Search results for "Statistic"
showing 10 items of 12520 documents
Evaluation of Innovation Statistics Data Quality Dimensions.
2017
Promocijas darbā analizēta praktiskā situācija statistikas par inovācijām vākšanas un apstrādes procesā Latvijā, tiek apskatīta statistikas par inovācijām metodoloģija un tās pielietošanas prakse Latvijā, īpašu uzmanību pievēršot Latvijas inovāciju sistēmas īpatnībām. Pētījumā izstrādātās Latvijas inovāciju vadības un informācijas plūsmas sistēmas ietvaros tiek pamatots informatīvā atbalsta nozīmīgums lēmumu pieņemšanā. Balstoties uz Datu kvalitātes dimensiju novērtēšanas metodiku, veikts inovāciju statistikas datu kvalitātes novērtējums Latvijā. Ir izstrādāta un aprobēta Iteratīvā metode neraksturīgo punktu ietekmes mazināšanai. Pētījuma ietvaros tiek aplūkoti statistikas par inovācijām kv…
Community detection of seismic point processes
2022
In this paper, we combine robin and Local Indicators of Spatio-Temporal Association (LISTA) functions. robin is an R package to assess the robustness of the community structure of a network found by one or more methods to give indications about their reliability. We use it to propose a classification algorithm of events in a spatio-temporal point pattern, by means of the local second-order characteristics and the community detection procedure in network analysis. We demonstrate the proposed procedure on a real data analysis on seismic data.
The Impact of Single-Level ACDF on Neural Foramen and Disc Height of Surgical and Adjacent Cervical Segments: A Case-Series Radiological Analysis
2023
Background: ACDF has become one of the established procedures for the surgical treatment of symptomatic cervical spondylosis, showing excellent clinical results and effective improvements in neural functions and neck pain relief. The main purpose of ACDF is neural decompression, and it is considered by some authors as an indirect result of the intervertebral distraction and cage insertion and the consequent restoration of the disc space and foramen height. Methods: Radiological data from 28 patients who underwent single-level ACDF were retrospectively collected and evaluated. For neural foramen evaluation, antero-posterior (A-P) and cranio-caudal (C-C) diameters were manually calculated; fo…
Population Properties of Compact Objects from the Second LIGO-Virgo Gravitational-Wave Transient Catalog
2021
Abbott, R., et al. (LIGO and Virgo Collaboration)
Noise effect in a sine-Gordon Lattice
2013
International audience; This paper is devoted to the influence of internal noise in a sine-Gordon chain exhibiting the well known nonlinear supratransmission phenomenon. It is shown that spatiotemporal noise can trigger breather modes with a given probability in a range of parameters where they do not occur without noise. A frequency analysis is carried out to quantify the degree of coherence of the emitted breather. It is shown that there exists an appropriate amount of noise which ensures the existence of breather modes with the best coherence.
Quantum Non-Markovian Piecewise Dynamics from Collision Models
2017
Recently, a large class of quantum non-Markovian piecewise dynamics for an open quantum system obeying closed evolution equations has been introduced [B. Vacchini, Phys. Rev. Lett. 117, 230401 (2016)]. These dynamics have been defined in terms of a waiting-time distribution between quantum jumps, along with quantum maps describing the effect of jumps and the system's evolution between them. Here, we present a quantum collision model with memory, whose reduced dynamics in the continuous-time limit reproduces the above class of non-Markovian piecewise dynamics, thus providing an explicit microscopic realization.
A Multi-Objective Design Approach for the c Chart Considering Taguchi Loss Function
2014
The present paper proposes a multi-objective design approach for the c chart, considering in the optimization process of the chart parameters both the statistical and the economic objectives. In particular, the minimization of the hourly total quality related costs is the considered objective to carry out the economic goal, whereas the statistical objective is reached by the minimization the out-of-control average run length of the chart. A mixed integer non-linear constrained mathematical model is formulated to solve the treated multi-objective optimization problem, whereas the Pareto optimal frontier is described by the «-constraint method. In order to show the employment of the proposed …
CALIBRATION OF LÉVY PROCESSES USING OPTIMAL CONTROL OF KOLMOGOROV EQUATIONS WITH PERIODIC BOUNDARY CONDITIONS
2018
We present an optimal control approach to the problem of model calibration for L\'evy processes based on a non parametric estimation procedure. The calibration problem is of considerable interest in mathematical finance and beyond. Calibration of L\'evy processes is particularly challenging as the jump distribution is given by an arbitrary L\'evy measure, which form a infinite dimensional space. In this work, we follow an approach which is related to the maximum likelihood theory of sieves. The sampling of the L\'evy process is modelled as independent observations of the stochastic process at some terminal time $T$. We use a generic spline discretization of the L\'evy jump measure and selec…
Smoothed score confidence interval for the breakpoint in segmented regression
2012
For the breakpoint parameter in segmented regression we consider confidence intervals based on the score statistic. Due to unsmoothness of the score, we propose to build the confidence intervals using its smoothed version under proper shape restrictions. Some simulations are presented to assess the finite sample performance of the proposed approach.
Testing for a breakpoint in segmented regression: a pseudo score approach
2011
To overcome the well known oddities in testing for the existence of a breakpoint in segmented regression models, we discuss a novel approach based on the Pearson X2 statistic which can be understood as an approximation of the Score statistic. We describe the method and present results from some simulations.