AIM: Aegle marmelos is a medicinal herb belonging to the Rutacae family. The fruit of A. marmelos... more AIM: Aegle marmelos is a medicinal herb belonging to the Rutacae family. The fruit of A. marmelos at each stage of ripening is used as ethnomedicine to cure various diseases. The aim of the present study was to determine the components contributing to the medicinal value of the A. marmelos fruit at different stages of ripening. METHODS: High-performance liquid chromatography (HPLC) was used to determine polyphenol, vitamins, organic acids and sugars in A. marmelos fruit at different stages of ripening. RESULTS: Tannin, a polyphenol responsible for astringent and antimicrobial properties of A. marmelos fruit was found to increase during ripening. Riboflavin, a vital medicinal component was detected in traceable amount only in full-ripe A. marmelos fruit. Riboflavin contributes towards body growth, reproduction and red cell production. The content of ascorbic acid (vitamin C) which is useful in preventing scurvy decreased significantly as fruit ripens. CONCLUSIONS: The difference in the medicinal effect of A. marmelos fruit at each stage of ripening might be due to the presence of different amount of polyphenol, vitamins and organic acids.
Pressure-induced structural changes on nano-crystalline La0.8Sr0.2Mn0.8Fe0.2O3 were studied using... more Pressure-induced structural changes on nano-crystalline La0.8Sr0.2Mn0.8Fe0.2O3 were studied using high-pressure Mössbauer spectroscopy and high-pressure X-ray diffraction. Mössbauer measurements up to 10 GPa showed first order transition at 0.52 GPa indicating transformation of Fe4 + to high spin Fe3 + , followed by another subtle transition at 3.7 GPa due to the convergence of two different configurations of Fe into one. High-pressure X-ray diffraction measurements carried up to 4.3 GPa showed similar results at 0.6 GPa as well as 3.6 GPa. Attempts were made to explain the changes at 0.6 GPa by reorientation of grain/grain boundaries due to uniaxial stress generated on the application of pressure. Similarly variation at 3.6 GPa can be explained by orthorhombic to monoclinic transition.
The swift heavy ion irradiated La0.9Mn0.8Fe0.2O3 (La-deficient) system with 200 Mev Ag16 + ion b... more The swift heavy ion irradiated La0.9Mn0.8Fe0.2O3 (La-deficient) system with 200 Mev Ag16 + ion beam at fluence 5 × 1012 ions/cm2 was studied with X-ray diffraction (XRD) and Mössbauer spectroscopic measurements. Comparison of Mössbauer parameters with those of unirradiated sample showed an increase in line width on irradiation which may be due to reduction in particle size as well as due to creation of defects. An increase in quadrupole splitting with no appreciable change in isomer shift showed ion-induced structural disorder in the material after irradiation. An attempt is made to compare the effect of fluence with the hydrostatic pressure on the sample.
The swift heavy ion irradiated La0.9Mn0.8Fe0.2O3 (La-deficient) system with 200 Mev Ag16 + ion b... more The swift heavy ion irradiated La0.9Mn0.8Fe0.2O3 (La-deficient) system with 200 Mev Ag16 + ion beam at fluence 5 × 1012 ions/cm2 was studied with X-ray diffraction (XRD) and Mössbauer spectroscopic measurements. Comparison of Mössbauer parameters with those of unirradiated sample showed an increase in line width on irradiation which may be due to reduction in particle size as well as due to creation of defects. An increase in quadrupole splitting with no appreciable change in isomer shift showed ion-induced structural disorder in the material after irradiation. An attempt is made to compare the effect of fluence with the hydrostatic pressure on the sample.
