• Kyungpook Mathematical Journal
• /
• 제45권4호
• /
• pp.561-570
• /
• 2005

Weak Crossed Product Algebras correspond to certain graphs called lower subtractive graphs. The properties of such algebras can be obtained by studying this kind of graphs ([4], [5]). In [1], the author showed that a weak crossed product is Frobenius and its restricted subalgebra is symmetric if and only if its associated graph has a unique maximal vertex. A special construction of these graphs came naturally and was known as standard lower subtractive graph. It was a deep question that when such a special graph possesses unique maximal vertex? This work is to answer the question partially and to give a particular characterization for such graphs at which the corresponding algebras are isomorphic. A graph that follows the mentioned characterization is called flexible. Flexibility is to some extend a generalization of the so-called Coxeter groups and its weak Bruhat ordering.

• Journal of applied mathematics & informatics
• /
• 제35권1_2호
• /
• pp.95-111
• /
• 2017

Recently, interval-valued fuzzy graph is a growing research topic as it is the generalization of fuzzy graphs. The interval-valued fuzzy graphs are more flexible and compatible than fuzzy graphs due to the fact that they allowed the degree of membership of a vertex to an edge to be represented by interval values in [0.1] rather than the crisp values between 0 and 1. In this paper, we introduce the concepts of regular and totally regular interval-valued fuzzy graphs and discusses some properties of the ${\mu}$-complement of interval-valued fuzzy graph. Self ${\mu}$-complementary interval-valued fuzzy graphs and self-weak ${\mu}$-complementary interval-valued fuzzy graphs are defined and a necessary condition for an interval valued fuzzy graph to be self ${\mu}$-complementary is discussed. We define busy vertices and free vertices in interval valued fuzzy graph and study their image under an isomorphism.

• 한국수학교육학회지시리즈E:수학교육논문집
• /
• 제26권2호
• /
• pp.177-203
• /
• 2012

중등교육과정에서 수학적 내용사이의 연결과 수학과 다른 학문 사이의 연결의 중요성이 강조되고 있다. 이에 본 연구에서는 미술과 수학이 모두 시 공간적 능력의 활용을 포함하는 학문이라는데 주목하여 그래프와 부품식 영역의 지도에서 활용 가능한 소집단 그림그리기 활동을 실시하였다. 일반계 고등학교 1학년 학생을 대상으로 실시한 소집단 그림그리기 활동과정에서 나타나는 학생들의 수학에 대한 흥미변화를 살펴보고자 하였으며, 학생의 전략적 사고의 촉진가능성을 살펴보고 그 구체적인 특정을 분석하는데 목적을 두었다. 연구 결과, 그래프를 활용한 소집단 그림그리기 활동은 학생들의 수학에 대한 흥미변화에 긍정적인 영향을 미쳤을 뿐만 아니라 활동과정에서 다양한 전략적 사고가 나타남으로써 이러한 활동이 고등사고활동인 전략적 사고를 촉진시키는데 효과적임을 알 수 있었다.

• 인터넷정보학회논문지
• /
• 제18권4호
• /
• pp.79-87
• /
• 2017

Company A, an embedded system manufacturer, provides its products to Company P which is the parent company of Company A. Both companies learned that they needed to find over 4,000 bugs before market release in order to meet the acceptable quality level. Traditionally, they had utilized time-series line graphs as their common performance measurement tool. These graphs compared accumulated numbers of bugs fixed with accumulated numbers of bugs found. Engineers in Company A had been under pressure to improve the process capacity because the line for bugs fixed was always below than the line for bugs found. By using a newly designed Bipolar diagram, engineers in Company A analyzed the process performance. And they were in a position to be more flexible for internal or inter-companies meeting. Authors explain an empirical study of a graphical and practical performance measurement tools relating to mainly the Bipolar diagram. As a result, the Bipolar diagram provides workload monitoring and performance measurement functions in a given timeframe by using the concepts of Optimum Process Line (or band) and Fair Process Capacity Zone.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 1993년도 한국자동제어학술회의논문집(국내학술편); Seoul National University, Seoul; 20-22 Oct. 1993
• /
• pp.330-335
• /
• 1993

This paper presents an efficient solution for a class of forbidden state problems by introducing a cyclic timed controlled marked graphs (TCMG's), a special class of timed controlled Petri nets (TCPN's) as a model of a class of discrete event systems (DES's). The state feedback control is synthesized, which is maximally permissive while guaranteeing the forbidden states will be avoided. The practical applications or tire theoretical results for an automated guided vehicle (ACV) coordination problem in a flexible manufacturing facility is illustrated.

• 대한전자공학회:학술대회논문집
• /
• 대한전자공학회 2002년도 ITC-CSCC -3
• /
• pp.1724-1727
• /
• 2002

Asynchronous circuits have the potential to solve the problems related to parameter variations such as gate delays in deep sub-micron technologies. However, current CAD tools for large-scale asyn-chronous circuits partition specification irrelevantly, because these tools cannot control the granularity of circuit decomposition. In this paper we propose a hierarchical Control/Data Flow Graph (CDFG) containing nodes that are flexibly partitioned or merged into other nodes. We show a partitioning algorithm for such CDFGs to generate handleable Signal Transition Graphs (STGs) for asynchronous synthesis tools. The algorithm a1lows designers to assign the maximum number of signals of partitioned nodes considering of timality. From an experiment, this algorithm can flexibly partition and result in more compact asynchronous controllers.

