Reliability Analysis of a System with Multiple-Stage Policy Considering Type I and II Errors

2019 ◽  
Vol 26 (06) ◽  
pp. 1950028
Author(s):  
Mitsuhiro Imaizumi ◽  
Mitsutaka Kimura
Keyword(s):  
Type I Error ◽  
The Other ◽  
Renewal Processes ◽  
Type I ◽  
Numerical Examples ◽  
Markov Renewal Processes ◽  
The Mean ◽  
Mean Time ◽  
Server System ◽  
Multiple Stages

This paper formulates a stochastic model for a system with illegal access. The server has the function of IDS, and illegal access is checked in multiple stages which consist of simple check and detailed check. In this model, we consider type I and II errors of simple check and a type I error of detailed check. There are two cases where IDS judges the occurrence of illegal access erroneously. One is when illegal access does not occur, and the other is when illegal access occurs. We apply the theory of Markov renewal processes to a system with illegal access, and derive the mean time and the expected checking number until a server system becomes faulty. Further, an optimal policy which minimizes the expected cost is discussed. Finally, numerical examples are given.

Multiple-Stage Policies for a Server System with Illegal Access

2018 ◽  
Vol 25 (04) ◽  
pp. 1850016 ◽  
Author(s):  
Mitsuhiro Imaizumi ◽  
Mitsutaka Kimura
Keyword(s):  
Stochastic Models ◽  
Internet Technology ◽  
The Internet ◽  
Renewal Processes ◽  
Markov Renewal Processes ◽  
Optimal Policies ◽  
The Mean ◽  
Mean Time ◽  
Server System ◽  
Multiple Stages

As the Internet technology has developed, the demands for the improvement of the reliability and security of the system connected with the Internet have increased. Although various services are performed on the Internet, illegal access on the Internet has become a problem in recent years. This paper formulates stochastic models for a system with illegal access. The server has the function of IDS, and illegal access is checked in multiple stages which consist of simple check, detailed check and dynamic check. We apply the theory of Markov renewal processes to a system with illegal access, and derive the mean time and the expected checking number until a server system becomes faulty. Further, optimal policies which minimize the expected cost are discussed. Finally, numerical examples are given.

Comparison of Means: An F Test Followed by a Modified Multiple Range Procedure

1979 ◽  
Vol 4 (1) ◽  
pp. 14-23 ◽  
Author(s):  
Juliet Popper Shaffer
Keyword(s):  
Error Control ◽  
Type I Error ◽  
Critical Value ◽  
The Other ◽  
Type I ◽  
F Test ◽  
Range Test

If used only when a preliminary F test yields significance, the usual multiple range procedures can be modified to increase the probability of detecting differences without changing the control of Type I error. The modification consists of a reduction in the critical value when comparing the largest and smallest means. Equivalence of modified and unmodified procedures in error control is demonstrated. The modified procedure is also compared with the alternative of using the unmodified range test without a preliminary F test, and it is shown that each has advantages over the other under some circumstances.

Psychophysical interactions with a double-slit interference pattern: Exploratory evidence of a causal influence

2021 ◽  
Vol 34 (1) ◽  
pp. 79-88
Author(s):  
Dean Radin ◽  
Helané Wahbeh ◽  
Leena Michel ◽  
Arnaud Delorme
Keyword(s):  
Experimental Data ◽  
Interference Pattern ◽  
Type I Error ◽  
Human Mind ◽  
The Other ◽  
Type I ◽  
Fringe Visibility ◽  
Future Studies ◽  
Before And After ◽  
Double Slit

