• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.8 no.4
• /
• pp.97-103
• /
• 2009

Since a demand for an extensive range of earthmoving equipment like a hydraulic excavator with a capacity of 85tons has been asked in construction fields, a performance of its track drive unit has to be verified experimentally. Among the verification of the performances, a torque measurement is at issue, in which a torque meter is utilized widely. However, the very large scaled torque meter is necessary when a discharged torque from the track drive unit is increased significantly. In addition, the price for experimental set-up of a torque meter is too high due to its limitation of the geometry such as long length, and a break down in operation occurs frequently. In this study, to measure a high torque up to 200,000Nm, a new technique was proposed as an alternative of conventional measurement by using a torque meter. The new technique enables to measure the high torque stably in a compact space via a torque arm and two load cells. The experimental results showed a propriety of the proposed torque measuring technique for a track drive unit with very large capacity.

• Journal of the Korean Society of Environmental Restoration Technology
• /
• v.16 no.6
• /
• pp.119-133
• /
• 2013

The purpose of this study is to develop riverbed techniques to activating ecological function of hyporheic zone. Hyporheic zone maybe simply defined as an active eco-tone between surface water and groundwater, which facilitates to exchange water, nutrients and aquatic habitat occur in response to variation in discharge and bed geomorphology. The aim of this study is to evaluate the effectiveness of an applied riverbed technique for two years since its installation in the hyporheic zone. The experimental riverbed technique has been implemented on Anyang stream penetrating Anyang city in Gyunggi province. The dimension of the installed structure is 5.0 m in width, 46 m in length. Bottom layer is filled with rip-rap covered with gabion. After the implementation of the technique, the study conducts follow-up monitoring in two years of between 2011 and 2012. The results of follow-up monitoring for two years are as follows:1) In Hydro geomorphic process, the riverbed technique maintains hydraulic stability despite of several flood events in 2011, 2012. 2) After transformation to form pool-and-riffle habitat, for aquatic community composed of freshwater fish, macro invertebrate, and attached algae, the species diversity and population gradually increased. 3) The riverbed technique achieved desired effect on enhancement of ecological function in hyporheic zone.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
• /
• v.28 no.2
• /
• pp.25-34
• /
• 2022

Background: Cervical headache (CGH) is a common condition that causes serious damage. Mulligan described a sustained natural apophyseal glides (SNAGs) as a manual therapy approach to treat this dysfunction. Although there have been several case studies to evaluate the effectiveness of SNAG, the efficacy of SNAG for cervical headaches is still controversial. Therefore, this study examined the effects of Mulligan's SNAG technique on cervical headache and pain intensity to present basic clinical data. Methods: Thirty-two subjects participated in this study, 16 each in the experimental and control groups. The experimental group applied Mulligan's SNAGs technique and the control group applied the placebo SNAGs technique. Results: Significant differences (p<.05) in the changes in pain, neck disability index (NDI) and Hamilton rating scale for depression (HRSD) were observed between the two groups. Conclusion: The application of Mulligan's SNAG technique to patients with cervical headaches effectively reduced headache, depression, and neck dysfunction. Based on this study, Mulligan's SNAGs technique can be used as an objective research method for additional studies targeting cervical headache patients in the future.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.34 no.2
• /
• pp.415-424
• /
• 2014

The carrying capacity of existing concrete structures is evaluated by the measured data from displacement and strain gauges for given loads and the results of numerical analysis that are compared with the measured ones. Consequently, this process could be accomplished in doing the direct measurement of residual stress on existing concrete. This study is concerned with the development of IITC (Instrumented Indentation Technique for Concrete) system which is based on the experimental stress analysis technique using non-destructive test method to evaluate the residual stress of concrete structures depending on the types of applied loadings in analysing indentation load - indentation depth curve derived experimentally on concrete surface. As a result, in this paper, almost all of systematized H/W and S/W were newly developed to estimate the residual stresses of concrete structures. Thus, the creation of new experimental equations for deriving residual stresses and automatical calculations of residual stresses using the empirical formula can lead to evaluate the structural resistances conveniently in the structures from construction phase to maintenance stage.

• Computers and Concrete
• /
• v.6 no.1
• /
• pp.41-57
• /
• 2009

This paper presents the details of a novel external prestressing technique for strengthening of concrete members. In the proposed technique, transfer of external force is in shear mode on the end block thus creating a complex stress distribution and the required transverse prestressing force is lesser compared to conventional techniques. Steel brackets are provided on either side of the end block for transferring external prestressing force and these are connected to the anchor blocks by expansion type anchor bolts. In order to validate the technique, an experimental investigation has been carried out on post-tensioned end blocks. Performance of the end blocks have been studied for design, cracking and ultimate loads. Slip and slope of steel bracket have been recorded at various stages during the experiment. Finite element analysis has been carried out by simulating the test conditions and the responses have been compared. From the analysis, it has been observed that the computed slope and slip of the steel bracket are in good agreement with the corresponding experimental observations. A simplified analytical model has been proposed to compute load-deformation of the loaded steel bracket with respect to the end block. Yield and ultimate loads have been arrived at based on force/moment equilibrium equations at critical sections. Deformation analysis has been carried out based on the assumption that the ratio of axial deformation to vertical deformation of anchor bolt would follow the same ratio at the corresponding forces such as yield and ultimate. It is observed that the computed forces, slip and slopes are in good agreement with the corresponding experimental observations.

