• 한국지능시스템학회논문지
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• 제13권4호
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• pp.427-432
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• 2003

사람의 뇌 속에 있는 신경 세포들은 여러 정보 처리 활동을 하면서 전기적인 신호를 발생시키는데 이를 두피 표면에서 측정한 것이 뇌파이다. 이러한 뇌파는 임상에서 주로 이용되어 왔으나 근래에는 이러한 뇌파를 이용하여 컴퓨터와 통신하거나 기기를 제어할 수 있는 이른바 BCI(Brain-Computer Interface)에 대한 연구가 대두되고 있다. BCI 연구의 궁극적 목표는 다양한 정신상태에 따른 뇌파의 특성을 파악하여 컴퓨터나 기기 등을 제어하는 것이다. 이를 위하여 본 연구에서는 좀 더 정확하고 신뢰성 있는 기기 제어를 위해 피험자의 의지대로 발생시킨 잡파를 이용하여 방향 제어 시스템을 구현하였다. 뇌파에 포함된 잡파 중 구별될 수 있는 특징을 나타내는 잡파를 선택하고 이들의 패턴을 인식하고 분류한 후 이를 제어신호로 변환하여 방향을 제어하는 시스템을 구현하였다.

• 한국임상수의학회지
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• 제25권3호
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• pp.182-186
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• 2008

An 11-year-old mixed breed male dog was presented with a thoracoabdominal wall mass of 3-year duration. Initial tentative diagnosis of osteosarcoma was made. Despite chemotherapy treatment, 72 days following the date of presentation, the dog was euthanized. Based upon necropsy and histopathologic findings, the tumor was definitely diagnosed as a combined type osteosarcoma of the rib. At necropsy examination, the tumor extended the left kidney and diaphragm, but distant metastasis was not found. The tumor's weight was 2.3kg and that was 38.3% of the dog's weight. This case report describes the clinicopathological, computed tomographic, histopathologic and immunohistochemical findings of extensive rib osteosarcoma in a small breed dog.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 춘계학술대회 논문집 전자세라믹스 센서 및 박막재료 반도체재료 일렉트렛트 및 응용기술
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• pp.84-87
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• 2000

The microwave dielectric properties of complex perovskite-structured $Ba(Mg_{1/3}Ta_{2/3})O_3$ ceramics were investigated with calcining condition. The BMT ceramics were prepared by conventional mixed oxide method. Calcining conditions were $1200^{\circ}C$ for 10hr., $1300^{\circ}C$ for 2hr., and 5hr., respectively. And the specimens were sintered at $1650{\mu}m$. The structural and microwave properties of BMT ceramics were investigated by XRD, SEM and network analyzer. In the case of BMT ceramics calcined at $1300^{\circ}C$ for 5 hr., dielectric constant, quality factor and temperature coefficient of resonant frequency were 20.26, 31,144(at 1GHz), 6.11[ppm/$^{\circ}C$], respectively.

• Journal of Electrical Engineering and Technology
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• 제8권5호
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• pp.991-1001
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• 2013

Instead of building new substations or transmission lines, proper installation of flexible AC transmission systems (FACTS) devices can make the transmission networks accommodate more power transfers with less expansion cost. In this paper, the problem to maximize power system loadability by optimally installing two types of FACTS devices, namely static var compensator (SVC) and thyristor controlled series compensator (TCSC), is formulated as a mixed discrete-continuous nonlinear optimization problem (MDCP). To reduce the complexity of the problem, the locations suitable for SVC and TCSC installations are first investigated with tangent vector technique and real power flow performance index (PI) sensitivity factor and, with the specified locations for SVC and TCSC installations, a set of schemes is formed. For each scheme with the specific locations for SVC and TCSC installations, the MDCP is reduced to a continuous nonlinear optimization problem and the computing efficiency can be largely improved. Finally, to cope with the technical and economic concerns simultaneously, the scheme with the biggest utilization index value is recommended. The IEEE-14 bus system and a practical power system are used to validate the proposed method.

• 한국분말재료학회지
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• 제16권1호
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• pp.33-36
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• 2009

In order to increase the magnetic loss for electromagnetic(EM) wave absorption, the soft magnetic $Fe_{73}Si_{16}B_7Nb_3Cu_1$(at%) alloy strip was used as the basic material in this study. The melt-spun strip was pulverized using an attrition mill, and the pulverized flake-shaped powder was crystallized at $540^{\circ}C$ for 1h to obtain the optimum grain size. The Fe-based powder was mixed with 2 wt% $BaTiO_3$, $0.3{\sim}0.6$ wt% carbon black, and polymer-based binders for the improvement of electromagnetic wave absorption properties. The mixture powders were tape-cast and dried to form the absorption sheets. After drying at $100^{\circ}C$ for 1h, the sheets of 0.5 mm in thickness were made by rolling at $60^{\circ}C$, and cut into toroidal shape to measure the absorption properties of samples. The characteristics including permittivity, permeability and power loss were measured using a Network Analyzer(N5230A). Consequently, the properties of electromagnetic wave absorber were improved with the addition of both $BaTiO_3$ and carbon black powder, which was caused by the increased dielectric loss of the additive powders.

