• Dementia and Neurocognitive Disorders
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• v.21 no.4
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• pp.138-146
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• 2022

Background and Purpose: Magnetic resonance imaging (MRI) helps with brain development analysis and disease diagnosis. Brain volumes measured from different ages using MRI provides useful information in clinical evaluation and research. Therefore, we trained machine learning models that predict the brain age gap of healthy subjects in the East Asian population using T1 brain MRI volume images. Methods: In total, 154 T1-weighted MRIs of healthy subjects (55-83 years of age) were collected from an East Asian community. The information of age, gender, and education level was collected for each participant. The MRIs of the participants were preprocessed using FreeSurfer(https://surfer.nmr.mgh.harvard.edu/) to collect the brain volume data. We trained the models using different supervised machine learning regression algorithms from the scikit-learn (https://scikit-learn.org/) library. Results: The trained models comprised 19 features that had been reduced from 55 brain volume labels. The algorithm BayesianRidge (BR) achieved a mean absolute error (MAE) and r squared (R²) of 3 and 0.3 years, respectively, in predicting the age of the new subjects compared to other regression methods. The results of feature importance analysis showed that the right pallidum, white matter hypointensities on T1-MRI scans, and left hippocampus comprise some of the essential features in predicting brain age. Conclusions: The MAE and R² accuracies of the BR model predicting brain age gap in the East Asian population showed that the model could reduce the dimensionality of neuroimaging data to provide a meaningful biomarker for individual brain aging.

• Journal of the Korea Institute of Military Science and Technology
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• v.27 no.5
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• pp.544-557
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• 2024

This paper theoretically analyzes the effect of the velocity and attitude errors of Master Inertial Navigation System(MINS) on the accuracy of Slave Inertial Navigation System(SINS) transfer alignment in velocity and attitude matching, and validates the analysis through simulation. Theoretical analysis involves deriving a new state equation that considers the velocity and attitude errors of MINS from the state equation of the transfer alignment filter, and deriving the state estimation equation of the Kalman filter based on this. The analysis confirms that MINS's velocity and attitude errors induce the same level of velocity and attitude errors in SINS. A reference inertial navigation system model is added to the simulation model, and the transfer alignment accuracy is analyzed by comparing the navigation information of MINS and SINS with the reference inertial navigation system. It is confirmed that the accuracy analysis results through simulation are consistent with the theoretically analyzed results, and through this, the validity of the theoretically analysis in this paper is verified. The research findings indicate that when performing transfer alignment using MINS, which is likely to be operated for prolonged periods in pure inertial navigation mode, the navigation errors of MINS are transferred to SINS. This implies that initial correction navigation is necessary to be considered for SINS

• Journal of the Korean Society of Physical Medicine
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• v.19 no.3
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• pp.55-63
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• 2024

PURPOSE: This study examined the test-retest reliability and clinical utility of the Modified Trunk Impairment Scale (mTIS), Trunk Control Test (TCT), and Postural Assessment Scale for Stroke - Trunk Control (PASS-TC) in patients with chronic stroke. METHODS: Thirty-eight stroke patients were reassessed using the mTIS, TCT, and PASS-TC with a seven-day interval between assessments. The test-retest reliability was evaluated using the intraclass correlation coefficient (ICC_2,1), the standard error of measurement (SEM), the minimal detectable change (MDC), and MDC%, as well as Bland-Altman analysis. The relationship between the mTIS, TCT, PASS-TC scores, and the Barthel Index (BI) was also investigated. RESULTS: The test-retest reliability for the mTIS, TCT, and PASS-TC was high, with ICC values ranging from .91 to .94 (95% confidence interval: .83-.97). The MDCs for the mTIS and TCT were 2.35 and 13.9, respectively, while the MDC for the P ASS-TC was 2.54, all below 20% of the maximum possible score, indicating reliable measurement. The optimal mTIS cut-off score for distinguishing between mild (75-95 points) and severe (50-74 points) dependence on the BI was ≥ 9.5, with an accuracy of 79%. Patients with an mTIS score ≥ 9.5 (out of 15) showed an 18-fold higher likelihood of achieving a mild level of functional independence than those with a score < 9.5. CONCLUSION: The mTIS, TCT, and PASS-TC showed high test-retest reliability and no systematic errors in chronic stroke patients. The MDC values were reliable, indicating meaningful change. Among these, the mTIS is a sensitive and a useful tool for predicting functional independence in clinical practice and is straightforward to apply.

