes the total throughput subject to the rate constraints. In multiple-access channels, the maximum number of simultaneous active transmitters (i.e. user capacity) is obtained in the many user case in which a minimum rate must be maintained for all active users. The results are presented in the form of scaling laws as the number of transmitters increases. It is shown that for all three fading distributions, the user capacity scales double logarithmically in the number of users and differs only by constants depending on the distributions. We also show that a scheduling policy that maximizes the number of simultaneous active transmitters can be implemented in a distributed fashion. Second, the maximum number of active links supporting a minimum rate is asymptotically obtained in a wireless network with an arbitrary topology. It is assumed that each source-destination pair communicates through a fading channel and destinations receive interference from all other active sources. Two scenarios are considered: 1) Small networks with multi-path fading, 2) Large Random networks with multi-path fading and path loss. In the first case, under the assumption of independent Rayleigh fading channels for different source-destination pairs, it is shown that the optimal number of active links is of the order log(N) with probability approaching one as the total number of nodes, N, tends to infinity. The achievable total throughput also scales logarithmically with the total number of links/nodes in the network. In the second case, a two-dimensional large wireless network is considered and it is assumed that nodes are Poisson distributed with a finite intensity. Under the assumption of independent multi-path fading for different source-destination pairs, it is shown that the optimal number of active links is of the order N with probability approaching one. As a result, the achievable per-node throughput obtained by multi-hop routing scales with Θ(1/√N).

Relevance assessing is an important part of information retrieval (IR) evaluation in addition to being something that all users of IR systems must do as part of their search for relevant documents. In this thesis, we present a user study conducted to understand the relevance judging behaviour of assessors when the prevalence of relevant documents in a set of documents to be judged is varied. In our user study, we collected judgements of participants on document sets of three different prevalence levels. The prevalence levels that we used were low (0.1), balanced (0.5) and high (0.9). We found that participants who judged documents at the 0.9 level made the most mistakes, and participants who judged documents at the 0.5 level made the least mistakes. We did not find a statistically significant difference in judging quality between 0.1 and 0.5 prevalence levels.

Syftet för uppsatsen var att undersöka om klienter med tidigare narkotikaberoende upplever att de har möjlighet till inflytande inom vården som de tar del av. Syftet var även att ta reda på hur socialarbetare inom samma vårdprogram arbetar för att möjliggöra brukarinflytandet för klienterna. Vi utförde semistrukturerade intervjuer med fem klienter och två socialarbetare från samma behandlingshem. De teoretiska perspektiv som stod till grund för analysen av empirin var brukarinflytande och demokrati. Resultatet visar att klienterna upplevde stor delaktighet inom vårdprogrammet samt i kontakten med socialarbetarna på behandlingshemmet. Vidare visar resultatet att socialarbetarna arbetar utifrån deltagardemokrati då klienterna ständigt uppmuntras till att tänka självständigt, planera, fatta egna beslut och sätta upp mål för både behandlingen och inför framtiden. De begränsande faktorerna för brukarinflytande ansågs bland annat vara ekonomi, oengagerade socialarbetare samt skilda arbetssätt mellan kommunerna. Brukarinflytande inom missbruksvården kan gynna behandlingsresultaten och förebygga återfall då klienten får vara delaktig och påverka vårdens innehåll. Brukarinflytande kan leda till goda klient- och socialarbetarrelationer och detta kan även bidra till att allt fler individer med beroendeproblematik frivilligt söker hjälp. / The purpose of this study was to examine whether clients with former drug addiction feel that they are able to influence the care that they receive. The aim was also to find out how social workers operate to enable user influence amongst clients. We conducted semi-structured interviews with five clients and two social workers within one treatment home. The theoretical perspectives that were used to analyze the empirical data were user influence and democracy. The results show that clients experience significant involvement in their care-program and in relation to social workers at the treatment home. The results also show that the social workers apply democracy to their work since they constantly encourage clients to think independently, make their own decisions and set goals for the future. The limiting factors of user influence were considered to be financial questions, unengaged social workers, and different work procedures among municipalities. Since clients become involved and are able to influence the content of the care, user influence within addiction care is believed to benefit patient outcomes and prevent relapse. User influence can lead to positive social worker-client relationships and encourage individuals with addiction to voluntarily seek care.

Electronic medical records (EMR) and computerized provider order entry (CPOE) are recognized as a means to improve quality of care and patient safety. This research examines factors that contribute to clinician acceptance of an EMR implemented in a pediatric hospital system and applies this knowledge to improve implementation methods to ensure they foster acceptance. A framework for User-Centered Implementation (UCI) was developed based on previous EMR and CPOE, technology acceptance, user-centered design, and change management research. The UCI framework identifies tools from change management and user-centered design and links them to the systems development lifecycle stage(s) at which they can be applied to achieve improved user acceptance. Next, a study examined clinician EMR acceptance in a pediatric hospital system at various points during their EMR implementation which employed a UCI-based methodology. Surveys before and after implementation of each phase examined physician, nurse, and other staff perceptions about the systems usefulness (performance expectancy (PE)) and ease of use (effort expectancy (EE)). Results indicate users had positive perceptions of system ease of use (EE) after implementation. Post-implementation PE ratings were neutral or positive for most users. Pre- and post-implementation regression models indicate the factors that influence PE change over time. Compatibility with clinician work practices was important both before and after implementation. Before implementation, users who perceived a greater need for the system and felt their needs were represented during design had higher expectations of system usefulness. After implementation, system characteristics including how well it supports clinical decision making and how easy it is to use influenced PE. Support provided by super users positively influenced both PE and EE after implementation. Based on these findings, guidelines for using UCI to improve clinician acceptance of EMR are presented. Designing EMR systems that are usable within the clinical work context enables clinicians to focus on the patient, rather than the system. Accomplishing this in practice is difficult given the complexity of EMRs and the dynamic clinical processes they support. This studys results indicate the UCI framework can be effectively applied to EMR implementations to improve the usability, utility, and, consequently, acceptance of these systems.

Management information system department has long been considered as a supporting function in organization and develop the system which should fulfill users¡¦ need to support the business process. Although previous studies indicate users participate in project process can enhance the project outcome, the final ISD project failure rate is still high and extra costs and time occurs consequently. Based on internal service concept adopted from marketing filed, this study views MIS department is viewed as an internal service provider and end user is viewed as a customer in development stage. We attempt to understand the antecedents and consequence of user co-production in ISD project. Project outcomes are expected to be affected by user co-production, represented by open communication, shared problem solving, involvement in project governance, tolerance, accommodation, advocacy and personal dedication. Project outcome is evaluated by user satisfaction, system quality and project performance. Besides, this study adopted social capital theory and examined how co-production is affected by social capitals between users and developers. Paired data collected from both user representatives and developers through using survey approach was used to test proposed hypotheses. The results showed that user co-production has positively significant influence on project outcomes, and social capitals between user representatives and developers also have positively significant influence on user co-production. Discussion of the results and conclusions about this study were made. Finally, the study also provides some academic and practical implications