• Communications of the Korean Mathematical Society
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• v.35 no.1
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• pp.1-12
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• 2020

A pathos block line cut-vertex graph of a tree T, written P BL_c(T), is a graph whose vertices are the blocks, cut-vertices, and paths of a pathos of T, with two vertices of P BL_c(T) adjacent whenever the corresponding blocks of T have a vertex in common or the edge lies on the corresponding path of the pathos or one corresponds to a block B_i of T and the other corresponds to a cut-vertex c_j of T such that c_j is in B_i; two distinct pathos vertices P_m and P_n of P BL_c(T) are adjacent whenever the corresponding paths of the pathos P_m(v_i, v_j) and P_n(v_k, v_l) have a common vertex. We study the properties of P BL_c(T) and present the characterization of graphs whose P BL_c(T) are planar; outerplanar; maximal outerplanar; minimally nonouterplanar; eulerian; and hamiltonian. We further show that for any tree T, the crossing number of P BL_c(T) can never be one.

• Wind and Structures
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• v.11 no.4
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• pp.303-321
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• 2008

When first commissioned, the 1.6 km span 275kV Severn Crossing Conductor experienced large amplitude vibrations in certain wind conditions, but without ice or rain, leading to flashover between the conductor phases. Wind tunnel tests undertaken at the time identified a major factor was the lift generated in the critical Reynolds number range in skew winds. Despite this insight, and although a practical solution was found by wrapping the cable to change the aerodynamic profile, there remained some uncertainty as to the detailed excitation mechanism. Recent work to address the problem of dry inclined cable galloping on cable-stayed bridges has led to a generalised quasi-steady galloping formulation, including effects of the 3D geometry and changes in the static force coefficients in the critical Reynolds number range. This generalised formulation has been applied to the case of the Severn Crossing Conductor, using data of the static drag and lift coefficients on a section of the stranded cable, from the original wind tunnel tests. Time history analysis has then been used to calculate the amplitudes of steady state vibrations for comparison with the full scale observations. Good agreement has been obtained between the analysis and the site observations, giving increased confidence in the applicability of the generalised galloping formulation and providing insight into the mechanism of galloping of yawed and stranded cables. Application to other cable geometries is also discussed.

• Journal of Communications and Networks
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• v.5 no.2
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• pp.104-115
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• 2003

It is well known that Multiple Input Multiple Output (MIMO) systems offer the promise of achieving very high spectrum efficiencies (many tens of bit/s/Hz) in a mobile environment. The gains in MIMO capacity are sensitive to the presence of spatial and temporal correlation introduced by the radio environment. In this paper, we examine how MIMO capacity is influenced by a number of factors e.g., a) temporal correlation b) various combinations of low/high spatial correlations at either end, c) combined spatial and temporal correlations. In all cases, we compare the channel capacity that would be achievable under independent fading. We investigate the behaviour of "capacity fades," examine how often the capacity experiences the fades, develop a method to determine level crossing rates and average fade durations and relate these to antenna numbers. We also evaluate the influence of channel correlation on the capacity autocorrelation and assess the fit of a Gaussian random process to the temporal capacity sequence. Finally we note that the particular spatial correlation structure of the MIMO channel is influenced by a large number of factors. For simplicity, it is desirable to use a single overall correlation measure which parameterizes the effect of correlation on capacity. We verify this single parameter concept by simulating a large number of different spatially correlated channels.

• PNF and Movement
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• v.13 no.2
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• pp.111-118
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• 2015

Purpose: The purpose of this study was to describe the effects of proprioceptive neuromuscular facilitation (PNF) on episodes of foot drop and the ability to cross obstacles in stoke patients. Methods: The patient was a 57-year-old man with left hemiplegia. This patient displayed episodes of foot drop while walking and issues with crossing obstacles. The patient underwent therapeutic exercises and occupational therapy twice daily at a hospital five times a week. The patient was treated with PNF outside of these therapeutic sessions. Each session, which was 60 minutes in length, was conducted 3 times a week over 8 weeks. Over the course of treatment, a pre-test and post-test were completed. The patient walked for a test time of 6M. During the testing process, the patient crossed obstacles. In addition, the number of foot drop episodes was recorded. Each test was measured three times to determine the mean value. Results: After the PNF treatments, the number of foot drop episodes decreased from five to one. The 6M walking test time during which the patient crossed obstacles also decreased from 18 seconds to 10 seconds. Conclusion: The use of PNF treatments is beneficial to reduce the number of foot drop episodes while walking and to improve the ability to cross obstacles in stroke patients.

