Michael Grabchak

ORCID: 0000-0003-2547-0167
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About
Contact & Profiles
Research Areas
  • Stochastic processes and financial applications
  • Financial Risk and Volatility Modeling
  • Stochastic processes and statistical mechanics
  • Probability and Risk Models
  • Bayesian Methods and Mixture Models
  • Statistical Methods and Inference
  • Markov Chains and Monte Carlo Methods
  • Statistical Distribution Estimation and Applications
  • Advanced Statistical Process Monitoring
  • Complex Systems and Time Series Analysis
  • Market Dynamics and Volatility
  • Authorship Attribution and Profiling
  • Algorithms and Data Compression
  • Theoretical and Computational Physics
  • Nonlinear Differential Equations Analysis
  • Advanced Queuing Theory Analysis
  • Complex Network Analysis Techniques
  • Advanced Statistical Methods and Models
  • Teaching and Learning Programming
  • Experimental Learning in Engineering
  • Statistical Mechanics and Entropy
  • Human Mobility and Location-Based Analysis
  • Credit Risk and Financial Regulations
  • Mathematical Dynamics and Fractals
  • Monetary Policy and Economic Impact

University of North Carolina at Charlotte
2016-2025

National Research University Higher School of Economics
2016

University of North Carolina at Chapel Hill
2013

Cornell University
2010-2011

A common approach to simulating a Lévy process is truncate its shot-noise representation. We focus on subordinators and introduce the remainder process, which represents jumps that are removed by truncation. characterize when these processes self-similar show that, in case, they can be indexed parameter α∈(−∞,1). When α∈(0,1), correspond α-stable distributions, α=0, certain generalizations of Dickman distribution. Thus, distribution plays role 0-stable this context.

10.3390/math13060907 article EN cc-by Mathematics 2025-03-08

One of the major points contention in studying and modelling financial returns is whether or not variance finite infinite (sometimes referred to as Bachelier–Samuelson Gaussian world versus Mandelbrot stable world). A different formulation question asks how heavy tails are. The available empirical evidence can be, has been, interpreted more than one way. apparent paradox, which puzzled many a researcher, that appear become less for frequent (e.g. monthly) daily) returns, phenomenon easily...

10.1080/14697680903540381 article EN Quantitative Finance 2010-07-15

Modern measures of diversity satisfy reasonable axioms, are parameterized to produce profiles, can be expressed as an effective number species simplify their interpretation, and come with estimators that allow one apply them real-world data. We introduce the generalized Simpson's entropy a measure investigate its properties. show it has many useful features used biodiversity. Moreover, unlike most commonly indices, unbiased estimators, which for sound estimation poorly sampled, rich communities.

10.1371/journal.pone.0173305 article EN public-domain PLoS ONE 2017-03-07

We extend the class of tempered stable distributions, which were first introduced in Rosiński (2007). Our new allows for more structure and variety tail behaviors. discuss various subclasses relations between them. To characterize possible tails, we give detailed results about finiteness moments. also necessary sufficient conditions tails to be regularly varying. This last part us domain attraction a particular distribution belongs.

10.1239/jap/1354716655 article EN Journal of Applied Probability 2012-12-01

In this letter, we introduce an estimator of Küllback-Leibler divergence based on two independent samples. We show that any finite alphabet, has exponentially decaying bias and it is consistent asymptotically normal. To explain the importance estimator, provide a thorough analysis more standard plug-in estimator. normal, but with infinite bias. Moreover, if modify to remove rare events cause become infinite, still decays at rate no faster than O(1/n). Further, extend our results estimating...

10.1162/neco_a_00646 article EN Neural Computation 2014-07-24

Abstract We propose a new methodology for testing the authorship of relatively small work compared with large body an author's cannon. Our approach is based on comparing entropy two samples. The difficulty lies in fact that known estimators tend to have bias even when sample size fairly large. To deal this, we suggest splitting larger into several parts length equal smaller work. then using these sub-samples simple non-parametric test. apply our test whether poem "Shall I Die?" which...

10.1080/09296174.2013.830551 article EN Journal of Quantitative Linguistics 2013-11-01

This paper serves a twofold purpose. First, unified perspective on diversity indices is introduced based an entropic basis. It shown that the class of all linear combinations basis, referred to as indices, covers wide range used in literature. Second, estimators for proposed and it these have rapidly decaying biases asymptotic normality.