Pressure-induced structural changes on nano-crystalline La0.8Sr0.2Mn0.8Fe0.2O3 were studied using... more Pressure-induced structural changes on nano-crystalline La0.8Sr0.2Mn0.8Fe0.2O3 were studied using high-pressure Mössbauer spectroscopy and high-pressure X-ray diffraction. Mössbauer measurements up to 10 GPa showed first order transition at 0.52 GPa indicating transformation of Fe4 + to high spin Fe3 + , followed by another subtle transition at 3.7 GPa due to the convergence of two different configurations of Fe into one. High-pressure X-ray diffraction measurements carried up to 4.3 GPa showed similar results at 0.6 GPa as well as 3.6 GPa. Attempts were made to explain the changes at 0.6 GPa by reorientation of grain/grain boundaries due to uniaxial stress generated on the application of pressure. Similarly variation at 3.6 GPa can be explained by orthorhombic to monoclinic transition.
Pressure-induced structural changes on nano-crystalline La0.8Sr0.2Mn0.8Fe0.2O3 were studied using... more Pressure-induced structural changes on nano-crystalline La0.8Sr0.2Mn0.8Fe0.2O3 were studied using high-pressure Mössbauer spectroscopy and high-pressure X-ray diffraction. Mössbauer measurements up to 10 GPa showed first order transition at 0.52 GPa indicating transformation of Fe4 + to high spin Fe3 + , followed by another subtle transition at 3.7 GPa due to the convergence of two different configurations of Fe into one. High-pressure X-ray diffraction measurements carried up to 4.3 GPa showed similar results at 0.6 GPa as well as 3.6 GPa. Attempts were made to explain the changes at 0.6 GPa by reorientation of grain/grain boundaries due to uniaxial stress generated on the application of pressure. Similarly variation at 3.6 GPa can be explained by orthorhombic to monoclinic transition.
The Indus script is one of the major undeciphered scripts of the ancient world. The small size of... more The Indus script is one of the major undeciphered scripts of the ancient world. The small size of the corpus, the absence of bilingual texts, and the lack of definite knowledge of the underlying language has frustrated efforts at decipherment since the discovery of the remains of the Indus civilisation. Recently, some researchers have questioned the premise that the Indus script encodes spoken language. Building on previous statistical approaches, we apply the tools of statistical language processing, specifically $n$-gram Markov chains, to analyse the Indus script for syntax. Our main results are that the script has well-defined signs which begin and end texts, that there is directionality and strong correlations in the sign order, and that there are groups of signs which appear to have identical syntactic function. All these require no {\it a priori} suppositions regarding the syntactic or semantic content of the signs, but follow directly from the statistical analysis. Using information theoretic measures, we find the information in the script to be intermediate between that of a completely random and a completely fixed ordering of signs. Our study reveals that the Indus script is a structured sign system showing features of a formal language, but, at present, cannot conclusively establish that it encodes {\it natural} language. Our $n$-gram Markov model is useful for predicting signs which are missing or illegible in a corpus of Indus texts. This work forms the basis for the development of a stochastic grammar which can be used to explore the syntax of the Indus script in greater detail.
We attempt to create a comprehensive model for the origin and growth of astronomy in a culture. W... more We attempt to create a comprehensive model for the origin and growth of astronomy in a culture. We show that it primarily follows four distinct phases that we classify as the initial, settlement, civilization and technology-based phases. Using examples from Indian prehistory and history we show that these phases mark distinct steps in the growth of astronomy in a culture. While the examples are taken from Indian culture, we suggest that it also should be possible to identify these phases in other cultures.
Archaeological excavations in the sites of the Indus Valley civilization (2500( -1900 in Pakistan... more Archaeological excavations in the sites of the Indus Valley civilization (2500( -1900 in Pakistan and northwestern India have unearthed a large number of artifacts with inscriptions made up of hundreds of distinct signs. To date, there is no generally accepted decipherment of these sign sequences, and there have been suggestions that the signs could be non-linguistic. Here we apply complex network analysis techniques on the database of available Indus inscriptions, with the aim of detecting patterns indicative of syntactic structure in this sign system. Our results show the presence of regularities, e.g., in the segmentation trees of the sequences, that suggest the existence of a grammar underlying the construction of the sequences.
