• The Journal of Korean Institute of Communications and Information Sciences
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• v.15 no.2
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• pp.88-97
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• 1990

In this paper, DPA bus is proposed for implementation of MC 68000 based tightly-coupled multiprocessor system. The DPMC and arbiter are designed that the local memory of each PE can accept memory request both from a local processor and from the system bus. The performance of the proposed system bus is evaluated by Stochastic Petri Net(SPN) system modeling. The processing power, the efficiency, and the utilization of system bus are simulated for various load factors.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.4B
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• pp.613-623
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• 2000

Digital TV tuner for 8-VSB modulation was developed with satisfying the requirements of ATSC. The double frequency conversion and the active tracking filter in the front-end were used to reduce interference of the adjacent channels and multi-channels, which suppress If beat and image band. However, it was impossible to get frequency mapping between tracking filter and first VCO(Voltage Controlled Oscillator) in the double conversion digital TV tuner differing from conventional NTSC tuner. This paper, therefore, suggests the available structure and a new method for automatic frequency selection by obtaining the mapping of frequency characteristic over tracking voltage and the combined hardware which compose of Micro-controller, EEPROM, D/A(Digital-to-Analog Converter), OP amp and switch driver to solve above problems.

• Journal of Biosystems Engineering
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• v.25 no.5
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• pp.351-358
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• 2000

This study was conducted to develop a speed control system of a DC motor which drove a barley seeder mounted on a combine harvester. Barley seeder mounted on a combine has been known to reduce labor and cost of barley cultivation. However, development of the seeder has been unsuccessful because the combine, a dedicated rice and barley harvester has not enough space and proper power take-off for barley seeder. To develop a barley seeder, small powered motor speed controller was required. A proximity sensor for detecting working speed of the combine and a programmable one board microprocessor was used to develope a control system. Motor parameters and motor constant, relationship between seeding rate, motor speed, groove volumes of a tested roller, torque were measured. The proximity sensor sent a frequency signal to the microprocessor. In laboratory experiments, the excitation voltage of the motor was shown not to be proportional to the size of pulse width (duty ratio). A table transforming frequency signal, that represented for working speed to proper pulse width was developed from seeding rate experiments. However, seeding rate at low frequency signal was not proportional to the working speed. Seeding rate control proportional to the frequency signal was achieved by shifting of the frequency signal.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.4
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• pp.2385-2390
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• 2015

In the beginning run, urban railway had been required as transportation. But now days urban railway have stayed in the platform for long time, the platform is faced the problem that is improvement of environment as one of the living space. Thus, sliding automatic door on the basis of screen door have used in huge distribution market, hospital, restaurant and public office because it is comfortable that customer's convenience and entrance are controled. So screen door not only requires customer's convenience and safe, clean area and energy conservation but demands optimal design technology development of screen door system that is confirmed by element parts of design and confidence. In this paper, For secure confidence of screen door, after as modeling roller and frame's system, confirming the result for qualification of driving stiffness. And then it suggests that it is possible to increase performance and declines fraction defective of element's part.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.42 no.5
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• pp.497-502
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• 1997

A seed pelleting technique was developed for easy handling of small sesame seeds (Chinbaeckkae) and for direct seeding in field. The mixture of pelleting material, binder(sodium alginate) and seeds were dropped in 100mM CaCl$_2$ solution. Charcoal was appeared as a best material among all to make pellets with the characters of hardness, breakdown, destruction rate and germination percentage. Zeolite formed the hardest pellet seeds among the materials and 1~3 seeds contained in a pellet on the treatment of 87g of sesame seeds mixed in 1$\ell$ CaCl$_2$ solution was estimated optimum rate of seed mixure with few appearance of seedless pellet. The moisture absorption rate was greater in the order of peat＋charcoal > peat > charcoal > zeolite. Germination percentage of pelleted seeds with charcoal was the best and similar to that of common non-treated seeds. Germination percentage of pelleted seeds by sowing depth of exposing a quarter of pellet seeds on the surface of vermiculite germination test box and were 92％ in charcoal treatment and was the best among all released materials.

