• Proceedings of the Korean Geotechical Society Conference
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• 2002.06a
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• pp.43-56
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• 2002

To find a lateral long term behavior of driven H-piles in embankment, inclinometer is installed at pile and measurement is done during a year. When behavior of measured slope angles is in accord with behavior of nonlinear p-y curves(Reese, Murchison and O'Neil, Matlock's p-y analysis), maximum displacement of pile head, maximum stress and maximum bending moment of pile obtained from the numerical analysis are shown. As results, maximum lateral displacement at pile head, maximum stress and maximum bending moment of pile are shown linear behavior, And maximum lateral load, maximum lateral displacement, and maximum bending moment at pile obtained from the numerical analysis are 8∼12.4tonf, 9∼10.1㎜, and 10.39∼12.67tonf-m per pile according to the curves, respectively.

• Journal of Chest Surgery
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• v.27 no.6
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• pp.494-496
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• 1994

Chondroblastoma is a rare benign bone tumor most frequently found in the epiphyseal region of long bones. The most common locations are the knee and proximal humerus,but the rib is an unusual site. Second decade is the most common age group. The ossification centers for the rib appear in the second fetal month and ossify in a caudal-to-cranial direction. There are also epiphyseal centers at the head and tubercle of the rib that appear at puberty and ossify in the third decade. The epiphyseal plates of the head and tubercle may be the site of origin of the posterior chondroblastomas; the anterior lesions may arise from the costochondral junction. The histologic features consist of polygonal chodroblast, small foci of chondroid production, osteoclast-like giant cell, and are diagnostic of chondroblastoma.We experienced a case of the chondroblastoma arising from the rib, and its clinical and histologic features are discussed.

• Journal of Korea Multimedia Society
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• v.11 no.6
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• pp.787-795
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• 2008

Human recognition on camera is an interesting topic in computer vision. While fingerprint and face recognition have been become common, gait is considered as a new biometric feature for distance recognition. In this paper, we propose a gait recognition algorithm based on the knee angle, 2 feet distance, walking velocity and head direction of a person who appear in camera view on one gait cycle. The background subtraction method firstly use for binary moving object extraction and then base on it we continue detect the leg region, head region and get gait features (leg angle, leg swing amplitude). Another feature, walking speed, also can be detected after a gait cycle finished. And then, we compute the errors between calculated features and stored features for recognition. This method gives good results when we performed testing using indoor and outdoor landscape in both lateral, oblique view.

• Journal of Information Processing Systems
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• v.19 no.3
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• pp.377-384
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• 2023

The existence of abnormal breakpoint data leads to poor channel balance in wireless sensor networks (WSN). To enhance the communication quality of WSNs, a method for positioning abnormal breakpoint data in WSNs on the basis of signal reconstruction is studied. The WSN signal is collected using compressed sensing theory; the common part of the associated data set is mined by exchanging common information among the cluster head nodes, and the independent parts are updated within each cluster head node. To solve the non-convergence problem in the distributed computing, the approximate term is introduced into the optimization objective function to make the sub-optimization problem strictly convex. And the decompressed sensing signal reconstruction problem is addressed by the alternating direction multiplier method to realize the distributed signal reconstruction of WSNs. Based on the reconstructed WSN signal, the abnormal breakpoint data is located according to the characteristic information of the cross-power spectrum. The proposed method can accurately acquire and reconstruct the signal, reduce the bit error rate during signal transmission, and enhance the communication quality of the experimental object.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.45 no.6
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• pp.77-86
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• 2008

Traditional cluster-based routing method is a representative method for increasing the energy efficiencies. In these cluster-based routing methods, the selected cluster head collect/aggregate the information and send the aggregated information to the base station. But they have to solve the unnecessary energy dissipation of frequent information exchange between the cluster head and whole member nodes in cluster. In this paper, we minimize the frequency of the information exchange for reducing the unnecessary transmit/receive frequencies as calculate the overlapped area or number of overlapped member nodes between the selected cluster head and previous cluster head in the setup phase. And besides, we consider the direction of super cluster head for optimal cluster formation. So, we propose the modified cluster selection scheme that optimizes the energy dissipation in the setup phase and reuses the saved energy in the steady phase efficiently that prolongs the whole wireless sensor network lifetime by uniformly selecting the cluster head.

