• ETRI Journal
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• v.46 no.3
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• pp.550-563
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• 2024

A novel inductance simulation circuit employing only two dual-output voltage-differencing buffered amplifiers (DO-VDBAs) and a single capacitance (grounded) is proposed in this paper. The reported configuration is a purely resistor-less realization that provides electronically controllable realized inductance through biasing quantities of DO-VDBAs and does not rely on any constraints related to matched values of parameters. This structure exhibits excellent behavior under the influence of tracking errors in DO-VDBAs and does not exhibit instability at high frequencies. The simple and compact metal-oxide semiconductor (MOS) implementation of the DO-VDBAs (eight MOS per DO-VDBA) and adoption of grounded capacitance make the proposed circuit suitable for on-chip realization from the perspective of chip area consumption. The function of the pure grounded inductance is validated through high pass/bandpass filtering applications. To test the proposed design, simulations were performed in the PSPICE environment. Experimental validation was also conducted using the integrated circuit CA3080 and operational amplifier LF-356.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.1066-1070
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• 2003

Recently technologies have created new principle and theory but the PID control system remains its popularity as the PID controller contains simple structure, including maintenance and parameter adjustment being so simple. Thus, this paper proposes auto tune PID by fuzzy logic controller based on FPGA which to achieve real time and small size circuit board. The digital PID controller design to consist of analog to digital converter which use chip TDA8763AM/3 (10 bit high-speed low power ADC), digital to analog converter which use two chip DAC08 (8 bit digital to analog converters) and fuzzy logic tune digital PID processor embedded on chip FPGA XC2S50-5tq-144. The digital PID processor was designed by fundamental PID equation which architectures including multiplier, adder, subtracter and some other logic gate. The fuzzy logic tune digital PID was designed by look up table (LUT) method which data storage into ROM refer from trial and error process. The digital PID processor verified behavior by the application program ModelSimXE. The result of simulation when input is units step and vary controller gain ($K_p$, $K_i$ and $K_d$) are similarity with theory of PID and maximum execution time is 150 ns/action at frequency are 30 MHz. The fuzzy logic tune digital PID controller based on FPGA was verified by control model of level control system which can control level into model are correctly and rapidly. Finally, this design use small size circuit board and very faster than computer and microcontroller.

• Journal of the Microelectronics and Packaging Society
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• v.29 no.2
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• pp.49-52
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• 2022

As the difficulty of flip chip products increase, interest in stable PKG material technology from the viewpoint of reliability is increasing. Currently, the representative of poor reliability that are mainly occurring in flip chip PKG are Sn bridge and Cu dendrite. Two type defects are caused by void generated by the flux residue around the bump. In order to essentially minimize the risk of this type of reliability failure, the linkage between the composition of Molded Under-fill (MUF) and flux, which is related material, was reviewed. In this study, the correlation between base resin and filler, which is the main component of MUF, and flux, was defined, and the material composition design was carried out by refer to lesson learn. With the current material composition, it was confirmed that moisture absorption reliability 85%/85%/24hrs pass result and void did not occur during destructive analysis, and developed MUF has shown flux immunity improving result in flip Chip PKG. We think this study can be used in yield enhancement of flip chip process and give insights to study in compatibility between MUF and flux.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.18 no.6
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• pp.227-237
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• 2015

From January 2013 to October 2015, weed invasion control techniques was tested in the test road of Jungbunaeryuk expressway so as to collect preliminary data for the management methods of the upper exterior banking of expressway shoulders. Then, monitoring was conducted and its results are as follows. Mat (sheet), solidifying agent, and mulching (wood chips) were applied for the test and their initial effects of preventing weed invasion were all excellent. It was found that the homogeneity of the wood chip mulching method needs to improve. In the mat method and the mulching method were found to have the most excellent economic feasibility and aesthetics, respectively. The covering degree was found to be the highest at 80% in the control site, followed by the wood chip site at 20% and the solidifying agent site and the non-woven fabric site at 5% each. As for species diversity, the control had the largest variety of species. Two years after the construction, many different species of plants invaded and were growing. Plants including weed didn't tend to invade the slopes applied with non-woven fabric. In addition, weed didn't invade the solidifying agent site and the aesthetics of the upper exterior banking of expressway shoulders was found to be excellent. The wood chip site was found to require consistent management for preventing weed invasion. The mat (sheet) site, the solidifying agent site, and the wood chip mulching site were found to have excellent weed prevention effects. As time passed, the mat (sheet) site and the solidifying agent site showed better weed prevention effects. However, they need consistent monitoring for further application.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.7 no.3
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• pp.86-95
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• 2004

