• Proceedings of the KIEE Conference
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• 2006.07b
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• pp.667-668
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• 2006

최근 반도체산업과 광산업 분야에서 고정도의 위치제어 및 고출력 구동이 가능한 초음파 리니어 모터에 대한 관심이 증가되고 있다. 저자는 공진시스템으로 지지하는 고출력 초음파 리니어 모터를 제안해왔다. 이 모터 시스템은 주목할만한 동작 안정성과 제어능력을 달성 하였지만 모터의 공진 주파수가 예압, 열등의 외부의 요인에 의해 변하게 될 때, 모터는 공진 시스템에 의한 지지 메커니즘이 고정된 공진 주파수만을 가지게 되어 안정적인 구동을 이루기 어렵게 되었다. 본 연구는 고강성 지지를 위해 한 진동자에 세 지지점을 가지는 새로운 모터를 설계 하여 시스템의 위치제어 능력에 대해 조사 하였다. 고강성을 띄는 세점 지지부는 모터를 확실히 지지 할 수 있지만, 진동 모드에 영향을 미치지 않는다. 20 mm의 지름을 가지는 모터를 이용하여 기계적 최대 출력은 75N, 무부하 최대속도 0.45 m/s를 달성하였다. PID 피드백 제어 시스템을 적용시켜 6 kg의 스테이지를 100 nm의 정도를 가지고 200 mm/s로 위치 제어를 달성하였다.

• Journal of the Korean Society for Precision Engineering
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• v.28 no.3
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• pp.275-284
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• 2011

The accuracy simulation technology of linear motion system is introduced in this paper. Motion errors and positioning errors are simulated using informations on the design parameters of elements of linear motion system. 5 Degree-of-freedom motion error analysis algorithm utilizing the transfer function method and positioning error analysis algorithm which are main frame of accuracy simulation are introduced. Simulated motion errors are compared with experimental results for verifying the effectiveness. Then, using the proposed algorithms, simulation is performed to investigate the effects of ballscrew and linear motor on the motion errors. Finally, the influence of feedback sensor position on the positioning error is also discussed.

• Journal of Microbiology and Biotechnology
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• v.22 no.2
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• pp.226-229
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• 2012

Bacterial hemoglobin from Vitreoscilla (VHb) is recognized as a good fusion protein for the soluble expression of foreign protein. In this study, we generated a monoclonal antibody (MAb) against VHb for its detection. For the rapid screening of MAb, a protein chip technology based on the Alexa-488 (A488) dye labeling method was introduced. In order to fabricate the chip, the VHb protein was chemically coupled to the chip surface and then the culture supernatants of 84 hybridoma cell lines were spotted onto the VHb chip. The bound MAbs were measured by A488-modified anti-mouse IgG. A single spot (MAb A10) exhibited significantly high signal intensity. The immunoblot analysis evidenced that the MAb A10 can detect VHb-fused proteins with high specificity.

• Environmental Engineering Research
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• v.15 no.1
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• pp.15-21
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• 2010

This study was conducted to evaluated seawater bacteria and their seasonal characteristics in the arsenic contaminated coastal seawater of Yeosu Bay, the Republic of Korea. Arsenite-oxidizing bacteria play an important role in the seawater of the arsenic contaminated bay, with a variety of arsenic resistance system (ars) genotypes being present during summer. Specifically, Bacillus sp. strain SeaH-As22w (FJ607342), isolated from the bay, were found to contain the arsB, arrA and aoxR type operons, which are involved in arsenic resistance. The isolated bacteria showed relatively high tolerance to sodium arsenite (III; $NaAsO_2$) at concentrations as high as 50 mM. Additionally, batch seawater experiments showed that Bacillus sp. strain SeaH-As22w completely oxidized 1 mM of As (III) to As (V) within 10 days. Ecologically, the arsenic-oxidizing potential plays an important role in arsenic toxicity and mobility in As-contaminated coastal seawater of Yeosu Bay during all seasons because it facilitates the activity of Bacillus sp. groups.

• Journal of the Korean Magnetic Resonance Society
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• v.10 no.2
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• pp.197-202
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• 2006

[ $^{11}B$ ] nuclear magnetic resonance (NMR) measurements were performed on the single crystals of $TbB_4$ to investigate local electronic structure and 4f spin dynamics. $^{11}B$ NMR spectrum, Knight shift, spin-lattice and spin-spin relaxation rates were measured down to 4K at 8T. $^{11}B$ NMR shift and linewidth are huge and strongly temperature dependent due to the 4f moments. In addition, both are proportional to magnetic susceptibility, indicating that the hyperfine field at the boron site originates from the 4f spins of Tb. Below $T_N$, the single broad resonance peak of $^{11}B$ NMR splits into several peaks reflecting the local magnetic fields due to antiferromagnetic spin arrangements. The longitudinal and the transverse relaxation rates, $1/T_1\;and\;1/T_2$, independent of temperature above $T_N$, decreases tremendously confirming huge suppression of spin fluctuation below $T_N$.

• Journal of Information Processing Systems
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• v.14 no.1
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• pp.79-100
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• 2018

Twitter is one of the most popular social platforms for online users to share trendy information and views on any event. Twitter reports an event faster than any other medium and contains enormous information and views regarding an event. Consequently, Twitter topic summarization is one of the most convenient ways to get instant gist of any event. However, the information shared on Twitter is often full of nonstandard abbreviations, acronyms, out of vocabulary (OOV) words and with grammatical mistakes which create challenges to find reliable and useful information related to any event. Undoubtedly, Twitter event summarization is a challenging task where traditional text summarization methods do not work well. In last decade, various research works introduced different approaches for automatic Twitter topic summarization. The main aim of this survey work is to make a broad overview of promising summarization approaches on a Twitter topic. We also focus on automatic evaluation of summarization techniques by surveying recent evaluation methodologies. At the end of the survey, we emphasize on both current and future research challenges in this domain through a level of depth analysis of the most recent summarization approaches.