An experiment we conducted from 2012 to 2013, which had not been previously reported, was designed to explore possible psychophysical effects resulting from the interaction of a human mind with a quantum system. Participants focused their attention toward or away from the slits in a double-slit optical system to see if the interference pattern would be affected. Data were collected from 25 people in individual half-hour sessions; each person repeated the test ten times for a total of 250 planned sessions. “Sham” sessions designed to mimic the experimental sessions without observers present were run immediately before and after as controls. Based on the planned analysis, no evidence for a psychophysical effect was found. Because this experiment differed in two essential ways from similar, previously reported double-slit experiments, two exploratory analyses were developed, one based on a simple spectral analysis of the interference pattern and the other based on fringe visibility. For the experimental data, the outcome supported a pattern of results predicted by a causal psychophysical effect, with the spectral metric resulting in a 3.4 sigma effect (p = 0.0003), and the fringe visibility metric resulting in 7 of 22 fringes tested above 2.3 sigma after adjustment for type I error inflation, with one of those fringes at 4.3 sigma above chance (p = 0.00001). The same analyses applied to the sham data showed uniformly null outcomes. Other analyses exploring the potential that these results were due to mundane artifacts, such as fluctuations in temperature or vibration, showed no evidence of such influences. Future studies using the same protocols and analytical methods will be required to determine if these exploratory results are idiosyncratic or reflect a genuine psychophysical influence.

scholarly journals Effect of gingival retraction cord and retraction paste on gingival tissue in fixed prosthodontics impression

2014 ◽  
Vol 3 (2) ◽  
pp. 20-27
Author(s):  
Mohammad Shamsuzzaman ◽  
Sheikh Md Shahriar Quader ◽  
Shakila Fatema ◽  
Md Abdul Gofur ◽  
Khaleda Akter
Keyword(s):  
The Other ◽  
Gingival Tissue ◽  
Hemorrhage Control ◽  
Fixed Prosthodontics ◽  
Abutment Teeth ◽  
The Mean ◽  
Mean Time ◽  
Reduced Time

Background & Objectives: Of the various gingival retraction systems available in the market, a cordless paste system is fairly new entrant into this field. This system promises to provide an easier method to obtain optimum retraction with excellent hemorrhage control. The present study was designed to clinically evaluate the efficacy of paste retraction system and medicated retraction cords on the basis of relative easy of working, hemorrhage control and amount of vertical gingival retraction. Methods: 40 subjects were selected requiring full veneer restoration where more than one abutment teeth were to be prepared. After the preparation of the abutment teeth flexible scales were used to measure the sulcus depth before retraction and after retraction. Medicated retraction cord technique was used on one abutment tooth and on the other abutment tooth paste retraction system was employed. Subjectively easy of placement and hemorrhage scores was assessed. Results: The mean time taken for paste retraction technique was 45.13 seconds and for medicated retraction cord technique was 105.4 seconds. In all the subjects paste retraction technique was relatively easier as compared with medicated retraction cord technique. Mean hemorrhage scores using paste retraction technique was 0.05 and using medicated retraction cord technique it was 1.70. Mean vertical gingival retraction using paste retraction technique was .36mm and using medicated retraction cord technique was 0.54mm Conclusion: Within the limitations of this study, paste retraction system requires reduced time for application, is easier to place, and provides excellent hemorrhage control in comparison to medicated retraction cord. However, medicated retraction cord provides increased amount of vertical retraction as compared to paste retraction technique. DOI: http://dx.doi.org/10.3329/updcj.v3i2.17995 Update Dent. Coll. j: 2013; 3 (2): 20-27

scholarly journals Another Warning about Median Reaction Time --- Version of 11 Feb 2020

2020 ◽  
Author(s):  
Jeff Miller
Keyword(s):  
Type I Error ◽  
Reaction Times ◽  
Error Rates ◽  
Type I ◽  
Experimental Conditions ◽  
Type I Error Rates ◽  
Correction Technique ◽  
Inflated Type ◽  
The Mean ◽  
Rt Distributions

Contrary to the warning of Miller (1988), Rousselet and Wilcox (2020) argued that it is better to summarize each participant’s single-trial reaction times (RTs) in a given condition with the median than with the mean when comparing the central tendencies of RT distributions across experimental conditions. They acknowledged that median RTs can produce inflated Type I error rates when conditions differ in the number of trials tested, consistent with Miller’s warning, but they showed that the bias responsible for this error rate inflation could be eliminated with a bootstrap bias correction technique. The present simulations extend their analysis by examining the power of bias-corrected medians to detect true experimental effects and by comparing this power with the power of analyses using means and regular medians. Unfortunately, although bias-corrected medians solve the problem of inflated Type I error rates, their power is lower than that of means or regular medians in many realistic situations. In addition, even when conditions do not differ in the number of trials tested, the power of tests (e.g., t-tests) is generally lower using medians rather than means as the summary measures. Thus, the present simulations demonstrate that summary means will often provide the most powerful test for differences between conditions, and they show what aspects of the RT distributions determine the size of the power advantage for means.

