• 대한전기학회:학술대회논문집
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• 대한전기학회 1987년도 정기총회 및 창립40주년기념 학술대회 학회본부
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• pp.425-429
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• 1987

This paper describes a collision avoidance method for planning safe trajectories for multi-robot system in common work space. Usually objects have been approximated to convex polyhedra in most previous researches, but in case using such the approximation method it is difficult to represent objects analytically in terms of functions and also to describe tile relationship between the objects. In this paper, in order to solve such problems a modeling method which approximates objects to cylinder ended by hemispheres and or sphere is used and the maximum distance functions is defined which call be calculated simply. Using an objective function with inequality constraints which are related to minimum distance functions, work range and maximum allowable angular velocities of the robots, tile collision avoidance for two robots is formulated to a constrained function optimization problem. With a view to solve tile problem a penalty function having simple form is defined and used. A simple numerical example involving two PUMA-type robots is described.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2006년도 하계종합학술대회
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• pp.49-50
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• 2006

Digital satellite systems are usually integrated with terrestrial systems to provide various services, and in these cases they should satisfy the performance objectives defined by the terrestrial systems. Recommendation ITU-R S.1062 specifies the performance of digital satellite systems. The performance objectives were given in terms of bit error probability divided by the average number of errors per burst versus percentage of time. This paper presents theoretical method to estimate performance measure of digital satellite systems defined in Recommendation ITU-R S.1062. We show performance estimation results of duo-binary Turbo codes, and verify them by comparing to the simulation results.

• JSTS:Journal of Semiconductor Technology and Science
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• 제16권3호
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• pp.261-273
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• 2016

Reconfigurable finite impulse response (FIR) filters whose filter coefficients and filter order change dynamically during run-time play an important role in the software defined radio (SDR) systems, multi-channel filters, and digital up/down converters. However, there are not many reports on such reconfigurable designs which can support dynamic variation of filter order and filter coefficients. The purpose of this paper is to provide an architectural solution for the FIR filters to support run-time variation of the filter order and filter coefficients. First, two straightforward designs, namely, (i) single-MAC based design and (ii) full-parallel design are presented. For large variation of the filter order, two designs based on (iii) folded structure and (iv) fast FIR algorithm are presented. Finally, we propose (v) high throughput design which provides significant advantage in terms of hardware and/or time complexities over the other designs. We compare complexities of all the five structures, and provide the synthesis results for verification.

• Kyungpook Mathematical Journal
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• 제60권3호
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• pp.467-475
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• 2020

Let G be a chemical graph with vertex set {v₁, v₁, …, v_n} and degree sequence d(G) = (deg_G(v₁), deg_G(v₂), …, deg_G(v_n)). The inverse degree, R(G) of G is defined as $R(G)={\sum{_{i=1}^{n}}}\;{\frac{1}{deg_G(v_i)}}$. The cyclomatic number of G is defined as γ = m - n + k, where m, n and k are the number of edges, vertices and components of G, respectively. In this paper, some upper bounds on the diameter of a chemical graph in terms of its inverse degree are given. We also obtain an ordering of connected chemical graphs with respect to the inverse degree.

• Earthquakes and Structures
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• 제2권4호
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• pp.377-396
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• 2011

In seismic design and structural assessment using the displacement-based approach, real structures are simplified into equivalent single-degree-of-freedom systems with equivalent properties, namely period and damping. In this work, equations for the optimal pair of equivalent properties are derived using statistical procedures on equivalent linearization and defined in terms of the ductility ratio and initial period of vibration. The modified Clough hysteretic model and 30 artificial accelerograms, compatible with the acceleration spectra for firm and soft soils, defined by the Japanese Design Specifications for Highway Bridges are used in the analysis. The results obtained with the proposed equations are verified and their limitations are discussed.

• International Journal of Computer Science & Network Security
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• 제22권4호
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• pp.374-386
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• 2022

Nowadays, research in deep learning leveraged automated computing and networking paradigm evidenced rapid contributions in terms of Software Defined Networking (SDN) and its diverse security applications while handling cybercrimes. SDN plays a vital role in sniffing information related to network usage in large-scale data centers that simultaneously support an improved algorithm design for automated detection of network intrusions. Despite its security protocols, SDN is considered contradictory towards DDoS attacks (Distributed Denial of Service). Several research studies developed machine learning-based network intrusion detection systems addressing detection and mitigation of DDoS attacks in SDN-based networks due to dynamic changes in various features and behavioral patterns. Addressing this problem, this research study focuses on effectively designing a multistage hybrid and intelligent deep learning classifier based on modified deep forest classification to detect DDoS attacks in SDN networks. Experimental results depict that the performance accuracy of the proposed classifier is improved when evaluated with standard parameters.

• Korean Journal of Mathematics
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• 제31권1호
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• pp.109-120
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• 2023

The Berezin symbol à of an operator A on the reproducing kernel Hilbert space 𝓗 (Ω) over some set Ω with the reproducing kernel k_λ is defined by $${\tilde{A}}(\lambda)=\,\;{\lambda}{\in}{\Omega}$$. The Berezin number of an operator A is defined by $$ber(A):=\sup_{{\lambda}{\in}{\Omega}}{\mid}{\tilde{A}}({\lambda}){\mid}$$. We study some problems of operator theory by using this bounded function Ã, including estimates for Berezin numbers of some operators, including truncated Toeplitz operators. We also prove an operator analog of some Young inequality and use it in proving of some inequalities for Berezin number of operators including the inequality ber (AB) ≤ ber (A) ber (B), for some operators A and B on 𝓗 (Ω). Moreover, we give in terms of the Berezin number a necessary condition for hyponormality of some operators.

