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Architecture for platform- and hardware-independent mesh networks : how to unify the channels
(2013)
This paper will prove that mesh networks among different platforms and hardware channels can help to channel valuable information even if public telecommunication infrastructure is not available due to arbitrary reasons. Therefore, results of a simulation for mesh networks on mass events will be provided, followed by the developed architecture and an outlook on future research. The developed architecture is currently being implemented and field tested on mass events.
Die Nutzung von Prozessmodellierungsmethoden oder - werkzeugen kann erheblichen Einfluss auf die Effektivität von Prozessen haben. Das gilt insbesondere für Situationen, in denen Personen unter Stress stehen oder ungeübt sind. In diesen Fällen geben Prozessmodelle konkrete Empfehlungen, nach denen sich die handelnden Personen richten könnten. In Experimenten mit der Business-Simulation Apollo 13 haben wir den Effekt eines Einsatzes von Prozessmodellierungsmethoden und -werkzeugen untersucht. Bereits bekannte Theorien (z.B. über geeignete Verhältnisse von Kommunikationsinhalten) konnten bestätigt werden. Darüber hinaus haben wir eine besondere Bedeutung der Übertragbarkeit von Prozessmodellen in konkrete Handlungen identifiziert.
The problem of fair and privacy-preserving ordered set reconciliation arises in a variety of applications like auctions, e-voting, and appointment reconciliation. While several multi-party protocols have been proposed that solve this problem in the semi-honest model, there are no multi-party protocols that are secure in the malicious model so far. In this paper, we close this gap. Our newly proposed protocols are shown to be secure in the malicious model based on a variety of novel non-interactive zero-knowledge-proofs. We describe the implementation of our protocols and evaluate their performance in comparison to protocols solving the problem in the semi-honest case.
The understanding that optimized components do not automatically lead to energy-efficient systems sets the attention from the single component on the entire technical system. At TU Darmstadt, a new field of research named Technical Operations Research (TOR) has its origin. It combines mathematical and technical know-how for the optimal design of technical systems. We illustrate our optimization approach in a case study for the design of a ventilation system with the ambition to minimize the energy consumption for a temporal distribution of diverse load demands. By combining scaling laws with our optimization methods we find the optimal combination of fans and show the advantage of the use of multiple fans.
Finding a good system topology with more than a handful of components is a
highly non-trivial task. The system needs to be able to fulfil all expected load cases, but at the
same time the components should interact in an energy-efficient way. An example for a system
design problem is the layout of the drinking water supply of a residential building. It may be
reasonable to choose a design of spatially distributed pumps which are connected by pipes in at
least two dimensions. This leads to a large variety of possible system topologies. To solve such
problems in a reasonable time frame, the nonlinear technical characteristics must be modelled
as simple as possible, while still achieving a sufficiently good representation of reality. The
aim of this paper is to compare the speed and reliability of a selection of leading mathematical
programming solvers on a set of varying model formulations. This gives us empirical evidence
on what combinations of model formulations and solver packages are the means of choice with the current state of the art.
Zur Unterstützung des Transformationsbedarfs von Telekommunikationsunternehmen sind die Referenzmodelle des TM Forums in der Praxis weltweit anerkannt. Dabei findet jedoch meist eine losgelöste Nutzung für spezifische Einzelthemen statt. Daher führt dieser Artikel die bestehenden Inhalte in einer industriespezifischen, übergreifenden Referenzarchitektur zusammen. Der Fokus liegt auf den Ebenen Aufbauorganisation, Prozesse, Applikationen und Daten. Darüber hinaus werden inhaltliche Architekturdomänen zur Strukturierung angeboten. Die Referenzarchitektur ist hierarchisch aufgebaut und wird hier beispielhaft für ausgewählte, aggregierte Inhalte beschrieben. Als erste Evaluation wird die Anwendung der Referenzarchitektur in drei Praxisprojekten erläutert.
Development of a subject-oriented reference process model for the telecommunications industry
(2016)
Generally the usage of reference models can be structured top-down or bottom-up. The practical need of agile change and flexible organizational implementation requires a consistent mapping to an operational level. In this context, well-established reference process models are typically structured top-down. The subject-oriented Business Process Management (sBPM) offers a modeling concept that is structured bottom-up and concentrates on the process actors on an
operational level. This paper applies sBPM to the enhanced Telecom Operations Map (eTOM), a well-accepted reference process model in the telecommunications industry. The resulting design artifact is a concrete example for a combination of a bottom-up and top-down developed reference model. The results are evaluated and confirmed in practical context through the involvement of the industry body TMForum.
