• The Journal of Churna Manual Medicine for Spine and Nerves
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• v.6 no.2
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• pp.121-132
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• 2011

Objectives : The purpose of this study is to investigate the cervical spine curvature after whiplash injury by traffic accident. Methods : The cervical lateral radiographs of 102 outpatients who visited emergency room in Kyung-Hee university hospital at Gangdong after whiplash injury by road traffic accident were reviewed to measure the cervical spine angle using C1-7, C2-7 Cobb method, Sagittal tangent method, Jochumsen method and the Ishihara index by two oriental medical doctors. For statistics, we used SPSS version 17.0 for windows. Results : Means of cervical angle are $37.63{\pm}11.34^{\circ}$, $12.92{\pm}9.13^{\circ}$, $16.19{\pm}10.62^{\circ}$, $1.78{\pm}3.37$ and $8.51{\pm}9.78$ by C1-C7 Cobb Method, C2-C7 Cobb Method, Sagittal tangent method, Jochumsen method and Ishihara index, respectively. Hypolordosis is most numeral in patients by C1-C7 Cobb Method(n=40; 39.22%), Sagittal tangent method(n=68; 66.67%). And Straight is the most by Jochumsen method(n=54; 52.94%), but Normal is the most by Ishihara index(n=53; 51.96%). And Female has smaller curvature in cervical spine than male significantly by C2-C7 Cobb method and Sagittal tangent method(P<0.05). Conclusions : Whiplash injury tends to make hypolordosis or straight. And female has more vulnerable curvature than male in whiplash injury.

• The Journal of the Acoustical Society of Korea
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• v.43 no.3
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• pp.324-334
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• 2024

The Wavefront Curvature Ranging (WCR) is an estimation method for a source range from the wavefront curvature of acoustic waves. The conventional method uses trigonometry to estimate the source range by assuming the sound speed as a constant. Because of this assumption, range error occurs in the ocean environment where the bottom reflection is clearly separated. In order to reduce the range error, Matched Wavefront Curvature Ranging (MWCR) was proposed applying the sound speed structure in the ocean environment and Maximum Likelihood Estimation (MLE). The range error was reduced in the results of the simulation on the proposed method. In the future, this method will be applicable to the sonar system if the reliability of ranging is confirmed by measured signal.

• Journal of Korean Medicine Rehabilitation
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• v.20 no.1
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• pp.133-139
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• 2010

Objectives : The purpose of this study was to compare about quantity of pain and fatigue according to cervical spine curvature of patient with neck pain. Methods : Cervical spine curvature was measured using the sagittal radiography of the cervical spine, neck pain was evaluated using the VAS and neck fatigue was evaluated using fatigue symptom checklist. Based on four line Cobb's method, 51 subjects were divided into hypolordosis group, normal group, hyperlordosis group. Window version SPSS 12K was used for statistical analysis about relation between pain and cervical spine curvature of each group, also about between fatigue and cervical spine curvature of each group. Results : 1. A significant difference was not found between pain and cervical curvature of each group. 2. A significant difference was not found between fatigue and cervical curvature of each group. Conclusions : There was no relation between pain and cervical curvature of each group, also fatigue and cervical curvature.

• Proceedings of the IEEK Conference
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• 2003.11a
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• pp.505-508
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• 2003

The current paper proposes a new vertex selection scheme for polygon-based contour ceding. To efficiently characterize the shape of an object, we incorporate the curvature information in addition to the conventional maximum distance criterion in vertex selection process. The proposed method consists of “two-step procedure.” At first, contour pixels of high curvature value are selected as key vertices based on the curvature scale space (CSS), thereby dividing an overall contour into several contour-segments. Each segment is considered as an open contour whose end points are two consecutive key vertices and is processed independently. In the second step, vertices for each contour segment are selected using progressive vertex selection (PVS) method in order to obtain minimum number of vertices under the given maximum distance criterion ( $D_{MAX}$). Experimental results are presented to compare the approximation performances of the proposed and conventional methods.s.

• Current Optics and Photonics
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• v.1 no.4
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• pp.378-388
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• 2017

We present a graphical method for determining a pair of optical materials and powers to design an achromatic and athermal lens system with corrected Petzval curvature. To graphically obtain the solutions, a three-dimensional (3D) glass chart is proposed. Even if a particular material combination is unavailable, we can select an element suitable for a specific lens and continuously change the element powers of an equivalent single lens for aberrations correction. Thus, we can iteratively identify the materials and powers on a 3D glass chart. By designing a fisheye lens using this method, an achromatic and athermal system with flat Petzval curvature is obtained, over the specified waveband and temperature ranges.

• Honam Mathematical Journal
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• v.28 no.2
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• pp.233-240
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• 2006

In this paper, we consider the problem of achieving a prescribed scalar curvature on warped product manifolds according to fiber manifolds with constant scalar curvature.

• Journal of Mechanical Science and Technology
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• v.17 no.11
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• pp.1693-1703
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• 2003

This paper presents a new local obstacle avoidance method for indoor mobile robots. The method uses a new directional approach called the Lane Method. The Lane Method is combined with a velocity space method i.e., the Curvature-Velocity Method to form the Lane-Curvature Method (LCM). The Lane Method divides the work area into lanes, and then chooses the best lane to follow to optimize travel along a desired goal heading. A local heading is then calculated for entering and following the best lane, and CVM uses this local heading to determine the optimal translational and rotational velocities, considering some physical limitations and environmental constraint. By combining both the directional and velocity space methods, LCM yields safe collision-free motion as well as smooth motion taking the physical limitations of the robot motion into account.

• Proceedings of the KIEE Conference
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• 2003.11b
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• pp.19-22
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• 2003

This paper proposes an algorithm for navigation of an autonomous mobile robot with vision sensor. For obstacle avoidance, we used a curvature trajectory method. Using this method, translational and rotational speeds are controlled independently and the mobile robot traces a smooth curvature trajectory that consists of circle trajectories to a target point. While trying to avoid obstacles, the robot fan be goal-directed using curvature trajectory.

• 제어로봇시스템학회:학술대회논문집
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• 1988.10b
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• pp.786-789
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• 1988

Partially occluded objects are recognized from a 2-D image through the use of maximum curvature points on the image boundary. The vertices of high curvature on an occluded object are classified by the objects which are hypothesized to be involved in the occlusion. A heuristic method is developed for computational speed. Two typical examples are given to illustrate the accuracy as well as the simplicity of the heuristic method.

• Journal of the Korean Institute of Telematics and Electronics
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• v.24 no.6
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• pp.1020-1024
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• 1987

Image segmentation based on the curvature of bi-directiona distribution functions of histogram with no mode informations is proposed. The curvature is an oscillating function and can be approximated to a polynomial form with a least square method using the Chebyshev basis. Nonhomogeneous linea equations are solved by Gauss-elimination method. In the proposed algorithm, critical points of the curvature are obtained on each direction to compensate the segmentation parameters, which can be ignored in only one-directional histogram.