• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2021.10a
• /
• pp.140-142
• /
• 2021

Mobile communication technology after 5th generation requires high speed, hyper-connection, and low latency communication. In order to meet technical requirements for secure hyper-connectivity, low-spec IoT devices that are considered the end of IoT services must also be able to provide the same level of security as high-spec servers. For the purpose of performing these security functions, it is required for cryptographic keys to have the necessary degree of stability in cryptographic algorithms. Cryptographic keys are usually generated from cryptographic random number generators. At this time, good noise sources are needed to generate random numbers, and hardware random number generators such as TRNG are used because it is difficult for the low-spec device environment to obtain sufficient noise sources. In this paper we used the chip which is based on quantum characteristics where the decay of radioactive isotopes is unpredictable, and we presented a variety of methods (TRNG) obtaining an entropy source in the form of binary-bit series. In addition, we conducted the NIST SP 800-90B test for the entropy of output values generated by each TRNG to compare the amount of entropy with each method.

• The Journal of the Acoustical Society of Korea
• /
• v.43 no.3
• /
• pp.361-367
• /
• 2024

Ultrasound in the air is widely used in industry as a measurement technique to prevent abnormalities in the machinery. Recently, the use of airborne ultrasound imaging techniques, which can find the location of abnormalities using an array transducers, is increasing. A beamforming method that uses the phase difference for each sensor is used to visualize the location of the ultrasonic sound source. We exploit a random sparse ultrasonic array and obtain beamforming power distribution on the source in a certain distance away from the array. Conventional beamforming methods inevitably have limited spatial resolution depending on the number of sensors used and the aperture size. A high-resolution ultrasound imaging technique was implemented by applying functional beamforming as a method to overcome the geometric constraints of the array. The functional beamforming method can be expressed as a generalized beam forming method mathematically, and has the advantage of being able to obtain high-resolution imaging by reducing main-lobe width and side lobes. As a result of observation through computer simulation, it was verified that the resolution of the ultrasonic source in the air was successfully increased by functional beamforming using the ultrasonic sparse array.

• Journal of the Institute of Electronics and Information Engineers
• /
• v.52 no.12
• /
• pp.109-117
• /
• 2015

In this paper, we proposed error-reducing method to source or measure a current or voltage for LED in the I-V characteristic analysis system using a digital signal processor (DSP). this method has the advantage of reducing a non-linear circuit error and random error. random error can be reduced using recursive averaging technique and non-linear circuit error can be reduced using 2rd polynomial regression calibration parameters fitting with measured sample data. it corrects measured error of IR, VR, VF1, VF2, VF3 of LED using calibration parameters. experimental results show that can be performed with about 0.017~0.043% accuracy.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
• /
• 2005.11a
• /
• pp.161-165
• /
• 2005

In this paper, we observed degradation characteristics of luminous flux for new light source. Because degradation tests can be a useful tool for assessing the reliability when few or even no failures are expected in a life tests. And we use a simple random coefficient degradation model to induce most suitable equation of degradation. As a result, exponential distribution and equation is best suitable model for new light source.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2010.05a
• /
• pp.425-426
• /
• 2010

Recently, Most of diverse noise of vehicles has decreased competitively according to development of the automotive manufacturing technology. Especially, Passenger car manufacturers has been conducting buzz, squeak and rattle(BSR) noise test as a method of the noise evaluation tests to reduce an unpleasant sound from interior parts on the driving the car. This paper suggest a evaluation method for detecting position of noise source from measured noise signals of vehicle seats during random excitation BSR test. Hereby the BSR test procedure used the test regulation of 'G' company. The detection of noise source positions used the Sound image equipment. Through suggested the test method on this paper, an accurate analysis of noise source occurred in the BSR test will be possible.

• Korean Journal of Optics and Photonics
• /
• v.10 no.5
• /
• pp.396-400
• /
• 1999

In the fiber-optic gyroscope employing a high-power erbium-doped fiber source, the source excess noise was subtracted from the gyro output through a single processing to improve the gyroscope sensitivity. As the result, we obtained the reduction of noise by 13.5 dB (electrical) which was measured from the noise floor spectrum when the gyro was modulated with the depth of 1.8 rad. In addition, the random walk coefficient of the gyro output was reduced by a factor of 4~5.

• 한국지구물리탐사학회:학술대회논문집
• /
• 2007.06a
• /
• pp.81-86
• /
• 2007

Spectral features of the seismic wave propagation from Odaesan Earthquake were evaluated based on the commonly treated random error between the observed data and the prediction values by the stochastic point-source ground-motion spectral model regarding the source, path and site effects. Radiation pattern of the error according to azimuth angle was found to be similar to the theoretical estimate. It was also observed that the spatial distribution of the errors was correlated with the geological map and the Q0 map which are indicatives of seismic boundaries.

• The Journal of Korean Medicine
• /
• v.39 no.1
• /
• pp.44-54
• /
• 2018

Objectives: The objective of this study is to investigate the effects of drinking alcohol on bio-electrical potential at twelve source points. Methods: Twenty healthy adults were assigned to alcohol and water groups by a random cross-over design. Bio-electrical potential at twelve source points were measured before and after drinking alcohol or water and the change of bio-electrical potential was analyzed and compared between the alcohol and the water groups. Results: Bio-electrical potential at LI4, ST42, KI3, PC7, TE4, GB40, LR3 in the alcohol group was significantly increased compared to those in the water group. Conclusions: Drinking alcohol increased bio-electrical potential at source points of LI, ST, KI, PC, TE, GB and LR in healthy human subjects.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.42 no.2
• /
• pp.307-315
• /
• 2017

Random number generator(RNG) is essential in cryptographic applications. As recently a system using small devices such as IoT, Sensor Network, SmartHome appears, the lightweight cryptography suitable for this system is being developed. However due to resource limitations and difficulties in collecting the entropy, RNG designed for the desktop computer are hardly applicable to lightweight environment. In this paper, we propose a lightweight RNG to produce cryptographically strong random number using sensors. Our design uses a Hankel matrix, block cipher as the structure and sensors values as noise source. Futhermore, we implement the lightweight RNG in Arduino that is one of the most popular lightweight devices and estimate the entropy values of sensors and random number to demonstrate the effectiveness and the security of our design.

• Journal of electromagnetic engineering and science
• /
• v.9 no.3
• /
• pp.130-140
• /
• 2009

The design theory and experimental results of a true random noise radar system are presented in this paper. Target range information can be extracted precisely by correlation processing between the delayed reference and the signal received from a target, and the velocity information by the Doppler processing with successive correlation data. A K-band noise radar system was designed using random FM noise signal, and the characteristics of the fabricated system were examined with laboratory and outdoor experiments. A C-band random FM noise signal was generated by applying a low-frequency white Gaussian noise source to VCO(Voltage Controlled Oscillator), and a K-band Tx noise signal with 100 MHz bandwidth was obtained by using a following frequency multiplier. Two modified wave-guide horn arrays were designed and fabricated, and used for the Tx and Rx antennas. The required amount of Tx/Rx isolation was attained by using a coupling cancellation circuit as well as keeping them apart with predetermined spacing. A double down-conversion scheme was used in the Rx and reference channels, respectively, for easy post processing such as correlation and Doppler processing. The implemented noise radar performance was examined with a moving bicycle and a very high-speed target with a velocity of 150 m/s. The results extracted by the Matlab simulation using the logging data were found to be in a reasonable agreement with the expected results.