Tobias Philipp

secunet Security Networks AG · SINA Development and Verification Team

In a co-design environment changes need to be integrated quickly and in an automated manner. This paper considers the challenge of creating and optimizing a global logistics system for the construction of a passenger aircraft within a co-design approach with respect to key performance indicators (like cost, time or resilience). The product in quest...

In a co-design environment changes need to be integrated quickly and in an automated manner. This paper considers the challenge of creating and optimizing a global logistics system for the construction of a passenger aircraft within a co-design approach with respect to key performance indicators (like cost, time or resilience). The product in quest...

Zusammenfassung Efficient and verifiable SAT proof checking is an important topic in logic-based AI as well as for trusted explanations from machine learning models. However, the development of efficient and verifiable methods often leads to advanced methods in interactive theorem provers or workarounds, such as untrusted proof-annotation phases, d...

Smoke testing is an important method to increase stability and reliability of hardware- gramming, Testing depending systems. Due to concurrent access to the same physical resource and the impracticality of the use of virtualization, smoke testing requires some form of planning. In this paper, we propose to decompose test cases in terms of atomic ac...

Answer Set Programming (ASP) solvers are highly-tuned and complex procedures that implicitly solve the consistency problem, i.e., deciding whether a logic program admits an answer set. Verifying whether a claimed answer set is formally a correct answer set of the program can be decided in polynomial time for (normal) programs. However, it is far fr...

Answer Set Programming (ASP) solvers are highly-tuned and complex procedures that implicitly solve the consistency problem, i.e., deciding whether a logic program admits an answer set. Verifying whether a claimed answer set is formally a correct answer set of the program can be decided in polynomial time for (normal) programs. However, it is far fr...

In everyday life, it seems that we prefer some explanations for an observation over others because of our contextual background knowledge. Reiter already tried to specify a mechanism within logic that allows us to avoid explicitly considering all exceptions in order to derive a conclusion w.r.t. the usual case. In a recent paper, a contextual reaso...

In everyday life, it seems that when we observe something, then, while searching for explanations, we assume some explanation more plausible to others, simply because of our contextual background. Recently, a contextual reasoning approach has been presented, which takes into account this contex-tual background and allows us to specify context withi...

Unsatisfiability proofs in the DRAT format became the de facto standard to increase the reliability of contemporary SAT solvers. We consider the problem of generating proofs for the XOR reasoning component in SAT solvers and propose two methods: direct translation transforms every XOR constraint addition inference into a DRAT proof, whereas T-trans...

PBLib is an easy-to-use and efficient library, written in C++, for translating pseudo-Boolean (PB) constraints into CNF. We have implemented fifteen different encodings of PB constraints. Our aim is to use efficient encodings, in terms of formula size and whether unit propagation maintains generalized arc consistency. Moreover, PBLib normalizes PB...

SAT solvers are highly efficient programs that decide the satisfiability problem for propositional formulas in conjunctive normal form. Contemporary SAT solvers combine many advanced techniques such as clause sharing and inprocessing. Clause sharing is a form of cooperation in parallel SAT solvers based on clause learning, whereas inprocessing simp...

In this paper we answer the open question for the existence of a more compact encoding from Pseudo-Boolean constraints into CNF that maintains generalized arc consistency by unit propagation, formalized by Bailleux et al. in [21]. In contrast to other encodings our approach is defined in an abstract way and we present a concrete instantiation, resu...

Many real world problems are solved with satisfiability testing (SAT). However, SAT solvers have documented bugs and therefore the answer that a formula is unsatisfiable can be incorrect. Certifying algorithms are an attractive approach to increase the reliability of SAT solvers. For unsatisfiable formulas an unsatisfiability proof has to be create...

Inprocessing is to apply clause simplification techniques during search and is a very attractive idea since it allows to apply computationally expensive techniques. In this paper we present the search space decomposition formalism SSD that models parallel SAT solvers with clause sharing and inprocessing. The main result of this paper is that the sh...

As satisfiability (SAT) solver performance has improved, so has their complexity, which make it more likely that SAT solvers contain bugs. One important source of increased complexity is clause sharing in parallel SAT solvers. SAT solvers can emit a proof of unsatisfiability to gain confidence that the their results are correct. Such proofs must co...

Modern propositional satisfiability (or SAT) solvers are very powerful due to recent developments on the underlying data structures, the used heuristics to guide the search, the deduction techniques to infer knowledge, and the formula simplification techniques that are used during pre- and inprocessing. However, when all these techniques are put to...

Modern propositional satisfiability (or SAT) solvers are very powerful due to recent developments on the underlying data structures, the used heuristics to guide the search, the deduction techniques to in- fer knowledge, and the formula simplification techniques that are used during pre- and inprocessing. However, when all these techniques are put...

We present a formalism that models the computation of clause sharing portfolio solvers with inprocessing. The soundness of these solvers is not a straightforward property since shared clauses can make a formula unsatisfiable. Therefore, we develop characterizations of simplification techniques and suggest various settings how clause sharing and inp...

In this paper we contribute to bridging the gap between human reasoning as studied in Cognitive Science and commonsense reasoning based on formal logics and formal theories. In particular, the suppression task studied in Cognitive Science provides an interesting challenge problem for human reasoning based on logic. The work presented in the paper i...