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Modeling ETL for Web Usage Analysis and Further Improvements of the Web Usage Analysis Process
(2006)
Currently, many organizations are trying to capitalize on the Web channel by integrating the Internet in their corporate strategies to respond to their customers’ wishes and demands more precisely. New technological options boost customer relationships and improve their chances in winning over the customer. The Web channel provides for truly duplex communications between organizations and their customers and at the same time, provides the technical means to capture these communications entirely and in great detail. Web usage analysis (WUA) holds the key to evaluating the volumes of behavioral customer data collected in the Web channel and offers immense opportunities to create direct added value for customers. By employing it to tailor products and services, organizations gain an essential potential competitive edge in light of the tough competitive situation in the Web. However, WUA cannot be deployed offhand, that is, a collection of commercial and noncommercial tools, programming libraries, and proprietary extensions is required to analyze the collected data and to deploy analytical findings. This dissertation proposes the WUSAN framework for WUA, which not only addresses the drawbacks and weaknesses of state-of-theart WUA tools, but also adopts the standards and best practices proven useful for this domain, including a data warehousing approach. One process is often underestimated in this context: Getting the volumes of data into the data warehouse. Not only must the collected data be cleansed, they must also be transformed to turn them into an applicable, purposeful data basis for Web usage analysis. This process is referred to as the extract, transform, load (ETL) process for WUA. Hence, this dissertation centers on modeling the ETL process with a powerful, yet realizable model – the logical object-oriented relational data storage model, referred to as the LOORDSM. This is introduced as a clearly structured mathematical data and transformation model conforming to the Common Warehouse Meta-Model. It provides consistent, uniform ETL modeling, which eventually supports the automation of the analytical activities. The LOORDSM significantly simplifies the overall WUA process by easing modeling ETL, a sub-process of the WUA process and an indispensable instrument for deploying electronic customer relationship management (ECRM) activities in the Web channel. Moreover, the LOORDSM fosters the creation of an automated closed loop in concrete applications such as a recommendation engine. Within the scope of this dissertation, the LOORDSM has been implemented and made operational for practical and research projects. Therefore, WUSAN, the container for the LOORDSM, and the LOORDSM itself can be regarded as enablers for future research activities in WUA, electronic commerce, and ECRM, as they significantly lower the preprocessing hurdle – a necessary step prior to any analysis activities – as yet an impediment to further research interactions.
Revenue management has proven successful in service industries. This dissertation tries to answer the question if revenue management can also be applied successfully to manufacturing companies. For this purpose, a survey was conducted which showed that there is significant potential for revenue management in the steel, aluminium and paper industries. Furthermore, a number of mathematical decision models were developed and solved by heuristic procedures which showed that revenue management can improve profits for manufacturing companies substantially.
The purpose of this research study is to analyse the state of the religious tourism product in Jordan from three main perspectives: To present the current state of religious tourism in Jordan through studying the tourism movement in the holy sites and analysing the potentials and future prospects. The relationship between the local community and these sites will be the second perspective from which the researcher will form the study. A third perspective is studying the visitors’ satisfaction about the services presented to them and the evaluation of the current state of the selected holy sites, whether they are Islamic or Christian. The study was carried out at the Islamic and Christian sites of Jordan: five Christian holy sites and eight Islamic holy sites. The selection of these sites was based on their religious and tourist significance, both Islamic and Christian. The researcher obtained data by implementing different tools of study and research; most data depend on national and international statistics, indices of tourism and religious tourism in particular. The researcher’s observations were a significant tool in this study and he made valuable observations that could play an important role in developing the religious tourism product in the kingdom if they are well implemented. The researcher conducted very fruitful qualitative research (interviews) with officials working in the field of tourism and, in particular, religious tourism, and he did a lot of interviews with visitors, tourists, and pilgrims at the holy sites, local communities around the holy sites, directors of the holy sites, directors of tourism directorates and religious men (Imams or priests). 