• Journal of Institute of Control, Robotics and Systems
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• v.15 no.10
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• pp.1062-1070
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• 2009

The strip shape for the stainless steel process has made an issue of the strip quality, and hence the shape control method is developed at the Sendzimir rolling mill (ZRM). ZRM is a stainless cold rolling mill and has actuators for the shape control. They are first intermediate rolls and top crown rolls, which are controlled horizontally and vertically, respectively. The shape control of the stainless steel rolling process has difficulty in obtaining the symmetrical shape. The objective of the shape control is to minimize the shape deviation and to maintain stable state, which keeps symmetrical shape pattern in the lateral direction. The method of the shape recognition employs a least squares method and neural network. The shape deviation is the difference between the target shape and actual shape and is controlled by the fuzzy shape control. The fuzzy shape control using operator's informative knowledge is proposed in this paper. The experiments are carried out online for various stainless materials and sizes. The productivity of the rolling process has increased from 9.0 to 9.4 tons per hour.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.15 no.2
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• pp.367-377
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• 2002

This paper deals with the free vibrations of shallow arches resting on elastic foundations. Foundations we assumed to follow the hypothesis proposed by Pasternak. The governing differential equation is derived for the in-plane free vibration of linearly elastic arches of uniform stiffness and constant mass per unit length. Two arch shapes with hinged-hinged and clamped-clamped end constraints we considered in analysis. The frequency equations (lowest symmetrical and antisymmetrical frequency equations) we obtained by Galerkin's method. The effects of arch rise, Winkler foundation parameter and shear foundation parameter on the lowest two natural frequencies are investigated. The effect of initial arch shapes on frequencies is also studied.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.16 no.1 s.92
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• pp.78-83
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• 2005

LTCC filters have been widely used to wireless terminals. They generally adopt the multilayer structure. Some of multilayer LTCC filters are made of symmetrical parallel-coupled lines and anti-symmetrical parallel-coupled lines to reduce the length of resonators. The equivalent circuit of parallel-coupled lines was analyzed and applied to bandpass filters using multilayer parallel-coupled line resonators. The three-pole bandpass filter with the center frequency of 2.45 GHz is designed by using the proposed equivalent circuit and the measured results have good agreement with the design results.

• Journal of Advanced Marine Engineering and Technology
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• v.12 no.2
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• pp.46-56
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• 1988

The author has presented a new approach to design hydrofoil section shapes in consideration of viscous for marine propeller blades. In suction sides of propeller blades, the pressure distribution on hydrofoil sections in non-cavitating flow should be examined before the study of cavitation characteristics. Generally, the calculation results for hydrofoil conformal mapping method by which neglect viscous effects do not agree with experimental ones. Moreover, another papers reported that laminar separation bubble and transition played an important role on the cavitation inception. From these considerations, it is very important to study the viscous effects of the hydrofoil sections, especially the mechanism separation bubble and the apparent thickness of hydrofoil section. Therefore, the new design method of hydrofoil sections in consideration of viscous effects in comparison to the airfoil section should be studied. In designing the new hydrofoil section shapes, based on Eppler theory, the author tried to give the peak negative pressure in leading edge region for NACA airfoil in consideration of viscous effects without turbulent boundary layer separation as much as possible. The design method was verified from the fact that the boundary characteristics was improved and the lifts of new hydrofoils were slightly in creased in comparison to these of NACA 16-012 symmetrical, NACA 4412 non-symmetrical airfoils.

• Journal of the Korean Institute of Telematics and Electronics T
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• v.36T no.2
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• pp.63-69
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• 1999

The frequency-dependent characteristics of the finline have previously been analyzed using several frequency domain approaches. But the time domain TLM method presented in this paper is another independent approaches for obtaining frequency domain results for finline. The structure analysed with this algorithm is unilateral finline in WR-62 waveguide enclosures and the symmetrical condensed node based on the properties of Huygen's scattering model is used. From the TLM results, the frequency-dependent scattering parameters of a unilateral finline have been calculated by Fourier transform of the time domain data. The numerical results are in good agreements with other paper, thus demonstrating the validity and usefulness of the proposed method.

