Search results for "Weighted"

Exclusive MRI-based tandem and colpostats reconstruction in gynaecological brachytherapy treatment planning

2008

Purpose: According to the GYN GEC-ESTRO Recommendations, MRI is needed with the modality of T2 weighted. CT-MR compatible tandem Plus colpostats (T/C) (Nucletron) is widely used in cervical brachytherapy. The major challenge of MRI is the lack of dummy catheters. Therefore, an additional imaging modality is usually required. One disadvantage of sliced-based reconstruction is that resolution in longitudinal directions can be affected by the slice thickness. The aim of this study is to present a modified T/C applicator in which the catheter visibility is significantly improved. Methods and materials: A modification to the existing T/C applicator has been made available, increasing the cathete…

Aggregation systems for sales forecasting

2015

Abstract Sales forecasting consists of calculating the expected sales of a specific product or company. An important issue when dealing with sales forecasting is the calculation of the average sales, usually using the arithmetic mean or the weighted average. This study introduces new methods for calculating the average sales. These methods are two modern aggregation operators: the ordered weighted average, and the unified aggregation operator. The main advantage of this approach is the possibility to deal with uncertain and complex environments in a more complete way. The study develops some key examples through multi-person and multi-criteria techniques. The study also presents a numerical…

Confidence bands for Horvitz-Thompson estimators using sampled noisy functional data

2013

When collections of functional data are too large to be exhaustively observed, survey sampling techniques provide an effective way to estimate global quantities such as the population mean function. Assuming functional data are collected from a finite population according to a probabilistic sampling scheme, with the measurements being discrete in time and noisy, we propose to first smooth the sampled trajectories with local polynomials and then estimate the mean function with a Horvitz-Thompson estimator. Under mild conditions on the population size, observation times, regularity of the trajectories, sampling scheme, and smoothing bandwidth, we prove a Central Limit theorem in the space of …

Small solid renal masses: Characterization by diffusion-weighted MRI at 3 T

2013

AIM: To describe the appearance of small solid renal lesions (≤3 cm) on diffusion-weighted magnetic resonance imaging (MRI) and to determine whether ADC measurements may help to differentiate benign from malignant small solid renal masses. METHODS AND MATERIALS: Thirty-five patients with 47 small renal masses (23 malignant, 24 benign) who underwent 3 T MRI of the kidney using diffusion-weighted sequences (b values of 0 and 1000 s/mm(2)) were retrospectively evaluated. Qualitative and quantitative analysis of diffusion-weighted images was performed. RESULTS: Most lesions were hyperintense to kidney on high b-value diffusion-weighted images and hypointense on apparent diffusion coefficient (A…

A Similarity Evaluation Technique for Cooperative Problem Solving with a Group of Agents

1999

Evaluation of distance or similarity is very important in cooperative problem solving with a group of agents. Distance between problems is used by agents to recognize nearest solved problems for a new problem, distance between solutions is necessary to compare and evaluate the solutions made by different agents, and distance between agents is useful to evaluate weights of the agents to be able to integrate them by weighted voting. The goal of this paper is to develop a similarity evaluation technique to be used for cooperative problem solving with a group of agents. Virtual training environment used for this goal is represented by predicates that define relationships within three sets: prob…

Marine reserves: size and age do matter

2008

Marine reserves are widely used throughout the world to prevent overfishing and conserve biodiversity, but uncertainties remain about their optimal design. The effects of marine reserves are heterogeneous. Despite theoretical findings, empirical studies have previously found no effect of size on the effectiveness of marine reserves in protecting commercial fish stocks. Using 58 datasets from 19 European marine reserves, we show that reserve size and age do matter: Increasing the size of the no-take zone increases the density of commercial fishes within the reserve compared with outside; whereas the size of the buffer zone has the opposite effect. Moreover, positive effects of marine reserve…

Whole-body diffusion-weighted MR and FDG-PET/CT in Hodgkin Lymphoma: Predictive role before treatment and early assessment after two courses of ABVD

2017

Abstract Purpose To evaluate whether imaging features of pathologic lymph nodes on whole-body diffusion-weighted MR have a predictive role before treatment and may assess the response after two courses of chemotherapy in comparison to FDG-PET/CT in Hodgkin Lymphoma. Materials and methods We reviewed the whole-body MR and FDG-PET/CT performed on 41 patients with Hodgkin Lymphoma before and after two Doxorubicin-Bleomycin-Vinblastine-Dacarbazine (ABVD). Responder and non-responder lesions were identified on interim-FDG-PET/CT performed after two ABVD. We used Multivariate Generalized Estimating Equations model to assess statistical association between being-responder and baseline-Maximum Stan…

L'ESSENZIALE NELL'IMAGING RM DI DIFFUSIONE, COLLO

2011

CURRENT ASSETS STRUCTURE AND EXPLORATION OF BUSINESS IN LATVIA

2012

In order to ensure the financial sustainability of companies under current economic conditions successful management of current assets is crucial. In practice it is quite often observed that the decisions of current assets management in companies are made in the short-term aspects not making analysis. The aim of the article is to explore and analyse the structure of current assets and their indicators in business in Latvia. In order to reach the aim the author solves the following tasks in the research: to explore and analyse the structure of current assets, its changes and trends in the companies of Latvia; to perform calculations and analysis of the indicators characterizing the effective…

Do Country Stereotypes Exist in PISA? A Clustering Approach for Large, Sparse, and Weighted Data

2015

Certain stereotypes can be associated with people from different countries. For example, the Italians are expected to be emotional, the Germans functional, and the Chinese hard-working. In this study, we cluster all 15-year-old students representing the 68 different nations and territories that participated in the latest Programme for International Student Assessment (PISA 2012). The hypothesis is that the students will start to form their own country groups when clustered according to the scale indices that summarize many of the students’ characteristics. In order to meet PISA data analysis requirements, we use a novel combination of our previously published algorithmic components to reali…