Kurt Rothermel

Universität Stuttgart · Institute of Parallel and Distributed Systems

Many applications of cyber-physical systems require real-time communication: manufacturing, automotive, etc. Recent Ethernet standards for Time Sensitive Networking (TSN) offer time-triggered scheduling in order to guarantee low latency and jitter bounds. This requires precise frame transmission planning, which becomes especially hard when dealing...

Due to the growing complexity of modern data centers, failures are not uncommon any more. Therefore, fault tolerance mechanisms play a vital role in fulfilling the availability requirements. Multiple availability models have been proposed to assess compute systems, among which Bayesian network models have gained popularity in industry and research...

Real-time video analytics typically require video frames to be processed by a query to identify objects or activities of interest while adhering to an end-to-end frame processing latency constraint. Such applications impose a continuous and heavy load on backend compute and network infrastructure because of the need to stream and process all video...

Due to the growing complexity of modern data centers, failures are not uncommon any more. Therefore, fault tolerance mechanisms play a vital role in fulfilling the availability requirements. Multiple availability models have been proposed to assess compute systems, among which Bayesian network models have gained popularity in industry and research...

Deterministic real-time communication with bounded delay is an essential requirement for many safety-critical cyber-physical systems, and has received much attention from major standardization bodies such as IEEE and IETF. In particular, Ethernet technology has been extended by time-triggered scheduling mechanisms in standards like TTEthernet and T...

Many networked applications, e.g., in the domain of cyber-physical systems, require strict service guarantees for time-triggered traffic flows, usually in the form of jitter and latency bounds. It is a notoriously hard problem to compute a network-wide traffic plan, i.e., a set of routes and transmission schedules, that satisfies these requirements...

Many networked applications, e.g., in the domain of cyber-physical systems, require strict service guarantees for time-triggered traffic flows, usually in the form of jitter and latency bounds. It is a notoriously hard problem to compute a network-wide traffic plan, i.e., a set of routes and transmission schedules, that satisfies these requirements...

Numerical simulations on mobile devices are an important tool for engineers and decision makers in the field. However, providing simulation results on mobile devices is challenging due to the complexity of the simulation, requiring remote server resources and distributed mobile computation. The additional large size of multi-dimensional simulation...

Many networked applications, e.g., in the domain of cyber-physical systems, require strict service guarantees, usually in the form of jitter and latency bounds, for time-triggered traffic flows. It is a notoriously hard problem to compute a network-wide traffic plan that satisfies these requirements, and dynamic changes in the flow set add even mor...

Many networked applications, e.g., in the domain of cyber-physical systems, require strict service guarantees, usually in the form of jitter and latency bounds, for time-triggered traffic flows. It is a notoriously hard problem to compute a network-wide traffic plan that satisfies these requirements, and dynamic changes in the flow set add even mor...

Availability analysis is indispensable in evaluating the dependability of safety and business-critical systems, for which fault tree analysis (FTA) has proven very useful throughout research and industry. Fault trees (FT) can be analyzed by means of a rich set of mathematical models. One particular model are Bayesian networks (BNs) which have gaine...

Availability analysis is indispensable in evaluating the dependability of safety and business-critical systems, for which fault tree analysis (FTA) has proven very useful throughout research and industry. Fault trees (FT) can be analyzed by means of a rich set of mathematical models. One particular model are Bayesian networks (BNs) which have gaine...

In complex event processing (CEP), load shedding is performed to maintain a given latency bound during overload situations when resources are limited. However, shedding load implies degradation in the quality of results (QoR). Therefore, it is crucial to shed load in a way that has the lowest impact on QoR. Researchers, in the CEP domain, propose t...

This article considers the control of linear time-invariant systems over a time-slotted communication network, which supports infrequent deterministic transmission slots and additional opportunistic transmission slots that can only be used if the network traffic satisfies a desired traffic specification. For two scenarios, controllers as well as co...

