Pseudo-Boolean Constraint Encodings for Conjunctive Normal Form and their Applications

In contrast to a single clause a pseudo-Boolean (PB) constraint is much more expressive and hence it is easier to define problems with the help of PB constraints. But while PB constraints provide us with a high-level problem description, it has been shown that solving PB constraints can be done faster with the help of a SAT solver. To apply such a solver to a PB constraint we have to encode it with clauses into conjunctive normal form (CNF). While we can find a basic encoding into CNF which is equivalent to a given PB constraint, the solving time of a SAT solver significantly depends on different properties of an encoding, e.g. the number of clauses or if generalized arc consistency (GAC) is maintained during the search for a solution. There are various PB encodings that try to optimize or balance these properties. This thesis is about such encodings. For a better understanding of the research field an overview about the state-of-the art encodings is given. The focus of the overview is a simple but complete description of each encoding, such that any reader could use, implement and extent them in his own work. In addition two novel encodings are presented: The Sequential Weight Counter (SWC) encoding and the Binary Merger Encoding. While the SWC encoding provides a very simple structure – it is listed in four lines – empirical evaluation showed its practical usefulness in various applications. The Binary Merger encoding reduces the number of clauses a PB encoding needs while having the important GAC property. To the best of our knowledge currently no other encoding has a lower upper bound for the number of clauses produced by a PB encoding with this property. This is an important improvement of the state-of-the art, since both GAC and a low number of clauses are vital for an improved solving time of the SAT solver. The thesis also contributes to the development of new applications for PB constraint encodings. The programming library PBLib provides researchers with an open source implementation of almost all PB encodings – including the encodings for the special cases at-most-one and cardinality constraints. The PBLib is also the foundation of the presented weighted MaxSAT solver optimax, the PBO solver pbsolver and the WBO, PBO and weighted MaxSAT solver npSolver

The Distributed Discrete Gaussian Mechanism for Federated Learning with Secure Aggregation

We consider training models on private data that is distributed across user devices. To ensure privacy, we add on-device noise and use secure aggregation so that only the noisy sum is revealed to the server. We present a comprehensive end-to-end system, which appropriately discretizes the data and adds discrete Gaussian noise before performing secure aggregation. We provide a novel privacy analysis for sums of discrete Gaussians. We also analyze the effect of rounding the input data and the modular summation arithmetic. Our theoretical guarantees highlight the complex tension between communication, privacy, and accuracy. Our extensive experimental results demonstrate that our solution is essentially able to achieve a comparable accuracy to central differential privacy with 16 bits of precision per value

Machbarkeitsstudie Schultypisierung : Kooperationsprojekt IAB / BA-Zentrale (SP III 22) (Feasiblity study in classifying schools : Cooperation project IAB/BA Central Office (SP III 22))

"The project has assessed whether a classification of secondary schools with regard to their success in leading school-leavers to an apprentice training or a comparable training scheme is possible. The approach intended to use the same methods as were used in the classification of regional labour markets. For this feasibility study, process data from the Federal Employment Agency (BA) were used as well as school statistics from the Federal Laender which were involved. For a large number of young people who were found in the BA systems VerBIS and COMPAS.NT we succeeded in identifying their former schools. Comparing this information with school leaver statistics showed that the data could have been used for our purposes. In the end, however, we came to the conclusion that it was not possible to link these data to a target indicator. Despite good results in creating a data set with school related data, we thus found that it was not possible to classify schools according to the classification of regional labour markets." (Authors' abstract, IAB-Doku) ((en))Hauptschulabschluss, Realschulabschluss, Gesamtschule, Datengewinnung, Bildungsstatistik, Ausbildung, benachteiligte Jugendliche, Regressionsanalyse, Clusteranalyse, Bundesländer, Bundesagentur für Arbeit, Statistisches Bundesamt, Schulabgänger, Berufsberatung

First Molecular Evidence for Underestimated Biodiversity of Rhachotropis (Crustacea, Amphipoda), with Description of a New Species