The Indus script is one of the major undeciphered scripts of the ancient world. The small size of... more The Indus script is one of the major undeciphered scripts of the ancient world. The small size of the corpus, the absence of bilingual texts, and the lack of definite knowledge of the underlying language has frustrated efforts at decipherment since the discovery of the remains of the Indus civilisation. Recently, some researchers have questioned the premise that the Indus script encodes spoken language. Building on previous statistical approaches, we apply the tools of statistical language processing, specifically $n$-gram Markov chains, to analyse the Indus script for syntax. Our main results are that the script has well-defined signs which begin and end texts, that there is directionality and strong correlations in the sign order, and that there are groups of signs which appear to have identical syntactic function. All these require no {\it a priori} suppositions regarding the syntactic or semantic content of the signs, but follow directly from the statistical analysis. Using information theoretic measures, we find the information in the script to be intermediate between that of a completely random and a completely fixed ordering of signs. Our study reveals that the Indus script is a structured sign system showing features of a formal language, but, at present, cannot conclusively establish that it encodes {\it natural} language. Our $n$-gram Markov model is useful for predicting signs which are missing or illegible in a corpus of Indus texts. This work forms the basis for the development of a stochastic grammar which can be used to explore the syntax of the Indus script in greater detail.
X-ray reflectivity measurements were performed on several thin foil gold mirrors fabricated in TI... more X-ray reflectivity measurements were performed on several thin foil gold mirrors fabricated in TIFR for a Soft X-ray Imaging Telescope. The mirrors were made from thin aluminum foils with a reflecting layer of sputtered gold transferred from a smooth glass mandrel using an epoxy. X-ray reflectivity measurements were performed on a sample of randomly selected mirrors using CuK α (8.05 keV), CrK α (5.41 keV) X-rays and also at several energies in the energy range of 155–300 eV using the synchrotron source Indus-1. It was found that the roughness of the low-density top gold layer as obtained from the fitting of X-ray reflectivity data for CuK α radiation is relatively more as compared to that obtained from the CrK α radiation. This indicates that in the mirrors made by this process, the upper surfaces are smoother as compared to the deeper layers. It was also observed that the critical angle almost vanishes in the very low energy range of 290–300 eV due to strong absorption effects of the low density material sitting on top of these mirrors. Due to this absorption effect, efficiency of these mirrors reduces in this energy range. This is first time that reflectivity measurements are being reported for very soft X-rays (≤ 300 eV) for mirrors made for any X-ray astronomy mission.
Page 1. 1 ORIGIN AND GROWTH OF ASTRONOMY IN INDIAN CONTEXT MN Vahia1, 2,*, Nisha Yadav1, and Srik... more Page 1. 1 ORIGIN AND GROWTH OF ASTRONOMY IN INDIAN CONTEXT MN Vahia1, 2,*, Nisha Yadav1, and Srikumar Menon3 1 Tata Institute of Fundamental Research, Mumbai 2 Manipal Advanced Research Group, Manipal 3 Manipal Institute of Technology, Manipal ...
Proceedings of The National Academy of Sciences, 2009
Although no historical information exists about the Indus civilization (flourished ca. 2600 -1900... more Although no historical information exists about the Indus civilization (flourished ca. 2600 -1900 B.C.), archaeologists have uncovered about 3,800 short samples of a script that was used throughout the civilization. The script remains undeciphered, despite a large number of attempts and claimed decipherments over the past 80 years. Here, we propose the use of probabilistic models to analyze the structure of the Indus script. The goal is to reveal, through probabilistic analysis, syntactic patterns that could point the way to eventual decipherment. We illustrate the approach using a simple Markov chain model to capture sequential dependencies between signs in the Indus script. The trained model allows new sample texts to be generated, revealing recurring patterns of signs that could potentially form functional subunits of a possible underlying language. The model also provides a quantitative way of testing whether a particular string belongs to the putative language as captured by the Markov model. Application of this test to Indus seals found in Mesopotamia and other sites in West Asia reveals that the script may have been used to express different content in these regions. Finally, we show how missing, ambiguous, or unreadable signs on damaged objects can be filled in with most likely predictions from the model. Taken together, our results indicate that the Indus script exhibits rich synactic structure and the ability to represent diverse content. both of which are suggestive of a linguistic writing system rather than a nonlinguistic symbol system. ancient scripts ͉ archaeology ͉ linguistics ͉ machine learning ͉ statistical analysis
We adopt a comprehensive approach to segment the Indus texts using statistically significant sign... more We adopt a comprehensive approach to segment the Indus texts using statistically significant signs and their combinations in addition to all the texts of length 2, 3 and 4 signs. We find that we can segment 88% of Indus texts (of length 5 and above) by this method and hence it can be suggested that the texts of 5 or more signs can actually be seen as permutations of other frequent sign-combinations or smaller texts (of length 2, 3 or 4 signs). The results of the segmentation process are in agreement with our earlier results (Yadav et. al, 2008, henceforth referred to as Paper 1) where we show the importance of 2, 3 and 4 sign combinations as important units of information. We do not assume anything regarding the content of the script and the work is purely based on the structural analysis of Indus Texts.
