• Journal of the Korean Mathematical Society
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• v.33 no.2
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• pp.249-258
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• 1996

Analysis by the method of characteristics shows that if f and $u_0$ are smooth and $u_0$ has compact support, then the Hamilton-Jacobi equation $$ (H-J) ^{u_t + f(u_x) = 0, x \in R, t > 0, } _{u(x, 0) = u_0(x), x \in R, } $$ has a unique $C^1$ solution u on some maximal time interval $0 \leq t < T$ for which $lim_{t \to T}u(x, t) exists uniformly; but this limiting function is not continuously differentiable.

• Journal of the Korean Mathematical Society
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• v.45 no.3
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• pp.757-769
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• 2008

This paper deals with the existence of optimal controls and maximal principles for semilinear evolution equations with the nonlinear term satisfying Lipschitz continuity. We also present the necessary conditions of optimality which are described by the adjoint state corresponding to the linear equations without a condition of differentiability for nonlinear term.

• Journal of the Korean Mathematical Society
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• v.46 no.3
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• pp.577-588
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• 2009

In this paper, the author studies the k-th commutators of oscillatory singular integral operators with a BMO function and phases more general than polynomials. For 1 < p < $\infty$, the $L^p$-boundedness of such operators are obtained provided their kernels belong to the spaces $L(log+L)^{k+1}(S^{n-1})$. The results of the corresponding maximal operators are also established.

• East Asian mathematical journal
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• v.21 no.1
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• pp.41-48
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• 2005

In this paper we first introduce a space of homogeneous type X, and then consider a kind of generalized upper half-space $X{\times}(0,\;\infty)$. We are mainly considered with inequalities for the $L^p$ norms of area functions associated with approach regions in $X{\times}(0,\;\infty)$.

• Communications for Statistical Applications and Methods
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• v.20 no.4
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• pp.241-246
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• 2013

In this study, we propose a nonparametric simultaneous test procedure for the location translation and scale parameters. We consider the Wilcoxon rank sum test for the location translation parameter and the Mood test for the scale parameter with the quadratic and maximal types of combining functions. Then we derive the limiting null distributions of the combining functions. We illustrate our procedure with an example and compare efficiency by obtaining the empirical powers through a simulation study. Finally, we discuss some interesting features related to the nonparametric simultaneous tests.

• Journal of the Korean Society of Physical Medicine
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• v.6 no.4
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• pp.437-445
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• 2011

Purpose : The purpose of this study was to analysis on diaphragm thickness and lung function of stroke patients by walking ability. Methods : We recruited thirty-five adults after stroke(20 male, 15 female) for our study. The subjects were divided into two groups; independent walking group(11 male, 9 female) and non-independent walking group(9 male, 6 female). Assessment of diaphragm thickness was performed using ultrasound in B-mode with a 7.5 MHz linea probe. During the experiment, the subject was seated in the chair. All subjects performed maximal expiratory flow maneuvers using a spirometer in order to determine the forced expiratory volume in 1 second ($FEV_1$), forced vital capacity(FVC), peak expiratory flow(PEF) and $FEV_1$/FVC. Chest expansion was measured with a tape-measure placed circumferentially around the chest wall at the xiphoid process. The collected data analyzed by independent t-test. Results : The diaphragm thickness were significant differences between the independent walking and nonindependent walking group. Values of forced vital capacity, forced expiratory volume at one second, peak expiratory flow in pulmonary function tests were significant differences between the independent walking and non-independent walking group. However, chest expansion were not significant differences in both of the group. Conclusion : This study showed that walking ability of stroke patients have influenced on diaphragm thickness and pulmonary function.

