• East Asian mathematical journal
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• v.28 no.5
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• pp.579-585
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• 2012

Let D be a finite digraph with the vertex set V(D) and arc set A(D). A two-valued function $f:V(D){\rightarrow}\{-1,\;1\}$ defined on the vertices of a digraph D is called a signed 2-independence function if $f(N^-[v]){\leq}1$ for every $v$ in D. The weight of a signed 2-independence function is $f(V(D))=\sum\limits_{v{\in}V(D)}\;f(v)$. The maximum weight of a signed 2-independence function of D is the signed 2-independence number ${\alpha}_s{^2}(D)$ of D. Recently, Volkmann [3] began to investigate this parameter in digraphs and presented some upper bounds on ${\alpha}_{s}^{2}(D)$ for general digraph D. In this paper, we improve upper bounds on ${\alpha}_s{^2}(D)$ given by Volkmann [3].

• Kyungpook Mathematical Journal
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• v.56 no.4
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• pp.1103-1113
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• 2016

In this paper, we study a directed simple graph ${\Gamma}_S(N)$ for a near-ring N, where the set $V^*(N)$ of vertices is the set of all left N-subsets of N with nonzero left annihilators and for any two distinct vertices $I,J{\in}V^*(N)$, I is adjacent to J if and only if IJ = 0. Here, we deal with the diameter, girth and coloring of the graph ${\Gamma}_S(N)$. Moreover, we prove a sufficient condition for occurrence of a regular element of the near-ring N in the left annihilator of some vertex in the strong zero-divisor graph ${\Gamma}_S(N)$.

• Journal of the military operations research society of Korea
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• v.30 no.1
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• pp.30-47
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• 2004

This research considers a Network Diversion Problem (NDP) in the directed graph, which is to identify a minimum cost set of links to cut so that any communication paths from a designated source node to a destination node must include at least one link from a specified set of arcs which is called the diversion arcs. We identify a redundant constraint from an earlier formulation. The problem is known to be NP-hard, however a detailed proof has not been given. We provide the proof of the NP-hardness of this problem. We develop a tabu search algorithm that includes a preprocessing procedure with two steps for removing diversion arcs as well as reducing the problem size. Computational results of the algorithm on instances of general graphs and grid graphs are reported.

• Journal of the Korean Society of Safety
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• v.14 no.2
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• pp.140-147
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• 1999

Currently, the consumer pattern is directed to small quantity and high variety these days. World market is led by technological innovations and changes rapidly. To survive in this environment, the raising of small and medium enterprises is highly desirable. In the context of nationwide restructuring, competitive medium and small industries which are in good financial status should lead the nation's economy. But general ignorance of the safety issues could lead to a miss management of this industry in this field. In this study, actual condition and improvement of safety management are as follows; We have to 1) find out the factors which endangers this industry, and set a proper guideline for safety management. 2) encourage safety management of these industries by themselves, and advertise and provide technical support for using PC and internet. 3) set a higher standard of safety issue when accrediting a prospective medium and small industry, and have a firm control of this issue once accredited. 4) supply more governmental financial aids to terms of safety issues for medium and small industries.

• Cross-Cultural Studies
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• v.35
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• pp.237-268
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• 2014

Examining swear words found in Korean and English, we aim to answer the following two questions: (i) 'What words develop into swear words?' and (ii) 'Why they do?' The utility of a swear word is frequently recognized as intimidation directed towards an opponent, emotional catharsis, and solidarity building among in-group members (Jay 1992, 2000, Kim 1997). We seek to go beyond this simple enumeration of possible functions of swearing and suggest an underlying mechanism at work to explain how these functions are achieved and why only certain types of words are employed in this pursuit. A close examination reveals that a swear word must contain either taboo or sadism as an essential component. Sexual pleasure adds another dimension to the basic components. Thus, if an expression contains a subset of the component set {taboo, sadism, sex} in its semantics, it becomes available for swearing (one of the underlined components must be included in the set). For example, many religiously sacred expressions and words for excretion are common swear words as they violate social and religious taboo. On the other hand, words referring to social minorities are a convenient target for sadism. Furthermore, words describing sexual activity contain all three components, violating social taboo, evoking sadism, and giving the initiator guilty sexual pleasure. A combination of the components can produce an emotional effect called catharsis for the initiator. When directed towards others, these components, especially taboo and sadism, can be exploited as a verbal attack, an intimidation, preceding or replacing a physical attack. However, solidarity building is analyzed as a secondary function of swearing, achieved by sharing a sense of accomplice when in-group members behave badly together, such as violating social taboo and committing sadism.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.11 no.5
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• pp.159-171
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• 2011

