• The Journal of the Korea Contents Association
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• v.8 no.4
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• pp.86-91
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• 2008

To present the design procedure of discretized 8-bit tent map executing the transformation of tent function which is one of the chaotic functions, first, the truth table of discretized tent map was written, and then according to the simplified Boolean algebra equations obtained from the truth table, the discretized map is implemented with the exclusive logic gate as a real hardware. The discretized tent map circuit which provides the feedback circuit for generating the period-8 states relevant to the 8-bit finite precision is also designed and presented in this paper. Furthermore, it might be used stream cipher system with a new key-stream circuit for generate of chaotic binary sequence.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 1993.06a
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• pp.865-868
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• 1993

This paper describes a simple random signal generator employing by CMOS analog technology in current mode. The system is a nonlinear dynamical system described by a difference equation, such as x(t＋1) = f(x(t)) , t = 0,1,2, ... , where f($.$) is a nonlinear function of x(f). The tent map is used as a nonlinear function to produce the random signals with the uniform distribution. The prototype is implemented by using transistor array devices fabricated in a mass product line. It can be easily realized on a chip. Uniform randomness of the signal is examined by the serial correlation test and the $\chi$2 test.

• Communications of the Korean Mathematical Society
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• v.10 no.4
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• pp.881-887
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• 1995

Let f be a measurable function on the unit ball B in $C^n$, then we define a maximal function $M_p(f), 1 \leq p < \infty$, by $$ M_p(f)(\zeta ) = \sup_{\delta > 0}(\frac{1}{\sigma(\beta(\zeta, \delta))} \int_{T(\beta(\zeta, \delta))} $\mid$f(z)$\mid$^p \frac{d\nu(z)}{(1-$\mid$z$\mid$^n})^{1/p} $$ where $\sigma$ denotes the surface area measure on S, the boundary of B, and $T(\beta(\zeta, \delta))$ denotes the tent over the ball $\beta(\zeta, \delta)$. We prove that the maximal operator $M_p$ belongs to the Muckenhoupt class $A_1$.

• International Journal of Contents
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• v.11 no.4
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• pp.56-69
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• 2015

This paper proposes an efficient image encryption scheme based on quintuple encryption using two chaotic maps. The encryption process is realized with quintuple encryption by calling the encrypt(E) and decrypt(D) functions five times with five different keys in the form EDEEE. The decryption process is accomplished in the reverse direction by invoking the encrypt and decrypt functions in the form DDDED. The keys for the quintuple encryption/decryption processes are generated by using a Tent map. The chaotic values for the encrypt/decrypt operations are generated by using a Gumowski-Mira map. The encrypt function E is composed of three stages: permutation, pixel value rotation and diffusion. The permutation stage scrambles all the rows and columns to chaotically generated positions. This stage reduces the correlation radically among the neighboring pixels. The pixel value rotation stage circularly rotates all the pixels either left or right, and the amount of rotation is based on chaotic values. The last stage performs the diffusion four times by scanning the image in four different directions: Horizontally, Vertically, Principal diagonally and Secondary diagonally. Each of the four diffusion steps performs the diffusion in two directions (forward and backward) with two previously diffused pixels and two chaotic values. This stage ensures the resistance against the differential attacks. The security and performance of the proposed method is investigated thoroughly by using key space, statistical, differential, entropy and performance analysis. The experimental results confirm that the proposed scheme is computationally fast with security intact.

• Honam Mathematical Journal
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• v.42 no.4
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• pp.681-699
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• 2020

In this paper, topological entropy of iterated function systems (IFS) on one dimensional spaces is considered. Estimation of an upper bound of topological entropy of piecewise monotone IFS is obtained by open covers. Then, we provide a way to calculate topological entropy of piecewise monotone IFS. In the following, some examples are given to illustrate our theoretical results. Finally, we have a discussion about the possible applications of these examples in various sciences.

