• The Journal of the Korea institute of electronic communication sciences
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• v.15 no.5
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• pp.813-818
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• 2020

This study is a study on the characteristics and analysis of the reflected signals about the target in the VHF band. In advance, the RCS(Radar Cross Section) characteristics of the target were analyzed by using the CST electromagnetic analysis tool, and the target was detected by using the Bi-Static method, and the change in the signal-to-noise ratio was tested. The test results show similar results with no significant fluctuations in the signal-to-noise ratio characteristics for the detection of signals reflected on the target, such as the results for RCS analysis according to the pre-incidence angle. In the future, this study will be used for RCS analysis of the targets and target detection of Radar in VHF/UHF band with relatively large wavelength compared to the X band.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.647-650
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• 2006

Low temperature polycrystalline silicon (LTPS) technology using a high power laser have been widely applied to thin film transistors (TFTs) for liquid crystal, organic light emitting diode (OLED) display, driver circuit for system on glass (SOG) and static random access memory (SRAM). Recently, the semiconductor industry is continuing its quest to create even more powerful CPU and memory chips. This requires increasing of individual device speed through the continual reduction of the minimum size of device features and increasing of device density on the chip. Moreover, the flat panel display industry also need to be brighter, with richer more vivid color, wider viewing angle, have faster video capability and be more durable at lower cost. Kornic Systems Co., Ltd. developed the $KORONA^{TM}$ LTP/GLTP series - an innovative production tool for fabricating flat panel displays and semiconductor devices - to meet these growing market demands and advance the volume production capabilities of flat panel displays and semiconductor industry. The $KORONA^{TM}\;LTP/GLTP$ series using DPSS laser and XeCl excimer laser is designed for the new generation of the wafer & FPD glass annealing processing equipment combining advanced low temperature poly-silicon (LTPS) crystallization technology and object-oriented software architecture with a semistandard graphical user interface (GUI). These leading edge systems show the superior annealing ability to the conventional other method. The $KORONA^{TM}\;LTP/GLTP$ series provides technical and economical benefits of advanced annealing solution to semiconductor and FPD production performance with an exceptional level of productivity. High throughput, low cost of ownership and optimized system efficiency brings the highest yield and lowest cost per wafer/glass on the annealing market.

• The Transactions of the Korean Institute of Power Electronics
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• v.6 no.2
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• pp.202-208
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• 2001

A Switched Reluctance Motor(SRM) has double salient poles structure and the phase windings are wound in stator. SRM hase more simple structure that of other motor, thus manufacture cost is low, mechanically strong, reliable to a poor environment such as high temperature, and maintenance cost is low because of brushless. SRM needs position detector to get rotator position information for phase excitation and tachometer or encoder for constant speed operation. But, this paper doesn\`s use an encoder of high cost for velocity measurement of rotator. Instead of it, the algorithm for position detection and velocity estimation from simple slotted disk has been proposed and developed. To implement variable speed digital control system with velocity estimation algorithm, the TMS320F240-20MIPS fixed point arithmetic processor of TI corporation is used. The experimental results of the developing system are enable to control speed with wide range, not only single pulse, hard chopping mode and soft chopping, ut also variable speed control, and advance angle control.

• Tunnel and Underground Space
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• v.25 no.2
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• pp.210-219
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• 2015

This paper describes a new quantitative process for evaluating the roughness of discontinuity, which is suggested as a qualitative criteria in RMR or Q-system. For this purpose, the Delphi method which is one of the surveying methods was introduced. The selected panels were asked to evaluate the roughness of discontinuities on the Web which was hosted by authors in advance. A total of 3 surveys were performed using JRCs suggested by Barton and Choubey as well as Ai generated by the Monte Carlo simulations. After each survey, the results were provided to all panels for comparing their decisions to others. As surveys proceeded, better consensus and convergence were achieved. With a good agreement of panels on roughness classification, the quantitative criteria for roughness of discontinuity in RMR and Q-system was established in this study.

• Journal of Biosystems Engineering
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• v.42 no.4
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• pp.283-292
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• 2017

Purpose: Japanese Apricot, a type of plum, has various medicinal and economical applications. Plums are quite popular worldwide, but their deseeding remains a serious impediment to their processing. Therefore, a plum (Japanese Apricot) seed remover (PSR) was developed that can use various types of cutters according to the purpose of the plum processing, and its performance was evaluated. Methods: The proposed PSR, which allows multipurpose cutters, namely, zero-, two-, and four-blade cutters, to be installed, was first designed and manufactured. To identify appropriate parameters related to the cutting pressure, plums were harvested from three regions during three harvesting periods, and their geometrical and mechanical properties were measured. After application of the parameters related to the cutting pressure, a performance test was carried out on both fresh and frozen plums by identifying the ratios of the flesh recovery, seed recovery, seed breakage, deseeding efficiency, and machine efficiency. Results: The results show that, using the proper calculation of the processing parameters, 100% deseeding efficiency was facilitated regardless of the type of cutter used. However, in the case of a four-blade cutter, there are significant differences in the flesh recovery ratio according to the plum setting angle. Between the fresh and frozen plums, all cutters showed a significantly better flesh recovery ratio for the case of fresh plums. Conclusions: This machine will advance the plum processing technology, and eventually help the plum industry flourish.