211 self-completed questionnaires were filled during the study period (from the beginning of May to the end of August 2009) to analyse religious tourism at the sites from many different perspectives. The questionnaires were analysed with the programme SPSS 17.0, and the interviews were analysed with the help of the programme MAXQDA 10. In other words, the researcher used both qualitative and quantitative methods of research. The overall target of the study was to find answers to the central question whether religious tourism is or can be used as a tool which may help to bring Muslims and Christians in Jordan closer together through a deeper understanding of their common religious heritage. One of the main and important results was about the main aim which shows that the vast majority of those who responded to the questionnaire (83.3%) believe that understanding common religious heritage is a factor upon which dialogue and a better coexistence between religions can begin to take place in a part of our world which suffers a lot of problems based on religious conflicts. Less than 1% of the respondents gave a negative answer to this question, which indicates that there are strong feelings for understanding and building relationships based on common religious heritage. This is an important finding because it reiterates the role that common religious heritage has in the promotion of religious sites and the bringing together of people from different religious backgrounds. Christians were found among the Muslims in the Islamic holy sites and vice versa; this encourages the idea of the common religious heritage and its effect on the convergence and understanding between the people of different religions. However, there is one problem and this is related to visitors from Israel, but this is because of the well-known political reasons and not due to religious beliefs of the people. Finally, on the social level and concerning intercultural and religious heritage, the researcher hopes through this project that it will contribute to develop a basis on which it is possible to bring Muslims and Christians in Jordan closer together through a deeper understanding of their common religious heritage.
The theories of design patterns and their practical implications exemplified for e-learning patterns
(2013)
Patterns are an efficient and successful way to capture best practices and access the tacit knowledge of experts. While the basic concept of patterns is simple and applicable in various domains there are many gaps in understanding the deeper meanings of the approach. This work will explore the nature of patterns and pattern languages by discussing the state-of-the-art, linking the pattern concept to its original ideas and develop a theoretical framework to understand the relations and differences between patterns in the world, patterns in our heads and pattern descriptions.
The common ground for patterns is to capture the context, problem, conflicting forces, a generative solution and the consequences in written form. To discuss the meanings of these analytical perspectives a path metaphor will be introduced in this thesis. The concepts will be linked to Alexander’s original ideas and common views from the pattern community. We will also identify gaps such as the weak understanding of the different problem levels that should be addressed in a pattern. Moreover, the thesis will reason about the quality of patterns by reflecting on wholeness and its properties.
The major contribution is the foundation of a framework that links the pattern concept to established theories from other disciplines. Patterns in the world are related to the philosophical idea of universals. A thought experiment will show the problems of abstracting and dividing a structure into parts and patterns. The construction of patterns in our heads is explained according to schema theory. Different experiences can lead to different pattern ideas. In our view the descriptions of patterns is similar to the formulation of theories. A pattern is a network of statements about the interaction of forces in a given context. Its proposed solution is supposed to resolve the existing conflict of forces. Such claims are subject to falsification and can be treated as hypotheses about good design. While good patterns are grounded on empirical cases, the generalized forms cannot be relieved from the problem of induction - what has worked in the past does not necessarily work in future cases. Patterns need to be tested continuously and evolve based on new data. From these considerations we will derive practical guidance for pattern mining.
The proposed theoretical framework will be supported by empirical findings. The lessons learnt from an authoring system that generates patterns of interactive graphics show that we can create many variations of instances based on the same universal code. This universal, however, is something artificially constructed by designers. It does not proof that this universal represents the world appropriately. To see whether individuals construct similar patterns we will report on the results from a laboratory study. The experiment tests the construction of schemas of interactive graphics. We will also reflect on pattern descriptions as the result of mining processes. Depending on the format, granularity and level of abstraction these descriptions contain different amounts of testable instructive information. A retrospective document analysis will compare different descriptions of patterns to illustrate this point.
