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The transfer of historically grown monolithic software architectures into modern service-oriented architectures creates a lot of loose coupling points. This can lead to an unforeseen system behavior and can significantly impede those continuous modernization processes, since it is not clear where bottlenecks in a system arise. It is therefore necessary to monitor such modernization processes with an adaptive monitoring concept in order to be able to correctly record and interpret unpredictable system dynamics. For this purpose, a general measurement methodology and a specific implementation concept are presented in this work.
A Look at Service Meshes
(2021)
Service meshes can be seen as an infrastructure layer for microservice-based applications that are specifically suited for distributed application architectures. It is the goal to introduce the concept of service meshes and its use for microservices with the example of an open source service mesh called Istio. This paper gives an introduction into the service mesh concept and its relation to microservices. It also gives an overview of selected features provided by Istio as relevant to the above concept and provides a small sample setup that demonstrates the core features.
The Gravitational Search Algorithm is a swarm-based optimization metaheuristic that has been successfully applied to many problems. However, to date little analytical work has been done on this topic.
This paper performs a mathematical analysis of the formulae underlying the Gravitational Search Algorithm. From this analysis, it derives key properties of the algorithm's expected behavior and recommendations for parameter selection. It then confirms through empirical examination that these recommendations are sound.
Intrusion detection systems and other network security components detect security-relevant events based on policies consisting of rules. If an event turns out as a false alarm, the corresponding policy has to be adjusted in order to reduce the number of false positives. Modified policies, however, need to be tested before going into productive use. We present a visual analysis tool for the evaluation of security events and related policies which integrates data from different sources using the IF-MAP specification and provides a “what-if” simulation for testing modified policies on past network dynamics. In this paper, we will describe the design and outcome of a user study that will help us to evaluate our visual analysis tool.
This Innovative Practice Full Paper presents our learnings of the process to perform a Master of Science class with eduScrum integrating real world problems as projects. We prepared, performed, and evaluated an agile educational concept for the new Master of Science program Digital Transformation organized and provided by the department of business computing at the University of Applied Sciences and Arts - Hochschule Hannover in Germany. The course deals with innovative methodologies of agile project management and is attended by 25 students. We performed the class due the summer term in 2019 and 2020 as a teaching pair. The eduScrum method has been used in different educational contexts, including higher education. During the approach preparation, we decided to use challenges, problems, or questions from the industry. Thus, we acquired four companies and prepared in coordination with them dedicated project descriptions. Each project description was refined in the form of a backlog (list of requirements). We divided the class into four eduScrum teams, one team for each project. The subdivision of the class was done randomly.
Since we wanted to integrate realistic projects into industry partners’ implementation, we decided to adapt the eduScrum approach. The eduScrum teams were challenged with different projects, e.g., analyzing a dedicated phenomenon in a real project or creating a theoretical model for a company’s new project management approach. We present our experiences of the whole process to prepare, perform and evaluate an agile educational approach combined with projects from practice. We found, that the students value the agile method using real world problems. However, the results are mainly based on the summer term 2019, this paper also includes our learnings from virtual distance teaching during the Covid 19 pandemic in summer term 2020. The paper contributes to the distribution of methods for higher education teaching in the classroom and distance learning.
Die Covid-19 Pandemie hat zu einem signifikanten Anstieg der Remote Work geführt. Die Veränderung in der Interaktion und Kollaboration ist für viele agile Teams eine Herausforderung gewesen. Diverse Studien zeigen unterschiedliche Effekte und Auswirkungen auf die Zusammenarbeit agiler Teams während der Pandemie. So ist die Kommunikation sachlicher und zielgerichteter geworden. Ebenso wird eine Verminderung des sozialen Austauschs in den Teams berichtet. Unser Artikel thematisiert die Veränderung der Interaktion in agilen Teams durch die Remote Work. Wir haben eine qualitative Fallstudie bei einem agilen Software-Entwicklungsteam bei Otto durchgeführt. Unsere Ergebnisse zeigen einen Zusammenhang zwischen den Auswirkungen auf die Interaktion und der persönlichen Autonomie der Team-Mitglieder. Darüber hinaus haben wir keine signifikanten negativen Effekte durch die veränderte Interaktion auf die agile Arbeitsweise festgestellt.
Smart Cities require reliable means for managing installations that offer essential services to the citizens. In this paper we focus on the problem of evacuation of smart buildings in case of emergencies. In particular, we present an abstract architecture for situation-aware evacuation guidance systems in smart buildings, describe its key modules in detail, and provide some concrete examples of its structure and dynamics.