• The Journal of the Korea institute of electronic communication sciences
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• v.19 no.5
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• pp.853-860
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• 2024

In this study, a design method for a PWM control-based single input/single output buck DC-DC converter with multiple output voltages was studied which is recently required in industrial electronic devices. Based on the basic theory of the buck DC-DC converter, the design method of the buck converter was determined and a voltage control algorithm based on PWM control for a single-input, single-output buck converter that can selectively obtain multi-level output voltages was developed. To verify the effectiveness of the design methodology, a prototype was designed and made. Next, under a test environment based on the prototype DC-DC converter, the effectiveness of the PWM control-based voltage control method was verified by confirming that the multiple output voltages track within an error rate of 7% when the target voltages are selectively determined for the fixed and variable input voltages.

• Journal of Korean Academy of Nursing Administration
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• v.1 no.2
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• pp.268-284
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• 1995

This study was designed to test effects of nursing ethics education (NEE) on moral reasoning and ethical decision making of subjects. This NEE that was teached for 10 hours course was composed of these : Nurses' ethical code, moral responsibility, Moral value and professional accountability, Respect for human life, General ethics, Theory and Norms of biomedical ethics, Ethical decision making model and Discussion about hypothetical ethical dilemmas Twenty-five senior student nurses were sampled from four year college of nursing from Nov. 3rd, 1993 to Nov. 24th, 1993. Data were collected through self-reported questionnaires included two kinds of tests. Rest's Defining Issues Test was adopted to measure the stage of moral development, which was classified with the stage 2 (instrumental relativist orientation), the stage 3 (interpersonal concordance), the stage 4 (law and order), the stage 5A (societal consensus), and the stage 5B (intuitional humanism), the stage 6 (universal ethical practice). In particular, the level of principled thinking (P) was measured by summing these scores of the stages 5A, 5B, and 6. The possible range of P is 0 to 95. As for measuring the levels of morality and nursing dilemma, Crisham's Nursing Dilemma Test was adopted. This test generated the morality score(MS) and the dilemma score (DS). The data were analyzed by t-test, ANOVA, Kruskal-Wallis test, Mc Nemar's test and Pearson correlation coefficients. The results were as follows ; 1. For the Moral Reasoning both before and after NEE, The Mean score of the stage 5A was significantly higher than that of other stages.(P=0.0001) Before NEE, the mean score of the stage 4 was significantly different from stage 2, 3, 5A, and after NEE, different from stage 2, 5B,6. 2. The analysis of change of moral development level revealed that the score of stage 4 increased after NEE.(P=0.0004) 3. The Effect of NEE for the mean score of 5A, 6, P after education was significantly different by birth place. 4. With regard to the five dilemmas postulated such as forcing medication performing cardiac pulmonary resuscitation, reporting a medication error, informing diagnosis to terminally ill adult, and providing new-nurse orientation, the mean score of the MS and the DS was no significant difference with general characteristics of the students. Effect of NEE morality score and dilemma score after education was no significant difference. 5. As for the correlations between moral reasoning and decision making, the score of the stage 2, 5A, 6, DS was positively correlated with the scores of before and after. Positive correlation was also observed between the scores of stage 2 and stage 4, stage 3 and 6. On the other hand, the score of P was negatively correlated with the scores of stage 2 and of stage 4 and of stage 5A. The score of the stage 5A was also negatively correlated with the score of the sge 6.

