• Proceedings of the Korean Information Science Society Conference
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• 2001.04a
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• pp.646-648
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• 2001

소프트웨어 산업의 급성장에 의해 소프트웨어의 재사용에 대한 요구는 더욱 증가하고 있다. 현재 객체지향 패러다임보다 더 큰 재사용의 규모를 가지는 컴포넌트 기술이 업계에서 점차 각광을 받고 있다. 본 논문에서는 객체지향 언어인 자바언어를 기반으로 개발된 어플리케이션을 자바 분산 컴포넌트 기술은 EJB 기반의 어플리케이션으로 전환하는 기법을 소개하고, 컴포넌트 단위로 구성된 클래스들을 EJB의 빈으로 매핑하는 기법을 제시한다.

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2011.03a
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• pp.71-71
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• 2011

전류를 흘렸을 때 양극과 음극에 따라 움직이는 미세한 나노입자를 이용하여 색, 글자, 그림 등을 표시하는 응용디스플레이 기술이 전기영동디스플레이(electrophoretic display)이다. 최근 전자종이 등 상품화가 진행되면서 전기영동디스플레이에 대한 관심증대와 함께 기술개발이 지속적으로 진행되고 있다. 본 연구에서는 분산중합을 이용하여 $TiO_2$ core 입자에 polystyrene을 shell로 코팅하여 마이크로캡슐형의 전기영동디스플레이에 적합한 입자를 제조하고 성능을 분석하였다. 먼저 분산제의 종류, 모노머의 농도, 개시제의 농도에 따라 제조된 대전복합입자의 크기 및 분포를 보면, 분산제의 종류를 달리 하였을때를 제외하고 대체로 균일하였다. 입경의 변화를 보면, 약 200-300nm의 $TiO_2$가 개질에 의해 400-500nm의 입경을 나타내는 것으로부터 200nm 두께의 shell층을 갖는다는 것을 확인 할 수 있었다. 또한 분산제의 종류에 따라서는 분산제를 사용하지 않는 경우가 오히려 제조된 입자의 분포가 균일함을 알 수 있었고 모노머의 농도에 따른 변화는 볼 수 없었으며 입경분포가 균일한 입자가 제조되었음을 알 수 있었다. 대전복합입자의 TGA 곡선으로부터 $300^{\circ}C$ 부근에서 polystrene shell에 의한 분해를 볼 수 있었고 $600^{\circ}C$ 이후에 잔류된 core의 $TiO_2$ 입자를 확인 할 수 있었다. 이 결과로부터 $TiO_2$ core-polystyrene shell형의 전자 종이용 대전복합입자의 제조를 확인 할 수 있었다. 또한 제조된 대전복합입자의 zeta potential을 보면, (+)전하를 띄며 64.8mV의 비교적 높은 zeta potential을 가지는 것을 확인 할 수 있었다. 그리고 $TiO_2$ 대전복합입자와 같은 방법으로 제조된 흑색 대전복합입자를 혼합하여 cell test를 측정한 결과, cell에 ${\pm}$10V의 저전압을 가했을 때에도 비교적 응답속도가 빠른 입자의 구동현상을 확인 할 수 있었다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.10a
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• pp.966-969
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• 2012

This study suggests a query conversion method based on Topic Maps MetaData Registry(TMDR) in order to solve heterogeneity problems distributed in networks and to integrate data efficiently. In order to integrate distributed data, TMDR provides global schema and it solves heterogeneity problem within local data using query conversion method. After analyzing relationship between Meta Schema Ontology(MSO) of eXtended Meta Data Registry(XMDR) and Topic Maps, this method allows integrated access through Meta Location(ML) which manages accessing information of local data. The processing method is to produce a global query for global processing by using TMDR and then to make the produced global query approach to systems distributed through networks so that allows integrated access at the end. For this, we propose a method to convert a global query into a query which is adaptive to local query.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.2
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• pp.711-718
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• 2017

Silver nanoparticles were attached by chemical reduction after synthesizing a porous PVK-CTA complex. The PVK-CTA complex was synthesized by polymerizing N-vinylcarbazole in a CTA-chloroform solution using iron(III) chloride as an oxidizing agent and a honeycomb-pattern with uniformly formed macropores was formed by applying steam to the complex surface soaked with a volatile solvent under humid conditions. Using TTF as a reducing agent and PVP as a dispersant, silver nanoparticles were attached on the Honeycomb-pattern complex surface through chemical reduction. The formation of the complex was confirmed by FT-IR and UV-Vis spectrometry, and the degree of thermal decomposition of the complexes was analyzed after N-vinylcarbazole was polymerized by varying its concentration. The uniformity of the pores on the composite surface and the dispersibility of the attached silver nanoparticles were investigated by SEM. The dispersibility of the silver nanoparticles was also analyzed by varying the concentrations of reducing agent and dispersant and precursor.

