Context. Social media marketing is constantly gaining interest as a powerful tool, for advertisement campaigns, in order to maximize their audience to reach potential new customers. To efficiently target customers, the knowledge of social network structure and user behavior is of crucial importance. Among these online social networks, Twitter’s popularity is rapidly increasing. Its key feature is to link different topics and posts by using the hashtag symbol. This particular characteristic is one of the principal causes that direct users to specific topics, and lead them to expand their network. Objectives. In this study we investigate a correlation between hashtags and increase of followers motivated by a specific research question. The question is whether the addition of hashtags to tweets produces new followers. Methods. We designed a controlled experiment in which we gather tweets from two types of users: users tweeting with hashtags and users tweeting without hashtags. Users tweeting with hashtags will belong to the experimental group and users tweeting without hashtags will form part of the control group. Their statistical behavior is analyzed by conducting the non-parametrical Mann-Whitney U-test. Results. The results of the Mann-Whitney U-Test show that the null hypothesis is rejected at confidence level 0.05. Based on that, a correlation is shown between hashtags and followers, therefore tweets that contain hashtags are more likely to lead to a higher increase in the number of followers than tweets without hashtags. Conclusions. This thesis contributes to describe the functionality of hahstags in the online social network Twitter. It provides an original correlational study on the use of hashtags and increase of followers. We discover that users tweeting with hashtags are more likely to increase their number of followers than users that tweet without hashtags. This discovery opens a new research direction regarding hashtags and followers, specifically to discover which hashtags increase the number of followers and which do not.

Context. Software testing is one of the crucial phases in software development life cycle (SDLC). Among the different manual testing methods in software testing, Exploratory testing (ET) uses no predefined test cases to detect defects. Objectives. The main objective of this study is to test the effectiveness of ET in detecting defects at different software test levels. The objective is achieved by formulating hypotheses, which are later tested for acceptance or rejection. Methods. Methods used in this thesis are literature review and experiment. Literature review is conducted to get in-depth knowledge on the topic of ET and to collect data relevant to ET. Experiment was performed to test hypotheses specific to the three different testing levels : unit , integration and system. Results. The experimental results showed that using ET did not find all the seeded defects at the three levels of unit, integration and system testing. The results were analyzed using statistical tests and interpreted with the help of bar graphs. Conclusions. We conclude that more research is required in generalizing the benefits of ET at different test levels. Particularly, a qualitative study to highlight factors responsible for the success and failure of ET is desirable. Also we encourage a replication of this experiment with subjects having a sound technical and domain knowledge. / H.no.2-7-644, Mukrumpura, Karimnagar, Pincode:500001, India, Phone number: +91-9908644775

Software testing is a key phase in software development lifecycle. Testing objectives corresponds to the discovery and detection of faults, which can be attained by utilizing manual or automated testing approaches. In this thesis, we are mainly concerned with the manual test approaches. The most commonly used manual testing approaches in the software industry are the Exploratory Testing (ET) approach and the Test Case Based Testing (TCBT) approach. TCBT is primarily used by software testers to formulize and guide their testing tasks and set the theoretical principles for testing. On the other hand ET is simultaneous learning, test design, and test execution. Software testing might benefit from an intelligent combination of these approaches of testing however there is no proof of any formal process that accommodates the usage of both test approaches in a combination. This thesis presents a process for Mix Testing (MT) based on the strengths and weaknesses of both test approaches, identified through a systematic literature review and interviews with testers in a software organization. The new process is defined through the mapping of weaknesses of one approach to the strengths of other. Static validation of the MT process through interviews in the software organization suggested that MT has ability to resolve the problems of both test approaches to some extent. Furthermore, MT was validated by conducting an experiment in an industrial setting. The analysis of the experimentation results indicated that MT has better defect detection than TCBT and less than ET. In addition, the results of the experiments also indicate that MT provides equal functionality coverage as compared to ET and TCBT.

The earlier in the development process a fault is found, the cheaper it is to correct the fault. Therefore are verification and validation methods important tools. The problem with this is that there are many methods to choose between. This thesis sheds light on how to choose between four common verification and validation methods. The verification and validation methods presented in this thesis are reviews, inspections and Fault Tree Analysis. Review and inspection methods are evaluated in an empirical study. The result of the study shows that there are differences in terms of defect detection. Based on this study and literature study, guidelines on how to choose the best method in a given context are given. / Desto tidigare i utvecklingsprocessen som ett fel hittas, desto billigare är det att rätt till detta fel. Därför är verifierings- och valideringsmetoder viktiga verktyg. Problemet är att det finns många metoder. Den här rapporten sprider ljus över hur man ska välja mellan fyra vanliga verifierings- och valideringsmetoder. Verifierings- och valideringsmetoderna i den här rapporten är granskningar, inspektioner och "Fault Tree Analysis". Granskningar och inspektioner är utvärderade i en empiriskt studie. Resultatet av studien visar att det finns skillnader mellan metoderna när det gäller att hitta fel.

The emerging industrial trend towards agile software development processes brings forth new concerns, challenges as well as opportunities. One of the main concerns is with respect to the achievable quality levels of the final product, for which testing is the well-known assurance mechanism. However, it is not well defined for the community on how to perform testing using existing expertise in an agile environment. This uncertainty may create confusion and contra productivity that can lead to testing teams and their practices considered as an obstacle for full implementation of agile processes within an organisation.   This thesis outlines our current research activities towards identifying and addressing important organisational and technical challenges in the agile environment.  In this context, we propose a new role for traditional testers which will enable them to integrate into the agile team as well as to fully exploit their knowledge in the new context. We have conducted an elaborate industrial survey on the preferences and practices with respect to the contemporary aspects of software testing and identified test-driven development as an important technical area for improvement.  A systematic review on empirical evidences related to test-driven development was performed subsequently, which revealed a list of factors limiting its widespread industrial acceptance. Knowledge of testing was identified as one of those factors and was further investigated in a controlled experiment performed with undergraduate students.   Our future works aim to confirm these research findings in wider as well as industrial settings and investigate other limiting factors in detail, with the aim of providing guidelines for achieving better utilisation of testers and testing practices.

