Generalised approach to the recognition of structurally similarhandwritten characters using multiple expert classifiers

It is observed that a particular classifier using a particular set of features will generally exhibit a greater probability of confusion among certain character classes than among others. In general these confusion classes are a substantial source of error in the overall performance of the classifier. A productive way to deal with the problem is to separate these characters and reprocess them further in an independent secondary stage in the framework of a multiple expert configuration. The philosophy is to use multiple classifiers to re-evaluate these relatively difficult characters by treating them as special and specific problem cases. In extending special treatment to these characters, advantage can be taken of distinctive structural features to design tailor-made algorithms suited to a particular problem. Since such classifiers are required to deal only with a limited number of classes, very versatile classifiers can be implemented. The main difficulty of this philosophy is to devise a way to group characters together to make sure that these specialised classifiers receive a stream of input characters which indeed belong to the particular group of characters associated with that particular classifier. The authors present a general philosophy for multi-expert classification and deal with the specific problem of formation of distinctive character streams with a high degree of confidence. It then elaborates on other techniques and variations that can be adopted to make this type of multiple expert configuration more effective     

A study of vapour phase epitaxy of indium phosphide

The results of a study of the preparation of epitaxial layers of indium phosphide on indium phosphide substrates by means of the PCl₃-In-InP process are presented. The limitations of the process as discovered in this study are described. It is proposed that the major reaction species is phosphine and the unpredictable break-down of this compound, along with the presence of oxyhalides in the phosphorus trihalides, are the significant causes of the observed variation of the parameters of the epitaxial layers.     

GSSTP: a signalling transport protocol for DVB‐S2 GSE‐only transmission systems

The current signalling framework for Digital Video Broadcasting systems is based on MPEG‐2 encoded Program Specific Information and System Information tables that rely on the transport stream. It is expected that in the near future, this architecture will be replaced by one based on the Generic Stream Encapsulation protocol, paving the way for the convergence of DVB‐S2 broadcast transmission networks and IP infrastructure. This paper presents a new lightweight Generic Stream Signalling Transport Protocol, which can be used to realise a transmission system based only on the Generic Stream Encapsulation and that efficiently supports filtering of Program Specific Information and System Information tables. Copyright © 2012 John Wiley & Sons, Ltd.     

Oxide morphology and adherence on dental alloys designed for porcelain bonding

The morphology and chemical makeup of oxides formed during degassing heat treatments on the surfaces of Ni-Cr and Co-Cr dental alloys designed for porcelain bonding were examined. A technique was developed for stripping intact oxides from these alloys for SEM examination of the oxide surface originally in contact with the metal. Information on the chemical composition of the films was obtained by energy dispersive X-ray spectroscopy. The poorly adherent oxides were found to be wrinkled, but the metal surfaces beneath these films were wrinkled correspondingly. The loss of oxide-metal contact appeared to be limited to the areas of localized void formation, predominantly in the Cr-rich phases. The undersurfaces of the strongly adherent oxides were found to be covered with minute protrusions of oxide. Large pegs of oxide were found to have extended into the NiBe intermetallic phase of these alloys. Beryllium appears to be the oxygen-active element responsible for peg formation.     

X-ray Diffraction Characterization of the Enamel–Steel Interface

In the enameling of steel, the oxide is generally regarded as being completely dissolved by the fusing enamel, with the enamel–metal bond forming directly between oxide-saturated glass and metal. According to this model, the adherence of the oxide layer present on the surface of the steel as the enamel begins to fuse is irrelevant, because none of the original oxide layer remains in the matured enamel–steel bond. This model has not been completely verified, however, and some researchers have presented evidence for the presence of a layer of wüstite (FeO) at the enamel–steel interface on the order of 1 to 4 μm in thickness. Whether such a layer exists has important implications regarding the mechanism of enamel–steel adherence. In the present study, a method was developed to concentrate whatever crystalline material might be present in the interfacial zone to make it more amenable to detection by X-ray diffraction. Through the use of wüstite standards, the present technique was shown to be capable of detecting a layer of wüstite at the enamel–steel interface as thin as 0.3 μm. However, in neither one-coat nor two-coat enameling could a layer of wüstite be demonstrated at the enamel–steel interface. Hence, there does not appear to be a 1-to-4-μm-thick wüstite layer at the enamel–steel interface. If a layer of iron oxide is present at the interface, it must be thinner than 0.3 μm.     

A quantitative method of data evaluation in pattern recognition

The quantitative evaluation of a data set is very useful when approaching problems in pattern recognition. This paper introduces a quality factor measurement which predicts the degree of distinguishability among pairs of pattern classes, and which is shown to be particularly relevant in relation to n-tuple pattern classifiers. Some examples of the use of such a measure in predicting the effectiveness of preprocessing algorithms are considered.     

Enhancing multiple expert decision combination strategies throughexploitation of a priori information sources

The concept of combining multiple experts in a unified framework to generate a combined decision based on individual decisions delivered by the cooperating experts has been exploited in solving the problem of handwritten and machine printed character recognition. The level of performance achieved in terms of the absolute recognition performance and increased confidences associated with these decisions is very encouraging. However, the underlying philosophy behind this success is still not completely understood. The authors analyse the problem of decision combination of multiple experts from a completely different perspective. It is demonstrated that the success or failure of the decision combination strategy largely depends on the extent to which the various possible sources of information are exploited in designing the decision combination framework. Seven different multiple expert decision combination strategies are evaluated in terms of this information management issue. It is demonstrated that it is possible to treat the comparative evaluation of the multiple expert decision combination approaches based on their capability for exploiting diverse information extracted from the various sources as a yardstick in estimating the level of performance that is achievable from these combined configurations     

Signature verification revisited: promoting practical exploitationof biometric technology

Despite research over a long period, biometric approaches to authenticating personal identity have not met with the degree of success in practical applications originally predicted. This paper discusses approaches to biometric testing, focusing particularly on automatic signature verification, and addresses some of the important issues which might help to promote the introduction of practical systems in the future. Examples associated with the adoption of an explicitly flexible approach to signature verification are used to illustrate the discussion, and it is argued that there is still considerable potential for practical exploitation of this type of technology