• The Korean Journal of Zoology
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• v.32 no.1
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• pp.14-21
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• 1989

Four external and 22 cranial characters of 279 specimens representing 24 species of six orders of Korean mammals were measured. The data were analyzed by phenetic methods such as ordination as well as clustering techniques. Morphological distances were also calculated. Phenetic studies yield taxonomic placements of Siberian mink, Palearetic squirrel, and big white-toothed shrew which are incorrect. Morphological differences among Korean mammals at ordinal level in the taxonomic hierarchy are larger than those among other mammals: morphological differences below ordinal level are comparable to those among other mammals. Average taxonomic distances and morphological differences among Korean mammals at various levels in the taxonomic hierarchy are jointly monotonic, although the value of Pearson's product-moment correlation coefficient between average taxonomic distance matrix and morphological difference marrix is 0.59.

• 제어로봇시스템학회:학술대회논문집
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• 1998.10a
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• pp.496-500
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• 1998

Not merely running at the designated constant speed as the classical cruise control, the adaptive cruise control (ACC) maintains safe headway distance when the front is blocked by other vehicles. One of the most essential part of ACC System is the range sensor which can measure the position and speed of all objects in front continuously, ignore all irrelevant objects, distinguish vehicles in different lanes and lock on to the closest vehicle in the same lane. In this paper, the hierarchical object recognition algorithm (HORA) is proposed to process raw scanning laser data and acquire valid distance to target vehicle. HORA contains two principal concepts. First, the concept of life quantifies the reliability of range data to filter off the spurious detection and preserve the missing target position. Second, the concept of conformation checks the mobility of each obstacle and tracks the position shift. To estimate and predict the vehicle position Kalman filter is used. Repeatedly updated covariance matrix determines the bound of valid data. The algorithm is emulated on computer and tested on-line with our ACC vehicle.

• Journal of Institute of Control, Robotics and Systems
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• v.12 no.6
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• pp.568-572
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• 2006

This paper presents the device of recognizing image of the studded paving blocks, transmitting, the information by vibration to a visually handicapped person. Usually the blind uses the walking stick to recognize the studded paving block. This research uses a PCA (Principal Component Analysis) based image processing approach for recognizing the paving blocks. We classify the studded paving blocks into 5 classes, that is, vertical line block, right-declined line block, left-declined line block, dotted block and flat block. The 8 images for each of 5 classes are captured for each block by 112*120 pixels, then the eigenvectors are obtained in magnitude order of eigenvectors by using principal component analysis. The principal components for images can be calculated using projection of transformation matrix composed of eigenvectors. The classification has been executed using Euclidean's distance, so the block having minimum distance with a image is chosen as matched one. The result of classification is transmitted to the blind by electric vibration signals with different magnitudes and frequencies.

• Journal of Communications and Networks
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• v.9 no.2
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• pp.159-166
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• 2007

In this paper, we propose an efficient and robust interference mitigation technique based on a nullsteering multi-user multiple-input multiple-output (MU-MIMO) spatial division multiple access (SDMA) scheme for frequency sharing between IMT-advanced and fixed satellite service (FSS) in the 3400-4200 and 4500-4800 MHz bands. In the proposed scheme, the pre-existing precoding matrix for SDMA unitary precoded (UPC) MIMO proposed by the authors is modified to construct nulls in the spatial spectrum corresponding to the direction angles of the victim FSS earth station (ES). Furthermore, a numerical formula to calculate the power of the interference signal received at the FSS ES when IMT-Advanced base stations (BS) are operated with the interference mitigation technique is presented. This formula can be derived in closed form and is simply implemented with the help of simulation, resulting in significantly reduced time to obtain the solution. Finally, the frequency sharing results are analyzed in the co-channel and adjacent channel with respect to minimum separation distance and direction of FSS earth station (DOE). Simulation results indicate that the proposed mitigation scheme is highly efficient in terms of reducing the separation distance as well as robust against DOE estimation errors.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.2
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• pp.927-939
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• 2015

It appears that the rapid advance in technology has allowed to broaden the variety of rail systems technology, thereby fostering new business opportunity in rail industry. The direction of rail systems operations is mainly two fold. In one direction, long distance operations between mega cities are pursued with help of high speed trains under development. In the other case, relatively short distance operations for covering intra-city or suburban area are becoming popular. A good example of the latter case is light rail transit (LRT) systems. Due to the short distance operation, it is thus expected that both the development and operation cost for LRT systems be reduced to some extent. The cost reduction desired in there can be gained by scaling down the sizes of both the trains and stations as compared to those of normal rail systems. However, it is not well known how the LRT stations can be scaled down. The objective of this paper is to study on how to slim down the stations (particularly, the functions room) of LRT systems. To achieve the objective, an approach is studied based on a modified method of design structure matrix (DSM). Specifically, using the enhanced DSM method, an integrated architecture is developed for the functions room, in which equipments are housed to perform the functions of electricity, signaling, and communication for LRT stations. The use of the result indicates that the desired reduction can be obtained with the approach taken in the paper.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.21 no.11
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• pp.1896-1911
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• 1997

