• The Journal of Korea Robotics Society
• /
• v.1 no.2
• /
• pp.135-141
• /
• 2006

This paper presents offline estimation of equivalent physical damping parameter in haptic interaction systems where damping is the most important parameter for stability. Based on the previous energy bounding algorithm, an offline procedure is developed in order to estimate the physical damping parameter of a haptic device by measuring energy flow-in to the haptic device. The proposed method does not use force/torque sensor at the handgrip. Numerical simulation and experiments verified effectiveness of the proposed method.

• Physical Therapy Korea
• /
• v.5 no.1
• /
• pp.1-16
• /
• 1998

This study analysed national data of manpower supply for physical therapists in Korea. Based on the comparative analysis results of the future demand and supply, as of May 1998, it is estimated that there was already an oversupply of physical therapists in Korea. This oversupply is expected to continue even though there would be an increase in hospital beds, rehabilitation facilities for the elderly, and nursing homes. Thus it would be desirable to cut down the number of students admitted to physical therapy schools each year. Our estimation shows that the Ministry of Health and Welfare must take measures to reduce the supply of physical therapist as soon as possible.

• 제어로봇시스템학회:학술대회논문집
• /
• 2000.10a
• /
• pp.526-526
• /
• 2000

The present has a double objective. The first one is to compare and estimate sixteen continuous-time methods through the identificatiun of a system consisted with an RLC electrical circuit. These sixteen methods are classified into three groups that are the linear filters, the modulating functions and the integral methods. The second objective is to estimate directly the physical parameters of the RLC circuit, without resorting to a discrete-time model. The system is consisted of a coil with inductance L and resistance H, and of a capacitor with capacitance C. Having written the physical equations which describe the behavior of the system, the transfer function in where the initial conditions appear is given. These initial conditions should be taken into account during the parameter estimation phase, because they are inevitable within the framework of real signals. A physical interpretation of the identified models is tempted by the direct estimation of the physical parameters L and C. In conclusion, a classification of the studied methods is proposed.

• Journal of the Korean Mathematical Society
• /
• v.58 no.3
• /
• pp.723-740
• /
• 2021

Design and maintenance of large span roof structures require an analysis of their static and dynamic behavior depending on the physical parameters defining the structures. Therefore, it is highly desirable to estimate the parameters from observations of the system. In this paper we study the parameter estimation problem for damped shallow arches. We discuss both symmetric and non-symmetric shapes and loads, and provide theoretical and numerical studies of the model behavior. Our study of the behavior of such structures shows that it is greatly affected by the existence of critical parameters. A small change in such parameters causes a significant change in the model behavior. The presence of the critical parameters makes it challenging to obtain good estimation. We overcome this difficulty by presenting the Parameter Estimation Algorithm that identifies the unknown parameters sequentially. It is shown numerically that the algorithm achieves a successful parameter estimation for models defined by arbitrary parameters, including the critical ones.

• Geomechanics and Engineering
• /
• v.15 no.1
• /
• pp.631-643
• /
• 2018

The estimation of the strength and other mechanical parameters characterizing the tensile behavior of granites can play an important role in civil engineering tasks such as design, construction, rehabilitation and repair of existing structures. The purpose of this paper is to apply data mining techniques, such as multiple regression (MR), artificial neural networks (ANN) and support vector machines (SVM) to estimate the mechanical properties of granites. In a first phase, the mechanical parameters defining the complete tensile behavior are estimated based on the tensile strength. In a second phase, the estimation of the mechanical properties is carried out from different combination of the physical properties (ultrasonic pulse velocity, porosity and density). It was observed that the estimation of the mechanical properties can be optimized by combining different physical properties. Besides, it was seen that artificial neural networks and support vector machines performed better than multiple regression model.

• Journal of the Ergonomics Society of Korea
• /
• v.6 no.1
• /
• pp.3-8
• /
• 1987

This paper develops a statistical mode which estimates mental and physical loads of light work from sinus arrhythmia (SA) scores. During experiments, various levels of mental and physical loads (respectively scored by information processing and finger tapping rates) were imposed on subjects and SA scores were measured from the subjects. Two methods were used in developing workload estimation model. One is an algebraic inverse function of a multivariate regression equation, where mental and physical loads are independent variables and SA scores are dependent variables. The other is a statistical multivariate inverse regression. Of the two methods, inverse function resulted in larger mean squqre error in predicting mental and physical loads. Hence, inverse regression model is recommended for precise workload estimation.

• The Journal of Korean Physical Therapy
• /
• v.19 no.1
• /
• pp.23-31
• /
• 2007

Purpose: As a preliminary study, the purpose of this study was to examine the indirect estimation of the lumbar intervertebral disc size by two anthropometric methods, in order to compare these indirect methods with the direct analysis by radiological imaging. Methods: The wrist, elbow, knee, and ankle joint (both right and left) diameters were measured in 52 volunteers, and then intervertebral disc size was calculated using two anthropometric methods (Colombini and modified Colombini). The data were analysed with independent t-test to assess clinical usefulness. Results: When using right and left joint diameter, there was no significant difference in the estimation value of the L4-5 and L5-S1 intervetebral disc sizes. However, the study has shown that male subjects have significantly larger L4-5 and L5-S1 intervertebral disc sizes, compared with those of female subjects. In addition, disc sizes calculated by Colombini's formula were significantly larger than modified Colombini's formula. Conclusion: The indirect estimation of the intervertebral disc size by anthropometric method can be considered as a clinically useful method. However, further study should be conducted to compare anthropometric values with other radiological imaging.

• Proceedings of the Korea Concrete Institute Conference
• /
• 1999.10a
• /
• pp.183-186
• /
• 1999

Up to date, it is difficult to estimate the consistence of properties on the epoxy liner in service time because an estimation of the long term environment-deterioration with aging has not been processed. In the study, the estimation on epoxy liner is carried by the physical test 7 rounds. There are the elongation the and the crack bridging test in the part of physical tests. An elongation test is carried out with epoxy membrane and a crack bridging test is carried out with specimen painted epoxy on concrete. The subjects of test and estimation are a containment quality system and a fibre-glass reinforced system. The materials of these systems are a Robber added Epoxy, a Silica added Epoxy, and a Fiber reinforced Epoxy. Ensuring the test data, properties of epoxy liner was estimated and the change of properties was predicted on epoxy liners.

• Journal of the Korean Society for Precision Engineering
• /
• v.28 no.6
• /
• pp.663-669
• /
• 2011

This paper examines methods to estimate torque and angle in shoulder flexion from surface electromyography(sEMG) signals for intuitive and delicate control of robotic assistance device. Five muscles on the upper arm, three for shoulder flexion and two for shoulder extension, were used to offer favorable sEMG recording conditions in the estimation. The methods tested were the mean absolute value (MAV) with linear regression and the artificial neural network (ANN) method. An optimal condition was sought by varying combination of muscles used and the parameters in each method. The estimation performance was evaluated using the correlation values and normalized root mean square error values. In addition, we discussed their possible use as an estimation of motion intent of a user or as a command input in a physical human-machine interaction system.

• Communications for Statistical Applications and Methods
• /
• v.23 no.2
• /
• pp.147-161
• /
• 2016

This paper introduces the four parameter new generalized inverse Weibull distribution and investigates the potential usefulness of this model with application to reliability data from engineering studies. The new extended model has upside-down hazard rate function and provides an alternative to existing lifetime distributions. Various structural properties of the new distribution are derived that include explicit expressions for the moments, moment generating function, quantile function and the moments of order statistics. The estimation of model parameters are performed by the method of maximum likelihood and evaluate the performance of maximum likelihood estimation using simulation.