• Bulletin of the Korean Mathematical Society
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• v.61 no.3
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• pp.585-595
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• 2024

We show that a pseudo-Anosov map constructed as a product of the large power of Dehn twists of two filling curves always has a geodesic axis on the curve graph of the surface. We also obtain estimates of the stable translation length of a pseudo-Anosov map, when two filling curves are replaced by multicurves. Three main applications of our theorem are the following: (a) determining which word realizes the minimal translation length on the curve graph within a specific class of words, (b) giving a new class of pseudo-Anosov maps optimizing the ratio of stable translation lengths on the curve graph to that on Teichmüller space, (c) giving a partial answer of how much power is needed for Dehn twists to generate right-angled Artin subgroup of the mapping class group.

• Journal of Elementary Mathematics Education in Korea
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• v.7 no.1
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• pp.65-86
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• 2003

Mathematics textbooks are substitutive showing real characters of didactic transposition in pseudo-contextualization and pseudo-personalization. This study analyzed statistical graphs in elementary school mathematics textbooks according to the first to the 7th curriculum in Korea. It focused on the didactic principles used in those methods through those view of Didactic Transposition Theory. The features of the elementary school mathematics textbooks in Korea are investigated and described ethnomethodologically according to each curriculum periods in dividing bar graph, line graph, pictograph, graph of ratio, histogram. The teaching sequences and methods of the statistical graphs, order and methods of sub-learning activities, teaming data, matter of the learning activity indicator were summarized. Usually, the teaching sequences, excepting the graphs of ratio, statistical graphs are introduced in the second semester of each grade. The graph of ratio is introduced in the first semester of 6th grade. As a result of analysing sub-Loaming activities, using them increased from the first to the 7th curriculum and its form was fixed constructive and stable at the 4th curriculum textbooks. As a result of analysing the teaming data, the data of the social aspects are used more frequently and the data of the individual preferences trended more gradually. As a result of analysing the matter of the teaming activity indicators, concept-explanation question style were used more frequently. Statement-practice style and consideration style trended gradually. Concluding remarks are: First, the didactic transposition of the elementary school mathematics textbooks developed systematically according to the first to the 7th curriculum; Second, mathematics textbooks gradually introduced the positive learning style of activity and the learners' spontaneousness; Third, more concrete practice activities and reflective activities were variously introduced considering the level and interest of each elementary student.

• Journal of the Korean Institute of Telematics and Electronics
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• v.6 no.3
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• pp.8-11
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• 1969

In the precision measurement of the voltage standing wave ratio (VSWR) or reflection coefficient by means of the slotted line technique, one of the important factors is the maximum error due to the discontinuities and multi-reflection in the slotted line. Particularly, this error becomes a critical factor when the VSWR or the reflection coefficient to be measured is very small. In this paper, the exact expression of this error is obtained by means of the Signal flow graph method.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38B no.4
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• pp.257-265
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• 2013

In this paper, we proposed a Dynamic Channel Assignment (DCA) scheme called Graph Coloring based DCA (GC-DCA) to improve system performance for downlink femtocell networks with high density femto Access Point (AP) deployments. The proposed scheme consists of two steps: one is a femto AP grouping step considering interference and the other is a DCA step considering Signal to Interference plus Noise Ratio (SINR) for femto User Equipments (UEs). Simulation results show that the proposed GC-DCA outperforms other schemes in terms of the mean femto UE capacity and probability of femto UEs which have capacities less than a given transmit rate.

• Journal of KIISE
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• v.44 no.7
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• pp.710-718
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• 2017

As graphs are becoming increasingly large, the costs for storing and managing data are increasing continuously. Shortest path discovery over a large graph requires long running time due to frequent disk I/Os and high complexity of the graph data. Recently, graph summarization techniques have been studied, which reduce the size of graph data and disk I/Os by representing highly dense subgraphs as a single super-node. Decompressing should be minimized for efficient shortest path discovery over the summarized graph. In this paper, we analyze the decompression performance of a summarized graph and propose an approximate technique that discovers the shortest path quickly with a minimum error ratio. We also propose an exact technique that efficiently discovered the shortest path by exploiting an index built on paths containing super-nodes. In our experiments, we showed that the proposed technique based on the summarized graph can reduce the running time by up to 70% compared with the existing techniques performed on the original graph.