Competence Developing Games (CDGs) are a new concept of how to think about games with serious intentions. In order to emphasize on this topic, a new framework has been developed. It basically relies on learning and motivation theories. This ‘motivational Competence Developing Game Framework’ demonstrates how it is possible to use these theories in a CDG development process. The theoretical derivation and use of the framework is explained in this paper.
ICSs (Industrial Control Systems) and its subset SCADA systems (Supervisory Control and Data Acquisition) are getting exposed to a constant stream of new threats. The increasing importance of IT security in ICS requires viable methods to assess the security of ICS, its individual components, and its protocols. This paper presents a security analysis with focus on the communication protocols of a single PLC (Programmable Logic Controller). The PLC, a Beckhoff CX2020, is examined and new vulnerabilities of the system are revealed. Based on these findings recommendations are made to improve security of the Beckhoff system and its protocols.
Control mechanisms like Industrial Controls Systems (ICS) and its subgroup SCADA (Supervisory Control and Data Acquisition) are a prerequisite to automate industrial processes. While protection of ICS on process management level is relatively straightforward – well known office IT security mechanisms can be used – protection on field bus level is harder to achieve as there are real-time and production requirements like 24x7 to consider. One option to improve security on field bus level is to introduce controls that help to detect and to react on attacks. This paper introduces an initial set of intrusion detection mechanisms for the field bus protocol EtherCAT. To this end existing Ethernet attack vectors including packet injection and man-in-the-middle attacks are tested in an EtherCAT environment, where they could interrupt the EtherCAT network and may even cause physical damage. Based on the signatures of such attacks, a preprocessor and new rule options are defined for the open source intrusion detection system Snort demonstrating the general feasibility of intrusion detection on field bus level.
Energy-efficient components do not automatically lead to energy-efficient systems. Technical Operations Research (TOR) shifts the focus from the single component to the system as a whole and finds its optimal topology and operating strategy simultaneously. In previous works, we provided a preselected construction kit of suitable components for the algorithm. This approach may give rise to a combinatorial explosion if the preselection cannot be cut down to a reasonable number by human intuition. To reduce the number of discrete decisions, we integrate laws derived from similarity theory into the optimization model. Since the physical characteristics of a production series are similar, it can be described by affinity and scaling laws. Making use of these laws, our construction kit can be modeled more efficiently: Instead of a preselection of components, it now encompasses whole model ranges. This allows us to significantly increase the number of possible set-ups in our model. In this paper, we present how to embed this new formulation into a mixed-integer program and assess the run time via benchmarks. We present our approach on the example of a ventilation system design problem.
In times of planned obsolescence the demand for sustainability keeps growing. Ideally, a technical system is highly reliable, without failures and down times due to fast wear of single components. At the same time, maintenance should preferably be limited to pre-defined time intervals. Dispersion of load between multiple components can increase a system’s reliability and thus its availability inbetween maintenance points. However, this also results in higher investment costs and additional efforts due to higher complexity. Given a specific load profile and resulting wear of components, it is often unclear which system structure is the optimal one. Technical Operations Research (TOR) finds an optimal structure balancing availability and effort. We present our approach by designing a hydrostatic transmission system.
Momentan finden in vielen Branchen umfassende Veränderungen von Märkten und Wertschöpfungsketten statt, welche auch als Digitale Transformation bezeichnet werden. In diesem Zusammenhang wird das Internet der Dinge (Internet of Things, IoT) als ein wichtiger technischer Enabler der Veränderungen angesehen. Primäre Ziele des IoT sind die Steuerung physischer Gegen-stände aus der Distanz und das Erfassen von Informationen aus dem Umfeld dieser Gegenstände. Welche neuen Geschäfts-bzw. Partnermodelle entstehen durch die gemeinsame Nutzung von IoT-Daten und Big-Data-Technologien und welcher qualitative Mehrwert wird dadurch geschaffen? Als Antwort wird in diesem Beitrag ein Bewertungsrahmen zur qualitativen Wertschöpfungsanalyse von IoT vorgeschlagen. Anhand dieses Bewertungsrahmens wird ein Anwendungsfall untersucht, der in anonymisierter Form an konkrete Praxisprojekte angelehnt ist. Konkret wird ein Anwendungsfall betrachtet, der eine Abfallwirtschaft 2.0 basierend auf dem Einsatz von IoT vorschlägt. Aus den Untersuchungsergebnissen gehen beispielsweise Erkenntnisse hervor, wie Geschäftsmodelle auf Basis eines unentgeltlichen Informationsaustauschs durch IoT gestaltet werden können.
