TESTING AND DEBUGGING OF EMBEDDED COMPUTING SYSTEMS BASED ON LEVEL MODELS

Subject of Research.The paper deals with the problem of organization of testing and debugging in complex (full stack) projects of embedded computing systems with heterogeneous structure. The work is aimed at unified formal method development to organize testing and debugging that is applicable to a wide range of embedded systems and invariant to their implementation. The conclusion is drawn about the prospects of using level models of embedded systems representation as a method of unified modeling of complex projects of embedded systems. Method. To develop the method, we used the abstractions of the HLD-methodology of embedded systems design, the "model-process-processor" architectural style and methods of set theory. Main Results. The embedded systems testing and debug method based on level models is developed. We enhanced the "model-process-processor" architectural style, as a part of the method, for a more accurate description of the virtualization relations. The method of embedded systems multi-level testing is developed, which allows describing the test environment at different phases of embedded systems creation in the same style, provides the formalization of the concepts of testing, verification and validation from the embedded systems level representation point of view. Examples of description of multi-level embedded systems using the developed method are given. Practical Relevance. The method provided documentation techniques of embedded systems test environments at different phases of their creation, ways to organize testing, verification, validation and debugging in complex projects of embedded systems.The proposed approach increases requirements control efficiency in the embedded systems projects owing to the end-to-end and transparent project representation as a whole and formalization of the testing and debugging procedures

Structure and magnetism of copper substituted cobalt ludwigite Co₃O₂BO₃

The single crystals Co₃O₂BO₃ with partial (4%) substitution of Co by Cu ions were synthesized by the flux technique. X-ray diffraction and magnetic properties investigations were carried out. The x-ray diffraction meas-urements have shown that Cu clearly prefers only one from four nonequivalent crystallographic positions with the smallest electric field gradient. The ferrimagnetic ordering near TN = 43 K and high magnetic hardness in this magnetic phase are similar to Co₃O₂BO₃. The small reduction of the effective magnetic moment was revealed under copper substitution

Hard X-ray magnetochiral dichroism in a paramagnetic molecular 4f complex

Magnetochiral dichroism (MΧD) originates in the coupling of local electric fields and magnetic moments in systems where a simultaneous break of space parity and time-reversal symmetries occurs. This magnetoelectric coupling, displayed by chiral magnetic materials, can be exploited to manipulate the magnetic moment of molecular materials at the single molecule level. We demonstrate herein the first experimental observation of X-ray magnetochiral dichroism in enantiopure chiral trigonal single crystals of a chiral mononuclear paramagnetic lanthanide coordination complex, namely, holmium oxydiacetate, at the Ho L(3)-edge. The observed magnetochiral effect is opposite for the two enantiomers and is rationalised on the basis of a multipolar expansion of the matter–radiation interaction. These results demonstrate that 4f–5d hybridization in chiral lanthanoid coordination complexes is at the origin of magnetochiral dichroism, an effect that could be exploited for addressing of their magnetic moment at the single molecule level

Using Redox-Active πbridging Ligand as a Control Switch of Intramolecular Magnetic Interactions

Intramolecular magnetic interactions in the dinuclear complexes [(tpy)­Ni­(tphz)­Ni­(tpy)]^<i>n</i>+ (<i>n</i> = 4, 3, and 2; tpy, terpyridine; tphz, tetrapyridophenazine) were tailored by changing the oxidation state of the pyrazine-based bridging ligand. While its neutral form mediates a weak antiferromagnetic (AF) coupling between the two <i>S</i> = 1 Ni­(II), its reduced form, tphz^•–, promotes a remarkably large ferromagnetic exchange of +214(5) K with Ni­(II) spins. Reducing twice the bridging ligand affords weak Ni–Ni interactions, in marked contrast to the Co­(II) analogue. Those experimental results, supported by a careful examination of the involved orbitals, provide a clear understanding of the factors which govern strength and sign of the magnetic exchange through an aromatic bridging ligand, a prerequisite for the rational design of strongly coupled molecular systems and high <i>T</i>_C molecule-based magnets

Совершенствование показателей работы автомобильного двигателя с непосредственным впрыскиванием бензина

Here are analyzed the problem questions which are connected with perspective working out of domestic automobile petrol engines of new generation with internal carburetion which stimulates necessity to search the means and the new technical decisions which can be suitable for domestic engine engineering. The method of developing automobile explosion engine performance of the given type has been suggested as an alternative variant, which is based on the use of hydrogen as a chemical reagent.Анализируются вопросы, связанные с перспективой разработки отечественных автомобильных бензиновых двигателей нового поколения с внутренним смесеобразованием, которые стимулируют необходимость поиска средств и новых технических решений, приемлемых для отечественного двигателестроения. В качестве альтернативного варианта предложен метод совершенствования показателей работы двигателя данного типа, основанный на использовании водорода в качестве химического реагента

Spin state crossover in Co3BO5

We have investigated the spin and oxidation states of Co in Co3BO5 using x-ray magnetic circular dichroism (XMCD) and dc magnetic susceptibility measurements. At low temperatures, XMCD experiments have been performed at the Co K-edge in Co3BO5 and Co2FeBO5 single crystals in the fully ferrimagnetically ordered phase. The Co (K-edge) XMCD signal is found to be related to the Co2+ magnetic sublattices in both compounds, providing strong experimental support for the low-spin (LS) Co3+ scenario. The paramagnetic susceptibility is highly anisotropic. An estimation of the effective magnetic moment in the temperature range 100-250 K correlates well with two Co2+ ions in the high-spin (HS) state and some orbital contribution, while Co3+ remains in the LS state. The crystal structure of the Co3BO5 single crystal has been solved in detail at the T range 296-703 K. The unit cell parameters and volume show anomalies at 500 and 700 K. The octahedral environment of the Co4 site strongly changes with heating. The generalized gradient approximation with Hubbard U correction calculations have revealed that, at low-temperatures, the system is insulating with a band gap of 1.4 eV, and the Co2+ ions are in the HS state, while Co3+ are in the LS state. At high temperatures (T > 700 K), the charge ordering disappears, and the system becomes metallic with all Co ions in 3d7 electronic configuration and HS state. © 2021 American Physical Society