• The korean journal of orthodontics
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• v.32 no.4 s.93
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• pp.275-291
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• 2002

Of various factors indicated for effective use of straight wire appliances, there was a great lack of studies both domestic and international about the curvatures of tooth crowns. This study was performed to investigate the labio/buccal clinical crown curvatures of Korean permanent teeth. For this study, three-dimensional laser scanning was performed on 36 dental casts with normal anatomic structures. Andrews plane and Facial axis of clinical crown (FACC) were designated as horizontal and vertical reference planes respectively. 2 or 3 lines, 1mm apart, were drawn superior, inferior, left and right of these reference planes. A three-dimensional coordinate table was made for points formed by crossing these lines, and averages of each coordinate point on the 36 dental casts were obtained. The curvature equation was made using three-dimensional coordinate points (x,y,z) and by this curvature equation, the curve ratio of each tooth was obtained. Curve ratio changes of each section of teeth were calculated by curve ratios of simplified curves. These two dimensional curves were simplified horizontally and vertically Conclusions for this study are as follows. 1. The basic data of labial and buccal clinical crown curvatures were obtained about Korean permanent teeth. 2. No significant difference was found between male and females. 3. Individual tooth characteristics 1) In maxillary central incisors, the difference in the curve ratio between the gingival and incisal sides was greater than for the other teeth. And the gingival side showed a greater curve ratio. 2) Maxillary canines showed more curvatures in the mesio-occlusal surface than the other surfaces. 3) In maxillary $1^{st}$ premolars, more curvatures were found in mesio-occlusal and disto-gingival surface, thus showing a twisted crown surface, but in maxillary $2^{nd}$ premolars, the crown curvatures of mesial and distal ends became parallel to each other. 4) No significant difference in crown curvatures was found between mandibular central and lateral incisors. 5) Occluso-gingival curvatures of mandibular$2^{nd}$ premolar turned out to be more rounded than mandibular $1^{st}$ premolars or maxillary $2^{nd}$ premolars. From the above conclusions, it can be deduced that the same bracket bases can be used for mandibular central and lateral incisors. But for maxillary $1^{st}\;and\;2^{nd}$ premolars and for mandibular $1^{st}\;and\;2^{nd}$ premolars, because crown curvatures showed significant differences, when making bracket bases there is ample reason to make bracket base curves differently for each type of tooth.

• Radiation Oncology Journal
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• v.10 no.2
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• pp.137-145
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• 1992

Three-dimensional dose calculations based on CT images are fundamental to stereotactic radiosurgery for small intracranial tumor. In our stereotactic radiosurgery program, irradiations have been performed using the 6 MV photon beam of linear accelerator after stereotactic CT investigations of the target center through the beam's-eye view and the coordinates of BRW frame converted to that of radiosurgery. Also we can describe the tumor diameter and the shape in three dimensional configuration. Non-coplanar irradiation technique was developed that it consists of a combination of a moving field with a gantry angle of $140^{\circ}$, and a horizontal couch angle of $200^{\circ}C$ around the isocenter. In this radiosurgery technique, we provide the patient head setup in the base-ring holder and rotate around body axis. The total gantry moving range shows angle of 2520 degrees via two different types of gantry movement in a plane perpendicular to the axis of patient. The 3-D isodose curves overlapped to the tumor contours in screen and analytic dose profiles in calculation area were provided to calculate the thickness of $80\%$ of tumor center dose to $20\%$ of that. Furtheremore we provided the 3-D dose profiles in entire calculation plane. In this experiments, measured isodose curves in phantom irradiation have shown very similiar to that of computer generations.

• The korean journal of orthodontics
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• v.25 no.2 s.49
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• pp.153-163
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• 1995