The Indus script is one of the major undeciphered scripts of the ancient world. The small size of... more The Indus script is one of the major undeciphered scripts of the ancient world. The small size of the corpus, the absence of bilingual texts, and the lack of definite knowledge of the underlying language has frustrated efforts at decipherment since the discovery of the remains of the Indus civilization. Building on previous statistical approaches, we apply the tools of statistical language processing, specifically n-gram Markov chains, to analyze the syntax of the Indus script. We find that unigrams follow a Zipf-Mandelbrot distribution. Text beginner and ender distributions are unequal, providing internal evidence for syntax. We see clear evidence of strong bigram correlations and extract significant pairs and triplets using a log-likelihood measure of association. Highly frequent pairs and triplets are not always highly significant. The model performance is evaluated using information-theoretic measures and cross-validation. The model can restore doubtfully read texts with an accuracy of about 75%. We find that a quadrigram Markov chain saturates information theoretic measures against a held-out corpus. Our work forms the basis for the development of a stochastic grammar which may be used to explore the syntax of the Indus script in greater detail.
AIM: Aegle marmelos is a medicinal herb belonging to the Rutacae family. The fruit of A. marmelos... more AIM: Aegle marmelos is a medicinal herb belonging to the Rutacae family. The fruit of A. marmelos at each stage of ripening is used as ethnomedicine to cure various diseases. The aim of the present study was to determine the components contributing to the medicinal value of the A. marmelos fruit at different stages of ripening. METHODS: High-performance liquid chromatography (HPLC) was used to determine polyphenol, vitamins, organic acids and sugars in A. marmelos fruit at different stages of ripening. RESULTS: Tannin, a polyphenol responsible for astringent and antimicrobial properties of A. marmelos fruit was found to increase during ripening. Riboflavin, a vital medicinal component was detected in traceable amount only in full-ripe A. marmelos fruit. Riboflavin contributes towards body growth, reproduction and red cell production. The content of ascorbic acid (vitamin C) which is useful in preventing scurvy decreased significantly as fruit ripens. CONCLUSIONS: The difference in the medicinal effect of A. marmelos fruit at each stage of ripening might be due to the presence of different amount of polyphenol, vitamins and organic acids.
Pressure-induced structural changes on nano-crystalline La0.8Sr0.2Mn0.8Fe0.2O3 were studied using... more Pressure-induced structural changes on nano-crystalline La0.8Sr0.2Mn0.8Fe0.2O3 were studied using high-pressure Mössbauer spectroscopy and high-pressure X-ray diffraction. Mössbauer measurements up to 10 GPa showed first order transition at 0.52 GPa indicating transformation of Fe4 + to high spin Fe3 + , followed by another subtle transition at 3.7 GPa due to the convergence of two different configurations of Fe into one. High-pressure X-ray diffraction measurements carried up to 4.3 GPa showed similar results at 0.6 GPa as well as 3.6 GPa. Attempts were made to explain the changes at 0.6 GPa by reorientation of grain/grain boundaries due to uniaxial stress generated on the application of pressure. Similarly variation at 3.6 GPa can be explained by orthorhombic to monoclinic transition.
