• The Mathematical Education
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• v.14 no.1
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• pp.11-12
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• 1975

L. Herrington과 P.E. Long이 서술한 H-closed Space에 대해서 성질 즉 H-closed Space의 연속이고 전사인 상은 H-closed Space가 된다는 사실과 그외 몇가지 성질을 조사 했다.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.5
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• pp.472-479
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• 2006

In this research, speciation of phosphorus in sediment and overlying water dependent upon pH and ORP(Oxidation Reduction Potential) was studied. Three possible conditions were simulated: open system with circulation, closed system with stratification and closed system with sand capping on the sediment. Phosphorus release rate from sediment was increased for both open system and closed system if pH was less than 6.0. Phosphorus concentration for closed system was increased from 0.9 mg/L to 0.51 mg/L, and stabilized at 0.34 mg/L if anaerobic conditions were maintained in the overlying water. When sand capping was implemented, phosphorus concentrations of overlying water were maintained less than those of closed system.

• Journal of Korean Neurosurgical Society
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• v.54 no.2
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• pp.112-117
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• 2013

Objective : We performed this study to investigate whether the use of closed-suction drainage following microvascular decompression (MVD) causes cerebrospinal fluid (CSF) leakage. Methods : Between 2004 and 2011, a total of 157 patients with neurovascular compression were treated with MVD. MVD was performed for hemifacial spasm in 150 (95.5%) cases and for trigeminal neuralgia in 7 (4.5%) cases. The mean age of the patients was $49.8{\pm}9.6$ years (range, 20-69). Dural substitutes were used in 44 (28.0%) patients. Ninety-two patients (58.6%) were underwent a 4-5 cm craniotomy using drainage (drainage group), and 65 (41.4%) did a small 2-2.5 cm retromastoid craniectomy without closed-suction drainage (no-drainage group). Results : Eleven (7.0%) patients experienced CSF leakage following MVD based on the criteria of this study; all of these patients were in the drainage group. In the unadjusted analyses, the incidence of CSF leakage was significantly related with the use of closed-suction drainage following MVD (12.0% in the drainage group vs. 0% in the no-drainage group, respectively; p=0.003; Fisher's exact test). Those who received dural substitutes and the elderly (cut-off value=60 years) exhibited a tendency to develop CSF leakage (p=0.075 and p=0.090, respectively; Fisher's exact test). In the multivariate analysis, only the use of closed-suction drainage was significantly and independently associated with the development of CSF leakage following MVD (odds ratio=9.900; 95% confidence interval, 1.418 to infinity; p=0.017). Conclusion : The use of closed-suction drainage following MVD appears to be related to the development of CSF leakage.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.12
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• pp.1732-1739
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• 2017

This paper presents a sensorless vector control algorithm of closed loop Gopinath flux observer to enhance the robustness at low speed by switching P/PI mode. Closed loop Gopinath flux observer has the problem in sensorless vector control of induction motor at low speed. This paper solves the problem using the characteristic function of closed loop Gopinath flux observer. P mode shows better performance than PI mode under the cut-off frequency of observer. But P mode always has a flux error due to DC offset, so this paper combines P mode and PI mode. This algorithm shows good performance over wide speed range. The performance has been confirmed through computer simulations using MATLAB SIMULINK and experiments.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.20 no.2
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• pp.1-7
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• 2014

Purpose: The purpose of this study was to compare the effects of the balance training on the stable and unstable supporting surfaces for the subjects with functional ankle instability. Methods: Twenty-nine subjects with functional ankle instability were randomly assigned to the stable group (n=14) and the unstable group (n=15). Balance training was conducted twenty minutes a day on the stable surface for the stable group and on the airostep for the unstable group three times a week for four weeks. Balance training program was consisted of ten steps by eye opened or closed and two or one leg standing. X-speed for transverse balance and Y-speed for longitudinal balance were measured with eye opened and closed in affected leg standing position. Results: There were significant improvements of balance ability in eye opened (p<.01) and eye closed standing (p<.01) in stable group. Unstable group also showed significant improvements of balance ability in eye opened (p<.01) and eye closed standing (p<.01). There were no statistical differences in the magnitude of improvement between the groups (p<.05). Conclusions: Based on such results, it can be said that balance training on the stable surface is effective as much as training on the unstable surface for the subjects with functional ankle instability.

• Speech Sciences
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• v.15 no.4
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• pp.147-157
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• 2008

Habitual speaking fundamental frequency (sF0) plays an important role in determining the voice classification, which can be presented differently depending on the vocal fold length and language habits. The purpose of this study, therefore, was to compare the differences in sF0 for voice classification and closed quotient between speaking and singing. Seventeen singers (7 sopranos, 5 tenors, 5 baritones, mean age 25.1 years) with no evidence of vocal folds pathology were participated. sF0 and closed quotient (CQ) both in speaking and in singing (A3-A5 with soprano, A2-A4 with tenor and baritone) were measured using SPEAD program and electroglottography. No significant differences were observed for sF0 between tenor and baritone groups (p> 0.05). However, CQ in singing was significantly different among three groups (p< 0.05), but CQ in speaking was not (p> 0.05). Furthermore, CQ was significantly different with both soprano (p< 0.01) and tenor groups ((P= 0.02) whereas baritone group revealed there is no difference when compared between speaking and singing. No significant differences in sF0 between tenor and baritone participants may result from decision-making for voice classification by experience and should measure sF0 before determining the voice classification.

