• Journal of the Korean Statistical Society
• /
• v.36 no.4
• /
• pp.557-578
• /
• 2007

In Response Surface Methodology (RSM), rotatability is a natural and highly desirable property. For second order general correlated regression model, the concept of robust rotatability was introduced by Das (1997). In this paper a new measure of robust rotatability for second order response surface designs with correlated errors is developed and illustrated with an example. A comparison is made between the newly developed measure with the previously suggested measure by Das (1999).

• Journal of the Korean Statistical Society
• /
• v.32 no.4
• /
• pp.337-357
• /
• 2003

This paper introduces new measures for the stability of slope estimation on the second order response surface at a point and on a sphere. As a measure of point stability of slope estimation, we suggest a point dispersion measure of slope variances over all directions at a point. A spherical dispersion measure is also proposed as a measure of spherical stability of slope estimation on each sphere. Some designs are studied to explore the usefulness of the proposed measures. Using the point dispersion measure, another concept of slope rotatability called equally-stable slope rotatability is proposed as a useful property of response surface designs. We provide a set of conditions for a design to have equally-stable slope rotatability.

• Communications for Statistical Applications and Methods
• /
• v.30 no.1
• /
• pp.49-63
• /
• 2023

A lot of studies on the summary measures of predictive strength of categorical response models consider the likelihood ratio index (LRI), also known as the McFadden-R², a better option than many other measures. We propose a simple modification of the LRI that adjusts for the effect of the number of response categories on the measure and that also rescales its values, mimicking an underlying latent measure. The modified measure is applicable to both binary and ordinal response models fitted by maximum likelihood. Results from simulation studies and a real data example on the olfactory perception of boar taint show that the proposed measure outperforms most of the widely used goodness-of-fit measures for binary and ordinal models. The proposed R² interestingly proves quite invariant to an increasing number of response categories of an ordinal model.

• Communications for Statistical Applications and Methods
• /
• v.11 no.3
• /
• pp.563-574
• /
• 2004

Slope rotatability of response surface designs is a desirable property when we are interested in estimating slopes of response surfaces. In this paper, we derive a simplified measure of slope rotatability from new viewpoints for response surface designs that are frequently used in response surface methodology.

• Journal of Korean Society for Quality Management
• /
• v.27 no.1
• /
• pp.59-79
• /
• 1999

The fitting of a response surface model and the subsequent exploration of the response surface are usually based on the assumption that the experimental runs are carried out under homogeneous conditions. This, however, may be quite often difficult to achieve in many experiments. To control such an extraneous source of variation, the response surface design should be arranged in several blocks within which homogeneity of conditions can be maintained. In this case, when fitting a response surface model, the least squares estimates of the model's parameters and the prediction variance will generally depend on how the response surface design is blocked. That is, the choice of a blocking arrangement for a response surface design can have a considerable effect on estimating the mean response and on the size of the prediction variance. In this paper, we propose a measure for evaluating the effect of blocking of response surface designs using cuboidal regions.

• Communications for Statistical Applications and Methods
• /
• v.7 no.2
• /
• pp.415-426
• /
• 2000

Hader and Park (1978) introduced the idea of slope rotatability, and Park (1987) introduced the concept of slope rotatability over all directions, and gave necessary and sufficient conditions. Park and Kim (1992) proposed a measure that represent the extent of slope rotatability for a given response surface design. Kim (1993) proposed a measure that represent the extent of slope rotatavility over all directions. In this paper, we embodied the measure of slope rotatability over all directions. Examples of applying this measure to some response surface designs are also given. In this response surface design of slope rotatavility over all directions, we obtain the mean slope variances on the spherical surface to select better experimental design varying the number of center points and radius.

• International Journal of Human Ecology
• /
• v.5 no.2
• /
• pp.13-29
• /
• 2004

Ryff's(1989) psychological well-being measure is used to assess and sometimes compare Korean and American adults, however, there is no information regarding whether its dimensions are psychometrically invariant across, whether its items provide sufficient information for, and whether each item measures identical trait levels in, the two nations. Confirmatory factor analysis on response 1,696 Korean and 3,669 American adults, gave to the measure revealed lack of fit and absence of factorial invariance across the two nations. Item response theory revealed significant variance for items on each factor across two countries that most items yielded limited psychometric information. And that each item measure different trait levels, suggesting that in its present form, the measure might lead to misleading results for, and across the two nations.

• Journal of Korean Institute of Industrial Engineers
• /
• v.8 no.1
• /
• pp.13-21
• /
• 1982

Experiments on the eye movement behavior were performed using Vidicon Eye Camera. Factorial design ( $3{\times}3$) was used to evaluate the validity of the eye movement as a performance measure in vigilance task. Eye movement data were recorded in video tapes, then the data were converted to digital signals, which were reduced to quantitative fixation and saccadic movement data by a microcomputer. To compare with existing vigilance performance measures, response time and the number of false alarms were also recorded. The results showed that the saccadic movement is a good measure of the performance in vigilance task : 1. Both the response time and the saccadic movement increased significantly during the initial two time blocks. 2. High correlations were shown between the response time and the saccadic movement. 3. The locational uncertainty affects the saccadic movement, the number of fixations, the response time but doesn't affect the duration of eye fixations.

• Journal of Preventive Medicine and Public Health
• /
• v.48 no.6
• /
• pp.277-279
• /
• 2015

Contact monitoring is an essential component of the public health response to a Middle East respiratory syndrome coronavirus outbreak, and is required for an effective quarantine to contain the epidemic. The timeliness of a quarantine is associated with its effectiveness. This paper provides a conceptual framework to describe the process of contact monitoring, and proposes a new measure called the "timely quarantined proportion" as a tool to assess the adequacy of a public health response.

• The Journal of Korean Academy of Sensory Integration
• /
• v.9 no.1
• /
• pp.45-52
• /
• 2011

Objective : The aim of this study was to provide the method to measure physiologic response using equipments and auditory stimulation, and the physiologic response features of adult psychiatric disorders through a systemic review. Methods : The systemic review was executed using PubMed. The key words for search were "auditory stimulation, auditory startle, electromyograph, skin conductance, heart rate, psychiatric disorder, anxiety disorder, schizophrenia, depression". 8 studies were used for data analysis, and all of levels of evidence were level II. The substances of the review were subject(population), auditory stimulation, measure equipments and physiologic response features of psychiatric disorder. Results : 1. The subjects for the studies were anxiety disorder(4) and schizophrenia(4). 2. Auditory stimulation was used in 8 studies and visual stimulation with auditory stimulation was used in 2 studies to induce physiologic response. 3. Every study used electromyograph, and skin conductance was used in 2 studies and heart rate was used in 2 studies with electromyograph to measure physiologic response. 4. The subjects for the studies, schizophrenia and anxiety disorder(PTSD, OCD) have different physiologic response features with the normal control group. Conclusion : All studies used simple tones as an auditory stimulation and electromyograph to measure physiologic response. Psychiatric disorders indicated larger response, shorter and delayed habituation. The objective and systematic study using physiologic measure to investigate the sensory feature of psychologic disorders.