• 음성과학
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• 제12권3호
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• pp.105-114
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• 2005

It was verified that a speaker verification system improved its performances of EER by regularizing log likelihood ratio, using background speaker models. Recently the wireless mobile phones are becoming more dominant communication terminals than wired phones. So the need for building a speaker verification system on mobile phone is increasing abruptly. Therefore in this paper, we had some experiments to examine the performance of speaker verification based on mobile phone's voices. Especially we are focused on the performance variations in EER(Equal Error Rate) according to several background speaker's characteristics, such as selecting methods(MSC, MIX), number of background speakers, aging factor of speech database. For this, we constructed a speaker verification system that uses GMM(Gaussin Mixture Model) and found that the MIX method is generally superior to another method by about 1.0% EER. In aspect of number of background speakers, EER is decreasing in proportion to the background speakers populations. As the number is increasing as 6, 10 and 16, the EERs are recorded as 13.0%, 12.2%, and 11.6%. An unexpected results are happened in aging effects of the speech database on the performance. EERs are measured as 4%, 12% and 19% for each seasonally recorded databases from session 1 to session 3, respectively, where duration gap between sessions is set by 3 months. Although seasons speech database has 10 speakers and 10 sentences per each, which gives less statistical confidence to results, we confirmed that enrolled speaker models in speaker verification system should be regularly updated using the ongoing claimant's utterances.

• 간호행정학회지
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• 제14권3호
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• pp.229-240
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• 2008

Purpose: To develop the patient classification system based on the resource utilization for reimbursement of long-term care hospitals in Korea. Method: Health Insurance Review & Assessment Service (HIRA) conducted a survey in July 2006 that included 2,899 patients from 35 long-term care hospitals. To calculate resource utilization, we measured care time of direct care staff (physicians, nursing personnel, physical and occupational therapists, social workers). The survey of patient characteristics included ADL, cognitive and behavioral status, diseases and treatments. Major category criteria was developed by modified delphi method from 9 experts. Each category was divided into 2-3 groups by ADL using tree regression. Relative resource use was expressed as a case mix index (CMI) calculated as a proportion of mean resource use. Result: This patient classification system composed of 6 major categories (ultra high medical care, high medical care, medium medical care, behavioral problem, impaired cognition and reduced physical function) and 11 subgroups by ADL score. The differences of CMI between groups were statistically significant (p<.0001). Homogeneity of groups was examined by total coefficient of variation (CV) of CMI. The range of CV was 29.68-40.77%. Conclusions: This patient classification system is feasible for reimbursement of long-term care hospitals.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2005년도 봄학술 발표회 논문집(II)
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• pp.33-36
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• 2005

Recently, the use of volcanic-ash as a part of cement content in concrete is very common. But, it has been indicated that the compressive strength of concrete using large amount of volcanic-ash as a part of cement content in early age is low and carbonation velocity is fast. To solve those problems, High Volume Volcanic-Ash Concrete which contained large amount of volcanic-ash as a part of fine aggregate has been proposed. This is an experimential study to compare and analyze the properties of High Volumn Volcanic-Ash Concrete according to the replacement method and ratio of volcanic-ash. For this purpose, the mix proportion of concrete according to the replacement method(PL, C10, C150, A10, A100, A150) And then slump, setting time, bleeding, compressive strength, tensile strength and carbornation test were performed. According to test results, it was found that the compressive strength of the concrete using the volcanic-ash as a part of fine aggregate(A) was higher than that of the concrete using the volcanic-ash as a part of cement content(C). And, the compressive strength of the A concrete increased in early age as well as in long tern age as the volcanic-ash content increased.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2006년도 추계 학술논문 발표대회 논문집
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• pp.39-42
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• 2006

In this study, there is purpose that is on a concrete defect happen from aggregate minute's particle mixing in process that make waste concrete as recyclable cement puts to practical use constructing basic data for design of mix proportion used recyclable cement and solves strength fall problem using micron separator, and does general recyclable cement high quality. As a result of X-ray diffraction(XRD) of rater HR-C than NR-C is aware that it come out the micron-separating to decrease the $SiO_2$-peak below 50%. And a construction field which apply for strength's $24{\sim}28MPa$ HR-C in order to realize NR-C of 44% and 51%. Recycle concrete capacity through improved recycle cement of manufacturing technique by micron-separating's new distribution more better improvement. Therefore, in this study, it need to more various study a recycle cement of high quality for reasonable and utility recycling than disposal concrete.

