• Communications for Statistical Applications and Methods
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• v.25 no.4
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• pp.329-339
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• 2018

In this study, we propose tests for equality of several variances with the normality assumption. First of all, we propose the likelihood ratio test by applying the permutation principle. Then by using the p-values for the pairwise tests between variances and combination functions, we propose combination tests. We apply the permutation principle to obtain the overall p-values. Also we review the well- known test statistics for the completion of our discussion and modify a statistic with the p-values. Then we illustrate proposed tests by numerical and simulated data and compare their efficiency with the reviewed ones through a simulation study by obtaining empirical p-values. Finally, we discuss some interesting features related to the resampling methods and tests for equality among several variances.

• Korean Journal of Biological Psychiatry
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• v.13 no.3
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• pp.191-201
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• 2006

Objectives : The purpose of this study was to investigate whether the cognitive functions would be correlated with psychotic symptoms and whether antipsychotic treatments would affect the cognitive functions after 8 weeks. Methods : The thirty-five schizophrenic patients were conducted in this study. The psychopathology was measured using PANSS. The memory function, executive function, and sustained attention were measured using Memory Assessment Scale(MAS), Wisconsin Card Sorting Test(WCST), and Vigilance(VIG) and Cognitrone(COG) in Vienna Test System. After 8 weeks of antipsychotic treatment, we retested the cognitive tests. Results : 1) The cognitive tests after the 8 week's treatment showed significant improvements in memory and executive function in the schizophrenic patients. On the other side, sustained attention did not show improvement. 2) The change of PANSS were correlated with perseverative response, perseverative error and total correct in WCST at baseline. WCST scores at baseline were correlated with negative symptoms, but not positive ones. Conclusion : These study suggests that 1) the impaired sustained attention could be a vulnerability marker in schizophrenia, 2) memory & executive function deficit could be reversible after treatment, and 3) medication might have a benefit in improving the cognitive functions in schizophrenia. Furthermore, the data supports that the better premorbid executive function was, the more favorable was the treatment response in schizophrenic patients. Finally, this study indicates that executive function might be an index of treatment improvement.

• Wind and Structures
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• v.37 no.6
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• pp.399-412
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• 2023

Previous studies have shown that the integrated transfer function (ITF) is independent of turbulence characteristics and can be effectively applied to predict the buffeting response of elongated structures, assuming that the strip hypothesis is valid. However, existing research has not effectively identified the ITF through segment model vibration tests, and the influence of the 3D effect on the accuracy of the strip hypothesis and the characteristics of the ITF in wind tunnel tests has not been quantitatively studied. A segment model vibration measurement device that can change a test model's span-width ratio was designed in this study. An airfoil section and a streamlined box girder section structure were taken as the background, and their ITFs were effectively identified under different L/B (L denotes the turbulent integral scale and B denotes the structural width) and model span-width ratios. The influence laws of the 3D effect on the accuracy of the strip hypothesis and ITF identification in wind tunnel tests were systematically investigated. The results showed that L/B and the structural span-width ratio are two significant controlling factors that affect the accuracy of the strip hypothesis and ITF identification. The research provides an effective experimental method for accurately predicting the buffeting response of elongated structures based on ITFs identified through segment model vibration tests.

• Journal of Biomedical Engineering Research
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• v.32 no.2
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• pp.134-143
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• 2011

The selection of meaningful clinical tests and its reference values from a high-dimensional clinical data with imbalanced class distribution, one class is represented by a large number of examples while the other is represented by only a few, is an important issue for differential diagnosis between similar diseases, but difficult. For this purpose, this study introduces methods based on the concepts of both discernibility matrix and function in rough set theory (RST) with two discretization approaches, equal width and frequency discretization. Here these discretization approaches are used to define the reference values for clinical tests, and the discernibility matrix and function are used to extract a subset of significant clinical tests from the translated nominal attribute values. To show its applicability in the differential diagnosis problem, we have applied it to extract the significant clinical tests and its reference values between normal (N = 351) and abnormal group (N = 101) with either cholecystitis or cholelithiasis disease. In addition, we investigated not only the selected significant clinical tests and the variations of its reference values, but also the average predictive accuracies on four evaluation criteria, i.e., accuracy, sensitivity, specificity, and geometric mean, during l0-fold cross validation. From the experimental results, we confirmed that two discretization approaches based rough set approximation methods with relative frequency give better results than those with absolute frequency, in the evaluation criteria (i.e., average geometric mean). Thus it shows that the prediction model using relative frequency can be used effectively in classification and prediction problems of the clinical data with imbalanced class distribution.