The main contribution of this work is to show the variety of ideas about patterns, the underlying theories and relations between patterns in the world, patterns in our heads and pattern descriptions. These relations show that patterns are socially and mentally constructed. At the one hand patterns try to capture one view of the reality that can be tested empirically. On the other hand pattern descriptions also influence which artefacts are created in the future. There is a feedback loop as patterns capture a perceived reality and potentially shape parts of the future reality, i.e. new objects in the world.
Many companies use reusable containers to store and transport products. Under good conditions this can help to reduce costs and improve the ecological footprint of logistic operations. On the other hand, the acquisition, maintenance and distribution of the containers need to be organised.
The aim of this thesis is to provide mathematical models for planning transports and capacity adaptations in a container system. First, the main characteristics of this type of system and the planning tasks are analysed. A key characteristic of container transports is identified: containers can often be moved in larger quantities on the same vehicle, so that transport costs should not be regarded as linear but increasing stepwise with the number of vehicles employed. Hence, the costs represent a fixed-step function of the quantity.
It is shown that extensive literature is available concerning related topics. Mathematical models already exist, which allow for some of the facets of transport and capacity planning that are important for reusable containers. However, these approaches never cover all relevant aspects. Some are missing completely; among them the challenge to model fixed-step transportation costs.
To get a flexible, yet mathematically tractable modelling, a toolbox with two basic models and multiple add-ons was developed. These can be combined to reflect a certain application. The first basic model considers linear transport costs. It can be reduced to the well investigated minimum cost flow problem which is known to be solvable in a very efficient manner. To consider fixed-step transport costs, another basic model was proposed. This is a more complex mixed integer program. It can be solved by a tailored branch-and-cut approach, which combines the positive characteristics of a heuristic and an exact solution algorithm: it provides a reasonable and feasible solution quickly and reaches the optimum solution in the end. The model add-ons include the aspects of lost orders, delayed deliveries and take-along transports as well as two capacity measures, namely purchase and disposal of containers as well as leasing. All of these extensions can be integrated into both basic models, still preserving their mathematical characteristics.
The Tarim River, located along the northern and eastern borders of the Taklamakan Desert in Xinjiang, Northwest China, is about 1320 km long and thus one of the longest continental inland waterways in the world. In an undisturbed state, it is accompanied on both sides by floodplain forests of Euphrates Poplar (Populus euphratica Oliv.), also known as “Tugai Vegetation” or “Tugai Forests”. These forests form typical desert riparian forests as the so-called “Green Corridor” and prevent the two deserts, the Taklamakan and the Kuruk-Tagh, from merging together. At present, large areas that were originally P. euphratica riparian forests have disappeared, with the remaining areas in critical condition. Specifically, the greatest threats over the past few decades have been the rising water consumption in the upper and middle reaches and massive hydro-technical interventions (construction of embankments and dams) in the development of uncultivated land (including the direct clearance of forests) for cotton production. These have led to widespread destruction of the natural ecosystems, particularly in the lower reaches of the river where about 320 km of the floodplain forests are either highly degraded or dead as the result of nearly 30 years of river desiccation. As a consequence of these deteriorations, land desertification has been aggravated and has expanded in the region. Because of the challenges facing this ecosystem, restoration measures with the diversion of “Emergency Ecological Water” have been implemented in the affected areas since 2000. This new process of recovery measures needs efficient and extensive long-term monitoring. In this thesis, current restoration measures as implemented to date are presented and hydrological dynamics as a function of water diversion are analysed. The structure, distribution and health statues (referred to as “vitality”) of the dominant species Populus euphratica have been monitored by measuring Eco-morphological parameters of more than 5000 trees in two sampling sites (a 100-ha permanent plot and five random sampling plots of 50-m radii) at Arghan village in the lower reaches of the Tarim River in the Xinjiang Uyghur Autonomous Region of China. The effects of restoration measures on the revitalization of degraded trees have been analysed and assessed by using individual-based repeated measurements of the tree data. From a long-term point of view, and taking labour intensity and the high cost of tree height measurements into account, a suitable height-diameter model for obtaining the tree height (TH) of P. euphratica based on the diameter at breast-height data (DBH) has been developed and evaluated. The average annual groundwater depth within 300 m of the river channel at different transects (Yingsu, Karday, Arghan) recovered significantly after a second water diversion in 