Eating and ruminating behaviour in cattle given forages differing in fibre content

1989 ◽  
Vol 48 (3) ◽  
pp. 503-511 ◽  
Author(s):  
M. N. McLeod ◽  
B. R. Smith
Keyword(s):  
Dry Matter ◽  
The Other ◽  
Fibre Content ◽  
Eating Rate ◽  
High Fibre ◽  
Acid Detergent Fibre ◽  
The Mean ◽  
Voluntary Intake ◽  
Mean Time ◽  
Forage Diets

ABSTRACTA study was made of the effect of fibre level in forages on eating and rumination behaviour. Eight forage diets were prepared from the leaf and stem fractions of two grasses and two legumes and were given at hourly intervals to four steers under steady-state conditions. Eating and rumination behaviour were measured automatically by recording changes in intra-oesophageal pressure.Mean voluntary intake of leaf was higher than that of the stem fractions (9·9 v. 5·6 kg/day; P < 0·001). This was associated with a shorter mean retention time in the rumen of the leaf than that of the stem fractions (21·4 v. 30·6 h; P < 0·001) and a lower concentration (g/100 g dry matter (DM)) of fibre (52-0 neutral-detergent fibre (NDF) and 30·5 acid-detergent fibre (ADF) v. 68·2 NDF and 45·3 ADF). Similar values (P > 0·05) between diets were found for both the water and DM contents of the rumen (60·1 kg, 7·8 kg). Voluntary intake was not related to either.No difference was found between forage diets in the mean time (132 min) and number (18·7) of periods spent eating each day (P > 0·05). Legume leaf fractions were eaten at a faster rate (g/min) than either the grass leaf or the stem fractions. Voluntary intake was related to the rate at which food was eaten (r = 0·89; P < 0·01) but no relationship was found with the time taken to eat food (r = –0·14; P>0·05). Eating rate was related to the level of both NDF (r = –0·91; P < 0·01) and ADF (r = –0·96; P < 0·001).Differences between diets were found in rumination times (mean 425 min; P < 001), the number of boluses regurgitated during each period (27·6; P < 0·05) and during each day (485; P < 0·001), and in the weight of boluses (455 g; P < 0·05). No differences (P > 0·05) were found between diets in the mean number of rumination periods each day (17·6), the mean time spent ruminating during each period (24·3 min), the mean rate at which boluses were regurgitated (53·2 s per bolus), the interval between boluses (5·1 s), and the DM in a bolus (27·5 g). Rumination time and the number of boluses regurgitated either per period or per day were not related to the fibre content of the diet (P > 0·05).The regurgitated boluses from leaf fractions were chewed less than the stem fractions (43·7 v. 54·7 chews per bolus). The regurgitated boluses of lucerne leaf were chewed at a faster rate (1·13 chews per s; P > 0·05) than regurgitated digesta of the other diets which were chewed at similar rates (0·97 chews per s; P > 0·05). The total number of rumination chews made each day by animals given lucerne leaf (12 300) was much lower (P < 0·001) than that by animals given the other fractions (25 300). The number of chews made on each bolus was related to fibre levels in the diets (NDF, r = 0·78, P < 0·05; ADF, r = 0·91, P < 0·01).It is concluded that the voluntary intake of high-fibre diets is not always restricted by rumen fill or rumination. The ease with which forage is eaten should be investigated as a factor influencing intake of fibrous forages.

Seroconversion of puppies to canine parvovirus and canine distemper virus: a comparison of two combination vaccines

2000 ◽  
Vol 36 (2) ◽  
pp. 137-142 ◽  
Author(s):  
MJ Coyne
Keyword(s):  
Canine Distemper Virus ◽  
Serum Antibody ◽  
Canine Parvovirus ◽  
The Other ◽  
Canine Distemper ◽  
Combination Vaccines ◽  
Antibody Titers ◽  
The Mean ◽  
To Receive ◽  
Mean Time

Sixty puppies were randomly assigned to receive one of two commercially available combination vaccines, and responses to the canine parvovirus and canine distemper virus components of the vaccines were determined by measuring serum antibody titers. The percentage of puppies that seroconverted to canine parvovirus was significantly higher and the mean time for seroconversion was significantly shorter for puppies that received one of the vaccines than for puppies that received the other vaccine. Percentages of puppies that seroconverted to canine distemper virus were not significantly different.