The swift heavy ion irradiated La0.9Mn0.8Fe0.2O3 (La-deficient) system with 200 Mev Ag16 + ion b... more The swift heavy ion irradiated La0.9Mn0.8Fe0.2O3 (La-deficient) system with 200 Mev Ag16 + ion beam at fluence 5 × 1012 ions/cm2 was studied with X-ray diffraction (XRD) and Mössbauer spectroscopic measurements. Comparison of Mössbauer parameters with those of unirradiated sample showed an increase in line width on irradiation which may be due to reduction in particle size as well as due to creation of defects. An increase in quadrupole splitting with no appreciable change in isomer shift showed ion-induced structural disorder in the material after irradiation. An attempt is made to compare the effect of fluence with the hydrostatic pressure on the sample.
The swift heavy ion irradiated La0.9Mn0.8Fe0.2O3 (La-deficient) system with 200 Mev Ag16 + ion b... more The swift heavy ion irradiated La0.9Mn0.8Fe0.2O3 (La-deficient) system with 200 Mev Ag16 + ion beam at fluence 5 × 1012 ions/cm2 was studied with X-ray diffraction (XRD) and Mössbauer spectroscopic measurements. Comparison of Mössbauer parameters with those of unirradiated sample showed an increase in line width on irradiation which may be due to reduction in particle size as well as due to creation of defects. An increase in quadrupole splitting with no appreciable change in isomer shift showed ion-induced structural disorder in the material after irradiation. An attempt is made to compare the effect of fluence with the hydrostatic pressure on the sample.
Pressure-induced structural changes on nano-crystalline La0.8Sr0.2Mn0.8Fe0.2O3 were studied using... more Pressure-induced structural changes on nano-crystalline La0.8Sr0.2Mn0.8Fe0.2O3 were studied using high-pressure Mössbauer spectroscopy and high-pressure X-ray diffraction. Mössbauer measurements up to 10 GPa showed first order transition at 0.52 GPa indicating transformation of Fe4 + to high spin Fe3 + , followed by another subtle transition at 3.7 GPa due to the convergence of two different configurations of Fe into one. High-pressure X-ray diffraction measurements carried up to 4.3 GPa showed similar results at 0.6 GPa as well as 3.6 GPa. Attempts were made to explain the changes at 0.6 GPa by reorientation of grain/grain boundaries due to uniaxial stress generated on the application of pressure. Similarly variation at 3.6 GPa can be explained by orthorhombic to monoclinic transition.
Pressure-induced structural changes on nano-crystalline La0.8Sr0.2Mn0.8Fe0.2O3 were studied using... more Pressure-induced structural changes on nano-crystalline La0.8Sr0.2Mn0.8Fe0.2O3 were studied using high-pressure Mössbauer spectroscopy and high-pressure X-ray diffraction. Mössbauer measurements up to 10 GPa showed first order transition at 0.52 GPa indicating transformation of Fe4 + to high spin Fe3 + , followed by another subtle transition at 3.7 GPa due to the convergence of two different configurations of Fe into one. High-pressure X-ray diffraction measurements carried up to 4.3 GPa showed similar results at 0.6 GPa as well as 3.6 GPa. Attempts were made to explain the changes at 0.6 GPa by reorientation of grain/grain boundaries due to uniaxial stress generated on the application of pressure. Similarly variation at 3.6 GPa can be explained by orthorhombic to monoclinic transition.
