• Korean Journal of Plant Resources
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• v.29 no.5
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• pp.579-587
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• 2016

The final goal of this research is to develop a miniaturized botanical biofilter using a wick-typed automatic humidifier for stabilizing soil moisture content (SMC) and purifying indoor air pollutants by the biofilter. This new biofilter equipped with wick-typed automatic humidifier was manufactured as more compacted design removing an absorption tower-typed humidifier compared with the previous big-sized biofilter made in 2015. This study was performed to compare changes of SMCs among floors depending on the number of wicks installed on the humidifier within the novel biofilter, and to compare changes of SMCs and plant growth parameters before and after planting Spathiphyllum wallisii ‘Mauna Loa’ on the biofilter. SMCs among floors depending on the number of wicks were similar, and all regression lines of SMCs showed almost horizontal lines because of long-term stability on SMCs. Comparing plant growth parameters of S. wallisii ‘Mauna Loa’ before planting and at 30 days after planting on the biofilter, all growth parameters were not statistically significant. Thus, SMCs of the biofilter were more stabilized using this humidifying apparatus regardless of the number of wicks than the previous biofilter using absorption tower-typed humidifying apparatus.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.14 no.5
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• pp.249-254
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• 2014

In this paper, minimizing of a parabolic edge planar monopole antenna by scaling method is presented. With the aid of a matching step and discontinuous CPW, the antenna easily adjusts the impedance matching. We used an FR4 dielectric substrate with a dielectric constant of 4.4. The dimensions of the antenna are $26mm{\times}31mm{\times}1.6mm$. A return loss value of more than 10dB was found in the 2.37GHz to 10.52GHz (8.15GHz) range of the antenna fed by the discontinuous CPW. The radiation pattern is about the same as that of the dipole antenna at all frequencies. Configuration elements of the antenna except feed part were reduced into the same rate. So, the size of the antenna was decreased and a broadband property was maintained. Therefore, the self-complementary characteristic of the antenna was confirmed. While satisfying the UWB band, having the smallest size in the antenna miniaturized by scaling;when scale was 0.6. The dimensions of the antenna are $15.6mm{\times}18.6mm{\times}1.6mm$. The return loss was more than 10 dB of the measured result in the range of 3.07GHz to 12.59GHz (9.52GHz).

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.8
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• pp.844-853
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• 2008

This paper describes the design of a FEM(Front End Module) having power detection function for mobile handset application. The designed FEM consists of a MMIC(Monolithic Microwave Integrated Circuits) power amplifier chip, SAW Tx filter and duplexer, diode power detector and stripline matching circuit. An LTCC(Low Temperature Co-fired Ceramics) technology is adopted for miniaturized FEM. The frequency band is $824{\sim}869$ MHz which is the uplink Tx band of the CDMA mobile system. The size of designed FEM is $7.0{\times}5.5{\times}1.5\;mm^3$, which is an ultra-small size even though the power detector circuit is included. All sub-components of FEM have been developed and measured in advance before being integrated into FEM. The measured output power and gain are 27 dBm and 27 dB, respectively. In addition, the measured ACPR characteristics are 46.59 dBc and 55.5 dBc at 885 kHz and 1.98 MHz offset, respectively.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.8
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• pp.745-753
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• 2011

In this paper, the planar monopole antenna for multi-band service is proposed. The proposed antenna, which is a rectangular patch antenna with a U-shaped slit based on a monopole antenna for wide bandwidth characteristic, is designed and analyzed. The antenna size has been miniaturized by using the U-shaped slit. The frequency characteristics are modified and optimized by varying specific parameters. To obtain desired frequency bands, the U-shaped slit and patch lines have been applied. Whole antenna dimensions including the ground plane are $35{\times}50{\times}1\;mm^3$, and the antenna part size is $35{\times}27\;mm^2$. It is fabricated on the FR-4 substrate(${\epsilon}_r=4.4$) using a microstrip line of $50{\Omega}$ for impedance matching. For the measured results, the impedance bandwidth below a VSWR of 2 is 790~916 MHz, 1.74~2.14 GHz, and 2.36~3.13 GHz. The fabricated antenna is satisfied with the aimed impedance bandwidth in GSM/DCS/US-PCS/UMTS/Bluetooth/S-DMB applications.

• Journal of Advanced Navigation Technology
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• v.22 no.5
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• pp.442-448
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• 2018

In this paper, a microstrip antenna for LTE / LTE-A is designed and fabricated for a broadband mobile communication system. The proposed antenna is designed to have the characteristics of using FR-4 (er = 4.3), size of $40mm{\times}50mm$, and LTE / LTE-A frequency bands of 2.3 GHz and 2.5 GHz. 2014, and the simulation result shows that the gain is 2.391 dBi at 2.3 GHz and 2.566 dBi at 2.5 GHz. The S-parameter also showed a result of less than -10 dB (WSWR 2: 1) in the desired frequency band. The broadband mobile communication antenna has been miniaturized, high performance, and light weight, and an excellent and low cost system is continuously being developed, and a broadband mobile communication system is used by many people. Since LTE / LTE-A technology has been proposed according to the development of system and demand, it is expected that many users will design and manufacture antennas satisfying the above conditions and apply the applied technology.

