• Journal of the Korean Society for Precision Engineering
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• 제21권11호
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• pp.209-218
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• 2004

The purpose of this paper is to suggest a practical and simple method for the identification of the joint mechanical properties and to apply it to human knee joints. The passive moment at a joint was modeled by three mechanical parts, that is, a gravity term, a linear damper term and a nonlinear spring term. Passive pendulum tests were performed in 5 fat and 5 thin men. The data of pendulum test were used to identify the mechanical properties of joints through sequential quadratic programming (SQP) with random initial values. The identification was successful where the normalized root-mean-squared (RMS) errors between the simulated and experimental joint angle trajectories were less than 10％. The parameter values of mechanical properties obtained in this study agreed with literature. The inertia, gravity and the damping constant were greater at fat men, which indicates more resistance to body movement and more energy consumption fer fat men. The suggested method is noninvasive and requires simple setup and short measurement time. It is expected to be useful in the evaluation of joint pathologies.

• Fire Science and Engineering
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• 제22권4호
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• pp.33-41
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• 2008

Presently, there is no legal regulation pertaining to the installation, maintenance, management and operation of fire-fighting facilities in single housing in Korea, relying instead on the awareness of the residents which hopefully will prevent fire. Likewise, accident prevention effort is very limiting and weak. Accordingly, this research examines current situation in which fire results, identifies root causes and studies application of regulations and develop design measures centered on the single housing that is most afflicted with fire. As part of the measure to prevent fire that afflict housing, it is necessary to classify single housing as specific target for fire fighting just like the joint housing among the types of the building structures that are classified according to the usage on the "Appendix Chart I of the Enforcement Ordinance of the Construction Law" for management purpose. Moreover, it is necessary to make the installation of fire-fighting facilities such as simple sprinkler facility for residential area, fire extinguisher, warning system and others for the sake of the senior citizens and disabled people who reside in single housing, mandatory.

• Geomechanics and Engineering
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• 제34권6호
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• pp.697-726
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• 2023

Brittleness as an important property of rock plays a crucial role both in the failure process of intact rock and rock mass response to excavation in engineering geological and geotechnical projects. Generally, rock brittleness indices are calculated from the mechanical properties of rocks such as uniaxial compressive strength, tensile strength and modulus of elasticity. These properties are generally determined from complicated, expensive and time-consuming tests in laboratory. For this reason, in the present research, an attempt has been made to predict the rock brittleness indices from simple, inexpensive, and quick laboratory test results namely dry unit weight, porosity, slake-durability index, P-wave velocity, Schmidt rebound hardness, and point load strength index using multiple linear regression, exponential regression, support vector machine (SVM) with various kernels, generating fuzzy inference system, and regression tree ensemble (RTE) with boosting framework. So, this could be considered as an innovation for the present research. For this purpose, the number of 39 rock samples including five igneous, twenty-six sedimentary, and eight metamorphic were collected from different regions of Iran. Mineralogical, physical and mechanical properties as well as five well known rock brittleness indices (i.e., B₁, B₂, B₃, B₄, and B₅) were measured for the selected rock samples before application of the above-mentioned machine learning techniques. The performance of the developed models was evaluated based on several statistical metrics such as mean square error, relative absolute error, root relative absolute error, determination coefficients, variance account for, mean absolute percentage error and standard deviation of the error. The comparison of the obtained results revealed that among the studied methods, SVM is the most suitable one for predicting B₁, B₂ and B₅, while RTE predicts B₃ and B₄ better than other methods.

• KOREAN JOURNAL OF CROP SCIENCE
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• 제56권1호
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• pp.72-79
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• 2011

Here we report a simple screening system using hematoxylin staining (HS) of the root apex. It allowed rapid classification into different aluminum (Al) tolerance from 65 cultivars within one week. Using this system, we selected the most Al-tolerant (Jayae-2) and-sensitive (Pum-2) barley (Hordeum vulgare L.) The results show that the different responses in Al-induced growth inhibition, Al accumulation and expression of plasma membrane (PM) $H^+$-ATPase in root apices of selected two cultivars. It showed strongly Al-induced growth inhibition in a dosedependant manner only in Pum-2 but not in Jayae-2. Aluminum accumulation in root apices (10 mm) was significantly higher in Pum-2 only. The $H^+$-ATPase expression of PM vesicles by western blotting was decreased in Pum-2 but not in Jayae-2 treated with $20{\mu}M$ Al for 24 h. These finding indicate to screen from our system is rapid and reliable and to sustain the expression of PM $H^+$-ATPase at translational level is an important role in root growth as affected by Al.

