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Dry and wet spell probability analysis by Markov chain model for Kohima ( Nagaland), India
Full text linkFor the purpose of crop planning and to carryout the agricultural practices it is important to know the sequence of dry and wet periods. The present study was undertaken with the objectives to forecast dry and wet spell analysis using Markov Chain Model for Kohima ( Nagaland).The results indicated that probability of occurrence of dry week is higher from week no. 1 to 16 and also from week numbers. 41 to 52. The range of probability of occurrence of dry week in these weeks varies from 55.56 to 100 per cent. The probability of occurrence of dry week preceded by another dry week is higher in week no.1 to 13,15 , 41, 43-52. The range of probability occurrence of dry week preceded by another dry week in these weeks is ranging from 36.36 to 50 per cent. There is 22.22 to 50 per cent probability that two consecutive dry weeks would occur from week numbers 1 to 13, 15, 41 and 43 to 52. The probability of occurrence of three consecutive dry weeks was found very low varying from 0 to 16.67 per cent in most of the weeks
Frequency analysis for one day to seven consecutive days annual maximum rainfall for Kohima (Nagaland), India: Frequency analysis for one day to seven consecutive days annual maximum rainfall
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ABSTRACT
In this study, daily rainfall data recorded at Kohima (25° 40’N latitude, 94°07’E longitude altitude 1420 m) over a span of 26 years (1997-2022) were gathered. As there's a lack of information on the frequency analysis of annual 1-day to seven consecutive days annual maximum rainfall in Kohima, Nagaland, this study fills that gap.
A turning point test suggested that one to seven consecutive days annual maximum rainfall could be considered random. A Lognormal probability distribution function was found to be the best fit for 1-day annual maximum rainfall data, while a Log-Pearson Type III probability distribution function was found to be the best fit for 3, 4, and 6-days consecutive days annual maximum rainfall data. Extreme value type-I probability distribution function was found to be the best fit for 2, 5, and 7-days consecutive days annual maximum rainfall data.
For a recurrence interval of every two years, an annual maximum rainfall of 72.9 mm in one day, 93.8 mm in two days, 107.18 mm in three days, 119.98 mm in four days, 132.68 mm in five days, 138.58 mm in six days, and 158.98 mm in seven days is expected. For a recurrence interval of 100 years, the expected annual maximum rainfall in one day, two days, three days, four days, five days, six days, and seven days are 144 mm, 188.1 mm, 199.8 mm, 269 mm, 270.2 mm, 332.9 mm, and 324.4 mm, respectively.
Single-parametric models were developed for 1-day as well as 2-7 consecutive day annual maximum rainfall corresponding to 1-100 years return period. The coefficient of determination ranged from 0.964 to 0.997. Relationships were established for 2-7 consecutive maximum rainfall with one-day annual maximum rainfall, with the coefficient of determination varying from 0.994 to 0.997. It's important to note that these relationships are specific to the data used, and their application can significantly simplify the analysis of long-term data for individual stations.
Keywords: Consecutive days annual maximum rainfall, Turning point test, Continuous probability distribution function, Regression model
Determination of surface drainage coefficient - a case study of Doimukh (Arunachal Pradesh), India
Full text linkIn this study, 1 day to 7 consecutive days annual maximum rainfall was predicted at various return periods using probability distribution functions for Doimukh (Arunachal Pradesh), India. Basic infiltration (Ib) rate value was estimated 10 mm hr-1 for the agricultural field having sandy soil. The drainage coefficient was estimated for 5, 10, 20 and 25 years R.I. by subtracting basic infiltration rate from estimated consecutive day rainfall. For the study area, the maximum value of drainage coefficient at 25 years recurrence interval varied from 41.37 mm day-1 to 304.23 mm day-1 for 2 to 7days consecutive rainfall. The minimum value of drainage coefficient at 5 years interval varied from 0 to 212.30 mm day-1 for 2 to7days consecutive rainfall. Study concluded that sandy soil of Doimukh (Arunachal Pradesh) having basic infiltration rate 10 mm hr-1 had to be provided with agricultural drainage for its major crops grown in the area
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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