• Journal of the Microelectronics and Packaging Society
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• v.28 no.3
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• pp.33-38
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• 2021

Recently, rollable and foldable displays are attracting great attention in the flexible display market due to their excellent form factor. To predict and prevent the mechanical failure of the display panels, it is essential to accurately understand the mechanical properties of brittle SiN_x thin films, which have been used as an insulating film in flexible displays. In this study, tensile properties of the ~130 nm- and ~320 nm-thick SiN_x thin films were successfully measured by coating a ~190 nm-thick organic nano-support-layer (PMMA, PS, P3HT) on the fragile SiN_x thin films and stretching the films as a bilayer state. Young's modulus values of the ~130 nm and ~320 nm SiN_x thin films fabricated through the controlled chamber pressure and deposition power (A: 1250 mTorr, 450 W/B: 1000 mTorr, 600 W/C: 750 mTorr, 700 W) were calculated as A: 76.6±3.5, B: 85.8±4.6, C: 117.4±6.5 GPa and A: 100.1±12.9, B: 117.9±9.7, C: 159.6 GPa, respectively. As a result, Young's modulus of ~320 nm SiN_x thin films fabricated through the same deposition condition increased compared to the ~130 nm SiN_x thin films. The tensile testing method using the organic nano-support-layer was effective in the precise measurement of the mechanical properties of the brittle thin films. The method developed in this study can contribute to the robust design of the rollable and foldable displays by enabling quantitative measurement of mechanical properties of fragile thin films for flexible displays.

• The Journal of the Convergence on Culture Technology
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• v.9 no.6
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• pp.41-47
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• 2023

This study was conducted to determine the effect of an exercise program applied to prevent musculoskeletal changes that occur due to aging on pain, muscle strength, balance ability, and falling efficacy in elderly women. An exercise program including quadriceps setting exercise, bridge exercise, resistance band exercise, and foam roller exercise was applied to elderly women aged 65 years or older once a week for 8 weeks. A visual analog scale was used to evaluate pain, muscle strength was evaluated using a digital muscle strength meter, balance ability was measured using the Berg balance scale, and fear of falling was evaluated using the fall efficacy scale. As a result of the study, compared to before the experiment, pain in the lower back and knee area was significantly reduced, the strength of the quadriceps femoris and gluteus maximus was significantly increased, and balance ability and falling efficacy were significantly improved. In conclusion, application of a program that includes various exercise methods has a positive effect on the physical activity of elderly women by strengthening the musculoskeletal system. Additionally, in order to prevent physical changes due to aging, an exercise program that includes various exercise methods that can strengthen the musculoskeletal system should be applied.

• Journal of Bio-Environment Control
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• v.20 no.2
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• pp.93-100
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• 2011

Maintenance of adequate soil water potential during the period of crop growth is necessary to support optimum plant growth and yields. A better understanding of soil water movement within and below the rooting zone can facilitate optimal irrigation scheduling aimed at minimizing the adverse effects of water stress on crop growth and development and the leaching of water below the root zone which can have adverse environmental effects. The objective of this study was to evaluate the feasibility of using a portable irrigation controller with an Watermark sensor for the cultivation of drip-irrigated vegetable crops in a greenhouse. The control capability of the irrigation controller for a soil water potential of -20 kPa was evaluated under summer conditions by cultivating 45-day-old tomato plants grown in three differently textured soils (sandy loam, loam, and loamy sands). Water contents through each soil profile were continuously monitored using three Sentek probes, each consisting of three capacitance sensors at 10, 20, and 30 cm depths. Even though a repeatable cycling of soil water potential occurred for the potential treatment, the lower limit of the Watermark (about 0 kPa) obtained in this study presented a limitation of using the Watermark sensor for optimal irrigation of tomato plants where -20 kPa was used as a point for triggering irrigations. This problem might be related to the slow response time and inadequate soil-sensor interface of the Watermark sensor as compared to a porous and ceramic cup-based tensiometer with a sensitive pressure transducer. In addition, the irrigation time of 50 to 60 min at each of the irrigation operation gave a rapid drop of the potential to zero, resulting in over irrigation of tomatoes. There were differences in water content among the three different soil types under the variable rate irrigation, showing a range of water contents of 16 to 24%, 17 to 28%, and 24 to 32% for loamy sand, sandy loam, and loam soils, respectively. The greatest rate increase in water content was observed in the top of 10 cm depth of sandy loam soil within almost 60 min from the start of irrigation.