Sven Hartmann

• Clausthal University of Technology

This study proposes a new approach to creating a virtual flight test environment by integrating a digital twin of an iron bird test rig with an engineering flight simulator. Generating digital twins for test rigs in aviation is a rare and innovative approach. The engineering flight simulator used in this study incorporates real hands-on throttle an...

Dynamic workflow scheduling (DWS) is a challenging and important optimization problem in cloud computing, aiming to execute multiple heterogeneous workflows on dynamically leased virtual machine resources to satisfy user-defined Quality of Service requirements. For the popular deadline-constrained DWS in cloud problem, a virtual machine selection r...

Containers are quickly gaining popularity in cloud computing environments due to their scalable and lightweight characteristics. However, the problem of Resource Allocation in Container-based clouds (RAC) is much more challenging than the Virtual Machines (VMs)-based clouds because RAC includes two levels of allocation problems: allocating containe...

Microservice is a new architecture for application development that makes applications more flexible to deploy, extend and update compared to monolithic architectures. As container-based clouds rapidly gained popularity in recent years, more microservices are deployed in containers and composed of complex and elaborated applications for users. The...

As a lightweight and flexible infrastructure solution, containers have increasingly been used for application deployment on a global scale. By rapidly scaling containers at different locations, the deployed applications can handle dynamic workloads from the worldwide user community. Existing studies usually focus on the (dynamic) container scaling...

The domain of beyond-the-visual-line-of-sight (BVLOS) flights of unmanned aerial vehicles (UAVs) has unique navigational challenges such as the reliable estimation, evaluation and mitigation of the risk of the associated flight paths. To tackle these challenges domain data from heterogeneous sources is needed. Failing to integrate this data careful...

More and more enterprises are increasingly gaining technical and economic benefits from the global cloud marketplace.

Scenario-based approaches have recently been widely adopted in the automotive and aviation industries. They aim to define and manage the test cases in a better way, thereby significantly reducing the risks and defining the safety argument for the system. To improve and complement the safety conditions, the Operational Design Domain (OOD) defines th...

Graph databases are an emerging technology with the potential to support complex data-intensive applications. Existing works on designing graph models often take an intuitive approach. In this paper, we discuss why this can easily lead to performance degradation for application-specific queries, and illustrate this with the example of dynamic taxi...

Background: Embedded feature selection in high-dimensional data with very small sample sizes requires optimized hyperparameters for the model building process. For this hyperparameter optimization, nested cross-validation must be applied to avoid a biased performance estimation. The resulting repeated training with high-dimensional data leads to ve...

Community detection in social networks is an emerging concept in the realm of artificial intelligence. It helps organizations to offer targeted services based on community predispositions. Social networks require effective community detection methods to detect clusters of users with dense inner community connections and sparse external connections....

View Video Presentation: https://doi.org/10.2514/6.2022-3629.vid The rapid development and integration of technology mean that customer needs also change rapidly. Also, this change is proceeding in the same way in every industry field. Making use of Digital Technologies is one of the biggest investments of companies to produce the best for customer...

Autonomous robots and vehicles are expected to become an integral part of our environment soon. Unsatisfactory issues (esp. for path planning) regarding interaction with existing road users, performance in mixed-traffic areas, and lack of interpretable behavior remain key obstacles. To address these, we present a physics-based neural network, based...

Autonomous robots and vehicles are expected to soon become an integral part of our environment. Unsatisfactory issues regarding interaction with existing road users, performance in mixed-traffic areas and lack of interpretable behavior remain key obstacles. To address these, we present a physics-based neural network, based on a hybrid approach comb...

Background: Embedded feature selection in high-dimensional data with very small sample sizes requires optimized hyperparameters for the model building process. For this hyperparameter optimization, nested cross-validation must be applied to avoid a biased performance estimation. The resulting repeated training with high-dimensional data leads to ve...

Web service composition composes existing web services to accommodate users’ requests for required functionalities with the best possible quality of services (QoS). Due to the computational complexity of this problem, evolutionary computation (EC) techniques have been employed to efficiently find composite services with near-optimal functional qual...

