• Title/Summary/Keyword: double difference

Search Result 1,099, Processing Time 0.022 seconds

The Comparison of Plantar Pressure on Double Limb Support and Single Limb Support according to Soft Surface (연성면에 따른 양발지지와 한발지지 시 족저압 비교)

  • Lee, Jeon-Hyeong;Chung, Hyeung-Jae;Kim, Shin-Gyun
    • PNF and Movement
    • /
    • v.11 no.2
    • /
    • pp.95-102
    • /
    • 2013
  • Purpose : The purpose of this study was to investigate a plantar pressure distribution and the trajectory of the center of pressure on double limb support and single limb support according to level surface, air cushion, and aero step. Methods : 21 healthy adults participated in this study. The plantar pressure were assessed at three different surface conditions(on the level surface, air cushion, and aero step) on double limb support and single limb support. Testing orders were selected randomly. Results : Plantar pressure distribution show a significant difference contact area 1 and contact area 3 on double limb support and single limb support. The trajectory of the center of pressure show an significant difference anteroposterior(AP), mediolateral(ML), and total displacement on double limb support and single limb support. Conclusion : Through the use of soft surface as air cushion and aero step will be using the ankle strategy. This will be to strengthen the muscles around the ankle. Consequently, should help to improve stability and coordination.

Friction Effects on the Performance of Double-Bumped Air Foil Bearings (이중범프포일 공기베어링의 성능에 미치는 마찰효과)

  • Kim, Young-Cheol;Lee, Dong-Hyun;Kim, Kyung-Woong
    • Tribology and Lubricants
    • /
    • v.23 no.4
    • /
    • pp.162-169
    • /
    • 2007
  • This paper deals with friction effects on the performance of double-bumped AFBs. The stiffness and damping coefficients of the double bump vary depending on the external load and its friction coefficient. The double bump can be either in the single or double active region depending on vertical deflection. The equivalent stiffness and damping coefficients of the bump system are derived from the vertical and horizontal deflection of the bump, including the friction effect. A static and dynamic performance analysis is carried out by using the finite difference method and the perturbation technique. The results of the performance analysis for a double-bumped AFB are compared with those obtained for a single-bumped AFB. This paper successfully proves that a double bumped AFB has higher load capacity, stiffness, and damping than a single-bumped AFB in a heavily loaded condition.

Performance Analysis of Double-Bumped Air Foil Bearings (이중범프포일 공기베어링의 성능해석)

  • Kim, Young-Cheol;Lee, Dong-Hyun;Kim, Kyung-Woong
    • Tribology and Lubricants
    • /
    • v.23 no.3
    • /
    • pp.123-129
    • /
    • 2007
  • This paper presents a theoretical model for the analysis of double-bumped AFBs. The stiffness and damping coefficients of the double bump vary depending on the external load and its friction coefficient. In the case of a lightly loaded condition where only the upper bump contributes to deformation, the double bump is in the single active region. In the case of a heavily loaded condition where both the upper and lower bumps contribute to deformation, the double bump is in the double active region. So the double bump can be either in the single or double active region depending on vertical deflection. The equivalent stiffness and damping coefficients of the bump system are derived from the vertical and horizontal deflection of the bump, including the friction effect. A static and dynamic performance analysis is carried out by using the finite difference method and the perturbation technique. The results of the performance analysis for a double-bumped AFB are compared with those obtained for a single-bumped AFB. This paper successfully proves that a double bumped AFB has higher load capacity, stiffness, and damping than a single-bumped AFB in a heavily loaded condition.

A Case Study on Field Construction of Cold Weather Mass Concreting Using Double Bubble Sheets and Hydration Heat Difference Method (이중 버블시트 및 수화발열량차 공법에 의한 한중매스콘크리트의 현장적용 연구)

  • Kim Jong;Yoon Jae-Ryung;Jeon Chung-Keun;Shin Dong-An;Oh Seon-Gyo;Han Cheon-Goo
    • Proceedings of the Korean Institute of Building Construction Conference
    • /
    • 2006.05a
    • /
    • pp.15-18
    • /
    • 2006
  • The test result of mat concrete applying both hydration heat difference and insulation curing method on new construction of Cheongju university educational building are summarized as following. Both fresh concrete and compressive strength properties were satisfied In aimed value. Setting time of concrete incorporating 15% of fly ash(FA) retarded 1.2 hour than control concrete. Temperature history of mali concrete indicated that the highest temperature of center was exhibited at $126^{\circ}C$ after 51 hours while the highest temperature of upper section was $10.6^{\circ}C$ after 46 hours. Temperature Difference between center and surface was managed at less than $6^{\circ}C$ during whole curing period. In addition the temperature of upper section secured more than $3.3^{\circ}C$ while the temperature of outside was indicated at less than $-10^{\circ}C$. Maturity by parts of construction secured more than $30^{\circ}C$ DD higher than outside at 3 days. The more number of times, applying insulation curing method by double bubble sheets, increased, the higher economic effect was secured. Overall it was clear that applying both double bubble sheets and hydration heat difference method on this new construction can resist hydration heat crack, early frost demage and strength decrease. It also significantly contributed quality improvement of cold weather concreting

