• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2000년도 하계학술대회 논문집 D
• /
• pp.2320-2322
• /
• 2000

In this paper, the problem of the stability analysis for linear neutral delay-differential systems with nonlinear perturbations is investigated. Using Lyapunov second method, a new delay-dependent sufficient condition for asymptotic stability of the systems in terms of linear matrix inequalities (LMIs), which can be easily solved by various convex optimization algorithms, is presented. A numerical example is given to illustrate the proposed method.

• Nonlinear Functional Analysis and Applications
• /
• 제28권2호
• /
• pp.365-382
• /
• 2023

In this paper we prove the existence and uniqueness of solution of stochastic fractional neutral differential equations with Gaussian noise or Lévy noise by using the Picard-Lindelöf successive approximation scheme. Further stability results of nonlinear stochastic fractional dynamical system with Gaussian and Lévy noises are established. Examples are provided to illustrate the theoretical results.

• Journal of Mechanical Science and Technology
• /
• 제14권3호
• /
• pp.358-368
• /
• 2000

The hydrodynamic stability of the Karman boundary-layer flow due to a rotating disk has been numerically investigated for moving disturbance waves. The disturbed flow over a rotating disk can lead to transition at much lower Re than that of the well-known Type I instability mode. This early transition is due to the excitation of the Type II instability mode of moving disturbances. Presented are the neutral stability results concerning the two instability modes by solving new linear stability equations reformulated not only by considering whole convective terms but by correcting some errors in the previous stability equations. The reformulated stability equations are slightly different with the previous ones. However, the present neutral stability results are considerably different with the previously known ones. It is found that the flow is always stable for a disturbance whose dimensionless wave number k is greater than 0.75.

• 전기학회논문지
• /
• 제60권2호
• /
• pp.376-382
• /
• 2011

This paper proposes delay-dependent stability conditions of the fuzzy Markovian jumping Hopfield neural networks of neutral type with time-varying delays. By constructing a suitable Lyapunov-Krasovskii's (L-K) functional and utilizing Finsler's lemma, new delay-dependent stability criteria for the systems are established in terms of linear matrix inequalities (LMIs) which can be easily solved by various effective optimization algorithms. A numerical example is given to illustrate the effectiveness of the proposed methods.

• BMB Reports
• /
• 제44권10호
• /
• pp.665-668
• /
• 2011

In order to clarify the impact of Ca-binding sites (Ca1 and 2) on the conformational stability of neutral proteases (NPs), we have analyzed the thermal, pH and organic solvent stability of a NP variant, V189P/A195E/G203D/A268E (Q-mutant), from Salinovibrio proteolyticus. This mutant has shown to bind calcium more tightly than the wild-type (WT) at Ca1 and to possess Ca2. Q-mutant was resisted against autolysis, thermoinactivation and pH denaturation in a Ca-dependent manner and exhibited better activity in organic solvents compared to the WT enzyme. These results imply that Ca1 and Ca2 are important for the conformational stability of NPs.

• PNF and Movement
• /
• 제15권3호
• /
• pp.311-316
• /
• 2017

Purpose: Flatfeet are one of the risk factors of foot dysfunction and postural imbalance. The purpose of this study was to compare the limitation of stability (LOS) for the center of gravity (COG) between flatfeet and neutral feet on stable and unstable support surfaces. Methods: The study included 26 healthy, adult male participants: 14 with normal feet and 12 with flatfeet. The subjects were asked to incline the trunk maximumly to the left, right, anterior, and posterior directions and were asked to keep their feet on the floor with the knee extension. The subjects had 30 seconds of rest time between the tasks. The LOS (anterior, posterior, left, right) of COG was measured by Balance Trainer (BT4, Hur-labs, Tampere, Finland). An independent t- test was used to compare the LOS of COG between flatfeet and normal feet on stable and unstable support surfaces, respectively. Results: The LOS of the flatfeet group was generally decreased on stable support surfaces as compared to that of neutral feet, but it was not significantly different (p>0.05), while the LOS of the flatfeet group was significantly decreased compared to that of neutral feet on unstable support surfaces (p<0.05). Conclusion: This study suggested that the LOS of individuals with flatfeet may be decreased on unstable support surfaces and the postural balance of the flatfeet group may easily be disturbed on an unstable support surface.