During the Corona-Pandemic, information (e.g. from the analysis of balance sheets and payment behavior) traditionally used for corporate credit risk analysis became less valuable because it represents only past circumstances. Therefore, the use of currently published data from social media platforms, which have shown to contain valuable information regarding the financial stability of companies, should be evaluated. In this data e. g. additional information from disappointed employees or customers can be present. In order to analyze in how far this data can improve the information base for corporate credit risk assessment, Twitter data regarding the ten greatest insolvencies of German companies in 2020 and solvent counterparts is analyzed in this paper. The results from t-tests show, that sentiment before the insolvencies is significantly worse than in the comparison group which is in alignment with previously conducted research endeavors. Furthermore, companies can be classified as prospectively solvent or insolvent with up to 70% accuracy by applying the k-nearest-neighbor algorithm to monthly aggregated sentiment scores. No significant differences in the number of Tweets for both groups can be proven, which is in contrast to findings from studies which were conducted before the Corona-Pandemic. The results can be utilized by practitioners and scientists in order to improve decision support systems in the domain of corporate credit risk analysis. From a scientific point of view, the results show, that the information asymmetry between lenders and borrowers in credit relationships, which are principals and agents according to the principal-agent-theory, can be reduced based on user generated content from social media platforms. In future studies, it should be evaluated in how far the data can be integrated in established processes for credit decision making. Furthermore, additional social media platforms as well as samples of companies should be analyzed. Lastly, the authenticity of user generated contend should be taken into account in order to ensure, that credit decisions rely on truthful information only.
The usage of microservices promises a lot of benefits concerning scalability and maintainability, rewriting large monoliths is however not always possible. Especially in scientific projects, pure microservice architectures are therefore not feasible in every project. We propose the utilization of microservice principles for the construction of microsimulations for urban transport. We present a prototypical architecture for the connection of MATSim and AnyLogic, two widely used simulation tools in the context of urban transport simulation. The proposed system combines the two tools into a singular tool supporting civil engineers in decision making on innovative urban transport concepts.
The automated transfer of flight logbook information from aircrafts into aircraft maintenance systems leads to reduced ground and maintenance time and is thus desirable from an economical point of view. Until recently, flight logbooks have not been managed electronically in aircrafts or at least the data transfer from aircraft to ground maintenance system has been executed manually. Latest aircraft types such as the Airbus A380 or the Boeing 787 do support an electronic logbook and thus make an automated transfer possible. A generic flight logbook transfer system must deal with different data formats on the input side – due to different aircraft makes and models – as well as different, distributed aircraft maintenance systems for different airlines as aircraft operators. This article contributes the concept and top level distributed system architecture of such a generic system for automated flight log data transfer. It has been developed within a joint industry and applied research project. The architecture has already been successfully evaluated in a prototypical implementation.
Automatisierte Steuerung von virtuellen Biogas-Kraftwerksverbünden für den netzorientierten Betrieb
(2019)
Das Steuerungssystem VKV Netz ermöglicht den auf die Erbringung regionaler Systemdienstleistungen ausgerichteten Betrieb virtueller Biogas-Kraftwerksverbünde. Damit leistet es sowohl einen Beitrag zum zukünftig gesteigerten Bedarf an Regelenergie durch regenerative Kraftwerke als es auch alternative, zukunftsfähige Erlöspotenziale für die zumeist landwirtschaftlichen bzw. landwirtschaftsnahen Biogas-Anlagenbetreiber abseits des EEG aufzeigt. Das Steuerungssystem wurde im Rahmen des BMWi-Verbundforschungsvorhabens VKV Netz (Förderkennzeichen 0325943A) durch die Hochschule Hannover, die SLT-Technologies GmbH & Co. KG sowie die Überlandwerk Leinetal GmbH in Kooperation mit assoziierten Biogasanlagen im Zeitraum 01.01.2016 bis 31.12.2018 entwickelt und pilotiert.
Das ProFormA-Aufgabenformat wurde eingeführt, um den Austausch von Programmieraufgaben zwischen beliebigen Autobewertern (Grader) zu ermöglichen. Ein Autobewerter führt im ProFormA-Aufgabenformat spezifizierte „Tests“ sequentiell aus, um ein vom Studierenden eingereichtes Programm zu prüfen. Für die Strukturierung und Darstellung der Testergebnisse existiert derzeit kein graderübergreifender Standard. Wir schlagen eine Erweiterung des ProFormA-Aufgabenformats um eine Hierarchie von Bewertungsaspekten vor, die nach didaktischen Aspekten gruppiert ist und entsprechende Testausführungen referenziert. Die Erweiterung wurde in Graja umgesetzt, einem Autobewerter für Java-Programme. Je nach gewünschter Detaillierung der Bewertungsaspekte sind Testausführungen in Teilausführungen aufzubrechen. Wir illustrieren unseren Vorschlag mit den Testwerkzeugen Compiler, dynamischer Softwaretest, statische Analyse sowie unter Einsatz menschlicher Bewerter.
BYOD Bring Your Own Device
(2013)
Using modern devices like smartphones and tablets offers a wide variety of advantages; this has made them very popular as consumer devices in private life. Using them in the workplace is also popular. However, who wants to carry around and handle two devices; one for personal use, and one for work-related tasks? That is why “dual use”, using one single device for private and business applications, may represent a proper solution. The result is “Bring Your Own Device,” or BYOD, which describes the circumstance in which users make their own personal devices available for company use. For companies, this brings some opportunities and risks. We describe and discuss organizational issues, technical approaches, and solutions.
