• Journal of the Korean Society of Food Science and Nutrition
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• v.20 no.6
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• pp.621-628
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• 1991

Heat-stable enterotoxin(ST) from enterotoxigenic E. coli eKT-53($ST^{+}\;LT^{-}$, transformant from isolate KM-7) that was produced in succinate salts medium. The culture supernatant(crude ST) was purifed by mulitpled steps and investigated some characterization of the ST. The heatstability of purified ST activity was completely lost by treating at $100^{\circ}C$ for 30minutes. ST activity was lost by treatment at pH 1 and 12 conditions, while the activity was not reduced by treatment at pH 2~10, and then the ${\alpha}-amylase$ and pepsin was not decreased activity but disulfide reducing agnets was lost the activity. The molecular weight of the purified ST was approximately 4,200, the isoelectric point was about 4.0.

• Membrane and Water Treatment
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• v.7 no.4
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• pp.367-375
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• 2016

Although the bucky paper (BP) made from carbon nanotubes (CNTs) possesses beneficial characteristics of hydrophobic nature and high porosity for membrane distillation (MD) application, weak mechanical strength of BP has often prevented the stable operation. This study aims to fabricate the BP with high mechanical strength to improve its MD performance. The strategy was to increase the purity level of CNTs with an assumption that purer CNTs would increase the Van der Waals attraction, leading to the improvement of mechanical strength of BP. According to this study results, the purification of CNT does not necessarily enhance the mechanical strength of BP. The BP made from purer CNTs demonstrated a high flux ($142kg/m^2{\cdot}h$) even at low ${\Delta}T$ ($50^{\circ}C$ and $20^{\circ}C$) during the experiments of direct contact membrane distillation (DCMD). However, the operation was not stable because a crack quickly formed. Then, a support layer of AAO (anodic aluminum oxide) filter paper was introduced to reinforce the mechanical strength of BP. The support reinforcement was able to increase the mechanical strength, but wetting occurred. Therefore, the mixed matrix membrane (PSf-CNT) using CNTs as filler to polysulphone was fabricated. The DCMD operation with the PSf-CNT membrane was stable, although the flux was low ($6.1kg/m^2{\cdot}h$). This result suggests that the mixed matrix membrane could be more beneficial for the stable DCMD operation than the BP.

• Journal of the Korean Society of Physical Medicine
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• v.11 no.2
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• pp.33-40
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• 2016

PURPOSE: The purpose of this study was to determine the impact of stable and unstable surfaces on abdominal muscle thickness and changes in trunk muscle thickness in accordance with breathing methods during bridging exercises. METHODS: Bridging exercise on a stable surface, bridging exercise on an unstable surface, bridging exercise using a drawing-in maneuver on a stable surface, bridging exercise using a drawing-in maneuver on an unstable surface, bridging exercise using bracing on a stable surface, bridging exercise using bracing on an unstable surface. In sequence, the muscles' thickness was measured three times before and after each exercise, and the measured value was averaged. RESULTS: There were significant differences in internal oblique and transversus abdominis muscles' thickness in the drawing-in maneuver in both stable and unstable surface (p<0.05). There were no significant differences in external oblique muscle's thickness in the bridging exercise in both stable and unstable surface. The type of surface did not have a significant influence on the abdominal muscles' thickness. CONCLUSION: As a result of the study, the drawing-in maneuver had a greater effect than bridging or bracing maneuver on muscle thickness. We suggest that drawing-in maneuver will be more effective in a person with a weak abdominal muscle.

• The Journal of Korean Physical Therapy
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• v.23 no.2
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• pp.7-15
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• 2011

Purpose: We investigated the relationship between the muscle activity and kinematic variables of the upper extremity during a push-up task on stable and unstable surfaces. Methods: We recruited 15 healthy subjects. Subjects completed the push-up task on stable and unstable surfaces. Surface electromyograms were recorded from the serratus anterior, upper trapezius, latissimus dorsi, infraspinatus to monitor changes in muscle activity. Markers for kinematic changes of elbow flexion, shoulder extension, shoulder retraction and scapular adduction were attached at C7, the T7 spinous process, both acromions, the scapula superior and inferior angle, the humerus lateral epicondyle, and the ulnar styloid process. Correlation coefficients between muscle activity and kinematic variables were analyzed by SPSS for Windows, version 15.0. Results: On the unstable surface, elbow flexion and shoulder extension increased with increasing muscle activity of serratus anterior, upper trapezius and infraspinatus. On the stable surface, shoulder retraction decreased with increasing muscle activity of serratus anterior and infraspinatus. Scapular adduction decreased with all types of increasing muscle activity, regardless of the support surface. Conclusion: Correlations between muscle activity and kinematic variables were observed on stable and unstable surfaces during a push-up task, while correlations between right and left variables were not clear. These finding suggest that it may be used to develop a rehabilitation program which could be effective in improving shoulder function in patients with shoulder problems.

