• Journal of applied mathematics & informatics
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• v.19 no.1_2
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• pp.203-214
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• 2005

In this study the optimal control of fed-batch glycerol fermentation is investigated based on an impulsive dynamical system. Considering the sudden increase of the glycerol and alkali in fed-batch culture of biodissimilation of glycerol to 1,3-propanediol, this paper proposes a non-linear impulsive system of fed-batch culture. The existence, uniqueness and regularity properties of piecewise solution for the system are proved. In view of the controllability of volumes of glycerol added to the reactor instantaneously, the paper constructs an optimal control model based on the nonlinear impulsive system and the existence of the optimal control is obtained. The control variables here are the moments and the sizes of jumps in the states at the discrete instants and the objective is to maximize the productivity of 1,3-propanediol over one cycle.

• Proceedings of the Korean Society of Computer Information Conference
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• 2022.07a
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• pp.697-699
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• 2022

Based on the integrated analysis of the existing literature, this study combined with S-O-R model to explore the impact of e-commerce live broadcast characteristics on consumers' impulse purchase intention. Among them, interactive, entertaining, economical and visual features are selected as the features of e-commerce live broadcast; Select pleasure and arousal to measure consumer sentiment, and build a theoretical model among e-commerce live broadcast features, consumer sentiment and consumers' impulsive purchase intention to specifically explore the impact of each feature on emotion and the further impact of emotion on impulsive purchase intention.

• Honam Mathematical Journal
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• v.30 no.3
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• pp.521-533
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• 2008

We investigate a periodically forced Lotka-Volterra type predator-prey system with impulsive perturbations - seasonal effects on the prey, periodic releasing of natural enemies(predator) and spraying pesticide at the same fixed times. We show that the solutions of the system are bounded using the comparison theorems and find conditions for the stability of a stable prey-free solution and for the permanence of the system.

• The Journal of Information Systems
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• v.21 no.3
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• pp.117-136
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• 2012

Given to the prevalence of social commerce such as Groupon, Ticketmonster, and Coupang, it has become critical to understand customer purchasing behavior in social commerce environments. When consumers make purchasing decisions in social commerce, they often act impulsively. This is because social commerce is a deal-of-the-day website that features discounted gift certificates usable at local companies. However, the vast majority of social commerce research has viewed consumer decision-making as a rational process. This study develops a theoretical framework to investigate key drivers of customer's impulsive purchasing in social commerce. This study identifies flow, positive emotion, negative emotion, social commerce attractiveness, and discounted price as the key antecedents of impulsive purchasing. Data collected from 164 users who had prior purchasing experiences with social commerce were empirically tested against the research model using partial least squares analysis. The analysis results indicate that flow plays an important role in facilitating customers' impulsive purchasing in social commerce environments. Moreover, the findings show the exact roles of positive emotion, negative emotion, social commerce attractiveness, and discounted price on consumer's impulsive purchasing.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.20 no.12
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• pp.4036-4043
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• 1996

When a high-speed railway train enters a tunnel, a compression wave is generated ahead of the train and propagates along the tunnel, compressing and accelerating the rest air in front of the wave. At the exit of the tunnel, an impulsive wave is emitted outward toward the surrounding, which causes a positive impulsive noise like a kind of sonic boom produced by a supersonic aircraft. With the advent of high-speed train, such an impulsive noise can be large enough to cause the noise problem, unless some attempts are made to alleviate its pressure levels. In the purpose of the impulsive noise reduction, the present study tested the effect of porous walls on the compression wave propagating into a model tunnel. Experimental results were obtained using a shock tube with an open end. The results showed that the cavity/porous wall is very effective for the compression wave with a large nonlinear effect. The porosity of 30% is most effective for attenuation and pressure gradient reduction of the compression wave front. Also the impulsive noise reduction increases with increasing the length and height of the cavity, compared with the tunnel equivalent diameter.