• Korean Journal of Psychosomatic Medicine
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• v.11 no.2
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• pp.118-136
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• 2003

Objective: This study is to examine the neuropsychological and developmental characteristics of the Computerized Neurocognitive Function Test among normal children in elementary school. Methods: K-ABC, K-PIC, and Computerized Neurocognitive Function Test were performed to the 120 body of normal children(10 of each male and female) from June, 2002 to January, 2003. Those children had over the average of intelligence and passed the rule out criteria. One-way ANOVA and Bonferroni were used for statistical analysis. Results: In sampling of normal children in elementary school, the control of intelligence level and strict rule out criteria were applied. As a result, although 21.1% were excluded from of total participants, the children that passed the rule out criteria had over the average of intelligence and not differ in the intelligence level among the graders. Comparing Computerized Neurocognitive Function Test results among the graders, almost of variables had significant difference among the graders and especially between the 1st to 2nd and the 5th to 6th graders. In the attention tests, as rising the graders, the performance of tests were improved. In the short-term memory tests, the difference between forward and backward tests were same as the previous research result. The verbal auditory learning test composed of recall task and visual figure memory test composed of recognition task were same as the previous research result using the individual power or achievement test and also as rising the graders, the performance of those tests were improved. The higher cognitive function tests had the same results with other tests. Conclusion: The Computerized Neurocognitive Function Test devised for adult can be used of assessing child neuropsychological characteristics. For this objective, more strict sampling criteria, control of the intelligence and psychopathology were needed.

• Journal of Korean Academy of Oral Health
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• v.42 no.4
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• pp.159-166
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• 2018

Objectives: The aim of this study was to investigate the association between masticatory ability, oral health-related quality of life, and cognitive function in an elderly population using structural equation modeling. Methods: A total of 308 subjects, aged 65 years and over, were recruited from the senior citizen center in Daegu, South Korea and provided consent for inclusion in the study. The Korean version of the Mini-Mental State Examination (K-MMSE) was used to assess the level of cognitive function. Masticatory ability was evaluated through chewing tests, patient-perceived masticatory function and, measurement of relative occlusal forces on molar teeth using the T-Scan $III^{(R)}$ system. All data were analyzed using ${\chi}^2$ tests, t-tests, and one-way ANOVA in SPSS version 23.0 for windows. Structural equation modeling was performed using SPSS AMOS version 22.0. Results: There was a significant association between cognitive function and molar teeth occlusal force. Ability of food chewing score and patient-perceived masticatory function could affect oral health-related quality of life (P>0.05). Higher occlusal forces on molar teeth, compared to anterior teeth, positively correlated with higher cognitive function. Conclusions: These results suggest that an individual's oral health condition could affect molar teeth occlusal forces and may be related to a risk of developing dementia. Therefore, there is a need for implementing nation-wide policies to improve oral health, such as masticatory function, in the elderly population.

• Archives of Reconstructive Microsurgery
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• v.24 no.1
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• pp.28-31
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• 2015

A case report of a patient who developed radiation-induced sarcoma in the left chest wall is presented. The patient had partial mastectomy and adjuvant radiation therapy (total dose, 5,220 cGy) and chemotherapy. Five years later, she visited with rapidly growing mass with central ulceration in the irradiated chest wall. The mass was diagnosed as malignant fibrous histiocytoma. The chest wall mass resected en bloc ($23{\times}18cm$) including five consecutive ribs. After the defected thoracic cage was reinforced using a polytetrafluoroethylene patch, omental flap and split thickness skin graft was done for soft tissue coverage. We applied negative pressure wound closer system for effective suction of omeantal exudate. The wound healed without complications. The patient suffered no perioperative pulmonary complications. Pulmonary function tests showed no significant changes. Each of Gore-Tex, omental flap, negative pressure wound therapy and skin graft is widely used method. However, If these methods are used in combination, we can reconstruct the large defect of chest wall including multiple ribs without any repiratory function problems.