• Journal of the Korean Geotechnical Society
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• v.22 no.12
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• pp.15-24
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• 2006

The evaluation of shear modulus is very important in various fields of civil engineering. Non-destructive seismic methods can be used to determine shear wave velocity ($V_s$) profile. Non-destructive seismic methods geneally consist of three steps: field testing, evaluation of dispersion curve, and determination of Vs profile by inversion process. Non-destructive seismic methods can be divided into two categories according to the number of receivers used for data reduction: two-channel tests and multi-channel tests. Two channel tests use apparent velocity dispersion curve and multi-channel tests use mode dispersion curves. Multi-channel tests using mode dispersion curve can reduce calculation time to determine soil profile and uncertainties in inversion process. So far, only multi-channel tests can determine mode dispersion curves but multi-channel test needs many receivers to determine reasonable mode dispersion curves. In this paper, HWAW (Harmonic Wavelet Analysis of Wave) method is applied to determine mode dispersion curves. HWAW method uses short test setup which consists of two receivers with a spacing of 1 to 3 m. Through numerical simulations and field application, it is shown that HWAW can determine resonable mode disperson curves.

• Journal of the Korean Applied Science and Technology
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• v.33 no.2
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• pp.247-254
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• 2016

Since microzirconia has excellent thermal and mechanical properties with high chemical and electrical resistance, it can be used in various fields. When the surface of zirconia becomes hydrophilic, its dispersibility in water will be improved as well as the resistance to most hydrophobic contaminants will be increased. In this study, we investigated the introduction of a hydrophilic groups on the microzircornia surface through hydrolysis and condensation reactions with two different silanes containing hydrophilic functional groups, such as ${\gamma}$-aminopropyltrimethoxysilane (APS) and ${\gamma}$-ureidopropyltrimethoxysilane (UPS) at different pH and concentration conditions. A covalent bond formation between the surface hydroxyl groups of zirconia and that of hydrolyzed silanes was confirmed by ninhydrin test and FT-IR spectroscopy. However, the presence of Si on the surfaces of both silane modified microzirconias was unable to detect by SEM/EDS technique. In addition, particle size analysis results provide that the size of microzirconia was changed to smaller or bigger than that of original zirconia due to crushing and aggregation during the modification process. The water dispersibility was improved for only APS modifed zirconia (AS-2 and AS-3) under neutral pH condition, but the water dispersibility and stability for all cases of 0.5~2% UPS modifed zirconia (US series) were much improved.

• The Journal of the Acoustical Society of Korea
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• v.41 no.3
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• pp.326-334
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• 2022

In this paper, we propose speech enhancement algorithm as a pre-processing for robust speech recognition in noisy environments. Auxiliary-function-based Independent Vector Analysis (AuxIVA) is performed with weighted covariance matrix using time-varying variances with scaling factor from target masks representing time-frequency contributions of target speech. The mask estimates can be obtained using Neural Network (NN) pre-trained for speech extraction or diffuseness using Coherence-to-Diffuse power Ratio (CDR) to find the direct sounds component of a target speech. In addition, outputs for omni-directional noise are closely chained by sharing the time-varying variances similarly to independent subspace analysis or IVA. The speech extraction method based on AuxIVA is also performed in Independent Low-Rank Matrix Analysis (ILRMA) framework by extending the Non-negative Matrix Factorization (NMF) for noise outputs to Non-negative Tensor Factorization (NTF) to maintain the inter-channel dependency in noise output channels. Experimental results on the CHiME-4 datasets demonstrate the effectiveness of the presented algorithms.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.11
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• pp.6952-6957
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• 2014

In photocatalysis, the addition of metal matter to $TiO_2$ can alter the surface properties. As such, the metal can increase the rate of the photodegradation reaction. In this study, a range of modified $TiO_2$ photocatalysts were prepared and tested to improve the activity of photodegradation at a batch-typed photoreactor. To obtain a good sol solution of the $TiO_2$ photocatalyst, several types of dispersion agents and stabilizers were investigated. The photocatalyst solutions were modified with isoproply alcohol as the dispersion agent and sodium silicate as the stabilizer. The effects of various metallic elements on enhancing the photocatalytic activity of $TiO_2$ on the degradation of toluene were examined. Palladium-added $TiO_2$ was found to be the best, whereas copper or tungsten-added also showed good results. In the case of palladium addition, the increase in removal efficiency was 25%. On the other hand, Fe-added $TiO_2$ showed a notable decrease in photocatalytic degradation. Additional doping of copper or tungsten on the $Pd/TiO_2$ had no positive effect on the photodegradation activity.