In complex event processing (CEP), load shedding is performed to maintain a given latency bound during overload situations when there is a limitation on resources. However, shedding load implies degradation in the quality of results (QoR). Therefore, it is crucial to perform load shedding in a way that has the lowest impact on QoR. Researchers, in...

In complex event processing (CEP), load shedding is performed to maintain a given latency bound during overload situations when there is a limitation on resources. However, shedding load implies degradation in the quality of results (QoR). Therefore, it is crucial to perform load shedding in a way that has the lowest impact on QoR. Researchers, in...

Recently, indoor modeling has gained increased attention, thanks to the immense need for realizing efficient indoor location-based services. Indoor environments differ from outdoor spaces in two aspects: spaces are smaller and there are many structural objects such as walls, doors, and furniture. To model the indoor environments in a proper manner,...

Networked control systems (NCS) consist of sensors and actuators that are connected to a controller through a packet-switched network in a feedback loop to control physical systems in diverse application areas such as industry, automotive, or power infrastructure. The control of critical real-time systems places strong requirements on the latency a...

Traffic planning is the key enabler of time-triggered real-time communication in distributed systems, and it is known to be notoriously hard. Current approaches predominantly tackle the problem in the domain of the traffic planning problem, e.g., by formulating constraints on the transmission schedules for individual data streams, or the links used...

Complex event processing systems process the input event streams on-the-fly. Since input event rate could overshoot the system's capabilities and results in violating a defined latency bound, load shedding is used to drop a portion of the input event streams. The crucial question here is how many and which events to drop so the defined latency boun...

Today most applications continuously produce information under the form of streams, due to the advent of the means of collecting data. Sensors and social networks collect an immense variety and volume of data, from different real-life situations and at a considerable velocity. Increasingly, applications require processing of heterogeneous data stre...

Complex event processing (CEP) systems continuously process input event streams to detect patterns. Over time, the input event rate might fluctuate and overshoot the system's capabilities. One way to reduce the overload on the system is to use load shedding. In this paper, we propose a load shedding strategy for CEP systems which drops a portion of...

Recently, indoor modeling has gained increased attention thanks to the immense need for realizing efficient indoor location-based services. Indoor environments de facto differ from outdoor spaces in two aspects: spaces are smaller and there are many structural objects such as walls, doors, and furniture. To model the indoor environments in a proper...

Recently, named data networking (NDN) has been introduced to connect the world of computing devices via naming data instead of their containers. Through this strategic change, NDN brings several new features to network communication, including in-network caching, multipath forwarding, built-in multicast, and data security. Despite these unique feat...

In complex event processing (CEP), load shedding is performed to maintain a given latency bound during overload situations when there is a limitation on resources. However, shedding load implies degradation in the quality of results (QoR). Therefore, it is crucial to perform load shedding in a way that has the lowest impact on QoR. Researchers, in...

Control mechanisms of stream processing applications (SPAs) that ensure latency bounds at minimal runtime cost mostly target a specific infrastructure, e.g., homogeneous nodes. With the growing popularity of the Internet of Things, fog, and edge computing, SPAs are more often distributed on heterogeneous infrastructures, triggering the need for a h...

Complex event processing systems process the input event streams on-the-fly. Since input event rate could overshoot the system's capabilities and results in violating a defined latency bound, load shedding is used to drop a portion of the input event streams. The crucial question here is how many and which events to drop so the defined latency boun...

Numerical simulations on mobile devices are an important tool for engineers and decision makers in the field. However, providing simulation results on mobile devices is challenging due to the complexity of the simulation, requiring remote server resources and distributed mobile computation. The additional large size of multi-dimensional simulation...

Internet of Things (IoT) is expanding at a rapid rate where it allows for virtually endless opportunities and connections to take place. In general, IoT opens the door to a myriad of applications but also to many challenges. One of the major challenges is how to efficiently retrieve the sensory data from âresources-limitedâ IoT devices. Such device...

Converged networks support applications with completely different (real-time) requirements. The communication paradigms offered in converged networks are predominantly treated as separate entities from the perspective of traffic engineering, e.g., time-triggered traffic for closed-loop control systems, shaped traffic for multimedia-streaming applic...