• PNF and Movement
• /
• v.19 no.1
• /
• pp.19-29
• /
• 2021

Purpose: This study aimed to compare the effects of a four-week scapular stabilization exercise program using the PNF technique on scapular symmetry and range of flexion motion (ROM), pain, function, and quality of life (QOL) in post-mastectomy women with breast cancer. Methods: This study included 20 women divided into an experimental group (n = 10) and a control group (n = 10). All patients performed complex decongestive physiotherapy for 40 min daily, five times per week for four weeks. The experimental group performed the extra scapular stabilizing exercise program using the PNF technique for 50 min daily, five times per week for four weeks. Scapular symmetry, shoulder flexion ROM, pain and function, and QOL were subsequently assessed. For ROM measurement, the range of shoulder flexion was measured using a clinometer smart phone application; the pain of the shoulder was measured using the visual analogue scale (VAS); the scapular position was measured using a lateral scapular slide test (LSST); the level of pain and functional activity was measured using the Shoulder Pain and Disability Index (SPADI); and the QOL was measured using Functional Assessment of Cancer Therapy-Breast. Results: There were significant differences in shoulder flexion ROM, VAS, SPADI, and LSST 0˚ and 45˚ when the experimental group was compared with the control group (p < 0.05). After the intervention, there was an improved within-group change in the ROM, SPADI, LSST, and QOL in both the experimental and control groups. Conclusion: These findings suggest that a scapular stabilization exercise program using the PNF technique may be used as a possible treatment option for post-mastectomy women with breast cancer that aims to improve scapular position, shoulder ROM and function, and QOL.

• Corrosion Science and Technology
• /
• v.20 no.2
• /
• pp.52-61
• /
• 2021

This study using experimental design and linear regression technique was implemented in order to predict the pitting potential of stainless steel in marine environments, with the target materials being AL-6XN and STS 316L. The various variables (inputs) which affect stainless steel's pitting potential included the pitting resistance equivalent number (PRNE), temperature, pH, Cl^- concentration, sulfate levels, and nitrate levels. Among them, significant factors affecting pitting potential were chosen through an experimental design method (screening design, full factor design, analysis of variance). The potentiodynamic polarization test was performed based on the experimental design, including significant factor levels. From these testing methods, a total 32 polarization curves were obtained, which were used as training data for the linear regression model. As a result of the model's validation, it showed an acceptable prediction performance, which was statistically significant within the 95% confidence level. The linear regression model based on the full factorial design and ANOVA also showed a high confidence level in the prediction of pitting potential. This study confirmed the possibility to predict the pitting potential of stainless steel according to various variables used with experimental linear regression design.

• Journal of the Korean Society for Nondestructive Testing
• /
• v.11 no.1
• /
• pp.7-12
• /
• 1991

The multi-frequency eddy current technique has been used for evaluation of various type of defects in tubings. However, this technique is not sufficient to detect and evaluate the defect in tubings if the defect is located in the geometrically complicated area(e. g. tube support plate, anti-vibration bar, tubesheet area) and mixing residue signal is significant to the defect signal. In order to improve the reliability of the multi-frequency eddy current technique, the effect of the interaction of mixing residue after frequency mixing with a function of distances between the defect and the tube support plate boundary has been analyzed theoretically. The experimental results have been discussed with the theoretical developments. The calculation shows the interaction between the two neighboring signal sources could be significant within the range of approximately 1.0mm with the experimental condition.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.22 no.8
• /
• pp.771-776
• /
• 2012

A technique is presented that uses a circular waveguide for the measurement of the bulk shear(S-wave) velocities of unconsolidated, saturated media, with particular application to near surface soils. The technique requires the measurement of the attenuation characteristics of the fumdamental T(0,1) mode that propagates along an embedded pipe, from which the acoustic properties of the surrounding medium are inferred. From the dispersion curve analysis, the feasibility of using T(0,1) mode which is non-dispersive and have constant attenuation over all frequency range is discussed. The principles behind the technique are discussed and the results of an experimental laboratory validation are presented. The experimental data are best fitted for the different depths of wetted sand and the shear velocities as a function of depths are formulated using power law curves.

• Journal of Institute of Control, Robotics and Systems
• /
• v.10 no.4
• /
• pp.341-349
• /
• 2004

In this paper, the decentralized neural network control of the reference compensation technique is proposed to control a 2-DOF inverted pendulum on an x-y plane. The cart with the 2-DOF inverted pendulum moves on the x-y plane and the 2-DOF inverted pendulum rotates freely on the x-y axis. Since the 2-DOF inverted pendulum is divided into two 1-DOF inverted pendulums, the decentralized neural network control is applied not only to balance the angle of pendulum, but also to control the position tracking of the cart. Especially, a circular trajectory tracking is tested for position tracking control of the cart while maintaining the angle of the pendulum. Experimental results show that position control of the inverted pendulum system is successful.