• Bulletin of the Korean Mathematical Society
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• v.60 no.4
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• pp.905-913
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• 2023

Suppose that M is a strictly convex hypersurface in the (n + 1)-dimensional Euclidean space 𝔼ⁿ⁺¹ with the origin o in its convex side and with the outward unit normal N. For a fixed point p ∈ M and a positive constant t, we put 𝚽_t the hyperplane parallel to the tangent hyperplane 𝚽 at p and passing through the point q = p - tN(p). We consider the region cut from M by the parallel hyperplane 𝚽_t, and denote by I_p(t) the (n + 1)-dimensional volume of the convex hull of the region and the origin o. Then Schneider's characterization theorem for ellipsoids states that among centrally symmetric, strictly convex and closed surfaces in the 3-dimensional Euclidean space 𝔼³, the ellipsoids are the only ones satisfying I_p(t) = 𝜙(p)t, where 𝜙 is a function defined on M. Recently, the characterization theorem was extended to centrally symmetric, strictly convex and closed hypersurfaces in 𝔼ⁿ⁺¹ satisfying for a constant 𝛽, I_p(t) = 𝜙(p)t^𝛽. In this paper, we study the volume I_p(t) of a strictly convex and complete hypersurface in 𝔼ⁿ⁺¹ with the origin o in its convex side. As a result, first of all we extend the characterization theorem to strictly convex and closed (not necessarily centrally symmetric) hypersurfaces in 𝔼ⁿ⁺¹ satisfying I_p(t) = 𝜙(p)t^𝛽. After that we generalize the characterization theorem to strictly convex and complete (not necessarily closed) hypersurfaces in 𝔼ⁿ⁺¹ satisfying I_p(t) = 𝜙(p)t^𝛽.

• PNF and Movement
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• v.9 no.1
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• pp.1-9
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• 2011

Purpose : The purpose of this study is to analyze the effect of closed-chain exercise on weight supporting rate change within hemiplegic side and static dynamic balance ability in stroke patients. Methods : The subjects of the study were 13 hemiplegic patients who carried out closed-kinematic chain exercise program over 6 weeks. The exercises of the program are stand to sit with stall bar, stair-up & down by a hemiplegic leg and bridging exercise crossing the non-hemiplegic leg onto the hemiplegic leg. Each exercise was carried out over 3 sets of 10reps. Results : The results of this study were summarized as follows: 1. After intervention, there was a statistically significant change in the weight supporting rate within hemiplegic and non-hemiplegic side(P<0.05). 2. After intervention, there was a statistically significant change in the static balance(FICSIT-4) ability(P<0.05). 3. After intervention, there was a statistically significant change in the dynamic balance(FSST, TUG, FRT) ability(P<0.05). Conclusion : The results of the study suggests that closed-chain exercise program in stroke patients improves their weight supporting rate and enhance the static dynamic balance.

• Journal of the Korean Society of Physical Medicine
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• v.8 no.3
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• pp.369-378
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• 2013

PURPOSE: The purpose of present study was to ascertain how the activity of the serratus anterior muscle, the upper trapezius muscle and the pectoral major muscle was affected while the upper arm was being flexed at 70, 90 and 110 degrees respectively in a closed kinetic chain exercise (wall push up plus) and an open kinetic chain exercise (static hug). METHODS: Sixteen healthy young men subjects participated in the study. Surface electromyography (EMG) data were collected from the dominant-side muscles during a closed kinetic chain exercise and an open kinetic chain exercise. The activity of each muscle was measured quantitatively, and by the use of the two-way repeated ANOVA, the data were compared with each other according to exercises and shoulder flexion angles. RESULTS: Results indicated that the closed kinetic chain exercise did not interact with the open kinetic chain exercise (p>.05). In both the closed kinetic chain exercise and the open kinetic chain exercise, the activity of the serratus anterior muscle became different significantly according to angles (p<.05). Its activity increased in order of 70, 90 and 110 degrees (p<.05). In both exercises and all angles, muscle activity was significantly higher in the serratus anterior muscle than in the upper trapezius muscle and the pectoral major muscle (p<.05). CONCLUSION: The above results show that there is a need to selectively control the exercise stress of the serratus anterior muscle in the case of the patients with the shoulder impingement syndrome characterized by the winged scapula, insufficient scapular protraction and upward rotation.

• Journal of the Korean Society of Physical Medicine
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• v.6 no.1
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• pp.1-8
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• 2011

Purpose : The purpose of this study was to find out the effect of closed kinetic chain exercise with functional electrical stimulation(FES) of the gluteus medius on gait in stroke. Methods : 30 hemiplegic patients voluntarily participated in this study. Subjects were divided into experimental group(n=15) and control group(n=15). Experimental group was given closed kinetic chain exercise with FES of the gluteus medius and control group was given only closed kinetic chain exercise for 4 weeks. All subjects were measured 10m-walking speed, cadence, functional walking category(FAC) and modified motor assessment scale(MMAS) before and after intervention. Results : In experimental group, gait velocity, cadence, FAC and MMAS showed significant difference between pre and post test(p<.05). In control group, gait velocity, cadence and FAC showed significant difference between pre and post test(p<.05). Before intervention, gait velocity, cadence, FAC and MMAS were not significant difference between experimental group and control group(p>.05), but after intervention, gait velocity, FAC and MMAS were significant difference(p<.05). Conclusion : This study show that closed kinetic chain exercise with functional electrical stimulation(FES) of the gluteus medius is beneficial intervention for increase the wlking ability in stroke.