• 제목/요약/키워드: maximal function

검색결과 415건 처리시간 0.022초

A BIO-ECONOMIC MODEL OF TWO-PREY ONE-PREDATOR SYSTEM

  • Kar, T.K.;Chattopadhyay, S.K.;Pati, Chandan Kr.
    • Journal of applied mathematics & informatics
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    • 제27권5_6호
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    • pp.1411-1427
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    • 2009
  • We propose a model based on Lotka-Volterra dynamics with two competing spices which are affected not only by harvesting but also by the presence of a predator, the third species. Hyperbolic and linear response functions are considered. We derive the conditions for global stability of the system using Lyapunov function. The optimal harvest policy is studied and the solution is derived in the interior equilibrium case using Pontryagin's maximal principle. Finally, some numerical examples are discussed. The nature of variations in the two prey species and one predator species is studied extensively through graphical illustrations.

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THE UNIFORM CLT FOR MARTINGALE DIFFERENCE ARRAYS UNDER THE UNIFORMLY INTEGRABLE ENTROPY

  • Bae, Jong-Sig;Jun, Doo-Bae;Levental, Shlomo
    • 대한수학회보
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    • 제47권1호
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    • pp.39-51
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    • 2010
  • In this paper we consider the uniform central limit theorem for a martingale-difference array of a function-indexed stochastic process under the uniformly integrable entropy condition. We prove a maximal inequality for martingale-difference arrays of process indexed by a class of measurable functions by a method as Ziegler [19] did for triangular arrays of row wise independent process. The main tools are the Freedman inequality for the martingale-difference and a sub-Gaussian inequality based on the restricted chaining. The results of present paper generalizes those of Ziegler [19] and other results of independent problems. The results also generalizes those of Bae and Choi [3] to martingale-difference array of a function-indexed stochastic process. Finally, an application to classes of functions changing with n is given.

CHAOTIC THRESHOLD ANALYSIS OF NONLINEAR VEHICLE SUSPENSION BY USING A NUMERICAL INTEGRAL METHOD

  • Zhuang, D.;Yu, F.;Lin, Y.
    • International Journal of Automotive Technology
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    • 제8권1호
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    • pp.33-38
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    • 2007
  • Since it is difficult to analytically express the Melnikov function when a dynamic system possesses multiple saddle fixed points with homoclinic and/or heteroclinic orbits, this paper investigates a vehicle model with nonlinear suspension spring and hysteretic damping element, which exhibits multiple heteroclinic orbits in the unperturbed system. First, an algorithm for Melnikov integrals is developed based on the Melnikov method. And then the amplitude threshold of road excitation at the onset of chaos is determined. By numerical simulation, the existence of chaos in the present system is verified via time history curves, phase portrait plots and $Poincar{\acute{e}}$ maps. Finally, in order to further identify the chaotic motion of the nonlinear system, the maximal Lyapunov exponent is also adopted. The results indicate that the numerical method of estimating chaotic threshold is an effective one to complicated vehicle systems.

NURBS Surface Global Interpolation에 대한 한 방법: II (A New Method of the Global Interpolation in NURBS Surface: II)

  • 정형배
    • 한국CDE학회논문집
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    • 제3권4호
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    • pp.243-250
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    • 1998
  • In parametric surface interpolation, the choice of the parameter values to the set of scattered points makes a great deal of difference in the resulting surface. A new method is developed and tested for the parametrization in NURBS surface global interpolation. This method uses the parameter value at the maximal value of relevant rational basis function, to assign the parameter values to the arbitrary set of design data. This method gives us several important advantages in geometric modeling, the freedom of the selection of knot values, the feasible transformation of the data set to the matrix, the possibility of affinite transformation between the design data and generated surface, etc.

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골격근 섬유의 수축성 특성의 다양성 (Diversity of contractile properties in skeletal muscle fibers)

  • 김식현
    • PNF and Movement
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    • 제2권1호
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    • pp.35-47
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    • 2004
  • Purpose : The purpose of this article was to review the literature on contractile properties of skeletal muscle with reference to its molecular and functional diversity. Method : This review outlines scientific findings regarding different contractile properties in skeletal muscle fibers, and discusses their involvement in functional diversity. Result & Conclusions: Muscle fibers possess distinct mechanical and energetic properties. Myosis, one of the primary contractile muscle proteins, displays structural, functional variability and plays the role of the molecular motor of muscle contraction. Muscle satellite cells are normally mitotically quiescent, but initiate proliferation and give rise to daughter myogenic precursor cells as required for the postnatal growth and regeneration of adult muscle. Passive extensibility is an important component of total muscle function because it allows for the maximal length of skeletal muscles. Proprioceptive neuromuscular facilitation(PNF) stretching can help to restore or improve flexibility and coordination, thereby improving overall muscle function.

