Hoare-style Specifications as Correctness Conditions for Non-linearizable Concurrent Objects

Designing scalable concurrent objects, which can be efficiently used on multicore processors, often requires one to abandon standard specification techniques, such as linearizability, in favor of more relaxed consistency requirements. However, the variety of alternative correctness conditions makes it difficult to choose which one to employ in a particular case, and to compose them when using objects whose behaviors are specified via different criteria. The lack of syntactic verification methods for most of these criteria poses challenges in their systematic adoption and application. In this paper, we argue for using Hoare-style program logics as an alternative and uniform approach for specification and compositional formal verification of safety properties for concurrent objects and their client programs. Through a series of case studies, we demonstrate how an existing program logic for concurrency can be employed off-the-shelf to capture important state and history invariants, allowing one to explicitly quantify over interference of environment threads and provide intuitive and expressive Hoare-style specifications for several non-linearizable concurrent objects that were previously specified only via dedicated correctness criteria. We illustrate the adequacy of our specifications by verifying a number of concurrent client scenarios, that make use of the previously specified concurrent objects, capturing the essence of such correctness conditions as concurrency-aware linearizability, quiescent, and quantitative quiescent consistency. All examples described in this paper are verified mechanically in Coq.Comment: 18 page

Energy Optimization of Ship’s Shaft Generator with Permanent Magnet Synchronous Generator

With the development of power electronic systems, the use of a shaft generator in ship power plant systems is becoming more widespread. The use of the Permanent Magnet Synchronous Generator (PMSG) in these systems instead of the commonly used Electrically Excited Synchronous Generator (EESG) results in increased propulsion efficiency and reliability of the ship’s power plant. The lack of a voltage regulator in PMSG requires the use of an electronic power converter to maintain constant voltage parameters in the ship’s network, consisting of an active rectifier (AR) and an active network inverter (AI). The article presents AR tests in the PMAG-AR system, whose task is to maintain a constant voltage of the DC circuit when the shaft speed and load changes, as a result of which the selection of AI remains a simple choice. Energy optimization of the shaft generator system was also carried out, which allows reducing losses in AR and PMSG by limiting reactive power in the PMSG-AR system, which is particularly important in high power plants

Additional records and new synonyms of Cicindelidae and Carabidae (Coleoptera) from the lsland of Sakhalin in the Russian Far East

Faunistic records of three cicindelid and 47 carabid beetle species are given for the Island of Sakhalin in the Russian Far East. Most records refer to a material collected in 1993 and 1994 in SW Sakhalin by the two junior authors. The following five carabid species are here reported from Sakhalin for the first time: Bembidion chloropus Bates, Pterostichus neglectus A. Morawitz, Agonum jankowskii Lafer, A. piceum (Linnaeus) and Microlestes minutulus (Goeze). The gross distributions of all mentioned species are given, with special emphasis on the Far East. The following syn. nov. are given: Pterostichus (Euryperis) eximius A. Morawitz, 1862 (= crassiceps A. Morawitz, 1862; = rudnicus Jedlicka, 1938; = obliquebasalis Jedlicka, 1962; = prochazkorum Jedlicka, 1967; = sakhalinensis Kirschenhofer, 1985)

Contact-less measurements of Shubnikov-de Haas oscillations in the magnetically ordered state of CeAgSb2_2 and SmAgSb2_2 single crystals

Shubnikov - de Haas oscillations were measured in single crystals of highly metallic antiferromagnetic SmAgSb$_{2}$ and ferromagnetic CeAgSb$_{2}$ using a tunnel diode resonator. Resistivity oscillations as a function of applied magnetic field were observed via measurements of skin depth variation. The effective resolution of $\Delta\rho\simeq20$ p$\Omega$ allows a detailed study of the SdH spectra as a function of temperature. The effects of the Sm long - range magnetic ordering as well as its electronic structure ($4f$-electrons) on the Fermi surface topology is discussed

