• Proceedings of the Korean Vacuum Society Conference
• /
• 2016.02a
• /
• pp.341-341
• /
• 2016

The discovery of light emission in nanostructured silicon has opened up new avenues of research in nano-silicon based devices. One such pathway is the application of silicon quantum dots in advanced photovoltaic and light emitting devices. Recently, there is increasing interest on the silicon quantum dots (c-Si QDs) films embedded in amorphous hydrogenated silicon-nitride dielectric matrix (a-SiNx: H), which are familiar as c-Si/a-SiNx:H QDs thin films. However, due to the limitation of the requirement of a very high deposition temperature along with post annealing and a low growth rate, extensive research are being undertaken to elevate these issues, for the point of view of applications, using plasma assisted deposition methods by using different plasma concepts. This work addresses about rapid growth and single step development of c-Si/a-SiNx:H QDs thin films deposited by RF (13.56 MHz) and ultra-high frequency (UHF ~ 320 MHz) low-pressure plasma processing of a mixture of silane (SiH4) and ammonia (NH3) gases diluted in hydrogen (H2) at a low growth temperature ($230^{\circ}C$). In the films the c-Si QDs of varying size, with an overall crystallinity of 60-80 %, are embedded in an a-SiNx: H matrix. The important result includes the formation of the tunable QD size of ~ 5-20 nm, having a thermodynamically favorable <220> crystallographic orientation, along with distinct signatures of the growth of ${\alpha}$-Si3N4 and ${\beta}$-Si3N4 components. Also, the roles of different plasma characteristics on the film properties are investigated using various plasma diagnostics and film analysis tools.

• The Journal of Engineering Geology
• /
• v.16 no.4 s.50
• /
• pp.437-453
• /
• 2006

More than 3,000 landslides were occurred by torrential rains in Gangneung area due to the typhoon Rusa in 2002. In order to analyze the landslide origin and its geometric characteristics, 1,365 landslide data were collected from the field survey of Sacheon, Jumunjin, and Yeongok areas in which the intensive landslides took place. The average landslide size in the study area was composed of 10m width, 30m length, and $21^{\circ}{\sim}35^{\circ}$ slope angle, and the plane view of landslides A-type (i.e. wide shape of lower part) that contains approximately 50.5% of the landslides commonly occurred. In particular the area of Sacheon heavily damaged by mountain fires had more occurrence of landslides than other areas. The landslides of uniform tendency of slope direction were examined resulted from the contribution of topographic characteristics due to the weathering and wind direction during heavy rainfalls. In order to analyze the direction of joint, 249 orientation data were collected from the study area. The window method was employed to determine the characteristics of joint density in 51 locations of the study area. The results showed that many landslides occurred in the areas of joint density with the range of $0.05{\sim}0.1$.

• Tunnel and Underground Space
• /
• v.17 no.2 s.67
• /
• pp.139-151
• /
• 2007

Stereophotogrammetry is a method to extract information of an interested area by constructing a stereo-image from two or more photos. In this study, the stereophotogrammetry was adopted to obtain the joint orientation and trace length from a sampling window and its measurements were compared with the result by a clinocompass and measuring tape to evaluate the applicability of the stereophotogrammetry to rock joint survey. A commercial stereophotogrammetry program, ShapeMetriX 3D, was used for this purpose. Firstly, the accuracy of the measuring method using ShpaeMetrix 3D was evaluated by a model test. Secondly, joint orientations on a rock slope and tunnel were obtained by using ShapeMetriX 3D and compared with the measurement by a clinocompass. Finally. the effect of base-depth ratio in photographing was evaluated by comparing images with various base-depth ratios, and the usefulness of closed-up photographing on a rock exposure to increase the measurement accuracy was tested. The dip and dip direction of each model plane obtained by ShapeMetriX 3D showed an error ranged between $-5^{\circ}\;and\; 5^{\circ}$ on the basis of the results by the measuring tape. Base-depth ratio proved not to influence the analysis result by ShapeMetriX 3D if all the images were taken without any hidden area. The close-up photographing turned out useful to obtain the detailed images and therefore precise result when ShapeMetriX 3D was adopted.

