Buses of Cuernavaca - an agent-based model for universal random matrix behavior minimizing mutual information

The public transportation system of Cuernavaca, Mexico, exhibits random matrix theory statistics [1]. In particular, the fluctuation of times between the arrival of buses on a given bus stop, follows the Wigner surmise for the Gaussian Unitary Ensemble. To model this, we propose an agent-based approach in which each bus driver tries to optimize his arrival time to the next stop with respect to an estimated arrival time of his predecessor. We choose a particular form of the associated utility function and recover the appropriate distribution in numerical experiments for a certain value of the only parameter of the model. We then investigate whether this value of the parameter is otherwise distinguished within an information theoretic approach and give numerical evidence that indeed it is associated with a minimum of averaged pairwise mutual information.Comment: numerical analysis extende

Statistics for Tail Processes of Markov Chains

At high levels, the asymptotic distribution of a stationary, regularly varying Markov chain is conveniently given by its tail process. The latter takes the form of a geometric random walk, the increment distribution depending on the sign of the process at the current state and on the flow of time, either forward or backward. Estimation of the tail process provides a nonparametric approach to analyze extreme values. A duality between the distributions of the forward and backward increments provides additional information that can be exploited in the construction of more efficient estimators. The large-sample distribution of such estimators is derived via empirical process theory for cluster functionals. Their finite-sample performance is evaluated via Monte Carlo simulations involving copula-based Markov models and solutions to stochastic recurrence equations. The estimators are applied to stock price data to study the absence or presence of symmetries in the succession of large gains and losses

Hand posture recognition using modified Ensemble of Shape Functions and Global Radius-based Surface Descriptor

This paper presents an approach to recognition of static hand gestures based on data acquired from 3D cameras and point cloud descriptors: Ensemble of Shape Functions and Global Radius-based Surface Descriptor. We describe the recognition algorithm consisting of: hand segmentation, noise removal and downsampling of point cloud, dividing point cloud bounding box to cells, feature extraction and normalization, gesture classification. Modifications of the descriptors are proposed in order to increase hand posture recognition rates and decrease quantity of used features as well as computational cost of the algorithm. The experiments performed on four challenging datasets using cross-validation tests prove the usefulness of our approach

Zbawczy wymiar samotności oraz jej konsekwencje dla chrześcijanina

Solitude for Christians is not a burden but an indispensable dimension ofmaturing to sanctity. It results from the life of Christ who did not only experience loneliness in the desert and on the cross, but made it something necessary. In solitude, the cross of Christ is shown as openness to all in the realization of love. Connecting them with the solitude of Christ it is easier to bear al kindly of difficult experiences inconveniences as well as to help those who cannot cope with them

Universal shocks in the Wishart random-matrix ensemble - a sequel

We study the diffusion of complex Wishart matrices and derive a partial differential equation governing the behavior of the associated averaged characteristic polynomial. In the limit of large size matrices, the inverse Cole-Hopf transform of this polynomial obeys a nonlinear partial differential equation whose solutions exhibit shocks at the evolving edges of the eigenvalue spectrum. In a particular scenario one of those shocks hits the origin that plays the role of an impassable wall. To investigate the universal behavior in the vicinity of this wall, a critical point, we derive an integral representation for the averaged characteristic polynomial and study its asymptotic behavior. The result is a Bessoid function.Comment: 7 pages, 2 figure

Polityka pamięci w japońsko-chińskich stosunkach dyplomatycznych

The conflict concerning historical events between Japan and China is now more visible than ever before – once again the disputes over Senkaku/ Diaoyu islands have awakened the ghosts of the past and undermined Japanese-Chinese bilateral relations. The major problems in the politics of memory between those two Asian countries are the rape of Nanking, the content of Japanese textbooks and officials’ visits in Yasukuni shrine. While the tensions are rising, Japan and China struggle to establish historical facts and present their interpretations to the society

Burgers-like equation for spontaneous breakdown of the chiral symmetry in QCD

We link the spontaneous breakdown of chiral symmetry in Euclidean QCD to the collision of spectral shock waves in the vicinity of zero eigenvalue of Dirac operator. The mechanism, originating from complex Burger's-like equation for viscid, pressureless, one-dimensional flow of eigenvalues, is similar to recently observed weak-strong coupling phase transition in large $N_c$ Yang-Mills theory. The spectral viscosity is proportional to the inverse of the size of the random matrix that replaces the Dirac operator in the universal (ergodic) regime. We obtain the exact scaling function and critical exponents of the chiral phase transition for the averaged characteristic polynomial for $N_c \ge3$ QCD. We reinterpret our results in terms of known properties of chiral random matrix models and lattice data.Comment: 12 page

Universal shocks in the Wishart random matrix ensemble - 1

We show that the derivative of the logarithm of the average characteristic polynomial of a diffusing Wishart matrix obeys an exact partial differential equation valid for an arbitrary value of N, the size of the matrix. In the large N limit, this equation generalizes the simple Burgers equation that has been obtained earlier for Hermitian or unitary matrices. The solution through the method of characteristics presents singularities that we relate to the precursors of shock formation in fluid dynamical equations. The 1/N corrections may be viewed as viscous corrections, with the role of the viscosity being played by the inverse of the doubled dimension of the matrix. These corrections are studied through a scaling analysis in the vicinity of the shocks, and one recovers in a simple way the universal Bessel oscillations (so-called hard edge singularities) familiar in random matrix theory.Comment: 9 page

COPD in Poland – risk factor and epidemiology

Chronic obstructive pulmonary disease (COPD) falls under the category of civilization diseases. According to World Health Organization, its burden is expected to increase in the following decades, mainly due to constant exposition to the risk factors, population growth and ageing, to become the third most frequent cause of death until 2030. According to the guidelines of the Global Initiative for Chronic Obstructive Lung Disease (GOLD) from 2015, COPD can be prevented and successfully treated. Despite the serious problem that is COPD, in many countries the data on this disease is insufficient. The most important risk factor leading to COPD that can be modified is smoking tobacco, the habit that is still popular among the adults. The knowledge of the risk factors and their elimination, as well as leading a healthy lifestyle and preference towards health behaviour that helps reducing the advancement of the disease should therefore become the basis for preventing COPD

A Sense of the Role and Value of Non-Formal Education in the Opinion of Students Participating in Interactive Workshops

The paper presents the results that relate to the opinion of the role and value of non-formal education using interactive workshops of students taking part in a series of meetings organised by the University of Rzeszow. The main method was the diagnostic survey carried out using the CAPI technique (Computer Assisted Personal Interview). Today, it is extremely important to support the traditional formal education with its other forms. As shown in the results, students expect schools to organise non-formal education, which gives them the opportunity to develop interests that stimulate learning. Based on the presented results, we can also say that activities using interactive workshops bring very satisfactory learning outcomes, so it is worth supporting and implementing similar ways of education.The paper presents the results that relate to the opinion of the role and value of non-formal education using interactive workshops of students taking part in a series of meetings organised by the University of Rzeszow. The main method was the diagnostic survey carried out using the CAPI technique (Computer Assisted Personal Interview). Today, it is extremely important to support the traditional formal education with its other forms. As shown in the results, students expect schools to organise non-formal education, which gives them the opportunity to develop interests that stimulate learning. Based on the presented results, we can also say that activities using interactive workshops bring very satisfactory learning outcomes, so it is worth supporting and implementing similar ways of education