• Journal of the Korean Institute of Telematics and Electronics A
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• v.32A no.8
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• pp.153-165
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• 1995

The design procedure of a GaAs/AlGaAs semiconductor matrix optical switch is presented for a simplified tree architecture in the viewpoint of optical loss. A low loss, 0.537 dB/cm, pin type substrate is designed by considering the loss due to imputity doping at 1.3 $\mu$m wavelength. The operating voltage and the device length of a reversed ${\Delta}{\beta}$ electro-optic directional coupler(EODC) swith which is a cross-point device of the 4${\times}$4 matrix optical switch and the bending loss of rib waveguide are caculated as functions of waveguide parameters and bending parameters. There is an optimum bending radius for some waveguide parameters. It is recommened that higher optical confinement conditions such as wide waveguide width and higher rib-height should be chosen for structural parameters of a low loss and a process insensitive 4${\times}$4 matris optical switch. A 4${\times}$4 optical matrix switch which has a 3 dB loss and a 12 volt operating voltage is designed.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.9
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• pp.1633-1640
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• 2016

In this paper, we propose a open-ended rectangular microstirp patch antenna with fork-shaped feeding structure. This antenna extends the effective bandwidth by transforming single or multi resonant frequency and is designed planar monopole structure with microstrip line to satisfy the WLAN bands (2.4 - 2.484, 5.15 - 5.35, 5.25-5.825 GHz). The substrate is printed in 0.8 mm thickness on an FR-4 board. A commercial 3D simulation tool was used to analyze surface current and electromagnetic field distribution in order to analyze the operation mode and reconfiguration principle of antenna. According to the lengths of individual patches, simulated reflection loss was compared to obtain optimized values. When it was designed with the optimized values, it satisfied WLAN bands (2.380 - 2.710, 4.900 - 5.950 GHz), if the switch is off, and 2.4 WLAN band (2.380 - 2.710 GHz). From the fabricated and measured results, measured results of return loss, gain and radiation patterns characteristics displayed for operating bands.

• Journal of Biosystems Engineering
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• v.27 no.3
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• pp.203-210
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• 2002

In this study, the leveling control system for a tractor has been developed. The experimental model showed that the implementation of the proposed hydraulic control system fur the prototype design of a slope land tractor was feasible. The front axle was designed as a center pin type and the rear axle was designed as a trailing arm type. The leveling control of the body on the slope land was accomplished by controlling the height of the right and left trailing arms using the electronic controlled hydraulic cylinder. The maximum leveling control angles were ${\pm}$15$^{\circ}$ for roll angle and 7$^{\circ}$far pitch angle. The front and rear wheel drives were transmitted by gears from the main shaft to the final drive. The adaptability of the hydraulic control system was tested and investigated by analyzing the system response in time and frequency domain. The hydraulic control system on a step input showed a linearly increasing trend without any overshoot state. The hydraulic control system on a frequency input showed a little phase differences and gain drops within the range of 0.3Hz.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.5
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• pp.2061-2066
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• 2011

A cycloid speed reducer is one of the rotational speed regulation devices of the machinery. A cycloid speed reducer has an advantage of transmitting high torque, but is known to be unsuitable for high speed rotation. However, it is almost impossible in an analytical method to find a use limit speed when installing such a speed reducer in a 200ton loading transporter. In this research the cycloid reducer was simulated to get its performance depending on friction energy loss in time domain by using by LS-DYNA. The maximum torque of the cycloid speed reducer is 3.5ton-m, so the comparison of analysis results between a case of 60rpm rotation and a case of 162rpm rotation with such a torque showed the following results. In the case of 60rpm rotation, the maximum stress appearing in the RV gear and the pin gear was 463MPa and 507MPa. Lost power due to friction was 50kW; In the case of 162rpm rotation, the maximum stress appearing in the RV gear and the pin gear was 550MPa and 538MPa. Lost power due to friction was 175kW, which was shown to be almost impossible to use.

• Nuclear Engineering and Technology
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• v.55 no.10
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• pp.3732-3753
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• 2023

The Real-time Analysis for Particle-transport and In-situ Detection (RAPID) Code System, developed based on the Multi-stage Response-function Transport (MRT) methodology, enables real-time simulation of nuclear systems such as reactor cores, spent nuclear fuel pools and casks, and sub-critical facilities. This paper presents the application of a novel fission matrix-based burnup methodology to the well-characterized JSI TRIGA Mark II research reactor. This methodology allows for calculation of nuclear fuel depletion by combination and interpolation of RAPID's burnup dependent fission matrix (FM) coefficients to take into account core changes due to burnup. The methodology is compared to experimentally validated Serpent-2 Monte Carlo depletion calculations. The results show that the burnup methodology for RAPID (bRAPID) implemented into RAPID is capable of accurately calculating the k_eff burnup changes of the reactor core as the average discrepancies throughout the whole burnup interval are 37 pcm. Furthermore, capability of accurately describing 3D fission source distribution changes with burnup is demonstrated by having less than 1% relative discrepancies compared to Serpent-2. Good agreement is observed for axially and pin-wise dependent fuel burnup and nuclear fuel nuclide composition as a function of burnup. It is demonstrated that bRAPID accurately describes burnup in areas with high gradients of neutron flux (e.g. vicinity of control rods). Observed discrepancies for some isotopes are explained by analyzing the neutron spectrum. This paper presents a powerful depletion calculation tool that is capable of characterization of spent nuclear fuel on the fly while the reactor is in operation.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.14 no.6
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• pp.7-13
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• 2015

