• Journal of the Korea Concrete Institute
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• v.16 no.6 s.84
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• pp.823-832
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• 2004

The purpose of this research is to investigate the flexure-shear behavior of bridge columns under seismic loads. Four full scale circular reinforced concrete columns were tested under cyclic lateral load with constant axial load. The selected test variables are aspect ratio(1.825, 2.5, 4.0), transverse steel configuration, and longitudinal steel ratio. Volumetric ratio of transverse hoop of all the columns is 0.0023 in the plastic hinge region. It corresponds to $24\%$ of the minimum requirement of confining steel by Korean Bridge Design Specifications, which represent existing columns not designed by the current seismic design specifications or designed by limited ductility concept. The columns showed flexural failure or flexure-shear failure depending on the test variables. Failure behavior and seismic performance are investigated and discussed in this paper.

• Transactions of the Korean Society of Automotive Engineers
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• v.24 no.2
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• pp.255-263
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• 2016

Lane Keeping Assistance System (LKAS) is a kind of Advanced Driver Assistance Systems (ADAS) which are developed to automate/ adapt/ enhance vehicle systems for safety and better driving. The main system function of LKAS is to support the driver in keeping the vehicle within the current lane. LKAS acquires information on the position of the vehicle within the lane and, when required, sends commands to actuators to influence the lateral movement of the vehicle. Recently, the vehicles equipped with LKAS are commercially available in a few vehicle-advanced countries and the installation of LKAS increases for safety enhancement. The test procedures for LKAS evaluations are being discussed and developed in the international committees such as ISO (the International Organization for Standardization) and UNECE (United Nations Economic Commission for Europe). In Korea, the evaluations of LKAS for vehicle safety are planned to be introduced in 2016 KNCAP (Korean New Car Assessment Program). Therefore, the test procedures of LKAS suitable for domestic road and traffic conditions, which accommodate international standards, should be developed. In this paper, some bullet points of the test procedures for LKAS are discussed and proposed by extensive researches of previous documents and reports, which are released in public in regard to lateral test procedures including LKAS and Lane Departure Warning System (LDWS). And then, to evaluate the validity of the proposed test procedures, a series of experiments were conducted using commercially available two vehicles equipped with LKAS. Later, it can be helpful to make a draft considering domestic traffic situations for test procedures of LKAS.

• Tribology and Lubricants
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• v.33 no.3
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• pp.92-97
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• 2017

The understanding of the friction characteristics of micro-textured surface is of great importance to enhance the tribological properties of nano- and micro-devices. We fabricate rectangular patterns with submicron-scale structures on a Si wafer surface with various pitches and heights by using a focused ion beam (FIB). In addition, we fabricate tilted rectangular patterns to identify the influence of the tilt angle ($45^{\circ}$ and $135^{\circ}$) on friction behaviour. We perform the friction test using lateral force microscopy (LFM) employing a colloidal probe. We fabricate the colloidal probe by attaching a $10{\pm}1-{\mu}m$-diameter borosilicate glass sphere to a tipless silicon cantilever by using a ultraviolet cure adhesive. The applied normal loads range between 200 nN and 1100 nN and the sliding speed was set to $12{\mu}m/s$. The test results show that the friction behavior varied depending on the pitch, height, and tilt angle of the microstructure. The friction forces were relatively lower for narrower and deeper pitches. The comparison of friction force between the sub-micro-structured surfaces and the original Si surface indicate an improvement of the friction property at a low load range. The current study provides a better understanding of the influence of pitch, height, and tilt angle of the microstructure on their tribological properties, enabling the design of sub-micro- and micro-structured Si surfaces to improve their mechanical durability.