• Journal of the Korean Orthopaedic Association
• /
• v.56 no.5
• /
• pp.413-418
• /
• 2021

Purpose: To investigate the effect of facet tropism on the degeneration of facet joint and intervertebral disc in the cervical spine. Materials and Methods: From January 2017 to December 2018, cervical tropism of 100 patients at the C5/6 level was analyzed retrospectively. In computed tomography (CT), the orientation and tropism of the facet joint with respect to the sagittal, coronal, and horizontal planes were measured. Regression of the facet joint in magnetic resonance imaging (MRI) and CT was assessed using a grading system. Intervertebral disc degeneration was assessed and divided into five grades on MRI. For the left and right asymmetry, a difference between two facet angles of less than 7° was classified as the control group, more than 7° was classified as the tropism group. Results: The mean age of the patients was 55.44±12.3 years (31-81 years) in the tropism group and 55.66±10.7 years (32-76 years) in the control group. In the tropism group, 32 were male and 18 were female. In the control group, 24 were male and 26 were female. Facet joint degeneration was identified in 24 patients (48.0%) in the tropism group and 14 patients (28.0%) in the control group, showing a significant difference. Intervertebral disc degeneration was identified in 29 patients (58.0%) in the tropism group and 17 patients (34.0%) in the control group, showing a significant difference. Multivariate revealed, tropism to be a factor that affected the facet joint and intervertebral disc degeneration. Conclusion: Facet joint and intervertebral disc degeneration occurred significantly in the tropism group, and tropism is a factor affecting the degeneration of facet joint and intervertebral disc in the C5/6 level.

• The Journal of Engineering Geology
• /
• v.18 no.4
• /
• pp.459-470
• /
• 2008

Types of slope failure related to cut slope stability are interpreted through case analyses, and also factors affecting structurally controlled instability investigated, which are developed by geologic structures along a national road No. 25 across the Cheongwon and Boeun-Guns, Chungbuk. Engineering properties such as orientation, persistence, roughness and uniaxial compressive strength of joints are analyzed by square-inventory method in three areas with well-preserved outcrops. The study area is located in Ogcheon folded bet, and are composed of quartz-schist and quartzite in the Midongsan Formation and phyllite in the Ungyori Formation. Flexural beds by folding, schistosity and cleavage besides joints are developed due to slight metamorphism. Various types of joints developed by folding are formed such as strike-parallel, strike-perpendicular, wedge and wrench joint sets by both initially regional and later superposed folding. Factors of slope instability are created by crossing the orientations of joint, cleavage, bedding and slope one another. In the case that the orientation of a slope is coincident with one of beds, factors causing large-scale failure including plane failure are increased greatly. Also in the region that orientations of the slope and bed are crossed each other at high angle, only local and minor failures are shown in the slope.

• Journal of Broadcast Engineering
• /
• v.17 no.3
• /
• pp.447-458
• /
• 2012

We present a method to recognize hand gestures using skeletal joint data obtained from Microsoft's Kinect sensor. We propose a combination feature of multi-angle histograms robust to orientation variations to represent the observation sequence of skeletons. The proposed feature efficiently represents the orientation variations of gestures that can be occurred according to person or environment by combining the multiple angle histograms with various angular-quantization levels. The gesture represented as combination of multi-angle histograms and random decision forest classifier improve the recognition performance. We conduct the experiments in hand gesture dataset obtained from a kinect sensor and show that our method outperforms the other methods by comparing the recognition performance.

