Horia-Nicolai L. Teodorescu

Complex signal generators based on capacitors and on piezoelectric loads

Abstract: We briefly analyze and demonstrate several nonlinear signal generators, according to the principles proposed in [1]. These systems apparently should not oscillate, because they include only capacitors in the positive feedback loops. However, the design attempted to make use of the well-known parasitic elements of the capacitors to create a selective feedback loop with physical capacitors only. The use of the resonant (piezoelectric) load adds a new potential mode of oscillation. The design aimed to make achievable as many as possible frequency points where oscillation modes ay exist, against the rather common belief that a single oscillation mode can be supported at one time in electronic oscillators. For this purpose, variable, independent gains have been provided to the positive feedback loops that correspond to the various modes in the circuit. We describe the schemes, briefly analyze their behavior, show simulation and experimental results, and discuss potential uses. The paper is largely based on [1].

Survey of IC&T in Disaster Mitigation and Disaster Situation Management

This chapter serves as an introduction to the topic of the volume and sets the framework of the discussion. It is largely a review and synthesis of the literature, also including some personal suggestions and conclusions. It is a working paper in many aspects, where the term working paper is used in the sense of draft of the whole volume as well as an article intended to elicit feedback and discussions in the other chapters. This chapter also serves as a partial analysis of the literature. In the first section of the chapter, we list the roles of IT&C in disaster situations, review some of the international and national regulations on the subject, and plead for specific regulations regarding IT for disaster mitigation. The second part emphasizes the various aspects of disasters and the association with the design of specific IT means. The third part addresses resilience and robustness of the society and of the IT systems in disaster circumstances and the roles of IT means in improving disaster resilience.

Emergency-Related, Social Network Time Series: Description and Analysis

Emergencies and disasters produce a vast traffic on the social networks (SNs). Monitoring this traffic for detection of emergency situations reported by the public, for rapid intervention and for emergency consequences mitigation, is possible and useful. This article summarizes the results presented in a series of previous papers and brings new data evidence. We describe the specific traffic on social networks produced by several emergency situations and analyze the related time series. These time series are found to present a good picture of the situation and have specific properties. We suggest a method for the analysis of SN-related time series with the aim of establishing correlations between characteristics of the disaster and the SN response. The method may help the prediction of the dimension of the emergency situations and for forecasting needs and measures for relief and mitigation. Time series of real data (situation time series) are exemplified. The take-away from this article is that the SN content must be deeper statistically analyzed to extract more significant and reliable information about the social and external processes in disasters and use learned correlations for prediction and forecasting. This paper heavily relies on previous works of the author and reproduces several of the idea, sometimes ad verbatim, from those papers.

Improved Speech Synthesis Using Fuzzy Methods

The paper presents theoretical support for and describes the use of a fuzzy paradigm in implementing a TTS system for the Romanian language, employing a rule-based formant synthesizer. In the framework of classic TTS systems, we propose a new approach in order to improve formant trace computation, aiming at increasing synthetic speech perceptual quality. A fuzzy system is proposed for solving the problem of the phonemes that are prone to multi-definitions in rule-based speech synthesis. In the introductory section, we briefly present the background of the problem and our previous results in speech synthesis. In the second section, we deal with the problem of the context-dependent phonemes at the letter-to-sound module level of our TTS system. Then, we discuss the case of the phoneme /l/ and the solution adopted to define it for different contexts. A fuzzy system is associated with each parameter (denoted F1 and F2) to implement the results of the complete analysis of the phoneme /l/ behavior. The knowledge used in implementing the fuzzy module is acquired by natural speech analysis. In the third section, we exemplify the computation of the synthesis parameters F1 and F2 of the phoneme /l/ in the context of the two syllable sequences. The parameter values are contrasted with those obtained from the spectrogram analysis of the natural speech sequences. The last section presents the main conclusions and further research objectives.

Intelligent clothes with a network of painted sensors

Based on a movement sensor introduced in a companion paper, a system for monitoring the movements of a person is presented. The system comprises a set of capacitive sensors printed on the clothes and the capacitance measuring circuits. The network is described and experimental results are illustrated and discussed.

On the responses of social networks' to external events

The paper reviews and complements the knowledge on the social network responses to brief duration events such as earthquakes, attacks, and aviation crashes. The main question asked are (i) if the number of posts related to such events is a credible source of information for assessing the number of people affected, and (ii) if the early information obtained from the momentary number of posts can be used to derive the further dynamics of the response of the social network to the event. Limits of the use of social networks responses for the above purposes are emphasized.

Defining resilience using probabilistic event trees

The concept of resilience and various aspects related to resilience enhancement and resilience calculus are addressed in the context of the broader theme of reliability and disaster mitigation. A definition of resilience is proposed, based on the assessment of event trees and the statistical determination of risks. Essentially, we apply standard probabilistic models with conditional probabilities, event trees and fault trees, where faults are not limited to technological ones, but cover lack of personnel as well, to define the resilience in a systematic manner. An essential aspect of the approach is the estimation of the probability of recovery in a specified time frame. The time to recovery and the level of recovery play key roles in the definition. The main assumptions underlying the calculations are discussed. A synthetic resilience indicator is introduced to offer a short, easy to grasp clue on the resilience level, with the aim to facilitate planning for resilience. An analysis methodology is suggested under general conditions, and several examples of applications are given.

Textile-, conductive paint-based wearable devices for physical activity monitoring

The paper addresses two issues: the definition of a Global Activity (GlA) index for the physical activity of persons, and the development of a sensor on textile substrate and of the related front end circuitry for destined to health monitoring. Preliminary experimental results are reported.

Surface Potential Versus Electric Field Measurements Used to Characterize the Charging State of Nonwoven Fabrics

Surface potential and electric field measurement techniques are widely used for the investigation of the corona charging of dielectric surfaces in a wide range of industry applications. The aim of this paper is to estimate which of these techniques are the most appropriate for characterizing the charging state of nonwoven fibrous dielectrics and point out the “noise factors” that might distort the results of the measurements. The experiments were performed on samples of nonwoven polypropylene sheets, in contact with or at a well-defined distance from a grounded plane electrode. The effect of the variability of the position of the probes with respect to the samples was also investigated. Several recommendations have been formulated regarding the use of these techniques for monitoring the charging state of nonwoven fabrics in industry applications.

Statistical characteristics of the formants of the Romanian vowels in emotional states

We investigate the influence of the emotions expressed by female and male speakers on the formants of the vowels in the Romanian language. The main conclusions are that the formant F4 is not significantly modified by the expressed emotion; the pitch is significantly increased for joy in all vowels; the pitch is slightly decreased under sadness, and that the change in statistic distribution is quite large in all cases (vowels and states).