• KSII Transactions on Internet and Information Systems (TIIS)
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• v.7 no.10
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• pp.2527-2543
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• 2013

A novel steganographic QR code algorithm, which not only coveys the secret into the widely-used QR barcode but also preserves the readability of QR content and the capability of error correction, is presented in this article. Different from the conventional applications for QR barcode, the designed algorithm conceals the secret into the QR modules directly by exploiting the error correction capability. General browsers can read the QR content from the QR code via barcode readers; however, only the authorized receiver can further reveal the secret from the QR code directly. The new mechanism can convey a larger secret payload along with adjustment of the QR version and error correction level. Moreover, the blind property allows the receiver to reveal the secret without the knowledge of the embedded position of modules. Experimental results demonstrate that the new algorithm is secure, efficient and feasible for the low-power QR readers and mobile devices.

• Journal of Korea Multimedia Society
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• v.7 no.2
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• pp.164-172
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• 2004

Halftoning of gray-scale image is a process to produce a binary image. The error diffusion halftoning method produces high qualify binary image but that has some defects such as sharpening and directional artifacts. We propose the threshold modulation to reduce such defects. The proposed algorithm uses thresholds reflecting local characteristic of image. We calculate thresholds which minimize errors of flat region of each gray-scale level by using a linear gain between original image and error-diffused image and then represent edge by compensating thresholds in proportion to edge information. The proposed method improves on halftone quality by minimizing an error which cause sharpening and directional artifact.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.15 no.10
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• pp.797-810
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• 1990

The error rate equations of digitally modulated signals transmitted through the Gaussian noise and tone multiple interference channel have been derived. Using the derived equations of error probabilities in the environments of Gaussian noise tone interferer and Gaussian noise multiple interferer, the error rate performances of various digitally modulated signals have been evaluated, and compared in graphs as a function of average carrier to tone interferer power ratio(CIR), average carrier to multiple interferer power ratio(CIT) and the average carrer-to-Gaussian noise powr ratio(CIR). In this paper, the modulation schemes such as amplitude shift keying (ASK), phase shift keying(PSK), frequency shift keying(FSK), minimum shift keying(MSK), quadrature amplitud modulation(QAM) and amplitude phase shift keying(APK) have been selected for the study of performance comparison. The results of comparison show us that, in low bits/sec/Hz, PSK is superior to the other schemes, but in high bits/sec/Hz, mixed multi ary type is better than single multi ary type. And in strong noise evironment, the multiple interferer has much influence than tone interferer, however, in low noise environment. the mojor error factor is tone interferer. But tone interference effect nearly disappears over specified CIR level about 20[dB]. And the modulation schemes using amplitude are heavily influenced by multiple interference.

• Journal of the Korea Institute of Military Science and Technology
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• v.18 no.2
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• pp.109-114
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• 2015

A method to compensate a bias hysteresis error of the ring laser gyro using the rate of temperature is proposed in this paper. Until now, we generally have measured and compensated the error of gyro and accelerometer using the temperature. However, we utilize the measured values of the temperature dependent error elements on the temperature rate in navigation system level. We show through experiments that the proposed method can improve the navigation performance and be very effective.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.3C
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• pp.133-140
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• 2005

This paper introduces a spatial error concealment technique using directional interpolation in block-based compression. The first step involves finding the spatial direction vectors represented an edge-direction in the lost block using spatial boundary matching algorithm. Then, the error blocks are recovered by directional interpolation through these vectors and concealed by using the recovered blocks which have lower directional boundary matching error out of them relatively. This proposed method is able to deal with errors on macroblock or slice level adaptively. And it has lower complexity and maintains better performance compared to the conventional methods.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.04a
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• pp.348-349
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• 2014

In general, there has been a lot of research concerned about the gear noise known to be proportional to gear transmission error for external gears likewise spur, helical gear, and hypoid gears. But, In the case of planetary gear set, gear noise study is insufficient because of the difficulty of designing, manufacturing, and understanding of the its mechanical system. This study is aimed to develop the transmission error measurement equipment for the planetary gear sets used in the automatic transmission. By comparing the results of the transmission error and noise objectively, user could select the optimized planetary gear set which has quiet noise level before manufacturing the automatic transmission.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.24 no.7
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• pp.549-554
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• 2014

In general, there has been a lot of research concerned about the gear noise known to be proportional to gear transmission error for external gears likewise spur, helical gear, and hypoid gears. But, In the case of planetary gear set, gear noise study is insufficient because of the difficulty of designing, manufacturing, and understanding of its mechanical system. This study is aimed to develop the transmission error measurement equipment for the planetary gear sets used in the automatic transmission. By comparing the results of the transmission error and noise objectively, user could select the optimized planetary gear set which has quiet noise level before manufacturing the automatic transmission.

• Journal of the Korean Society for Precision Engineering
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• v.32 no.2
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• pp.127-133
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• 2015

The error motion of a machine tool spindle directly affects the surface errors of machined parts. Those are usually due to the imperfectness of bearings, stiffness of spindle, assembly errors, external force or unbalance of rotors. The error motions of the spindle have been needed to be decreased to desired goal of spindle's performance. The level of error motion is needed to be estimated during the design and assembly process of the spindle. In this paper, the estimation method for the five degree of freedom (5 D.O.F) error motions for rotary units such as a spindle and rotary table are suggested. To estimate the error motions of the rotary unit, waviness of bearings and external force model were used as input data. The estimation model considers geometric relationship and force equilibrium of the five degree of the freedom motions.

• Phonetics and Speech Sciences
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• v.7 no.2
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• pp.29-38
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• 2015

This study explores reading fluency among elementary school students considering language level and family income(low SES). Forty eight students from 1st to 3rd grades participated in two paragraph reading tasks. Half of the children were from low income family and half of the children had low lexical knowledge. Reading fluency as in the number of correctly read syllables per minute, the total error frequency and error types were used to compare group differences. There were significant differences in the number of correctly read syllables per minute between two income groups and two language groups. There was a significant difference between low income group and non-low income group in total number of errors only when children's lexical knowledge were low. There were no group differences in error types of repetition and omission. Substitution and insertion error seemed to reflect the total error pattern. These results imply the importance of early screening and early involvement for children with low lexical knowledge from low income family. Monitoring and early intervention will support these children's reading development.

• The Journal of Asian Finance, Economics and Business
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• v.7 no.8
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• pp.747-752
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• 2020

This study examines cognitive impairment, which is one of the results from social exclusion and leads to logical reasoning disorders. This study also investigate how cognitive errors called abductive inference error occur due to cognitive impairment. Present study was performed with 81 college students. Participants were randomly assigned to the group who has experienced social exclusion or to the group who has not experience the social exclusion. We analyzed how the degree of error of abductive inference differs according to the social exclusion experience. The group who has experienced social exclusion showed a higher level of abductive inference error than the group who has not experience. The abductive condition inference value of the group who has experienced social exclusion was higher in the group with the deduction condition inference value of 90% than in the group with the deduction condition inference value of 10%, and the difference was also significant. This study extended the concepts of cognitive impairments, escape theory, cognitive narrowing which are used to explain addiction behavior to human cognitive bias. Also this study confirmed that social exclusion experience increased cognitive impairment and abductive inference error. Future research directions and implications were discussed and suggested.