Horia-Nicolai Teodorescu

The article extends the theoretical and applicative analysis of Zipf’s law. We are concerned with a set of properties of Zipf’s law that derive directly from the power law expression and from the discrete nature of the objects to which the law is applied, when the objects are words, lemmas, and the like. We also search for variations of Zipf’s law that can help explain the noisy results empirically reported in the literature and the departures of the empirically obtained nonlinear graph from the theoretical linear one, with the variants analyzed differing from Mandelbrot and lognormal distributions. A problem of interest that we deal with is that of mixtures of populations obeying Zipf’s law. The last problem has relevance in the analysis of texts with words with various etymologies. Computational aspects are also addressed.

The paper pertains to the field of opinion mining on social networks in view of decision-making. It was designed to determine the effect of the energy crises on the socio-ethical and ethical worries and concerns related to the role of Information and Communication Technology (ICT) in the crisis, as reflected on Twitter. Knowing public opinions during crises is a key component of decision-making. Other purposes include the determination of the perception of the correlations between these categories of concerns and the determination of specificities of distributions of such perceptions, as represented by words. A mixture of tools from lexical, topical, and semantical analysis were applied for generating the bag of words and for analyzing a set of tweets collected during the initial stage of an energy crisis, with special emphasis to coherence indices. The results confirm that energy crises may be associated with such concerns, as expected, but the association probability is low for the 2022 energy crisis, indicating at least a partial success of the mitigation decisions of the respective authorities. Some surprising relationships also occurred from the study. The paper is dedicated to Acad. Florin Gheorghe Filip, at the 75th anniversary.

Prof. Dzitac used to say, ‘The mathematics of fuzzy systems is not fuzzy’. We discuss several limits and potential errors in the design of fuzzy logic systems and how they can be corrected or avoided. Examples from the literature are presented.

Designing alarms for medical equipment may seem easy, but the standards' requirements combined with the nonlinearity of the acoustic transducers, with the difficulties of assessing the acoustic impedance of the transducer chamber, and with criteria such as power consumption and efficiency of the electric to acoustic conversion make the design challenging. We systematically analyze the related problems and discuss design solutions specifically for wearable alarms; examples are shown for an implemented alarm with usual driver. The main focus is on the power efficiency and the sound spectra of these alarms.

Zadeh's (min-max, standard) fuzzy logic and various other logics are commutative, but natural language has nuances suggesting the premises are not equal, with premises contributing to the conclusion according to their prominency. Therefore, we suggest variants of salience-based, noncommutative and non-associative fuzzy logic (prominence logic) that may better model natural language and reasoning when using linguistic variables. Noncommutative fuzzy logics have several theoretical and applicative motivations to be used as models for human inference and decision making processes. Among others, asymmetric relations in economy and management, such as buyer-seller, provider-user, and employer-employee are noncommutative relations and induce noncommutative logic operations between premises or conclusions. A class of noncommutative fuzzy logic operators is introduced and fuzzy logic systems based on the corresponding noncommutative logics are described and analyzed. The prominence of the operators in the noncommutative operations is conventionally assumed to be determined by their precedence. Specific versions of noncommutative logics in the class of the salience-based, noncommutative logics are discussed. We show how fuzzy logic systems may be built based on these types of logics. Compared with classic fuzzy systems, the noncommutative fuzzy logic systems have improved performances in modeling problems, including the modeling of economic and social processes, and offer more flexibility in approximation and control. Applications discussed include management and engineering problems and issues in the field of firms’ ethics or ethics of AI algorithms.

We are reporting on lessons learned from an e-contest for students held during the current pandemic. We compare the e-contest with the 10 previous editions of the same but face-to-face contest. While apparently the competition did not suffer because of being a virtual one, some disadvantages were noted. The main conclusions are: the basic interconnectivity means arise no serious technical issue, but the interconnectivity is more limited than the face-to-face one; online jury-competitors interactivity is poorer than face-to-face interactivity; human factors, higher uncertainties in the organization process, and less time to spend in the process for the local organizers are major limiting factors; concerns on the participation and evaluation fairness are higher; involuntary gender discrimination seems lower, but persists; there are serious concerns related to privacy, including differential privacy; some peculiarities of the presented topics and of the evaluation process emerged, but it is unclear if they are related to the online nature of the competition, to the extra stress on the participants during the pandemic, to other factors, or are random. While some conclusions may be intimately related to the analyzed case, some are general enough for being worth to other online competitions.

Speech and language technologies are parts of AI family of tools and methods that already have an economic impact; they are assumed to extend that impact in the near future. We analyze the contributions of several average and small central European countries to these fields in terms of papers published. We compare these contributions with those of France and Germany and establish relationships between the efficiency measured by scientific publications between subfields of speech and language technologies. We find that Czech Republic is more efficient in terms of papers per inhabitant even than Germany. Czech Republic excels too when the number of papers is divided by the population of tertiary education. Also, we find interesting strong and low correlations between subdomains.

Voice and speech communication is a major topic covering simultaneously ’communication’, ’control’ (because it often involves control in the coding algorithms), and ’computing’ - from speech analysis and recognition, to speech analytics and to speech coding over communication channels. While fuzzy logic was specifically con- ceived to deal with language and reasoning, it has yet a limited use in the referred field. We discuss some of the main current applications from the perspective of half a century since fuzzy logic inception.