• 제어로봇시스템학회:학술대회논문집
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• 1991.10a
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• pp.299-304
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• 1991

A novel approach based on a nonlinear compensator is proposed to prevent 'windup', which is caused by the saturation of the actuator and the integration action of the controller. The anti-windup compensator is located between the conventional linear controller, designed neglecting the saturation, and the actuator. It was proven based on the describing function method that, if the closed loop control systems are stable assuming no saturation, then there exist a range of compensator gain which prevents any limit-cycle and hence, guarantees the system stability. The computer simulation results show that the compensator proposed in the manuscript can eliminate unstable limit cycle and improve the transient response.

• Steel and Composite Structures
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• v.34 no.3
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• pp.321-332
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• 2020

The loss of composite action at the hogging moment zone for a continuous composite girder reduces the girder stiffness and strength. This paper presents an experimental investigation of the use of an ultra-high performance concrete (UHPC) slab at the hogging moment zone and a normal concrete (NC) slab at the sagging moment zone. The testing was conducted to verify the level of loading at which composite action is maintained at the hogging moment zone. Four two-span continuous composite girders were tested. The thickness of the UHPC varied between a half and a full depth of slab. The degree of shear connection at the hogging moment zone varied between full and partial. The experimental results confirmed the effectiveness of the UHPC slab to enhance the girder stiffness and maintain the composite action at the hogging moment zone at a load level much higher than the upper service load limit. To a lesser degree enhanced performance was also noted for the smaller thickness of the UHPC slab and partial shear connection at the hogging moment zone. Plastic analysis was conducted to evaluate the ultimate capacity of the girder which yielded a conservative estimation. Finite element (FE) modeling evaluated the girder performance numerically and yielded satisfactory results. The results indicated that composite action at the hogging moment zone is maintained for the degree of shear connection taken as 50% of the full composite action and use of UHPC as half depth of slab thickness.

• The Journal of Korean Physical Therapy
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• v.32 no.6
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• pp.365-371
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• 2020

Objective: To investigate the action observation effects of functional electrical stimulation (FES) on the communication between motor cortex and muscle through corticomuscular coherence (CMC) analysis. Methods: Electroencephalogram (EEG) and electromyogram (EMG) of 27 healthy, nonathlete subjects were measured during action observation, FES, and action observation with FES, which lasted for 7sper session for 10 times. All trials were repeated for 30 times. Simultaneously measured EEG raw data and rectified EMG signals were used to calculate CMC. Only confidence limit values above 0.0306 were used for analysis. CMC was divided into three frequency domains, andthe grand average coherence and peak coherence were computed. Repeated ANOVA was performed to analyze the coherence value difference for each condition's frequency band. Results: CMC showed significant differences in peak coherence and average coherence between the conditions (p<0.05). Action observation application with FES in all frequency band showed the highest peak and average coherence value. Conclusions: The results of this study are assumed to be the combination of increased eccentric information transfer from the sensorymotor cortex by action observation and an increased in concentric sensory input from the peripheral by the FES, suggesting that these are reflecting the sensorimotor integration process.

• Earthquakes and Structures
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• v.18 no.3
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• pp.367-377
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• 2020

Incremental dynamic analysis (IDA) widely uses for the collapse risk assessment procedures of buildings. In this study, an IDA-based collapse risk assessment methodology is proposed, which employs a novel approach for detecting the near-collapse (NC) limit state. The proposed approach uses the modal pushover analysis results to calculate the maximum inter-story drift ratio of the structure. This value, which is used as the upper-bound limit in the IDA process, depends on the structural characteristics and global seismic responses of the structure. In this paper, steel midrise intermediate moment resisting frames (IMRFs) have selected as case studies, and their collapse risk parameters are evaluated by the suggested methodology. The composite action of a concrete floor slab and steel beams, and the interaction between the infill walls and the frames could change the collapse mechanism of the structure. In this study, the influences of the metal deck floor and autoclaved aerated concrete (AAC) masonry infill walls with uniform distribution are investigated on the seismic collapse risk of the IMRFs using the proposed methodology. The results demonstrate that the suggested modified IDA method can accurately discover the near-collapse limit state. Also, this method leads to much fewer steps and lower calculation costs rather than the current IDA method. Moreover, the results show that the concrete slab and the AAC infill walls can change the collapse parameters of the structure and should be considered in the analytical modeling and the collapse assessment process of the steel mid-rise intermediate moment resisting frames.

• Magazine of the Korea Concrete Institute
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• v.4 no.4
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• pp.135-147
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• 1992

본 연구는 기존의 이론을 배경으로 전단키에 영향을 미치는 전달전달의 요소가 포함된 기본식을 산정하여, 접합부의 유형에 따라 구체적으로 전단강도를 예측하는 방법을 제안하였다. 접합부 콘크리트와 횡보강철근의 강도 및 장부호과를 고려한 프리캐스트 콘크리트 전단키 접합부의 기본극한강도식은 수정 Mohor-Coulomb의 파괴기준과 항복선의 도입에 의하여 전개하였고, 극한전단능력의 근사해는 상하계법에 의한 극치해석의 수법을 이용하여 구하고 여기에 재료의 유효강도계수를 도입하였다. 또한, 지존의 실험결과와 비교하여 그 적용성을 고찰하였다.