• The Journal of Information Systems
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• v.31 no.4
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• pp.209-232
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• 2022

Purpose In the current environment of online shopping, the cost for consumers to obtain the information they need is decreasing, and the price of products is becoming more transparent, leading to increased price competition among enterprises for similar products. Given the widespread usage of limited-time promotion as a marketing method for enterprises in the context of e-commerce, it is great meaning to study and reveal the internal influence mechanism of limited-time promotion on consumers' impulsive consumption. Design/methodology/approach Based on the S-O-R theory, this study constructs a model of consumers' impulsive consumption in the context of e-commerce from the perspective of perceived price discount, with evoking sense and pleasure as mediating variables and perceived time pressure as moderating variables. Findings The results show that perceived price discount has a significant positive impact on evoking sense and pleasure. Evoking sense has a significant positive impact on pleasure. Both evoking sense and pleasure have a significant positive impact on consumers' impulsive consumption. Meanwhile, perceived time pressure plays a significant moderating role between perceived price discount and evoking sense, between perceived price discount and pleasure, and between evoking sense and consumers' impulsive consumption. Finally, based on the above findings, this study provides effective suggestions for e-commerce participants in the formulation of limited-time promotion strategies.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.17 no.4
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• pp.138-149
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• 2018

In this paper, we propose a system model which effectively mitigates impulsive noise that degrades the performance of power line communication. Recently, deep learning have shown effective performance improvement in various fields. In order to mitigate effective impulsive noise, we applied a convolution neural network which is one of deep learning algorithm to conventional system. Also, we used a successive interference cancellation scheme to mitigate impulsive noise generated from multi-users. We simulate the proposed model which can be applied to the power line communication in the Section V. The performance of the proposed system model is verified through bit error probability versus SNR graph. In addition, we compare ZF and MMSE successive interference cancellation scheme, successive interference cancellation with optimal ordering, and successive interference cancellation without optimal ordering. Then we confirm which schemes have better performance.

• Kyungpook Mathematical Journal
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• v.48 no.4
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• pp.593-611
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• 2008

Global attractivity and oscillatory behavior of the following nonlinear impulsive parabolic differential equation which is a general form of many population models $$\array{\{{{\frac {{\partial}u(t,x)}{{\partial}t}=\Delta}u(t,x)-{\delta}u(t,x)+f(u(t-\tau,x)),\;t{\neq}t_k,\\u(t^+_k,x)-u(t_k,x)=g_k(u(t_k,x)),\;k{\in}I_\infty,}\;\;\;\;\;\;\;\;(*)$$ are considered. Some new sufficient conditions for global attractivity and oscillation of the solutions of (*) with Neumann boundary condition are established. These results no only are true but also improve and complement existing results for (*) without diffusion or impulses. Moreover, when these results are applied to the Nicholson's blowflies model and the model of Hematopoiesis, some new results are obtained.

• YAKHAK HOEJI
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• v.59 no.4
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• pp.184-189
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• 2015

We compared impulsive behaviors in Wistar rats and in Wistar-Kyoto rats. There was no significant difference in locomotor activity between them. However, Wistar rats showed high activity in 5-choice serial reaction time track. When Wistar rats were treated with atomoxetin (3 mg/kg), methylphenidate (2 mg/kg) or amphetamine (2 mg/kg), they showed less impulsive behavior. Serotonin contents in prefrontal cortex and brain stem also increased. In conclusion, we suggest that Wistar rats could be used as animal model for impulsive behavior analysis. In addition, serotonin might be related with this impulsivity.

• Journal of the Korean Mathematical Society
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• v.44 no.2
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• pp.327-342
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• 2007

In this paper, a kind of pest-predator model with impulsive effect and infinite delay is considered by the method of chain transform. By using Floquet's theorem, it is shown that there exists a globally asymptotically stable periodic pest eradication solution when the impulsive period is less than or equal to some critical value which is a directly proportional function with respect to the population of release. Furthermore, it is proved that the system is permanent if the impulsive period is larger than some critical value. Finally, the results of the corresponding systems are compared, those results obtained in this paper are confirmed by numerical simulation.