The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
One of well-known groups of cluster analysis methods is the group of methods
based on density estimation. In the paper we propose a new method of defining dusters
which consists of two steps. In the first step we find local maxima of the joint distribution
thus establishing clusters centres. In the second step we assign observations to one of existing
clusters centres. The number of clusters is...
This paper is an attempt to compare the performance of an algorithm for
determining the number of clusters in a data set proposed by the author with other methods
of determining the number of clusters. The idea of the new algorithm is based on the
comparison of pseudo cumulative distribution functions of a certain random variable. For
a fixed window size we draw К different points and for every...
Talavera has proposed a method of variable selection in cluster analysis for data
sets in which only variables measured on nominal scale are present. He examined the method on
a couple of data sets basing his assessment on the case in which one can use a data grouping algorithm
(he used the COBWEB algorithm). In other approaches some authors try to select variables
without referring to any particular...
In the paper, a modification o f agglomerative clustering algorithms is
proposed which can be applied to any kind o f agglomeraitve algorithm. The idea o f die
modification is to stress the local density o f observations’ distribution, while performing
clustering based on the dissimilarity matrix. The following clustering algorithms are
examined: single link, complete link, group average link...
The original HINoV method (Carmone et al., 1999 ) is not robust to the presence
of correlated unimodal and uniform variables among noisy variables (e.g. Korzeniewski, 2012).
Moreover, HINoV can be applied only to a single cluster structure analysis. In the article,
a modification is proposed consisting in grouping all variables (separately for each reference
variable) into two classes. One of...
When one groups set elements with the help of k-means it is crucial
to choose starting points properly. If they are chosen incorrectly one may arrive at badly
grouped elements. In the paper a new method of choosing starting points is proposed. It
is based on the distance matrix only. Starting points are chosen so as to improve the
classical method of choosing points which are as far from one another...
Population ageing has drawn increasingly more attention to the question of retirement. On the one hand, the number of retirees increases and retirement becomes a more prominent part of life. As a result, people at present have developed a distinct retirement lifestyle and retirees become more diverse. This study presents how the choices of young retirees (individuals that are retired for no longer...
Poland is one of the most significant examples of a transition country in Central
and Eastern Europe. After 45 years of being a centrally planned economy Poland
emerged at the end of the 1980’s a free-market economy. In 2004 Poland became
a member of the European Union, which was another milestone in the transition
process. Undoubtedly, institutions were a very important factor in Poland’s economic...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.