2001. The same rising trend in groundwater level was retained until 2004, started to decline until 2009, and then rose again until the end of the water diversion in 2011. The Mann-Kendall statistical trend test was applied to the mean monthly and annual groundwater depth of six groundwater wells at different distances from the river on the Arghan transect. The trend test for the whole time series period from 2003 to 2011 indicated that there was a statistically significant decreasing trend for all wells, but that from January 2010 to December 2011 the groundwater level in all wells had a statistically significant increase. With the exception of a relatively favourable groundwater depth for floodplain forests within a 150 m distance of the riverbed, the groundwater depth at larger distances remained far below 5 m, causing most forest plants (with the exception of the Tamarix sp.) to suffer from water scarcity. Analyses of forest structure, distribution and health status suggested that a maximum TH of 19 m was found within 0-20 m and 100-200 m of the river. By contrast, a maximum DBH of 126 cm was found within 500-600 m of the river. Trees with a TH of over 15 m and a DBH of over 60 cm appeared sporadically. The maximum CD (crown diameter) of 16.58 cm (one tree) was found next to the river bed. There was a relatively great variation in DBH when compared to TH and other eco-morphological parameters. On average, stand structure tended to be simpler as distance from the river increased. Trees classified as healthy and good accounted for approximately 40 % of all sample trees, with slightly and highly degraded trees representing nearly 60 %. Some of the eco-morphological parameters of the trees vary differently with respect to the ecological water diversion measures. In particular, in the vertical (north-south) direction, the farther the trees are from the river, the weaker the response of ecological indicators. These parameters include: tree vitality classes (VS), crown diameter (CD), height to crown (HC), frequency of root suckers, number of young seedlings, and shoot growth, as well as newly developed crown types of P. euphratica trees. Generally, the floodplain forests within 200 m of the riverbed recovered remarkably, and those between 200 and 800 m from the river showed a medium response to the water transfer, while forests further than 800 m away from the riverbed showed lesser signs of recovery. Following the evaluation and comparison of the results from ten commonly used models by means of multiple-model performance criteria (such as asymptotic t-statistics of model parameters, standardized residuals against predicted height, the root-mean-square error (RMSE), Akaike’s information criterion (AIC), mean prediction error (ME) and mean absolute error (MAE)), Model (1): TH=1.3+a/(1+b×e^(-c×DBH)) and Model (6): TH=1.3+DBH^2/(a+b×DBH+c×DBH^2) are recommended as suitable choices for approximating the height-diameter relationship of P. euphratica. The limitations of the other models, resulting in poor performance for predicting TH accurately, are also discussed.
The main objective of the conducted research was to learn and broaden the boundaries of our knowledge in regard to regional cluster policy making. Particularly the interest was in the influence of clusters and cluster policy on the pattern of economic development in the region. From the reviewed theories (Classical, Keynesian, Export-based, Neo-classical, Endogenous, New Economic Geography, Growth-pole, Location, Central place, Institutional) the factors influencing economic growth were extracted and discussed. Within these different approaches it was claimed that clusters, defined as agglomerations of firms and other related institutions in a particular sector which not only show close physical proximity but also collaborate and herewith, building an economy based on clusters, can strengthen its overall competitiveness, innovativeness and lead to economic growth. Under certain favorable conditions clusters develop and grow naturally. At the same time the growth of these economic structures can also be stimulated from the side by cluster policy. As these policies were implemented, they were showing different results, which increased the interest in the analysis of cluster based policies, its types and effects on the territorial development. Within such a vast research on cluster policy the research opportunities in 1) The character and influence of cluster policy making/ management on the economic performance and clusters and 2) Extending such research areas as: long term evolution of cluster policy, policies embeddedness in territorial context, systematization of policy recommendations setting the overall research question on how to build cluster policy leading to economic development, specifically focusing on long-term evolution of cluster policy development, the components of effective cluster policy making and its implications on the regional economic development. The above research questions were addressed while referring to following the qualitative approach by the application of the multiple (two) case study method. We follow the replication approach to multiple case study by exploring our research question in similar contexts and herewith strengthen the justification of our findings. The following two regions were selected: The Basque Country, an autonomous community in Spain, and Upper Austria, a federal state in Austria. As a result of the performed research study we have gathered valuable and in-depth information on clusters and cluster policies in the regions. Through this we enriched the knowledge on cluster policy from both a theoretical and a practical perspective.