• 대한수학교육학회지:수학교육학연구
• /
• 제22권2호
• /
• pp.137-162
• /
• 2012

자료를 표현하기 위해 선택되는 그래프와 그의 특징은 자료 수집의 목적 및 맥락, 그리고 수집된 자료의 유형에 의해 결정되기 때문에 통계적 자료를 표현하는 그래프에 대한 학습을 위해 학생들은 측정과 관련된 맥락에 대한 이해를 필요로 한다. 본 연구에서는 중학교 학생들이 자료와 그래프를 선택하고 해석할 때, 측정과 척도에 근거한 비판적 사고를 통해 맥락적 영역과 통계적 영역 사이의 상호적 전환을 보이고 있는지 살펴보았다. 조사결과, 학생들은 맥락적 영역과 통계적 영역 사이의 상호 전환을 필요로 하는 자료의 측정과 자료를 표현하는 척도와 관련한 비판적 사고가 부족함을 확인하였다. 특히 학생들은 제시된 자료나 그래프의 정보에 대해 의심을 거의 품지 않는 경향을 보였으며, 또한 문항에서 제시한 통계적 조사의 목적과 같은 맥락에 비추어 문제점을 찾아내거나 유연성을 발휘하여 판단하는 능력이 부족하였다.

• Earthquakes and Structures
• /
• 제13권2호
• /
• pp.103-118
• /
• 2017

In vertical seismic isolation (VSI), a building is partitioned intentionally by vertical layers into two dynamically different substructures for seismic response reduction. Initially, a 1-story frame was partitioned into two substructures, interconnected by viscous and visco-elastic links, and seismic responses of the original and the vertically isolated structures (VIS) were obtained, considering a large number of stiffness and mass ratios of substructures with respect to the original structure. Color contour graphs were defined for presentation and investigation of large amounts of output results. Dynamic characteristics of the isolated structures were studied by considering the non-classical damping of the system, and then the effects of viscous and visco-elastic link parameters on the modal damping ratios were discussed. On this basis, three states of mass isolation, interactional state, and control mass were differentiated. Response history analyses were performed by Runge-Kutta numerical method. In these analyses, interaction of isolation ratios and link parameters, on response control of VIS was studied and the appropriate ranges for link parameters as well as the optimal ranges for isolation ratios were suggested. Results show that by using the VSI technique, seismic response reduction up to 50% in flexible substructure and even more in stiff substructure is achievable.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제3권1호
• /
• pp.5-25
• /
• 2009

In recent years the popularity of multi-hop wireless networks has been growing. Its flexible topology and abundant routing path enables many types of applications. However, the lack of a centralized controller often makes it difficult to design a reliable service in multi-hop wireless networks. While packet routing has been the center of attention for decades, recent research focuses on data discovery such as file sharing in multi-hop wireless networks. Although there are many peer-to-peer lookup (P2P-lookup) schemes for wired networks, they have inherent limitations for multi-hop wireless networks. First, a wired P2P-lookup builds a search structure on the overlay network and disregards the underlying topology. Second, the performance guarantee often relies on specific topology models such as random graphs, which do not apply to multi-hop wireless networks. Past studies on wireless P2P-lookup either combined existing solutions with known routing algorithms or proposed tree-based routing, which is prone to traffic congestion. In this paper, we present two wireless P2P-lookup schemes that strictly build a topology-dependent structure. We first propose the Ring Interval Graph Search (RIGS) that constructs a DHT only through direct connections between the nodes. We then propose the ValleyWalk, a loosely-structured scheme that requires simple local hints for query routing. Packet-level simulations showed that RIGS can find the target with near-shortest search length and ValleyWalk can find the target with near-shortest search length when there is at least 5% object replication. We also provide an analytic bound on the search length of ValleyWalk.

• 한국학교수학회논문집
• /
• 제16권3호
• /
• pp.539-560
• /
• 2013

본 연구의 목적은 고등학교 수학영재 학생들이 GrafEq를 활용한 디자인 활동을 하는 과정에서 나타나는 사고의 특성 알아보고자 함이다. 사전조사를 통해 GrafEq를 사용해 본 경험이 없고, 디자인 활동에 필요한 부등식의 영역을 학습한 과학 고등학교 학생 8명을 선발하여, 2인 1조로 4개의 팀으로 나누어 각각 6차시에 걸쳐 실험을 실시하였다. 연구 결과, 논리적 사고 및 수학적 추상화, 직관적 구조적 통찰, 유연한 사고, 발산적 사고 및 독창성, 패턴의 일반화 및 귀납적 추론과 같은 특성들이 나타났으며, 이를 통해 GrafEq에서의 디자인 활동은 학생들에게 다양한 사고를 자극함으로써 학생들의 인지적인 발달을 촉진시키는데 효과적임을 알 수 있었다.