• Toxicological Research
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• 제18권2호
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• pp.129-138
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• 2002

The mouse lymphoma assay (MLA) has been recently validated as a sensitive and specific test system to determine the genotoxic potential for a chemical. The objective of this study is to evaluate the utility of MLA for detecting mutagens. Especially, to compare MLA with the in vitro chromosomal aberration test (CA), we performed MLA using the microwell method with three chemicals (hydroxyurea, theophylline and amino acid copper complex), which were reportedly positive in the CA. In cell treated with hydroxyurea, anti-neoplastic agent that blocks DNA replication, evidence of a positive response was obtained without S9 mix for 4 h and 24 h. In addition, analysis of colony size distribution at concentration that gave an elevated mutant fraction showed that hydroxyurea induced a high proportion of small type colonies, indicating that hydroxyurea-induced mutation is associated with large chromosomal deletion. Conversely, negative MLA result was obtained for theophylline, which was wed as central nervous system stimulator. Although theophylline increased the mutant frequency at concentration of 1250 $\mu\textrm{g}$/$\textrm{m}{\ell}$ with S9 mix for 4 h, a concentration-related increase in mutant frequency was not observed. The MLA result of amino acid copper complex was considered equivocal because the positive result was obtained at concentration showing 10% or less RS or RTG. Thus, among 3 CA-positive chemicals, positive MLA result was obtained for one. The other two chemicals were negative and equivocal. However MLA, which evaluates mutagenic potential of chemicals through colony formation by cell grouth, may provide a higher predictivity of carcinogenesis than CA.

• Smart Structures and Systems
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• 제17권1호
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• pp.73-89
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• 2016

The stress dependence of ultrasonic wave velocity is known as the acoustoelastic effect. This effect is useful for stress monitoring if the acoustoelastic coefficient of a subject medium is known. The acoustoelastic coefficients of metallic materials such as steel have been studied widely. However, the acoustoelastic coefficient of concrete has not been well understood yet. Basic constituents of concrete are water, cement, and aggregates. The mix proportion of those constituents greatly affects many mechanical and physical properties of concrete and so does the acoustoelastic coefficient of concrete. In this study, influence of the water-cement ratio (w/c ratio) and the fine-coarse aggregates ratio (fa/ta ratio) on the acoustoelastic coefficient of concrete was investigated. The w/c and the fa/ta ratios are important parameters in mix design and affect wave behaviors in concrete. Load-controlled uni-axial compression tests were performed on concrete specimens. Ultrasonic wave measurements were also performed during the compression tests. The stretching coda wave interferometry method was used to obtain the relative velocity change of ultrasonic waves with respect to the stress level of the specimens. From the experimental results, it was found that the w/c ratio greatly affects the acoustoelastic coefficient while the fa/ta ratio does not. The acoustoelastic coefficient increased from $0.003073MPa^{-1}$ to $0.005553MPa^{-1}$ when the w/c ratio was increased from 0.4 to 0.5. On the other hand, the acoustoelastic coefficient changed in small from $0.003606MPa^{-1}$ to $0.003801MPa^{-1}$ when the fa/ta ratio was increased from 0.3 to 0.5. Finally, it was also found that the relative velocity change has a linear relationship with the stress level of concrete.

• 한국구조물진단유지관리공학회 논문집
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• 제26권6호
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• pp.139-147
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• 2022

이 연구에서는 다양한 결합재를 혼합하여 고강도 저알칼리형 인공어초용 시멘트 복합체를 설계하고 ME 방식 3D 프린터 출력 가능성을 평가했다. 그 결과, 3D 프린팅이 가능하도록 시멘트 복합체의 유동성을 조절하기 위해서는 물-결합재비, 규사-결합재비, 규사의 종류 등을 제어하는 것이 중요한 것으로 판단된다. 출력이 가능한 정도의 흐름값을 달성한 뒤 3D 프린터 출력물의 표면품질을 양호하게 유지하기 위해서는 증점제 첨가량을 조절하는 것이 필요하다. 또한, 알파형 반수석고를 사용한 배합에서는 급결효과를 제어하기 위해 응결조절제를 사용해야하며 이 배합의 흐름값을 유지하는 시간을 도출하여 출력시 적용하는 것이 필요하다. 재료의 요구 강도를 얻기 위해서는 우선 출력이 가능한 수준의 유동성을 만족시킨 후, 배합을 조정하면 가능하다. 알파형 반수석고를 포함한 다성분계 결합재의 사용으로 저알칼리형 인공어초용 3D 프린팅 배합을 설계하고 출력성을 확인하였으나, 알칼리 저감 효과를 정량적으로 평가하기 위해서는 추후 연구가 필요하다.