• Proceedings of the KOSOMBE Conference
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• v.1992 no.05
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• pp.203-208
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• 1992

In order to restore the gait function by functional electrical stimulation(FES) in hemiplegic patients, an electrical stimulator and foot sensor were developed on the basis of optimal parameters which resulted from animal experiments. Physical properties of the soleus muscle were quite different from those of themedial gastrocnemius muscle, that is, the former had a characteristic or slow muscle and the letter had a characteristic of fast muscle in rats. Optimal parameters for electrical stimulation were 0.2ms of pulse width and 20Hz of frequency in the soleus muscle and 0.3ms, 40Hz in the medial gastrocnemius muscle. Amplitude modulated electrical stimulator with -15V of maximal output was made and automatic on-off time if the stimulator was 5 seconds. The foot sensor composed of 3 sensors in 3 pressure points of the foot was made in order to control the gai t function by closed loop feedback system. The gait function was improved by using the stimulator and foot sensor in peroneal palsy. These results suggest that the electrical stimulator with closed loop feedback system may restore the gait function in hemiplegic patients.

• Journal of Chest Surgery
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• v.27 no.7
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• pp.587-597
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• 1994

To study the recovery pattern of pulmonary function after decortication, the author performed serial pulmonary function tests using spirometry before and at lst., 3rd., 4th. week, lst., 3rd., 6th. month and 1st. year in 36 patients who underwent decortication from January 1989 to September 1991 at the Department of Thoracic and Cardiovascular Surgery, Pusan National University Hospital, Pusan, Korea. Patients were divided into 3 groups by the degree of compression of lung parenchyme. Group I was classified below 20%, Group II between 21 to 40%, Group III above 41%. Their serial changes of pulmonary function test were compared. The obtained results were as follows; 1. Maximal voluntary ventilation was recovered in 1st post perative week and even greater improvement was noted in group III in which ratio to 44 % of the preoperative value. 2. Vital capacity reached nearly to preoperative values in 3rd postoperative week and had increased much further to 26 % above the preoperative figure in group II. 3. Forced expiratory volume in 1 second returned rather slowly in 3rd-4th postoperative week and the mean VC was improved more higher in group II than the other groups following decorti cation. 4. There was an greatest improvement over all tests[MW, VC, FEV1] in 2nd decade which ratios to preoperative value were 34, 25 and 22 % respectively.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.11 no.1
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• pp.64-68
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• 2000

Background and Objectives : To assess the role of altered vocal function in transient voice change after short-term endotracheal intubation, we evaluated acoustic parameters, aerodynamic parameters, and laryngoscopic characteristics preoperatively and postoperatively. Materials and Methods : Vocal function of 10 patients undergoing tympanoplasty and mastoidectomy using general anesthesia and endotracheal intubation were studied preoperatively, at 1day and 7 days after extubation. Acoustic analysis, aerodynamic study, and telescopic examination were used to assess vocal function. Results : In acoustic parameters, there was no significant difference between preoperative and postoperative measures. However, in subglottic pressure, ere was a significant decrease at 1 day after extubation and this change was return to preoperative value at 7 days after extubation. MPT(Maximal Phonation Time), MER(Mean flow Ratio), and VC(Vital Capacity) were decreased 1 day after extubation but did not show statistically significant change. Three of 10 patients manifested a vocal fold edema and injection 1 day after extubation. Conclusions : Subglottic pressure revealed a significant decrease at 1 day after extubation. And this change was correlated with laryngeal morphologic change and decrement in pulmonary function.

• Journal of the Korea Convergence Society
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• v.10 no.6
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• pp.95-101
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• 2019

The purpose of this study was to determine whether PNF respiratory convergence exercise increases the pulmonary function of normal adults by $45^{\circ}$ leaning sitting position. Twenty normal adults in their 20s were randomly assigned to an experimental group (n=10) or control group (n=10). Over the course of four weeks, the experimental group participated in PNF respiration exercises by $45^{\circ}$ leaning position for 30 minutes three per week. And the control group participated in PNF respiration exercises by supine position for 30 minutes three times per week. Subjects were assessed pre-test and post-test by measurement of pulmonary function. Our findings show that the experimental group had significant improvements in expiratoy reserve volume and vital capacity, maximal voluntary volume. In this study, the experimental group showed greater improvement in pulmonary function than the control group, which indicates that the PNF respiratory exercise by $45^{\circ}$ leaning sitting position is effective at increasing the pulmonary function of normal adults.