This study was conducted to develop recycle revegetation methods for the restoration of the steep slopes by using fresh wood chip from construction sites. In general, the fresh wood chips can be used as soil media for the restoration works, because they can increase infiltration of rainfall and give enough porous to breathe and elongate for the root growth as well as economic value. The experiment was carried out to compare the effect of fresh wood chips from different mixing with soil, organic material and macromolecular compound which used for slope restoration works conducted by Hyunwoo green(Ltd.). The main results by monitoring for two years are summarized as follows; 1. The soil media made with low percentage of fresh wood chip covered quickly by herb plants. Especially, the soil mixture Type C (wood chip 20%) showed 80 percent ground coverage within two months after seeding. 2. The soil mixture type E (wood chip 40%) and type F (wood chip 50%) which contains more fresh wood chips than soil type C was under 30 percent ground coverage because wood plants are germinated well. If the restoration works aims at making forest, then the soil type E and F would be recommended than using soil type C. 3. Among the woody plants, Ailanthus alfissima, Pinus rigida, Pinus densiflora, and Albizzia julibrissin showed high percentage of germination rates and vigorous growth. In case of shrubs, Lespedeza cyrtobotria and Indigofera pseudo-tintoria scored high percentage of germination rates. 4. In native plants, Chrysanthemum indicum, Artemisia princeps, Lutos corniculatus and Imperata cylindrica showed high percentage of appearance. In case of introduced herbs, Coreopsis lanceolata, Coreopsis tinctoria and Oenothera oborata grew so vigorously. 5. The soil types which including fresh wood chips over 30-40 percentage showed the most diverse plant composition and the most effective germination rates and growth pattern with woody plants. 6. This works to develop recycle revegetation methods using fresh wood chips need more efforts for monitoring the exact effect of fresh wood chips as the soil media.

• Tribology and Lubricants
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• v.28 no.4
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• pp.173-177
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• 2012

We used contact resonance force microscopy (CRFM) technique to determine the quantitative elastic properties of multiple materials integrated on the sub micrometer scale. The CRFM approach measures the frequencies of an AFM cantilever's first two flexural resonances while in contact with a material. The plain strain modulus of an unknown or test material can be obtained by comparing the resonant spectrum of the test material to that of a reference material. In this study we examined the following bumping materials for flip chip by using copper electrode as a reference material: NiP, Solder (Sn-Au-Cu alloy) and under filled epoxy. Data were analyzed by conventional beam dynamics and contact dynamics. The results showed a good agreement (~15% difference) with corresponding values determined by nanoindentaion. These results provide insight into the use of CRFM methods to attain reliable and accurate measurements of elastic properties of materials on the nanoscale.

• Journal of Bio-Environment Control
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• v.22 no.3
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• pp.248-255
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• 2013