• Journal of the Korea Concrete Institute
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• v.18 no.3 s.93
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• pp.379-388
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• 2006

This paper presents a model for evaluating the contribution by arch action to shear resistance in shear-critical reinforced concrete beams. Based on the relationship between shear and bending moment in beams subjected to combined shear and bending, the behavior of a beam is explicitly divided into two base components of the flexural action and the tied arch action. The compatibility condition of the shear deformation that deviates from Bernoulli bending plane is formulated utilizing the smeared truss idealization with an inclined compression chord. The Modified Compression Filed Theory is employed to calculate the shear deformation of the web, and the relative axial displacements of the compression and the tension chord by the shear flow are also calculated. From this shear compatibility condition in a beam, the shear contribution by the arch action is numerically decoupled. Then the validity of the model is examined by applying the model to some selected test beams in literatures. The results may confirm the rationale of the proposed behavioral model.

• The Korean Journal of Financial Management
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• v.10 no.2
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• pp.137-159
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• 1993

본 연구에서는 우리나라의 금융자산, 특히 회사채와 주식이 인플레이션과 관련하여 어떠한 행태를 보이는가를 실증적으로 살펴본다. 1976년부터 1992년까지의 기간중 채권 및 주식수익률에 피서가설이 성립하는가의 여부, 주식수익률과 기대인플레이션과 관련된 Fama의 허구성가설 및 Geske & Roll의 역인과성가설 등을 공적분관계검정 및 VAR모형의 예측오차 분산분해등을 통하여 포괄적으로 결정한다. 이를 위하여 본 연구는 다음과 같은 순서로 진행하였다. 첫째, 단순정태회귀분석을 통하여 우리나라 금융시장에서 주식이나 채권이 기대된 인플레이션이나 예상치 못했던 인플레이션에 대해 얼마나 인플레이션방어수단으로 유효한지를 살펴보았다. 우선, 회사채수익률의 경우 피서가설의 성립을 기각하기 어려웠다. 반면, 주식의 경우에는 피서가설이 성립될 수 없음은 물론이고, 대부분의 선진국가들처럼 기대인플레이션에 주식수익률이 만대방향으로 반응하는 것으로 나타났다. 주식수익률을 설명하는 변수에 예상되는 산업생산증가나 통화량증가를 나타내는 변수들을 추가하여도 주식수익률과 기대인플레이션간의 부의 관계는 여전히 유의적인 것으로 남아있었다. 따라서 파마의 주식수익률과 기대인플레이션간의 허위관계가설은 우리나라 주식시장에서는 적용되지 않는 것으로 나타났다. 둘째, 단순정태분석에서 활용된 여러 회귀식들이 가성적회귀관계(假性的回歸關係)를 나타내는 경우를 확인하기 위하여 공적분관계가 형성되는지를 검정하였다. 그 결과, 회사채수익률과 인플레이션은 공적분관계가설이 기각되지 않았으나, 주식수익률과 기대인플레이션간에는 공적분관계가 나타나지 않았다. 공적분관계에 입각하여 오차수정모형을 추정한 결과, 회사채수익률의 변화는 단기적인 인플레이션의 동태를 예측하는데 있어서 도움을 주지만, 기대인플레이션 및 예상산업생산증가률의 변화는 주식실질수익률의 단기적 동해예측에 개별적으로는 도움이 되지 못하였다. 마지막으로 여러 변수들의 관계를 사전적으로 설정하지 않고 VAR 모형의 오차분해를 통하여 인과관제를 분석한 결과, 주식수익률과 기대인플레이션이 허구적(虛構的)인 관계가 아님을 시사하고 있다. 그러나, 주식수익률변동은 예상산업생산증가에 의하여 어느정도 설명이 가능하고 대부분의 경제변수에 대하여는 외생적인 성격을 강하게 보여주고 있어서, 기대인플레이션과의 인과관계에 있어서도 선행적인 위치를 지지하고 있다.