• Parasites, Hosts and Diseases
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• v.53 no.2
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• pp.223-226
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• 2015

We report here a case of strongyloidiasis in a 72-year-old diabetic patient (woman) accompanied by gastrointestinal stromal tumor receiving imatinib therapy, first diagnosed as hypereosinophilic syndrome and treated with steroids for uncontrolled eosinophilia. She suffered from lower back pain and intermittent abdominal discomfort with nausea and diagnosed with gastrointestinal stromal tumor. After post-operative imatinib treatment eosinophilia persisted, so that steroid therapy was started under an impression of hypereosinophilic syndrome. In spite of 6 months steroid therapy, eosinophilia persisted. Stool examination was performed to rule out intestinal helminth infections. Rhabditoid larvae of Strongyloides stercoralis were detected and the patient was diagnosed as strongyloidiasis. This diagnosis was confirmed again by PCR. The patient was treated with albendazole for 14 days and her abdominal pain and diarrhea improved. This case highlights the need for thorough investigation, including molecular approaches, to test for strongyloidiasis before and during steroid therapies.

• 한국신재생에너지학회:학술대회논문집
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• 2006.06a
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• pp.214-217
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• 2006

p-type 비정질 실리콘 에미터와 n-type 실리콘 기판의 계면에 intrinsic 비정질 실리콘을 증착함으로써 계면의 재결합을 억제하여 20%가 넘는 효율을 보이는 이종접합 태양전지가 Sanyo에 의해 처음 제시된 후 intrinsic layer에 대한 연구가 많이 진행되어 왔다. 하지만 p-type wafer의 경우는 n-type에 비해 intrinsic buffer의 효과가 미미하거나 오히려 특성을 저하시킨다는 보고가 있으며 그 이유로는 minority carrier에 대한 barrier가 상대적으로 낮다는 것과 partial epitaxy가 발생하기 때문으로 알려져 있다. 본 연구에서는 partial epitaxy를 억제하기 위한 방법으로 증착 온도를 낮추고 QSSPC를 사용하여 minority carrier lifetime을 측정함으로써 각 온도에 따른 passivation 특성을 평가하였다. 또한 SiH4에 H2를 섞어서 증착하였을 경우 각 dilution ratio(H2 flow/SiH4 flow)에서의 passivation 특성 또한 평가하였다. 기판 온도 $100^{\circ}C$에서 증착된 샘플의 lifetime이 가장 길었으며 그 이하와 이상에서는 lifetime이 감소하는 경향을 보였다 낮은 온도에서는 박막 자체의 결함이 증가하였기 때문이며 높은 온도에서는 partial epitaxy의 영향으로 추정된다. H2 dilution을 하여 증착한 샘플의 경우 SiH4만 가지고 증착한 샘플보다 훨씬 높은 lifetime을 가졌다 이 또한 박막 FT-IR결과로부터 H2 dilution을 한 경우 compact한 박막이 형성되는 것을 확인할 수 있었는데 radical mobility 증가에 의한 박막 특성 향상이 원인으로 생각된다.

• Journal of the Optical Society of Korea
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• v.15 no.1
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• pp.96-102
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• 2011

Simultaneous measurements using a scanning spectrograph system and transmissometer were performed for the first time over an urban site in Gwangju, Korea, to derive the ambient $NO_2$ volume mixing ratio. The differential slant column densities retrieved from the scanning spectrograph system were converted to volume mixing ratios using the light traveling distance along the scanning line of sight derived from the transmissometer light extinction coefficients. To assess the performance of this system, we compared the derived $NO_2$ volume mixing ratios with those measured by an in situ chemiluminescence monitor under various atmospheric conditions. For a cloudless atmosphere, the linear correlation coefficient (R) between the two data sets (i.e., data derived from the scanning spectrograph and from the in situ monitor) was 0.81; the value for a cloudy atmosphere was 0.69. The two sets of $NO_2$ volume mixing ratios were also compared for various wind speeds. We also consider the measurement errors, as estimated from an error propagation analysis.

• Environmental Engineering Research
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• v.23 no.4
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• pp.420-429
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• 2018

Soil stabilization is a soil remediation technique that reduces the mobility of heavy metals in soils. Although it is a well-established technique, it is nonetheless essential to perform a follow-up chemical assessment via a leaching test to evaluate the immobilization of heavy metals in the soil matrix. Unfortunately, a standard chemical assessment is not sufficient for evaluation of the biological functional state of stabilized soils slated for agricultural use. Therefore, it is useful to employ a pyrosequencing-based microbial community analysis for the purpose. In this study, a recently stabilized site in the proximity of an exhausted mine was analyzed for bacterial diversity, richness, and relative abundance as well as the effect of environmental factors. Based on the Shannon and Chao1 indices and rarefaction curves, the results showed that the stabilized layer exhibited lower bacterial diversity than control soils. The prevalence of dominant bacterial populations was examined in a hierarchical manner. Relatively high abundances of Proteobacteria and Methylobacter tundripaludum were observed in the stabilized soil. In particular, there was substantial abundance of the Methylobacter genus, which is known for its association with heavy metal contamination. The study demonstrated the efficacy of (micro)biological assessment for aiding in the understanding and post-management of stabilized soils.