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For aiding computer security experts in their study, log files are a crucial piece of information. Especially the time domain is very important for us because in most cases, timestamps are the only linking points between events caused by attackers, faulty systems or simple errors and their corresponding entries in log files. With the idea of storing and analyzing this log information in graph databases, we need a suitable model to store and connect timestamps and their events. This paper aims to find and evaluate different approaches how to store timestamps in graph databases and their individual benefits and drawbacks.

We analyse three different approaches, how timestamp information can be represented and stored in graph databases. For checking the models, we set up four typical questions that are important for log file analysis and tested them for each of the models. During the evaluation, we used the performance and other properties as metrics, how suitable each of the models is for representing the log files’ timestamp information. In the last part, we try to improve one promising looking model.

We come to the conclusion, that the simplest model with the least graph database-specific concepts in use is also the one yielding the simplest and fastest queries.

Limitations to this research are that only one graph database was studied and also improvements to the query engine might change future results.

In the study, we addressed the issue of storing timestamps in graph databases in a meaningful, practical and efficient way. The results can be used as a pattern for similar scenarios and applications.

Authorization and access control have been a topic of research for several decades. However, existing definitions are inconsistent and even contradicting each other. Furthermore, there are numerous access control models and even more have recently evolved to conform with the challenging requirements of resource protection. That makes it hard to classify the models and decide for an appropriate one satisfying security needs. Therefore, this study aims to guide through the plenty of access control models in the current state of the art besides this opaque accumulation of terms meaning and how they are related.

This study follows the systematic literature review approach to investigate current research regarding access control models and illustrate the findings of the conducted review. To provide a detailed understanding of the topic, this study identified the need for an additional study on the terms related to the domain of authorization and access control.

The authors’ research results in this paper are the distinction between authorization and access control with respect to definition, strategies, and models in addition to the classification schema. This study provides a comprehensive overview of existing models and an analysis according to the proposed five classes of access control models.

Based on the authors’ definitions of authorization and access control along with their related terms, i.e. authorization strategy, model and policy as well as access control model and mechanism, this study gives an overview of authorization strategies and propose a classification of access control models providing examples for each category. In contrast to other comparative studies, this study discusses more access control models, including the conventional state-of-the-art models and novel ones. This study also summarizes each of the literature works after selecting the relevant ones focusing on the database system domain or providing a survey, a classification or evaluation criteria of access control models. Additionally, the introduced categories of models are analyzed with respect to various criteria that are partly selected from the standard access control system evaluation metrics by the National Institute of Standards and Technology.

Knowledge- and communication-intensive domains still long for a better support of creativity that considers legal requirements, compliance rules and administrative tasks as well, because current systems focus either on knowledge representation or business process management. The purpose of this paper is to discuss our model of integrated knowledge and business process representation and its presentation to users.

The authors follow a design science approach in the environment of patent prosecution, which is characterized by a highly standardized, legally prescribed process and individual knowledge study. Thus, the research is based on knowledge study, BPM, graph-based knowledge representation and user interface design. The authors iteratively designed and built a model and a prototype. To evaluate the approach, the authors used analytical proof of concept, real-world test scenarios and case studies in real-world settings, where the authors conducted observations and open interviews.

The authors designed a model and implemented a prototype for evolving and storing static and dynamic aspects of knowledge. The proposed solution leverages the flexibility of a graph-based model to enable open and not only continuously developing user-centered processes but also pre-defined ones. The authors further propose a user interface concept which supports users to benefit from the richness of the model but provides sufficient guidance.

The balanced integration of the data and task perspectives distinguishes the model significantly from other approaches such as BPM or knowledge graphs. The authors further provide a sophisticated user interface design, which allows the users to effectively and efficiently use the graph-based knowledge representation in their daily study.

Data protection requirements heavily increased due to the rising awareness of data security, legal requirements and technological developments. Today, NoSQL databases are increasingly used in security-critical domains. Current survey works on databases and data security only consider authorization and access control in a very general way and do not regard most of today’s sophisticated requirements. Accordingly, the purpose of this paper is to discuss authorization and access control for relational and NoSQL database models in detail with respect to requirements and current state of the art.

