Search Results

Now showing 1 - 5 of 5

Some of the metrics are blocked by your
consent settings
Adaptive pixel-selection using chaotic map lattices for image cryptography
(2014-02-24)
Sittigorn, Jirasak
;
Paithoonwattanakij, Kitti
;
Surawatpunya, Charray
Chaotic theory has been used in cryptography application for generating a sequence of data that is close to pseudorandom number based on an adjusted initial condition and a parameter. However, data recovery becomes a crucial problem due to the precision of the parameters. This difficulty leads to limited usage of Chaotic-based cryptography especially for error sensitive applications such as voice cryptography. In order to enhance the encryption security and overcome this limitation, an Adaptive Pixel-Selection using Chaotic Map Lattices (APCML) is proposed. In APCML, the encryption sequence has been adaptively selected based on chaos generator. Moreover, the chaotic transformation and normalization boundary have been revised to alleviate the rounding error and inappropriate normalization boundary problems. In the experiments, the measurement indices of originality preservation, visual inspection, and statistical analysis are used to evaluate the performance of the proposed APCML compared to that of the original CML. Consequently, the APCML algorithm offers greater performance with full recovery of the original message. © 2014 Copyright SPIE.
Some of the metrics are blocked by your
consent settings
CMOS-based integrable electronically tunable floating general impedance inverter
(1997-01-01)
Surakampontorn, Wanlop
;
Kumwachara, Kiattisak
;
Riewruja, Vanchai
;
Surawatpunya, Charray
An integrable electronically tunable general impedance inverter (EGII), implemented by a MOS circuit design technique, is described. The driving point impedance of the EGII, that is inversely proportional to a given impedance, can be a positive or a negative value and can be electronically varied. The realization scheme employs proposed voltage-to-current transducers (VCTs) that are designed based on a linearizing technique, as basic circuit building blocks. The applications of the EGII as a gyrator, a general impedance converter and a floating capacitance multiplier are discussed. Experimental and simulation results that demonstrate the characteristics of the EGII are included. © 1997 Taylor and Francis Group, LLC.
Some of the metrics are blocked by your
consent settings
Instrumentation amplifiers using operational transconductance amplifiers
(1991-01-01)
Surakampontorn, Wanlop
;
Riewruja, Vanchai
;
Surawatpunya, Charray
;
Yodladda, Suwan
Instrumentation amplifier circuits using operational transconductance amplifiers (OTAs) as active circuit elements are proposed in this paper. Two new instrumentation amplifier circuits have been described and experimentally verified, where the first circuit comprises four OTAs and five resistors and the second circuit comprises two OTAs and three resistors. © 1991 Taylor & Francis, Ltd.
Some of the metrics are blocked by your
consent settings
Microstrip waveguide gunn oscillator
(1989-01-01)
Surawatpunya, Charray
;
Saetang, Khanittha
A microstrip waveguide Gunn oscillator is proposed. The oscillator utilizes frequency-selective feedback from the periodic structures created in the microstrip waveguide to the Gunn diode to achieve stable oscillation. An oscillator design by means of an equivalent-circuit model is described. The observed oscillation characteristics of an X-band microstrip waveguide Gunn oscillator are reported. © 1989 Taylor & Francis Ltd.
Some of the metrics are blocked by your
consent settings
Bragg Interaction of Electromagnetic Waves in a Ferrite Slab Periodically Loaded with Metal Strips
(1984-01-01)
Surawatpunya, Charray
;
Tsutsumi, Makoto
;
Kumagai, Nobuaki
The waveguiding characteristics of electromagnetic TE waves in a ferrite slab periodically loaded with metal strips are investigated. Theoretical formulation by means of the spectral domain approach is employed to obtain the Brillouin diagrams of two types of volume modes and a surface mode. It is found that the nonreciprocal properties of waves depend on the metal strip profile and bias magnetic field strength. Experiments on the magnetic-field dependence of the Bragg frequency and the stop bandwidth are carried out in the millimeter-wave frequencies. Typical results obtained from a polycrystalline YIG slab with periodic gold strips deposited on one surface are: stop bandwidth about 2.14 GHz, with return loss about 2 dB at the Bragg frequency of 47.5 GHz, for the bias magnetic-field strength of 5.7 kG.The Bragg frequency can be tuned over the range of 1.39 GHz by varying the bias magnetic field from 0 to 8.2 kG. Experimental results show good agreement with theoretical predictions. © 1984 IEEE

KMITL

Browse

Filters

Settings

Sort By

Results per page

Search Results