• Journal of Magnetics
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• 제12권1호
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• pp.40-44
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• 2007

The Planar Hall effect in a spin valve structure has been applied as a biosensor being capable of detecting $Dynabeads^{(R)}$ M-280. The sensor performance was tested under the application of a DC magnetic field where the output signals were obtained from a nanovoltmeter. The sensor with the pattern size of $50{\times}100{\mu}m^2$ has produced high sensitivity; especially, the real-time profiles by using that sensor revealed significant performance at external applied magnetic field of around 7.0 Oe with the resolution of 0.04 beads per $\mu m^2$. Finally, a successful array including 24 patterns with the single sensor size of $3{\times}3{\mu}m^2$ has shown the uniform and stable signals for single magnetic bead detection. The comparison of this sensor signal with the others has proved feasibility for biosensor application. This, connecting with the advantages of more stable and high signal to noise of PHR sensor's behaviors, can be used to detect the biomolecules and provide a vehicle for detection and study of other molecular interaction.

• Design & Manufacturing
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• 제15권2호
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• pp.63-69
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• 2021

Springback is an essential task to be solved in order to make high-precision products in sheet metal forming. In this study, materials with four different elastic regions were used. For the forming analysis, the change of springback caused by the frictional force generated in the flange part during hat shape forming was considered by using the AutoForm analysis program. Factors affecting frictional force were blank holder force, friction coefficient, bead R and bead height. As a result of the forming analysis, the springback increases as the material with a larger elastic region increases. In addition, as the frictional force of the flange part increased, the tensile force in the forming direction increased and the springback decreased. In particular, the blank holder force and friction coefficient had a great effect on springback in mild materials (DC04, Al6016), and the bead effectively affects all materials. Through this study, it was considered that the springback decreased as the material with a smaller elastic region and the tensile force in the forming direction increased.

• 한국환경농학회지
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• 제5권2호
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• pp.113-118
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• 1986

주요(主要) 패류(貝類) 서식지중(棲息地中) 서남해안(西南海岸) 4개지역(個地域)을 선정(選定), 1983년 8월부터 10월에 걸쳐 저니토(底泥土) 시료(試料)118점(點)을 채취(採取), gas chromatograph에 의하여 유기염소계(有機鹽素系) 농약(農藥)의 잔류량(殘留量)을 분석(分析)한 결과(結果) ${\alpha}-BHC,\;{\gamma}-BHC$와 PCNB, heptachlor, ${\alpha}-endosulfan,\;{\beta}-endosulfan,$ p, p'-DDE, dieldrin, o, p'-DDT 및 p, p'-DDT 등(等)이 M$2{\sim}98%$의 검출빈도(檢出頻度)를 보였고 그 평균잔류수준(平均殘留水準)은 ${\gamma}-BHC$와 $PCNB>{\alpha}-BHC>heptachlor{\approx}{\alpha}-endosulfan{\approx}\;p,\; p'-DDE{\approx}dieldrin{\approx}{\beta}-endosulfan{\approx}\;o,\;p'-DDT{\approx}\;p,\;p'-DDT$순(順)으로 $trace{\sim}0.04ppm$범위(範圍)였다. 지역별(地域別) 총잔류량(總殘留量)의 평균(平均)은 강진(康津), 광양(光陽), 여천(麗川) 및 영광(靈光)이 각각(各各) 0.058, 0.080, 0.016 및 0.075ppm이었다. DC-200 column을 사용(使用)하여 ${\gamma}-BHC$와 PCNB의 peak를 분리(分離)하였고 PCNB는 이를 환원(還元) 유도체(誘導體)인 PCA로 만들어 동정(同定)함으로써 공시시료중(供試試料中) PCNB가 잔류(殘留)됨을 확인(確認)하였다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권4호
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• pp.2060-2077
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• 2019