This study examined an automated irrigation technique by a frequency domain reflectometry (FDR) sensor for scheduling irrigation for tomato (Solanum lycopersicum L. 'Starbuck F1') cultivation aimed at avoiding effluent from an open hydroponic system with coir substrate containing different ratios of chip-to-dust (v/v) content. Specifically, the objectives were to undertake preliminary measurements of irrigation volumes, leachate volume, volumetric water content and electrical conductivity (EC) in the substrate, plant growth, fruit yield, and water use efficiency resulting from variation in chip content as an initial experiment. Commercial coir substrates containing different percentages of chips and dust (0 and 100%, 30 and 70%, 50 and 50%, or 70 and 30%), two-story coir substrates with different percentages of chips in the lower layer and dust in the upper layer (15 and 85%, 25 and 75%, or 35 and 65%), or rockwool slabs were used. The results showed that a negligible or no leachate was found for all treatments when plants were grown under a technique for scheduling non-drainage irrigation using a frequency domain reflectometry (FDR) sensor. Daily irrigation volume was affected by chip content in both commercial and two-story slabs. The highest plant growth, marketable fruit weight, and water-use efficiency were observed in the plants grown in the commercial coir slab containing 0% chips and 100% dust, indicating that the FDR sensor-auto-mated irrigation may be more useful for tomato cultivation in coir substrate containing 0% chips and 100% dust using water efficiently and minimizing or avoiding leachate and thus increasing yield and reducing pollution. Detailed experiment is necessary to closely focus on determining appropriate irrigation volume at each of irrigation as well as duration of each individual irrigation cycle depending on different physical properties of substrates using an automated irrigation system operated by the FDR sensor.

• Journal of Sensor Science and Technology
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• v.22 no.2
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• pp.144-149
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• 2013

In this research, we developed a biosensor to detect lung cancer-specific biomarker using Anodic Aluminum Oxide (AAO) chip based on interference and nano surface plasmon resonance (nanoSPR). The nano-porous AAO chip was fabricated $2{\mu}m$ of pore-depth by two-step anodizing method for surface uniformity. NanoSPR has sensitivity to the refractive index (RI) of the surrounding medium and also provides simple and label-free detection when specific antibodies are immobilized to the Au-deposited surface of nano-porous AAO chip. To detect the lung cancer-specific biomarker, antibodies were immobilized on the surface of the chip by Self Assembled Monolayer (SAM) method. Since then lung cancer-specific biomarker was applied atop the antibodies immobilized layer. The specific reaction of the antigen-antibody contributed to the change in the refractive index that cause shift of resonance spectrum in the interference pattern. The Limit of Detection (LOD) was 1 fg/ml by using our nano-porous AAO biosensor chip.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1998.03a
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• pp.5-10
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• 1998

Although the high speed machining technology (HSM) has been significantly studied in worldwide for past two decades, and has been widely applied in machining processes at many countries, it is not well known in domestic machining industries. The objective of this article, therefore, is to introduce the HSM to domestic industries so that they can apply the HSM on their products and results in improvements on productity and precision. The concept of HSM, tool materials and tool wear of HSM, surface roughness of HSM, and the chip shape of HSM are discussed.

• Management & Information Systems Review
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• v.34 no.3
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• pp.125-140
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• 2015

KOSDAQ market reorganized their division system from two types to four types of division departments such as blue chip, venture, medium, and technology development departments in 2011. However, under the current new division system, financially unhealthy firms attempting to take advantage of the classifying opportunity of blue chip department are likely to engage in pernicious earnings management. The objective of this study is to investigate the earnings management behavior surrounding the time of KOSDAQ firms entering the blue chip department via new division system. More specifically, we test whether the firms classified blue chip department tend to engage in upward earnings management using accruals and real activities before and after they achieve blue chip status. In this study, we analyzed 111 firms classified blue chip department in 2011 according to new division system in KOSDAQ market. Major test results indicate that firms entering the blue chip department according to current KOSDAQ division system in general, tend to inflate reported earnings by means both of accruals and real activities right before the entering year. This result suggests that the firms classified blue chip department engage in opportunistic earnings management with a view to uplifting their market values. Our study is expected to provide clues useful for searching policy directions which intend to ameliorate adverse side effects of the current KOSDAQ division system. In sum, the regulatory authorities and enforcement bodies need to exercise caution in deliberating more stringent review procedures so that financially healthy and promising candidates are properly segregated from their poor and risky counterparts, thus enhancing the beneficial effects, while mitigating adverse side effects of the system.