This doctoral thesis explores a paradigm of sustainable land use in the oases along the Tarim River of northwest China, where a fragile, semi-arid riparian ecosystem is being deteriorated by excessive land and water use for agriculture, in particular for the growing of cotton. This situation poses a grave threat not only to the natural Tugai vegetation in the area but also to the long-term sustainability of the region.
We explore the hypothesis that the species Apocynum pictum may act as a sustainable crop substitute for the region, thereby replacing the water-demanding and widely distributed cash crop, cotton. This idea is motivated by the former having a lower water demand, as well as a number of other traditional and modern uses. To substantiate this hypothesis, a multidisciplinary research scheme has been designed, permitting the analyses of both the ecological and socio-economic potentials of this plant, its potential benefits relative to cotton and a comprehensive analysis of its productivity, water demand and economic potentials. This analysis is divided into three distinct sections.
Biomass and nutrient analysis: Field investigations were conducted to sample biomass and map the spatial distribution of Apocynum pictum (abbreviated as A. pictum) at five selected sites. At each site, 3-5 plots were randomly selected and the point center quarter method, as outlined by Mueller-Dombois and Ellenberg (1974), was applied for biomass sampling. Concurrently, soil profiles were dug at each site so as to obtain soil samples from the various layers and electrical conductivity was measured as a mean of investigating soil salinity. These steps are essential for determining the physical and production basis for alternative land-use considerations.
The results obtained show that the total above-ground biomass ranges from 0.6 t/ha (Qongaral 1) to 1.25 t/ha (Xayar 1), and that the total below-ground biomass of A. pictum is at 11.25 ± 5.41 t/ha. The biomass of A. pictum, relatively moderate when compared to other steppe and desert ecosystems, reflects strains of soil and water conditions for plant growth in desert margins.
Evapotranspiration and water budget: Evapotranspiration (ET) is a key component of water balance and is closely linked to ecosystem productivity. Climate parameters were measured with mobile climate stations to calculate reference crop evapotranspiration (ET0) via the Penman-Monteith equation. Diurnal foliar transpiration and conductance were measured with a porometer to calculate canopy resistance. Leaf samples were photographed and analyzed for the leaf area index (LAI) in the study area so as to calculate crop evapotranspiration under standard conditions (ETc) and crop factors (Kc). Finally, the water consumptions of A. pictum and cotton were calculated and compared so as to identify which is better suited for dry environments.
The results show that cotton in this study attained a high yield compared to the world average, and at a rather low ETc. Among the three plants tested, A. pictum required the least amount of water during the vegetation season with 217.2 mm a year, while the Chinese red date came close second with 339 mm and cotton was least water-efficient with 524.7 mm, thus demonstrating the viability of A. pictum as an alternative with significant water-saving potential.
Economic analysis: Purposive sampling was used, with relevant participants in the study being approached by flow population and snowballing or chain sampling methods. The desired information was then obtained via a structured-questionnaire survey. Three natural resource management types of Apocynum were identified and a cost-revenue analysis was carried out for each.
The results show that all three types of institutional arrangements – open access, ranching and farming – are present in our study and at various levels. Apocynum costs 1083.35 Yuan/mu, generates 3267.63 Yuan/mu of revenue from raw materials and brings a profit of 2184 Yuan/mu – the highest among of all three cash crops compared.
We conclude that A. pictum offers opportunities for the restoration of vegetation in riparian ecosystems on salinized sites under the arid conditions of the Tarim Basin, while also serving as a viable land-use alternative to cotton for cash crop agriculture, as it may generate a certain income in the form of tea and fibers, as well as fodder for livestock.
