• Title/Summary/Keyword: Memory decay

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ON UNIFORM DECAY OF WAVE EQUATION OF CARRIER MODEL SUBJECT TO MEMORY CONDITION AT THE BOUNDARY

  • Bae, Jeong-Ja;Yoon, Suk-Bong
    • Journal of the Korean Mathematical Society
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    • v.44 no.4
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    • pp.1013-1024
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    • 2007
  • In this paper we consider the uniform decay for the wave equation of Carrier model subject to memory condition at the boundary. We prove that if the kernel of the memory decays exponentially or polynomially, then the solutions for the problems have same decay rates.

Fractional radioactive decay law and Bateman equations

  • Cruz-Lopez, C.A.;Espinosa-Paredes, G.
    • Nuclear Engineering and Technology
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    • v.54 no.1
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    • pp.275-282
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    • 2022
  • The aim of this work is to develop the fractional Bateman equations, which can model memory effects in successive isotopes transformations. Such memory effects have been previously reported in the alpha decay, which exhibits a non-Markovian behavior. Since there are radioactive decay series with consecutive alpha decays, it is convenient to include the mentioned memory effects, developing the fractional Bateman Equations, which can reproduce the standard ones when the fractional order is equal to one. The proposed fractional model preserves the mathematical shape and the symmetry of the standard equations, being the only difference the presence of the Mittag-Leffler function, instead of the exponential one. This last is a very important result, because allows the implementation of the proposed fractional model in burnup and activation codes in a straightforward way. Numerical experiments show that the proposed equations predict high decay rates for small time values, in comparison with the standard equations, which have high decay rates for large times. This work represents a novelty approach to the theory of successive transformations, and opens the possibility to study properties of the Bateman equation from a fractional approach.

GLOBAL EXISTENCE AND STABILITY FOR EULER-BERNOULLI BEAM EQUATION WITH MEMORY CONDITION AT THE BOUNDARY

  • Park, Jong-Yeoul;Kim, Joung-Ae
    • Journal of the Korean Mathematical Society
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    • v.42 no.6
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    • pp.1137-1152
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    • 2005
  • In this article we prove the existence of the solution to the mixed problem for Euler-Bernoulli beam equation with memory condition at the boundary and we study the asymptotic behavior of the corresponding solutions. We proved that the energy decay with the same rate of decay of the relaxation function, that is, the energy decays exponentially when the relaxation function decay exponentially and polynomially when the relaxation function decay polynomially.

ENERGY DECAY FOR A VISCOELASTIC EQUATION WITH BALAKRISHNAN-TAYLOR DAMPING INVOLVING INFINITE MEMORY AND NONLINEAR TIME-VARYING DELAY TERMS IN DYNAMICAL BOUNDARY

  • Soufiane Benkouider;Abita Rahmoune
    • Communications of the Korean Mathematical Society
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    • v.38 no.3
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    • pp.943-966
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    • 2023
  • In this paper, we study the initial-boundary value problem for viscoelastic wave equations of Kirchhoff type with Balakrishnan-Taylor damping terms in the presence of the infinite memory and external time-varying delay. For a certain class of relaxation functions and certain initial data, we prove that the decay rate of the solution energy is similar to that of relaxation function which is not necessarily of exponential or polynomial type. Also, we show another stability with g satisfying some general growth at infinity.

EXPONENTIAL DECAY FOR THE SOLUTION OF THE VISCOELASTIC KIRCHHOFF TYPE EQUATION WITH MEMORY CONDITION AT THE BOUNDARY

  • Kim, Daewook
    • East Asian mathematical journal
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    • v.34 no.1
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    • pp.69-84
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    • 2018
  • In this paper, we study the viscoelastic Kirchhoff type equation with a nonlinear source for each independent kernels h and g with respect to Volterra terms. Under the smallness condition with respect to Kirchhoff coefficient and the relaxation function and other assumptions, we prove the uniform decay rate of the Kirchhoff type energy.

Write-in and Retention Characteristics of Nonvolatile MNOS Memory Devices (비휘발성 MNOS기억소자의 기억 및 유지특성)

  • 이형옥;강창수;이상배;서광열
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 1991.10a
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    • pp.44-47
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    • 1991
  • Electron injection and memory retention chracteristics of the MNOS devices with thin oxide layer of 23${\AA}$ thick and silicon nitride layer of 1000${\AA}$ thick which are fabricated for this experiment. As a result, pulse amplitude increase oxide current is dominated in linearly increasing region of $\Delta$V$\_$FB/the decreasing region after saturation was due to the increased silicon nirtide current. In low pulse ampiltude $\Delta$V$\_$FB/ is not variated on temperature, but as temperature and pulse amplitude increase. $\Delta$V$\_$FB/ is decreased after saturation. And the decay rate during 10$^4$sec after electron injection was ohiefly dominated by the back tunneling of emission from memory trap to silicon. Memory retention characteristics in V$\_$FB/ stage was better than that of OV retention regardless of injection conditions.

Selective Inference in Modular Bayesian Networks for Lightweight Context Inference in Cell Phones (휴대폰에서의 경량 상황추론을 위한 모듈형 베이지안 네트워크의 선택적 추론)

  • Lee, Seung-Hyun;Lim, Sung-Soo;Cho, Sung-Bae
    • Journal of KIISE:Software and Applications
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    • v.37 no.10
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    • pp.736-744
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    • 2010
  • Log data collected from mobile devices contain diverse and meaningful personal information. However, it is not easy to implement a context-aware mobile agent using this personal information due to the inherent limitation in mobile platform such as memory capacity, computation power and its difficulty of analysis of the data. We propose a method of selective inference for modular Bayesian Network for context-aware mobile agent with effectiveness and reliability. Each BN module performs inference only when it can change the result by comparing to the history module which contains evidences and posterior probability, and gets results effectively using a method of influence score of the modules. We adopt memory decay theory and virtual linking method for the evaluation of the reliability and conservation of casual relationship between BN modules, respectively. Finally, we confirm the usefulness of the proposed method by several experiments on mobile phones.

Cold Boot Attack on Encrypted Containers for Forensic Investigations

  • Twum, Frimpong;Lagoh, Emmanuel Mawuli;Missah, Yaw;Ussiph, Najim;Ahene, Emmanuel
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.16 no.9
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    • pp.3068-3086
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    • 2022
  • Digital Forensics is gaining popularity in adjudication of criminal cases as use of electronic gadgets in committing crime has risen. Traditional approach to collecting digital evidence falls short when the disk is encrypted. Encryption keys are often stored in RAM when computer is running. An approach to acquire forensic data from RAM when the computer is shut down is proposed. The approach requires that the investigator immediately cools the RAM and transplant it into a host computer provisioned with a tool developed based on cold boot concept to acquire the RAM image. Observation of data obtained from the acquired image compared to the data loaded into memory shows the RAM chips exhibit some level of remanence which allows their content to persist after shutdown which is contrary to accepted knowledge that RAM loses its content immediately there is power cut. Results from experimental setups conducted with three different RAM chips labeled System A, B and C showed at a reduced temperature of -25C, the content suffered decay of 2.125% in 240 seconds, 0.975% in 120 seconds and 1.225% in 300 seconds respectively. Whereas at operating temperature of 25℃, there was decay of 82.33% in 60 seconds, 80.31% in 60 seconds and 95.27% in 120 seconds respectively. The content of RAM suffered significant decay within two minutes without power supply at operating temperature while at a reduced temperature less than 5% decay was observed. The findings show data can be recovered for forensic evidence even if the culprit shuts down the computer.