Kritische Infrastrukturen sind primäre Ziele krimineller Hacker. Der Deutsche Bundestag reagierte darauf am 25. Juli 2015 mit einem Gesetz zur Verbesserung der Sicherheit von ITSystemen, dem IT-Sicherheitsgesetz. Dies verlangt von Betreibern kritischer Infrastrukturen, angemessene Mindeststandards für organisatorische und technische Sicherheit zu implementieren, um den Betrieb und die Verfügbarkeit dieser Infrastruktur zu gewährleisten. Telekommunikationsunternehmen sind einerseits von diesem Gesetz in besonderem Maße betroffen und verfügen andererseits mit dem Rahmenwerk enhanced Telecom Operations Map (eTOM) über ein international anerkanntes Referenzmodell zur Gestaltung von Geschäftsprozessen in dieser Branche. Da sämtliche Telekommunikationsunternehmen in Deutschland verpflichtet sind, das Gesetz innerhalb eines bestimmten Zeitrahmens zu implementieren, präsentiert dieser Beitrag einen Vorschlag zur Erweiterung von eTOM um die relevanten Anforderungen des deutschen IT-Sicherheitsgesetzes.
Primäre Ziele des Internets der Dinge sind die Steuerung physischer Gegenstände aus der Distanz und das Erfassen von Informationen aus dem Umfeld dieser Gegenstände. Dazu werden Hardwarekomponenten in Gegenstände des täglichen Lebens und die Umwelt integriert. Mithilfe von Informations- und Kommunikationstechnologien entsteht hieraus das Internet der Dinge (Internet of Things, IoT). Vor einem Jahr wurde mit Narrowband Internet of Things (NB-IoT) eine Technologie die es ermöglicht, Hardwarekomponenten energieeffizient und unmittelbar über das Mobilfunknetz zu vernetzen. Gegenstände werden dadurch über große Reichweiten eigenständig kommunikationsfähig. Das IoT steht mit NB-IoT vor einem gestiegenen Nutzenpotenzial, da eine zunehmende Anzahl miteinander verbundener Gegenstände und der Austausch größerer Datenmengen realisierbar sind. Damit sind aus wirtschaftlicher Sicht neue, innovative Anwendungsfälle des IoT möglich, die auch bereits in der Praxis diskutiert werden. In diesem Beitrag wird anhand eines konkreten Anwendungsfalls untersucht, welche neuen Geschäfts- bzw. Partnermodelle durch die gemeinsame Nutzung von NB-IoT-Daten und Big Data-Technologien entstehen und welcher qualitative Mehrwert für die an einem Anwendungsfall beteiligten Stakeholder geschaffen wird. Dazu wird – einem konstruktionsorientierten Forschungsansatz folgend – ein Bewertungsrahmen zur qualitativen Wertschöpfungsanalyse von NB-IoT entwickelt, der u.a. auf der Schablone nach Cockburn und dem Business Model Canvas basiert. Anhand dieses Bewertungsrahmens wird ein Anwendungsfall untersucht, der in anonymisierter Form an konkrete Praxisprojekte angelehnt ist. Konkret wird ein Anwendungsfall betrachtet, der einen Fahrradverleih 2.0 basierend auf dem Einsatz von NB-IoT vorschlägt. Aus den Untersuchungsergebnissen gehen beispielsweise Erkenntnisse hervor, wie Geschäftsmodelle auf
The telecommunications industry is currently going through a major transformation. In this context, the enhanced Telecom Operations Map (eTOM) is a domain-specific process reference model that is offered by the industry organization TM Forum. In practice, eTOM is well accepted and confirmed as de facto standard. It provides process definitions and process flows on different levels of detail. This article discusses the reference modeling of eTOM, i.e., the design, the resulting artifact, and its evaluation based on three project cases. The application of eTOM in three projects illustrates the design approach and concrete models on strategic and operational levels. The article follows the Design Science Research (DSR) paradigm. It contributes with concrete design artifacts to the transformational needs of the telecommunications industry and offers lessons-learned from a general DSR perspective.