• Journal of Navigation and Port Research
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• v.31 no.5 s.121
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• pp.415-420
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• 2007

In this paper, we have designed and fabricated a new type of bandpass-filter that used rectangular ring and interdigital capacitive feeding-structure. The filter is applied the modified rectangular ring and interdigital capacitive feeding-structure in patch, which reduce rho size of filter and IEEE 802. 11 correspond to wireless LAN domain(2.45GHz and 5.2GHz) for operating. As a result, the design and fabrication process of the filter become simple and the size of it is reduced more than 60% compared with RF filter are available conventional PEMBF(Parallel Edge-coupled Microstrip Bandpass Filter) of accounted circuit by minimum stage, measurement result of fabricated filter, center frequence is down 2.408GHz and 5.075GHz. input return loss is -39.169dB at 2.408GHz, -40.922dB at 5.075GHz. insertion loss is -0.437dB at 2.408GHz, -1.669dB at 5.075GHz.

• Korean Journal of Weed Science
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• v.31 no.3
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• pp.229-239
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• 2011

This study was carried out to establish an improved bioassay system on the side of practicality, pre-emergence bioassay which is more effective in developing soil application natural herbicides. A miniaturized method which have a 50 cm2 of soil surface area and was efficient by 7 times compared to the existing soil application assay ($350cm^2$ of soil surface area) was established, in which four weed species (Echinochloa crus-galli, Digitaria sanguinalis, Aeschynomene indica, and Abutilon theophrasti) were planted and grown in greenhouse. This would be applicable when the amount of screening compound is much more than 50 mg. The initial application rate was desirable at $10,000{\mu}g\;mL^{-1}$. On the other hand, the 6 well plate assay which has 4 weed species in each well containing upland soil and could be conducted in growth chamber, was established. This assay was resulted in minimizing in level of 1/14 test volume and 1/14 amounts of test compound to the conventional method that has been used for screening of synthetic compounds in KRICT, and applicable for the small amount of test compound (less than 10 mg). Therefore, the improved bioassays established in this study would be helpful for a rapid and efficient development of soil application natural herbicides.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.36 no.10
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• pp.1189-1193
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• 2012

The Miniaturized Fingerprint Imager (MFI) is a slim optical mouse that can be used as an input device for application to wireless portable personnel communication devices such as smartphones. In this study, we have fabricated key optical components of an MFI, including the illumination optical components and imaging lens. An LED beam-shaping lens consisting of an aspheric lens and a Fresnel facet was successfully machined using a diamond turning machine (DTM). A customized V-shaped groove for beam path banding was fabricated by the bulk micromachining of silicon that was coated with aluminum using the shadow effect in thermal evaporation. The imaging lens and arrayed multilevel Fresnel lenses were fabricated by electron beam lithography and FAB etching, respectively. The proposed optical components are extremely compact and have high optical efficiency; therefore, they are applicable to ultraslim optical systems.

• Design & Manufacturing
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• v.12 no.1
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• pp.52-57
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• 2018

With the recent strengthening of environmental regulations and the need for cost reduction, excavators, a type of construction equipment, are being miniaturized while components are being developed in consideration of stability. In the case of excavator press parts, mainly high-strength steel sheets are being used to enhance stability and reduce weight. However, in the case of high-strength materials, there is a need to research product forming methods to reduce Springback in defects arising in parts assembly due to Springback that result from the internal residual stress that occurs in press forming being released after product forming. Accordingly, regarding the tank cover, an excavator press-forming part, this study selected a method to reduce distortion through analysis of the Springback occurrence rate and Springback causes through a forming analysis. A forming analysis was conducted for the Springback of the tank cover. Deformations of 13.714 mm in the upper part and 6.244 mm in the inner part of the product occurred, while wrinkles occurred on the sides of the product due to uneven thickness. A forming analysis was conducted for the major shapes of the product to investigate the causes of Springback. Distortion deformation due to the bead in the center of the product was confirmed to be a large factor. A Springback reduction method of correcting uneven thickness in the product sides, a Springback reduction method of removing the bead, and a correction method of restriking after the final forming were used in a forming analysis to determine the degree of Springback reduction. For the forming method to correct uneven thickness in the sides, deformation was reduced by 12% in the upper side compared to the existing model, but deformation in the inner side increased by 1%. For the restriking forming method, deformation decreased by 25% in the upper side and 13% in the inner side. For the bead removal method, deformation decreased by 28% in the upper side and 13% in the inner side, the largest Springback correction results. This indicates that the bead has a large affect on Springback.

• Journal of the Institute of Convergence Signal Processing
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• v.8 no.4
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• pp.237-243
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• 2007

In this paper, we propose the Real-time Dead-Pixel Detection and Compensation System for mobile camera and its hardware architecture. The CMOS image sensors as image input devices are becoming popular due to the demand for miniaturized, low-power and cost-effective imaging systems. However a conventional Dead-Pixel Detection Algorithm is disable to detect neighboring dead pixels and it degrades image quality by wrong detection and compensation. To detect dead pixels the proposed system is classifying dead pixels into Hot pixel and Cold pixel. Also, the proposed algorithm is processing line-detector and $5{\times}5$ window-detector consecutively. The line-detector and window-detector can search dead pixels by using one-dimensional(only horizontal) method in low frequency area and two-dimensional(vertical and diagonal) method in high frequency area, respectively. The experimental result shows that it can detect 99% of dead pixels. It was designed in Verilog hardware description language and total gate count is 23K using TSMC 0.25um ASIC library.