Studied are differences of two approaches targeted to reveal latent variables in binary data. These approaches assume that the observed high dimensional data are driven by a small number of hidden binary sources combined due to Boolean superposition. The first approach is the Boolean matrix factorization (BMF) and the second one is the Boolean factor analysis (BFA). The two BMF methods are used for comparison. First is the M8 method from the BMDP statistical software package and the second one is the method suggested by Belohlavek \& Vychodil. These two are compared to BFA, especially with the Expectation-maximization Boolean Factor Analysis we had developed earlier has, however, been extended with a binarization step developed here. The well-known bars problem and the mushroom dataset are used for revealing the methods' peculiarities. In particular, the reconstruction ability of the computed factors and the information gain as the measure of dimension reduction was under scrutiny. It was shown that BFA slightly loses to BMF in performance when noise-free signals are analyzed. Conversely, BMF loses considerably to BFA when input signals are noisy.
Archaeological sources provide a wide range of information to help understand the social structure of human society in the past. In this paper, the authors deal with the information potential of grave pit modifi cations and wooden structures in graves at burial sites in the central region of Great Moravia (southeast Moravia, southwest Slovakia). The goal at this point is to defi ne the basic hypotheses and describe the methodological basis along with the research methodology. The authors treat the sources holistically, which means that one of the methodological foundations is the claim that the properties of the whole are not a simple sum of its parts. This means that all recognized elements of the funeral rite and their mutual relations and functions are the center of attention of this research. The primary basis for the research is the assumption that the presence of various wooden structures or wooden burial receptacles in the graves of the Great Moravian period is a common cultural occurrence. It further tests the hypothesis that there was intent behind choosing of these different wooden structures and grave pit modifi cations and their usage, as well as a potential differentiation based on age or gender in the frequency, quality and selection of these modifi cations/arrangements and structures. The main methodological tools are statistical and GIS analysis and the results are compared with published fi ndings from the wider Central European region., Marian Mazuch, Marek Hladík., and Obsahuje seznam literatury
In the present contribution we applied several statistical methods of time series analysis (Fourier transform, least-squares fitting etc.) to the time series of solar wind velocity data to search for hidden periodicities. The solar wind data wo analysed were obtained on probes at the distance 1 AU from the Sun and stretched over the 17 year interval from 1963 to 1980. Because of investigating
long-period components on time scales of 0.5 to 15 years in variations, we processed daily solar wind velocity values averaged over each Bartels rotation Nos. 1784 - 2006, i.e. 223 data. The analysis showed periods of 14.9-13-7, 7.2-7.1, 3.6-3.I, 2.8-2.6, 2.1- 2.0, 1.7-1.4, 1.3, 1.1, 1.0, 0.8, 0.7 and 0.6-0.5 years. Short preliminary comparison is given with periods found in various solar and geomagnetic indices.
Some previous work on arthropod development is insufficiently detailed or incompletely reported. Much of the published information in this area is of limited use for the general analysis of life cycles. These difficulties arise primarily because many experiments do not control fully for the strain of the material (and even its specific identity) nor for rearing conditions, do not adequately take account of the complexity of life cycles and their stages, or are restricted to only part of the life cycle. For example, 285such factors as variable numbers of instars, sexual differences, abbreviated or hidden stages and dormancies may mean that the "average durations" reported apply to an unknown mixture of developmental types. Nor are experiments always designed or results reported and analysed in a logical and transparent manner. Undefined terms may obscure what actual developmental intervals were measured. Highly derived developmental or demographic measures may obscure core data. Statistical information may be inadequate. Such pitfalls are reviewed here, suggesting ways to ensure that results on the duration of development are both valid for specific studies and more widely useful. General experimental difficulties, recommended background information that should be provided, recommended life-cycle intervals and their terminology, and recommended ways to report numerical and statistical information are briefly summarized in tabular form.
Příspěvek je zaměřen na deskripci a analýzu souboru povelkomoravské a mladohradištní keramiky z lokality Kostice – Zadní hrúd v dolním Podyjí. Metoda zpracování keramického souboru spočívá ve statistické analýze dat. Zpracování rozsáhlého souboru keramiky přispělo k poznání produkce keramiky na jižní Moravě v období po zániku Velké Moravy až do sklonku raného středověku, zároveň se podařilo definovat základní vývojové fáze lokality. and The article provides a description and analysis of an assemblage of post-Great Moravian and Late Hillfort pottery from the Kostice – Zadní hrúd site in the lower Dyje region. The pottery assemblage was processed using the statistical analysis of data. The processing of the large pottery assemblage contributed to an understanding of pottery production in south Moravia in the period following the demise of Great Moravia up to the end of the Early Middle Ages; the basic development phases of the site were also defined.
The residual ambiguity of a laser radar system using pulse trains from a mode locking laser has been investigated by computer simulation. Numerical results are given for pulse groups with Gaussian envelope. A slight modification of this signal shape results in strong reduction of the ambiguity.
The Surface Water Department of the Czech Hydrometeorological Institute in 2006 selected a new period for the evaluation of hydrological characteristics of mean daily discharge series. Initially, two fortyyear long periods were considered: 1961-2000 and 1966-2005 and the period of 1961-2005 was finally accepted. Comparison of the still used 1931-1980 period with the new one was carried out using the data from 50 Czech gauging stations that had continuous data time series. The mean long-term runoff of Czech rivers changed very little from 1931-1980 to 1961-2005. Comparison of the variation coefficients brought similar results. However, among specific M-day discharges the low flow values (e.g. Q355d) showed a significant increase. This might reflect not only natural causes but could suggest anthropogenic factors as well. Trend analyses started with testing mean annual runoff at 65 Czech gauging stations that were not influenced by human activity. 34 stations showed an increasing trend and 31 a decreasing trend. However, the trend was statistically significant only at one station. Trends of individual months dramatically differentiate. In January through March the increasing trends prevail. March trends show the highest number of stations with a significant increase. The three following months are complete opposites in which decreasing trends dominate. In May and June, not a single increase was recorded and many decreases were statistically significant. Almost no significant trends were examined in the months of the second half of the year. and V posledních měsících se oddělení povrchových vod ČHMÚ zabývalo výběrem období pro výpočet nových hydrologických charakteristik M-denních průtoků na českých tocích. Uvažována byla čtyřicetiletí 1961-2000 a 1966-2005, nakonec však bylo přijato období 1961-2005. Na datech z 50 vodoměrných stanic, které měly nepřerušené řady pozorování, bylo uskutečněno první srovnání statistických charakteristik období 1931-1980 (doposud používané) a 1961-2005. U nového období byly u neovlivněných stanic vyhodnoceny trendy průměrných ročních průtoků a průtoků jednotlivých měsíců.