• Journal of Astronomy and Space Sciences
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• v.32 no.3
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• pp.201-207
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• 2015

An algorithm to automatically extract coordinate and time information from optical observation data of geostationary orbit satellites (GEO satellites) or geosynchronous orbit satellites (GOS satellites) is developed. The optical wide-field patrol system is capable of automatic observation using a pre-arranged schedule. Therefore, if this type of automatic analysis algorithm is available, daily unmanned monitoring of GEO satellites can be possible. For data acquisition for development, the COMS1 satellite was observed with 1-s exposure time and 1-m interval. The images were grouped and processed in terms of "action", and each action was composed of six or nine successive images. First, a reference image with the best quality in one action was selected. Next, the rest of the images in the action were geometrically transformed to fit in the horizontal coordinate system (expressed in azimuthal angle and elevation) of the reference image. Then, these images were median-combined to retain only the possible non-moving GEO candidates. By reverting the coordinate transformation of the positions of these GEO satellite candidates, the final coordinates could be calculated.

• The Journal of Engineering Geology
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• v.11 no.3
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• pp.279-294
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• 2001

When constructing subsurface structures and drilling wells, the precise hydraulic parameters must be obtained for operating safety and for developing enough quantity of groundwater, respectively. In this study we conducted water injection test at different depths on six boreholes drilled in the granite of Mt. Geumjeong. Hydraulic conductivity was calculated using Moye and Hvorslev methods. The relation between hydraulic conductivity and fracture frequency data obtained from acoustic televiewer and core log was analyzed. From the result, though the correlation coefficient between the hydraulic conductivity and the fracture frequency from acoustic televiewer data is higher than that between the hydraulic conductivity and the fracture frequency from core log data on most of the test holes, the correlation coefficient between the hydraulic conductivity and the fracture frequency from the televiewer data is lower than 0.5. This suggests that the hydraulic conductivity of granite in the study area is influenced not only by the fracture frequency but also by various factors of fracture network such as fracture aperture and length, interconnectivity of fractures, fracture orientation and angle, filling material and so on.

• The Bulletin of The Korean Astronomical Society
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• v.39 no.1
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• pp.73-73
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• 2014

Several geometrical models (e.g., cone and flux rope models) have been suggested to infer 3-D parameters of CMEs using multi-view observations (STEREO/SECCHI) and single-view observations (SOHO/LASCO). To prepare for when only single view observations are available, we have made a test whether the cone model parameters from single-view observations are consistent with those from multi-view ones. For this test, we select 35 CMEs which are identified as CMEs, whose angular widths are larger than 180 degrees, by one spacecraft and as limb CMEs by the other ones. For this we use SOHO/LASCO and STEREO/SECCHI data during the period from 2010 December to 2011 July when two spacecraft were separated by $90{\pm}10$ degrees. In this study, we compare 3-D parameters of these CMEs from three different methods: (1) a triangulation method using the STEREO/SECCHI and SOHO/LASCO data, (2) a Graduated Cylindrical Shell (GCS) flux rope model using the STEREO/SECCHI data, and (3) an ice cream cone model using the SOHO/LASCO data. The parameters used for comparison are radial velocities, angular widths and source location (angle ${\gamma}$ between the propagation direction and the plan of the sky). We find that the radial velocities and the ${\gamma}$-values from three methods are well correlated with one another (CC > 0.8). However, angular widths from the three methods are somewhat different. The correlation coefficients are relatively not good (CC > 0.4). We also find that the correlation coefficients between the locations from the three methods and the active region locations are larger than 0.9, implying that most of the CMEs are radially ejected.

• Journal of the Korean Institute of Landscape Architecture
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• v.26 no.3
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• pp.78-78
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• 1998

The purpose of this research is to develop a CAD-based program for data analysis of digital elevation model(DEM) on the aspect of landscape assessment. When handling DEM data as a visual simulation of topographic landscape, it is basic interest to analyze visible area and visualize visual sensitivity distributions. In reference with landscape assessment, more intuitive and interactive visualizing tools are needed, specially in area of visual approach. For adaptability to landscape assessment, algorithmic approaches to visibility analysis and concepts for visual sensitivity calculation in this study were based on processing techniques of entity data control functions used in AutoCAD drawing database. Also, for the purpose of quantitative analysis, grid-type 3DFACE entities were adopted as mesh unit of DEM structure. Developed programs are composed of main part named VSI written in AutoLISP and two of interface modules written in dialog control language(DCL0 for user-oriented interactive usage. Definitions of camera points(view points) and target points(or observed area) are available alternatively in combined methods of representing scenic landscape, scenery, and sequential landscape. In the case of scene landscape(single camera to fixed target point), only visibility analysis in available. And total visibility, frequency of cumulative visibility, and visual sensitivity analysis are available in other cases. Visual sensitivity was thought as view angle(3 dimensional observed visual area) and the strengths were classified in user defined level referring to statistical characteristics of distribution. Visibility analysis routine of the VSI was proved to be more effective in the accuracy and time comparing with similar modules of existing AutoCAD third utility.