Physical properties of SrSn4 single crystals

We present detailed thermodynamic and transport measurements on single crystals of the recently discovered binary intermetallic superconductor, SrSn4. We find this material to be a slightly anisotropic three-dimensional, strongly-coupled, possibly multi-band, superconductor. Hydrostatic pressure causes a decrease in the superconducting transition temperature at the rate of -0.068 K/kbar. Band structure calculations are consistent with experimental data on Sommerfeld coefficient and upper superconducting critical field anisotropy and suggest complex, multi-sheet Fermi surface formed by four bands.Comment: Figure 11 correcte

Artificial Text Boundary Detection with Topological Data Analysis and Sliding Window Techniques

Due to the rapid development of text generation models, people increasingly often encounter texts that may start out as written by a human but then continue as machine-generated results of large language models. Detecting the boundary between human-written and machine-generated parts of such texts is a very challenging problem that has not received much attention in literature. In this work, we consider and compare a number of different approaches for this artificial text boundary detection problem, comparing several predictors over features of different nature. We show that supervised fine-tuning of the RoBERTa model works well for this task in general but fails to generalize in important cross-domain and cross-generator settings, demonstrating a tendency to overfit to spurious properties of the data. Then, we propose novel approaches based on features extracted from a frozen language model's embeddings that are able to outperform both the human accuracy level and previously considered baselines on the Real or Fake Text benchmark. Moreover, we adapt perplexity-based approaches for the boundary detection task and analyze their behaviour. We analyze the robustness of all proposed classifiers in cross-domain and cross-model settings, discovering important properties of the data that can negatively influence the performance of artificial text boundary detection algorithms

Discussion About the Book by Krausz Tamás “The Fate of Ideas During the USSR History and After...”

N.E. Vashkau in the essay “On the way to the dialogue of national historiographies” notes the importance of historical memory, interaction within the framework of the intercultural dialogue of historiographies. A.A. German, in solidarity with some of T. Kraus’ views on the historical memory of the Second World War, starts a polemic with him on a number of problems related to the theory, history and practice of the creation, development and fall of Soviet state socialism. T.B. Ivanova (section “Historical memory forecasting the future”) focuses on self-government as an instrument of social emancipation as a direction to develop the social structure, which T. Kraus pays special attention to in theory and political activity. The author pays attention to the wide information and evidence base offered by T. Kraus to prove the value of this idea every time for the next social reconstruction. E.F. Krinko in the section “Soviet history in a Marxist reading: Tamas Kraus on revolution, socialism, war and other issues” notes that the publication of the book provides us with a deep understanding about the Hungarian historian views basing on the denial of capitalism with its ideals of individualism and private property and commitment to the socialist idea. He emphasizes that T. Kraus rejects both the application of the theory of totalitarianism to Soviet history due to its limited research potential, and the apologetics of Soviet man and state socialism. S.G. Sidorov focused on the second section of T. Kraus’ book “War and Genocide. Historical facts and the politics of memory”, in which the author gives answers to important questions: who is responsible for the war; whether it is possible to compare the Nazi Germany with the USSR as well as GULAG and Auschwitz; who is guilty of civilians genocide and others. Sidorov has come to the conclusion that the application of “his methodological conviction – the third way” actually led the author to estimates that are close to many ones given by modern Russian historians, and allowed him to reasonably and fairly criticize the views on World War II, the Soviet period of Russian history prevailing today in Hungary and in the West

Secondary structures on the friction surface of diamond-like coating

Peculiarities of the formation of secondary structures on the surface of a diamond-like coating are studied on the example of a friction contact between a steel ball and a diamond-like coating. The friction surface was examined in various areas; the zone of wear products (the boundary of the friction track) and the original surface outside the friction area. It is shown that secondary structures with a high content of iron, nickel, manganese, chromium, and oxygen are characteristic of areas with the highest wear resistance. Such secondary structures are formed because of the intense interaction of the diamond-like coating with the steel of the ball during dry friction