• Proceedings of the KIPE Conference
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• 1997.07a
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• pp.97-100
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• 1997

A new control method for the robust position control of a brushless DC(BLDC) motor using the asymptotically stable adaptive load torque observer is presented. A precision position control is obtained for the BLDC motor system approximately linearized using the field-orientation method. And the application of the load torque observer is published in [1] using fixed gain. However, the flux linkage is not exactly known for a load torque observer. Therefore, a model reference adaptive observer is considered to overcome the problem of the unknown parameter in this paper. And stability analysis is carried out using Liapunov stability theorem. As a result, asymptotically stable observer gain can be obtained without affecting the overall system response. The load disturbance detected by the asymptotically stable adaptive observer is compensated by feedforwarding the equivalent current having the fast response.

• Bulletin of the Korean Mathematical Society
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• v.50 no.4
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• pp.1201-1207
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• 2013

Let N be a complete Riemannian manifold with nonnegative Ricci curvature and let M be a complete noncompact oriented stable minimal hypersurface in N. We prove that if M has at least two ends and ${\int}_M{\mid}A{\mid}^2\;dv={\infty}$, then M admits a nonconstant harmonic function with finite Dirichlet integral, where A is the second fundamental form of M. We also show that the space of $L^2$ harmonic 1-forms on such a stable minimal hypersurface is not trivial. Our result is a generalization of one of main results in [12] because if N has nonnegative sectional curvature, then M admits no nonconstant harmonic functions with finite Dirichlet integral. And our result recovers a main theorem in [3] as a corollary.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.2271-2274
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• 2005

The desired ZMP is different from the actual ZMP of a humanoid robot during actual walking and stand upright. A humanoid robot must maintain its stable posture although external force is given to the robot. A humanoid robot can know its stability with ZMP. Actual ZMP may be moved out of the foot-print polygons by external disturbance or uneven ground surfaces. If the position of ZMP moves out of stable region, the stability can not be guaranteed. Therefore, The control of the ZMP is necessary. In this paper, ZMP control algorithm is proposed. Herein, the ZMP control uses difference between desired ZMP and actual ZMP. The proposed algorithm gives reaction moment with ankle joint when external force is supplied. 3D simulator shows motion of a humanoid robot and calculated data.

• Journal of Institute of Control, Robotics and Systems
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• v.9 no.8
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• pp.640-646
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• 2003

We presents an edge-based point correlation algorithm for fast and stable visual inspection system. Conventional algorithms based on NGC(normalized gray-level correlation) have to overcome some difficulties in applying automated inspection systems to real factory environment. First of all, NGC algorithms involve highly complex computation and thus require high performance hardware for realtime process. In addition, lighting condition in realistic factory environments is not stable and therefore intensity variation from uncontrolled lights gives many troubles for applying NGC directly as pattern matching algorithm. We propose an algorithm to solve these problems, using thinned and binarized edge data, which are obtained from the original image. A point correlation algorithm with the thinned edges is introduced with image pyramid technique to reduce the computational complexity. Matching edges instead of using original gray-level image pixels overcomes problems in NGC method and pyramid of edges also provides fast and stable processing. All proposed methods are proved by the experiments using real images.

• Journal of the Korean Physical Society
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• v.73 no.10
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• pp.1410-1419
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• 2018

A skier's motion was analyzed by a simple model consist of point mass m and a single rod connected to a single ski plate. We studied the conditions for the stable ski turn as functions of the linear velocity and the radius of the turn. The solutions for the stable ski turn in our model do not require any extra skier's movement to complete a stable circular turn. The solution may then give the skier the most comfortable skiing method without any active movement to control the ski. The generalized force supporting the point mass from the ski plate was calculated. We obtained the force from the ground (rebound force) without any geometrical structure of the ski plate. Adding an active movement to the direction of the ski plate, the conditions for the stable ski turn were also analyzed. Our result gives some insight for the skier who wants to develop technique.

• Journal of the Korea Society of Computer and Information
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• v.28 no.4
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• pp.209-216
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• 2023

In this paper, artificial intelligence agents ChatGPT and Stable Diffusion were used to explore the possibility of educational use by implementing a program to recommend picture materials for teaching and learning according to the class topic entered by teachers. The average time spent recommending all picture materials is about 6 minutes. In general, pictures related to keywords were recommended, and the letters in the recommended pictures could only know the intention to represent the letters, and the letters could not be recognized and the meaning could not be known. However, further research seems to be needed on the fact that the type or content of the recommended picture depends entirely on the response of ChatGPT and that it is not possible to accurately recommend the picture for all keywords. In addition, it was concluded that it is true that the recommended picture is related to the keyword, but the evaluation of whether it has educational value is the subject of discussion that should be left to the judgment of human teachers.