• Proceedings of the IEEK Conference
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• 2000.09a
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• pp.671-674
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• 2000

In this paper, we present a robust global registration algorithm for multi-frame image mosaics. When we perform a pair-wise registration recovering a projective transformation between two consecutive frames, severe mis-registration among multiple frames, which are not consecutive, can be detected. It is because the concatenation of those pair-wise transformations leads to global alignment errors. To overcome those mis-registrations, we propose a new algorithm using multiple frames for constructing image mosaics. We use a graph to represent the temporal and spatial connectivity and show that global registration can be obtained through the search for an optimal path in the constructed graph. The definition of an adequate objective function characterizing the global registration provides a direct manipulation of the graph. In the presence of moving objects, especially large ones compared with low texture backgrounds, by using the likelihood ratio as the objective function, we can deal with some of the most challenging videos like basketball or soccer Moreover, the algorithm can be parallelized so it can be more efficiently implemented. Finally, we give some experimental results from real videos.

• Journal of Oriental Neuropsychiatry
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• v.13 no.2
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• pp.41-56
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• 2002

The Analysis of MMPI and Clinical Study was carried out the 28 patients with somatoform disorder and depressive disorder who were treated in Daejeon University Oriental Hospital from 19 June 2001 to 17 April 2002. The results were summarized as follows. 1. The ratio of female was higher, especially in the depressive disorder, the ratio of female was higher and in the age distribution, the 40 aged were higher frequence. 2. In the somatoform disorder, symptoms appeared to be busy in physical symptoms, and they were in descending order the digestive organs system, head and face portion and musculoskeletal system symptoms, in the depressive disorder, appeared to be busy in psychosomatic system symptoms and in the prescription drugs, soyosan(逍遙散), punsimkiyyin(分心氣飮) were used to be busy. 3. In the scales of L, F, K, somatoform disorder showed ${\wedge}$ typed graph, and depressive disorder showed ${\vee}$ typed graph. 4. In the somatoform disorder, scales of Hs, Hy, D, Pa were higher, and in the depressive disorder, scales of Hy, Hs, Pd, D were higher. 5. In the scales of Hs, D, Hy, somatoform disorder showed ${\vee}$ typed graph, and depressive disorder showed/typed graph. 6. the average of T-scores and the ratio over 65 score and 70 score showed common distribution.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.12
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• pp.2287-2297
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• 2007

The proposed ANIDS(Advanced Network Intrusion Detection System) which is network-based IDS using Association Rule Mining, collects the packets on the network, analyze the associations of the packets, generates the pattern graph by using the highly associated packets using Association Rule Mining, and detects the intrusion by using the generated pattern graph. ANIDS consists of PMM(Packet Management Module) collecting and managing packets, PGGM(Pattern Graph Generate Module) generating pattern graphs, and IDM(Intrusion Detection Module) detecting intrusions. Specially, PGGM finds the candidate packets of Association Rule large than $Sup_{min}$ using Apriori algorithm, measures the Confidence of Association Rule, and generates pattern graph of association rules large than $Conf_{min}$. ANIDS reduces the false positive by using pattern graph even before finalizing the new pattern graph, the pattern graph which is being generated is compared with the existing one stored in DB. If they are the same, we can estimate it is an intrusion. Therefore, this paper can reduce the speed of intrusion detection and the false positive and increase the detection ratio of intrusion.

• Journal of Korean Society for Quality Management
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• v.46 no.3
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• pp.651-658
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• 2018

Purpose: The algorithm described in Lim(1998) is available to determine the sample size directly given specified significance level, power and signal-to-noise ratio. We research on the efficient determination of the sample size by visual methods. Methods: We propose three graphs for investigating the mutual relationship between the sample size r, power $1-{\beta}$ and the detectable signal-to-noise ratio ${\Delta}$. First graph shows the relationship between ${\Delta}$ and $1-{\beta}$ for the given r and it can be checked whether the power is sufficient enough. Second graph shows the relationship between r and ${\Delta}$ for the given power $1-{\beta}$. Third graph shows the relationship between r and $1-{\beta}$ for the given ${\Delta}$. It can be checked that which effects are sensitive to the efficient sample size by investigating those graphs. Results: In factorial design, randomized block design and the split plot design how to determine the sample size directly given specified significance level, power and signal-to-noise ratio is programmed by using R. A experiment to study the split plot design in Hicks(1982) is used as an example. We compare the sample sizes calculated by randomized block design with those by split plot design. By using graphs, we can check the possibility of reducing the sample size efficiently. Conclusion: The proposed visual methods can help an engineer to make a proper plan to reduce the sample size.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.03a
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• pp.1490-1495
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• 2005

In this study, Model test of concrete frame structures with various shapes and locations are carried out by means of applying Peck's(1969) settlement method. The results of the model test indicated that important correlations existed between the behavior of frame structure and ground movement. Also, the damage level of frame structure closely influenced by the phase of excavation. Therefore, prediction of damage level at early phase of construction should be very precise. The damage level graph by Cording et al.(2001), the angular distortion provided gradually more serious damage to frame structures for the all cases. But the damage level graph by Burland(1997), was difficult to confirm because of very small amount of deflection ratio.