• Journal of Korean Society for Quality Management
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• v.40 no.4
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• pp.467-480
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• 2012

Purpose: This paper introduces new 2-of-3 main and supplementary runs rules to increase the performance of the classical $\bar{X}$ control chart for detecting small process shifts. Methods: The proposed runs rules are compared with other competitive runs rules by numerical experiments. Nonlinear optimization problem to minimize the out-of-control ARL at a specified shift of process mean for determining action and warning limits at a time is formulated and a procedure to find two limits is illustrated with a numerical example. Results: The proposed 2-of-3 main and supplementary runs rules demonstrate an improved performance over other runs rules in detecting a sudden shift of process mean by simultaneous changes of mean and standard deviation. Conclusion: To increase the performance in the detection of small to moderate shifts, the proposed runs rules will be used with $\bar{X}$ control charts.

• Earthquakes and Structures
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• v.23 no.4
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• pp.339-352
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• 2022

Due to the large volume and generally as a public building, the damage of large-span space structures under various non-conventional loads will cause greater economic losses, casualties, and social impacts, etc. Therefore, it is particularly important to evaluate the seismic performance of large-span space structures. This paper taked a multipurpose sports center as an example and considered its synergistic deformation based on the method of equivalent damping ratio. Furthermore, The ABAQUS software was used to analyze the time-history and energy response of the multipurpose sports center under the action of rare earthquakes, and proposed a quantitative damage index to assess the overall damage of the structure. Finally, the research results indicated that the maximum inter-story drift ratio of the multipurpose sports center under the action of rare earthquakes was less than its limit value. The frame beams presented different degrees of damage, but the key members were basically in an elastic state. The bearing capacity did not reach the limit value, which satisfied the intended seismic performance target. This study taked an actual case as an example and proposed a relevant damage evaluation system, which provided some reference for the analysis of the seismic performance of large-span space structures.

• The Korean Journal of Physiology
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• v.23 no.2
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• pp.339-350
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• 1989

Electrophysiological effects of ammonia was studied in the isolated superfused sinus node and atrial muscle cells of the rabbit heart. No significant changes were observed in the overshoot potential (05), maximum diastolic potential (MDP), and action potential amplitude (APA) of the sinus node cells following superfusion with 3.0 mM ammonia, fifty times upper limit of the normal human plasma level. However the action potential duration (APD) of sinus node cells were significantly prolonged after superfusion with 0.6 mM ammonia for 20 min or with 1.2 and 3.0 mM ammonia for 5 minutes. Ammonia in all the concentrations tested decreased the rate of spontaneous firing (RSF) from the sinus node cells. After superfusion of sinus node cells with 0.3 mM ammonia for 20 min, the RSF significantly decreased from 20 min to 25 min after onset of superfusion while a significant decrement in the RSF was observed from 7 min to 30 min following superfusion with 3.0 mM ammonia for S min. On the other hand, the effects of ammonia on the action potential of the rabbit atrial muscle cell were much similar to those on pacemaker cells except that the atrial cell was generally less sensitive to ammonia. The results suggest that ammonia may cause changes in the action potential of the rabbit cardiac cells by the direct action, and that the cardiac effects of ammonia are generally opposite to those of glycine.

• Journal of Digital Convergence
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• v.12 no.1
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• pp.13-21
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• 2014

The problem of the cases of Soribada and Winny is their duplexity that they could be used legally and illegally. The issue called 'The crime of aiding through the neutral behavior' is about whether the program developer who shared the file sharing program letting unspecified public infringe the copyright could be punished or not. Many theories about limiting the traditional scope of punishment of aider have been maintained. However, it is questionable whether it is possible to limit the scope of punishment following the former cases and theories even for the action that is causal and facilitates the principal's criminal conduct, like the aid through the neutral action which is hard to perceive as illegal aid because of its characteristics. Therefore, using the case of Soribada in Korea and the case of Winny in Japan as the examples of illegal aid through neutral behavior case, this paper examines the characteristics and problems of aid through existing theories and cases, and suggests new scope of punishment limitation standard through the elaboration of the action of aid and judgment of degree.

• Journal of the Korean Institute of Navigation
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• v.1 no.1
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• pp.27-44
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• 1977

The Maneuvering Indices of a ship are the values that decide the quantity of her motion in turning when her rudder is turned over to an angle to the starboard or the port. They consist of two kinds of indices, one of which is called index K and the other, index T. Index K decides a ship's turning ability and index T does the length of time delay of a normal turning motion after her rudder has finished the turn of an ordered angle. Generally, the values of the indices are calculated through some mathematic formulas with figures of her heading degrees recorded at a fixed time intervals during her Z test. The values of the same kind index of a ship appear differently according to the ship'sspeed, trim, rudder angle and loaded condition, etc. In this paper, the author analyzed all the amthematic formulas required to calculate the values of the indices in their forming process and examined them from the point of mathematics and dynamics and also actually figured out the values of maneuvering indices of the M.S. "HANBADA", the training ship of Korea Merchant Marine College through her Z test. The author supposed a case in which two same typed ships as the "HANBADA" in size, shape and conditions were approaching each other in meeting end on situation and each ship turned her rudder hard over to the starboard respectively when they approached to the distance of 3 times as long as the ship's length. The author worked out mathematic formulas calculating forward and transverse ship's motions within the above mentioned situation for the quantative analysis of the collision avoding action to certify whether they are in collision status or not. Applying the calculated values of the maneuvering indices of the "HANBADA" to the motion calculating formulas, the author found out the two ships were passing over each other with the clearing distance o 39m between their port quarters. With the above mentioned examinations and explanations, the author demonstrated that a ship's motion in any collision avoiding action can be shown with quantities of time and distance within reliable limit.istance within reliable limit.