This paper follows a systematic literature review approach to study authorization and access control for different database models. Starting with a research on survey works on authorization and access control in databases, the study continues with the identification and definition of advanced authorization and access control requirements, which are generally applicable to any database model. This paper then discusses and compares current database models based on these requirements.

As no survey works consider requirements for authorization and access control in different database models so far, the authors define their requirements. Furthermore, the authors discuss the current state of the art for the relational, key-value, column-oriented, document-based and graph database models in comparison to the defined requirements.

This paper focuses on authorization and access control for various database models, not concrete products. This paper identifies today’s sophisticated – yet general – requirements from the literature and compares them with research results and access control features of current products for the relational and NoSQL database models.

Throughout the past few decades a considerable philosophical literature has appeared, covering the various aspects of the history of philosophy and practically all of the systematic disciplines. Annual reports of this literature have been prepared for the past twenty years by James Collins, St. Louis University, for the Cross Currents review. These surveys are the best single source for keeping abreast of publications in the field. The collected reviews (1957–1977) are now available from Cross Currents at Dobbs Ferry, New York.

In the tourism industry the rapidly increasing environmental dynamism and the intensity of competition call for constant improvements in Services' quality and pricing. Of the various elements in the tourism Performance bundle, the environment is an important starting point for examining the possibility of strengthening competitive position. Relative weightings of individual environmental pollutants regarding their importance to travel decisions are needed as a basis for decisions about effective countermeasures. An analysis of tourism, traffic and environmental developments, as well as an attempt to evaluate the relative weightings of various environmental impacts, gave the following working hypothesis: Of the various environmental pollutants which are relevant to the tourism industry in the Austrian Alpine region, traffic pollution constitutes the most important problem. The problem was examined with an emphasis on Tyrol, but the results should be largely transferable to the neighbouring areas in South Tyrol, Switzerland and Bavaria. The working hypothesis on the one hand refers to tourism as an industry effected by environmental pollutants, which are caused by both tourism and nontourism production and consumption activities. The pollutants act as impairments on the holiday experience. On the other hand it refers to tourism as a problem causer, with external effects on the non‐tourism and tourism industry. Traffic pollution has a comparatively large influence here too. This tourism‐related causer/effected‐combination for environmental pollution is relevant at both the local and the global level in different. Locally the directly effective aesthetic pollution stands out the most, for instance in the form of noise or damage to the countryside. Globally it's the “big” environmental problems (among other things the hypothesis on global warming), where, of the environmental pollution caused by tourism, traffic pollution makes a dominant contribution. The developed working hypotheses and assumptions about the relative weightings of different tourism‐related environmental pollutants are, due to inadequate data, based on rough estimates. To support them, the working hypotheses need, above all, an improved supply of data specific to the problem, to be collected scientifically with, among other things, more social and scientific research into the subjective problem perceptions of tourists and their reactions in the holiday decision process.

The article deals with factors that act as an incentive to internationalisation of the hotels in the small‐to‐medium‐sized enterprises (SME) category in the traditional tourism countries, and also discusses the obstacles to internationalisation. The “OLI” approach according to Dunning (ownership advantages, location‐specific advantages, advantages of internalisation) is tested against the results of a survey of hotelkeepers in the Alpine countries, particularly Austria. It is not just the size of the enterprise that acts as a limit on the extent of internationalisation of SMEs. Other factors that determine the attitude taken towards internationalisation include market intelligence, financing problems, the degree of entrepreneurial spirit, and the specific nature of tourism services.

Die Überbrückung der Spannung zwischen Bedürfnissen und ihrer Befriedigung ist Aufgabe der Wirtschaft. Diese ihre Funktion ist nur dann erfüllbar, wenn die Wirtschaft bestrebt ist, diese Bedürfnisse zu erkennen, sie in ihren Motiven zu analysieren, sie zu steigern oder neue zu erwecken. Hiezu bedient sie sich der Werbung im weitesten Sinne, der Konsumforschung, der Untersuchung der Marktgegebenheilen, der Soziologie, der Betriebswirtschaft und der Technik.