Efficient disease detection in gastrointestinal videos – global features versus neural networks

Multimedia Tools and Applications - Analysis of medical videos from the human gastrointestinal (GI) tract for detection and localization of abnormalities like lesions and diseases requires both...     

Nonparametric Estimation and Testing in Panels of Intercorrelated Time Series

Abstract.  We consider nonparametric estimation and testing of linearity in a panel of intercorrelated time series. We place the emphasis on the situation where there are many time series in the panel but few observations for each of the series. The intercorrelation is described by a latent process, and a conditioning argument involving this process plays an important role in deriving the asymptotic theory. To be accurate the asymptotic distribution of the test functional of linearity requires a very large number of observations, and bootstrapping gives much better finite sample results. A number of simulation experiments and an illustration on a real data set are included.     

A new preconditioned conjugate gradient power flow

A new solution methodology for the constant matrix, decoupled power flow problem is presented in this paper. The proposed method uses the conjugate gradient method instead of the traditional direct solution of Ax=b for updating the power flow variables. The conjugate gradient method is accelerated with an approximate inverse matrix preconditioner obtained from a linear combination of matrix-valued Chebyshev polynomials. The new method has been tested on several systems of different sizes. In terms of speed, the method is comparable to the fast decoupled load flow in serial environments but it is more amenable to parallel and vector processing since it contains only matrix-vector multiplications.     

An Empirical Research on the Impacts of organisational decisions’ locus,tasks structure rules,knowledge, and IT function’s value on ERP system success

This research examined the impacts of organisational decisions’ locus, tasks structure, rules and procedures, organisational actors’ information technology (IT) skills/knowledge and IT department’s or function’s value perceptions on enterprise resource planning (ERP) system success. While such antecedent factors matter in the discourse, research on their impacts on ERP success is rare. To increase understanding in the area, we proposed a research model and developed pertinent hypotheses that included the above-mentioned factors. Using a cross-sectional field survey, we collected data from 165 firms in three European countries. Data analysis was performed using the partial least squares (PLS) technique. Statistical support was found for 11 out of the 17 hypotheses formulated. Organisational design constructs, i.e. tasks structure, rules and procedures, in-house IT personnel skills/knowledge have impacts on ERP success, whereas the perceptions of IT function’s value and business employees’ IT skills/knowledge did not. Contributions and practical implications of the research are discussed.     

Computational Methods for Inclined Cracks in Orthotropic Functionally Graded Materials Under Thermal Stresses

This article sets forth two different computational methods developed to evaluate fracture parameters for inclined cracks lying in orthotropic functionally graded materials, that are under the effect of thermal stresses. The first method is based on the J _k -integral, whereas the second entails the use of the J ₁-integral and the asymptotic displacement fields. The procedures introduced are implemented by means of the finite element method and integrated into a general purpose finite element analysis software. Numerical results are generated for an inclined edge crack in an orthotropic functionally graded layer subjected to steady-state thermal stresses. Comparisons of the mixed-mode stress intensity factors computed by the use of the proposed methods to those calculated by the displacement correlation technique point out that both approaches lead to numerical results of high accuracy. Further results are provided in order to illustrate the influences of inclination angle, material property gradation, and crack length upon the thermal fracture parameters.     

Natural organic matter (NOM) in a limed lake and its tributaries

The chemistry of a limed lake and its main tributaries were studied for 3 years (1992-94) with an emphasis on natural organic matter (NOM). Increased transparency and decreased water colour indicated a general reduction of NOM in the lake. Increased A(254 nm)/A(410 nm) ratios in the epilimnion during summer and early autumn suggested degradation of higher molecular size organic matter into low molecular size NOM. Increase in ammonium and dissolved inorganic carbon concentrations in the lake was possibly due to the NOM degradation. Using budget calculations and the literature values, photodegradation and microbial activity were estimated to be the main mechanisms of the NOM removal. These mechanisms accounted for about 30-35% and 60-65% of the total loss of organic matter, respectively, in the summer and early autumn period. Low sedimentation rates indicate that co-precipitation of organic matter with calcium, aluminium and/or iron was of minor importance in these seasons.     

Assessing the Changeability of two Object-Oriented Design Alternatives--a Controlled Experiment

An important motivation for the object-oriented paradigm is to improve the changeability of the software, thereby reducing lifetime development costs. This paper describes the results of controlled experiments assessing the changeability of a given responsibility-driven (RD) design versus an alternative control-oriented mainframe (MF) design. According to Coad and Yourdon's OO design quality principles, the RD design represents a good design. The MF design represents a bad design. To investigate which of the designs have better changeability, we conducted two controlled experiments--a pilot experiment and a main experiment. In both experiments, the subjects were divided in two groups in which the individuals designed, coded and tested several identical changes on one of the two design alternatives.The results clearly indicate that the good RD design requires significantly more change effort for the given set of changes than the alternative bad MF design. This difference in change effort is primarily due to the difference in effort required to understand how to solve the change tasks. Consequently, reducing class-level coupling and increasing class cohesion may actually increase the cognitive complexity of a design. With regards to correctness and learning curve, we found no significant differences between the twodesigns. However, we found that structural attributes change less for the RD design than for the MF design. Thus, the RD design may be less prone to structural deterioration. A challenging issue raised in this paper is therefore the tradeoff between change effort and structural stability.     

普适质量评价原则及其模型

在分析质量观演变规律及其价值判断本质的基础上，首先提出了一种新的普适质量观以及与之相适应的评价标准；继之，利用效用函数理论；构建了用于反映普适质量水平的模型；进而，通过对该模型的分析，揭示了检验合格率和顾客满意度指数分别是该模型的两种特例。