The crustacean genus Rhachotropis has a worldwide distribution and amongst the largest bathymetric range known from any amphipod genus. DNA barcoding of new material from around New Zealand and the Ross Sea indicated depth-related biogeographic patterns. New Zealand Rhachotropis do not form a monophyletic clade. Species from bathyal depths on the Chatham Rise, east of New Zealand, show lower sequence divergence to bathyal species from California and the Arctic than to abyssal New Zealand species. Species sampled in the Kermadec Trench, north of New Zealand below 5000 m, seem to be more closely related to Ross Sea abyssal species than to the New Zealand shelf species. The worldwide geographic and bathymetric distribution for all Rhachotropis species is presented here. Depth may have a greater influence on phylogeny than geographic distance. Molecular and morphological investigations of Rhachotropis specimens from the Chatham Rise, New Zealand revealed a species new to science which is described in detail, including scanning electron microscopy. This increases the number of described species of Rhachotropis to 60 worldwide

Fast, predictable and low energy memory references through architecture-aware compilation

The design of future high-performance embedded systems is hampered by two problems: First, the required hardware needs more energy than is available from batteries. Second, current cache-based approaches for bridging the increasing speed gap between processors and memories cannot guarantee predictable real-time behavior. A contribution to solving both problems is made in this paper which describes a comprehensive set of algorithms that can be applied at design time in order to maximally exploit scratch pad memories (SPMs). We show that both the energy consumption as well as the computed worst case execution time (WCET) can be reduced by up to to 80% and 48%, respectively, by establishing a strong link between the memory architecture and the compiler

The role of hyperfine coupling in magnetic and quadrupolar ordering of Pr3Pd20Si6

We study the ternary clathrate Pr3Pd20Si6 in specific heat and AC-susceptibility measurements on a high-quality single crystal, distinguishing antiferromagnetic (AFM) and antiferroquadrupolar (AFQ) ordering on two sublattices of inequivalent Pr sites. The specific heat shows the direct involvement of nuclear spin degrees of freedom in the AFM ordering, which is well supported by our calculation of the hyperfine level scheme without adjustable parameters. Pr3Pd20Si6 is therefore one of the rare materials where the nuclear moments are involved in the formation of the magnetic ground state.Comment: 5 pages, 5 figure

The history of the development of the regular straight stem in hip arthroplasty.

Since the middle of the 20th century, total hip arthroplasty has become a very successful treatment for all end-stage diseases of the hip joint. Charnley solved with his low frictional torque arthroplasty the problem of wear and friction with the introduction of a new bearing couple and the reduction of the head size, which set the prerequisite for the further development of stem design. This narrative review presents the major developments of regular straight stems in hip arthroplasty. It does not only provide an overview of the history but also assembles the generally scarce documentation available regarding the rationale of developments and illustrates often-unsuspected links. Charnley's success is based on successfully solving the issue of fixation of the prosthetic components to the bone, using bone cement made of polymethyl-methacrylate. In the field of cemented anchorage of the stem, two principles showing good long-term revision rates emerged over the years: the force-closed and the shape-closed principles. The non-cemented anchorage bases on prosthesis models ensure enough primary stability for osteointegration of the implant to occur. For bone to grow onto the surface, not only sufficient primary stability is required but also a suitable surface structure together with a biocompatible prosthetic material is also necessary

Aktivierung, Erwerbstätigkeit und Teilhabe: vier Jahre Grundsicherung für Arbeitsuchende

Mit der Einführung des SGB II im Jahr 2005 wurden Arbeitslosen- und Sozialhilfe zur Grundsicherung für erwerbsfähige Hilfsbedürftige zusammengelegt. Ziel der Arbeitsmarktreformen war es auch, Leistungsempfänger zu aktivieren und möglichst schnell zu integrieren. Damit hat sich die Arbeitsmarktpolitik von einem bloßen Versorgungssystem entfernt und die Betreuung einerseits sowie die Zumutungen andererseits verstärkt. Die Diskussion über die Folgen dieser Reformen beherrscht weiterhin die öffentliche Diskussion in Deutschland. Vier Jahre nach der Einführung ist es Zeit für eine erste Zwischenbilanz. Der hier vorgelegte Bericht fasst die Forschungsergebnisse zum SGB II zusammen, die das IAB erarbeitet hat und stellt die Befunde in einen größeren Zusammenhang. So wird der Stand des Wissens zum Übergang vom alten in das neue System, zum Prozess und zur Wahrnehmung von Aktivierung und Betreuung, zu den Instrumenten und deren Wirkung sowie zur Bedeutung der Reform für den Arbeitsmarkt beschrieben. Damit zeigt der Band auch auf, wo die Forschung zur Grundsicherung heute steht und welche Fragen künftig zu beantworten sind. Die Wirkung des Gesetzes auf verschiedene Dimensionen gesellschaftlicher Teilhabe bildet den roten Faden der Darstellung