Cloud Computing: Serverless
(2021)
A serverless architecture is a new approach to offering services over the Internet. It combines BaaS (Backend-as-a-service) and FaaS (Function-as-a-service). With the serverless architecture no own or rented infrastructures are needed anymore. In addition, the company does not have to worry about scaling any longer, as this happens automatically and immediately. Furthermore, there is no need any longer for maintenance work on the servers, as this is completely taken over by the provider. Administrators are also no longer needed for the same reason. Finally, many ready-made functions are offered, with which the development effort can be reduced. As a result, the serverless architecture is very well suited to many application scenarios, and it can save considerable costs (server costs, maintenance costs, personnel costs, electricity costs, etc.). The company only must subdivide the source code of the application and upload it to the provider’s server. The rest is done by the provider.
In this paper we describe the selection of a modern build automation tool for an industry research partner of ours, namely an insurance company. Build automation has become increasingly important over the years. Today, build automation became one of the central concepts in topics such as cloud native development based on microservices and DevOps. Since more and more products for build automation have entered the market and existing tools have changed their functional scope, there is nowadays a large number of tools on the market that differ greatly in their functional scope. Based on requirements from our partner company, a build server analysis was conducted. This paper presents our analysis requirements, a detailed look at one of the examined tools and a summarizes our comparison of all three tools from our final comparison round.
With an increasing complexity and scale, sufficient evaluation of Information Systems (IS) becomes a challenging and difficult task. Simulation modeling has proven as suitable and efficient methodology for evaluating IS and IS artifacts, presupposed it meets certain quality demands. However, existing research on simulation modeling quality solely focuses on quality in terms of accuracy and credibility, disregarding the role of additional quality aspects. Therefore, this paper proposes two design artifacts in order to ensure a holistic quality view on simulation quality. First, associated literature is reviewed in order to extract relevant quality factors in the context of simulation modeling, which can be used to evaluate the overall quality of a simulated solution before, during or after a given project. Secondly, the deduced quality factors are integrated in a quality assessment framework to provide structural guidance on the quality assessment procedure for simulation. In line with a Design Science Research (DSR) approach, we demonstrate the eligibility of both design artifacts by means of prototyping as well as an example case. Moreover, the assessment framework is evaluated and iteratively adjusted with the help of expert feedback.
In microservice architectures, data is often hold redundantly to create an overall resilient system. Although the synchronization of this data proposes a significant challenge, not much research has been done on this topic yet. This paper shows four general approaches for assuring consistency among services and demonstrates how to identify the best solution for a given architecture. For this, a microservice architecture, which implements the functionality of a mainframe-based legacy system from the insurance industry, serves as an example.
Since textual user generated content from social media platforms contains valuable information for decision support and especially corporate credit risk analysis, automated approaches for text classification such as the application of sentiment dictionaries and machine learning algorithms have received great attention in recent user generated content based research endeavors. While machine learning algorithms require individual training data sets for varying sources, sentiment dictionaries can be applied to texts immediately, whereby domain specific dictionaries attain better results than domain independent word lists. We evaluate by means of a literature review how sentiment dictionaries can be constructed for specific domains and languages. Then, we construct nine versions of German sentiment dictionaries relying on a process model which we developed based on the literature review. We apply the dictionaries to a manually classified German language data set from Twitter in which hints for financial (in)stability of companies have been proven. Based on their classification accuracy, we rank the dictionaries and verify their ranking by utilizing Mc Nemar’s test for significance. Our results indicate, that the significantly best dictionary is based on the German language dictionary SentiWortschatz and an extension approach by use of the lexical-semantic database GermaNet. It achieves a classification accuracy of 59,19 % in the underlying three-case-scenario, in which the Tweets are labelled as negative, neutral or positive. A random classification would attain an accuracy of 33,3 % in the same scenario and hence, automated coding by use of the sentiment dictionaries can lead to a reduction of manual efforts. Our process model can be adopted by other researchers when constructing sentiment dictionaries for various domains and languages. Furthermore, our established dictionaries can be used by practitioners especially in the domain of corporate credit risk analysis for automated text classification which has been conducted manually to a great extent up to today.
Digitale Marktplätze können die Kosten einer Handelstransaktion, die sog. Transaktionskosten, senken. Durch weiteren technischen Fortschritt und intelligente Handelsbots wird die Nutzung des Marktmechanismus immer kostengünstiger. Dieser Artikel gibt einen Überblick über die bisherige Entwicklung von Digitalen Marktplätzen der Agrar- und Ernährungswirtschaft und eine mögliche Zukunft. Vermutlich werden die Transaktionskosten weiter fallen, sodass weitere Effizienzgewinne durch die vermehrte Nutzung von Märkten möglich sein werden.