• Journal of rehabilitation welfare engineering & assistive technology
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• v.8 no.3
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• pp.169-175
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• 2014

In this study, it is intended to provide a slip detector is an important function in the research on the slip control can be addressed uncontrollably path withdrawal might during driving of the power wheelchair, slip phenomenon occurs. By detecting and electric wheelchairs, the state of the motor during running, the detection of the slip, slip detection information calculated using an encoder that is connected to the left and right motor with six-axis IMU sensor for the electric wheelchair using an algorithm to calculate the slip ratio. Slip rate calculated in this way is used as control variable for improving the safety of the electric wheelchair. It was confirmed from the slip phenomenon of the path the proposed experiments slim detector proposed in this study. The maximum slip ratio detection zone during the experiment, can occur during turning of the electric wheelchair has been confirmed.

• Proceedings of the KSME Conference
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• 2001.06c
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• pp.293-298
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• 2001

In this paper, film thickness and temperature distribution are measured in EHL point contact at high roll/slip ratios. Infrared temperature mapping with two band pass filters, proposed by Ausherman (1976), is used to measure temperature distribution. And the optical interferometric method with two filters (red and green filters) is used to measure film thickness. Result of experiment showed that temperature rising at film and ball surface occurred very dramatically in Dimple zone. As slip velocity, roll/slip ratio and load increased, size of Dimple and temperature rising became more large. In addition, position and shape of Dimple were changed by roll/slip ratios, and increasing of Dimple size decreased traction coefficient. In short, it is appointed that the Dimple phenomenon be developed by the effect of viscosity wedge.

• Journal of The Geomorphological Association of Korea
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• v.26 no.1
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• pp.93-106
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• 2019

The Yangsan Fault is one of the main fault systems in the Korean peninsula. It can be divided into three segments (northern, central, and southern) by its paleoseismic and structural geologic properties. Based on the geomorphic features of the northern segment, which includes the Yugye Fault, we identified deflected streams as a geomorphic marker of strike-slip component of the fault, and knickpoints along the streams as evidence of dip-slip component of the fault. Geomorphic analyses showed that (1) the horizontal displacements of deflected streams decreased and (2) the retreat amounts of knickpoints tend to increased toward north along the lineament. We interpreted the variations caused by strain partitioning; that is, there might be some increases of the vertical component toward north, whereas the main strike-slip fault system dies out, splaying into horsetail structure toward north. Based on the response time of the landforms, these interpretations imply that (1) there were differences between horizontal slip rate and vertical slip rate along strike, and/or (2) there were different timings between horizontal and vertical deformations by fault.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.7
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• pp.84-90
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• 2003

This paper develops a control method that is composed of the proportional control algorithm and the learning algorithm based on the recurrent neural networks (RNN) for the position control of a pneumatic rodless cylinder. The proportional control algorithm is suggested for the modeled pneumatic system, which is obtained easily simplifying the system, and the RNN is suggested for the compensation of the modeling errors and uncertainties of the pneumatic system. In the proportional control, two zones are suggested in the phase plane. One is the transient zone for the smooth tracking and the other is the small movement zone for the accurate position control with eliminating the stick-slip phenomenon. The RNN is connected in parallel with the proportional control for the compensation of modeling errors and frictions, compressibilities, and parameter uncertainties in the pneumatic control system. This paper experimentally verifies the feasibility of the proposed control algorithm for such pneumatic systems.

• Journal of Mechanical Science and Technology
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• v.15 no.9
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• pp.1292-1301
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• 2001

The mean-line method using empirical models is the most practical method of predicting off-design performance. To gain insight into the empirical models, the influence of empirical models on the performance prediction results is investigated. We found that, in the two-zone model, the secondary flow mass fraction has a considerable effect at high mass flow-rates on the performance prediction curves. In the TEIS model, the first element changes the slope of the performance curves as well as the stable operating range. The second element makes the performance curves move up and down as it increases or decreases. It is also discovered that the slip factor affects pressure ratio, but it has little effect on efficiency. Finally, this study reveals that the skin friction coefficient has significant effect on both the pressure ratio curve and the efficiency curve. These results show the limitations of the present empirical models, and more resonable empirical models are reeded.

• Economic and Environmental Geology
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• v.45 no.3
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• pp.295-306
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• 2012

In this study, the Singal fault zone in the Gyeonggi massif is identified in the Kiheung area. Geotechnical investigations were carried out to locate and characterize of the Singal fault zone in the Kiheung reservoir area. The N-S striking Shingal fault is known to be a Riedel-type strike-slip fault within the Choogaryung rift. Along the fault zone, 62 bore holes were drilled and electrical resistivity survey of about 11km, and vibroseis seismic refraction and reflection survey of about 500m were done. From the result of investigations, it is found that the fault zone, consisting mainly of gouge and breccia, has maximum width of 300 meters with anastomosing geometry of secondary fractures developed subparallel to the fault zone. We interpret these geometric features to be the result of structural development of flower-structure type at the restraining band of strike-slip fault. However, there are uncertainties of this interpretation because there are virtually no outcrops in the area. Further investigation to understand geometric features and linkage style of the fault zone.

