Coreference detection of low quality objects

The problem of record linkage is a widely studied problem that aims to identify coreferent (i.e. duplicate) data in a structured data source. As indicated by Winkler, a solution to the record linkage problem is only possible if the error rate is sufficiently low. In other words, in order to succesfully deduplicate a database, the objects in the database must be of sufficient quality. However, this assumption is not always feasible. In this paper, it is investigated how merging of low quality objects into one high quality object can improve the process of record linkage. This general idea is illustrated in the context of strings comparison, where strings of low quality (i.e. with a high typographical error rate) are merged into a string of high quality by using an n-dimensional Levenshtein distance matrix and compute the optimal alignment between the dirty strings. Results are presented and possible refinements are proposed

Evaluation of Nutrient Index Using Organic Carbon, Available P and Available K Concentrations as a Measure of Soil Fertility in Varahi River Basin, India

Varahi River basin is in the midst of Udupi district in the western part of Karnataka state, covering parts of Kundapura and Udupi taluks in Udupi District, Karnataka, India. Spatial distributions for twenty physical and chemical properties were examined in the soil samples of selected agricultural fields in 28 different locations in Varahi River basin. The present study revealed that there is not much variation in soil fertility status of soils developed on various landforms in the area as the soils were having low to medium in organic carbon (0.06 to 1.20 %) and available nitrogen (6.27 to 25.09 Kg/ha) content; low to medium in available P (2.24 to 94.08 Kg/ha) and deficient to doubtful in available K (20.10 - 412.3 Kg/ha) contents. The soils of Varahi River basin were characterized as low-medium-low (LML) category based on the nutrient index calculated w.r.t. available organic carbon, available P and available K. Further, Sodium Absorption Ratio (SAR) and Exchangeable Sodium Percentage (ESP) indicated that the soils were excellent for irrigation

Spatial distribution of macronutrients in soils of Markandeya river basin, Belgaum(d)​, Karnataka(s)​, India

Markandeya River basin stretches geog. from 15° 56' to 16° 08' N latitude and 74° 37' to 74° 58' E longitude, positioned in the midst of Belgaum district in the northern part of Karnataka state. Spatial distributions for twenty different soil quality characteristics were analyzed in the soil samples collected from 30 selected agricultural fields in the study area. Nutrient index reflected the nutrient status of soil and hence it was calcd. by using already detd. chem. parameters like org. C, available N, available phosphorus, and available potash. The present study revealed that there is not much variation in soil fertility status of soils developed on various landforms in the area. The soils had variable org. matter content and decompn. rates accounting to 0.06 to 1.5 % of org. carbon. Further, it is evident that all the soil samples were having low available nitrogen (29.1-​189.5 Kg​/ha) content, 50​% of the samples has low to medium available P (0.96 to 15.1 Kg​/ha) and 90​% of the samples showed adequate supply of available potash (313.3-​1500.8 Kg​/ha)​. Sodium Absorption Ratio (SAR) and Exchangeable Sodium Percentage (ESP) indicated that the soils were excellent for irrigation

Geochemistry of groundwater, Markandeya River Basin, Belgaum district, Karnataka State, India

The Markandeya River Basin stretches geog. from 15°56' to 16°08' N latitude and 74°37' to 74°58' E longitude, positioned in the midst of Belgaum district, in the northern part of Karnataka. The groundwater quality of 54 pre-​monsoon samples in the Markandeya River Basin was evaluated for its suitability for drinking and irrigation purposes by estg. pH, EC, TDS, hardness and alky. besides major cations (Na+, K+, Ca2+, Mg2+) and anions (HCO3 -​, Cl-​, SO4 2-​, PO4 3-​, F-​, NO3 -​)​, boron, SAR, % Na, RSC, RSBC, chlorinity index, SSP, non-​carbonate hardness, Potential Salinity, Permeability Index, Kelley's ratio, Magnesium hazard and Index of Base Exchange. Neg. Index of Base Exchange indicates the chloro-​alk. disequil. in the study area and the majority of water samples fall in the rock dominance field based on Gibbs' ratio. Permeability indexes of classes I and II suggest suitability of groundwater for irrigation. Based on Cl, SO4, HCO3 concns., water samples can be classified as normal chloride (96.3​%) and normal sulfate (94.4​%) and normal bicarbonate (44.4​%) water types

Environmental Tritium (3H) and hydrochemical investigations to evaluate groundwater in Varahi and Markandeya river basins, Karnataka, India

