CHITRA: Cognitive handprinted input-trained recursively analyzing system for recognition of alphanumeric characters

A novel system for recognition of handprinted alphanumeric characters has been developed and tested. The system can be employed for recognition of either the alphabet or the numeral by contextually switching on to the corresponding branch of the recognition algorithm. The two major components of the system are the multistage feature extractor and the decision logic tree-type catagorizer. The importance of ldquogoodrdquo features over sophistication in the classification procedures was recognized, and the feature extractor is designed to extract features based on a variety of topological, morphological and similar properties. An information feedback path is provided between the decision logic and the feature extractor units to facilitate an interleaved or recursive mode of operation. This ensures that only those features essential to the recognition of a particular sample are extracted each time. Test implementation has demonstrated the reliability of the system in recognizing a variety of handprinted alphanumeric characters with close to 100% accuracy.

Artificial database for character recognition research

This paper describes a technique for artificial generation of learning and test sample sets suitable for character recognition research. Sample sets of English (Latin), Malayalam, Kannada and Tamil characters are generated easily through their prototype specifications by the endpoint co-ordinates, nature of segments and connectivity.

Formation of lead pyrophosphate glass and the role of anion disproportionation

Thermal, spectroscopic and electrical properties of lead pyrophosphate glass prepared by melt quenching have been examined. A model based on the structural disproportionation of the P2O 7 4− ions has been proposed and is shown to consistently explain all the observations. The equilibrium of various anionic species has been discussed on the basis of their electronegativities which are in turn related to their basicities.

Ruthenium-Oxygen Coordination-Driven Self-Assembly of a Ru-8(II) Incomplete Prism: Synthesis, Structure, and Shape-Selective Molecular Recognition Study

Coordination-driven self-assembly of 1,3,5-benzenetricarboxylate (tma; 1) and oxalato-bridged p-cymeneruthenium(II) building block Ru-2(mu-eta(4)-C2O4)(MeOH)(2)(eta(6)-p-cymene)(2)](O3SCF3)(2) (2) affords an unusual octanuclear incomplete prism Ru-8(eta(6)-p-cymene)(8)(tma)(2)(mu-eta(4)-C2O4)(2)(OMe)(4)](O3SCF3)( 2) (3), which exhibits a remarkable shape-selective binding affinity for neutral phenolic compounds via hydrogen-bonding interactions (p-cymene = p-(PrC6H4Me)-Pr-i). Such a binding was confirmed by single-crystal X-ray diffraction analysis using 1,3,5-trihydroxybenzene as an analyte.

Character recognition — A review

The machine replication of human reading has been the subject of intensive research for more than three decades. A large number of research papers and reports have already been published on this topic. Many commercial establishments have manufactured recognizers of varying capabilities. Handheld, desk-top, medium-size and large systems costing as high as half a million dollars are available, and are in use for various applications. However, the ultimate goal of developing a reading machine having the same reading capabilities of humans still remains unachieved. So, there still is a great gap between human reading and machine reading capabilities, and a great amount of further effort is required to narrow-down this gap, if not bridge it. This review is organized into six major sections covering a general overview (an introduction), applications of character recognition techniques, methodologies in character recognition, research work in character recognition, some practical OCRs and the conclusions.

Metal-Insulator Transitions in Anion-Excess LaMnO3+? Controlled by the Mn4+ Content

LaMnO3+? samples with Mn4+ content up to 50% have been prepared by different methods. The structure of LaMnO3+? changes from orthorhombic to cubic (via rhombohedral) with increase in the Mn4+ content. LaMnO3+? samples containing greater than 20% Mn4+ are ferromagnetic and show resistivity maxima at a temperature Tt which is close to the ferromagnetic Curie temperature. The resistivity maximum is due to the occurrence of a metal-insulator transition. In samples heated to the same temperature, the value of Tt increases with % Mn4+. For a given sample, Tt increases with the temperature of heat treatment due to the increase in particle size. The onset of ferromagnetism in LaMnO3+? accompanied by an insulator-metal transition is similar to that found in La1-xCaxMnO3 and La1-xSrxCoO3.

Interaction of Sesbania Mosaic Virus Movement Protein with VPg and P10: Implication to Specificity of Genome Recognition

Sesbania mosaic virus (SeMV) is a single strand positive-sense RNA plant virus that belongs to the genus Sobemovirus. The mechanism of cell-to-cell movement in sobemoviruses has not been well studied. With a view to identify the viral encoded ancillary proteins of SeMV that may assist in cell-to-cell movement of the virus, all the proteins encoded by SeMV genome were cloned into yeast Matchmaker system 3 and interaction studies were performed. Two proteins namely, viral protein genome linked (VPg) and a 10-kDa protein (P10) c v gft encoded by OFR 2a, were identified as possible interacting partners in addition to the viral coat protein (CP). Further characterization of these interactions revealed that the movement protein (MP) recognizes cognate RNA through interaction with VPg, which is covalently linked to the 59 end of the RNA. Analysis of the deletion mutants delineated the domains of MP involved in the interaction with VPg and P10. This study implicates for the first time that VPg might play an important role in specific recognition of viral genome by MP in SeMV and shed light on the possible role of P10 in the viral movement.

