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Technical products have become more than practical tools to us. Mobile phones, for example, are a constant companion in daily life. Besides purely pragmatic tasks, they fulfill psychological needs such as relatedness, stimulation, competence, popularity, or security. Their potential for the mediation of positive experience makes interactive products a rich source of pleasure. Research acknowledged this: in parallel to the hedonic/utilitarian model in consumer research, Human-Computer Interaction (HCI) researchers broadened their focus from mere task-fulfillment (i.e., the pragmatic) to a holistic view, encompassing a product's ability for need-fulfillment and positive experience (i.e., the hedonic). Accordingly, many theoretical models of User Experience (UX) acknowledge both dimensions as equally important determinants of a product's appeal: pragmatic attributes (e.g., usability) as well as hedonic attributes (e.g., beauty). In choice situations, however, people often overemphasize the pragmatic, and fail to acknowledge the hedonic. This phenomenon may be explained by justification. Due to their need for justification, people attend to the justifiability of hedonic and pragmatic attributes rather than to their impact on experience. Given that pragmatic attributes directly contribute to task-fulfillment, they are far easier to justify than hedonic attributes. People may then choose the pragmatic over the hedonic, despite a true preference for the hedonic. This can be considered a dilemma, since people choose what is easy to justify and not what they enjoy the most. The present thesis presents a systematic exploration of the notion of a hedonic dilemma in the context of interactive products.
A first set of four studies explored the assumed phenomenon. Study 1 (N = 422) revealed a reluctance to pay for a hedonic attribute compared to a pragmatic attribute. Study 2 (N = 134) demonstrated that people (secretly) prefer a more hedonic product, but justify their choice by spurious pragmatic advantages. Study 3 (N = 118) confronted participants with a trade-off between hedonic and pragmatic quality. Even though the prospect of receiving a hedonic product was related to more positive affect, participants predominantly chose the pragmatic, especially those with a high need for justification. This correlation between product choice and perceived need for justification lent further support to the notion that justification lies at the heart of the dilemma. Study 4 (N = 125) explored affective consequences and justifications provided for hedonic and pragmatic choice. Data on positive affect suggested a true preference for the hedonic - even among those who chose the pragmatic product.
A second set of three studies tested different ways to reduce the dilemma by manipulating justification. Manipulations referred to the justifiability of attributes as well as the general need for justification. Study 5 (N = 129) enhanced the respective justifiability of hedonic and pragmatic choice by ambiguous product information, which could be interpreted according to latent preferences. As expected, enhanced justifiability led to an increase in hedonic but not in pragmatic choice. Study 6 (N = 178) manipulated the justifiability of hedonic choice through product information provided by a "test report", which suggested hedonic attributes as legitimate. Again, hedonic choice increased with increased justifiability. Study 7 (N = 133) reduced the general need for justification by framing a purchase as gratification. A significant positive effect of the gratification frame on purchase rates occurred for a hedonic but not for a pragmatic product.
Altogether, the present studies revealed a desire for hedonic attributes, even in interactive products, which often are still understood as purely pragmatic "tools". But precisely because of this predominance of pragmatic quality, people may hesitate to give in to their desire for hedonic quality in interactive products - at least, as long as they feel a need for justification. The present findings provide an enhanced understanding of the complex consequences of hedonic and pragmatic attributes, and indicate a general necessity to expand the scope of User Experience research to the moment of product choice. Limitations of the present studies, implications for future research as well as practical implications for design and marketing are discussed.
Nandi forests (South and North Nandi forests) are situated in the Rift Valley Province of Kenya very close to Kakamega forest. From previous documents it has been seen that Kakamega and Nandi forests were connected to each other forming one big "U" shaped forest block till the beginnings of 1900s. Due to human pressures, currently there are three different forests form the previous one block forest. Although they were one forest, information on Nandi forests is very scanty when it is compared to that of Kakamega forest. The species composition and diversity as well as plant communities and population structure of Nandi forests have not been studied. Information is not available about the similarity status of South and North Nandi forests. Furthermore the natural regeneration potential (seedling bank) of these forests is not well studied and documented. Hence this study aims to fill these gaps.
