Search results for "Statistical"
showing 10 items of 4960 documents
Export market integration in the European Union
2004
This paper examines the degree and recent evolution (1988-2001) of export-price dispersion among European Union countries. It also explores the effect of exchange rates on exportprice dispersion by reviewing the experience of some European countries that participated in the exchange rate stability zone. The results indicate that export-price dispersion across European Union countries was usually lower than across OECD countries. Moreover, although there is little evidence of convergence, this is stronger across European Union countries. Finally, even though price dispersion was often lower across European Union countries where exchange rates have been relatively stable than across countries…
Firm Demography in the Accommodation Industry. Evidence from Italian Insular Regions
2020
The purpose of this study is to analyse the spatial pattern and the post-entry performance of tourism businesses in the Italian insular regions of Sardinia and Sicily. Using geo-referenced micro-data for the period 2011-2014, we explore the spatial distribution of ac-commodation firms in the two insular regions, and then compare the coastal and inland areas of the two regions. We observe a higher dispersion of firms in Sardinia than in Sicily; the latter, however having a higher concentration of firms in coastal and urban areas. We do not find significant differences in survival probability across the two insular regions but we do detect significant differences be-tween coastal and inland a…
Zotepin versus Perazin bei Patienten mit paranoider Schizophrenie: eine doppelblind-kontrollierte Wirksamkeitsprüfung
1991
The dibenzothiepine zotepine is a new potential "atypical" neuroleptic exhibiting powerful antiserotonergic and antidopaminergic properties. The efficacy of zotepine was evaluated in a double-blind controlled trial versus the tricyclic neuroleptic perazine in 41 patients suffering mainly from the paranoid-hallucinatory type of schizophrenia. The key outcome variable was the extent of mental disturbance as defined by the total score of the BPRS. Additional outcome variables were GAS and CGI. In addition, adverse reactions and extrapyramidal side effects were assessed according to the FSUCL scale and the Gerlach and AIMS rating scale, respectively. Additional variables recorded were blood pre…
Economic Robustness Analysis of Adaptive Chart Schemes for Monitoring the Total Nonconformities Number in Inspection Units
2015
In recent years, a variety of enhanced schemes for the c chart have been developed aimed at the effectiveness improving of the related statistical process control (SPC) procedures. However, the performance of such chart schemes can be very sensitive to values assumed for some operating and cost parameters, in particular to the considered process shift magnitude arising from out-of-control conditions. In such a circumstance, the effectiveness of such chart schemes can be subjected to substantial reductions when they are implemented in operative contexts given that, in practice, such value is unknown and it can be very difficult to accurately estimate. For this reason, in the present paper i…
A Multi-Objective Design Approach for the c Chart Considering Taguchi Loss Function
2013
The present paper proposes a multi-objective design approach for the c chart, considering in the optimization process of the chart parameters both the statistical and the economic objectives. In particular, the minimization of the hourly total quality related costs is the considered objective to carry out the economic goal, whereas the statistical objective is reached by the minimization the out-of-control average run length of the chart. A mixed integer non-linear constrained mathematical model is formulated to solve the treated multi-objective optimization problem, whereas the Pareto optimal frontier is described by the e-constraint method. In order to show the employment of the proposed …
Comparing the Economic Effectiveness of Various Adaptive Schemes for the c Chart
2013
In an attempt to improve the effectiveness of statistical process control (SPC) procedures, a variety of adaptive schemes has been developed in the last decades. However, considering control charts for attributes, relatively few works about adaptive schemes have been proposed, and most of them were proposed only recently. The common characteristic of those schemes is that one or more chart parameters are allowed to adaptively vary during the SPC operations according to the sampling information history, typically the current point plotted on the chart. In this way, the adaptive schemes are smarter than the related static ones, but they are also more complicated in terms of implementation. Th…
An Effective Double Sampling Scheme for thecControl Chart
2013
In the present paper is developed a statistical process control inspection procedure based on a new simple-to-implement and effective double sampling scheme for the c control chart, aimed at the minimization of the number of inspected observation units and warranting fixed levels for the type I and II error risks. In particular, the formulations of the false alarm risk α, the power P of the chart, and the expected number of inspected observation units for the developed inspection procedure are given, whereas a macro of Microsoft Excel is adopted to solve the tackled problem. In order to illustrate the application of the developed approach and to investigate on the influence of several opera…
Economic Design Approach for an SPC Inspection Procedure Implementing The Adaptive C Chart
2013
The present paper proposes a design approach for a statistical process control (SPC) procedure implementing a c control chart for non-conformities, with the aim to minimize the hourly total quality-related costs. The latter take into account the costs arising from the non-conforming products while the process is in-control and out-of-control, for false alarms, for assignable cause locations and system repairs, for sampling and inspection activities and for the system downtime. The proposed economic optimization approach is constrained by the expected hourly false alarms frequency, as well as the available labor resource level. A mixed integer non-linear constrained mathematical model is dev…
Characterisation and optimal design of a new double sampling <i>c</i> chart
2019
This paper proposes a new double sampling scheme for c control chart (DS-c), which was designed to improve the performance of c chart or to reduce the inspection cost. The mathematical expression required to do an exact evaluation of ARL and ASN is deduced. Further, a bi-objective genetic algorithm is implemented to obtain the optimal design of the DS-c scheme. This optimisation is aimed to simultaneously minimising the error probability type II and the ASN, guaranteeing a desired level for the error probability type I. A performance comparison between the double sampling (DS), fixed parameters (FP), variable simple size (VSS) and exponential weighted moving average (EWMA) schemes for the c…
Prevalence and factors associated with circadian blood pressure patterns in hypertensive patients.
2009
Comment in Timing of antihypertensive therapy and circadian blood pressure pattern. [Hypertension. 2009] Timing of antihypertensive therapy and circadian blood pressure pattern. Almirall J, Martínez-Ocaña JC, Comas L. Hypertension. 2009 Jun; 53(6):e41; author reply e42. Epub 2009 May 4. Dipping comes of age: the importance of nocturnal blood pressure. [Hypertension. 2009]. Dipping comes of age: the importance of nocturnal blood pressure. O'Brien E. Hypertension. 2009 Mar; 53(3):446-7. Epub 2009 Jan 26.Nondipping in patients with hypertension. [Hypertension. 2009] Ambulatory blood pressure (BP) monitoring has become useful in the diagnosis and management of hypertensive individuals. In addit…