Multi-cloud makes it possible to effectively utilize various cloud services provided by multiple cloud providers at different locations. To process the requests for latency-sensitive applications, cloud brokers must select proper cloud services in multi-cloud to minimize the network latency without running into the risk of over-spending. The proble...

QoS-aware automated semantic web service composition aims to find a composite service with optimized or nearoptimized Quality of Service (QoS) and Quality of Semantic matchmaking within polynomial time. To cope with this NPhard problem with high complexity, a variety of Evolutionary Computation (EC) techniques have been developed. To improve the ef...

Embedded functional dependencies (eFDs) advance data management applications by data completeness and integrity requirements. We show that the discovery problem of eFDs is \({\mathsf {NP}}\)-complete, \(\mathsf {W}[2]\)-complete in the output, and has a minimum solution space that is larger than the maximum solution space for functional dependencie...

The rapid advancements in autonomous driving enable the formation of vehicle groups with small distances between vehicles, known as platooning. This technology has attracted research interest as it offers great benefits for future transportation, e.g., fuel economy, reduced CO\(_2\) emissions, increased road capacity and improved road safety. Previ...

Building on classical theorems of Sperner and Kruskal-Katona, we investigate antichains \(\mathcal {F}\) in the Boolean lattice Bn of all subsets of \([n]:=\{1,2,\dots ,n\}\), where \(\mathcal {F}\) is flat, meaning that it contains sets of at most two consecutive sizes, say \(\mathcal {F}=\mathcal {A}\cup {\mathscr{B}}\), where \(\mathcal {A}\) co...

The paper “Bounded Pattern Matching Using Views” was accidentally published twice in the book “Database and Expert Systems Applications, Part II”, and the paper “View Selection for Graph Pattern Matching” was omitted. This has been corrected. Each paper is now included once.

Airborne systems are becoming more and more complex, making it harder to meet the volatile requirements of complex systems or sub-systems. Test infrastructures are inevitably inheriting product complexity. Iron bird test rigs need real actuators, hydraulic pumps, piping, loading systems which make their development and operation resource intensive....

Multi-cloud is becoming a popular cloud ecosystem because it allows enterprise users to share the workload across multiple cloud service providers to achieve high-quality services with lower operation cost and higher application resilience. In multi-cloud, cloud services are widely distributed at different locations with differentiated prices. Ther...

Shared space, an emerging alternative to conventional traffic design, encourages and requires social interaction among heterogeneous traffic participants and efficient space usage by doing away with explicit road divisions and rules. However, concerns about its efficiency and safety give rise to a need for realistic simulation models. While there i...

Service-oriented architecture (SOA) is a widely adopted software engineering paradigm that encourages modular and reusable applications. One popular application of SOA is web service composition, which aims to loosely couple web services to accommodate complex goals not achievable through any individual web service. Many approaches have been propos...

We propose a conceptual framework to be utilized by developers of applications that require alternative routes in road networks. Our framework implements an efficient approach for dynamic alternative route planning that can respond to road network changes. With our framework, state-of-the-art algorithms for alternative route planning can be enabled...

Enterprise application providers are increasingly moving their workloads to the cloud for technical and economic benefits. Multi-cloud environment makes it possible to orchestrate multiple cloud resources. With the increasing number of available cloud resources provided by multiple cloud providers at different locations with different prices, appli...

The double volumes LNCS 12391-12392 constitutes the papers of the 31st International Conference on Database and Expert Systems Applications, DEXA 2020, which will be held online in September 2020. The 38 full papers presented together with 20 short papers plus 1 keynote papers in these volumes were carefully reviewed and selected from a total of 19...

The double volumes LNCS 12391-12392 constitutes the papers of the 31st International Conference on Database and Expert Systems Applications, DEXA 2020, which will be held online in September 2020. The 38 full papers presented together with 20 short papers plus 1 keynote papers in these volumes were carefully reviewed and selected from a total of 19...