• Wind and Structures
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• v.25 no.6
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• pp.551-567
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• 2017

Studies of unsymmetrical blade H-Darrieus rotors at low wind speeds in terms of starting time, static torque, and power performances for different blade parameters: thickness-to-chord (t/c), camber position, and solidity are scarce. However these are required for knowing insights of rotor performances to obtain some design guidelines for the selection of these rotors. Here, an attempt is made to quantify the effects of these blade parameters on the performances of three different H-Darrieus rotors at various low wind streams. Different blade profiles, namely S815, EN0005 (both unsymmetrical), and NACA 0018 (symmetrical blade for comparison) are considered. The rotors are investigated rigorously in a centrifugal blower apparatus. Firstly the dynamic and static performances of the rotors are evaluated to determine the best performing rotor and their optimum solidity. Generalised performance equations are developed based on selected blade parameters which are validated for the unsymmetrical rotors. Further, the starting time is quantified with respect to the rotor inertia to determine the suitable range of inertia that helps the unsymmetrical blade rotor to self-start earlier than the symmetrical one. This study can work as a benchmark for the selection of optimum blade parameters while designing an unsymmetrical blade rotor at low wind speeds.

• The Journal of Korean Physical Therapy
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• v.23 no.3
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• pp.43-47
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• 2011

Purpose: This study determined the best adjustable height supporter for stroke patients in wheelchairs for the maintenance of a symmetric sitting posture. Methods: Thirty-one stroke participants and 20 age-matched control participants were recruited. The enrolled participants were evaluated by the Force Sensitive Application (FSA) System that was used to assess weight shift and symmetry in wheelchair sitting and assess the symmetric index (SI) of subjects according to 1, 2 and 3 cm height supporters. Results: When a 1 cm height supporter was applied to the paretic side of stroke survivors, sitting postures of stroke patients were significantly more symmetrical (p<0.01). Cross tabulation between the SI of wheelchair sitting and that of the paretic side of stroke patients caused? by a 1 cm supporter showed that 21 SIs of 26 stroke patients were improved by a 1 cm supporter to the paretic side (k=0.26, p<0.01). Conclusion: The findings of the present study demonstrate that stroke patients can maintain a more symmetrical sitting posture (than is possible when simply sitting in a wheelchair seat) if a 1 cm supporter is applied to the paretic side of stroke patients.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.1 no.1
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• pp.5-11
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• 1971

The author has observed the orthopantomograms of the maxillary sinus which were taken by special exposure method to study mesiodistal dimension, shape, symmetrical relationship, bony septum of the maxillary sinus and relationship between upper. 1st molar and the maxillary sinus, that were selected 56 cases of 23 to 27 years old male, who have good. systemic conditions and no missing teeth on upper posterior molar in normal occlusion, and obtained following conclusions: 1. Mesiodistal dimensions of the maxillary sinus are shown as follows; The mean of left dimension is 50.94±8.34㎜ and of right dimension is 49.50±9.87㎜. 2. To the shape of the maxillary sinus, V or U shape are 33cases(29.5%) and W shape are 77 cases(70.5%). 3. In the ralationship between upper 1st molar and floor of the maxllary sinus, superimposition are 62 cases (55.36%) and aproach are 50 cases (44.64%). 4. In the right and left symmetrical relationship of the maxillary sinus, symmetry are 37cases (66.07%) and asymmetry are 19 cases (33.93%). 5. The bony septums in the maxillary sinuses revealed that presence of bony septums are 29 cases (25.8%) and absence are 83 cases (74.11%).

• Physical Therapy Korea
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• v.12 no.1
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• pp.91-99
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• 2005

We assessed whether the use of a symmetrical upper limb motion trainer in daily repetitive training for a 6-week period reduced spasticity and improved motor function in three chronic hemiparetic patients. Upper limb motor impairment and disability were measured by the Fugl-Meyer Assessment (FMA), Modified Ashworth Scale (MAS) and Manual Muscle Test (MMT), respectively. The electromyography (EMG) of the affected hand was recorded during isometric wrist flexion and extension. In all patients, FMA and MMT scores were significantly improved after the 6-week training. However, MAS scores of the affected wrist spasticity did not change considerably. Onset and Offset delays in muscle contraction significantly decreased in the affected wrist. The co-contraction ratio of flexor and extensor muscles significantly increased after the 6-week training. Onset and offset delays of the muscle contraction and co-contraction ratio correlated significantly with the patients' FMA. This study showed that repetitive, symmetric movement training can improve upper limb motor functions and abilities in chronic hemiparetic patients. Also, the EMG assessment of motor response is likely to provide insights into mechanisms and treatment strategies for motor recovery in chronic hemiparetic patients.

• Journal of Aerospace System Engineering
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• v.8 no.2
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• pp.7-13
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• 2014

In order to enable fail-safe operation the electro-hydrostatic actuators can be dualized. When a symmetrical actuator is combined in series with an asymmetrical actuator with single rod cylinder, the flow rates of their cylinders are unmatched. If their position controller has same configuration, one of their pumps can supply too much flow rate under particular load conditions, which should be bypassed into low pressure side e.g. by a relief valve. In this paper it is shown how the hydraulic circuit for the asymmetrically combined electro-hydrostatic actuator can be designed without sacrificing power consumption.