• Journal of Korea Water Resources Association
• /
• v.53 no.1
• /
• pp.29-43
• /
• 2020

The purpose of this study is to propose the design criteria and detailed design model by reviewing the issues related to geometry, formation process, destruction process, hydraulic function, restoration and ecological function of the step-pool from the existing research results, to apply the step-pool sequences to river restoration. Based on the analysis and review results, the design criteria for the structure and size of the step-pool are presented as ratio of the step spacing and the channel width, ratio of the unit step slope and channel slope, and ratio of step height and the particle size. To ensure structural stability of the step, stability analysis method of overturning based on the keystone theory was proposed as a design criterion. As a detailed design concept, a layout model was proposed by applying the imbricating structure of keystones and arch stones to the planar, longitudinal and transverse configurations of the step-pool.

• Journal of the Korean Geosynthetics Society
• /
• v.7 no.4
• /
• pp.25-36
• /
• 2008

This paper presents the results of numerical investigation on support mechanism of geogrid-encased stone columns for use in soft ground. A number of cases were analyzed using a axial-and 3D stress-pore pressure coupled model that can effectively model construction sequence and drainage as well as reinforcing effects of geogrid-encased stone columns. The results indicated that the geogrid encasement tends to significantly improve the load carrying of a stone column. Also revealed was that such a confinement effect depends on encasement length and stiffness of geogrid. It is also shown that there exist critical encasement length and stiffness of geogrid for a given condition.

• Communications of Mathematical Education
• /
• v.28 no.2
• /
• pp.219-234
• /
• 2014

Music and mathematics have a lot of structural similarities. Major and minor triads used importantly in music are in a relationship of inversion in which the sequence of the intervals is reversed, which is equivalent to reflection in mathematics. Geometrical expressions help understand structures in music as well as mathematics, and a diagram that shows tonal relationships in music is called Tonnetz. Relationships of reflection between major and minor triads can easily be understood by using Tonnetz, and also, transpositions can be expressed in translation. This study looks into existing Tonnetz and introduces S-Tonnetz newly formed by a mathematical principle.

• Journal of KIISE:Computing Practices and Letters
• /
• v.14 no.6
• /
• pp.559-566
• /
• 2008

In this paper, we propose a range subsequence matching under dynamic time warping (DTW) distance. We exploit Dual Match, which divides data sequences into disjoint windows and the query sequence into sliding windows. However, Dual Match is known to work under Euclidean distance. We argue that Euclidean distance is a fragile distance, and thus, DTW should be supported by Dual Match. For this purpose, we derive a new important theorem showing the correctness of our approach and provide a detailed algorithm using the theorem. Extensive experimental results show that our range subsequence matching performs much better than the sequential scan algorithm.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.28 no.11B
• /
• pp.999-1006
• /
• 2003

In the paper, we investigate the impact of handoff on the packet delivery in the Mobile IPv6 networks, where the smooth handoff is adopted. That is measured by an 'unstable time period (UTP)', a 'silence time period(STP)', and a 'handoff time period (HTP)' in the mobile node's perspective. Then, we propose a queuing model to get the exact value of the handoff transient time. The numerical results show that the queuing delay for the handoff packets and the involved link (or route) capacities affect the estimated UTP, STP, and HTP. On the other hand, the damage of application caused by handoff will increases when the handoff transient time becomes longer. We show that the priority scheduling method can achieve shorter STP and UP than the FIFO scheduling method that is generally used in best-effort IP network.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.10 no.3
• /
• pp.395-402
• /
• 2015

In this paper, we propose an efficient gait trajectory generation method for the static stair climbing of a quadruped robot with mechanism of insectile legs, which has no collision with staris. First, we derive the kinematic and inverse models of a quadruped robot using the algebraic and geometrical methods, respectively. In the proposed method, we generate the stair locomotion trajectory of a sine wave after lifting a leg from the start position, and then determine the coefficient of the generated trajectory to avoid the collision with stairs. In addition, we make the gait sequence for the stable stair locomotion. Finally, we verify the effectiveness and applicability of the proposed stair locomotion method through computer simulations.

• The Journal of the Korea Contents Association
• /
• v.9 no.6
• /
• pp.336-343
• /
• 2009

Companies often use database for performing task more efficiently and data mining for marketing and production efficiency through analyzing of the stored database. The use of the knowledge through the data mining maintains and provides a direction of development for the company. It could be as an additional competitive power for the company when decision making is necessary. This study is designing a model that predicts a rating of existing customer and consumption pattern with using actual data of the manufacturer and data mining methodology. The objective of this model is to improve profits for the company and brand value through connecting the marketing with identifying the customer's rating and consumer behavior.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2010.10a
• /
• pp.397-400
• /
• 2010

The changing light condition of scene cause the luminance fluctuation of the captured image sequences. this artifact is called flicker, and would be easily recognized as visually unstable fluctuation. As the flicker degrades the performance of extracting useful information from image sequences, such as motion information or segmentation, it should be correction and linear flicker model. The algorithm model the flicker effects as a linear system with gain and offset parameter and estimates gain parameter with Gamma correction. The flicker reduction is performed by applying these parameters inversely th the ordinal sequences. To show the performance, we test out algorithm th the ground-truth sequences with the artificially added luminance fluctuation and real sequence with object motion.

• Composites Research
• /
• v.36 no.1
• /
• pp.53-58
• /
• 2023

The PIC design method is assigning different stacking sequences for each shell element through the preliminary FE analysis. In previous study, machine learning was applied to the PIC design method in order to assign the region efficiently, and the training data is labeled by dividing each region into tension, compression, and shear through the preliminary FE analysis results value. However, since buckling is not considered, when buckling occurs, it can't be divided into appropriate loading type. In the present study, it was proposed PIC-NTL (PIC design using novel technique for analyzing load type) which is method for applying a novel technique for analyzing load type considering buckling to the conventional PIC design. The stress triaxiality for each ply were analyzed for buckling analysis, and the representative loading type was designated through the determined loading type within decision area divided into two regions of the same size in the thickness direction of the elements. The input value of the training data and label consisted in coordination of element and representative loading type of each decision area, respectively. A machine learning model was trained through the training data, and the hyperparameters that affect the performance of the machine learning model were tuned to optimal values through Bayesian algorithm. Among the tuned machine learning models, the SVM model showed the highest performance. Most effective stacking sequence were mapped into PIC tube based on trained SVM model. FE analysis results show the design method proposed in this study has superior external loading resistance and energy absorption compared to previous study.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.16 no.9
• /
• pp.1947-1954
• /
• 2012

The first frame is encoded in intra mode which generates a larger number of bits. In addition, the first frame is used for the inter mode encoding of the following frames. Thus the initial QP for the first frame affects the first frame as well as the following frames. Traditionally, the initial QP is determined among four constant values only depending on the bpp. In the case of low bit rate video coding, the initial QP value is fixed to 40 regardless of the output bandwidth. Although this initialization scheme is simple, yet it is not accurate enough. An accurate initial QP prediction scheme should not only depends on bpp but also on the complexity of the video sequence and the output bandwidth. In the proposed scheme, we determine the initial QP according to the ratio of the first frame to the total bits allocated to a GOP. To estimate the QP of the allocated bits, Rate-QP model is used. It is shown by experimental results that the new algorithm can predict the optimal initial QP more accurately and generate the PSNR performance better than that of the existing JVT algorithm.