With the ever increasing complexity of airborne systems, it is becoming extremely hard to identify, analyze and resolve problems during the life-cycle of aircraft. Increasing the reliability of future air vehicles designed for the airspace with rapidly growing traffic, collecting data during the system design and manufacturing phases and fetching i...

This paper proposes a Python-based infrastructure for studying the characteristics and behavior of families of systems. The infrastructure allows automatic execution of simulation experiments with varying system structures as well as with varying parameter sets in different simulators. Possible system structures and pa-rameterizations are defined u...

Web service composition aims to loosely couple web services to accommodate complex goals, which can not be accomplished by any existing web service. Many researchers have been working on such service composition problems with the aim to find composite services with optimized Quality of Service (QoS) and/or Quality of Semantic Matchmaking (QoSM). Du...

Web service composition aims to loosely couple web services to accommodate complex goals, which can not be accomplished by any existing web service. Many researchers have been working on such service composition problems with the aim to find composite services with optimized Quality of Service (QoS) and/or Quality of Semantic Matchmaking (QoSM). Du...

The emergence of more complex, data-intensive applications motivates a high demand of effective data modeling for graph databases to support efficient query answering. In this paper, we develop an intuitive graph data model for dynamic taxi ride sharing. We argue that our proposed data model meets the data needs imposed by three fundamental tasks a...

Web service composition aims to provide added values by loosely coupling web services to accommodate users' complex requirements. Evolutionary computation techniques have been used to efficiently find near-optimal composite services to satisfy users' requirements reasonably well. Often, the quality of a composite service is measured by two importan...

Nowadays, data for real world application are very complex and mostly stored with different models in distributed storage engines. Data integration becomes a challenge, as the inconsistency as well as the nonuniform access need to be handled for best integration results. The goal of this paper is to find a mechanism to integrate heterogeneous data,...

Comprehensive quality-aware automated semantic web service composition is an NP-hard problem, where service composition workflows are unknown, and comprehensive quality, i.e., Quality of services (QoS) and Quality of semantic matchmaking (QoSM) are simultaneously optimized. The objective of this problem is to find a solution with optimized or near-...

Exchanging simulation models is currently of utmost importance. To improve interoperability between suppliers and original equipment manufacturers (OEMs), the functional mock-up interface (FMI) is exchanged in a standard format called functional mock-up unit (FMU). Since its first release, many simulation tools took the initiative to support FMI. H...

Web services are basic functions of a software system to support the concept of service-oriented architecture. They are often composed together to provide added values, known as web service composition. Researchers often employ Evolutionary Computation techniques to efficiently construct composite services with near-optimized functional quality (i....

Driving trucks in a queue behind each other and in close proximity, called platooning, has been recently under consideration as a novel and promising approach to reduce fuel consumption, which provides environmental and financial benefits. This method works since driving in the slipstream of another vehicle reduces the aerodynamic drag, and as a re...

The System Entity Structure (SES) is a high level approach for variability modeling, particularly in simulation engineering. An SES describes a set of system congurations, i.e. different system structures and parameter settings of system components. In combination with a Model Base (MB), executable models can be generated from an SES. Based on an e...

Web services are basic functions of a software system to support the concept of service-oriented architecture. They are often composed together to provide added values, known as web service composition. Researchers often employ Evolutionary Computation techniques to efficiently construct composite services with near-optimized functional quality (i....

Despite the gravity of scenarios in modeling and simulation, there is a lack of common tools, formats and practices. This eventually impairs shareability and interoperability. There is a recent interest in aviation domain for the standardization of scenario definition languages. System Entity Structure (SES) is proposed as a formal approach for a st...

This two volume set of LNCS 11706 and LNCS 11707 constitutes the refereed proceedings of the 30th International Conference on Database and Expert Systems Applications, DEXA 2019, held in Linz, Austria, in August 2019. The 32 full papers presented together with 34 short papers were carefully reviewed and selected from 157 submissions. The papers are...

This two volume set of LNCS 11706 and LNCS 11707 constitutes the refereed proceedings of the 30th International Conference on Database and Expert Systems Applications, DEXA 2019, held in Linz, Austria, in August 2019.The 32 full papers presented together with 34 short papers were carefully reviewed and selected from 157 submissions. The papers are...

