• Journal of the Korean earth science society
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• v.36 no.5
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• pp.437-446
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• 2015

Many edge detection methods, based on horizontal and vertical derivatives, have been introduced to provide us with intuitive information about the horizontal distribution of a subsurface anomalous body. Understanding the characteristics of each edge detection method is important for selecting an optimized method. In order to compare the characteristics of the individual methods, this study applied each method to synthetic magnetic data created using homogeneous prisms with different sizes, the numbers of bodies, and spacings between them. Seven edge detection methods were comprehensively and quantitatively analyzed: the total horizontal derivative (HD), the vertical derivative (VD), the 3D analytic signal (AS), the title derivative (TD), the theta map (TM), the horizontal derivative of tilt angle (HTD), and the normalized total horizontal derivative (NHD). HD and VD showed average good performance for a single-body model, but failed to detect multiple bodies. AS traced the edge for a single-body model comparatively well, but it was unable to detect an angulated corner and multiple bodies at the same time. TD and TM performed well in delineating the edges of shallower and larger bodies, but they showed relatively poor performance for deeper and smaller bodies. In contrast, they had a significant advantage in detecting the edges of multiple bodies. HTD showed poor performance in tracing close bodies since it was sensitive to an interference effect. NHD showed great performance under an appropriate window.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.13 no.3
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• pp.204-215
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• 1988

This paper deals with the adaptive state estimation which is designed specially for a tracking system containing unknown and/or radomly varying hybride noises to provide an accurate estimate of the system state. The range of discrete vectyor v in finite numbers(N) for this adaptive estimator span the entire possible range of impulse noise levels such as the binomial, the edge, the Tchebyscheff, the binomal-edge and the Tchbyscheff-edge distribution. A feed forward path consisting of zero detector and data selector is incoporated with the conventional adaptive state estimator so as to provide accurate estimations. Despite the large and randomly varying hybrid noises, results of computer simulations for the various discrete vector levels show that this adptive state estimator is turned out to be a good system with relatively small implse errors.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.7
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• pp.3329-3350
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• 2017

Installing caching and computing facilities in mobile edge networks is a promising solution to cope with the challenging capacity and delay requirements imposed on future mobile communication systems. The problem of optimal facility placement in mobile edge networks has not been fully studied in the literature. This is a non-trivial problem because the mobile edge network has a unidirectional topology, making existing solutions inapplicable. This paper considers the problem of optimal placement of a fixed number of facilities in a mobile edge network with an arbitrary tree topology and an arbitrary demand distribution. A low-complexity sequential algorithm is proposed and proved to be convergent and optimal in some cases. The complexity of the algorithm is shown to be $O(H^2{\gamma})$, where H is the height of the tree and ${\gamma}$ is the number of facilities. Simulation results confirm that the proposed algorithm is effective in producing near-optimal solutions.

• Journal of Broadcast Engineering
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• v.5 no.1
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• pp.31-40
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• 2000

In this paper, we propose an edge histogram to efficiently represent the edge distribution in the image for MPEG-7. To this end, we adopt global, semi-global, and local edge histogram bins. Also, we extract the edge information from the image in terms of image blocks rather than pixels, which reduces the extraction complexity and is also applicable to the block-based compression standards such as MPEG-1, and 2. Experimental results show that the proposed method yields better retrieval accuracy and feature extraction speed comparing to other non-homogeneous texture descriptors of MPEG-7 including the wavelet-based descriptor and local edge-based descriptor.

• Proceedings of the IEEK Conference
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• 2005.11a
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• pp.987-990
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• 2005

An important issue in the field of face recognitions and man-machine interfaces is an automatic detection of faces in visual scenes. it should be computationally fast enough to allow an online detection. In this paper we describe our ongoing work on face detection that models the face appearance by edge orientation and color distribution. We show that edge orientation is a powerful feature to describe objects like faces. We present a method for face region detection using edge orientation and a method for face feature detection using local color information. We demonstrate the capability of our detection method on an image database of 1877 images taken from more than 700 people. The variations in head size, lighting and background are considerable, and all images are taken using low-end cameras. Experimental results show that the proposed scheme achieves 94% detection rate with a resonable amount of computation time.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1997.04a
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• pp.323-325
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• 1997

Conventionally it is asummed that the microstrip line conductor has a rectangular cross-section. but the additive and substactive processes used to create conductors for PCBs produce a conductor of approximately Trapezoidal cross-section. For wide Strip line, the thickness and edge effect will be small since most of capacitance is parallel plate rather than fringing and we can ignore the cross-section. For narrow strip lines, the edge effect become immportant. So in this paper, we measure the chracteristic impedance of microstripline by Vector Analyzer and simulate the electromagnetic field of microstripline using finite element method with edge angle.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.11 no.6
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• pp.388-395
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• 1986

Dispersion characteristics of shielded single, coupled and edge-offset microstrip structures are investigated by using hybrid mode analysis with Galerkin's method in the spectral domain. Two new basis functions for the longitudinal strip current are proposed and convergence rates of the solutions for the basis functions are compared. Current distribution of the coupled line is obtaind from that of the single line by using shift theorem of the Fourier transform. In addition, effects of off-centered inner strip conductor on dispersion are also discussed Numerical results include various structual parameters and are compared with other available data and good agreements are observed.

• Proceedings of the KIEE Conference
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• 1999.11d
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• pp.1117-1119
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• 1999

An edge finite element method is applied to calculate the field distribution of a coupled waveguide structure. We compares a node based finite element method with the edge element one. For 2-d eigenvalue problems of waveguide structures, the former generates spurious eigenmodes, but the latter dose not. Using an simple rectangular waveguide, we implement both methods to obtain some results of field computation in waveguide. The paper shows that the finite element method using edge elements succeeds in suppressing spurious solutions.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2014.10a
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• pp.792-794
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• 2014

Character recognition is an image processing technique for obtaining the character information such as documents and automobile license plate and for this edge detection methods are commonly used. The previous edge detection methods are mostly applying the weighted value mask on the image and because it applies the same mask to the entire areas of the image, the processing results are somewhat insufficient. Therefore, this paper has proposed an edge detection algorithm by applying the weighted value mask considering the distribution and location of pixels to be suitable for the character recognition.

• Journal of the Korea Society of Computer and Information
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• v.12 no.3
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• pp.105-113
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• 2007

In this paper, an image segmentation method which is based on edge salience map and region merging is presented. The edge salience map is calculated by combining a texture edge map with a color edge map. The texture edge map is computed over multiple spatial orientations and frequencies by using Gabor filter. A color edge is computed over the H component of the HSI color model. Then the Watershed transformation technique is applied to the edge salience map to and homogeneous regions where the dissimilarity of color and texture distribution is relatively low. The Watershed transformation tends to over-segment images. To merge the over-segmented regions, first of all, morphological operation is applied to the edge salience map to enhance a contrast of it and also to find mark regions. Then the region characteristics, a Gabor texture vector and a mean color, in the segmented regions is defined and regions that have the similar characteristics, are merged. Experimental results have demonstrated the superiority in segmentation results for various images.