This paper introduces a hardware setup to measure efficiency maps of low-power electric motors and their associated inverters. Here, the power of the device under test (DUT) ranges from some Watts to a few hundred Watts. The torque and speed of the DUT are measured independent of voltage and current in multiple load points. A Matlab-based software approach in combination with an open Texas-Instruments (TI) hardware setup ensures flexibility. Exemplarily, the efficiency field of a Permanent Magnet Synchronous Machine (PMSM) is measured to proof the concept. Brushless-DC (BLDC) motors can be tested as well. The nomenclature in this paper is based on the new European standard DIN EN 50598. Special attention is paid to the calculation of the measurement error.
Nowadays, the most employed devices for recoding videos or capturing images are undoubtedly the smartphones. Our work investigates the application of source camera identification on mobile phones. We present a dataset entirely collected by mobile phones. The dataset contains both still images and videos collected by 67 different smartphones. Part of the images consists in photos of uniform backgrounds, especially collected for the computation of the RSPN. Identifying the source camera given a video is particularly challenging due to the strong video compression. The experiments reported in this paper, show the large variation in performance when testing an highly accurate technique on still images and videos.
Es existieren verschiedenste Arten von Spielen, die versuchen, die Motivation einer Spielsituation in einen ernsten Kontext zu überführen. In diesem Artikel wird der Überbegriff „Competence Developing Games“ definiert und anhand von Beispielen erläutert. Dafür werden Erkennungskriterien vorgestellt, entsprechende Spieltypen erläutert und eine Zuordnung durch-geführt.
Motivation-based Learning: Teaching Fundamentals of Electrical Engineering with an LED Spinning Top
(2018)
To increase pressure to supply all floors of high buildings with water, booster stations, normally consisting of several parallel pumps in the basement, are used. In this work, we demonstrate the potential of a decentralized pump topology regarding energy savings in water supply systems of skyscrapers. We present an approach, based on Mixed-Integer Nonlinear Programming, that allows to choose an optimal network topology and optimal pumps from a predefined construction kit comprising different pump types. Using domain-specific scaling laws and Latin Hypercube Sampling, we generate different input sets of pump types and compare their impact on the efficiency and cost of the total system design. As a realistic application example, we consider a hotel building with 325 rooms, 12 floors and up to four pressure zones.
The overall energy efficiency of ventilation systems can be improved by considering not only single components, but by considering as well the interplay between every part of the system. With the help of the method "TOR" ("Technical Operations Research"), which was developed at the Chair of Fluid Systems at TU Darmstadt, it is possible to improve the energy efficiency of the whole system by considering all possible design choices programmatically. We show the ability of this systematic design approach with a ventilation system for buildings as a use case example.
Based on a Mixed-Integer Nonlinear Program (MINLP) we model the ventilation system. We use binary variables to model the selection of different pipe diameters. Multiple fans are model with the help of scaling laws. The whole system is represented by a graph, where the edges represent the pipes and fans and the nodes represents the source of air for cooling and the sinks, that have to be cooled. At the beginning, the human designer chooses a construction kit of different suitable fans and pipes of different diameters and different load cases. These boundary conditions define a variety of different possible system topologies. It is not possible to consider all topologies by hand. With the help of state of the art solvers, on the other side, it is possible to solve this MINLP.
Next to this, we also consider the effects of malfunctions in different components. Therefore, we show a first approach to measure the resilience of the shown example use case. Further, we compare the conventional approach with designs that are more resilient. These more resilient designs are derived by extending the before mentioned model with further constraints, that consider explicitly the resilience of the overall system. We show that it is possible to design resilient systems with this method already in the early design stage and compare the energy efficiency and resilience of these different system designs.
The UN sets the goal to ensure access to water and sanitation for all people by 2030. To address this goal, we present a multidisciplinary approach for designing water supply networks for slums in large cities by applying mathematical optimization. The problem is modeled as a mixed-integer linear problem (MILP) aiming to find a network describing the optimal supply infrastructure. To illustrate the approach, we apply it on a small slum cluster in Dhaka, Bangladesh.
The continuing growth of scientific publications raises the question how research processes can be digitalized and thus realized more productively. Especially in information technology fields, research practice is characterized by a rapidly growing volume of publications. For the search process various information systems exist. However, the analysis of the published content is still a highly manual task. Therefore, we propose a text analytics system that allows a fully digitalized analysis of literature sources. We have realized a prototype by using EBSCO Discovery Service in combination with IBM Watson Explorer and demonstrated the results in real-life research projects. Potential addressees are research institutions, consulting firms, and decision-makers in politics and business practice.
