Neuronal avalanches differ from wakefulness to deep sleep - evidence from intracranial depth recordings in humans

Neuronal activity differs between wakefulness and sleep states. In contrast, an attractor state, called self-organized critical (SOC), was proposed to govern brain dynamics because it allows for optimal information coding. But is the human brain SOC for each vigilance state despite the variations in neuronal dynamics? We characterized neuronal avalanches – spatiotemporal waves of enhanced activity - from dense intracranial depth recordings in humans. We showed that avalanche distributions closely follow a power law – the hallmark feature of SOC - for each vigilance state. However, avalanches clearly differ with vigilance states: slow wave sleep (SWS) shows large avalanches, wakefulness intermediate, and rapid eye movement (REM) sleep small ones. Our SOC model, together with the data, suggested first that the differences are mediated by global but tiny changes in synaptic strength, and second, that the changes with vigilance states reflect small deviations from criticality to the subcritical regime, implying that the human brain does not operate at criticality proper but close to SOC. Independent of criticality, the analysis confirms that SWS shows increased correlations between cortical areas, and reveals that REM sleep shows more fragmented cortical dynamics

A Robust Method for Detecting Interdependences: Application to Intracranially Recorded EEG

We present a measure for characterizing statistical relationships between two time sequences. In contrast to commonly used measures like cross-correlations, coherence and mutual information, the proposed measure is non-symmetric and provides information about the direction of interdependence. It is closely related to recent attempts to detect generalized synchronization. However, we do not assume a strict functional relationship between the two time sequences and try to define the measure so as to be robust against noise, and to detect also weak interdependences. We apply our measure to intracranially recorded electroencephalograms of patients suffering from severe epilepsies.Comment: 29 pages, 5 figures, paper accepted for publication in Physica

A novel method for determining fixed running time in operating electric train tracking optimal speed profile

Tracking the optimal speed profile in electric train operation has been proposed as a potential solution for reducing energy consumption in electric train operation, at no cost to improve infrastructure of existing Metro lines as well. However, the optimal speed profile needs to meet fixed running time. Therefore, this paper focuses on a new method for determining the fixed running time complied with the scheduled timetable when trains track the optimal speed profile. The novel method to ensure the fixed running time is the numerical-analytical one. Calculating accelerating time ta, coasting time tc, braking time tb via values of holding speed vh, braking speed vb of optimal speed profile with the constraint condition: the running time equal to the demand time. The other hands, vh and vb are determined by solving nonlinear equations with constraint conditions. Additionally, changing running time suit for each operation stage of metro lines or lines starting to conduct schedules by the numerical-analytical method is quite easy. Simulation results obtained for two scenarios with data collected from electrified trains of Cat Linh-Ha Dong metro line, Vietnam show that running time complied with scheduled timetables, energy saving by tracking optimal speed profile for the entire route is up to 8.7%, if the running time is one second longer than original time, energy saving is about 11.96%

Mergers and Acquisitions in Sin Industries

Ph. D. ThesisMergers and acquisitions (M&A) have the potential to generate value for firms and their shareholders by gaining synergy from targets. However, the empirical evidence suggests M&A destroy firms’ value and shareholders’ wealth instead. The reason is that the acquirers are overwhelmingly motivated by value-decreasing motives (e.g., market-timing, empire building). The sin industries (e.g., tobacco, alcohol, and casino) are different from other industries due to their harmfulness and devastative consequences to society. Because of this characteristic, sin industries are stigmatized and neglected by society and investors. This negative attitude towards sin industries poses a significant negative impact on sin businesses (e.g., elevating the cost of capital, see Hong and Kacperczyk, 2009). Accordingly, it is essential for sin firms to improve their images. Shedding light on this behaviour, this thesis examines performance and motives of sin M&As in the G20 countries from 1993 to 2017. We show that sin firms try to improve their images by making value-increasing acquisitions. In relative terms, the sin acquirer market returns are more favourable than non-sin acquirer returns. Moreover, prior literature shows evidence that societal attitudes towards sin industries differ across countries. Classifying the G20 sample into high and low social norm countries, we extended prior literature by examining how social norms impact sin and non-sin firm M&As. We explore three angles of sin mergers and acquisitions: short-term market reaction to M&A announcements, long-term performance after acquisitions, and the motives behind M&A decisions. In the first empirical chapter, we find that the sin acquirer cumulative abnormal returns (CAR) at M&A announcements are more favourable than non-sin acquirer CARs. The difference in CARs across sin and non-sin acquirers is further elevated in high relative to lowsocial-norm countries, where people are less concerned about the negative consequences of sin industries than other countries. In the second empirical chapter, we find that the long-term operating performance of sin acquirers are not improved. However, the sin acquirer’s shareholders gain significantly positive returns in the long-term after acquisitions. Moreover, the sin acquirer returns are more favourable than non-sin acquirer returns. Interestingly, the difference in returns across sin and non-sin acquirers is further elevated in high relative to low-social-norm countries. In the last empirical chapter, we find that sin acquirers are inspired by market-timing and synergy motives. However, sin acquirers are less motivated by market-timing than non-sin acquirers. The difference in market-timing motive between sin acquirers and non-sin acquirers iii is greater in high-social-norm countries, where people are more concerned about the negative effect of the sin industries In conclusion, we find evidence that the sin firms improve their image by involving in better M&A deals than non-sin acquirers. As a result, the market reactions to M&A announcements of sin acquirers are more favourable than for non-sin acquirers. As there is no differential impact on operating performance, the more favourable return of sin acquirers likely derives from their better motives (i.e., less market-timing). Interestingly, the difference in market performance and motives across sin and non-sin acquirers is further elevated in high relative to low-social norm countries

Radial basis function neural network control for parallel spatial robot

The derivation of motion equations of constrained spatial multibody system is an important problem of dynamics and control of parallel robots. The paper firstly presents an overview of the calculating the torque of the driving stages of the parallel robots using Kronecker product. The main content of this paper is to derive the inverse dynamics controllers based on the radial basis function (RBF) neural network control law for parallel robot manipulators. Finally,  numerical simulation of the inverse dynamics controller for a 3-RRR delta robot manipulator is presented as an illustrative example