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SOME APPLICATION OF THE UNION OF TWO 𝕜-CONFIGURATIONS IN ℙ2

  • Shin, Yong-Su
    • 충청수학회지
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    • 제27권3호
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    • pp.413-418
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    • 2014
  • It has been proved that the union of two linear star-configurations in $\mathbb{P}^2$ of type s and t for either $3{\leq}t{\leq}10$ or $\(\frac{t}{2}\)-1{\leq}s$ with $3{\leq}t$ has maximal Hilbert function. We extend the condition to $\[\frac{1}{2}\(\frac{t}{2}\)\]{\leq}s$, so that it is true for either $3{\leq}t{\leq}10$ or $\[\frac{1}{2}\(\frac{t}{2}\)\]{\leq}s$ with $3{\leq}t$, which extends the result of [6].

간격 차이(90° 굴곡 간격-신전 간격)와 슬관절 전 치환술 1년 후의 무릎 기능과의 관계 (Relationship between Knee Function at 1 Year Postoperation and Gap Difference (90° Flexion Gap-Extension Gap) in Total Knee Replacement)

  • 조명래;도정석;김경태;최원기
    • 대한정형외과학회지
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    • 제54권3호
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    • pp.254-260
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    • 2019
  • 목적: 슬관절 전 치환술 시, 90° 굴곡과 신전 시의 간격(gap) 차이와 술 후 1년째의 슬관절 기능과의 관계를 알아보고자 하였다. 대상 및 방법: 2017년 3월부터 6월까지 골관절염 환자를 대상으로 하여 시행된 내비게이션을 이용한 전치환술의 연속된 82예를 대상으로 시행된 전향적 연구이다. 간격 측정은 내비게이션을 이용하였으며, 슬개골을 towel clip을 이용하여 정복한 이후 간격을 측정하였다. 신전 시의 내측과 외측 간격의 평균과 90° 굴곡 시의 내측과 외측 간격의 평균값을 구한 이후 간격 차이(90° 굴곡 시의 간격-신전 간격)를 계산하였다. 간격 차이<0 mm, 0 mm≤간격 차이<2 mm, 2 mm≤간격 차이를 각각 1군, 2군, 3군으로 나누었다. 술 후 1년째, Knee Society score (KSS)와 함께 무릎의 최대 굴곡 각도를 측정한 이후, 각 군 간의 값을 비교하였다. 결과: 간격 차이의 값에 따라 나눈 군의 수는 1군이 37예, 2군이 29예, 3군이 16예였다. 술 후 1년째의 KSS knee는 평균 81.21±8.31, KSS function은 71.34±9.84, 그리고 무릎의 최대 굴곡 각도는 126.48°±7.28°였다. 간격 차이에 따른 1년 후의 KSS의 값은 통계적으로 유의한 차이가 없었다. Mann-Whitney test를 이용한 두 군 간의 비교에서 2 mm≤간격 차이를 보이는 3군이 1군과 2군에 비하여 통계적으로 유의하게 큰 최대 무릎 굴곡 각도를 보였다. 결론: 슬관절 전 치환술 시, 90° 굴곡 시의 간격이 신전 시의 간격보다 2 mm 이상 큰 경우에서 다른 군에 비하여 술 후 1년째의 최대 무릎 굴곡 각도가 통계적으로 유의하게 높았다.

엉덩허리근에 대한 수동 신장이 폐 기능에 미치는 영향 (The Effects of Passive Stretching of the Iliopsoas Muscles on Pulmonary Function)