AN IMPERFECT PROCESS POLICY WITH PRODUCTION CORRECTION AND REORGANIZATION

2007 ◽  
Vol 14 (02) ◽  
pp. 157-168
Author(s):  
GWO-LIANG LIAO
Keyword(s):  
Operating System ◽  
The Other ◽  
Type I ◽  
Type Ii ◽  
Production Mechanism ◽  
Imperfect Production ◽  
Production Processes ◽  
The Mean ◽  
Control State ◽  
Renewal Cycle

This study applies imperfect production processes to obtain in-control state by production correction and reorganization. Production processes are classified into two types of state: one is the type I state (out-of-control state) and the other is the type II state (in-control state). The type I state involves adjustment of the production mechanism. Production correction is either imperfect; worsening a production system, or perfect, returning it to "in-control" conditions. After N type I states, the operating system must be reorganized and returned to the beginning condition. At the beginning of the production of the each renewal cycle, the state of the process is not always to be restored to "in-control". The mean loss cost until "in-control" state, is determined. The existence of a unique and finite optimal N for an imperfect process under certain reasonable conditions is shown. A numerical example is presented.

Variance heterogeneity, transformations, and models of species abundance: a cautionary tale

2004 ◽  
Vol 61 (7) ◽  
pp. 1294-1302 ◽  
Author(s):  
Brian H McArdle ◽  
Marti J Anderson
Keyword(s):  
Type I Error ◽  
Species Abundance ◽  
Ecological Systems ◽  
Type I ◽  
Data Set ◽  
Bootstrap Tests ◽  
Inflated Type ◽  
The Mean ◽  
Nonparametric Alternatives ◽  
Mean Variance

Ecological systems have intrinsic heterogeneity. Counts of abundances of species often show heterogeneity of variances among observational groups or populations. This is most often dealt with by using a transformation of the data followed by a traditional statistical analysis that requires homogeneity. Such an approach is extremely useful when the mean–variance relationship is consistent across the data set. In some situations, however, the mean–variance relationship does not stay constant, e.g., the degree of spatial aggregation of organisms can change in space and time. In these cases, transforming the data to "fix" the problem of heterogeneity can result in apparently grossly inflated type I error. The use of a transformation alters the model under test and also has an important effect on the spatial scale of the hypothesis. The use of nonparametric alternatives, such as permutation or bootstrap tests, does not solve this problem. Explicit models of these kinds of distributional changes, where they occur, are necessary.

Type I Error Rates and Power Estimates of Selected Parametric and Nonparametric Tests of Scale

1987 ◽  
Vol 12 (1) ◽  
pp. 45-61 ◽  
Author(s):  
Stephen F. Olejnik ◽  
James Algina
Keyword(s):  
Type I Error ◽  
Nonparametric Tests ◽  
Error Rates ◽  
Type I ◽  
Normal Distributions ◽  
Type I Error Rates ◽  
Heavy Tailed Distributions ◽  
The Mean ◽  
Heavy Tailed ◽  
Distribution Type

Estimated Type I error rates and power are reported for the Brown-Forsythe, O’Brien, Klotz, and Siegel-Tukey procedures. The effect of aligning the data, by using deviations from group means or group medians, is investigated for the latter two tests. Normal and non-normal distributions, equal and unequal sample-size combinations, and equal and unequal means are investigated for a two-group design. No test is robust and most powerful for all distributions, however, using O’Brien’s procedure will avoid the possibility of a liberal test and provide power almost as large as what would be provided by choosing the most powerful test for each distribution type. Using the Brown-Forsythe procedure with heavy-tailed distributions and O’Brien’s procedure for other distributions will increase power modestly and maintain robustness. Using the mean-aligned Klotz test or the unaligned Klotz test with appropriate distributions can increase power, but only at the risk of increased Type I error rates if the tests are not accurately matched to the distribution type.

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