• IMMUNE NETWORK
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• v.1 no.2
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• pp.104-108
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• 2001

Aging is a senescence and defined as a normal physiologic and structural alterations in almost all organ systems with age. As Leonard Hayflick, one of the first gerontologists to propose a theory of biologic aging, indicated that a theory of aging or longevity satisfies the changes of above conditions to be universal, progressive, intrinsic and deleterious. Although a number of theories have been proposed, it is now clear that cell aging (cell senescence) is multifactorial. No single mechanism can account for the many varied manifestations of biological aging. Many theories have been proposed in attempt to understand and explain the process of aging. Aging is effected in individual by genetic factors, diet, social conditions, and the occurrence of age-related diseases as diabetes, hypertension, and arthritis. It involves an endogenous molecular program of cellular senescence as well as continuous exposure throughout life to adverse exogenous influences, leading to progressive infringement on the cell's survivability so called wear and tear. So we could say the basic mechanism of aging depends on the irreversible and universal processes at cellular and molecular level. The immediate cause of these changes is probably an interference in the function of cell's macromolecules-DNA, RNA, and cell proteins-and in the flow of information between these macromolecules. The crucial questions, unanswered at present, concerns what causes these changes in truth. Common theories of aging are able to classify as followings for the easy comprehension. 1. Biological, 1) molecular theories - a. error theory, b. programmed aging theory, c. somatic mutation theory, d. transcription theory, e. run-out-of program theory, 2) cellular theories - a. wear and tear theory, b. cross-link theory, c. clinker theory, d. free radical theory, e. waste product theory, 3) system level theory-a. immunologic/autoimmune theory, 4) others - a. telomere theory, b. rate of living theory, c. stress theory, etc. Prevention of aging is theoretically depending on the cause or theory of aging. However no single theory is available and no definite method of delaying the aging process is possible by this moment. The most popular action is anti-oxidant therapy using vitamin E and C, melatonin and DHEA, etc. Another proposal for the reverse of life-span is TCP-17 and IL-16 administration from the mouse bone marrow B cell line study for the immunoglobulin VDJ rearrangement with RAG-1 and RAG-2. Recently conclusional suggestion for the extending of maximum life-span thought to be the calory restriction.

• Journal of Animal Environmental Science
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• v.13 no.2
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• pp.105-112
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• 2007

This research was carried out to test and analyse the capability of a fan for development of a sprayer in actual livestock farm. A fan was designed and made to be able to spray agricultural chemicals within 140mm in a maximum scattering range and 100m in an effective scattering range. Accordingly, its' flow rate was $3,600\;m^3/min$, and static pressure was 100 mmAq for a wide area sprayer to be sprayed widely and far. Fan performance, which was given $600\;m^3/min$ flow rate and 500 mmAq total pressure, was tested fur basic experiment. As the result, the axial power showed minimum error, which be designed to keep the fan performance. And power efficiency was the maximum. Sound level was 92.1dB that wasn't enough to environmental standard. If we take the sealed place into consideration, sound level is suitable for environmental standard.

• Journal of Korean Academy of Nursing Administration
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• v.5 no.3
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• pp.425-444
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• 1999

The purpose of this study is to survey evaluation of the nurse on the current Performance Appraisal System. the need for future performance of the nurse and the opinions about the job rotation, and suggest the direction of improvement by obtaining basic data to improve personnel management of the nurse in a hosipial, the subject of the investigation. The study was conducted self-reporting questionniare survey of 330 nurses working at C hospital located in Chonbuk Province and the data was collected from May 4. 1999 through May 14. The research used measuring instrument developed by researcher for evalution about the present performance appraisal. the need for the future performanc appraisal system and the opinion of job rotaion. The analysis of the collected data was computerized using SPSS/PC+ program, calculated frequency, percentage, the mean and standard deviation and used Pearson, s Correlation Coefficients, t-test, chi- square test. Major findings are as follows. 1) As for the purpose of the current performanc appraisal, the appraiser recognized it as a security of promotion standard, while the employee saw it as a means for control as guidance and supervison of work. 2) With regard to use the result of the present performance appraisal, appraiser picked ambiguous appraisal standard, employees recognized unilateral evaluation of superior eliminated the participation of them as the highest priority. 3) In relation to the current criteria for promotion of the nurse, both appraisers and employees placed more weight on the length of clinical than performance appraisal score. 4) There is much possibility of the appraiser making an error to evaluate considering the length of performance appraisal. 5) Both appraisers and employees indicated that prospective result of performance appraisal should be used for the ability development & motivation of the individual. 6) Concerning employee's participation for performance appraisal both sides wanted by far more participation. 7) Regarding the most ideal appraisal method, both parties favored most the way added up the evaluation of the head nurse and peer review and followed by the manner the revaluation of the head nurse by considering self-evaluation. 8) As to the individual interview after the appraisal, more than 60% of appraisers responded it's not necessary, while above 88.5% of employees answered it is essential so that it is showed significantly difference between the appraisers and the employees. 9) As far as open of the evaluation result is concerned. 75% of the appraiser were against it but 80% of the employee were for it so that it showed significantly between them. The most principal reason that the employee want is that it motivates the individual's ability development and the fairness of the appraisal increases. 10) Whether the periodical rotation is necessary or not, 80% of appraisers and employees answered it's necessary, however, over 70% of them did not want the rotation. 11) Work-group Cohesiveness level within the nursing unit was attentive different from desire of the rotation, that is, the work group cohesiveness level of nurses wanting rotation was significantly lower than that of the group not desiring it.