• Journal of the Korea Concrete Institute
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• v.17 no.1 s.85
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• pp.51-58
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• 2005

Moment frames have been widely used in building construction. In current design codes, concrete moment frames are classified into ordinary, intermediate, and special moment resisting concrete frames (OMRCF, IMRCF, SMRCF)). The objective of this study is to investigate the seismic behavior of columns in ordinary moment resisting concrete frames (OMRCF) and intermediate moment resisting concrete frames (IMRCF). For this purpose 3 story OMRCF and IMRCF buildings were designed and detailed in compliance to ACI 318 (2002) and KCI (1999). In this study the buildings were assumed to be located in seismic zone 1 classified by UBC (1997). This study considered the columns in the 1st story since these columns shall resist the largest axial and lateral forces during an earthquake. Eight 2/3 scale column specimens were made for representing the upper part and lower part of exterior and interior columns of the OMRCF and the IMRCF Quasi-static reversed cyclic loading was applied to each specimen with a constant or varying axial load. Test results show that seismic behaviors of columns are influenced by existence of lap splices, axial force levels, and lateral reinforcement at possible plastic hinging region. However, the effect of such variables strongly co-related to each other.

• Annals of Clinical Neurophysiology
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• v.19 no.2
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• pp.101-112
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• 2017

Detection of underling proteinopathies is becoming increasingly important across neurodegenerative conditions due to upcoming disease intervention trials. In this review, we explored how temporal lobe changes in amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) can potentially predict underlying TDP-43 pathology subtypes in FTD. To date, emphasis has been given to frontal lobe changes in the study of the cognitive and behavioural impairments in both syndromes but an increasing number of pathological, imaging and neuropsychological studies suggest how temporal lobe changes could critically affect the cognition and behaviour of these conditions. In this current article, we reviewed pathological, imaging as well as clinical/neuropsychological findings of temporal involvement in the ALS-FTD continuum, how they relate to temporal lobe changes and the underlying TDP-43 pathology in FTD. Findings across studies show that TDP-43 pathology occurs and coincides in many structures in ALS and FTD, but especially in the temporal lobes. In particular, anterior and medial temporal lobes atrophy is consistently found in ALS and FTD. In addition, memory and language impairment as well as emotional and Theory of Mind processing deficits that are characteristics of the two diseases are highly correlated to temporal lobe dysfunction. We conclude by showing that temporal lobe changes due to TDP-43 type B might be particular predictive of TDP-43 type B pathology in behavioural variant FTD, which clearly needs to be investigated further in the future.

• Journal of Biomedical Engineering Research
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• v.36 no.5
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• pp.228-234
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• 2015

The balance ability significantly decreased in the elderly because of deterioration of the neural musculature regulatory mechanisms. Several studies have investigated methods of improving balance ability using real-time systems, but it is limited by the expensive test equipment and specialized resources. Recently, Kinect system based on depth data has been applied to address these limitations. Little information about accuracy/inaccuracy of Kinect system is, however, available, particular in motion analysis for evaluation of effectiveness in rehabilitation training. Therefore, the aim of the current study was to evaluate accuracy/inaccuracy of Kinect system in specific rotational movement for balance rehabilitation training. Six healthy male adults with no musculoskeletal disorder were selected to participate in the experiment. Movements of the participants were induced by controlling the base plane of the balance training equipment in directions of AP (anterior-posterior), ML (medial-lateral), right and left diagonal direction. The dynamic motions of the subjects were measured using two Kinect depth sensor systems and a three-dimensional motion capture system with eight infrared cameras for comparative evaluation. The results of the error rate for hip and knee joint alteration of Kinect system comparison with infrared camera based motion capture system occurred smaller values in the ML direction (Hip joint: 10.9~57.3%, Knee joint: 26.0~74.8%). Therefore, the accuracy of Kinect system for measuring balance rehabilitation traning could improve by using adapted algorithm which is based on hip joint movement in medial-lateral direction.

• Journal of the Korean Arthroscopy Society
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• v.2 no.1
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• pp.25-32
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• 1998