• Journal of Korea Water Resources Association
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• v.49 no.10
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• pp.809-821
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• 2016

The study area is local river of 671 (total length 3,741 km) in Gyeongnam prefecture, the results are as follows. Total number of river-crossing structures was investigated as 7,730, and it was found that structures were installed in 2.1 sites per 1 km (river length) on average. Diversion weirs for agriculture were 4006 (51.82%) and drop structures for channel bed maintenance were 3670 (47.48%), but the rest (riverbed road etc.) were 54 (0.70%). The number of high structures (height > 1.0 m) that affect many impact in upstream and downstream was investigated as 3,897 (51%), and the number of low structures (height < 0.5 m) that affect negligibly was 1109 (14%). Fish ladders have been installed on 640 (8%) structures in 153 (23%) rivers. In flood control and environment conservation, river-crossing structures brought about various impact that flood water level is raises and the eco-corridor is intercept. In order to improve these problems, we proposed a few engineering measures that can be realize with respect to river-crossing structures.

• FLOWER RESEARCH JOURNAL
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• v.17 no.4
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• pp.291-296
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• 2009

This experiment was conducted to investigate the propagation system by seed to check growth, flowering, and making seed of four-year-old seedling cactus of potted Astrophytum asterias 'Nudum', A. asterias 'Super Kabuto', and A. myriostigma 'Nudum'. Plant height and width of Astrophytum asterias 'Nudum' and A. asterias 'Super Kabuto' was 5.3 to 5.5 cm, and 2.5 cm. However, plant height and width of A. myriostigma 'Nudum' was 7.6 cm and 5.6 cm as divided into 8 sections of body. In A. asterias 'Nudum', the mean seeded pod from April to September was 37.0% and the number of seeds in a pod was 43.0. In A. asterias 'Super Kabuto', the mean seeded pod from April to September was 22.5% and the number of seeds in a pod was 26.2. However, the mean seeded pod of A. myriostigma 'Nudum' from April to September was 32.3% and the number of seeds in a pod was 57.4. Especially, the seeded pod and the number of seeds in a pod of A. asterias 'Nudum' in July was the highest, 72.0% and 66.0. The sib crossing obtained much more seeded pods and the number of seeds per pod than that of selfing in the Astrophytum. The self crossing was formed from 9.0 to 20.0% of seeded pod, and 12.0 to 16.0 seeds in a pod. However, sib crossing was formed 60.0% seeded pod and 68.0 seeds in a pod on July of A. myriostigma 'Nudum'.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.17 no.11
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• pp.1175-1184
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• 1992

A new classification method and recognition algorithms for printed Korean and Chinese character is studied for Korean text which contains both Korean and Chinese characters. The proposed method utilizes structural features of the vertical and horizontal vowel in Korean character. Korean characters are classified into 6 groups. Vowel and consonant are separated by means of different vowel extraction methods applied to each group. Time consuming thinning process is excluded. A modified crossing distance feature is measured to recognize extracted consonant. For Chinese character, an average of stroke crossing number is calculated on every characters, which allows the characters to be classified into several groups. A recognition process is then followed in terms of the stroke crossing number and the black dot rate of character. Classification between Korean and Chinese character was at the rate of 90.5%, and classification rate of Ming-style 2512 Korean characters was 90.0%. The recognition algorithm was applied on 1278 characters. The recognition rate was 92.2%. The densest class after classification of 4585 Chinese characters was found to contain only 124 characters, only 1/40 of total numbers. The recognition rate was 89.2%.

• Kyungpook Mathematical Journal
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• v.48 no.2
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• pp.255-280
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• 2008

We derive a formula for the colored Jones polynomial of 2-bridge knots. For a twist knot, a more explicit formula is given and it leads to a relation between the degree of the colored Jones polynomial and the crossing number.

• Journal of the Chungcheong Mathematical Society
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• v.19 no.4
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• pp.349-356
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• 2006

The aim of this paper is to endow a monoid structure on the set S of all oriented knots(links) under the operation ${\biguplus}$, called addition of knots. Moreover, we prove that there exists a homomorphism of monoids between ($S_d,\;{\biguplus}$) to (N, +), where $S_d$ is a subset of S with an extra condition and N is the monoid of non negative integers under usual addition.

• Journal of the Korean Data and Information Science Society
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• v.20 no.1
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• pp.191-202
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• 2009

In this study, we drive the one dimensional marginal transform function, probability density function and probability distribution function for the random variables $T_{{\xi}N}$ (Time taken by the servers during the vacations), ${\xi}_N$(Number of vacations taken by the servers) and ${\eta}_N$(Number of customers or units arrive in the system) by controlling the variability of two random variables simultaneously.