• Bulletin of the Korean Mathematical Society
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• v.54 no.1
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• pp.177-186
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• 2017

In this paper, a type of Riemannian manifold (namely, pseudo semiconformally symmetric manifold) is introduced. Also the several geometric properties of such a manifold is investigated. Finally the existence of such a manifold is ensured by a proper example.

• Proceedings of the SAREK Conference
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• 2004.11a
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• pp.18-18
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• 2004

• Journal of applied mathematics & informatics
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• v.24 no.1_2
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• pp.65-79
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• 2007

An optimal 3-point quadrature formula of closed type is derived. It is shown that the optimal quadrature formula has a better error bound than the well-known Simpson's rule. A corrected formula is also considered. Various error inequalities for these formulas are established. Applications in numerical integration are given.

• Communications of the Korean Mathematical Society
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• v.36 no.3
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• pp.485-494
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• 2021

In this article, we prove the existence of a solution to some classes of integral equations of generalized convolution type generated by the Kontorovich-Lebedev (K) transform, the Laplace (𝓛) transform and the Fourier (F) transform in some appropriate function spaces and represent it in a closed form.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.28B no.10
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• pp.771-782
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• 1991

In industrial multivariable plants, it is ofte the case that the plant outputs are measured in similar components not simultaneously but serially. In this paper, the problem of estimating the state vector of the plant based on the data obtained from such a measuring scheme is considered, and a special type of observer(referred to as a $'$multiple serial-sampling$'$ type observer) which renews its internal states whenever a new group of data is obtained is proposed. It is proved that such an observer can be constructed for almost every sampling period if the palnt is observable as a continuous-time multivariable system, and that the poles of the closed-loop system using the multiple serial-sampling type observer consist of the poles of the observer and those of the state feedback system. The behaviors of the observer and the closed-loop system are studied by simulation. The results of simulation indicate that a multiple serial-ampling type observer can estimate the state of the plant more accurately than the ordinary type observers and improve the closed-loop performance, especially, in the existence of measuring noise.ng noise.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.565-569
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• 2004

The wing-body trucks are special vehicles that are designed to provide large carrying space and to protect the freights from outside impacts and bad weather. They are constructed to the structure opening and shutting three-layered aluminum top. In the middle- and large-size(above one-ton) wing-body trucks, wing-body is opened/closed by opening and shutting device of oil pressure type. But one-ton truck is constructed that its wing-body is opened/closed in manual to use helping of stay-dampers. So, we developed an electronic opening and shutting device for one-ton wing-body trucks to improve the inconvenience of usage for manually operated wing-body. The developed device is consisted of two connected links and a dc motor combined with an worm gear. The worm gear changes the rotation axis of the dc motor to a right-angled direction and transfers the torque of dc motor to the links. The two connected links open/shut the wing-body using the torque transferred from the dc motor. When the wing-body starts to be opened, the biggest torque is required from the dc motor for opening the wing-body. And as the wing-body is opened more and more, the required torque is smaller for opening the wing-body. Thus, the structure of two connected links are designed to locate at the center of worm gear so that maximum torque of the dc motor is transferred the links at the initial time starting to open wing-body. The controller of the device with open and closed buttons also is designed to protect the device from over-opening and over shutting operations. The developed device is accomplished for many experiments using actual vehicle. Those experiments show that the device has more excellent performance than the oil pressure type.

• Physical Therapy Korea
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• v.10 no.3
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• pp.1-15
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• 2003

The purpose of this study was to assess the effect of visual block (eyes open or closed), mental task type, and participation in an exercise program on static balance in the elderly. The subjects were 34 elderly (>65 years old) residents of a social welfare institute in Gyeonggi-do. We measured the following variables. Berg balance scale, mini mental state examination, balance performance monitor (sway area, path, and maximal sway velocity), age, weight, height and whether the subject participated in an exercise program. Scores for the Berg balance scale and mini mental state examination were evaluated to assess static balance ability either alone (single task paradigm) or while performing a mental task (dual task paradigm). Static balance variables that were measured included sway area, path, and maximal sway velocity. Each test was repeated three times. Multiple regressions analysis was used to examine the effect of each variable on static balance ability. For the dual task paradigm, static balance was affected by whether the subject participated in an exercise program. The Berg balance scale score for subjects with their eyes open was affected by whether they participated in an exercise program, while this variable in addition to the height and weight of subjects were determining variables in subjects with their eyes closed. As a result, whether subjects participated in an exercise program affected their static balance irrespective of whether their eyes open or closed. Therefore, regular exercise is recommended for elderly people and further research is needed to examine the relationship between static and dynamic balance while performing mental tasks such as cognition and attention.