• The Bulletin of The Korean Astronomical Society
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• v.45 no.1
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• pp.42.2-42.2
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• 2020

We report on multi-wavelength observations of AA Ori, a Young Stellar Object in Orion-A star-forming region. AA Ori is known to have a pre-transitional disk based on infrared observations including Spitzer/IRS data. We construct its broadband spectral energy distribution (SED) by not only taking data in the optical and IR region but also including Herschel/PACS, JCMT/SCUBA, and SMA observational data. We use the Monte Carlo radiative transfer code (RADMC-3D) to reconstruct the SED with a viscous accretion disk model initialized by a radially continuous disk and finally having an inner and outer dusty disk separated by a dust-depleted radial gap. By comparing the model SEDs with different configurations of disk parameters, we discuss the limits to find a single solution of model parameters to fit the data. We suggest that some models with a modified inner disk surface density gradient and some degree of dust depletion in the inner disk can explain the AA Ori's SED, from which we infer that the inner disk of AA Ori has evolved. We present that model configurations of a pre-transitional disk with a large gap extended to 60-80 AU in a settled dusty disk of a few hundred AU size with a high inclination angle (~60°) also create model SEDs close to the observed one. To distinguish whether the disk has a just-opened narrow gap or a large gap, with an altered surface density of the inner disk extended to 10 AU, we suggest a further investigation of AA Ori with high angular resolution observations.

• Geomechanics and Engineering
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• v.37 no.5
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• pp.475-498
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• 2024

The prediction of the susceptibility of soil to liquefaction using a limited set of parameters, particularly when dealing with highly unbalanced databases is a challenging problem. The current study focuses on different ensemble learning classification algorithms using highly unbalanced databases of results from in-situ tests; standard penetration test (SPT), shear wave velocity (V_s) test, and cone penetration test (CPT). The input parameters for these datasets consist of earthquake intensity parameters, strong ground motion parameters, and in-situ soil testing parameters. liquefaction index serving as the binary output parameter. After a rigorous comparison with existing literature, extreme gradient boosting (XGBoost), bagging, and random forest (RF) emerge as the most efficient models for liquefaction instance classification across different datasets. Notably, for SPT and V_s-based models, XGBoost exhibits superior performance, followed by Light gradient boosting machine (LightGBM) and Bagging, while for CPT-based models, Bagging ranks highest, followed by Gradient boosting and random forest, with CPT-based models demonstrating lower G_mean(error), rendering them preferable for soil liquefaction susceptibility prediction. Key parameters influencing model performance include internal friction angle of soil (ϕ) and percentage of fines less than 75 µ (F₇₅) for SPT and V_s data and normalized average cone tip resistance (q_c) and peak horizontal ground acceleration (a_max) for CPT data. It was also observed that the addition of V_s measurement to SPT data increased the efficiency of the prediction in comparison to only SPT data. Furthermore, to enhance usability, a graphical user interface (GUI) for seamless classification operations based on provided input parameters was proposed.

• Korean Journal of Applied Biomechanics
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• v.12 no.2
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• pp.77-90
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• 2002

This study serves the purpose of understanding about correct jump and landing motion through Kinematical Analysis of Straddle Jump to Push up Motion at target by four elite sports aerobics athletes have more than four years career. And further more that make good assistance for coaches effective guidance through an offer basic data and correct diagnosis, evaluate of motions. It was picture-taked by two-video camera for Straddle Jump to Push up Motions. Camera speeds are 60 frame/sec. There are Kinematical Variation elements for analysis, the displacement of COG, each angle displacement left/right of shoulder-joint, each angle displacement left/right of knee-joint and each speed left/right of tip of the toes. Every each person accomplished severaly 3 times and we have acquired this conclusion. The conclusions were as follows; 1. Each situation for displacement of COG showed low height of COG by phase 1, 4, 5(79.05${\pm}9.07,\;46.41{\pm}3.65,\;18.66{\pm}0.54cm$) and It showed high height of COG by phase 2, 3($120.80{\pm}6.13,\;148.12{\pm}9.19cm$). 2. Each displacement left, right of shoulder-joint flexion by phase 1($91.07{\pm}8.30,\;90.77{\pm}5.72$deg/sec)and It showed maximal extension angles by phase 2($102.48{\pm}10.00,\;102.39{\pm}10.51$deg/sec). in part of phase 3, left of shoulder-joint angle($94.43{\pm}4.12$deg/sec) showed flexion phase 1, the other right shoulder-joint angle(88.38${\pm}$4.98deg/sec) showed more a little lower than phase 1, in last phase that showed most low by phase 4($70.58{\pm}13.72,\;54.24{\pm}11.58$deg/sec). 3. Each displacement left, right of hip joint showed maximal extent conditions by phase 2, 3($160.35{\pm}22.68,\;1534.77{\pm}5.40$deg/sec, $150.04{\pm}12.79,\;145.54{\pm}13.00$deg/sec) beside, ankle-joint showed minimal angle by phase 1, 4($93.59{\pm}18.92,\;85.37{\pm}13.23$deg/sec, $66.60{\pm}15.77,\;80.60{\pm}16.57$deg/sec). 4. Each displacement left, right of hip joint showed maximal extent conditions by phase 2($157.15{\pm}9.13,\;163.52{\pm}8.18$deg/sec), and right of hip joint showed minimal angle by phase 3($110.87{\pm}13.81,\;77.53{\pm}8.95$deg/sec) It showed alike condition of low angle by phase 1, 4($91.04{\pm}2.31,\;96.26{\pm}2.20$deg/sec). 5. Each displacement left, right of knee-joint showed maximal extent conditions by phase 1, 3, 4($173.46{\pm}2.95,\;171.51{\pm}5.44$deg/sec, $172.24{\pm}4.49,\;171.26{\pm}0.65$deg/sec, $162.78{\pm}2.13,\;164.10{\pm}5.97$deg/sec) but It showed flexion only left of knee-joint by phase 2($164.45{\pm}7.51,\;159.38{\pm}3.48$deg/sec). 6. Each speed left, right of the tip of the toes showed most fastest when someone jumped with lift up leges by phase 1, 2($321.32{\pm}67.91,\;316.90{\pm}41.97$cm/sec, $410.06{\pm}153.06,\;399.77{\pm}189.34$cm/sec), It showed more less speed than phase 1,2 by phase 3($169.74{\pm}67.17,\;150.00{\pm}63.80$cm/sec) and It showed most slow speed than phase 1,2,3 by phase 4($87.22{\pm}34.90,\;85.72{\pm}52.23$cm/sec).