• Perspectives in Nursing Science
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• v.9 no.1
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• pp.45-50
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• 2012

Purpose: Despite poor cognitive function in heart failure (HF), few studies have examined cognition and its probable implication in self-care among Korean HF patients. The purposes of this study were (1) to describe cognition in the domains of global, memory, and executive functions, (2) to explore the relationship between cognition and self-care, and (3) to determine the amount of dietary sodium intake among Korean HF patients. Methods: A pilot study was conducted: 7 HF patients (3 men, mean age 68 years) completed face-to-face interviews for neuropsychological tests of cognition and self-care including dietary sodium intake. Results: More than half of the patients had impaired global cognition, memory, or executive function; patients with more severe HF were at higher risk of poor cognitive function. Korean HF patients exhibited poor self-care, with a high dietary sodium intake (5.6 g/day), approximately twice more than the suggested guideline of 2~3 g/day for patients with stable HF. Conclusion: Cognitive dysfunction and inadequate self-care with noncompliance with dietary sodium restriction were evident in Korean HF patients. More studies are warranted that examine the prevalence of cognitive impairment and areas of deficit using neuropsychological tests in a larger sample and that examine how cognition affects self-care and compliance in salt-intake.

• Physical Therapy Korea
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• v.19 no.3
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• pp.72-80
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• 2012

The purpose of the present study was to investigate the effects of familiar exercise and novel exercise on motor function after intracerebral hemorrhage (ICH) in rats. The rats were subjected to a unilateral striatal ICH via collagenase infusion. The rats were randomly divided into the following three groups: the CON (control group; rested one week post-ICH), the FE (familiar exercise group; familiar exercise was performed two weeks after one-week post-ICH period), and NE (novel exercise group; novel exercise was performed two weeks after one-week post-ICH period). We measured neurological behavior using a ladder rung walking test and a beam walking test; we measured the level of nerve growth factor (NGF) using immunohistochemistry and western blot analysis. We performed a one-way ANOVA test to analyze the scores obtained from the neurological behavior tests and the differences of NGF protein levels among the three groups. In the present study, the FE group and the NE group showed significant improvement during the neurological behavior tests and in their expression of NGF protein level, as compared to the CON group. Especially, NE group more increase than FE group in neurological behavior tests, the expression of NGF on motor cortex. In conclusion, these results suggest that, after ICH, familiar exercise and novel exercise enhance motor function and, novel exercise is more effective than familiar exercise.

• Transactions of the Korean Society of Automotive Engineers
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• v.8 no.3
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• pp.110-118
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• 2000

For reasonable fatigue design and estimation of fatigue durability considered fatigue strength and stiffness of the automotive body structure, many fatigue data must be insured according to the shapes, materials, and welding conditions of the spot welded lap joints. However, because it is actually difficult problem, there is need to establish a new method to be able to predict its fatigue life without any additional fatigue tests. Therefore, In order to improve such problems, in this study, the maximum stress function presenting the $\delta\sigma_{1max}―\delta P$ relation was defined form the relation between $\delta\sigma_{1max}-N_f$ and ${\delta}P-N_f$. By using the fatigue data on the IB type spot-welded lap joints previously obtained from the fatigue test results, fatigue life of the spot-welded lap joint previously obtained from the fatigue test results, fatigue life of the spot-welded lap joint having a certain dimension was tried to predict without any additional fatigue tests. And, its result was verified by ${\delta}P-$N_f$ curves. Obtained conclusion are as follows, 1) a maximum stress function considered the relation of the maximum principal stress, fatigue load, and the effects of geometrical factors of the IB type spot-welded lap joint was suggested. 2) the fatigue life predicted by the maximum principal stress function and the relation of $\delta\sigma_{1max}-N_f$ was well agreed with the fatigue life obtained through the actual fatigue test result. 3) the fatigue life of the IB type spot-welded lap joint having a certain dimension is able to be predicted without any additional fatigue tests from the fatigue life prediction method by the maximum principal stress function.