The Indus script is one of the major undeciphered scripts of the ancient world. The small size of... more The Indus script is one of the major undeciphered scripts of the ancient world. The small size of the corpus, the absence of bilingual texts, and the lack of definite knowledge of the underlying language has frustrated efforts at decipherment since the discovery of the remains of the Indus civilisation. Recently, some researchers have questioned the premise that the Indus script encodes spoken language. Building on previous statistical approaches, we apply the tools of statistical language processing, specifically $n$-gram Markov chains, to analyse the Indus script for syntax. Our main results are that the script has well-defined signs which begin and end texts, that there is directionality and strong correlations in the sign order, and that there are groups of signs which appear to have identical syntactic function. All these require no {\it a priori} suppositions regarding the syntactic or semantic content of the signs, but follow directly from the statistical analysis. Using information theoretic measures, we find the information in the script to be intermediate between that of a completely random and a completely fixed ordering of signs. Our study reveals that the Indus script is a structured sign system showing features of a formal language, but, at present, cannot conclusively establish that it encodes {\it natural} language. Our $n$-gram Markov model is useful for predicting signs which are missing or illegible in a corpus of Indus texts. This work forms the basis for the development of a stochastic grammar which can be used to explore the syntax of the Indus script in greater detail.
We attempt to create a comprehensive model for the origin and growth of astronomy in a culture. W... more We attempt to create a comprehensive model for the origin and growth of astronomy in a culture. We show that it primarily follows four distinct phases that we classify as the initial, settlement, civilization and technology-based phases. Using examples from Indian prehistory and history we show that these phases mark distinct steps in the growth of astronomy in a culture. While the examples are taken from Indian culture, we suggest that it also should be possible to identify these phases in other cultures.
Archaeological excavations in the sites of the Indus Valley civilization (2500( -1900 in Pakistan... more Archaeological excavations in the sites of the Indus Valley civilization (2500( -1900 in Pakistan and northwestern India have unearthed a large number of artifacts with inscriptions made up of hundreds of distinct signs. To date, there is no generally accepted decipherment of these sign sequences, and there have been suggestions that the signs could be non-linguistic. Here we apply complex network analysis techniques on the database of available Indus inscriptions, with the aim of detecting patterns indicative of syntactic structure in this sign system. Our results show the presence of regularities, e.g., in the segmentation trees of the sequences, that suggest the existence of a grammar underlying the construction of the sequences.
The Indus script is one of the major undeciphered scripts of the ancient world. The small size of... more The Indus script is one of the major undeciphered scripts of the ancient world. The small size of the corpus, the absence of bilingual texts, and the lack of definite knowledge of the underlying language has frustrated efforts at decipherment since the discovery of the remains of the Indus civilisation. Recently, some researchers have questioned the premise that the Indus script encodes spoken language. Building on previous statistical approaches, we apply the tools of statistical language processing, specifically $n$-gram Markov chains, to analyse the Indus script for syntax. Our main results are that the script has well-defined signs which begin and end texts, that there is directionality and strong correlations in the sign order, and that there are groups of signs which appear to have identical syntactic function. All these require no {\it a priori} suppositions regarding the syntactic or semantic content of the signs, but follow directly from the statistical analysis. Using information theoretic measures, we find the information in the script to be intermediate between that of a completely random and a completely fixed ordering of signs. Our study reveals that the Indus script is a structured sign system showing features of a formal language, but, at present, cannot conclusively establish that it encodes {\it natural} language. Our $n$-gram Markov model is useful for predicting signs which are missing or illegible in a corpus of Indus texts. This work forms the basis for the development of a stochastic grammar which can be used to explore the syntax of the Indus script in greater detail.
X-ray reflectivity measurements were performed on several thin foil gold mirrors fabricated in TI... more X-ray reflectivity measurements were performed on several thin foil gold mirrors fabricated in TIFR for a Soft X-ray Imaging Telescope. The mirrors were made from thin aluminum foils with a reflecting layer of sputtered gold transferred from a smooth glass mandrel using an epoxy. X-ray reflectivity measurements were performed on a sample of randomly selected mirrors using CuK α (8.05 keV), CrK α (5.41 keV) X-rays and also at several energies in the energy range of 155–300 eV using the synchrotron source Indus-1. It was found that the roughness of the low-density top gold layer as obtained from the fitting of X-ray reflectivity data for CuK α radiation is relatively more as compared to that obtained from the CrK α radiation. This indicates that in the mirrors made by this process, the upper surfaces are smoother as compared to the deeper layers. It was also observed that the critical angle almost vanishes in the very low energy range of 290–300 eV due to strong absorption effects of the low density material sitting on top of these mirrors. Due to this absorption effect, efficiency of these mirrors reduces in this energy range. This is first time that reflectivity measurements are being reported for very soft X-rays (≤ 300 eV) for mirrors made for any X-ray astronomy mission.