  • 한동욱
    • 대한물리의학회지
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    • 제17권3호
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    • pp.79-86
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    • 2022
  • PURPOSE: By virtue of its location, the iliopsoas muscle has the potential to affect the function of the diaphragm. Therefore, the purpose of this study was to investigate the effects of passive stretching of the iliopsoas muscles on pulmonary function. METHODS: Twenty male university students participated in this study. Subjects with low back pain, negative results on the modified Thomas test, and chest breathing patterns not directly related to the function of the iliopsoas muscles were excluded from this study. A digital pulmonary function measuring device (Pony FX, COSMED Inc, Italy) was used to test pulmonary function. The test was performed three times: the first test before passive stretching, the second test 10 minutes after the first test, and the third after passive stretching. Passive stretching was performed 5 times for each of the left and right iliopsoas muscles. Passive stretching was carried out for 20 seconds followed by a 10-second break. The SPSSWIN (ver. 27.0) statistics program was used for data analysis, and the significance level was α =.05. RESULTS: Among slow vital capacity (SVC) parameters, tidal volume (VT), inspiratory reserve volume (IRV), inspiratory capacity (IC) and vital capacity (VC) improved significantly after passive stretching. Also, among the maximal effort vital capacity (MEVC) parameters, forced vital capacity(FVC) and forced expiratory volume in one second(FEV1) improved significantly after passive stretching. CONCLUSION: The results showed that among the various pulmonary function parameters measured, passive stretching of the iliopsoas muscles can improve the SVC and MEVC. Therefore, passive stretching of the iliopsoas muscles may be considered for use as a treatment method to improve pulmonary function.

호흡근 강화 훈련이 아급성 뇌졸중 환자의 폐기능과 보행 능력에 미치는 영향 (The Effects of Respiratory Muscle Strengthening Training on Pulmonary Function and Gait Ability in Subacute Stroke Patients)

  • 김진석;신원섭
    • 대한물리의학회지
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    • 제8권4호
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    • pp.489-496
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    • 2013
  • PURPOSE: The aim of this study was to investigate the effect of respiratory muscle strengthening training on pulmonary function and gait ability in patients with subacute stroke. METHODS: Eighteen inpatients with subacute stroke were recruited for this study. The subjects were randomized into two group. All study groups participated in a conventional stroke rehabilitation intervention 30minutes a day 5 times a week for 4 weeks. For subjects from the experimental group, respiratory muscle strengthening training was performed: 30minutes a day 3 times a week for 4 weeks. Outcomes such as the pulmonary function(Forced Vital Capacity, Forced Expiratory Volume in one second, Maximal Voluntary Ventilation) and gait ability(10m walk test, 6 minute walk test) were measured before and after training. RESULT: There were significant differences of pulmonary function(FVC, FEV1 and MVV) and gait ability(10m walk test, 6minute walk test) between pre and post in the experimental group. In comparison of two group, experimental group was significant different pulmonary function(FVC, FEV1, MVV) and gait ability(6minute walk test) than control group. but, There was no significant difference of the gait ability(10m walk test). CONCLUSION: This study showed experimental group can be used to improve pulmonary function and gait ability than control group. These findings suggest that the respiratory muscle strengthening training effect on pulmonary function and gait ability for rehabilitation in patients with subacute stroke.

융복합을 활용한 휠체어 트레드밀과 암에르고미터 점증부하운동검사 시 심폐기능, 운동자각도 및 젖산농도 비교 (A Comparison of Cardiopulmonary Function, RPE, and Blood Lactate following in Wheelchair Treadmill and Arm Ergometer GXT Test through Convergence)

  • 장홍영;김종혁
    • 디지털융복합연구
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    • 제14권9호
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    • pp.553-561
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    • 2016
  • 본 연구는 비장애인 휠체어 농구 선수 11명을 대상으로 휠체어트레드밀과 암 에르고미터의 점증부하운동검사 시 심폐기능, 운동자각도 및 젖산 농도를 비교하는데 목적이 있다. 연구방법으로는 휠체어트레드밀과 암 에르고미터의 점증부하운동검사 시 호흡가스분석기와 무선 심박수 측정기를 사용하여 심폐기능을 알아보았으며, 보그 스케일을 이용하여 운동자각도를 측정하였고, 젖산 분석기를 사용하여 안정 시, 운동직후, 회복기 2분, 4분, 6분, 10분의 혈중 젖산 농도를 측정하였다. 측정된 데이터는 SPSS 18.0 프로그램을 통하여 종속 t-검증(paired t-test)을 실시하여 분석하였고 통계적 유의수준은 .05로 설정하였다. 이 연구를 통하여 얻어진 결과는 다음과 같다. 첫째, 심폐기능 변인 중 최대산소섭취량은 암 에르고미터가 높게 나타났으며, 호흡교환율은 휠체어트레드밀이 높게 나타났으며, 최대 심박수는 휠체어트레드밀이 높게 나타났다. 둘째, 주관적 운동 강도에서는 종료 점에서 암 에르고미터에서 높게 나타났다. 셋째, 혈중 젖산 농도는 운동 직후 암 에르고미터에서 높게 나타났다.