• The Journal of the Korean dental association
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• 제15권6호
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• pp.437-443
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• 1977

Author came to the following conclusion and made the following report as a result of corticotomy that treated in department of orthodontics and oral surgery, Tokyo Dental College. 1. In the respect of oral surgery, corticotomy is able to operate under local anesthesia. This operation is very simple and there is little clinical discomfort after operation. 2. In the respect of orthodontics, tooth movement is 2-3 times rapid than common orthodontic treatment in adult and clinical problem such as pain, root resorption are slight. Especially, tooth movement by differential force, rapid expansion in adult and unilateral expansion which was difficult, came to possible. 3. Corticotomy shorten the treatment time in preoperative orthodontic treatment of developmental abnormality of jaw, application to cleft lip & palate, orthodontic treatment before prosthetics. It's application is so wide that bring on much profits.

• Proceedings of the KSME Conference
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• 대한기계학회 2001년도 춘계학술대회논문집E
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• pp.185-190
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• 2001

Rotating disks are used in various machines such as floppy disks, hard disk, turbines and circular sawblades. The problems of vibrations of rotating disks are important in improving these machines. Many investigators have dealt with these problem. Specially, vibrations of a rotating flexible disk taking into account the effect of air is difficult problem in simulation. The governing equation of a rotating flexible disk coupled to the surrounding fluid is investigated by a simple mathematical model. And several important parameters concerned with the stability of a rotating flexible disk are defined. Coupling strength between air and rotating flexible disk is proportional to square of disk radius directly and square root of the all of bending rigidity, disk density and thickness inversely. Lift-to-damping coefficient has relation to the onset of disk flutter.

• Journal of the Korean Society for Precision Engineering
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• 제21권12호
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• pp.75-83
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• 2004

With the rotating machinery getting more accurate and diversified, the necessity fur an appropriate diagnosis technique and maintenance system has been greatly recognized. However, until now, the operator has executed a monitoring of the machine by the senses or simple the change of RMS (root mean Square) value. So, the diagnostic expert system using the fuzzy inference which the operator can judge easily and expertly a condition of the machine is developed through this study. In this paper, the hardware and software of the diagnostic expert system was composed and the identification of the diagnostic performance of the developed system for 5 fault phenomena was carried out.

• Journal of KSNVE
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• 제1권2호
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• pp.129-140
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• 1991

The boiler feed pump located at a power plant has been experienced a severe vibration since the plant began to service in early 1980. The research is focused on the field measurement and implementation of simple signal processing techniques in order to provide realistic and effective solution which could be implemented into the plant. Based on the root cause analysis for the trouble-making pump system, the driving part gear in the fluid coupling system is identified as a potential source. The followed verification test confirms the analytical result. The test result shows that vibration reduction obtained after the gear replacement reaches up 15.8 dB, which is 1/6 times of the vibration level compared to that of the troble-making pump. The measured vibration level of the pump satisfies the manufacture criteria and guarantees the smoothed operation.

• Journal of Applied Biological Chemistry
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• 제58권4호
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• pp.377-381
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• 2015

The content analysis of 6-gingerol, which is an active compound, in Zingiber spp. (Z. officinale and Z. mioga) and their commercial foods (ginger teas and powders) was conducted using high-performance liquid chromatography. A reverse phase system was used, with a gradient solvent system of water and acetonitrile. The 6-gingerol content was highest in the methanol extract of Z. officinale root (17.09 mg/g extract) and ginger powder B (15.92 mg/g extract). The results demonstrated that this method was simple and reliable for the quality control of Zingiber commercial foods.

• Transactions of the Korean Society of Automotive Engineers
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• 제15권5호
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• pp.48-55
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• 2007

A bushing component of a vehicle suspension system is tested to capture the nonlinear behavior of rubber bushing element using the MTS 3-axes rubber test machine. The results of the tests are used to model the artificial neural network bushing model. The performances from the neural network model usually are dependent on the structure of the neural network. In this paper, maximum error, peak error, root mean square error, and error-to-signal ratio are employed to evaluate the performances of the neural network bushing model. A simple simulation is carried out to show the usefulness of the developed procedure.