arXiv subjects

Tobias Brandt

Publications and source records attributed to Tobias Brandt.

5 recordsLinked to original sources

arXiv2025

Accurate and Extensible Symbolic Execution of Binary Code based on Formal ISA Semantics

Symbolic execution is an SMT-based software verification and testing technique. Symbolic execution requires tracking performed computations during software simulation to reason about branches in the software under test. The prevailing approach on symbolic execution of binary code tracks computations by transforming the code to be tested to an architecture-independent IR and then symbolically executes this IR. However, the resulting IR must be semantically equivalent to the binary code, making this process complex and error-prone. The semantics of the binary code are specified by the targeted ISA, commonly given in natural language and requiring a manual implementation of the transformation to an IR. In recent years, the use of formal languages to describe ISA semantics in a machine-readable way has gained increased popularity. We investigate the utilization of such formal semantics for symbolic execution of binary code, achieving an accurate representation of instruction semantics. We present a prototype for the RISC-V ISA and conduct a case study to demonstrate that it can be easily extended to additional instructions. Furthermore, we perform an experimental comparison with prior work which resulted in the discovery of five previously unknown bugs in the ISA implementation of the popular IR-based symbolic executor angr.

cs.SE↗

arXiv2024

MOSAIK 3.0: Combining Time-Stepped and Discrete Event Simulation

Co-simulation is commonly used for the analysis of complex cyber-physical energy systems (CPES). Different domain-specific simulation tools and modeling approaches are used to simulate all or parts of the system. The co-simulation framework mosaik is a powerful tool to couple these simulation tools and models. This paper identifies the limitations of mosaik 2 for simulating systems that combine continuous and discrete behavior, and introduces the new version mosaik 3.0 with improved event capabilities to efficiently combine time-stepped and discrete event simulation. Here it is explained how these extensions and new features of mosaik can be applied and implemented for extended co-simulation scenarios.

cs.CE↗

arXiv2023

3D Analytics: Opportunities and Guidelines for Information Systems Research

Progress in sensor technologies has made three-dimensional (3D) representations of the physical world available at a large scale. Leveraging such 3D representations with analytics has the potential to advance Information Systems (IS) research in several areas. However, this novel data type has rarely been incorporated. To address this shortcoming, this article first presents two showcases of 3D analytics applications together with general modeling guidelines for 3D analytics, in order to support IS researchers in implementing research designs with 3D components. Second, the article presents several promising opportunities for 3D analytics to advance behavioral and design-oriented IS research in several contextual areas, such as healthcare IS, human-computer interaction, mobile commerce, energy informatics and others. Third, we investigate the nature of the benefits resulting from the application of 3D analytics, resulting in a list of common tasks of research projects that 3D analytics can support, regardless of the contextual application area. Based on the given showcases, modeling guidelines, research opportunities and task-related benefits, we encourage IS researchers to start their journey into this largely unexplored third spatial dimension.

cs.HC↗

arXiv2021

Towards a Secure and Reliable IT-Ecosystem in Seaports

Digitalization in seaports dovetails the IT infrastructure of various actors (e.g., shipping companies, terminals, customs, port authorities) to process complex workflows for shipping containers. The security of these workflows relies not only on the security of each individual actor but actors must also provide additional guarantees to other actors like, for instance, respecting obligations related to received data or checking the integrity of workflows observed so far. This paper analyses global security requirements (e.g., accountability, confidentiality) of the workflows and decomposes them - according to the way workflow data is stored and distributed - into requirements and obligations for the individual actors. Security mechanisms are presented to satisfy the resulting requirements, which together with the guarantees of all individual actors will guarantee the security of the overall workflow.

cs.CR↗

arXiv2012

Simulating Sinking Satellites with SUPERBOX-10

SUPERBOX-10 is the successor of SUPERBOX, a particle-mesh code where additional grids and sub-grids are applied to regions of high particle density. Previous limitations have been solved. For instance, the vertical resolution is improved considerably when flattened grids are used. Since the computationally most intensive part is the Fast Fourier Transform, we introduce a parallelised version using the library FFTW, resulting in a speed-up of a few. The new features are tested using a galaxy model consisting of an exponential disc, a bulge and a dark matter halo. We demonstrate that the use of flattened grids efficiently reduces numerical heating. We simulate the merging of disc-bulge-halo galaxies with small spherical satellites. As a result, satellites on orbits with both low eccentricity and inclination heat the disc most efficiently. Moreover, we find that most of the satellite's energy and angular momentum is transfered to the halo.

astro-ph.GA↗