• Title/Summary/Keyword: Validation

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A Secure Digital Signature Delegation Scheme using CAs (CA를 이용한 안전한 서명 검증 위임 기법)

  • 최연희;박미옥;전문석
    • Journal of the Korea Institute of Information Security & Cryptology
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    • v.13 no.6
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    • pp.55-65
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    • 2003
  • To perform the certificate validation processing on the user-side application induces the very considerable overhead because of the complex and time-consuming characteristic of the validation processing. Especially, the verification for digital signature over a certificate can be the major reason of the overhead, since the verification accompanies with the cryptographic calculation over each certificate on the certificate path. In this paper, we propose a new certificate validation scheme can reduce the overhead caused by user-side certificate validation processing and improve the utilization of CAs. As the result, our proposed scheme can not only reduces the overhead for the validation processing by decreasing the cryptographic calculation but also improves the utilization of CAs by employing them to the validation processing.

Developing a Molecular Prognostic Predictor of a Cancer based on a Small Sample

  • Kim Inyoung;Lee Sunho;Rha Sun Young;Kim Byungsoo
    • Proceedings of the Korean Statistical Society Conference
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    • pp.195-198
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    • 2004
  • One Important problem in a cancer microarray study is to identify a set of genes from which a molecular prognostic indicator can be developed. In parallel with this problem is to validate the chosen set of genes. We develop in this note a K-fold cross validation procedure by combining a 'pre-validation' technique and a bootstrap resampling procedure in the Cox regression . The pre-validation technique predicts the microarray predictor of a case without having seen the true class level of the case. It was suggested by Tibshirani and Efron (2002) to avoid the possible over-fitting in the regression in which a microarray based predictor is employed. The bootstrap resampling procedure for the Cox regression was proposed by Sauerbrei and Schumacher (1992) as a means of overcoming the instability of a stepwise selection procedure. We apply this K-fold cross validation to the microarray data of 92 gastric cancers of which the experiment was conducted at Cancer Metastasis Research Center, Yonsei University. We also share some of our experience on the 'false positive' result due to the information leak.

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Validation Data Augmentation for Improving the Grading Accuracy of Diabetic Macular Edema using Deep Learning (딥러닝을 이용한 당뇨성황반부종 등급 분류의 정확도 개선을 위한 검증 데이터 증강 기법)

  • Lee, Tae Soo
    • Journal of Biomedical Engineering Research
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    • v.40 no.2
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    • pp.48-54
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    • 2019
  • This paper proposed a method of validation data augmentation for improving the grading accuracy of diabetic macular edema (DME) using deep learning. The data augmentation technique is basically applied in order to secure diversity of data by transforming one image to several images through random translation, rotation, scaling and reflection in preparation of input data of the deep neural network (DNN). In this paper, we apply this technique in the validation process of the trained DNN, and improve the grading accuracy by combining the classification results of the augmented images. To verify the effectiveness, 1,200 retinal images of Messidor dataset was divided into training and validation data at the ratio 7:3. By applying random augmentation to 359 validation data, $1.61{\pm}0.55%$ accuracy improvement was achieved in the case of six times augmentation (N=6). This simple method has shown that the accuracy can be improved in the N range from 2 to 6 with the correlation coefficient of 0.5667. Therefore, it is expected to help improve the diagnostic accuracy of DME with the grading information provided by the proposed DNN.

The Precision Validation of the Precise Baseline Determination for Satellite Formation

  • Choi, Jong-Yeoun;Lee, Sang-Jeong
    • Journal of Astronomy and Space Sciences
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    • v.28 no.1
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    • pp.63-70
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    • 2011
  • The needs for satellite formation flying are gradually increasing to perform the advanced space missions in remote sensing and observation of the space or Earth. Formation flying in low Earth orbit can perform the scientific missions that cannot be realized with a single spacecraft. One of the various techniques of satellite formation flying is the determination of the precise baselines between the satellites within the formation, which has to be in company with the precision validation. In this paper, the baseline of Gravity Recovery and Climate Experiment (GRACE) A and B was determined with the real global positioning system (GPS) measurements of GRACE satellites. And baseline precision was validated with the batch and sequential processing methods using K/Ka-band ranging system (KBR) biased range measurements. Because the proposed sequential method validate the baseline precision, removing the KBR bias with the epoch difference instead of its estimation, the validating data (KBR biased range) are independent of the data validated (GPS-baseline) and this method can be applied to the real-time precision validation. The result of sequential precision validation was 1.5~3.0 mm which is similar to the batch precision validation.