  • PDF

A CLASS OF COMPLETELY MONOTONIC FUNCTIONS INVOLVING DIVIDED DIFFERENCES OF THE PSI AND TRI-GAMMA FUNCTIONS AND SOME APPLICATIONS

  • Guo, Bai-Ni;Qi, Feng
    • Journal of the Korean Mathematical Society
    • /
    • v.48 no.3
    • /
    • pp.655-667
    • /
    • 2011
  • A class of functions involving divided differences of the psi and tri-gamma functions and originating from Kershaw's double inequality are proved to be completely monotonic. As applications of these results, the monotonicity and convexity of a function involving the ratio of two gamma functions and originating from the establishment of the best upper and lower bounds in Kershaw's double inequality are derived, two sharp double inequalities involving ratios of double factorials are recovered, the probability integral or error function is estimated, a double inequality for ratio of the volumes of the unit balls in $\mathbb{R}^{n-1}$ and $\mathbb{R}^n$ respectively is deduced, and a symmetrical upper and lower bounds for the gamma function in terms of the psi function is generalized.

Effect of Ribcage Stabilization Using a Belt on EMG Activity of the Abdominal Muscles During Double Leg Lowering in the Supine Position (벨트를 이용한 가슴우리 고정이 누운자세에서 다리내리기 동안 복부 근육들의 근활성도에 미치는 영향)

  • Weon, Jonghyuck
    • Journal of The Korean Society of Integrative Medicine
    • /
    • v.5 no.2
    • /
    • pp.25-32
    • /
    • 2017
  • Purpose : The purpose of this study was to determine the effect of ribcage stabilization using a belt in the supine position during double leg lowering (DLL) by investigating the electromyographic (EMG) activities of the abdominal muscles. Methods : Twenty-two subjects with lumbar extension syndrome were recruited. EMG activity was recorded from rectus abdominalis (RA) and internal oblique abdominalis (IO), external oblique abdominalis (EO) muscles while subjects performed three double leg lowering exercises: double leg lowering (DLL), double leg lowering with abdominal draw-in maneuver (DLL-ADIM), and double leg lowering with ribcage stabilization using a belt (DLL-belt). RA, IO, and EO EMG activity were analyzed via one-way repeated-measures analysis of variance (ANOVA). Bonferroni correction was performed where significant differences were identified (p<.017, .05/3). Results : RA, IO, and EO EMG activity differed significantly among the three exercises (p<.05). The use of post hoc pair-wise comparison with Bonferroni correction showed that RA muscle activity significantly differed among the three exercises (p<.017), and IO muscle activity in the DLL exercise was significantly decreased compared to the DLL-ADIM and DLL-belt exercises (p<.017). There was no significant difference between IO muscle activity for DLL-ADIM and DLL-belt exercises (p>.017). EO muscle activity in the DLL-belt exercise was significantly increased compared to both DLL and DLL-ADIM exercises (p<.017), but there was no significant difference between EO muscle activity for DLL and DLL-ADIM exercises (p>.017). Conclusion : DLL-belt is a more effective exercise for activating the abdominal muscles than DLL-ADIM exercise. Therefore, we recommend DLL-belt exercises for strengthening the abdominal muscles.

STABILITY OF THE G-FUNCTIONAL EQUATION

  • Kim, Gwang-Hui
    • Journal of applied mathematics & informatics
    • /
    • v.9 no.2
    • /
    • pp.837-844
    • /
    • 2002
  • In this paper, we obtain the Hyers-Ulam Stability for the difference equations of the form f(x + 1) = $\Gamma$(x)f(x), which is the reciprocal functional equation of the double gamma function.

Valuation of American Option Prices Under the Double Exponential Jump Diffusion Model with a Markov Chain Approximation (이중 지수 점프확산 모형하에서의 마코브 체인을 이용한 아메리칸 옵션 가격 측정)

  • Han, Gyu-Sik
    • Journal of Korean Institute of Industrial Engineers
    • /
    • v.38 no.4
    • /
    • pp.249-253
    • /
    • 2012
  • This paper suggests a numerical method for valuation of American options under the Kou model (double exponential jump diffusion model). The method is based on approximation of underlying asset price using a finite-state, time-homogeneous Markov chain. We examine the effectiveness of the proposed method with simulation results, which are compared with those from the conventional numerical method, the finite difference method for PIDE (partial integro-differential equation).

A Moving Object Tracking System from a Moving Camera by Integration of Motion Estimation and Double Difference (BBME와 DD를 통합한 움직이는 카메라로부터의 이동물체 추적 시스템)

  • 설성욱;송진기;장지혜;이철헌;남기곤
    • Journal of KIISE:Software and Applications
    • /
    • v.31 no.2
    • /
    • pp.173-181
    • /
    • 2004
  • In this paper, we propose a system for automatic moving object detection and tracking in sequence images acquired from a moving camera. The proposed algorithm consists of moving object detection and its tracking. Moving object can be detected by integration of BBME and DD method We segment the detected object using histogram back projection, match it using histogram intersection, extract and track it using XY-projection. Computer simulation results have shown that the proposed algorithm is reliable and can successfully detect and track a moving object on image sequences obtained by a moving camera.