Network elements (e.g., switches), which intermit service, i.e., stop forwarding and transmission of data according to a repeating schedule, can be found in many real-time capable communication networks, e.g., communication networks with TDMA, Ethernet with Time-aware Shapers or low-power wireless networks. The behavior of those network elements de...

Network elements (e.g., switches), which intermit service, i.e., stop forwarding and transmission of data according to a repeating schedule, can be found in many real-time capable communication networks, e.g., communication networks with TDMA, Ethernet with Time-aware Shapers or low-power wireless networks. The behavior of those network elements de...

Typically, Function-as-a-Service (FaaS) involves state-less replication with very large numbers of instances. The reliability of such services can be evaluated using Bayesian Networks and k-out-of-n models. However, existing k-out-of-n models do not scale to the larger number of hosts of FaaS services. Therefore, we propose a scalable k-out-of-n mo...

IEEE 802.1 Time-sensitive Networking (TSN) enables real-time communication with deterministically bounded network delay and jitter over standard IEEE 802.3 networks ("Ethernet"). In particular, TSN specifies a time-triggered scheduling mechanism in IEEE Std 802.1Qbv implemented by switches to control when outgoing queues get access to switch ports....

In this paper, we present a communication abstraction for Networked Control Systems that is characterized by a slotted transmission classification model. We discuss, how such a model can be implemented over local area networks by using IEEE Time Sensitive Networking methods. Furthermore, it is shown how asymptotic stability can be analyzed for line...

Control mechanisms of stream processing applications (SPAs) that ensure latency bounds at minimal runtime cost mostly target a specific infrastructure, e.g., homogeneous nodes. With the growing popularity of the Internet of Things, fog, and edge computing, SPAs are more often distributed on het- erogeneous infrastructures, triggering the need for a...

Complex event processing systems process the input event streams on-the-fly. Since input event rate could overshoot the systemâs capabilities and results in violating a defined latency bound, load shedding is used to drop a portion of the input event streams. The crucial question here is how many and which events to drop so the defined latency boun...

Complex event processing (CEP) systems continuously process input event streams to detect patterns. Over time, the input event rate might fluctuate and overshoot the systemâs capabilities. One way to reduce the overload on the system is to use load shedding. In this paper, we propose a load shedding strategy for CEP systems which drops a portion of...

To secure location privacy of social networks users in a manageable way, a large body of existing works focuses on automating the location-sharing decisions with online social contacts by defining machine-learning based location sharing policies. These policies are learned over actual user-responses to information sharing requests from their social...

To secure location privacy of social networks users in a manageable way, a large body of existing works focuses on automating the location-sharing decisions with online social contacts by defining machine-learning based location sharing policies. These policies are learned over actual user-responses to information sharing requests from their social...

Many important real-world applications-such as social networks or distributed data bases-can be modeled as hypergraphs. In such a model, vertices represent entities-such as users or data records-whereas hyperedges model a group membership of the vertices-such as the authorship in a specific topic or the membership of a data record in a specific rep...

test Recently, mobile crowdsensing has become an appealing paradigm thanks to the ubiquitous presence of powerful mobile devices. Indoor mapping, as an example of crowdsensingdriven applications, is essential to provide many indoor locationbased services, such as emergency response, security, and tracking/navigation in large buildings. In this real...

Code offloading strives for increasing the energy efficiency and execution speed of mobile applications on resource-constrained mobile devices. First approaches only considered a code offloading between two (or three) tiers, executing code either locally on a mobile device or remotely on a powerful server. However, new execution environments compri...

Recently, mobile crowdsensing has become an appealing paradigm thanks to the ubiquitous presence of powerful mobile devices. Indoor mapping, as an example of crowdsensing driven^applications, is essential to provide many indoor locationbased services, such as emergency response, security, and tracking/ navigation in large buildings. In this realm,...

Location information sharing on popular online social networking platforms like Facebook and Foursquare brings mutual benefits for the users of these platforms (e.g., free location-based services) as well as the platform providers (e.g., location-based businesses). An obvious problem however that impedes these mutual benefits are privacy concerns r...