The distinction between isolated and combined injuries is crucial both for treatment and prognosis. For most combined injuries, surgical treatment continues to be favored over nonoperative treatment. It is generally agreed that isolatel PCL injuries do well without surgery. There has been an interest by many authors to fix the graft directly to the posterior aspect of the tibia(tibial inlay). With this procedure, tibial graft fixation will be more direct and theoretically reduce the bending effects of the graft with a fixation site far away from the tibial insertion. Modified tibial inlay technique, which is the posterior approach does not require the patient to be in the prone or lateral decubitus position during the operation. Use of a double-bundle reconstructive technique is attractive and has been performed by some surgeons. At this time, this procedure is still being investigated and should not be routinely used in the clinical setting until studies have indicated an advantage over current single-bundle techniques. However theologically, double-bundle reconstructive technique is more useful in severe posterior unstable knee. Recent advances have increased our knowledge of the anatomy and mechanical characteristics of the PCL. Basic science research has further increased our awareness of the interaction of the posterolateral structures with the PCL. To achieve restoration of normal posterior laxity, it is critical to address the posterior as well as the postero-lateral structures. Surgical treatment is often complex and requires a wide range of surgical techniques and skills to treat associated injuries. When the PCL is reconstructed, most surgeons choose to reconstruct the anterolateral component using a graft of sufficient size and strength. The initial postoperative rehabilitation should be addressed cautiously in an effort to avoid excessive forces on delicate repairs and reconstructions in these complex injuries. Further research is necessary to evaluate new surgical approaches such as double-bundle reconstructions and tibial inlay techniques as well as improved techniques for capsular and collateral ligament injuries.

• Journal of the Korea Concrete Institute
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• v.15 no.6
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• pp.856-865
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• 2003

Current design provisions and guide for performance-based design do not accurately evaluate seismic performance of flat plate system. In the previous companion studies, parametric studies using nonlinear finite element analyses were performed to investigate behavior of the flat plate, and based on the numerical results, design methods that can predict the bending moment-carrying capacity and the corresponding deformability of the flat plate was developed. In the present study, a generalized moment-rotation relation of the flat plate was developed based on the previous studies and the numerical analyses. The proposed method was verified by the comparisons with existing experiments. In addition, the effective stiffness of the flat plate corresponding to 0.2 percent of lateral drift that is generally regarded as the serviceability limit was proposed, so as to evaluate conveniently deflection of the structure subject to wind load.

• Physical Therapy Korea
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• v.22 no.2
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• pp.41-51
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• 2015

The purposes of this study were 1) to determine the effects of low-dye taping on peak plantar pressure following treadmill walking exercise, 2) to determine whether the biomechanical effectiveness of low-dye taping in peak plantar pressure was still maintained following removal of the tape during treadmill walking, and 3) to determine the trend towards a medial-to-lateral shift in peak plantar pressure in the midfoot region before and after application of low-dye taping. Twenty subjects with flexible flatfoot were recruited using a navicular drop test. The peak plantar pressure data were recorded during five treadmill walking sessions: (1) un-taped, (2) baseline-taped, (3) after a 10-minute treadmill walking exercise, (4) after a 20-minute treadmill walking exercise, and (5) after removal of the taping. The foot was divided into six parts during the data analysis. One-way repeated measures analysis of variance was performed to investigate peak plantar pressure variations in the six foot parts in the five sessions. This study resulted in significantly increased medial forefoot peak plantar pressure compared to the un-taped condition (p=.017, post 10-minute treadmill walking exercise) and (p=.021, post 20-minute treadmill walking exercise). The peak plantar pressure in the lateral forefoot showed that there was a significant decrease after sessions of baseline-taped (p=.006) and 10-minute of treadmill walking exercise (p=.46) compared to the un-taped condition. The tape removal values were similar to the un-taped values in the five sessions. Thus, the findings of the current study may be helpful when researchers and clinicians estimate single taping effects or consider how frequently taping should be replaced for therapeutic purposes. Further studies are required to investigate the evidence in support of biomechanical effectiveness of low-dye taping in the midfoot region.

• Journal of the Korea Concrete Institute
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• v.25 no.5
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• pp.529-537
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• 2013

The aim of the current study is to develop a nonlinear isoparametric layered frame finite element (FE) analysis of FRP strengthened reinforced concrete (RC) beam or column members by a force-based FE formulation. In sections, concrete is modeled in the triaxial stress-strain relationship state and the FRP sheet is modeled as layered composite materials in two-dimension. The element stiffness matrix derived by the force-based FE has the force-interpolation functions without assuming the displacement shape functions. A lateral load test of RC column strengthened by GFRP sheets was analyzed by the developed force-based FE model. From comparative studies of the experimental and analysis results, it was shown to compare with the stiffness FE method that the force-based FE analysis could give more accurate predictions in the overall lateral load-deflection response as well as in nonlinear deformations and damages in the column plastic hinge region.