Профессору Н. А. Колпаковой - 70 лет

1 сентября 2012 г. исполнилось 70 лет доктору химических наук, ветерану труда, заместителю председателя в специализированном Совете по аналитической химии, члену двух специализированных Советов по физической химии, профессору Томского политехнического университета Нине Александровне Колпаково

Inference in receiver operating characteristic surface analysis via a trinormal model‐based testing approach

Receiver operating characteristic (ROC) analysis is the methodological framework of choice for the assessment of diagnostic markers and classification procedures in general, in both two‐class and multiple‐class classification problems. We focus on the three‐class problem for which inference usually involves formal hypothesis testing using a proxy metric such as the volume under the ROC surface (VUS). In this article, we develop an existing approach from the two‐class ROC framework. We define a hypothesis‐testing procedure that directly compares two ROC surfaces under the assumption of the trinormal model. In the case of the assessment of a single marker, the corresponding ROC surface is compared with the chance plane, that is, to an uninformative marker. A simulation study investigating the proposed tests with existing ones on the basis of the VUS metric follows. Finally, the proposed methodology is applied to a dataset of a panel of pancreatic cancer diagnostic markers. The described testing procedures along with related graphical tools are supported in the corresponding R‐package trinROC, which we have developed for this purpose

Inference in receiver operating characteristic surface analysis via a trinormal model‐based testing approach

Receiver operating characteristic (ROC) analysis is the methodological framework of choice for the assessment of diagnostic markers and classification procedures in general, in both two‐class and multiple‐class classification problems. We focus on the three‐class problem for which inference usually involves formal hypothesis testing using a proxy metric such as the volume under the ROC surface (VUS). In this article, we develop an existing approach from the two‐class ROC framework. We define a hypothesis‐testing procedure that directly compares two ROC surfaces under the assumption of the trinormal model. In the case of the assessment of a single marker, the corresponding ROC surface is compared with the chance plane, that is, to an uninformative marker. A simulation study investigating the proposed tests with existing ones on the basis of the VUS metric follows. Finally, the proposed methodology is applied to a dataset of a panel of pancreatic cancer diagnostic markers. The described testing procedures along with related graphical tools are supported in the corresponding R‐package trinROC, which we have developed for this purpose

Производные и интегралы дробных комплексных порядков функций дискретной переменной

Вводится дискретный d-оператор дробного интегродифференцирования комплексных порядков. Рассматривается алгоритм дискретного дифференцирования и дискретного интегрирования функций дискретной переменной

The behaviour of reinforced concrete beam-column joints under cyclic loading

This project investigates the behaviour of reinforced concrete beam-column joints under the application of high intensity cyclic loading. The experiments, which were carried out on specimens with a beam framing in on only one side of the joint, were conducted to investigate the amount of transverse reinforcement required for confinement and shear resistance in the joint and column regions, in order to establish the ductility available in the column, when subjected to simulated seismic loading. Four units were tested during the experimental program, the design parameters being:- (i) the amount of transverse reinforcement in the joint. (ii) the method of anchoring the beam flexural steel in the joint. (iii) the amount of transverse reinforcement in the column. The type of failure mechanism, and the cause of degradation in stiffness in the post-elastic range, is examined for each specimen leading to a critical appraisal of the joint detail. From the results obtained during testing, recommendations rave been suggested for the design of reinforced concrete joints, including ways in which detailing could be improved to enable the load resisting capacity to be sustained during post-elastic cycles

Confirming the unusual temperature dependence of the electric-field gradient in Zn

The electric-field gradient (EFG) at nuclei in solids is a sensitive probe of the charge distribution. Experimental data, which previously only existed in insulators, have been available for metals with the development of nuclear measuring techniques since about 1970. An early, systematic investigation of the temperature dependence of the EFG in metals, originally based on results for Cd, but then also extended to various other systems, has suggested a proportionality to T 3/2 . However, later measurements in the structurally and electronically similar material Zn, which demonstrated much more complex behavior, were largely ignored at the time. The present experimental effort has confirmed the reliability of this unexpected behavior, which was previously unexplained