• Tunnel and Underground Space
• /
• v.29 no.5
• /
• pp.332-345
• /
• 2019

Maximum dip vector of individual joint plane, which can be uniquely defined on the hemispherical projection plane, has been established by considering its dip and dip direction. A new stereographic projection method for the rock slope analysis which employs the maximum dip vector can intuitively predict the failure modes of rock slope. Since the maximum dip vector is uniquely projected on the maximum dip point of the great circle, the sliding direction of discontinuity plane can be recognized directly. By utilizing the maximum dip vector of discontinuity both the plane sliding and toppling directions of corresponding blocks can be discerned intuitively. Especially, by allocating the area of high dip maximum dip vector which can form the flanks of sliding block the potentiality for the formation of virtual sliding block has been estimated. Also, the potentiality of forming the triangular-sectioned sliding block has been determined by considering the dip angle of joint plane the dip direction of which is nearly opposite to that of the slope face. Safety factors of the different-shaped blocks of triangular section has been estimated and compared to the safety factor of the most hazardous block of rectangular section. For the wedge analysis the direction of crossline of two intersecting joint planes, which has same attribute of the maximum dip vector, is used so that wedge failures zone can be superimposed on the stereographic projection surface in which plane and toppling failure areas are already lineated. In addition the maximum dip vector zone of wedge top face has been delineated to extract the wedge top face-forming joint planes the orientation of which provides the vital information for the analysis of mechanical behavior of wedge block.

• Tunnel and Underground Space
• /
• v.19 no.1
• /
• pp.31-42
• /
• 2009

One set of hardware system of guide point method (GP method), modified from the multistage convergent photographing technique, was developed to interpret the geometrical characteristics of Joints photogrammetrically on rock slope. Before the field application of the hardware system, the level of errors and constraints that ran be acceptable in the field measurement has been severely investigated in the laboratory and the optimum photographing scheme was analyzed. The range of the most suitable convergence angle between two cameras was $25^{\circ}{\sim}150^{\circ}$ and the photographing distance was about 5.5 m when using a 2 M pixel digital camera. An extended analyzing technique, which was newly developed in this study, was applied to the field measurement to magnify the benefits of GP method. This technique can be applied when survey for the wide range of rock surface is necessary. The global coordinates of ground control points for the neighbor photographing area ran be introduced without any preparation from the previous photographed area using this technique. It could reduce phographing time in the field.

• Journal of the Korea Computer Graphics Society
• /
• v.19 no.4
• /
• pp.13-22
• /
• 2013

A motion capture system is widely used in movies, computer game, and computer animation industries because it allows for creating realistic human motions efficiently. The inertial motion capture system has several advantages over more popular vision-based systems in terms of the required space and cost. However, it suffers from low accuracy due to the relatively high noise levels of the inertial sensors. In particular, the accelerometer used for measuring gravity direction loses the accuracy when the sensor is moving with non-zero linear acceleration. In this paper, we propose a method to remove the linear acceleration component from the accelerometer data in order to improve the accuracy of measuring gravity direction. In addition, we develop a simple method to calibrate the joint axis of a link to which an inertial sensor belongs as well as the position of a sensor with respect to the link. The calibration enables attaching inertial sensors in an arbitrary position and orientation with respect to a link.

• The Journal of Engineering Geology
• /
• v.11 no.1
• /
• pp.101-113
• /
• 2001

Structural and geological engineering properties of the rock mass distributed in the Yokmang mountain area were investigated to detenninc the usable cut-out volume and quarrying efficiency. The study area is located in the southern tip of the Yangsan fault system which controls the geological structure of the Kvungsang basin. As a result, the study area is mainly composed of andesicic. rhyolitic. and granitic rocks of the Cretaceous Kyungsang Supergroup and a series of right-handed strike-slip faults is developed along NNE-SSW direction. These regional faults significantly affect the spatial and meclwnical characteristics of joints such as spacing, frequency, and compressive strength. The joint frequency is highest along the fault zones and decreases toward the remote region. Based on the geological information obtained from the field survey, the detailed structure of the Yokmang mountain was analyzed and the volume of the rock mass was assessed. Considering the minimum rock block size required for the construction of a coastal dumping site, potential cut-out volume is then estimated to be 4,018,000m$^3$ the volume % of which is 48% of Yokmang mountain including the soil and weathered rock and 61% of the unweathered rock mass.