This paper suggests an algorithm that obtains the Minimum Spanning Tree for directed graph (DMST). The existing Chu-Liu/Edmonds DMST algorithm has chances of the algorithm not being able to find DMST or of the sum of ST not being the least. The suggested algorithm is made in such a way that it always finds DMST, rectifying the disadvantage of Chu-Liu/Edmonds DMST algorithm. Firstly, it chooses the Minimum-Weight Arc (MWA) from all the nodes including a root node, and gets rid of the nodes in which cycle occurs after sorting them in an ascending order. In this process, Minimum Spanning Forest (MST) is obtained. If there is only one MSF, DMST is obtained. And if there are more than 2 MSFs, to determine MWA among all MST nodes, it chooses a method of directly calculating the sum of all the weights, and hence simplifies the emendation process for solving a cycle problem of Chu-Liu/Edmonds DMST algorithm. The suggested Sulee DMST algorithm can always obtain DMST that minimizes the weight of the arcs no matter if the root node is set or not, and it is also capable to find the root node of a graph with minimized weight.

• Journal of the Korean Society of Earth Science Education
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• v.11 no.3
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• pp.172-181
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• 2018

The purpose of this study is to investigate the impact on self-directed learning ability and science process skills by utilizing 'Thinking Maps' in a science class. This particular study was proceeded to 5th grader at B elementary school, there was a mutual agreement with a teacher about assigning a research group and a comparison group and it was agreed by students and explaining the reason and purpose of the study. The researchers visited the school and selected 24 students in the research class and 24 students in the comparative class. For a research group, an experimental group, homeroom teacher, proceeded a science class with the application of 'Thinking Maps'. The experimental period was set up as a 40 minutes class unit for 12 weeks. After an experimental group, self-directed learning ability and science process skills were examined, data collection and data analysis were proceeded by order. The following experimental results are as below. First, the application of 'Thinking Maps' method in the class was effective in self-directed learning ability. Second, the application of 'Thinking Maps' method in the class was effective in scientific process skills. Third, the application of 'Thinking Maps' method in the class had a positive cognition from the learners in the experimental group. Based on the discussions and implications of the results of this study, some suggestions in the follow - up study are as follows. First, applying Thinking Maps technique to various science classes to see the effects can also be suggested as one of the new teaching methods. Second, testing the effects of applying different grades of elementary school students using the Thinking Maps technique could also be highlighted as another way of teaching science classes.

• The Journal of Korean Association of Computer Education
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• v.19 no.3
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• pp.21-34
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• 2016

This study aims to develop user experience based mathematical program for self-directed learning. To meet its aim this program is designed and developed according to the process and method of 'ADDIE', general design model of education program. The features of this program are as follows. First, teacher can set questions conveniently through intuitive system of web and learner can solve questions at anytime and anywhere through instant access to application. Second, learner can solve different types of questions based on powerful question database and teacher can provide instantaneous feedback on them. Third, learner's circulation learning can be possible by utilizing paper-video explanation and wrong answer note and teacher supports learner's active learning management though group achievement management.

• Journal of Korea Multimedia Society
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• v.20 no.3
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• pp.533-542
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• 2017

Novels include various character names, depending on the genre and the spatio-temporal background of the novels and the nationality of characters. Besides, characters and their names in a novel are created by the author's pen and imagination. As a result, any proper noun dictionary cannot include all kinds of character names. In addition, the novels translated into Korean have character names consisting of two or more nouns (such as "Harry Potter"). In this paper, we propose a method to extract noun phrases for character names and to cluster the noun phrases into coreferents for the same character name. In the extraction of noun phrases, we utilize KKMA morpheme analyzer and CPFoAN character identification tool. In clustering the noun phrases into coreferents, we construct a directed graph with the character names extracted by CPFoAN and the extracted noun phrases, and then we create name sets for characters by traversing connected subgraphs in the directed graph. With four novels translated into Korean, we conduct a survey to evaluate the proposed method. The results show that the proposed method will be useful for speaker identification as well as for constructing the social network of characters.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.11
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• pp.2441-2446
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• 2009

Wireless Sensor Network collects a data from the specific area and the control is composed of small sensor nodes. Like this sensors to after that is established at the beginning are operated with the battery, the operational duration until several years must be continued from several months and will be able to apply the resources which is restricted in efficiently there must be. In this paper RHC (rounting history cache) applies in Directed Diffusion which apply a data central concept a reliability and an efficiency in data transfer course set. RHC algorithms which proposes each sensor node updated RHC of oneself with periodic and because storing the optimization course the course and, every event occurrence hour they reset the energy is wasted the fact that a reliability with minimization of duplication message improved.