نتایج جستجو برای: systematic error random error epid
تعداد نتایج: 790237 فیلتر نتایج به سال:
Larynx may alternatively serve as a target or organs at risk (OAR) in head and neck cancer (HNC) image-guided radiotherapy (IGRT). The objective of this study was to estimate IGRT parameters required for larynx positional error independent of isocentric alignment and suggest population-based compensatory margins. Ten HNC patients receiving radiotherapy (RT) with daily CT on-rails imaging were a...
Introduction: Despite the ongoing efforts to reduce human errors in various systems, errors and unsafe behavior are the main cause of accidents in the workplace. Many studies have been conducted to identify and improve human error in recent years. The number of studies about the human error with the variety of topics has made it an overall overview difficult for researchers. Therefore, a system...
During the evaluation of the continuous measurement signal of analytical instruments by a digital computer, the signal is sampled periodically, and the analytical information [1] is computed from this sequence of discrete values representing the signal by the procedure called data reduction [2]. For example, retention data, peak heights and/or peak areas are produced from the raw discretized si...
Multileaf collimator (MLC) calibration and quality control is a time-consuming procedure typically involving the processing, scanning and analysis of films to measure leaf and collimator positions. Faster and more reliable calibration procedures are required for these tasks, especially with the introduction of intensity modulated radiotherapy which requires more frequent checking and finer posi...
The present study aimed to investigate the accuracy and precision estimation of the number, basal area and volume of the standing trees by methods of random and systematic random sampling in the forests of West Guilan. The cost or inventory time was determined using the criteria (E%2 × T). Inventory was carried out by complete sampling (census) in an area of 52 hectares. The study area (sect...
As an alternative to the oversimplified error schemes currently adopted in establishing quality control (QC) strategies, a complex model was assumed implying (a) the distribution of errors (critical error is regarded as a value discriminating between "effective errors" to be detected and "subcritical errors" which do not interfere with the medical decision whose detection is considered as a fal...
Accurate alignment of linear accelerator table rotational axis with radiation isocenter is critical for noncoplanar radiotherapy applications. The purpose of the present study is to develop a method to align the table rotation axis and the MV isocenter to submillimeter accuracy. We developed a computerized method using electronic portal imaging device (EPID) and measured alignment stability ove...
Error: In everyday language, error is getting things wrong, usually in relation to aims and purposes [67]. There is a different technical use of the term error in statistics [27]. For statisticians, error means differences in repeated measurements. These measurement differences arise from either random variation or bias. Random variation causes inconsistent differences between measurements; bia...
nowadays in trade and economic issues, prediction is proposed as the most important branch of science. existence of effective variables, caused various sectors of the economic and business executives to prefer having mechanisms which can be used in their decisions. in recent years, several advances have led to various challenges in the science of forecasting. economical managers in various fi...
نمودار تعداد نتایج جستجو در هر سال
با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید