Marek Flaska

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In many real-world classification problems, the labels of training examples are randomly corrupted. Most previous theoretical work on classification with label noise assumes that the two classes are separable, that the label noise is independent of the true class label, or that the noise proportions for each class are known. In this work, we give conditions(More)
We describe the use of the MCNP-PoliMi code to simulate, on an event-by-event basis, the detection of neutrons by organic scintillators. This code keeps track of single neutron interactions, including the collision nucleus, the energy deposited, and the time distribution of collision events. We show that the total pulse-height response is given by the sum(More)
Fast and accurate identification of neutron sources is very important in nuclear nonproliferation and international safeguards applications. Commonly, the identification of neutron spectra relies on unfolding procedures, which requires the solution of an ill-posed problem. In this paper, we present a new application of an existing technique, which can be(More)
Regulating the proliferation of nuclearmaterials has become an important issue in our society. In order to detect the radiation given off by nuclear materials, systems implementing detectors connected to data processing modules have been developed. We have implemented a scalable, portable detection platform with a data processingmodule about the size of an(More)
A hybrid pulse shape discrimination (PSD) method is presented that combines a charge-integration PSD method with a reference-pulses PSD method. The reference-pulses PSD method uses detailed knowledge of the average, energy-dependent detector response to radiation. To obtain the reference-pulses, a large number of neutron and gamma-ray pulses was averaged in(More)
In this paper, we present a neutron spectrum unfolding technique based on a modification of the least-squares method. The main innovation is the use of a Krylov subspace iteration method to solve the least-squares normal equations. This method was employed because it performs better on ill-conditioned systems of linear equations as compared with standard(More)
We present a correlation-based detection technique that significantly improves the probability of detection for low energy pulses.We propose performing a normalized cross-correlation of the incoming pulse data to a predefined pulse template, and using a threshold correlation value to trigger the detection of a pulse. This technique improves the detector(More)
This work illustrates a methodology based on photon interrogation and coincidence counting for determining the characteristics of fissile material. The feasibility of the proposed methods was demonstrated using the Monte Carlo-based MCNPX/MCNPPoliMi code system capable of simulating the full statistics of the neutron and photon field generated by the photon(More)
Recently, significant research efforts have been focused on utilizing digital techniques for fast pulse detection and pulse shape discrimination (PSD) for gamma/neutron detectors. Figure 1(a) illustrates a typical experimental setup and pulse detection technique that uses a fast digitizer unit to digitize the pulse data coming from a photo-multiplier tube(More)
Article history: Received 8 October 2008 Received in revised form 19 November 2008 Accepted 19 November 2008 Available online 12 January 2009 0306-4549/$ see front matter 2008 Elsevier Ltd. A doi:10.1016/j.anucene.2008.11.023 * Corresponding author. Tel.: +1 734 615 7830; fax E-mail address: clarkesd@umich.edu (S.D. Clarke). Active photon interrogation(More)