The production processes were reviewed through the injection analysis of the shift lever as a core component of an auto lever installed in the automatic transmission of cars. The injection analysis was carried out for the shift lever and rod among the components in a shift lever module. The shift lever and rod are designed for injection molding with the insertion of a tube, a pin cable plate, and a steel rod for securing the strength of the product. The charging time, failure of injection molding, weld line, air trap, and deformation were reviewed according to this insert. Analyses on various gate positions were carried out for reviewing the cultivation and deformation of fiber around major components, such as the generation section of manipulation feeling and assembly section, so that optimal gate conditions might be reviewed and reflected in the mold design. Finally, we plan to compare the analysis results with the production of trial products.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.1664-1667
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• 2005

The main function of Ball-Stop part is to operate power shift for vehicle with more than 5 ton when a driver changes gear using suitable force. This paper presents the implementation of a DFSS(Design For Six Sigma) for robust design of Ball-Stop part of power shift. The factors influencing Ball-Stop part performance is derived to find control factor. Based on this factor, contact force between head and detent pin analysis is performed to get optimal factor is analyzed and compared with contact force test result to verify reliability of design. This makes clear the reason why the proposed one is necessary and the role of DFSS.

• International Journal of Fluid Machinery and Systems
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• v.7 no.2
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• pp.60-67
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• 2014

In order to clarify the effect of inlet bellmouth size of semi-opened type axial fan on its performance and flow fields around rotor, fan test and flow field measurements using hotwire anemometer were carried out for 6 kinds of bellmouth size. As results of fan test, the shaft power curve hardly changed, even if the bellmouth size changed. On the other hand, the pressure-rise near best efficiency point became small with the bellmouth size decreasing. Therefore, the value of maximum efficiency became small as the bellmouth size decreased. As results of flow field measurements at fan inlet, the main flow region with large meridional velocity existed near blade tip when the bellmouth size was large. As bellmouth size became smaller, the meridional velocity at fan inlet became smaller and the one at outside of blade tip became larger. As results of flow field measurements at fan outlet, the main flow region existed near rotor hub side.

• Journal of the Korea Management Engineers Society
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• v.23 no.4
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• pp.33-48
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• 2018

Despite that QR codes are spreading worldwide in Pin Tech, logistics distribution, etc., South Korea is staying at the level of using QR codes in limited areas such as website connection and marketing communication. The purpose of this study is to propose measures for more effective use of QR codes by examining the effects of personal innovativeness on user's behavioral intentions by applying personal innovativeness to QR codes. To this end, this study was intended to examine the relationships between performance expectancy (PE), effort expectancy (EE), social expectancy (SE), and personal innovativeness, which are variables used in the Unified Theory of Acceptance and Use of Technology (UTAUT) model among innovative technology acceptance models, and behavioral intentions. For this study, a questionnaire survey was conducted with students in collages in the metropolitan area in May 2018 and the results were statistically verified using IBM SPSS 21. The results showed that PE, EE, and SE had significant positive(+) effects on personal innovativeness and behavioral intentions of QR code users. The mediating effects of personal innovativeness were tested and the results indicated that personal innovativeness partially mediates between PE and behavioral intentions and between EE and behavioral intentions but not between SE and behavioral intentions. The fact that since QR codes are expressed as a component to users through other media rather than its internal factors, the personal innovativeness of QR code users plays an important role in increasing the use of QR codes could be identified through this study.

• The Research Journal of the Costume Culture
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• v.29 no.6
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• pp.763-778
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• 2021

The study aims to analyze the mixed characteristics of knit fashion design as demonstrated in Sacai's collection, which promotes hybrid and mesh-up fusion and proposes various knit design ideas. Standards for categorizing mixed phenomena of Sacai's knit design were established through a review of literature and data analysis. The study's data collection period was from 2012 to 2021, and a total of 174 items were analyzed. The following are the results. First is the fusion of traditional knit and contemporary styles expressed through de-constructive design; traditional knit styles are combined with contemporary styles through color, material, and knitting structure mixtures, such as mixing Northern European Aran, Fair Isle, Nordic, and Ropy knit. Second, the Sakai knit design combines male and female styles by mixing materials and details. A deconstructed knit cardigan was matched with androcentric pin-striped shirts worn over layered shirring skirts embellished with chiffon and lace. Third, everyday street fashion style is blended with a formal, elegant fashion style. For example, the front view has a typical everyday appearance, whereas the back view contains florid and decorated details. The style is expressed as a 360-degrees appellation, with one thing in the front and another in the back. Sacai's distinctive expressional characteristics include a mixed and de-constructive style characterized by unexpected design.