• Journal of applied mathematics & informatics
• /
• v.29 no.1_2
• /
• pp.211-225
• /
• 2011

In this paper, a class of bi-directional associative memory (BAM) fuzzy cellular neural networks with distributed delays and impulses is formulated and investigated. By employing an integro-differential inequality with impulsive initial conditions and the topological degree theory, some sufficient conditions ensuring the existence and global exponential stability of equilibrium point for impulsive BAM fuzzy cellular neural networks with distributed delays are obtained. In particular, the estimate of the exponential convergence rate is also provided, which depends on the delay kernel functions and system parameters. It is believed that these results are significant and useful for the design and applications of BAM fuzzy cellular neural networks. An example is given to show the effectiveness of the results obtained here.

• The Pure and Applied Mathematics
• /
• v.26 no.3
• /
• pp.157-175
• /
• 2019

In this paper we define higher-order Stieltjes derivatives, and using Schaefer's fixed point theorem we investigate the existence of solutions for a class of differential equations involving second-order Stieltjes derivatives with two-point boundary conditions. The equations include ordinary and impulsive differential equations, and difference equations.

• Journal of the Institute of Electronics and Information Engineers
• /
• v.50 no.2
• /
• pp.3-10
• /
• 2013

Please In this paper, to cope with biased impulsive noise problems, a new information potential is proposed that can move the transmitted symbol points by modifying the information potential designed with Dirac-delta functions. Based on the proposed information potential a new blind algorithm is derived by employing an augmented filter structure. From the simulation results in the environment of biased impulsive noise, the conventional algorithms yield performance degradation by over 15 dB, but the proposed algorithm shows no performance degradation and holds the same steady state MSE of below -25 dB as after the initial convergence regardless of the channel conditions.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.15 no.3 s.96
• /
• pp.272-279
• /
• 2005

In this study the optimal isolation system for the prototype HIFD(high impulsive force device) is investigated. For this purpose, firstly, the dynamic behavior of a human body and a transmitted force under specific operation conditions are analyzed through a series of experimental works using the devised test setup. In order to design the optimal dynamic absorbing system, the parameter optimization process is performed using the simplified isolation system model based on the experimental results of linear impulse and transmitted force. Finally, under the parameters satisfying the constraints of the buffering displacement and the transmitted force, the performance of the designed isolation system for the prototype HIFD is evaluated by experiment.

• Journal of Astronomy and Space Sciences
• /
• v.15 no.1
• /
• pp.235-244
• /
• 1998

The solutions of orbital maneuver problem using the sliding mode control in the presence of the erath gravitational perturbations is obtained. Especially, the optimization of consuming fuel for maneuver is performed. The impulsive solution to Lambert's problem using the combined equation method to minimize total ${\Delta}V is used for the desired orbit and the maneuver times. Two-step sliding mode control method is introduced for satisfying the boundary conditions of finite-thrust rendezvous problem at the end of maneuver time. Using the new approach to the orbit maneuver problem, two-step sliding mode control, orbit maneuvers are processed. The solutions to a rendezvous using the optimal control are obtained, and they are compared to the results by two-step sliding control.According to the new approach for orbit maneuver, the thrust-coast-thrust type controller is obtained to make satellite to track desired Lambert's orbit, and the total ${\Delta}V$ required for maneuver is resonable in comparison with the impulsive solution to Lambert's problem. The final state variables, also are close to the boundary conditions at the end of maneuver times.

• Computational Structural Engineering
• /
• v.10 no.3
• /
• pp.167-174
• /
• 1997

Engineers must be aware of possible sources of chaotic behavior. They may render conventional design predictions untrustworthy and potentially unsafe because of the sensitivity to initial conditions. Dynamic responses of a spherical shell subjected to impulsive loading which act on the center are analyzed using the finite element method. The chaotic responses are identified by the standard methods, such as displacement-time histories, Poincare maps, and phase diagrams. The responses are chaotic, but, not so sensitive to the initial conditions, and the characteristics of responses are not changed with time, in contrast to the case of the responses of beam. The Poincare points scattered in the limited area represent that the responses are chaotic, but do not show the geometric structures. The snap-through phenomena of the shell to the side of the direction of the load or of the opposite direction, is analysed by using the energy diagram.

• Journal of the Korean Home Economics Association
• /
• v.45 no.8
• /
• pp.105-126
• /
• 2007

The aims of this study were to examine the actual conditions surrounding the purchasing of online game items and Internet cyberspace items by adolescents the propensity of adolescents to consume these items, to determine the difference in the propensity for high and low consumption of these items among adolescents, and to investigate the characteristics of the adolescents who show a high propensity for the consumption of Internet items. The data for this study were collected from 483 adolescent consumers who were middle school and high school students in the city of Bucheon in Gyeonggi Province. The statistical methods used for the data analysis included frequency, percentage, standard deviation, t-test, and one-way ANOVA. The results of the present study can be summarized as follows. The majority(79.5%) of the students surveyed had had the experience of purchasing items. Most students(67.5%) had a rare frequency of buying ($1{\sim}2$ times in a period of 6 months or less). Nearly half (47.9%) of the students spent less than 1000 won per month on the item(s) purchased. Most of the students purchased items with their parents' permission, but 26.6% of the students bought the items without their parents' permission. Most of the characteristics of the items purchased, such as the major item purchased, payment method, amount purchased per month, average amount spent per buying experience, and whether or not they had their parents' permission differed according to gender, grade level, record, and monthly allowance. The level of propensity to consume the items was not high. The propensity of imitation consumption (1.96) was lower than that of impulsive consumption (2.38) and conspicuous consumption (2.45). Most of the buying characteristics, including the major item purchased, payment method, amount purchased per month, average amount spent per buying experience, parents' permission, grade level, and monthly allowance were different between the high and low propensity for consumption groups.

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.35 no.2
• /
• pp.33-40
• /
• 2023

Wave overtopping rate is one of the most important design parameters for coastal structures. In this study, the physical model tests for measuring the wave overtopping have been conducted with the foreshore slope in front of the seawall. The bottom seabed for the coastal road area was fabricated at the wave flume for two areas in the East sea areas. The wave overtopping rate was measured for various water depths and wave conditions in each coastal area. In particular, the impulsive wave conditions were compared with the previous research and the similar trends of wave overtopping was observed. It could be known that the effect of foreshore slope was significant and should be concerned for applying theses formula like EurOtop.

• Journal of applied mathematics & informatics
• /
• v.12 no.1_2
• /
• pp.39-47
• /
• 2003

Sufficient conditions for asymptotic behavior of the solutions of nonlinear forced neutral delay differential equations with impulses are found. The results given in [2,4,6,7］are generalized and improved.

• Communications of the Korean Mathematical Society
• /
• v.35 no.4
• /
• pp.1329-1352
• /
• 2020

In this paper we consider a class of nonlinear evolution equations on infinite dimensional Banach spaces driven by vector measures. We prove existence and uniqueness of solutions and continuous dependence of solutions on the control measures. Using these results we prove existence of optimal controls for Bolza problems. Based on this result we present necessary conditions of optimality.