In this study, Receiver Operating Characteristic(ROC) analysis was used to evaluate the ability of cephalometric measurements to identify patients with Class III malocclusions. ROC analysis is the method for determining the validity of a diagnostic measure and for evaluating the relative value of diagnostic tests. The sample consisted of 496 patients with malocclusion. Class III malocclusion is defined as the dental relationship for which The mesiobuccal groove of the lower first molar is deviated mesially from the mesiobuccal cusp of the upper first molar. Of the total sample of 496 patients, 245 had Class III malocclusions. 16 cephalometric measurements were selected, each of which was treated as a diagnostic test. The ROC curves were generated for each cephalometric measurement with intervals of $1.0^{\circ}$ for angular measurements, 1.0mm for linear measurements. The area under the ROC curves was measured for direct comparison among different diagnostic tests. The results were as follows; 1. The 'Wits' appraisal was found to be a better diagnostic criterion for the presence of Class III malocclusion than any other commonly'used cephalometric measurement. 2. AB plane angle, ANB angle, App-Bpp distance, AF-BF distance, APDI, Distance of point A and Pog to N perpendicular, maxillomandibular differential had high diagnostic value. 3. Cephalometric measurements which evaluate the position of the mandible had moderate diagnostic value. 4. Cephalometric measurements related to the maxilla discriminated least between patients with and without Class III malocclusion.

• Journal of Korean Association for Spatial Structures
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• v.12 no.1
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• pp.109-119
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• 2012

For membrane structure, there are three main steps in design and construction, which are form finding, statistical load analysis, and cutting patterning. Unlike the first two stages, the step of cutting pattern involves the translation of a double-curved surface in 3D space into a 2D plane with minimal error. For economic reasons, the seam lines of generated cutting patterns rely greatly on the geodesic line. Generally, as searching regions of the seam line are plane elements in the step of shape analysis, the seam line is not a smooth curve, but an irregularly divided straight line. So, it is how we make an irregularly divided straight line a smooth curve that defines the quality of the pattern. Accordingly, in this paper, we analyzed interpolation schemes using spline, and apply these methods to cutting pattern generation on the curved surface. To generate the pattern, three types of spline functions were used, i.e., cubic spline function, B-spline, and least-square spline approximation, and simple model and the catenary-shaped membrane was adopted to examine the result of generation. The result of comparing the approximation curves by the number of elements and the number of extracted nodes of simple model revealed that the seam line for less number of extracted nodes with large number of elements were more efficient, and the least-square spline approximation provided smoother seam line than other methods.

• 한국태양에너지학회:학술대회논문집
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• 2012.03a
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• pp.457-462
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• 2012

Daylighting software is an important component to predict the performance of daylighting system in advance of a field demonstration study with installing them in buildings. PHOTOPIA is a powerful software to generate a candela distribution curve(CDC) of an active daylighting system like a tracking dish concentrator. With PHOTOPIA, a set of candela distribution curves was generated under clear sky conditions and different solar altitude angles. The candela distribution curves were then imported to RADIANCE for rendering and analysis on the daylighting performance of a tracking dish concentrator when it installed in a actual class room without windows. As a result, the daylight collection efficiency of the dish concentrator was 68.4% when we assumed that there was no tracking error. It was found that candela(cd) and total lumens(lm) increased with solar altitude rising, whereas the distribution angle was fixed. The illuminance uniformity on the work plane in the class room was relatively low, 0.12, while the illuminance uniformity on the area of $2.7m^2$ to which the light was illuminated was considerably high, 0.60. The maximum illuminance was 1,340lux with a solar altitude angle of 80 degrees.

• Journal of the Korea Society of Computer and Information
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• v.16 no.9
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• pp.27-33
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• 2011

In this paper, we propose an efficient on-line handwritten digit recognition base on Convex-Concave curves feature which is extracted by a chain code sequence using Smith-Waterman alignment algorithm. The time sequential signal from mouse movement on the writing pad is described as a sequence of consecutive points on the x-y plane. So, we can create data-set which are successive and time-sequential pixel position data by preprocessing. Data preprocessed is used for Convex-Concave curves feature extraction. This feature is scale-, translation-, and rotation-invariant. The extracted specific feature is fed to a Smith-Waterman alignment algorithm, which in turn classifies it as one of the nine digits. In comparison with backpropagation neural network, Smith-Waterman alignment has the more outstanding performance.

• Journal of Korean Society of Steel Construction
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• v.10 no.4 s.37
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• pp.779-788
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• 1998

This paper presents the results of the experimental and analytical investigation for the fatigue strength of welded details frequently used in steel bridges, especially for the details with relatively lower fatigue strength. Considering the measured stress fatigue cracking initiated at toe of the transverse fillet weld joining the gusset plates to the web because of the stress concentration that developed as a result of the geometric conditions and the greater probability of microscopic discontinuities at the fillet weld toe A comparison was made of the stress calculated by considering geometric aspect of bead and measured at same position. They indicate that the geometric conditions of the weld toe result in similar stress concentration on both FEM models and test results. The test results were compared with the fatigue criteria of AASHTO, JSSC specifications. Specimens of 80 and 150mm gusset plate configuration tested either respectively equaled or exceeded the fatigue resistance provided by category D and E of the AASHTO specification. It also satisfied the category F and G of JSSC. Both WG1 and WG3 specimen tend to provide S-N curves with a store near -0.3 less than AASHTO and JSSC.