Effects of fiber-matrix interphases on the micro-and macro-mechanical behaviors of unidirectionally fiber-reinforced composites subjected to transverse shear loading at remote distance have been studied. The interphases between fibers and matrix have been modeled by the spring-layer which accounts for continuity of tractions, but allows radial and circumferential displacement jumps across the interphase that are linearly related to the normal and tangential tractions. Numerical calculations for basic cells of the composites have been carried out using the boundary element method. For an undamaged composite the micro-level stresses at the matrix side of the interphase and effective shear stiffness have been computed as functions of fiber volume ratio $V_f$ and interphase stiffness k. Results are presented for various interphase stiffnesses from the perfect bonding to the case of total debonding. For a square array composite the results show that for a high interphase stiffness k>10, an increase of $V_f$ increases the effective transverse shear modulus G over bar of the composite. For a relatively low interphase stiffness k<1, it is shwon that an increase of $V_f$ slightly decreases the effective transverse shear modulus. For the perfect bonding case, G over bar for a hexagonal array composite is slightly larger than that for a square array composite. Also for a damaged composite partially debonded at the interphase, local stress fields and effective shear modulus are calculated and a decrease in G over bar has been observed.

• Journal of the Korean Institute of Telematics and Electronics
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• v.26 no.7
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• pp.166-175
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• 1989

In this paper, we present a method which is based on the concept of the rotation of subspaces. This method is highly related to the angle (or distance) between subspaces arising in many applications. An effective procedures is first derived for finding the optimal transformation matrix which rotates one subspace into another as closely as possible in the least squares sense , and then this algorithm is applied to the solution to general direction-of-arrival estimation problem of multiple broadband plane waves which may be a mixture of incoherent, partially coherent or coherent. In this typical application, the rotation of signal subspaces (ROSS) algorithm is effectively developed to achieve the high performance in the active systems for the case in which the noise field remains invariant with the measurement of the array spectral density matrix (or data matrix). It is not uncommon to observe this situation in sonar systems. The advantage of this techniques is not to require the preliminary processing and spatial prefiltering which is used in Wang-Kaveh's CSS focusing method. Furthermore, the array's geometry is not restricted. Simulation results are presented to illustrate the high performance achieved with this new approach relative to that obtained with Wang-Kaveh's CSS focusing method for incoherent sources and forward-backward spatial smoothed MUSIC for coherent sources including the signal eigenvector method (SEM).

• Journal of the Institute of Convergence Signal Processing
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• v.14 no.1
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• pp.45-50
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• 2013

Sensors have limited resources in sensor networks, so efficient use of energy is important. Representative clustering methods, LEACH, LEACHC, TEEN generally use direct transmission methods from cluster headers to a sink node to pass collected data. If clusters are located at a long distance from the sink node, the cluster headers exhaust a lot of energy in order to transfer the data. As a consequence, the life of sensors is shorten and re-clustering is needed. In the process of clustering, sensor nodes consume some energy and the energy depletion of the cluster headers meet another energy exhaustion. A method of transferring data from cluster headers to the sink using neighbor clusters is needed for saving energy. In this paper, we propose a novel routing method using a multi-hop transmission method in cluster sensor networks. This method uses the topology matrix which presents cluster topology. One-hop routing and two-hop routing are proposed in order to increase the energy efficiency.

• Journal of the Korean Institute of Intelligent Systems
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• v.19 no.5
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• pp.648-654
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• 2009

In this paper, a method called bilateral diagonal 2DLDA is proposed for face recognition. Two methods called Dia2DPCA and Dia2DLDA were suggested to reserve the correlations between the variations in the rows and columns of diagonal images. However, these methods work in the row direction of these images. A row-directional projection matrix can be obtained by calculating the between-class and within-class covariance matrices making an allowance for the column variation of alternative diagonal face images. In addition, column-directional projection matrix can be obtained by calculating the between-class and within-class covariance matrices making an allowance for the row variation in diagonal images. A bilateral projection scheme was applied using left and right multiplying projection matrices. As a result, the dimension of the feature matrix and computation time can be reduced. Experiments carried out on an ORL face database show that the proposed method with three different distance measures, namely, Frobenius, Yang and AMD, is more accurate than some methods, such as 2DPCA, B2DPCA, 2DLDA, etc.

• Communications of Mathematical Education
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• v.37 no.3
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• pp.443-465
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• 2023

This study examines the content of vectors and matrices in Artificial Intelligence Mathematics textbooks (AIMTs) from the 2015 revised mathematics curriculum. We analyzed the implementation of foundational mathematical concepts, specifically definitions and related sub-concepts of vectors and matrices, in these textbooks, given their importance for understanding AI. The findings reveal significant variations in the presentation of vector-related concepts, definitions, sub-concepts, and levels of contextual information and descriptions such as vector size, distance between vectors, and mathematical interpretation. While there are few discrepancies in the presentation of fundamental matrix concepts, differences emerge in the subtypes of matrices used and the matrix operations applied in image data processing across textbooks. There is also variation in how textbooks emphasize the interconnectedness of mathematics for explaining vector-related concepts versus the textbooks place more emphasis on AI-related knowledge than on mathematical concepts and principles. The implications for future curriculum development and textbook design are discussed, providing insights into improving AI mathematics education.