In recent years, with the fast development of computer and Internet technologies, text-mining computer methods are becoming more and more important. Computer systems capacities can be further used in ...such areas as text summarization, information retrieval, text correcting, determining text subject, machine text translation, creating lexicons, determining text sentiment. This monograph is focused on sentiment analysis in the most popular meaning of this phrase i.e. on the sentiment of the whole document. The problems of binary classification (two document groups), staying away from external sources, using the training set but in the possibly smallest size, were emphasized. The monograph’s targets are: providing a comparative review of sentiment analysis methods to be found in literature, investigating the quality of selected methods of document sentiment classification in applications to Polish language written documents, proposing new methods which would upgrade the classification quality or possess other advantages. An original method with simple interpretation has been proposed which proved to be better than standard methods applied to classify English language documents, especially in the case of documents corpora with similar number of documents in both classes. The research was carried out on thirteen sets of documents from different independent sources.
The book handed over to the Readers includes the scientific, didactic and organizational achievements of statisticians and demographers of the University of Lodz. It can be treated as a continuation ...of the monograph entitled "Lodz academic statistics", published in 2020. The aim of the book is to present the achievements of statisticians and demographers of the University of Lodz, including precursors who have made a significant contribution to the development of statistics and demography as scientific disciplines and their wide application in many fields of knowledge. The occasion to publish this book was the 77th anniversary of the first lectures conducted by academic teachers at the University of Lodz and at the Lodz Branch of the Warsaw School of Economics. The presented scientific work covers a period of over one hundred years and has contributed to the significant development of statistics and demography in numerous higher education institutions, mainly at the University of Lodz. The Lodz community also supported other universities in Poland by promoting doctors and habilitated doctors, managing scientific projects and by organizing international conferences, including Multivariate Statistical Analysis conference, which will have its 40th edition in 2022. The book is scientific and popular science. It enriches the information on the scientific and didactic achievements of statisticians and demographers of the University of Lodz against the background of Polish, and partly also global, statistics and demography, in the process of historical development. Based on source documents, these achievements were presented against the background of Polish statistical and demographic thought ant its contribution to international statistical congresses.
This book analyzes the Central Asian economies of Kazakhstan, the Kyrgyz Republic, Tajikistan, Turkmenistan, and Uzbekistan, from their buffeting by the commodity boom of the early 2000s to its ...collapse in 2014. Richard Pomfret examines the countries' relations with external powers and the possibilities for development offered by infrastructure projects as well as rail links between China and Europe.
The transition of these nations from centrally planned to market-based economic systems was essentially complete by the early 2000s, when the region experienced a massive increase in world prices for energy and mineral exports. This raised incomes in the main oil and gas exporters, Kazakhstan and Turkmenistan; brought more benefits to the most populous country, Uzbekistan; and left the poorest countries, the Kyrgyz Republic and Tajikistan, dependent on remittances from migrant workers in oil-rich Russia and Kazakhstan. Pomfret considers the enhanced role of the Central Asian nations in the global economy and their varied ties to China, the European Union, Russia, and the United States. With improved infrastructure and connectivity between China and Europe (reflected in regular rail freight services since 2011 and China's announcement of its Belt and Road Initiative in 2013), relaxation of United Nations sanctions against Iran in 2016, and the change in Uzbekistan's presidency in late 2016, a window of opportunity appears to have opened for Central Asian countries to achieve more sustainable economic futures.
Rotation schemes and Chebyshev polynomials Wesołowski, Jacek
Statistics in transition : journal of the Polish Statistical Association,
2023, Letnik:
24, Številka:
3
Journal Article
Recenzirano
Odprti dostop
here is a continuing interplay between mathematics and survey methodology involving different branches of mathematics, not only probability. This interplay is quite obvious as regards the first of ...the two options: probability vs. non-probability sampling, as proposed and discussed in Kalton (2023). There, mathematics is represented by probability and mathematical statistics. However, sometimes connections between mathematics and survey methodology are less obvious, yet still crucial and intriguing. In this paper we refer to such an unexpected relation, namely between rotation sampling and Chebyshev polynomials. This connection, introduced in Kowalski and Wesołowski (2015), proved fundamental for the derivation of an explicit form of the recursion for the BLUE ˆ μt of the mean on each occasion t in repeated surveys based on a cascade rotation scheme. This general result was obtained under two basic assumptions: ASSUMPTION I and ASSUMPTION II, expressed in terms of the Chebyshev polynomials. Moreover, in that paper, it was conjectured that these two assumptions are always satisfied, so the derived form of recursion is universally valid. In this paper, we partially confirm this conjecture by showing that ASSUMPTION I is satisfied for rotation patterns with a single gap of an arbitrary size.
In this excellent overview of the history of probability and nonprobability sampling from the end of the nineteenth century to the present day, Professor Graham Kalton outlines the essence of past ...endeavors that helped to define philosophical approaches and stimulate the development of survey sampling methodologies. From the beginning, there was an understanding that a sample should, in some ways, resemble the population under study. In Kiær’s ideas of “representative sampling” and Neyman’s invention of probability-based approach, the prime concern of survey sampling has been to properly plan for representing characteristics of the finite population. Poststratification and other calibration methods were developed for the same important goal of better representation.
I would like to congratulate Professor Graham Kalton for his significant and inspiring article entitled as "Probability vs. Nonprobability Sampling: From the Birth of Survey Sampling to the Present ...Day". The article provides an elegant overview of the history of survey sampling, covering the purposive approaches that dominated the sampling field in the early days but from the 1940s, at least in official statistics, were gradually replaced entirely by probability-based approaches. Today we may be facing a paradigm shift again, but the direction is the opposite. Non-probability-based approaches are becoming viable, if not the only option, in fields that are moving towards big data and other new data sources and new methodological approaches.
Nicolaie et al. (2010) have advanced a vertical model as the latest continuous time competing risks model. The main objective of this article is to re-cast this model as a nonparametric model for ...analysis of discrete time competing risks data. Davis and Lawrance (1989) have advanced a cause-specific-hazard driven method for summarizing discrete time data nonparametrically. The secondary objective of this article is to compare the proposed model to this model. We pay particular attention to the estimates for the cause-specific-hazards and the cumulative incidence functions as well as their respective standard errors.
I like to congratulate Professor Kalton for writing this very constructive article on probability versus nonprobability sampling. I learned a lot from reading it. In what follows, I add a few ...comments on this topic.
Rejoinder Kalton, Graham
Statistics in transition : journal of the Polish Statistical Association,
2023, Letnik:
24, Številka:
3
Journal Article
Recenzirano
Odprti dostop
I thank the discussants for their kind remarks, for their insightful comments on the present state and future directions of the field, and for the many references they cite. Having no disagreements ...with them, I will confine my rejoinder to a few issues that their contributions have highlighted for me.
Let me first thank Dr. Kalton for his amazing historical review of the development of survey sampling from its origin, contrasting purposive sampling, until now, where some elements of purposive ...sampling in terms of web or big data seem to supersede the well-elaborated theory of survey statistics. Shall the message be that we do not need any sampling courses at universities anymore, that official statistics should turn to modelling using data with unknown data generating processes, or actually even be substituted by (commercial) data krakens? Hardly so! Graham Kalton emphasises a modern thinking about the use of these new data sources which may also have some advantages and he urges future research on data integration methods using (very) different kinds of data while strongly taking quality aspects into account.