• The Journal of the Korea institute of electronic communication sciences
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• v.9 no.10
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• pp.1145-1152
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• 2014

The RFID (Radio-Frequency Identification) system is a technology to discern things by radio and an epoch-making new method to improve product management such as distribution, transport, mobilization, inventory control. However, RFID, which uses radio, is at risk for information leakage and falsification due to the vulnerability of security of the communication section. We designed the new authentication protocol by applying the tent map, which is the representative complex systems, to the RFID communication system. A more solid and simple authentication system was designed by applying the initial value sensitivity and irregularity, which are the representative characteristics of the complex system, to the reader and tag of RFID. The purpose of this paper is to verify the usability of the RFID authentication protocol design that uses the nonlinear system shown in this thesis by the new system differentiated from the authentication system that depends on the existing hash function or random numbers.

• Journal of Advanced Navigation Technology
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• v.17 no.3
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• pp.292-297
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• 2013

In this paper, The design of digital circuits for chaotic composition function which is used for the key-stream generator is studied in this work. The overall design concept and procedure due to the mathematical model of chaotic key-stream generator is to be the explained in detail, and also the discretized truth table of chaotic composition function is presented in this paper. consequently, a composition state machine based on the compositive map with connecting two types of one dimensional and two dimensional chaotic maps together is designed and presented.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38A no.8
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• pp.629-637
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• 2013

Chaos communication systems have the characteristics such as non-periodic, wide-band, non-predictability of signals and easy implementation. There have been many studies about chaos communication systems because of these advantages. But, chaos communication systems have low BER(Bit Error Rate) compare to general digital communication system. Existing researches on chaos communication systems only analyze BER performance according to various chaos maps. There are no studies on analysis of BER performance according to PDF(Probability Density Function) of chaos maps. In this paper, we analyze the BER performance according to changing parameter, equation, and initial values of chaos map's PDF. In addition, we propose new chaos map to improve BER performance. Simulation results show that BER performance of CDSK(Correlation Delay Shift Keying) is changed when PDF of chaos map changed. And the proposed chaos map has a better BER performance compare to previous chaos maps such as Tent map, Logistic map, and Henon map.

• Journal of Ginseng Research
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• v.19 no.3
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• pp.275-280
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• 1995

The formation of thylakoid membrane proteins and changes in the chloroplast ultrastructure of ginseng leaf were investigated as a function of time following the leaf emergence. The leaf chloroplast obtained just after the leaf emergence showed short rod-like thylakoids which were connected and arranged in 3~4 layers along the longitudinal axis of the chloroplast. The 10 DAE (days after emergence) chloroplast started to form grana structure. The typical grana structure was observed 17 DAE, and the grana was fully developed 28 DAE. The membrane proteins obtained from just after emerging leaf were separated into many minor bands indicating no CP-complex formation yet. LHC II was detected after 10 days. CP 47 and CP 43 were detected after 17 days. After 28 days, the PS I and PS II proteins were distinctly separated into CP 1, LHC II, CP 47, CP 43, CP 29, CP 27+24. Thus, the appearance of the light harvesting protein, LHC II, which was concentrated in grana stacks, was consis tent in time with the formation of grana stacks 17 DAE. Key words Chloroplast ultrastructure, grana, CP-complex, LHC II.

• Korean Journal of Construction Engineering and Management
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• v.18 no.6
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• pp.57-64
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• 2017

Recently, the disaster situation has been diversified and compounded worldwide as well as in Korea. And the damage scale of each disasters have increased, and following economic loss is also increasing immensely. In Korea, especially the out break frequency of large-scale disasters has increased. Disasters caused by earthquakes are also very likely to occur. When a major accident such as Mauna resort collapse accident, Ferry sewol sinking accident occurred, systematic emergency medical care at the site at the time of disaster occurred in order to operate an emergency medical facility corresponding to the site, which is not systematic. The need for this service is urgent. If highly reliable emergency medical system function at appropriate times in the disaster site, secondary damage can be reduced and the whole situation would be back to normal shortly. Therefore, it is necessary to provide an emergency medical system capable of quickly and safely responding to disaster sites in relation to various damage scale. For the purpose, thorough analysis on mobile medical units of inside and outside the country was accomplished. As a result, Mobile Medical Unit of outside the country are trailer type, tent type, container type etc. At home, these types have been studied and will be proposed early next year as a temporary solution. Here we introduce suitable types for our country.