Recently, mobile healthcare services have attracted significant attention because of the emerging development and supply of diverse wearable devices. Smartwatches and health bands are the most common type of mobile-based wearable devices and their market size is increasing considerably. However, simple value comparisons based on accumulated data have revealed certain problems, such as the standardized nature of health management and the lack of personalized health management service models. The convergence of information technology (IT) and biotechnology (BT) has shifted the medical paradigm from continuous health management and disease prevention to the development of a system that can be used to provide ground-based medical services regardless of the user's location. Moreover, the IT-BT convergence has necessitated the development of lifestyle improvement models and services that utilize big data analysis and machine learning to provide mobile healthcare-based personal health management and disease prevention information. Users' health data, which are specific as they change over time, are collected by different means according to the users' lifestyle and surrounding circumstances. In this paper, we propose a prediction model of user physical activity that uses data characteristics-based long short-term memory (DC-LSTM) recurrent neural networks (RNNs). To provide personalized services, the characteristics and surrounding circumstances of data collectable from mobile host devices were considered in the selection of variables for the model. The data characteristics considered were ease of collection, which represents whether or not variables are collectable, and frequency of occurrence, which represents whether or not changes made to input values constitute significant variables in terms of activity. The variables selected for providing personalized services were activity, weather, temperature, mean daily temperature, humidity, UV, fine dust, asthma and lung disease probability index, skin disease probability index, cadence, travel distance, mean heart rate, and sleep hours. The selected variables were classified according to the data characteristics. To predict activity, an LSTM RNN was built that uses the classified variables as input data and learns the dynamic characteristics of time series data. LSTM RNNs resolve the vanishing gradient problem that occurs in existing RNNs. They are classified into three different types according to data characteristics and constructed through connections among the LSTMs. The constructed neural network learns training data and predicts user activity. To evaluate the proposed model, the root mean square error (RMSE) was used in the performance evaluation of the user physical activity prediction method for which an autoregressive integrated moving average (ARIMA) model, a convolutional neural network (CNN), and an RNN were used. The results show that the proposed DC-LSTM RNN method yields an excellent mean RMSE value of 0.616. The proposed method is used for predicting significant activity considering the surrounding circumstances and user status utilizing the existing standardized activity prediction services. It can also be used to predict user physical activity and provide personalized healthcare based on the data collectable from mobile host devices.

• 한국산업보건학회지
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• 제29권2호
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• pp.185-194
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• 2019

Objective: This study was conducted to investigate the intensity of the extremely low frequency magnetic fields(ELF-MF) generated inside of the cabins during subway operation. Methods: The ELF-MF intensity were investigated on 30 subway lines in Korea, including in the Greater Seoul Metropolitan Area(Seoul and Gyeonggi-do Province), Incheon, Busan, Daegu, Daejeon, and Gwangju. ELF-MF intensity was measured at 0.9 m from the floor using EMDEX II meters with a resolution of $0.01{\mu}T$. All data were collected every three seconds and analyzed with EMCALC 2013 version 3.0B software. Basic characteristics of subway operation, including alternative current(AC) or direct current(DC), voltage level, and opening year of the line were investigated. Real-time information during measurement, such as the time of departure, moving and arrival of trains, were also recorded. Results: The arithmetic mean(AM) and maximum(Max) intensity of ELF-MF were $0.62{\mu}T$ and $11.51{\mu}T$, respectively. Compared by region, the ELF-MF intensity measured inside cabin were the highest in the Seoul Metropolitan Area($AM=0.80{\mu}T$), followed by Busan($AM=0.30{\mu}T$), Daegu($AM=0.29{\mu}T$), Incheon($AM=0.14{\mu}T$), Gwangju($AM=0.04{\mu}T$) and Daejeon($AM=0.03{\mu}T$). The average ELF-MF level measured in AC trains($AM=1.36{\mu}T$) was also significantly higher than in DC trains($AM=0.28{\mu}T$). In terms of the opening year of the subway, trains opened before 1990($AM=0.85{\mu}T$) was the highest and the lowest was 2000-2009($AM=0.24{\mu}T$). Conclusions: The AC supply has the greatest influence on the generation of the ELF-MF intensity in subway cabins.

• 전기화학회지
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• 제11권2호
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• pp.89-94
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• 2008

GNP(Glycine Nitrate Process)을 이용하여$(La_{0.75}Sr_{0.25})_{1-x}FeO_{3-\delta}$를 합성하고, perovskite의 A-site deficiency에 따른 특성을 분석하기 위해 x=0, 0.02, 0.04, 0.06, 0.08로 바꾸어 합성하였다. SEM과 XRD분석을 통하여 균질하고 결정성이 높은 분말이 합성된것을 확인하였으며, 4단자법과 AC impedance spectroscopy를 통하여 전도도는 x = 0.02가 $750^{\circ}C$ $155{\Omega}cm^2$로 가장 우수하였으며, AC impedance결과 역시 x = 0.02가 가장 낮은 분극저항과 활성화 에너지를 가지고 있었다. 이 결과 Perovskite의 A-site deficiency를 가함에 따라 산소 결핍 및 구조의 변화가 생겼으며 이로 인해 전도도와 분극 저항, 활성화 에너지에 영향을 미친 것을 알 수 있었다.