Angesichts des anhaltenden Wachstums wissenschaftlicher Veröffentlichungen werden Instrumente benötigt, um Literaturanalysen durch Digitalisierung produktiver zu gestalten. Dieser Beitrag stellt einen Ansatz vor, der bibliographische Daten aus der Literaturdatenbank EBSCO Discovery Service mithilfe von Text-Analytics-Methoden erschließt. Die Lösung basiert auf dem Textanalysesystem IBM Watson Explorer und eignet sich für explorative Literaturanalysen, um beispielsweise den Status quo emergierender Technologiefelder in der Literatur zu reflektieren. Die generierten Ergebnisse sind in den Kontext der zunehmenden Werkzeugunterstützung des Literaturrechercheprozesses einzuordnen und können für intra- sowie interinstitutionelle Wissenstransferprozesse in Forschungs- und Beratungskontexten genutzt werden.
This paper introduces a Competence Developing Game (CDG) for the purpose of a cybersecurity awareness training for businesses. The target audience will be discussed in detail to understand their requirements. It will be explained why and how a mix of business simulation and serious game meets these stakeholder requirements. It will be shown that a tablet and touchscreen based approach is the most suitable solution. In addition, an empirical study will be briefly presented. The study was carried out to examine how an interaction system for a 3D-tablet based CDG has to be designed, to be manageable for non-game experienced employees. Furthermore, it will be explained which serious content is necessary for a Cybersecurity awareness training CDG and how this content is wrapped in the game
During the development of a Competence Developing Game’s (CDG) story it is indispensable to understand the target audience. Thereby, CDGs stories represent more than just the plot. The Story is about the
Setting, the Characters and the Plot. As a toolkit to support the
development of such a story, this paper introduces the UserFocused Storybuilding (short UFoS) Framework for CDGs. The Framework and its utilization will be explained, followed by a description of its development and derivation, including an empirical study. In addition, to simplify the Framework use regarding the CDG’s target audience, a new concept of Nine Psychographic Player Types will be explained. This concept of Player Types provides an approach to handle the differences in between players during the UFoS Framework use. Thereby,
this article presents a unique approach to the development of
target group-differentiated CDGs stories.
Phase Repeatable Synthesizers as a New Harmonic Phase Standard for Nonlinear Network Analysis
(2018)
In diesem Paper wird die Entwicklung und Evaluation eines grafischen Regeleditors für das Erstellen von „Smart Living Environments“-Services vorgestellt. Dafür werden zunächst die Deduktion und Implementierung des grafischen Regeleditors erläutert. Anschließend wird eine Probandenstudie vorgestellt, in welcher der Mehrwert bezogen auf die Aspekte Zeit, Fehleranfälligkeit und Gebrauchstauglichkeit festgestellt wird.
MedicVR : Acceleration and Enhancement Techniques for Direct Volume Rendering in Virtual Reality
(2019)
Water suppliers are faced with the great challenge of achieving high-quality and, at the same time, low-cost water supply. In practice, the focus is set on the most beneficial maintenance measures and/or capacity adaptations of existing water distribution systems (WDS). Since climatic and demographic influences will pose further challenges in the future, the resilience enhancement of WDS, i.e. the enhancement of their capability to withstand and recover from disturbances, has been in particular focus recently. To assess the resilience of WDS, metrics based on graph theory have been proposed. In this study, a promising approach is applied to assess the resilience of the WDS for a district in a major German City. The conducted analysis provides insight into the process of actively influencing the
resilience of WDS
The paper industry is the industry with the third highest energy consumption in the European Union. Using recycled paper instead of fresh fibers for papermaking is less energy consuming and saves resources. However, adhesive contaminants in recycled paper are particularly problematic since they reduce the quality of the resulting paper-product. To remove as many contaminants and at the same time obtain as many valuable fibres as possible, fine screening systems, consisting of multiple interconnected pressure screens, are used. Choosing the best configuration is a non-trivial task: The screens can be interconnected in several ways, and suitable screen designs as well as operational parameters have to be selected. Additionally, one has to face conflicting objectives. In this paper, we present an approach for the multi-criteria optimization of pressure screen systems based on Mixed-Integer Nonlinear Programming. We specifically focus on a clear representation of the trade-off between different objectives.