Even in times of a continuously growing computational power and miniaturisation of computers and control devices, the demand for model reduction techniques persists. Detailed models of physical systems typically result in rather complex dynamic models. In the design process, when the design space has been narrowed down to a concrete design, it is o...

DO-178C/ED-12C is a recent update of the industry standard that provides guidance for software considerations in airborne systems. DO-330/ED-215 has recently been developed as an annex to DO-178C/ED-12C for software tool qualification. It explains tool life-cycle processes as a part of the certification endeavor. With the advancements of model-base...

Service Oriented Architecture starts with the concept of web services, which give birth to an application of web service composition that selects and combines web services to accommodate users’ complex requirements. These requirements often cover functional parts (i.e., semantic matchmaking of services’ inputs and outputs) and non-functional parts...

Web service composition has been a challenging research area, where many researchers have been working on a composition problem that optimizes Quality of service and/or Quality of semantic matchmaking of composite solutions. This NP-hard problem has been successfully handled by many Evolutionary Computation techniques with promising results. Estima...

We present a method for extracting road network data that has been crowdsourced in the OpenStreetMap project and transform it into a road network that is stored as a graph database. We propose an algorithm for the transformation, discuss opportunities for semantic enrichment of the road network, and for restricting the transformation to geographic...

Today’s companies in high-tech industries develop products of high complexity which consist of complicated subsystems with many heterogeneous components integrated together. As the system complexity increases, it becomes increasingly more challenging to manage the tedious development process. The Capability Maturity Model Integration (CMMI) was pro...

Aeronautical informatics is an emerging cross disciplinary field of study where the computer and aircraft meet. Like many other fields of aeronautics, simulation is an essential part of aeronautical informatics education and research. Among others, low cost, high flexibility and adaptability are the key requirements for simulation infrastructures i...

Big Data technology in the field of aviation has emerged in recent years. Continuously growing amounts of data sources such as sensors, radars, cameras, weather stations, airports, etc. produce terabytes of high dynamic data each second. The future aviation concepts require modern data storing, data processing, and data analyzing technologies. The...

The history of flight started with the pioneer era. The introduction of mechanical controls (including hydraulics) then led to the second era. Later, with the utilization of computers and automation in aircraft, we reached the third era. Now, we are moving towards the fourth era of flight, namely Flight 4.0, which is characterized by “smart” and “c...

The importance of accurate intrusion detection is growing tremendously as the malicious network traffic activities have also grown significantly. Intrusion Detection Systems (IDSs) provide automatic detection for security violation like denial of service (DoS), virus, port scans, buffer overflows, CGI attacks, clogging or flooding etc. For network...

The replacement of Figure 9 in the paper named Design and Development of Research Aviation Training Device.

Though there are numerous Aviation Training Devices (ATDs) available on the market, it is still hard to find a specifically designed one for research and education purposes. Based on the requirements of researchers and students, we designed and developed a Research Aviation Training Device (RATD) for the Aeronautical Informatics Research Group at C...

Scenarios are crucial elements in a simulation study. Typical scenario management activities include scenario development, loading and parsing, distribution and role casting, event injection, and finally data collection and logging. Recently, significant effort is being spent towards standardization in simulation scenario development. A standard si...

This two volume set of LNCS 11029 and LNCS 11030 constitutes the refereed proceedings of the 29th International Conference on Database and Expert Systems Applications, DEXA 2018, held in Regensburg, Germany, in September 2018. The 35 revised full papers presented together with 40 short papers were carefully reviewed and selected from 160 submissio...

Comprehensive quality-aware semantic web service composition aims to optimise semantic matchmaking quality and Quality of service (QoS) simultaneously. It is an NP-hard problem due to its huge search space. Therefore, heuristics have to be employed to generate near-optimal solutions. Existing works employ Evolutionary Computation (EC) techniques to...