• Educational Technology International
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• 제6권1호
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• pp.65-79
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• 2005

In a widely distributed environment, many occasions arise when people need to filter informationwith email clients. The existing information agents such as Maxims and Message Assistant have capabilities of filtering email messages either by an autonomous agent or by user-defined rules. FlexMA, a variation of FAMES (Flexible Asynchronous Messaging System) is proposed as an information filtering agent. Agents in our system can be scaled up to adapt user's various demands by controlling messages delivered among heterogeneous email clients. Several functionalities are split into each agent in terms of component configuration with the addition of multiple agents'cooperation and negotiation. User-defined rules are collected and executed by these agents in a semi-autonomous manner. This paper demonstrates how this design is feasible in a flexible message system.

• 한국환경교육학회지:환경교육
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• 제10권2호
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• pp.101-120
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• 1997

The objective of this research is to understand the current field and composition of environment related terminology used in middle and high school textbooks, to find out uniformity and relationship between them, and development for the future establishement and replacement in the environmental education, simultaneously. The results of this study are as follows: 1. The terms used in middle school textbooks were found out to be 334, while those used in high school were 717. Total terms used were 870(759 kinds) and those recorded in the environmental terminology dictionary were 362 including synonyms. 2. Of those 870, 211 terms (24.25%) which were the same words have been used in interlinked connection with the Middle and High schools. While 136 terms(15.63%) have been used in the only middle, and 524 terms(60.23%) have been used in the only high schools. In middle and high school environmental text books 211 (24.25%) terms were the same interlinked terms. Of those extracted terms, 136(15.63%) were used in the middle school 'environmental' textbooks and in high school, 524(60.23%) were used in 'environmental science' book. These results shows that there is big gap between middle and high school contents and we will need more consideration in selecting the terms and better substance. 3. The same terminologies used in both middle and high schools were total number of 676. In those terms 257 kinds(76.26%) were used in middle school 'environmental' text books, and 563 kinds(78.52%) in high school 'environmental science' text books. Here are some details : 1) Terms used as same meaning but different in expression in middle school: 83 kinds, 192 terms (11.99%). 2) Differently expressed in the same text book : in middle school - 20 kinds(2.64%) in high school - 61 kinds(8.04%) 3) Differently expressed terms between middle and high school: 51 kinds(6.72%) 4) Same meaning in 3 expressions or more : 19 kinds 4. Of the examined terms 362(including 43 synonyms) were defined in environmental dictionary which is 41.8% of the total words. In the future specialization in utmost fields will be needed 5. When dividing those examined terms according to the middle and high school curriculum, the most terms were used in nature and pollution fields following environmental preserving, artificial environment, and environmenatal counterplan. In middle schools the most used terms were in the field of environment pollution, preservation, counterplan, and sanitation. These results reflects the education goals and objectives of middle schools. But for the middle school 'environment' curriculum moret uniform distribution are needed and for the high schools' 'environmental science' program, the fields in artificial environment, industrization, urbanization, and sanitation should be intensified.

• 한국환경교육학회지:환경교육
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• 제10권2호
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• pp.121-132
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• 1997

The objective of this research is to understand the current field and composition of environment related terminology used in middle and high school textbooks, to find out uniformity and relationship between them, and development for the future establishement and replacement in the environmental education, simultaneously. The results of this study are as follows: 1. The terms used in middle school textbooks were found out to be 334, while those used in high school were 717. Total terms used were 870(759 kinds) and those recorded in the environmental terminology dictionary were 362 including synonyms. 2. Of those 870, 211 terms(24.25%) which were the same words have been used in interlinked connection with the Middle and High schools. While 136 terms(15.63%) have been used in the only middle, and 524 terms(60.23%) have been used in the only high schools. In middle and high school environmental tort books 211 (24.25%) terms were the same interlinked terms. Of those extracted terms, 136(15.63%) were used in the middle school 'environmental' textbooks and in high school, 524(60.23%) were used in 'environmental science' book. These results shows that there is big gap between middle and high school contents and we will need mere consideration in selecting the terms and better substance. 3. The same terminologies used in both middle and high schools were total number of 676. In those terms 257 kinds(76.26%) were used in middle school 'environmental' text books, and 563 kinds(78.52%) in high school 'environmental science' text books. Here are some details : 1) Terms used as same meaning but different in expression in middle school : 83 kinds, 192 terms(11.99%). 2) Differently expressed in the same tort book in kiddie school - 20 kinds(2.64%) in high school - 61 kinds(8.04%) 3) Differently expressed terms between middle and high school : 51 kinds(6.72%) 4) Same meaning in 3 expressions or more : 19 kinds 4. Of the examined terms 362(including 43 synonyms) were defined in environmental dictionary which is 41.8% of the total words. In the future specialization in utmost fields will be needed 5. When dividing those examined terms according to the middle and high school curriculum, the most terms were used in nature and pollution fields following environmental preserving, artificial environment and environmenatal counterplan. In middle schools the most used terms were in the field of environment pollution, preservation, counterplan, and santiation. There results reflects the education goals and objectives of middle schools. But for the middle school 'environment' curriculum moret uniform distribution are needed and for the high schools' 'enironmental science' program, the fields in artificial environment, industrization, urbanization, and sanitation should be intensified.