• Journal of Biomedical Engineering Research
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• v.25 no.3
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• pp.189-194
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• 2004

Pixel values of contrast enhanced computed tomography (CE-CT) images are randomly changed. Also, the middle liver part has a problem to segregate the liver structure because of similar gray-level values of a pancreas in the abdomen. In this paper, an automatic liver segmentation method using a partial histogram threshold (PHT) algorithm is proposed for overcoming randomness of CE-CT images and removing the pancreas. After histogram transformation, adaptive multi-modal threshold is used to find the range of gray-level values of the liver structure. Also, the PHT algorithm is performed for removing the pancreas. Then, morphological filtering is processed for removing of unnecessary objects and smoothing of the boundary. Four CE-CT slices of eight patients were selected to evaluate the proposed method. As the average of normalized average area of the automatic segmented method II (ASM II) using the PHT and manual segmented method (MSM) are 0.1671 and 0.1711, these two method shows very small differences. Also, the average area error rate between the ASM II and MSM is 6.8339 ％. From the results of experiments, the proposed method has similar performance as the MSM by medical Doctor.

• Tuberculosis and Respiratory Diseases
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• v.79 no.4
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• pp.295-301
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• 2016

Background: Specific immunoglobulin E (IgE) sensitization to staphylococcal enterotoxin (SE) has been recently considered to be related to allergic disease, including asthma. Despite studies on specific IgE (sIgE) to SE and its relationship to asthma diagnosis and severity, the association of sIgE to SE with airway hyperresponsiveness (AHR) remains unclear. Methods: We enrolled 81 asthma patients admitted to the Severance Hospital in Korea from March 1, 2013, to February 28, 2015 and retrospectively reviewed the electronic medical records of the enrolled subjects. The serum levels of sIgE to SE (A/B) of all subjects was measured using the ImmunoCAP 250 (Phadia) system with SE-sIgE positive defined as >0.10 kU/mL. Results: The SE-sIgE level was not significantly correlated with asthma severity (forced expiratory volume in 1 second [$FEV_1$], $FEV_1$/forced vital capacity, sputum eosinophils, and serum eosinophils), whereas the SE-sIgE level in patients with positive AHR ($mean{\pm}standard$ error of the mean, $0.606{\pm}0.273kU/mL$) was significantly higher than that in patients with negative AHR ($0.062{\pm}0.015kU/mL$, p=0.034). In regression analysis, SE sensitization (sIgE to SE ${\geq}0.010kU/mL$) was a significant risk factor for AHR, after adjustment for age, sex, $FEV_1$, and sputum eosinophils (odds ratio, 7.090; 95% confidence interval, 1.180-42.600; p=0.032). Prevalence of SE sensitization was higher in patients with allergic rhinitis and non-atopic asthma patients, as compared to patients without allergic rhinitis and atopic asthma patients, respectively, but without statistical significance. Conclusion: SE sensitization is significantly associated with AHR.