• Journal of Chest Surgery
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• v.12 no.3
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• pp.174-182
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• 1979

This is a report on four cases of successful surgical correction of coarctation of the aorta [COA] in Department of the Thoracic & Cardiovascular Surgery, Hanyang University Hospital. The first case was a postductal type of coarctation of the aorta associated with Patent ductus arteriosus [PDA], Persistent left superior vena cava [LSVC] and richly developed collateral circulation. Blood pressure was measured to be hypertensive at the arm, but hypotensive at the legs. The coarctation of the aorta was corrected with following procedure: Partial resection of the aortic wall with diaphragmatic structure lust above and below the coarctating line of the aorta, and then the defect of the aortic wall was closed by lateral aortographic suture. PDA was closed by ligation procedure. The second case a preductal type of coarctation of the aorta associated with PDA, LSVC, ventricular septal defect [VSD] and poorly developed collateral circulation. Normal blood pressure was measured at the arm, but hypotension was observed at the legs. Correction of coarctation of the aorta was performed under the establishment of tube bypass because of poor collateral circulation. After resection of coarctating short segment, end to end anastomosis was performed without any tension. PDA was closed by division procedure. Simple suture closure of VSD was performed by open heart surgery two weeks after correction of COA. The third case was a long segment COA without any other anomaly. Blood pressure was measured to be hypertensive at the arm, but hypotensive at the legs. Vascular prosthesis was performed using Teflon graft tube after resecting coarctating long segment [6.5 cm] of the aorta. The fourth case was a long segment COA associated with aortic insufficiency and richly developed collateral circulation. Normal blood pressure was measured at the arm, but hypotension was observed at the legs. Vascular prosthesis was performed using Teflon graft tube after resecting coarctating long segment [6.0 cm] of the aorta. Both blood pressure and peripheral pulse on the arm and the legs returned to normal postoperatively in all patients.

• The Journal of Korean Physical Therapy
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• v.29 no.5
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• pp.287-291
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• 2017

Purpose: This paper provides basic clinical data on the treatment of scoliosis patients by analyzing the effects of the type and position of scoliosis on the static balance using Tetrax on adolescents who have balance disorders as a consequence of structural changes, such as scoliosis. Methods: A total of 110 adolescents were divided into 6 groups according to the radiographs and 60 adolescents were sampled, 10 each for each group. The static balance was measured and analyzed on the existence of sight using Tetrax. Results: The changes followed by existence of sight in static balance group showed a significant difference statistically in Stability index in all groups (p<0.001). The changes in the static balance in each group in terms of the stability index were significant in all groups, where the experiments were performed under the eyes opened and eyes-closed condition (p<0.01)(p<0.001). The post-hoc comparison revealed the stability index to be the highest in the eyes-opened condition in group III, but not in group IV. In the eyes-closed condition, group III showed the highest stability index of all the groups. Conclusion: Adolescents with lumbar scoliosis had a lower static balance in single scoliosis with the eyes-closed condition or had little movement compensation. In addition, unlike the other normal scoliosis, back scoliosis has negative effects on the posture because it causes an increase in the disturbance of posture. Therefore, future studied will be needed to examine the imbalance of posture in people suffering from back pain.

• The Journal of Sustainable Design and Educational Environment Research
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• v.19 no.4
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• pp.1-14
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• 2020

This study is to make suggestions on the type and operation of community life SOC projects suitable for the use of idle facilities in elementary and secondary schools. To this end, we analyzed the types and operation of desirable utilization facilities according to regional characteristics through the analysis of cases utilizing Japanese idle classrooms and closed schools. As a result of the study, in areas with excellent accessibility to residents such as old downtowns and towns, libraries, entrepreneurship counseling and exhibition spaces, and lifelong education centers were desirable as part of the residents' convenience facilities. It was found that the facilities that could be used with families, such as an experiential training center, were being utilized.