• 대한치과보철학회지
• /
• 제54권4호
• /
• pp.407-412
• /
• 2016

심하게 흡수된 치조제를 지닌 환자에게 적절한 의치를 제공하기 위한 한 가지 방법으로써 중립대 인상 기법을 이용한 의치의 제작을 고려해 볼 수 있다. 중립대 내에 인공 치아를 배열하는 것은 다음의 두 가지 목적을 이루고자 함이다. 첫째, 치아가 정상적인 근육의 기능을 방해하지 않도록 하기 위함이며, 둘째, 의치에 저항하여 가해지는 근육 조직의 힘이 안정과 유지에 더 유리하게 작용할 수 있도록 하기 위함이다. 본 증례의 환자는 심한 잔존 치조제의 흡수를 보이는 78세 여자 환자로 오랜 기간 불안정한 상 하악 총의치를 사용하고 있었다. 의치의 안정과 유지를 향상시키기 위하여 중립대 인상 기법을 통한 새로운 의치의 제작을 계획하였다. Modeling compound를 이용하여 중립대를 인기하였으며 치아 배열 후 external impression을 시행함으로써 정확한 연마면을 형성할 수 있었다. 완성된 상 하악 총의치는 보다 향상된 안정과 유지를 보였으며 환자 역시 새로 제작된 의치에 만족감을 보였기에 이를 보고하고자 한다.

• 한국지능시스템학회논문지
• /
• 제18권2호
• /
• pp.151-156
• /
• 2008

본 논문은 뉴트럴 타입 시간 지연을 가지는 네트워크 기반 시스템의 안정도 분석 및 샘플치 퍼지 제어기 설계 방법에 관하여 논의한다. 먼저 대상이 되는 비선형 네트워크 시스템을 T-S (Takagi-Sugeno) 퍼지 모델로 표현한다. 제안하는 샘플치 퍼지 제어기를 모델링하는 퍼지 규칙과 같은 멤버쉽 함수를 가지게 설계한다. Lyapunov-Krasovskii의 안정화 이론을 도입하여 이를 바탕으로 뉴트럴 형태의 시간 지연을 갖는 T-S 퍼지 시스템의 안정도를 판별한다. T-S 퍼지 시스템의 안정도 조건을 제시하고 선형 행렬 부등식의 형태로 표현한다. 제안된 선형 행렬 부등식의 해를 통하여 샘플치 퍼지 제어기의 이득 값을 설계한다. 마지막으로, 본 논문에서 제안한 방법의 적용 가능성과 일반성을 평가하기 위하여 수치적인 예를 적용한다.

• 구강회복응용과학지
• /
• 제17권2호
• /
• pp.113-123
• /
• 2001

The success of complete denture prosthesis is to satisfy three basic requirements for the edentulous patient : maximum comfort, efficiency, and esthetic appearance. This can be achieved only if the dentures are both stable and retentive. When the residual alveolar ridge has resorbed significantly, stability and retention are more dependent on the correct position of the teeth and external surfaces of the denture. The stability and retention of the denture can be improved by locating the denture in the neutral zone and reproducing exact mandibular border movement for balanced occlusion. The neutral zone philosophy is based upon the concept that there exists a specific area where the musculature function will not unseat the denture in the mouth. In here, forces generated by the tongue are neutralized by the forces generated by the lips and cheeks. One of the simplest methods for recording border movements in three dimensions is to make stereographic record of condylar movement. Stereographs are made in the mouth during mandibular movement with intraoral clutches and central bearing point, and used in dictating the condylar movement on the articulator later by generating the condylar paths in doughy acrylic resin. Its procedure is simpler and more convenient than that of Pantograph. In this clinical report, we introduce the concept of neutral zone and stereograph in complete denture fabrication.

• 대한심미치과학회지
• /
• 제32권1호
• /
• pp.8-15
• /
• 2023

심하게 위축된 하악 치조제의 경우, 총의치의 통상적인 기능인상 과정을 통해서는 의치의 적절한 유지력과 안정성을 얻기가 어려울 수 있습니다. 이러한 환자에서는 중립대 인상기법을 사용하는 방식이 효과적인 대안이 될 수 있습니다. 중립 영역은 근육 신경계의 정상적인 구강 기능 동안 입 바깥쪽으로 향하는 혀의 압력과 안쪽으로 향하는 뺨과 입술의 압력이 균형을 이루는 영역으로 정의됩니다. 중립 영역 인상을 통해 만들어진 총의치는 유지력과 안정성을 향상시킬 뿐만 아니라 구치 부위에 적절한 혀 공간을 제공합니다. 또한 인공치아 주변 부위의 음식물 찌꺼기가 줄어들고 적절한 안면 지지대를 통해 미관이 개선됩니다.