• 한국GIS학회:학술대회논문집
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• 한국GIS학회 2004년도 GIS/RS 공동 춘계학술대회 논문집
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• pp.493-498
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• 2004

The objective of the present study is to compare various conventional and recently evolved satellite image-processing techniques and to ascertain the best possible technique that can identify and position of aquaculture farms accurately in and around the Younggwang coastal area. Several conventional techniques performed to extract such information fiom the Landsat-TM imagery do not seem to yield better information about the aquaculture farms, and lead to misclassification. The large errors between the actual and extracted aquaculture farm information are due to existence of spectral confusion and inadequate spatial resolution of the sensor. This leads to possible occurrence of mixture pixels or 'mixels' of the source of errors in the classification techniques. Understanding the confusing and mixture pixel problems requires the development of efficient methods that can enable more reliable extraction of aquaculture farm information. Thus, the more recently evolved methods such as the step-by-step partial spectral end-member extraction and linear spectral unmixing methods are introduced. The farmer one assumes that an end-member, which is often referred to as 'spectrally pure signature' of a target feature, does not appear to be a spectrally pure form, but always mix with the other features at certain proportions. The assumption of the linear spectral unmxing is that the measured reflectance of a pixel is the linear sum of the reflectance of the mixture components that make up that pixel. The classification accuracy of the step-by-step partial end-member extraction improved significantly compared to that obtained from the traditional supervised classifiers. However, this method did not distinguish the aquaculture ponds and non-aquaculture ponds within the region of the aquaculture farming areas. In contrast, the linear spectral unmixing model produced a set of fraction images for the aquaculture, water and soil. Of these, the aquaculture fraction yields good estimates about the proportion of the aquaculture farm in each pixel. The acquired proportion was compared with the values of NDVI and both are positively correlated (R$^2$ =0.91), indicating the reliability of the sub-pixel classification.ixel classification.

• 콘크리트학회논문집
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• 제22권2호
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• pp.171-177
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• 2010

최근 내구수명기간 동안 요구되는 성능을 만족시키는 차세대 구조설계 연구의 일환으로 PBD 방법에 대한 관심이 증가하고 있다. 성능의 유효여부를 결정하는 방법 중의 하나인 Bayesian 방법은 일반적으로 내진해석 및 설계에서 많이 사용되어왔다. 이 방법은 어느 지진가속도로 인해 발생할 수 있는 구조물의 한계상태(i.e. 붕괴)의 초과확률을 체계적으로 계산할 수 있는 통계방법이다. 이 연구에서는 Bayesian 방법을 활용하여 콘크리트 배합에 대한 강도, 워커빌리티, 탄산화 등과 같은 재료성능의 만족도를 만족 비율로 계산할 수 있는 PBD 개념을 개발하고자 한다. 설계 또는 분석에 사용될 수 있는 Bayesian 방법은 다양한 재료의 특성을 고려하여 만족도 곡선 작성 과정을 설명하고 작성된 만족도 곡선을 사용하는 방법을 제시하고자 한다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2008년도 추계 학술발표회 제20권2호
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• pp.957-960
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• 2008

최근 초고층 건축물 등에 적용되는 고강도콘크리트의 내화성능에 대한 문제점이 제기됨에 따라 국토해양부에서는 고강도콘크리트 내화성능 관리 기준을 고시한 바 있으며, 건설업계에서도 이에 대응하기 위해 다양한 기술 검토가 이루어지고 있다. 본 연구에서는 고강도콘크리트의 취약점으로 제기되고 있는 화재시의 폭렬문제에 대한 대응방안으로서 기존 연구를 통해 내화성능이 우수한 것으로 보고되고 있는 ECC 를 영구거푸집으로 활용한 고강도콘크리트의 내화성능을 검토하였다.ECC 영구거푸집을 활용한 고강도콘크리트 기둥부재의 내화성능 검토 결과, 영구거푸집과 고강도콘크리트 계면으로의 열 침투를 제어할 수 있도록 부재 생산 및 구축 방안을 검토하고, ECC의 적정 배합 및 두께를 확보한다면 고강도콘크리트의 내화성능 확보기술로서의 활용이 가능할 것으로 판단된다. 또한, 내화성 영구거푸집으로서의 단순 활용 방안 이외에 ECC의 우수한 물리적 성능을 활용하여구조성능을 분담할 수 있는 방안으로의 지속적 검토가 필요할 것으로 판단된다.