Development of an Algorithm for Multicriteria Optimization of Deep Learning Neural Networks

Nowadays, machine learning methods are actively used to process big data. A promising direction is neural networks, in which structure optimization occurs on the principles of self-configuration. Genetic algorithms are applied to solve this nontrivial problem. Most multicriteria evolutionary algorithms use a procedure known as non-dominant sorting to rank decisions. However, the efficiency of procedures for adding points and updating rank values in non-dominated sorting (incremental non-dominated sorting) remains low. In this regard, this research improves the performance of these algorithms, including the condition of an asynchronous calculation of the fitness of individuals. The relevance of the research is determined by the fact that although many scholars and specialists have studied the self-tuning of neural networks, they have not yet proposed a comprehensive solution to this problem. In particular, algorithms for efficient non-dominated sorting under conditions of incremental and asynchronous updates when using evolutionary methods of multicriteria optimization have not been fully developed to date. To achieve this goal, a hybrid co-evolutionary algorithm was developed that significantly outperforms all algorithms included in it, including error-back propagation and genetic algorithms that operate separately. The novelty of the obtained results lies in the fact that the developed algorithms have minimal asymptotic complexity. The practical value of the developed algorithms is associated with the fact that they make it possible to solve applied problems of increased complexity in a practically acceptable time. Doi: 10.28991/HIJ-2023-04-01-011 Full Text: PD

Motor Cortex Hyperexcitability, Neuroplasticity, and Degeneration in Amyotrophic Lateral Sclerosis

Neuronal hyperexcitability is a well-known phenomenon in amyotrophic lateral sclerosis and other neurodegenerative diseases. The use of transcranial magnetic stimulation in clinical and research practice has recently made it possible to detect motor cortex hyperexcitability under clinical conditions. Despite numerous studies, the mechanisms and sequelae of the development of hyperexcitability still have not been completely elucidated. In this chapter, we discuss the possibilities for detecting motor cortex hyperexcitability in patients with amyotrophic lateral sclerosis using transcranial magnetic stimulation. The potential relationship between hyperexcitability and neuronal degeneration or neuroplasticity processes is discussed using the data obtained by navigated transcranial magnetic stimulation and neuroimaging data, as well as the data of experimental studies

Higher-Derivative Two-Dimensional Massive Fermion Theories

We consider the canonical quantization of a generalized two-dimensional massive fermion theory containing higher odd-order derivatives. The requirements of Lorentz invariance, hermiticity of the Hamiltonian and absence of tachyon excitations suffice to fix the mass term, which contains a derivative coupling. We show that the basic quantum excitations of a higher-derivative theory of order 2N+1 consist of a physical usual massive fermion, quantized with positive metric, plus 2N unphysical massless fermions, quantized with opposite metrics. The positive metric Hilbert subspace, which is isomorphic to the space of states of a massive free fermion theory, is selected by a subsidiary-like condition. Employing the standard bosonization scheme, the equivalent boson theory is derived. The results obtained are used as a guideline to discuss the solution of a theory including a current-current interaction.Comment: 23 pages, Late

DIAGNOSTIC VALUE OF THE DEJA VU PHENOMENON IN THE CLINICAL PICTURE OF GLIAL BRAIN TUMORS

In growing glial tumors, epileptic seizures are the first and only symptom of the disease in more than a third of cases. The seizure is commonly characterized by only psychopathological disorders that are frequently ignored by both patients and physicians. The deja vu (DV) phenomenon may be one of such symptoms. Its specific feature is that it occurs in both healthy individuals and patients with various brain pathologies. This investigation was undertaken to study the implication of the DV phenomenon in the clinical picture of glial brain tumors (GBT). One hundred and sixty-one subjects (mean age 29,2±6,4 years; males 47%), including 129 healthy individuals and 32 patients with GBT, were examined. In the clinical picture of GBT with seizures, DV is a common symptom that is encountered in the involvement of predominantly the right temporal lobe and accompanied by generalized convulsive attacks and olfactory hallucinations. DV in GBT occurs more than once daily; its duration is a few (as many as 5) minutes; DV is characterized by a negative emotional tinge and attended by fear

Exact Pair Production Rate for a Smooth Potential Step

We derive the exact rate of pair production of oppositely charged scalar particles by a smooth potential proportional to tanh kz in three dimensions. As a check we recover from this the known results for an infinitely sharp step as well as for a uniform electric field.Comment: Removed the labels and improved the pape

Increased motor cortex excitability during motor imagery in brain-computer interface trained subjects

Background: Motor imagery (MI) is the mental performance of movement without muscle activity. It is generally accepted that MI and motor performance have similar physiological mechanisms. Purpose: To investigate the activity and excitability of cortical motor areas during MI in subjects who were previously trained with an MI-based brain-computer interface (BCI). Subjects and Methods: Eleven healthy volunteers without neurological impairments (mean age, 36 years; range: 24–68 years) were either trained with an MI-based BCI (BCI-trained, n = 5) or received no BCI training (n = 6, controls). Subjects imagined grasping in a blocked paradigm task with alternating rest and task periods. For evaluating the activity and excitability of cortical motor areas we used functional MRI and navigated transcranial magnetic stimulation (nTMS). Results: fMRI revealed activation in Brodmann areas 3 and 6, the cerebellum, and the thalamus during MI in all subjects. The primary motor cortex was activated only in BCI-trained subjects. The associative zones of activation were larger in non-trained subjects. During MI, motor evoked potentials recorded from two of the three targeted muscles were significantly higher only in BCI-trained subjects. The motor threshold decreased (median = 17%) during MI, which was also observed only in BCI-trained subjects. Conclusion: Previous BCI training increased motor cortex excitability during MI. These data may help to improve BCI applications, including rehabilitation of patients with cerebral palsy.Web of Science7art. no. 0016

Quark mass correction to the string potential

A consistent method for calculating the interquark potential generated by the relativistic string with massive ends is proposed. In this approach the interquark potential in the model of the Nambu--Goto string with point--like masses at its ends is calculated. At first the calculation is done in the one--loop approximation and then the variational estimation is performed. The quark mass correction results in decreasing the critical distance (deconfinement radius). When quark mass decreases the critical distance also decreases. For obtaining a finite result under summation over eigenfrequencies of the Nambu--Goto string with massive ends a suitable mode--by--mode subtraction is proposed. This renormalization procedure proves to be completely unique. In the framework of the developed approach the one--loop interquark potential in the model of the relativistic string with rigidity is also calculated.Comment: 34 pages, LATE

Predictive accuracy of cardiac risk indices for cardiovascular complications in patients undergoing noncardiac surgery

Objective: To compare predictive accuracy of the American Society of Anesthesiologists (ASA) score and various cardiac risk indices for perioperative cardiovascular (CV) complications in patients undergoing noncardiac surgery.Materials and methods: We examined 243 patients (148 men and 95 women) aged 45 to 84 (66 [60-71] years) prior to their elective oncological and vascular surgery. We assessed patients using the ASA physical status classification system, Revised Cardiac Risk Index (RCRI), Gupta Myocardial Infarct or Cardiac Arrest (MICA) calculator, and Khoronenko cardiac risk index and analyzed perioperative CV complications.Results: We detected complications in 30 (12.3%) patients, with 3 (1.24%) of them having 2 concomitant CV complications. One death (0.41%) was registered. The MICA risk calculator had the highest predictive value (AUC ROC = 0.753). Risk scores over 0.95% discriminated patients with perioperative CV complications with sensitivity and specificity of 73.3% and 67.45%, respectively.Conclusions: We recommend using the MICA risk calculator to predict perioperative CV complications following elective oncological and vascular surgery