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In this paper we present some experiments on the MySQL database server. The objective of the experiments was to investigate the high load dynamics for varying relation sizes and requests. We show that the dynamics for SELECT (read) requests can be modeled as a modified M/M/1 system, whereas, the dynamics for UPDATE (write) are completely different. Our results can be used for designing control and
Definition and reuse of robot instructions is still an art that requires extensive engineering, not only of the infrastructure but also of the adaptation of robot capabilities to the context and domain at hand. Technical approaches are numerous, but the lack of practical success is an indication of hidden difficulties, which we have experienced as complications over the last two decades. Based on
The performance of wireless communications at sea are often limited by fading caused by reflections at the sea surface. The reliability could potentially be improved by employing multiple antennas. We have conducted massive multiple-input multiple-output (MIMO) measurements at sea in order to evaluate the performance. The measurements were conducted at 5.6 GHz with 64 dual-polarized antennas, whic
Bayesian optimization is a widely used method for optimizing expensive black-box functions, with Expected Improvement being one of the most commonly used acquisition functions. In contrast, information-theoretic acquisition functions aim to reduce uncertainty about the function’s optimum and are often considered fundamentally distinct from EI. In this work, we challenge this prevailing perspective
A broadband high gain metasurface-based Fabry–Perot resonant cavity antenna (FPRCA) for polarization reconfigurable is proposed in this article. The antenna features a microstrip source antenna with a single-layer 2 × 2 circular patch metasurface, a ground plane, and a double-layer partially reflective surface (PRS), along with four resistors and two diodes. Characteristic mode analysis (CMA) is p
OBJECTIVE: To investigate a recently developed MRI technique for mapping the Mean Diffusivity of Tissue (MDT), which improves diffusion MRI imaging of the cerebral cortex by reducing partial volume effects from cerebrospinal fluid (CSF). As cortical lesions are common in patients with focal epilepsy, we explored the clinical value of MDT imaging in patients with drug resistant epilepsy and low-gra
The reassignment technique is used to increase localization for signal components in the time-frequency representation. The technique gives perfect localization for linear chirp signals and constant frequency signals. Despite the recent interest in using the reassignment technique to determine phase-shifts, no general expression of cross-spectrogram reassignment vectors exists. This submission aim
Source code analysis is ubiquitous in the development of software tools, for example in compilers to detect compile-time errors and possible optimizations, inIDEs to provide interactive coding assistance, and in stand-alone analysis tools todetect bugs. There are several techniques that have been developed to help theanalysis developer, including one called Reference Attribute Grammars (RAGs).With
Iterative algorithms are becoming more common in modern systems. This ranges from algorithms for communicationsystems receivers, machine learning, group testing, and various computation problems. The success of thesealgorithms lies in the ability to simplify computation by breaking down the system into components and exchangingmessages on graphs. The graph has the components as nodes and connectio
Cellular-based localization and sensing pave the way for a variety ofapplications across various domains, ranging from autonomous driv-ing to emergency care and intelligent traffic management. Althoughtraditional methods have been effective, they still face challenges such as therequirement for highly accurate models and the inherent complexity of thealgorithms. This thesis explores the potential
Formal models for the safety validation of autonomous vehicles have become increasingly important. To this end, we present a safety framework for longitudinal automated driving. This framework enables the calculation of minimum safe inter-vehicular distances for arbitrary ego vehicle control policies in a computationally efficient manner. We use this framework to enhance and generalize the Respons
We recently proposed a quantitative group testing (GT) scheme with low-complexity peeling decoding based on low-density parity-check (LDPC) codes. Based on finite length simulations and a density evolution analysis we were able to demonstrate that simple (dv,dc)-regular LDPC codes can be more efficient for GT than existing generalized LDPC (GLDPC) code constructions based on BCH component codes. E
Future wireless systems are envisioned to be able to deliver ultra-reliable and low-latency communication.The third generation partner project (3GPP) has identified three different usage scenarios such as enhanced mobile broadband, massive machine-type communication, and ultra-reliable low latency communication.In each of those scenarios, several services and applications can be implemented, e.g.
In this work, we present a method for acquiring, storing, and using scene data to enable realistic shading of virtual objects in an augmented reality application. Our method allows for sparse sampling of the environment’s lighting condition while still delivering a convincing shading to the rendered objects. We use common camera parameters, provided by a head-mounted camera, to get lighting inform
In this paper we present the concept for a teleoperation system for semi-autonomous robotic boats using virtual reality. This system can be used for monitoring autonomous driving as well as for direct manual control. The integration of live sensor data is possible as well as the integration of past measurement results and their correct registration within the virtual representation. Initial field
Modern subgraph-finding algorithm implementations consist of thousands of lines of highly optimized code, and this complexity raises questions about their trustworthiness. Recently, some state-of-the-art subgraph solvers have been enhanced to output machine-verifiable proofs that their results are correct. While this significantly improves reliability, it is not a fully satisfactory solution, sinc
During recent years, research on authenticated encryption has been thriving through two highly active and practice-motivated research directions: provably secure leakage-resilience schemes and key- or context-commitment security. However, the intersection of both fields had been overlooked until very recently. In ToSC 1/2024, Struck and Weish\"aupl studied generic compositions of Encryption scheme
Streaming applications, such as MPEG video encoders or sensor processing pipelines, are increasing in complexity as well as the diversity of platforms that they run on. The toolchains handling these applications must keep up with this increase at all levels of abstraction. The Actor Machine (AM) is an intermediate representation in the toolchain that we make use of. Large AMs are difficult to work
Wireless charging of smartphones using inductive wireless power transfer (IWPT) has become very popular. However, the efficiency of IWPT systems can decrease substantially when the transmitting and receiving coils are not closely coupled. One popular approach to mitigate the efficiency degradation is to utilize higher frequency. However, the higher efficiency is only achieved at a specific range o