• Economic and Environmental Geology
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• v.2 no.3
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• pp.58-67
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• 1969

Songgwang lead zinc mine is located in about 12km to the north-east of Jeonju City. Geology of the mine and its visinity is consisted of Jeonju series belonged to so-called Okcheon system, Seodaesan tuff formation, Silla series, and the quartz porphyry intruded into these formations. Jeonju series comprising 3 formations; that is, of Sadaeri, Sindong, and Girinbong. Jeonju series is generally distributed in southern part of the area, striking NNW, and diping NE $30^{\circ}$, or NW $30^{\circ}$. It is deformed to form synclinorium and anticlinorium plunging to the north with low angle. In the northern part of the area, Jeonju series was cut by Sinpeongri-fault of NEE direction near Sinpeongri. In the north side of the fault, it is overturned and shows NEE or NWW strikes and NW $60^{\circ}$ dips. At the west of Songgwangri, it is cut by 3 thrusts; the two are almost parallel each other, and the third oneis manifested by the fact that the lower black shale zone thrusted over the upper limestone. Songgwangri thrust, so named, is a post-mineral fault and its plane represents a premineral slip plane. Enrichment of are took place along the bedding plane or fissure parallel to it, as seen in adit No. 1 or No. 2 along the floor of the thrust, and along the sheared zone or the brecciated zone oblique to the plane near the thrust in crystalline limestone of Sindong formation as observed in the underground levels of inclined slope. Ore minerals are chiefly zincblende, galena, pyrrhotite, arsenopyrite, acompanied pyrite and chalcopyrite, and contain Au and Ag. In earlier stage of mineralization, the limestone was recrystalized, and sulphide minerals were enriched in the· permiable zone said above by pyrometasomatism, and in later stage the limestone was affected chloritization and sericitization. However hydrothermal replacement was weak, so that enrichment did not took place. It seems that minerallizing materials came up through the premineral slip plane and injected, and replaced the limestone in permiable zone said above with sulphide are minerals. Then Songgwangri thrust took place and, the lower black shale zone thrusted upon crystalline limestone.

• Transactions of the Korean Society of Mechanical Engineers
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• v.13 no.2
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• pp.243-251
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• 1989

Assuming plastic zones spreading out on each slip plane of the two materials under out-of-plane shear loading, the size of each plastic zone is computed. The effect of the different frictional shear stresses in the two materials on the size of each plastic zone and the relative displacement at the crack tip are investigated. The relation between the J-integral in this model and the relative displacement at the crack tip is also obtained.

• Journal of the Earthquake Engineering Society of Korea
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• v.24 no.5
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• pp.219-232
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• 2020

The slip-weakening model developed by Ohnaka and Yamashita is extended over the breakdown zone by equating the scaling relationships for the breakdown zone and the whole rupture area. For the extension, the study uses the relationship between rupture velocity and radiation efficiency, which was derived in the theory of linear elastic fracture mechanics, and the definition of f_max given in the specific barrier model proposed by Papageorgiou and Aki. The results clearly show that the extended scaling relationship is governed by the ratio of rupture velocity to S wave velocity, and the velocity ratio can be determined by the ratio of characteristic frequencies of a Fourier amplitude spectrum, which are corner frequency, f_c, and source-controlled cut-off frequency, f_max, or vice versa. The derived relationship is tested by using the characteristic frequencies extracted from previous studies of more than 130 shallow crustal events (focal depth less than 25 km, M_W 3.0~7.5) that occurred in Japan. Under the assumption of a dynamic similarity, the rupture velocity estimated from f_max/f_c and the modified integral timescale give quite similar scale-dependence of the rupture area to that given by Kanamori and Anderson. Also, the results for large earthquakes show good agreement to the values from a kinematic inversion in previous studies. The test results also indicate the unavailability of the spectral self-similarity proposed by Aki because of the scale-dependent rupture velocity and the rupture velocity-dependent f_max/f_c; however, the results do support the local similarity asserted by Ohnaka. It is also remarkable that the relationship between the rupture velocity and f_max/f_c is quite similar to Kolmogorov's hypothesis on a similarity in the theory of isotropic turbulence.

• Economic and Environmental Geology
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• v.30 no.5
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• pp.459-467
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• 1997

In order to examine the primary trends and characteristics of geological lineaments along the southwestern boundary of Okcheon zone, we carried out the analysis of geological lineament trends over six selected sub-areas using Landsat-5 TM images and digital elevation model. The trends of lineaments is determined by a minimum variance method, and the resulting geological lineament map can be obtained through generalized Hough transform. We have corrected look direction biases reduces the interpretability of remotely sensed image. An approach of histogram modification is also adopted to extract drainage pattern specifically in alluvial plains. The lineament extracting method adopted in this study is very effective to analyze geological lineaments, and that helps estimate geological trends associated various with the tectonic events. In six sub-areas, the general trends of lineaments are characterized NW, NNW, NS-NNE, and NE directions. NW trends in Cretaceous volcanic rocks and Jurassic granite areas may represent tension joints that developed by rejuvenated end of the Early Cretaceous left-lateral strike-slip motion along the Honam Shear Zone, while NE and NS-NNE trends correspond to fault directions which are parallel to the above Shear Zone. NE and NW trends in Granitic Gneiss are parallel to the direction of schitosity, and NS-NNE and NE trends are interpreted the lineation by compressive force which acted by right-lateral strike-slip fault from late Triassic to Jurassic. And in foliated Granite, NE and NNE trends are coincided with directions of ductile foliation and Honam Shear Zone, and NW-NNW trends may be interpreted direction of another compressional foliation (Triassic to Early Jurassic) or end of the Early Cretaceous tensional joints. We interpreted NS-NNE direction lineation is related with the rejuvenated Chugaryung Fault System.