SAMMANFATTNING I detta projekt har jag undersökt restprodukten glasmjöl för att ta fram nya potentiella material för designområdet. Jag har arbetat nyfiket och experimentellt för att behålla fokus och intresset vid liv, samt för att fortsätta vara kreativ trots exempelvis stress eller press. Glasmjölet har under projektet processats på olika sätt och blivit ett flertal material med olika egenskaper. Framförallt har jag valt att fokusera på en av processerna vilket var att smälta glasmjölet i 780°C. Detta material blir bland annat poröst, starkt och dekorativt samt skulle med fördel kunna gjutas i en serieproduktion, om det finns gott om restprodukten glasmjöl. Detta återkommer jag till mer under diskussionen.  Under projektet har jag inspirerats friskt av konstverk, design, starka karaktärer och uttrycket ”less is more”, där jag ställer mig kritisk till uttrycket. Två viktiga referenser för mitt arbete har varit Iris Apfel och skulpturen ”Kyssen” av Auguste Rodin som mitt designförslag är mycket inspirerat av. Skulpturen i designförslaget kommenterar uttrycken ”ornament and crime” och ”less is more” där jag istället vill att min skulptur gärna uttrycker ”more is more” där funktionen fokuserar på det dekorativa och skulpturala. Mina slutförslag är tänkta att tänja på gränser och inspirera, samt väcka intresse i syfte att intressenter kan arbeta vidare i materialet för att på sikt ta tillvara på detta avfall som resurs och därmed bidra till en mer hållbar glasindustri, samt möjligtvis även gynna glasindustrin i Sverige. Slutförslagen är också menade att utmana normer kring både estetik och tankesätt som gärna också får väcka ett intresse i sig. För att utforska mitt ämne har jag hållit en workshop, intervjuat ett flertal personer inom design, återvinning och glas. Jag har arbetat på ett intuitivt, strategiskt och konstnärligt sätt. Under projektet var det viktigt för mig att inte begränsas av min kunskap som glasblåsare utan utforska glasmjölet så öppet som möjligt. Jag har använt ohämmade och okomplicerade metoder i den experimentiella fasen som har väckt min nyfikenhet och kreativitet. Därtill har jag tagit strategiska beslut i slutfasen av projektet, för att kunna använda mig av den rika informationen jag har arbetat fram, och sedan göra genomtänkta, relevanta val. För mig har beslutet, att använda intuitionen, rättfärdigat ett sätt att tänka som fungerar bra för mig eftersom det gjorde processen lustfylld, höll mig nyfiken samt möjliggjorde ett snabbare arbetstempo. Det har fått mig att hålla intresset vid liv samt undvika stress i samband med arbetet som skulle kunna göra processen stum. Jag har genom detta förhållningssätt valt att ha alla delar av mitt liv i fokus.

Based on three essays, this Ph.D. thesis studies costly and truthful communication in the following situation: a sender (S) tries to convince a receiver (R) to accept a project.<p>Before communication, both agents do not know the project quality. On the one hand, they believe with probability α that the project is of high quality and will raise R’s payoff by r_H, and otherwise that it is of low quality and will decrease R’s payoff by / Doctorat en Sciences économiques et de gestion / info:eu-repo/semantics/nonPublished

Laborationen i skolan har länge haft en betydelsefull roll i undervisningen av de naturvetenskapliga ämnena. Det har visat sig i olika forskningsstudier att lärare har olika mål när de planerar och genomför laborationer i undervisningen men som överlag är ganska inbördes samstämmiga. Då naturkunskap har en annan karaktär än kemi, biologi och fysik så kanske resonemanget om laborationer och målet med dem har en annan innebörd i naturkunskap. Det här arbetet är inriktat på att ta reda på vilka mål som lärarna har med laborationer i naturkunskap samt vilka utmaningar som påverkar lärarna när de ska genomföra laborationer i ämnet och om de anser det motiverat att ha fler laborationer i ämnet. Undersökningen är gjord med en intervjustudie av några naturkunskapslärare på gymnasiet. Resultaten visar att det både finns likheter och skillnader när det gäller lärares mål med laborationer. Både sinsemellan, men också om man jämför med tidigare forskning för naturvetenskapliga ämnen. Det har också visat sig att gymnasielärare inte har en enhetlig definition när det kommer till vad en laboration är.  Elevgrupp och problem med att hitta bra laborationer som passar naturkunskapens samhällsinnehåll är några av de utmaningar som lärarna har för att nå målen.

We examined effects of the macroalgae Laurencia and Palisada spp. on epifauna within seagrass beds of Thalassia testudinum. First we conducted a field survey of Thalassia testudinum beds with varying densities of Laurencia and Palisada spp. Second, we conducted a field experiment, manipulating natural and simulated Laurencia and Palisada spp. In the field survey, we found that total faunal biomass (g m-2) increased significantly with Laurencia and Palisada spp. cover. In the experiment, natural Laurencia and Palisada spp. supported an increased density (No. m-2) of fauna, however, faunal values were highest in the simulated algae treatment. This suggests that the mechanism of increased density/biomass due to Laurencia and Palisada spp. is structural complexity. Since habitat quality in Thalassia testudinum beds may be mediated by associated macroalgae, these small-scale habitat factors need to be incorporated in habitat and ecosystem conservation plans.

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