• Progress in Superconductivity
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• v.9 no.1
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• pp.5-10
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• 2007

We prepared four different $MgB_2$ films on $Al_2O_3$ by hybrid physical chemical vapor deposition method with thicknesses ranging from $0.65\;{\mu}m$ to $1.2\;{\mu}m$. X-ray diffraction patterns confirm that all the $MgB_2$ films are c-axis oriented perpendicular to $Al_2O_3$ substrates. The superconducting onset temperature of $MgB_2$ films were between 39.39K and 40.72K. The residual resistivity ratio of the $MgB_2$ films was in the range between 3.13 and 37.3. We measured the angle dependence of critical current density ($J_c$) and resistivity, and determined the upper critical field ($H_{c2}$) from the temperature dependence of the resistivity curves. The anisotropy ratios defined as the ratio of the $H_{c2}$ parallel to the ab-plane to that perpendicular to the ab-plane were in the range of 2.13 to 4.5 and were increased as the temperature was decreased. Some samples showed increase of $J_c$ and decrease of resistivity when a magnetic field in applied parallel to the c-axis. We interpret this angle dependence in terms of enhanced flux pinning due to columnar growth of $MgB_2$ along the c-axis.

• Journal of Ocean Engineering and Technology
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• v.23 no.5
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• pp.71-78
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• 2009

In ship design or offshore structure design, the evaluation of buckling strength (or ultimate strength) is critical to the determination of scantling of stiffened plates. For this reason, it is useful to study the effect of applying different formula or the relationship between stiffened plate with buckling utilization factor (UF). It can facilitate a designer to decide how much the scantling should be reinforced or how much can be reduced for an optimal design. This paper conducts a comparative study for three buckling check methods; DNV-Ship-Rule, DNV-RP-C201, DNV-PULS. The capacity curves and 2D contour plot for utilization factors versus bi-axial in-plane stresses are compared. The contour plots of DNV-Ship-Rule and DNV-PULS show smoothly increasing trends of UF as the applied in-plane stresses increase, however that of DNV-RP-C201 shows rapidly increasing trend as the applied stresses go beyond transverse buckling stress. A sensitivity analysis is performed to investigate the influence level of each parameter of a stiffened plate on UF. Resulting from the analysis, plate thickness is identified to be the most affective parameter to UF regardless of the buckling check methods. Based on the addressed study, optimal designs for bottom plate of 165 K tanker corresponding to three formulas are compared with each other. DNV-PULS yields 1 mm and 2 mm less thickness than DNV-Ship-Rule and DNV-RP-C201, respectively.

• The Korean Fashion and Textile Research Journal
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• v.10 no.5
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• pp.652-659
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• 2008

This study was designed to testify the possibility and devise the method to manipulate the 3D body scan data to produce rounded-belt pattern adaptable to hip-type variation of women in their 20's. The results of this research were as follows : Firstly, based on drop-value distribution of hip and waist girth, 151 subjects were classified into three hip-types; Type 1 (15.23%) was 'cylinder type', showing lowest drop-value, Type 2 (69.54%) was 'average type' and Type3 (15.23%) was 'hourglass type' showing highest drop-value. Secondly, using CAD program, design lines for round shape belt were set on the surface of 3D scan data of representative subject of each type. And divided 3D surfaces were flattened onto the plane by the internal tools of CAD program. The measure, 'lifting value of round belt pattern', implying the level of curve ratio of pattern was higher in back than front. This result might be linked to the fact that the hip part is more protruded than the abdomen part. And the measures also showed highest values in Type 3(hourglass type) and lowest in Type 1(cylinder type), meaning that the pattern of Type 3 showed more rounded shape than that of Type 1. This finding implied that round belt for body type having high drop-value should be shaped more curved. Thirdly, difference ratios of outline length and area between 3D curves(body surface) and 2D plane(pattern) were 4.5% and 1.3%, respectively. This result demonstrated and solidified the feasibility of designing digital garment pattern from 3D body scan data.