• Journal of the Korean Society for Precision Engineering
• /
• v.28 no.10
• /
• pp.1141-1145
• /
• 2011

Recently, there are many issues about R2R printing technique for mass production of electronic devices. Among the various Roll-to-roll based printing techniques such as gravure, off-set, flexo and so on, "Gravure off-set printing technique" has an advantage of higher printing resolution. The printing unit of gravure off-set printing technique usually consists of plate roll, blanket roll and impressure roll whose. Linear velocities should be synchronized each other for fine pattern printing. However, roller's manufacturing error and printing variations such as pringting pressure, printing speed, roll stroke and so on actually affected their synchronization anf thus the quality of fine fattern. In this paper, we analyzed the effective of synchronization error on printing quality. Also, this paper reviews the relative motion with each roll. And, this paper studys the synchronization error about its generation problem.

• Nuclear Engineering and Technology
• /
• v.51 no.3
• /
• pp.683-691
• /
• 2019

In this paper, we propose a novel method to quantify the neural synchronization between subjects in the collaborative process through electroencephalogram (EEG) hyperscanning. We hypothesized that the neural synchronization in EEGs will increase when the communication of the operators is smooth and the teamwork is better. We quantified the EEG signal for multiple subjects using a representative EEG quantification method, and studied the changes in brain activity occurring during collaboration. The proposed method quantifies neural synchronization between subjects through bispectral analysis. We found that phase synchronization between EEGs of multi subjects increased significantly during the periods of collaborative work. Traditional methods for a human error analysis used a retrospective analysis, and most of them were analyzed for an unspecified majority. However, the proposed method is able to perform the real-time monitoring of human error and can directly analyze and evaluate specific groups.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
• /
• v.8 no.1
• /
• pp.12-17
• /
• 2015

This paper describes an error synchronization running on IP-USN gateway software stack for transportation safety service. This system consists of an TS_EDA, and TS_ESA. TS_EDA is an agent that detects an error for multimedia distance system based on IP-USN gateway software stack environment. TS_ESA is an agent that is an error synchronization system for multimedia distance control based on IP-USN gateway software stack environment. From the perspective of multimedia collaborative environment of IP-USN gateway software stack for transportation safety service, an error application becomes another interactive presentation error is synchronized with participants engaged in a cooperative work.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.38C no.2
• /
• pp.141-154
• /
• 2013

The technology of precise time-synchronization between signal receive devices for separation distance operation can be a key point for the technology with TDoA-based system. We propose a new method for the higher accuracy of system's time-synchronization in this paper, which uses OCXO and DPLL with high accuracy to achieve phase synchronization at 1 pps (pulse per second) of signal. And the method receive time value from a GPS satellite. Essentially, the performance of GPS with high accuracy refers to long-term frequency stability for its reliability. As per the characteristic, as the GPS timing signals are synchronized continuously, the accuracy of time-synchronization gets improved proportionally. Therefore, if the time synchronization is accomplished, the accuracy of the synchronization can be up to 0.001 ppb (part per billion). Through the improved accuracy of the time-synchronization, the measurement error of TDOA-based location detection technology is evaluated. Consequently, we verify that TDoA-based location measurement error can be greatly improved via using the improved method for time-synchronization error.

• Journal of electromagnetic engineering and science
• /
• v.5 no.1
• /
• pp.26-30
• /
• 2005

It is important to know phase offsets of PN(Pseudo Noise) sequences in spread spectrum communications since the acquisition is equivalent to making a phase offset between a receiving PN sequence and a PN sequence of local PN generator be identical. In this paper, a phase offset enumeration method for PN sequences with error detection, and its application to the synchronization are proposed. The phase offset enumeration for an n-tuple PN sequence and its error detection are performed when one period of the sequence is received. Once the phase offset of the receiving sequence is calculated, we can easily accomplish the synchronization by initializing shift registers of a local PN generator according to the phase offset value. The mean acquisition time performance of the proposed scheme was derived analytically. Since this synchronization scheme can be realized by using simple circuit and acquires very rapid acquisition in high SNR but shows performance degradation in low SNR, it can be especially useful in indoor and office environments.

• The KIPS Transactions:PartB
• /
• v.11B no.1
• /
• pp.45-52
• /
• 2004

We propose ESS_WMCE. This paper explains the design and implementation of the EDSS running on ESS_WMCE. EDSS is a synchronization error control system for web based multimedia collaboration environment. We have an error detection approach by using hooking method. The technique of an error transmission is a mended model of utilizing an application sharing system. DOORAE is a good framework model for supporting development on application for computer supported cooperated works. It has primitive service functions. Service functions are implemented with an object oriented concept. It is a system that is suitable for detecting and sharing a software error rapidly occurring on web based multimedia collaboration environment by using software techniques. It is able to share an error as well as providing URL synchronization to access shared objects. When an error occurs, this system detects an error by using hooking methods in MS-Windows API(Application Program Interface) function. If an error is found, it is able to provide an error sharing to access shared objects.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.27 no.1B
• /
• pp.79-89
• /
• 2002

A synchronization method is presented for IEEE 802.11a wireless OFDM system. First the coarse symbol synchronization is achieved by measuring the moving power average of the received envelope signal. The detection probabilities and optimum thresholds for the symbol synchronization are derived. By measuring the correlation between the short training signal and received envelope signal, fine symbol synchronization can be acquired. And the frequency synchronization is achieved using long training signal. A symbol synchronization error causes a phase rotation of the constellation. After the compensation for fading channel, the rotation due to the symbol timing error can be corrected. With this method, synchronization can be well achieved over frequency selective channels.

• Proceedings of the KIEE Conference
• /
• 2005.05a
• /
• pp.272-274
• /
• 2005

In this paper, we analyses transmission performance of communication security(COMSEC) bit synchronization information over the single channel found and airborne radion system in variable message format system. Experimental results demonstrate the robust characteristics of the COMSEC bit synchronization information in $10^{-1}\sim10^{-5}$ of bit error channel and the relationship of time duration of bit synchronization and probability of synchronization detection.

• Journal of Positioning, Navigation, and Timing
• /
• v.3 no.2
• /
• pp.71-81
• /
• 2014

Time synchronization system using dual frequency bands is designed and the error sources are analyzed for alternative synchronized-pseudolite navigation system (S-PNS) which aims at military application. To resolve near/far problem, dual frequency band operation is proposed instead of pulsing transmission which degrades level of reception. In dual frequency operation H/W delay should be considered to eliminate errors caused by inter-frequency bias (IFB) difference between the receivers of the pseudolites and users. When time synchronization is performed across the sea, multipath error is occurred severely since the elevation angle between pseudolites is low so total reflection can be happened. To investigate the difference of multipath effects according to location, pseudolites are set up coastal area and land area and performances are compared. The error source related with tropospheric delay is becoming dominant source as the coverage of the PNS is broadening. The tropospheric delay is measured by master pseudolite receiver directly using own pseudorange and slave pseudorange. Flight test is performed near coastal area using S-PNS equipped with developed time synchronization system and test results are also presented.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.35 no.6C
• /
• pp.572-579
• /
• 2010

Filtered multi-tone (FMT) is a form of multicarrier modulation utilizing frequency-domain equalization efficient in multi-path fading channels. Doppler frequency information can be employed for channel estimation and link adaptation to improve the performance. However, most previous studies have concentrated on the orthogonal frequency division multiplexing (OFDM) instead of FMT. Moreover, they have not considered the synchronization error that can commonly occur in practical systems. In this paper, we propose Doppler frequency estimation scheme that is effective in FMT systems with residual synchronization error and high noise levels.