• Journal of the Korean Ceramic Society
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• v.33 no.12
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• pp.1325-1330
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• 1996

A new numerical method for determining the surface tension of a liquid drop by experimental measurement of the contour of the sessile drop is explained. in the present method a very simple and short computer program enables the calculation of surface tension in a few seconds even by a low speed personal computer. It need not the use of any other numerical tables or complex techniques. X and Z-corrdinates at one point on the contour of a sessile drop and the tangential angle at that point are all the data needed when the density of the drop is known. The results were compared with the values derived by a conventional method. This method can be used for the confirmation of measuring accuracy. Also the same concepts can be applied for the pendant drop method by changing only the sign of Z-coordinate from "+" to "-"ot; to "-"ot;-"quot.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.26 no.4
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• pp.181-192
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• 2014

Light-shelf is one of the most efficient natural lighting systems due to the improved function of the inflow level of the outdoor natural light. However, the existing research on the light shelf limits to the rectangular parallelepiped space, so do not provide sufficient data for various shapes of spaces. Thus, this study aims at deriving proper plan and relationship of the light shelf through its performance assessment depending on the indoor space shapes and utilizing them as basic data of light shelf design. The conclusions are as follows : 1) for 6m space depth, standard intensity of illumination satisfaction depth has shown 8.3%~26.3% improvement through the adjustment of the angle and width when installing light shelf compared to no light shelf installation; 2) $-30^{\circ}$, $-20^{\circ}$ and $-10^{\circ}$ light shelves set by this study play only as a blind regardless of the shape of ceiling on the summer solstice, and it is unsuitable; and 3) this study has derived proper plan of light shelf upon space shapes based on energy reduction and indoor evenness. The study results provide expanded data of the performance assessment of the light shelves according to the different space shapes and light shelf factors, which serves as a basis of the light shelves designing.

• Journal of the Korea Society of Computer and Information
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• v.23 no.11
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• pp.111-122
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• 2018

The purpose of this study was to investigate the bodice prototype method suitable for the upper body shape of old-old aged women using the 3D anthropometric data. And it was to provide the basic data for the upper body garments of old-old aged women. In the overall appearance evaluation, the B pattern was rated as 4.00, and it was evaluated as the most suitable for the bodice prototype of the old-old aged woman. The E pattern was rated lower than normal, and the L pattern and the S pattern were found to be inadequate for older female bodice prototypes. As a result of the measurement of the waist and bust air gap of bodice prototype, the air gap of the bust was not significantly different between the patterns. But the waist air gap showed the largest difference between the L pattern and the S pattern. As a result of evaluating the appearance, the amount of space in the state of 3D simulation, and the air gap, the pattern B appeared to be the most appropriate prototype for the old-old aged women's body shape. However, there is a tendency that the shoulder end point is biased toward the back, so it is necessary to set the inclination of the back shoulder line to be more gentle. Conversely, the front shoulder should be more inclined. In the case of the 3D simulation, the B pattern showed that the other parts generally fit well. In the case of the 3D simulation program used in this study, it was evaluated that it is suitable only for the normal body shape because it is impossible to set the isometric angle which is one of the characteristics of the older female body shape. A study on the bodice prototype suitable for the bent body shape should be carried out through experiments on the actual body shape of various elderly women. In order to cope with the increase of elderly people who are familiar with digital, I think it is necessary to develop an avatar that reflects the old female body shape.