Tourism studies have understood tourism as a “Western” phenomenon, which tended to neglect the presence of “non-Western” tourists and to over-generalise the application and universality of their theories. By now, tourism has become a global phenomenon with growing numbers of “emergent tourists”, especially from China. However, its quantitative importance, the touristic performances of this source market, and especially those of Chinese outbound organized mass tourists in western tourism stages continue to be under-researched. Moreover, the analysis of the Chinese outbound tourism phenomena encompasses mostly economic and business driven-studies and reports, which look for homogeneity instead of plurality of voices.
Drawing from all of the above, the aim of this interdisciplinary research is, therefore, to explore and provide further understanding of the tourism performances of Chinese outbound organized mass tourists on German tourism stages. To achieve this, the research draws on the performance approach in tourism research.
The research is based on a phenomenological approach. Part of the study’s field research was conducted largely from 2011 to 2012, both in China and Germany. In China, information was gathered by using open and semi-structured in-depth expert interviews with representatives from the Chinese tourism industry, tourism boards, as well as with tourism academics. In Germany, the ethnographic fieldwork consisted of participant observations, semi-structured interviews and short questionnaires to Chinese outbound tourist members of group package tours organized by Chinese-German travel companies. Furthermore, expert interviews were conducted with German industry representatives, experts and academics in 2013. As far as the analysis of the field research is concerned, the study relies on the GABEK qualitative method of research analysis supported by the WinRelan 32 software.
As part of the discussion, this research argues that the examination of tourism practices and behaviours of Chinese outbound organized mass tourists under the performance metaphor is able to provide further understanding on the previously neglected tourism consumption of “non-Western” tourists. Within the findings, it was possible to identify both modern und post-modern characteristics of the Chinese outbound organized mass market. This concurs with the recent de-differentiation between the typical tourism binaries (everyday-holiday and home-away) found in tourism theory by acknowledging that everyday conventions and habits inform touristic performances of Chinese tourists in Germany. Moreover, the research presents insights that allow to corroborate the future presence of organized mass tourists in the Chinese outbound market, as well as to de-inferiorise and de–homogenise the segment. With regard to German stages, the research highlights the opportunities and challenges Germany´s tourism industry still has ahead of it. Finally, the study presents a number of implications for future practice, which can be useful to plan a long-term strategy for Chinese outbound tourism.
This dissertation consists of three articles that point out new perspectives on private equity and leverage buyouts, and enrich the current state of research through considerable efforts to better understand how private equity is creating value and how macroeconomic conditions affect the debt side:
1. Ilg, Daniel. Long-Run Relationship between Default Rates and Macroeconomic Variables in the US Leveraged Loan Market. The Journal of Fixed Income 24, no. 3 (2015): 64-76; http://www.iijournals.com/doi/abs/10.3905/jfi.2014.24.3.064 oder http://dx.doi.org/10.3905/jfi.2014.24.3.064
2. Ilg, Daniel. Value Creation Drivers in Large Leveraged Buyouts (June 18, 2015); http://ssrn.com/abstract=2621525
3. Ilg, Daniel. Firm-Specific Triggers of LBO Defaults (April 22, 2015); http://ssrn.com/abstract=2619821 or http://dx.doi.org/10.2139/ssrn.2619821
The first article deals with the influence of macroeconomic changes on the default rates of private equity loans. It identifies significant variables which have strong and significant predictive power on the LBO default rates in the U.S. market.
The second article, deals with the value creation levers which investors use to create value in their portfolio companies. This research casts light on the impact of the holding period, the effects of divesting activities and expectations about the future shape of the economy on the performance of deals.
The third article deals with firm-specific triggers of LBO defaults. Asset liquidation potential as an additional source of cash flow available for servicing debt, the valuation of the investment, the strength of the negotiated covenants, the pressure of the target's refinancing need, and the stage of the fund's life cycle.