Page 1. 1 ORIGIN AND GROWTH OF ASTRONOMY IN INDIAN CONTEXT MN Vahia1, 2,*, Nisha Yadav1, and Srik... more Page 1. 1 ORIGIN AND GROWTH OF ASTRONOMY IN INDIAN CONTEXT MN Vahia1, 2,*, Nisha Yadav1, and Srikumar Menon3 1 Tata Institute of Fundamental Research, Mumbai 2 Manipal Advanced Research Group, Manipal 3 Manipal Institute of Technology, Manipal ...
Proceedings of The National Academy of Sciences, 2009
Although no historical information exists about the Indus civilization (flourished ca. 2600 -1900... more Although no historical information exists about the Indus civilization (flourished ca. 2600 -1900 B.C.), archaeologists have uncovered about 3,800 short samples of a script that was used throughout the civilization. The script remains undeciphered, despite a large number of attempts and claimed decipherments over the past 80 years. Here, we propose the use of probabilistic models to analyze the structure of the Indus script. The goal is to reveal, through probabilistic analysis, syntactic patterns that could point the way to eventual decipherment. We illustrate the approach using a simple Markov chain model to capture sequential dependencies between signs in the Indus script. The trained model allows new sample texts to be generated, revealing recurring patterns of signs that could potentially form functional subunits of a possible underlying language. The model also provides a quantitative way of testing whether a particular string belongs to the putative language as captured by the Markov model. Application of this test to Indus seals found in Mesopotamia and other sites in West Asia reveals that the script may have been used to express different content in these regions. Finally, we show how missing, ambiguous, or unreadable signs on damaged objects can be filled in with most likely predictions from the model. Taken together, our results indicate that the Indus script exhibits rich synactic structure and the ability to represent diverse content. both of which are suggestive of a linguistic writing system rather than a nonlinguistic symbol system. ancient scripts ͉ archaeology ͉ linguistics ͉ machine learning ͉ statistical analysis
We adopt a comprehensive approach to segment the Indus texts using statistically significant sign... more We adopt a comprehensive approach to segment the Indus texts using statistically significant signs and their combinations in addition to all the texts of length 2, 3 and 4 signs. We find that we can segment 88% of Indus texts (of length 5 and above) by this method and hence it can be suggested that the texts of 5 or more signs can actually be seen as permutations of other frequent sign-combinations or smaller texts (of length 2, 3 or 4 signs). The results of the segmentation process are in agreement with our earlier results (Yadav et. al, 2008, henceforth referred to as Paper 1) where we show the importance of 2, 3 and 4 sign combinations as important units of information. We do not assume anything regarding the content of the script and the work is purely based on the structural analysis of Indus Texts.
The Indus script is one of the major undeciphered scripts of the ancient world. The small size of... more The Indus script is one of the major undeciphered scripts of the ancient world. The small size of the corpus, the absence of bilingual texts, and the lack of definite knowledge of the underlying language has frustrated efforts at decipherment since the discovery of the remains of the Indus civilization. Building on previous statistical approaches, we apply the tools of statistical language processing, specifically n-gram Markov chains, to analyze the syntax of the Indus script. We find that unigrams follow a Zipf-Mandelbrot distribution. Text beginner and ender distributions are unequal, providing internal evidence for syntax. We see clear evidence of strong bigram correlations and extract significant pairs and triplets using a log-likelihood measure of association. Highly frequent pairs and triplets are not always highly significant. The model performance is evaluated using information-theoretic measures and cross-validation. The model can restore doubtfully read texts with an accuracy of about 75%. We find that a quadrigram Markov chain saturates information theoretic measures against a held-out corpus. Our work forms the basis for the development of a stochastic grammar which may be used to explore the syntax of the Indus script in greater detail.
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Papers by nisha yadav