• Wind and Structures
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• v.20 no.4
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• pp.549-564
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• 2015

The three-dimensional unsteady incompressible Reynolds-averaged Navier-Stokes equations and k-${\varepsilon}$ double equations turbulent model were used to investigate the effect on the measurements of anemometers due to a passing high-speed train. Sliding mesh technology in Fluent was utilized to treat the moving boundary problem. The high-speed train considered in this paper was with bogies and inter-carriage gaps. Combined with the results of the wind tunnel test in a published paper, the accuracy of the present numerical method was validated to be used for further study. In addition, the difference of slipstream between three-car and eight-car grouping models was analyzed, and a series of numerical simulations were carried out to study the influences of the anemometer heights, the train speeds, the crosswind speeds and the directions of the induced slipstream on the measurements of the anemometers. The results show that the influence factors of the train-induced slipstream are the passing head car and tail car. Using the three-car grouping model to analyze the train-induced flow is reasonable. The maxima of horizontal slipstream velocity tend to reduce as the height of the anemometer increases. With the train speed increasing, the relationship between $V_{train}$ and $V_{induced\;slipstream}$ can be expressed with linear increment. In the absence of natural wind conditions, from the head car arriving to the tail car leaving, the induced wind direction changes about $330^{\circ}$, while under the crosswind condition the wind direction fluctuates around $-90^{\circ}$. With the crosswind speed increasing, the peaks of $V_X,{\mid}V_{XY}-V_{wind}{\mid}$ of the head car and that of $V_X$ of the tail car tend to enlarge. Thus, when anemometers are installed along high-speed railways, it is important to study the effect on the measurements of anemometers due to the train-induced slipstream.

• The Journal of the Korea Contents Association
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• v.19 no.6
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• pp.471-480
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• 2019

L-spine 3~4, L-spine 4~5, and L-spine 5~Sacrum 1 intervertebral disc(IVD) angle according to gender, age, body mass index(BMI), lumbar lordosis angle(LLA) were compared and analyzed. The anteriorposterior incidence angle of L-spine 3 ~ 4, L-spine 4 ~ 5 and L-spine 5~Sacrum 1 in body mass index were 5.66, 13.23 and 29.13 degrees in the head direction and L-spine 3 4, L-spine 4 ~ 5, L-spine 5~Sacrum 1 had 6.32 degrees, 16.09 degrees and 35.36 degrees in the head direction. The distortion area ratio comparison was performed with the phantom image using the proposed incidence angle. There was a significant difference in L-spine 4~5 and L-spine 5~Sacrum 1 IVD angle relative to body mass index and LLA(p<0.05), IVD angle and LLA were positively correlated(p<0.05).As a result of evaluating the usefulness of the image by applying the incidence angles of the disc angles according to the phantom angle of deviation to the head direction as 11 degrees for L4 and 26 degrees for L5, the distortion ratio area decreased from 14.90% to 12.11% in L4, And from 15.25% to 13.72% in L5. In anteriorposterior image of the Lumbar spine applying the incidence angle according to the measured disc angle, it is possible to reduce the distortion to purpose L4, L5. And improved the quality and diagnostic information of the target site.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.717-722
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• 2003

A driving simulator is a computer-controlled tool to study an interface between a driver and vehicle response by enabling the driver to participate in judging vehicle characteristics. Using the driving simulator, human factor study, vehicle system development and other research can be effectively done under controllable, reproducible and non-dangerous conditions. An Adaptive Cruise Control (ACC) system is generally regarded as a system that can be achieved in the near future without the demanding infrastructure components and technologies. ACC system is an automatic vehicle following system with no human engagement in the longitudinal vehicle direction. And the influence of the driver is substantial in developing the system. Driving characteristic is very different according to the accident riskiness, gender, age and so on. In this research, experiments have been carried out to investigate driving characteristics with the ACC system, using a driving simulator. Participants are 21 male and 19 female. Driving characteristics such as preferred headway-time, lane keeping ability, eye direction, and head movement have been observed and compared between the driving with ACC and the driving without ACC.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2000.04b
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• pp.253-259
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• 2000

This thesis investigated the behavior of super structure by varying the factors such as the change of pile rigidity, the characteristics of soil and the constraint condition of support. The results of this study are as follows; 1. The pile rigidity in the Fig 3.3 computed by the rotating deformed plane method becomes the elastic range at approximately about 5.1 m (D : 1.0 m) below the ground level. This result is consistent with the previous study that the pile deformation occurs approximately 3 to 6 times pile diameter from the pile head. 2. The values of forces and deformations for the structure-pile system in Y-direction appeared larger than that in X-direction, since the pile rigidity and constraint condition of support were changed as shown Fig.3.5 to 3.8. 3. The current practice for the analysis of structure-pile system has not considered the variation of pile rigidity and the constraint condition of support. So, the analysis of structure-pile system with large difference in super-structure rigidity must includes these factors in both X and Y directions.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.33 no.6
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• pp.590-599
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• 2009

In this paper, a method of modeling seat belts on crew seat during dynamic seat testing was studied. The body segments of the occupant were modeled with joints. The joints consisted with various stiffnesses, dampings, and frictions. Three types of seat belt restraint systems were investigated. The analysis for on the injury assessment of helicopter's crew under drop impact was conducted. The effectiveness of the seat belt system for crashworthiness and safety was evaluated. As the results of impact analysis, head, neck and spine of the crew can be easily damaged in the vertical direction more than the longitudinal direction. Based on the verified model, behavior of human body was studied with three-point restraint systems. The displacement and injury level of the 12-point restraint system was the smallest.