• The Journal of Engineering Geology
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• v.26 no.2
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• pp.187-196
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• 2016

We conducted three-dimensional finite element analysis to predict the presence of upcoming fault zones during tunneling. The analysis considered longitudinal displacements measured at tunnel face, and used 28 numerical models with various fault attitudes. The x-MR (moving range) control chart was used to analyze quantitatively the effects of faults distributed ahead of the tunnel face, given the occurrence of a longitudinal displacement. The numerical models with fault were classified as fault gouge, fault breccia, and fault damage zones. The width of fault cores was set to 1 m (fault gouge 0.5 m and fault breccia 0.5 m) and the width of fault damage zones was set to 2 m. The results, suggest that fault centers could be predicted at 2~26 m ahead of the tunnel face and that faults could be predicted earliest in the 45° dip model. In addition, faults could be predicted earliest when the angle between the direction of tunnel advance and the strike of the fault was smallest.

• Journal of the Korean Geotechnical Society
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• v.30 no.11
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• pp.5-15
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• 2014

It is very important to design and construct slopes safely because damage cases are increasing due to slope failure. Recently, Limit Equilibrium Method (LEM) based programs are commonly used for slope designs. Though LEM can give factors of safety through simple calculation, it has a disadvantage that the sliding surface should be assumed in advance. On the other hand, the use of Finite Difference Method (FDM) is increasing since the factor of safety can be easily estimated by using shear strength reduction technique. Therefore the purpose of this study is to present a reasonable slope design methodology by comparing the two commonly used analysis approaches; LEM and FDM. To this end, the reinforcement effects of the two methods were compared in terms of the support pattern of soil nailing reinforced in the section where plane failure is anticipated. As a result, the reinforcement effects by nail angle and nail spacing turned out to be equal. Also it was found that the factor of safety increased in LEM, but not changed in FDM when the nail length increased.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.30 no.6
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• pp.237-243
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• 2020

In this study, a silane-based coating was applied to improve corrosion resistance and thermal efficiency performance of a brazed plate heat exchanger (BPHE) composed of stainless plate and copper (Cu) brazing. Although the selected coating material was applied to the BPHE by evaluating the corrosion and contact angle according to the coating material, the result of the heat transfer performance evaluation showed that the thermal efficiency was lower than that of the uncoated BPHE. It was analyzed that the adhesion of the coating agent to the flow path inside the BPHE and the residual coating agent on the surface acted as heat resistance, preventing heat transfer. This is due to the structural characteristics of the BPHE in which a fine flow path exists inside, and it is believed that manufacturing after coating the surface of the flow path in advance in the manufacturing process of the BPHE can improve heat transfer performance.

• Journal of Drive and Control
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• v.19 no.4
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• pp.19-28
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• 2022

This paper introduces an automatic steering system for straight traveling capable of being mounted on drivable agricultural machinery which user can handle it such as a tractor, a transplant, etc. The modular automatic steering device proposed in the paper is composed of RTK GNSS, IMU, HMI, hydraulic valve, and wheel sensor. The path generation method of the automatic steering system is obtained from two location information(latitude and longitude on each point) measured by GNSS in advance. From HMI, a straight path(AB line) can be created by connecting latitude and longitude on each point and the device makes the machine able to follow the path. During traveling along the reference path, it acquires the real time position data every sample time(0.1s), compares the reference with them and calculates the lateral deviation. The values of deviation are used to control the steering angle of the machine using hydraulic valve mounted on the axle of front wheel. In this paper, Pure Pursuit algorithm is applied used in autonomous vehicles frequently. For the analysis of traveling characteristics, field tests were executed about these conditions: velocity of 2, 3, 4km/h which is applied to general agricultural work and ground surface of solid(asphalt) and weak condition(soil) such as farmland. In the case of weak ground state, two experiments were executed about no-load(without work) and load(with work such as plowing). The maximum average deviations were presented 2.44cm, 7.32cm, and 11.34cm during traveling on three ground conditions : asphalt, soil without load and with load(plowing).

• Journal of the Society of Naval Architects of Korea
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• v.59 no.5
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• pp.252-261
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• 2022

The present study concerns assessing the operability of a surface combatant, based on the Percent-Time-Operable (PTO). For validation of the seakeeping analysis in the regular waves, the model test is first conducted in a towing tank. The seakeeping analysis results in the regular waves are expanded to the irregular waves, considering the wave spectra around the Korean peninsula and in North Pacific. The seakeeping criteria of the surface combatant in transit, combat, replenishment operation, and survival condition are defined by the literature review. An annual operation scenario of the surface combatant in two operation areas, i.e., advance speed and wave direction, are combined with the seakeeping analysis results to assess PTO. The main constraints of operability of the surface combatant are identified as the pitch angle and vertical velocity at the helicopter deck.