• 대한수학회논문집
• /
• 제35권1호
• /
• pp.1-12
• /
• 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
• /
• 제11권4호
• /
• pp.303-321
• /
• 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
• /
• 제5권2호
• /
• pp.104-115
• /
• 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
• /
• 제13권2호
• /
• pp.111-118
• /
• 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.

• 한국수자원학회논문집
• /
• 제49권10호
• /
• pp.809-821
• /
• 2016

연구범위는 경남의 지방하천 671개소(총연장 3,741 km)이며, 연구내용을 간략히 요약하면 다음과 같다. 하천횡단구조물의 총수는 7,730개소로 조사되었으며, 하천연장 1 km 당 구조물이 평균 2.1개소씩 설치되어 있는 것으로 나타났다. 농업용수보가 4,006 (51.82%)개소였으며, 하상 유지시설(낙차공)은 3,670 (47.48%)개소였고 및 나머지(하상도로 등)는 54 (0.70%)개소로 조사되었다. 상하류에 큰 영향을 미치는 높이 1.0 m 이상은 3,897 (51%)개소, 영향이 비교적 미미한 높이 0.5 m 이하는 1,109 (14%)개소로 분석되었다. 어도는 153 (23%)개 하천에 640 (8%) 개소에 설치되어 있는 것으로 파악되었다. 하천횡단구조물이 치수적 측면에서 홍수시 수위상승을 초래하고 생태환경적 측면에서는 생태통로를 단절시키는 등 여러 문제점을 초래하고 있었다. 따라서, 도출된 문제점을 기초로 하천횡단구조물에 대한 공학적인 몇 가지 대책을 제시하였다.

• 화훼연구
• /
• 제17권4호
• /
• pp.291-296
• /
• 2009

분화용으로 가치가 있다고 판단되는 Astrophytum asterias 'Nudum', A. asterias 'Super Kabuto'와 A mynostlgma 'Nudum'의 실생 번식의 체계를 확립하기 위하여 3년생 실생을 온실에 입실한 후 11개월에 생육 및 개화조사를 하고 시기별 자가 수분 및 형매 수분에 따른 착과율 및 협당 종자수를 조사하였다. Astrophytwn asterias 'Nudum'과 A. asterias 'Super Kabuto'의 식물체 높이는 5.3~5.5 cm이고 식물체의 직경은 2.5cm이었으나, A. myriostigma 'Nudum'은 높이가 7.6 cm, 직경이 5.6 cm로 자랐다. A. asterias 식물체는 가시가 없고 8개의 결각으로 갈라졌으나 A. myriostigma는 4~5개로 갈라졌고 아주 작은 가시가 형성되었다. 평균 착과율과 꼬투리당 종자수는 A. asterias 'Nudum'은 37.0%, 43.0개이고, A. asterias 'Super Kabuto'는 22.5%, 26.2개이었으며, A. myriostigma는 32.3%, 57.4개 이였다. 시기별로 7월의 결실율 및 꼬투리당 종자수가 가장 많고 다음에는 6월과 8월로 나타났다. 특히 A. asterias 'Nudum'의 7월의 착과율은 72%로 가장 높았고 꼬투리당 종자수도 66개로 가장 많았다. A. asterias 'Nudum'의 자가 수정 착과율은 10%, 꼬투리당 종자수는 12개이고, 형매 교배 착과율은 72%, 꼬투리당 종자수는 66개이었다. A. myriostigma의 자가 수정 착과율은 20%, 꼬투리당 종자수는 16개이고, 형매 교배 착과율은 60%, 꼬투리당 종자수는 68개이었다. 이와 같이 Astrophytum 속 선인장을 7월에 형매교배를 한다면 결실율이 높고 많은 종자를 얻을 수 있다.

• 한국통신학회논문지
• /
• 제17권11호
• /
• pp.1175-1184
• /
• 1992

본 논문에서는 한자를 포함하는 한글 문서 인식을 위한 인쇄체 한글, 한자의 구분과 인식 방법에 대하여 연구하였다. 제안된 한글, 한자 구분 방법은 한글의 수직모음과 수평모음의 구조적 특징을 이용하였다. 한글은 6가지 형태로 분류하고 분류된 각 형태에 대하여 세선화 과정을 거치지 않고 모음 우선추출에 의한 자모분리를 행하고 분리된 자음에 대하여 변형된 교차거리 특징을 이용하여 인식하였다. 한자에 대해서는 획교차수의 평균치를 이용하여 전체 한자 대상문자에 대해 분류를 하였으며, 문자의 획교차수와 흑점비율 특징을 이용하여 인식하였다. 한글과 한자의 구분에서는 90.5%의 분류율을 얻었다. 한글인식에 있어서는 대상문자 명조체 2512자에 대하여 90.0%의 형태 분류율을 얻었다. 인식 결과 실험 데이타 1278자에 대하여 92.2%의 인식율을 얻었다. 한자인식에 있어서는 대상문자 4585자에 대하여 분류한 결과 최대밀집 구간은 124자로서 약 1/40 정도로 분류되었음을 알 수 있었고, 인식실험 결과 89.2%의 인식율을 얻었다.

• Kyungpook Mathematical Journal
• /
• 제48권2호
• /
• pp.255-280
• /
• 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.

• 충청수학회지
• /
• 제19권4호
• /
• pp.349-356
• /
• 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
• /
• 제20권1호
• /
• pp.191-202
• /
• 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.