• Korean Journal of Optics and Photonics
• /
• v.10 no.5
• /
• pp.405-412
• /
• 1999

We propose an effective algorithm, which can predict the detailed behavior of the intensity-modulated high speed optical signal after propagating through an optical fiber. The alogrithm is based on the SSF (Split Step Fourier) Method, however, the step size is automatically calibrated in each calculation step to reduce the number of calculations within given round-off error bound. Applying the algorithm to the 2.5 Gbps 100 km transmission and 10 Gbps 40 km transmission simulations, we achieved the calculation time reduction by maximum 1/120 and 1/56 of the calculation time by using the SSF fixed step algorithm previously known. The root-mean-square of the round-off error was kept within -30 dB compared to the signal level throughout the calculation.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.18 no.1
• /
• pp.47-56
• /
• 2008

This paper presents a detecting technique for the improvement in quality by appling the various vibrational characteristics theory. The object of this study is to objectively point out faulty gear by developing the program which can be used to analyze and predict the vibrational characteristics caused by gear wear, deformation and nick of auto-transmission. The fault detection methods by vibrational signal analysis of gear have been progressed in the various fields of industry. These methods have the advantage of being easy to attach the accelerometer without discontinuance of the structure. But not all the methods are efficient for finding early faults. So in the thesis, we completed development of the inspection system of vibration by appling the most efficient detecting methods and verified the system's reliability through experiments.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2016.10a
• /
• pp.712-714
• /
• 2016

The PS algorithm divides the tags within the identification range of reader into smaller groups by increasing the transmission power incrementally and identifies them. In 13.56MHz RFID system of Auto-ID center, STAC protocol is defined as an anti-collision algorithm for multiple tag reading. In this paper, we propose a STAC/PS algorithm that the PS algorithm is applied in the STAC protocol. The simulation results show that the STAC/PS algorithm can achieve faster tag identification speed compared with STAC protocol due to the low collision rate.

• Journal of Auto-vehicle Safety Association
• /
• v.14 no.1
• /
• pp.45-54
• /
• 2022

Recently, the introduction of Cooperative Intelligent Transport Systems (C-ITS) has been attempted to solve the limitation of only the sensor of the vehicle itself. For example, vehicles traveling at intersections can drive more safely through C-ITS. By using V2X communication of WAVE and LTE, the driver can receive the status and time of traffic lights. However, LTE has a larger transmission delay time than WAVE, so timimg data may not match in real time. In this paper, using the SPaT message, it was confirmed that LTE has a larger C-ITS service transmission delay time than WAVE. Finally, it was confirmed that the timing data of SPaT provided by LTE corrected by the algorithm is similar to SPaT provided by WAVE. It was confirmed that safer intersection driving is possible based on real-time.

• Journal of the Institute of Electronics Engineers of Korea SC
• /
• v.44 no.6
• /
• pp.49-56
• /
• 2007

In this paper, the development of excitation light source is proposed for excitation light of the photodynamic therapy of cancer. Since the selection of the wavelength band of excitation light has an interrelation with fluorescence generation according to the selection of a photosensitizer. This study aims at designing and evaluating light source that can stably generate light with various kinds of wavelengths in order to make possible photodynamic diagnosis using a photosensitizer and diagnosis using auto-fluorescence. The light source device was a Xenon lamp and filter wheel, composed of an optical output control through iris and filters with several wavelength bands. It also makes the inducement of auto-fluorescence possible because it is designed to generate a wavelength band of 380-420nm, 430-480nm, 480-560nm. The transmission part of the light source was developed to enhance the efficiency of light transmission. To evaluate this light source device by KFDA#s technical reference, the characteristics of the light output and wavelength band were found.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.62 no.6
• /
• pp.731-736
• /
• 2013

Most of faults occurring in transmission lines are transient faults. For such faults, automatic reclosing is economic and effective method to improve the reliability and transient stability of power system. Many countries apply various reclosing schemes considering issues of their own systems such as transient stability, rate of success. Currently, different reclosing schemes are applied in Korean transmission systems according to a rated voltage. In this paper, we conduct an evaluation of reclosing schemes in Korean transmission systems considering transient stability. Computer simulations are performed by using ElectroMagnetic Transient Program (EMTP) and transmission system is modeled based on actual data of Korea.