The present study aimed at assessing the activity of natural radionuclides (3H) and hydrochem. parameters (viz., pH, EC, F-​, NO3 -​, Cl-​, Ca2+, Mg2+) in the groundwater used for domestic and irrigation purposes in the Varahi and Markandeya river basins to understand the levels of hydrochem. parameters in terms of the relative age(s) of the groundwater contained within the study area. The recorded environmental 3H content in Varahi and Markandeya river basins varied from 1.95 ± 0.25 T.U. to 11.35 ± 0.44 T.U. and 1.49 ± 0.75 T.U. to 9.17 ± 1.13 T.U. resp. Majority of the samples in Varahi (93.34​%) and Markandeya (93.75​%) river basins being pre-​modern water with modern recharge, significantly influenced by pptn. and river inflowing​/sea water intrusion. The EC-​Tritium and Tritium-​Fluoride plots confirmed the existence of higher total dissolved solids (SEC > 500 μS​/cm) and high fluoride (MAC > 1.5 mg​/L) in groundwater of Markandeya river basin, attributed to relatively longer residence time of groundwater interacting with rock formations and vice versa in case of Varahi river basin. The tritium-​EC and tritium-​chloride plots indicated shallow and deep circulating groundwater types in Markandeya river basin and only shallow circulating groundwater type in Varahi river basin. Increasing Mg relative to Ca with decreasing tritium indicated the influence of incongruent dissoln. of a dolomite phase. The samples with high nitrate (MAC > 45 mg​/L) are waters that are actually mixts. of fresh water (contg. very high nitrate, possibly from agricultural fertilizers) and older unpolluted' waters (contg. low nitrate levels)​, strongly influenced by surface source

Multivariate analysis to evaluate geochemistry of groundwater in Varahi river basin of Udupi in Karnataka (India)

The Varahi Irrigation project dam site is located at approx. 6 km from Siddapura, Kundapura taluk, Udupi district with latitude of 13°39' 15" N and a longitude of 74°57'E. Groundwater quality in the study area was evaluated for its suitability for drinking and irrigation purposes by collecting 36 samples during pre-​monsoon period of the year 2005. The quality assessment was made by estg. physico-​chem. parameters, major cations and anions, besides irrigation quality parameters like SAR,​% Na and RSC. It was also noticed that alk. earth elements exceeded alkalies concn. and weak acids exceeded the strong acid element and HCO3-​was the predominant among anions, while Ca-​Mg dominates cations. Classification of water samples based on SAR and Salinity Hazard revealed that majority of the samples were under excellent (S1, 88.88​%) and excellent (C1, 80.56​%) to good (C2, 8.33​%) categories resp. Gibbs' ratio illustrates that majority of water samples fall in the pptn. dominance field, giving an indication that the aquifer recharging is by means of rain​/river water

Principal component analysis and hydrochemical facies characterization to evaluate groundwater quality in Varahi river basin, Karnataka state, India

The present study envisages the importance of graphical representations like Piper trilinear diagram and Chadha’s plot, respectively to determine variation in hydrochemical facies and understand the evolution of hydrochemical processes in the Varahi river basin. The analytical values obtained from the groundwater samples when plotted on Piper’s and Chadha’s plots revealed that the alkaline earth metals (Ca2+, Mg2+) are significantly dominant over the alkalis (Na+, K+), and the strong acidic anions (Cl−, SO42−) dominant over the weak acidic anions (CO32−, HCO3−). Further, Piper trilinear diagram classified 93.48 % of the samples from the study area under Ca2+–Mg2+–Cl−–SO42− type and only 6.52 % samples under Ca2+–Mg2+–HCO3− type. Interestingly, Chadha’s plot also demonstrated the dominance of reverse ion exchange water having permanent hardness (viz., Ca–Mg–Cl type) in majority of the samples over recharging water with temporary hardness (i.e., Ca–Mg–HCO3 type). Thus, evaluation of hydrochemical facies from both the plots highlighted the contribution from the reverse ion exchange processes in controlling geochemistry of groundwater in the study area. Further, PCA analysis yielded four principal components (PC1, PC2, PC3 and PC4) with higher eigen values of 1.0 or more, accounting for 65.55, 10.17, 6.88 and 6.52 % of the total variance, respectively. Consequently, majority of the physico-chemical parameters (87.5 %) loaded under PC1 and PC2 were having strong positive loading (>0.75) and these are mainly responsible for regulating the hydrochemistry of groundwater in the study area