• Computers and Concrete
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• 제4권4호
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• pp.299-316
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• 2007

The compressive strength of concrete is a commonly used criterion in producing concrete. However, the test on the compressive strength is complicated and time-consuming. More importantly, since the test is usually performed 28 days after the placement of the concrete at the construction site, it is too late to make improvements if unsatisfactory test results are incurred. Therefore, an accurate and practical strength estimation method that can be used before the placement of concrete is highly desirable. In this study, the estimation of the concrete strength is performed using support vector regression (SVR) based on the mix proportion data from two ready-mixed concrete companies. The estimation performance of the SVR is then compared with that of neural network (NN). The SVR method has been found to be very efficient in estimation accuracy as well as computation time, and very practical in terms of training rather than the explicit regression analyses and the NN techniques.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제50권8호
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• pp.376-381
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• 2001

The(1-x) MgTiO$_3$-xSrTiO$_3$(x=0.03~0.04) ceramics were fabricated by the conventional mixed oxide method. The structural and microwave dielectric properties were investigated by XRD, SEM, EDS and network analyzer. The sintering temperature and time were 1275$^{\circ}C$~135$0^{\circ}C$ and 2hours, respectively. In the XRD results of 0.96MgTiO$_3$-0.04SrTiO$_3$ceramics, the perovskite structure of SrTiO$_3$and ilmenite structure of MgTiO$_3$phase were coexisted. The dielectric constant($\varepsilon$(sub)${\gamma}$) and temperature coefficient of resonant frequency($\tau$(sub)f) were increased with addition of SrTiO$_3$. In thie case of 0.96MgTiO$_3$-0.04SrTiO$_3$ ceramics sintered at 13$25^{\circ}C$, the dielectric constant, quality factor(Q) and temperature coefficient of resonant frequency($\tau$(sub)f) were 20.13, 7956(at 7.27GHz), and +1.76ppm/$^{\circ}C$, respectively.

• 한국세라믹학회지
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• 제47권2호
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• pp.169-176
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• 2010

The Fe-treated CNT/$TiO_2$ photocatalysts mixed with anatase and rutile phase have been developed for the decomposition of non-biodegradable different organic dyes like methylene blue (MB), rhodamine B (Rh.B), and methyl orange (MO) in two conditions as ultraviolet and visible light respectively. The results indicate that all the Fe-CNT/$TiO_2$ composites proved to be more efficient photocatalysts since degradation of MB at higher reaction rates, tthe decomposition rate of different dyes increases with an increase of $Fe^{3+}$ concentration in composites the highest rate of decomposition of different dyes was noted under UV irradiation. These results can indicate that the large CNT network is facilitate the electron transfer and strongly adsorb dye molecules on the texted photocatalysts, iron is reactive in the photo-Fenton process resulting in high production of OH radicals and also high activity of the photocatalyst. And Fe particles can generate more photoinduced electrons to conduction band of $TiO_2$ under visible light irradiation. The composites of Fe-CNT/$TiO_2$ photocatalysts synthesized by a sol-gel method were characterized by BET, TEM, SEM, XRD and EDX.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2010년도 하계학술대회 논문집
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• pp.85-85
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• 2010

In this paper, each specimen blended at weight proportions of 80% HDPE to 20% EVA, 70% HDPE to 30% EVA, 60% HDPE to 40% EVA, and 50% HDPE to 50% EVA was manufactued respectively. FE-SEM, DSC and XRD analysis were carried out as the means of structural and chemical analysis. From the results of DSC and XRD analysis, the lower contents in blended specimens were, the higher melting temperature and crystallinity of main crystal were. It seems that the phenomena was attributes to themoplastic interpenetrating network effect(TPIPN) in which EVA having low melting point penetrated into HDPE. Also, from the decreasing tendeancy of melting point as a function of blend ration, it was confirmd that above resins have compatibility. The thermal and mechanical performance of proposed insulator were compared with conventional XLPE, main insulating material of CV cable. Also, validity was proved by superior and inferior factor respectively.

• 정보학연구
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• 제2권2호
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• pp.145-161
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• 1999

본 논문에서는 캐리 전파가 없어 고속연산이 가능한 잉여 수 체계를 이용하여 고속으로 동작할 수 있는 역전파 신경회로망을 설계방법을 제안하였다. 설계된 신경회로망은 잉여수계를 이용한 MAC 연산기와 혼합계수 변환을 이용한 시그모이드 함수 연산 부로 구성되며, 설계된 회로는 VHDL로 기술하였고 Compass 툴로 합성하였다. 실험결과, 가장 나쁜 경로일 경우, 약 19nsec의 지연속도를 보였고, 기존의 실수 연산기에 비하여 약 40%정도 하드웨어 크기를 줄일 수 있었다. 본 논문에서 설계한 신경회로망은 실시간 처리를 요하는 병렬분산처리 시스템에 적용될 수 있을 것으로 기대된다.