• Proceedings of the KIEE Conference
• /
• 2004.11b
• /
• pp.36-38
• /
• 2004

In many countries, including Korea, in order to transmit the more electric power, the higher transmission line voltage is inevitable. So, a rapid reclosing scheme is important for UHV transmission lines to ensure requirements for high reliability of main lines. But, because of the high voltage and long span of UHV lines, the secondary arc current flows across the fault point even after the interruption of the fault current. i.e. A critical aspect of reclosing operation is the extinction of the secondary arc since it must extinguish before successful reclosure can occur. In Korea transmission lines, it is scheduled to energize 765kV single transmission line(79km) between Sin-Ansung S/S and Sin-Gapyeong S/S at June 2006. Therefore this paper analyzes characteristics of the secondary arc extinction on 765kV single transmission line using EMTP. Simulation results shows that the average value of the secondary arc is $30A_{rms}$ and the auto-extinction time of it is longer at closer point to Sin-Gapyeong S/S.

• The KSFM Journal of Fluid Machinery
• /
• v.13 no.6
• /
• pp.71-76
• /
• 2010

This study has investigated numerically and experimentally the flow characteristic of air-cooling fan for transmission oil cooler in the large-size diesel engine. Impellers of cooler were composed of eight normal-scale and eight small-scale blades in the zig-zag pattern. In order to increase the discharge pressure of cooling fan, turbo type of fan blade is proposed in the impeller for transmission oil cooler. The fluidic performance of cooling fan has been estimated numerically by using the commercial code and experimentally carried out with reference on AMCA Standard 210-99. As a result, it is confirmed that the numerical result for performance curve is in good agreement with experimental data.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.32 no.10A
• /
• pp.1050-1056
• /
• 2007

In order to set up a steel frame at every construction site, it is necessary to attach a shackle to a crane to move steel frame beams and columns(H beams). The shackle used for this purpose must be removed manually from a higher place, which causes the risk of safety accidents to increase, work efficiency to decrease, and construction costs to rise. In this study, micro-mini, super lightweight, lower power consumptive, and cheaper auto-shackle with two-way RF communication, which can be used practically at construction site is designed and developed. The developed auto-shackle is able to have excellent remote monitoring and controlling functions, by adopting new operating principles and structures different from the existing one. The results of the study reveal that the auto-shackle can be applied for the purpose of remote controlling of various construction equipments and speed up the advancement of construction equipments.

• Journal of Korean Ophthalmic Optics Society
• /
• v.16 no.2
• /
• pp.107-115
• /
• 2011

Purpose: To design and fabricate the distributed auto edging machine for the development. Methods: We got the necessary data needed in design by using CAD. Based on the these data, we fabricated the trial product for the development of the distributed auto edging machine. Results: The patternless mode could be operated by receiving the eyesize data from the auto lay-outer with the RS232C transmission system and the pattern mode could be operated by setting the pattern on the left side of the machine. The distributed auto edging machine were composed with combinations of many elements; head, auto arm, pattern clamp and grinding wheels. The head part controlled the grinding of ophthalmic lens by operating the vertical and horizontal motors. The wheels part was comprised of glass mode, plastic mode, V-bevel mode and polish mode. The slide in the auto arm was equipped on the below of the patten and the slide could hold up the pattern which was rotated by fixed shaft. The pattern clamp could move the head part to the up and down or right or left way by the manual operation of optometrists. Conclusions: We could succeed in making the trial product by applying it to the development of the distributed auto edging machine which could be used as the patternless mode and pattern mode, selectively. Therefore, it was confidently expected that this product was very helpful for the optometrists to dispense the ophthalmic lens because of its cost-efficiency and convenience.