• 전자공학회논문지CI
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• 제37권1호
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• pp.55-63
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• 2000

본 논문은 영상 프레임간 차분 성분을 이용한 3D-DCT의 부영역 분할에 따르는 압축효과를 고찰하였다. 제안한 알고리즘은 연속되는 9개의 프레임 그룹단위를 이용하여 8개의 차분 성분을 큐빅블록(8${\times}$8${\times}$8) 형태로 나타낸 정보를 3차원 DCT를 취한 후 부대역으로 분할하려 압축하는 방법이다. 프레임간 시${\cdot}$공간의 주파수 성분을 가지고 8개의 차분 프레임을 DCT한 주파수 영역에서 영상 정보는 저주파 영역인 큐빅블록의 모서리 부분에 집중하므로 효율적인 압축데이터를 얻기 위해 시간축 방향의 프레임 성분블록( 8${\times}$8 블록)을 4${\times}$4 부블록으로 나누었다. 여기서, 이 부블록의 가중치를 이용하여 저주파 부분에 대한 가변적 부영역을 적용시켜 압축율을 높였다. 모의실험에서 비교적 단순한 영상과 고주파 성분을 많이 포함하는 복잡한 영상을 이용하여 복원된 영상의 해상도와 압축율로 비교 평가하였다. 그 결과 평균 0.04-0.05bpp의 압축범위에서 각각의 영상에 대하여 평균적으로 34.75dB와 30.36dB의 높은 압축효과를 얻을 수 있었다.

• 한국결정학회지
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• 제7권1호
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• pp.36-43
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• 1996

Tris(ethylenediamine)nickel(II)Dichromate [Ni(C2N2H8)3]·Cr2O7착화합물 및 결정의 구조를 X-선 회절법으로 연구하였다. 이 결정은 단사정계이고, 공간군은 P21/b(군번호=14)이다. 단위세포길이는 a=8.268(2), b=13.865(2), c=14.921(2)Å, γ=102.04(2)°, V=1672.9(5)Å3, Z=4, Dc=1.806 gcm-3, μ=24.05 cm-0.1이다. 회절반점들의 세기는 흑연 단색화 장치가 있는 자동4축 회절기로 얻었으며 Mo-Kα X-선(λ=0.7107Å)을 사용하였다. 구조분석은 중원자법으로 풀었으며, 최소자승법으로 정밀화 하였을 때, 최종 신뢰도 값들은 2248개의 회절반점에 대하여 R=0.045, Rw=0.051, Rall=0.059 및 S=2.171이었다. 니켈 착이온 가운데 하나의 에칠렌디아민 고리중에서 두 개의 탄소원자가 무질서하게 상호교차하는 네 개의 원자로 나타났다. 무질서한 에칠렌디아민의 두가지 고리구조들의 α- 과 β- 각들이나 수소결합들을 고려하였을 때 Ni-착이온의 입체구조는 Λδδδ-와 Λδδλ- 구조들의 무질서배열로 보아진다.

• 한국수산과학회지
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• 제19권5호
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• pp.477-484
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• 1986

The interaction of myofibrillar protein with lipid or oxidized lipid was considered to be mostly contributing to the drop of digestibility of fish meat products. The digestibility of myofibrillar protein was $92.11\%$ for flounder and $88.04\%$ for hairtail fish, repectively, and as a rule it decreased as both the amount of lipid and reaction time increased. It also decreased with increase in the amount of added linoleate and oxidized linoleate. However, when the reaction continued for 6 hours or more the digestibility rather increased, which was provably due to the unfolding of protein structure. The hot air dried hairtail fish showed the lowest C-PER values among all dried fish products. The protein quality of flounder, hairtail fish and their dried ones except hot air dried ones measured by C-PER procedure were superior to that of ANRC casein. DC-PER values of all samples were greater than those of C-PER values and the greater discrepancies were noted in hairtail fish (fatty fish) products which possessed the lower in vitro protein digestibilities. Predicted diegstibilities, which were calculated using amino acid profiles, of all samples except raw ones were overestimated in comparison with in vitro protein digestibilities. From the observations so far, formation of complex of lipids and protein was thought to be the most important factor in lowering protein digestibility of the dried fish meat products.

• JSTS:Journal of Semiconductor Technology and Science
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• 제15권5호
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• pp.490-496
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• 2015

We have grown AlN/GaN heterostructure which is a promising candidate for mm-wave applications. For the growth of the high quality very thin AlN barrier, indium was introduced as a surfactant at the growth temperature varied from 750 to $1070^{\circ}C$, which results in improving electrical properties of two-dimensional electron gas (2DEG). The heterostructure with barrier thickness of 7 nm grown at of $800^{\circ}C$ exhibited best Hall measurement results; such as sheet resistance of $215{\Omega}/{\Box}$electron mobility of $1430cm^2/V{\cdot}s$, and two-dimensional electron gas (2DEG) density of $2.04{\times}10^{13}/cm^2$. The high electron mobility transistor (HEMT) was fabricated on the grown heterostructure. The device with gate length of $0.2{\mu}m$ exhibited excellent DC and RF performances; such as maximum drain current of 937 mA/mm, maximum transconductance of 269 mS/mm, current gain cut-off frequency of 40 GHz, and maximum oscillation frequency of 80 GHz.