IEEE 802.1Q networks with extensions for time-sensitive networking aim to enable converged networks. Converged networks support hard-real time communication services in addition to the currently supported services classes. Real-time communication in these networks requires routes and schedules for the real-time transmissions. We present a formulati...

The Internet of Things (IoT) envisions a huge number of networked sensors connected to the internet. These sensors collect large streams of data which serve as input to wide range of IoT applications and services such as e-health, e-commerce, and automotive services. Complex Event Processing (CEP) is a powerful tool that transforms streams of raw s...

In-network computing using programmable networking hardware is a strong trend in networking that promises to reduce latency and consumption of server resources through offloading to network elements (programmable switches and smart NICs). In particular, the data plane programming language P4 together with powerful P4 networking hardware has spawned...

Arising user-centric graph applications such as route planning and personalized social network analysis have initiated a shift of paradigms in modern graph processing systems towards multi-query analysis, i.e., processing multiple graph queries in parallel on a shared graph. These applications generate a dynamic number of localized queries around q...

Arising user-centric graph applications such as route planning and personalized social network analysis have initiated a shift of paradigms in modern graph processing systems towards multi-query analysis, i.e., processing multiple graph queries in parallel on a shared graph. These applications generate a dynamic number of localized queries around q...

With the vision of Internet of Things gaining popularity at a global level, efficient publish/subscribe middleware for communication within and across data centers is extremely desirable. In this respect, the very popular Software-Defined Networking, which enables publish/subscribe middleware to perform line-rate filtering of events directly on har...

Recently, point clouds have been efficiently utilized for medical imaging, modeling urban environments, and indoor modeling. In this realm, several mobile platforms, such as Google Tango and Apple ARKit, have been released leveraging 3D mapping, augmented reality, etc. In modeling applications, these modern mobile devices opened the door for crowd-...

Workflows are the de facto standard for managing business processes and allow businesses to automate interactions between business locations and partners residing anywhere on the planet. This, however, requires the workflows to be executed in a dynamic environment, where device and communication failures occur frequently, making availability a key...

Currently, various hardware and software companies are developing augmented reality devices, most prominently Microsoft with its Hololens. Besides gaming, such devices can be used for serious pervasive applications, like interactive mobile simulations to support engineers in the field. Interactive simulations have high demands on resources, which t...

Recently, graph processing systems such as Pregel, PowerGraph, or GraphX gained popularity due to their superior performance of data analytics on graph-structured data. These systems employ partitioning algorithms to parallelize graph execution while minimizing inter-partition communication. Recent partitioning algorithms, however, unrealistically...

Many important real-world applications---such as social networks or distributed data bases---can be modeled as hypergraphs. In such a model, vertices represent entities---such as users or data records---whereas hyperedges model a group membership of the vertices---such as the authorship in a specific topic or the membership of a data record in a sp...

We propose two extensions for a state-of-the-art method of rollback-recovery in distributed CEP (complex event processing). In CEP, an operator network is used to search for patterns in events streams. Sometimes these operators fail and lose their state. Rollback-recovery is a method for dealing with such state losses. The type of rollback-recovery...

In recent years, the graph partitioning problem gained importance as a mandatory preprocessing step for distributed graph processing on very large graphs. Existing graph partitioning algorithms minimize partitioning latency by assigning individual graph edges to partitions in a streaming manner --- at the cost of reduced partitioning quality. Howev...

Distributed Complex Event Processing (DCEP) is a paradigm to infer the occurrence of complex situations in the surrounding world from basic events like sensor readings. In doing so, DCEP operators detect event patterns on their incoming event streams. To yield high operator throughput, data parallelization frameworks divide the incoming event strea...

Several networking architectures have been developed atop IEEE 802.3 networks to provide real-time communication guarantees for time-sensitive applications in industrial automation systems. The basic principle underlying these technologies is the precise transmission scheduling of time-triggered traffic through the network for providing determinist...