10.1080/10485252.2016.1190357 article EN Journal of nonparametric statistics 2016-06-08

Zhang in 2012 introduced a nonparametric estimator of Shannon’s entropy, whose bias decays exponentially fast when the alphabet is finite. We propose methodology to estimate this estimator. then use it construct new entropy. Simulation results suggest that adjusted has significantly lower than many other commonly used estimators. consider both case finite and countably infinite.

10.3390/e15061999 article EN Entropy 2013-05-23

We give an explicit representation for the transition law of a tempered stable Ornstein–Uhlenbeck process and use it to develop rejection sampling algorithm exact simulation increments from this process. Our results apply general classes both univariate multivariate distributions contain number previously studied as special cases.

10.1080/00949655.2020.1714621 article EN Journal of Statistical Computation and Simulation 2020-01-21

Mobility models are crucial for the simulation and evaluation of protocols multihop wireless networks. However, most commonly used mobility do not reflect way humans actually move. This significantly affects reliability results. In this paper we introduce a new model called Smoothly Truncated Levy Walk (STLW), which is more realistic than standard that appear in literature. Its main innovations as follows. First, to take into account dependencies direction motion, it changes instead...

10.1109/pccc.2014.7017071 article EN 2014-12-01

We introduce a methodology for the simulation and parameter estimation of multivariate tempered stable distributions with an emphasis on bivariate case. Our approach is based approximation due to discretization spectral measure. It then applied two financial datasets related exchange rates. The first comprised rates between standard currencies, while second cryptocurrencies. results hold wide class infinitely divisible distributions.

10.1080/00949655.2021.1962878 article EN Journal of Statistical Computation and Simulation 2021-09-01

For a probability distribution $P$ on an at most countable alphabet $\mathcal{A}$, this article gives finite sample bounds for the expected occupancy counts $\mathbb{E}K_{n,r}$ and probabilities $\mathbb{E}M_{n,r}$. Both upper lower are given in terms of counting function $\nu$ $P$. Special attention is to case where bounded by regularly varying function. In case, it shown that our general results lead optimal-rate control with explicit constants. Our also put perspective Turing's formula...

10.3150/16-bej915 article EN Bernoulli 2018-02-02

Stochastic knapsack problems deal with selecting items potentially random sizes and rewards so as to maximize the total reward while satisfying certain capacity constraints. A novel variant of this problem, where are worthless unless collected in bundles, is introduced here. This setup similar Groupon model, a off minimum number users sign up for it. Since optimal algorithm solve problem not practical, several adaptive greedy approaches reasonable time memory requirements studied detail -...

10.1145/1963405.1963432 article EN 2011-03-28

10.1007/s11222-018-9822-6 article EN Statistics and Computing 2018-07-06

We consider two models of summation independent identically distributed random variables with a parameter. The first is motivated by financial applications and the second contact for species migration. characterize limiting distributions their bifurcations under different relationships between parameter number summands. find that in phase transition we may get are quite from those come up standard limit theorems. Our results suggest these provide better models, at least certain aggregation...

10.1137/s0040585x97t987090 article EN Theory of Probability and Its Applications 2015-01-01

10.1007/s11203-015-9118-9 article EN Statistical Inference for Stochastic Processes 2015-04-01

The flipped classroom pedagogy is a popular framework for teaching computing courses. This hinges on students completing the preparatory (prep) work before class. usually requires watching videos or reading several sections from textbook. To encourage to do prep work, short multiple-choice online quiz often given. However, despite this incentive, many not spend enough time work. deal with challenge, we introduce new approach that designed be more engaging. replaces regular textbook an...

10.1145/3300115.3309520 article EN 2019-05-03

Value-at-Risk (VaR) is one of the best known and most heavily used measures financial risk. In this paper, we introduce a non-iterative semiparametric model for VaR estimation called single index quantile regression time series (SIQRTS) model. To test its performance, give an application to four major US market indices: S&P 500 Index, Russell 2000 Dow Jones Industrial Average, NASDAQ Composite Index. Our results suggest that method has good finite sample performance often outperforms number...

10.1080/02664763.2019.1597028 article EN Journal of Applied Statistics 2019-03-24
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