A Web service can be thought of as a software module designed to accomplish specific tasks over the Internet. Web services are very popular, as they encourage code reuse as opposed to re-implementing already existing functionality. The process of combining multiple Web services is known as Web service composition. Previous attempts at automatically...

Grouping vehicles into platoons with short distance can reduce fuel consumption up to \(21\%\) [1] and improve capacity of roads. The Vehicle Platooning Problem deals with route planing to form platoons and therefore minimize the overall costs of all considered vehicles. This article is focused on the subject to find groups with most fuel savings p...

We present an new optimisation framework combining two meta-heuristics: Genetic Algorithms (GA) and Particle Swarm Optimisation (PSO). In contrast to the usual hybridisation models in which the second algorithm is applied to work on the final results of the first one, our approach uses both algorithms in parallel on the same population in a compete...

Web service composition has been a prevailing research direction in recent years. There are two major challenges faced by researchers, semantic matchmaking and Quality of Service (QoS) optimisation. Semantic matchmaking aims to discover interoperable web services that can interact with each other by their resources described semantically. QoS optim...

A full squashed flat antichain (FSFA) in the Boolean lattice $B_n$ is a family $\mathcal{A}\cup\mathcal{B}$ of subsets of $[n]=\{1,2,\dots,n\}$ such that, for some $k\in [n]$ and $0\le m\le \binom n k$, $\mathcal{A}$ is the family of the first $m$ $k$-sets in squashed (reverse-lexicographic) order and $\mathcal{B}$ contains exactly those $(k-1)$-su...

In der Steuerungsentwicklung haben sich Entwurfsmethodiken wie der Rapid Control Prototyping (RCP) An-satz etabliert. Die Steuerungssoftware (CS) wird durchgehend modellbasiert in möglichst einer Softwareum-gebung entwickelt. Beginnend in der frühen Entwurfsphase, wird ein Simulationsmodell (SM) schrittweise zu einer CS ausgebaut. Die Überführung i...

The concept of Service-Oriented Architecture, where individual services can be combined to accomplish more complex tasks, provides a flexible and reusable approach to application development. Their composition can be performed manually, however doing so may prove to be challenging if many service alternatives with differing qualities are available....

While any simulation study starts with a scenario, scenario development is usually conducted in an unstructured and ad hoc manner. In order to streamline scenario development, a formal approach is envisioned in the research flight simulator facility of German Aerospace Center (DLR), namely Air Vehicle Simulator (AVES). System Entity Structure (SES)...

As fuel accounts for a significant proportion of the total operational cost of heavy duty vehicles (HDVs) and to alleviate the environmental impacts, companies are seeking for novel practical methods to reduce fuel consumption. Platooning is an effective approach in which a string of HDVs driving close behind each other is formed. This reduces the...

Web services have emerged as an open standard-based means for publishing and sharing data through the Internet. Whenever web services disclose sensitive data to service consumers, data privacy becomes a fundamental concern for service providers. In many applications, sensitive data may only be disclosed to particular users for specific purposes. Th...

Label propagation is a very popular, simple and fast algorithm for detecting communities in a graph such as a social network. However, it known to be non-deterministic, unstable and not very accurate. These shortcoming have attracted much attention by the research community, and many improvements have been suggested. In this paper we propose an new...

Scilab/Xcos is a graphical modeling and simulation environment for hybrid dynamic systems. It provides a graphical editor which allows representing models with block diagrams. While each block represents a computational function, links specify the data and event flow. However, as the number of the blocks and the links increases, the Xcos schema can...

Scilab is an open-source cross-platform computing environment for engineering and scientific applications. It provides a high-level programming language with hundreds of built-in functions for numerical computation. Additionally, it encompasses Xcos, which is a Causal Block Diagrams-based graphical editor for modeling and simulation of dynamical sy...

This two volume set LNCS 9827 and LNCS 9828 constitutes the refereed proceedings of the 27th International Conference on Database and Expert Systems Applications, DEXA 2016, held in Porto, Portugal, September 2016. The 39 revised full papers presented together with 29 short papers were carefully reviewed and selected from 137 submissions. The paper...