In this study totally 76 quadrates (49 from South Nandi and 27 from North Nandi) were used to collect data. In the South Nandi forests 27 of the quadrates were laid in the better side of the forest (at Kobujoi) and the remaining 22 were in the heavily disturbed part of this forest (Bonjoge). The quadrates were arranged on transects that have one to one and half km which were parallel to the slope. The distance between the quadrates was 100 meter and transects are 500 m apart. The size of the main quadrate was 400 m2 (20 X 20 m) which also had five small plots (3 X 3 m) distributed on the four corners and in the center. Each woody plants (climbers, shrubs and trees) having more than one meter and greater than two centimeter diameter at breast height (dbh) were measured and recorded. Seedlings and herbaceous plants were sampled in the smaller plots. Individual plants were identified at species level and when it was not possible to identify in the field voucher specimen were prepared and latter identified at the East African Herbarium, National Museum of Kenya, and Nairobi. Clustering and ordination were performed using PC-ORD and CANOCO ecological softwares, respectively. For both clustering and ordination abundance data of the species was used. Shannon diversity index and evenness were computed using PC-ORD while similarity indices, Fisher alpha, rarefaction, species richness estimation (nonparametric species richness estimators) were conducted using EstimateS. Indicator species analysis was undertaken using PC-ORD. Basal area and height class distribution at forests level or site level (Bonjoge and Kobujoi) and diameter (dbh) class distribution for selected trees species were performed to evaluate population structure.
Furthermore importance value (IV) of woody plant species was calculated. SPSS version 16 was used to undertake both parametric (when data assume normal distribution) and nonparametric (when data are not assuming normal distribution) comparison of means, correlation and regression analysis.
In this study totally 321 vascular plant species comprising 92 families and 243 genera were identified in Nandi forests (both South and North Nandi forests). In South Nandi forest 253 plant species form 82 families and 201 genera were recorded while in North Nandi 181 species comprising 67 families and 155 genera were recorded. Jackknife second order estimators gave the highest species richness estimate for both South and North Nandi forests i.e. 284 and 209, respectively. In the case of highly disturbed and less disturbed parts of South Nandi forest 138 and 172 vascular plant species were recorded, respectively. Asteraceae, Rubiaceae and Euphorbiaceae are the top three species rich families of Nandi forests. In terms of different diversity measures (i.e. alpha and beta diversity, Fisher alpha, Shannon diversity and evenness indices) South Nandi is more diverse than North Nandi forest. Sörensen and Jaccard (classic) as well as their respective abundance based similarities showed that there is a low species similarity between South and Nandi forests. The cluster analysis resulted in three different plant communities and this result is supported by the ordination result.
South and North Nandi forest has inverted "J" height class distribution showing that larger proportion of woody plant individuals are found in the lower height classes. Similar pattern is observed when the diameters of all woody plants were considered together. However, different diameter class distributions (seven types) were identified when selected tree species were analyzed separately. It has been observed that the basal area of South Nandi forest is significantly lower than that of North Nandi forest (Mann-Whitney U =358, p < 0.001). Similarly Bonjoge has significantly lower basal area (t-value=3.77, p<0.01) than that of Kobujoi. Number of woody plat seedlings in South Nandi forest is significantly higher than that of North Nandi (Mann-Whitney U = 362.5, p<0.001). In the same way Bonjoge has significantly smaller number of ssedlings than Kobujoi (t-value 4.24, p<0.001). Most of species in both forests are able to resprout from stumps after physical damage; hence this helps the regeneration of the forests in addition to seedling banks. This study enables to fill some of the information gaps about Nandi forests especially of floristic composition, population structure, natural regeneration and human impacts on this ecosystem.
Modern Internet and Intranet techniques, such as Web services and virtualization, facilitate the distributed processing of data providing improved flexibility. The gain in flexibility also incurs disadvantages. Integrated workflows forward and distribute data between departments and across organizations. The data may be affected by privacy laws, contracts, or intellectual property rights. Under such circumstances of flexible cooperations between organizations, accounting for the processing of data and restricting actions performed on the data may be legally and contractually required. In the Internet and Intranet, monitoring mechanisms provide means for observing and auditing the processing of data, while policy languages constitute a mechanism for specifying restrictions and obligations.
In this thesis, we present our contributions to these fields by providing improvements for auditing and restricting the data processing in distributed environments. We define formal qualities of auditing methods used in distributed environments. Based on these qualities, we provide a novel monitoring solution supporting a data-centric view on the distributed data processing. We present a solution for provenance-aware policies and a formal specification of obligations offering a procedure to decide whether obligatory processing steps can be met in the future.