Recognition of Polycyclic Aromatic Hydrocarbons and Their Derivatives by the 1,3-Dinaphthalimide Conjugate of Calix4]arene: Emission, Absorption, Crystal Structures, and Computational Studies

Polycyclic aromatic hydrocarbons (PAHs) are environmental pollutants as well as well-known carcinogens. Therefore, it is important to develop an effective receptor for the detection and quantification of such molecules in solution. In view of this, a 1,3-dinaphthalimide derivative of calix4]arene (L) has been synthesized and characterized, and the structure has been established by single crystal XRD. In the crystal lattice, intermolecular arm-to-arm pi center dot center dot center dot pi overlap dominates and thus L becomes a promising receptor for providing interactions with the aromatic species in solution, which can be monitored by following the changes that occur in its fluorescence and absorption spectra. On the basis of the solution studies carried out with about 17 derivatives of the aromatic guest molecular systems, it may be concluded that the changes that occur in the fluorescence intensity seem to be proportional to the number of aromatic rings present and thus proportional to the extent of pi center dot center dot center dot pi interaction present between the naphthalimide moieties and the aromatic portion of the guest molecule. Though the nonaromatic portion of the guest species affects the fluorescence quenching, the trend is still based on the number of rings present in these. Four guest aldehydes are bound to L with K-ass of 2000-6000 M-1 and their minimum detection limit is in the range of 8-35 mu M. The crystal structure of a naphthaldehyde complex, L.2b, exhibits intermolecular arm-to-arm as well as arm-to-naphthaldehyde pi center dot center dot center dot pi interactions. Molecular dynamics studies of L carried out in the presence of aromatic aldehydes under vacuum as well as in acetonitrile resulted in exhibiting interactions observed in the solid state and hence the changes observed in the fluorescence and absorption spectra are attributable for such interactions. Complex formation has also been delineated through ESI MS studies. Thus L is a promising receptor that can recognize PAHs by providing spectral changes proportional to the aromatic conjugation of the guest and the extent of aromatic pi center dot center dot center dot pi interactions present between L and the guest.

The Zintl ion As-7](2-): an example of an electron-deficient As-x radical anion

K(2,2,2-crypt)](2)As-7]center dot THF, 1 (2,2,2-crypt = 4,7,13,16,21,24-hexaoxa-1,10-diazabicyclo8.8.8]hexacosane) is the first well characterized seven-atom radical anion of group 15. UV-Vis spectroscopy confirms the presence and electronic structure of As-7](2-). Cyclic voltammetry in DMF solution shows the As-7(3) /As-7(2) redox couple as a one-electron reversible process. Theoretical investigations explore the bonding and properties of compound 1.

ChemInform Abstract: Synthesis of Anion-Deficient Layered Perovskites, ACa2Nb3-xMxO10-x (A: Rb, Cs; M: Al, Fe), Exhibiting Ion-Exchange and Intercalation. Evidence for the Formation of Layered Brownmillerites, ACa2Nb2AlO9 (A: Cs, H)

Anion-deficient layered perovskite oxides of the formula, ACa2Nb3-xMxO10-x (A = Rb, Cs; M = Al, Fe) for 0 < x less-than-or-equal-to 1.0, possessing tetragonal structures similar to the parent ACa2Nb3O10, have been synthesized. The interlayer A cations in these materials are readily exchanged with protons in aqueous HNO3 to give the protonated derivatives, HCa2Nb3-xMxO10-x; the latter are solid Bronsted acids intercalating a number of organic amines including aniline (pK(a) = 4.63). The distribution of acid sites in the interlayer region of HCa2Nb2MO9 inferred from n-alkylamine intercalation suggests that oxygen vacancies and Nb/M atoms are disordered in the ACa2Nb2MO9 samples prepared at 1100-1200-degrees-C. Annealing a disordered sample of CsCa2Nb2AlO9 for a long time at lower temperatures tends to order the Nb/Al atoms and oxygen vacancies to produce octahedral (NbO6/2)-tetrahedral (AlO4/2)-octahedral (NbO6/2) layer sequence reminiscent of the brownmillerite structure.

AM(1-x)Al(x)O(3-x) (A=Na or K; M=Nb or Ta): New anion-deficient Perovskite oxides exhibiting oxide ion conduction

Anion-deficient perovskite oxides of the formula AM(1-x)Al(x)O(3-x) (A = Na or K; M = Nb or Ta) have been prepared for 0 < x less than or equal to 0.5. Diffraction experiments reveal that while the potassium compounds adopt orthorhombic/cubic perovskite structures similar to the parent KNbO3/KTaO3, the sodium compound, NaNb0.5Al0.5O2.5, possesses a brownmillerite/LaSr-CuAlO5-like superstructure. Al-27 NMR spectra show an exclusive tetrahedral oxygen coordination for AI(III) in Na-Nb0.5Al0.5O2.5 (I) and both tetrahedral and octahedral coordination for Al(III) in KNb0.5Al0.5O2.5 (II). The results suggest a long-range and short-range ordering of oxide ion vacancies in I and II respectively. Electrical conductivity measurements show a significant oxide ion conduction for KNb1-xAlxO3-x, with the conductivity increasing with x up to x = 0.5. The differences in the Arrhenius plots of the ionic conductivity of I and II have been rationalized in terms of the long-range and short-range ordering of oxide ion vacancies in the anion-deficient perovskite oxides.

Bile acids in asymmetric synthesis and molecular recognition

This account summarizes the progress made in our laboratory towards the development of new uses of naturally occurring bile acids. Applications in Asymmetric Synthesis (intramolecular coupling, and intermolecular reactions) and Molecular Recognition are described with suitable examples.