Improvement of Neural Network Performance for Estimating Defect Size of Steam Generator Tube using Multifold Cross-Validation (다중겹 교차검증 기법을 이용한 증기세관 결함크기 예측을 위한 신경회로망 성능 향상)

  • Kim, Nam-Jin;Jee, Su-Jung;Jo, Nam-Hoon
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.26 no.9
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    • pp.73-79
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    • 2012
  • In this paper, we study on how to determine the number of hidden layer neurons in neural network for predicting defect size of steam generator tube. It was reported in the literature that the number of hidden layer neurons can be efficiently determined with the help of cross-validation. Although the cross-validation provides decent estimation performance in most cases, the performance depends on the selection of validation set and rather poor performance may be led to in some cases. In order to avoid such a problem, we propose to use multifold cross-validation. Through the simulation study, it is shown that the estimation performance of defect width (defect depth, respectively) attains 94% (99.4%, respectively) of the best performance achievable among the considered neuron numbers.

APPLICATION AND CROSS-VALIDATION OF SPATIAL LOGISTIC MULTIPLE REGRESSION FOR LANDSLIDE SUSCEPTIBILITY ANALYSIS

  • LEE SARO
    • Proceedings of the KSRS Conference
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    • pp.302-305
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    • 2004
  • The aim of this study is to apply and crossvalidate a spatial logistic multiple-regression model at Boun, Korea, using a Geographic Information System (GIS). Landslide locations in the Boun area were identified by interpretation of aerial photographs and field surveys. Maps of the topography, soil type, forest cover, geology, and land-use were constructed from a spatial database. The factors that influence landslide occurrence, such as slope, aspect, and curvature of topography, were calculated from the topographic database. Texture, material, drainage, and effective soil thickness were extracted from the soil database, and type, diameter, and density of forest were extracted from the forest database. Lithology was extracted from the geological database and land-use was classified from the Landsat TM image satellite image. Landslide susceptibility was analyzed using landslide-occurrence factors by logistic multiple-regression methods. For validation and cross-validation, the result of the analysis was applied both to the study area, Boun, and another area, Youngin, Korea. The validation and cross-validation results showed satisfactory agreement between the susceptibility map and the existing data with respect to landslide locations. The GIS was used to analyze the vast amount of data efficiently, and statistical programs were used to maintain specificity and accuracy.

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Method Development and Cross Validation of Analysis of Hydroxylated Polycyclic Aromatic Hydrocarbons (OH-PAHs) in Human Urine (소변 중 다환방향족탄화수소 대사체의 분석법 확립 및 교차분석)

  • Park, Na-Youn;Jeon, Jung-Dae;Koo, Hyeryeong;Kim, Jung Hoan;Lee, Eun-Hee;Lee, Kyungmu;Mun, Cheoljin;Kho, Younglim
    • Journal of Environmental Health Sciences
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    • v.41 no.5
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    • pp.358-367
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    • 2015
  • Objectives: This study was performed to evaluate the analytical method for PAH metabolites in human urine using enzyme hydrolysis and solid-phase extraction coupled with LC-(ESI)-MS/MS technique. Methods: We employed HPLC tandem mass spectrometry techniques with appropriate pre-treatment for analysis of 16 OH-PAHs in human urine. Samples were hydrolysis by ${\beta}$-flucuronidase/Aryl sulfatase, and target compounds were extracted by solid-phase extraction with a strata-x cartridge. Cross-validation was performed between Eulji University and Green Cross laboratories with 200 human urine samples. Results: The accuracies were between 90.3% and 118.8%, and precisions (relative standard deviations) were lower than 10%. The linearity obtained was satisfying for the 16 OH-PAH compounds, with a coefficient of determination ($r^2$) higher than 0.99. The results of cross-validation at the two organizations were compared by ICC (interclass correlation coefficient) values. The cross-validation results were excellent or good for all compounds. Conclusion: An analytical method was validated for low nanogram levels of 16 OH-PAHs in human urine. Also, satisfying results were obtained for method validation such as accuracy, precision and ICC of cross-validation.

Validation Technique of Trace-Driven Simulation Model Using Weighted F-measure (가중 F 척도를 이용한 Trace-Driven 시뮬레이션 모델의 검증 방법)

  • HwangBo, Hoon;Cheon, Hyeon-Jae;Lee, Hong-Chul
    • Journal of the Korea Society for Simulation
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    • v.18 no.4
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    • pp.185-195
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    • 2009
  • As most systems get more complicated, system analysis using simulation has been taken notice of. One of the core parts of simulation analysis is validation of a simulation model, and we can identify how well the simulation model represents the real system with this validation process. The difference between input data of two systems has an effect on the comparison between a simulation model and a real system at validation stage, and the result with such difference is not enough to ensure high credibility of the model. Accordingly, in this paper, we construct a model based on Trace-driven simulation which uses identical input data with the real system. On the other hand, to validate a model by each class, not by an unique statistic, we validate the model using a metric transformed from F-measure which estimates performance of a classifier in data mining field. Finally, this procedure enables precise validation process of a model, and it helps modification by offering feedback at the validation phase.

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Specification Validation Method for Improving KML Interoperability (KML 호환성 개선을 위한 명세서 검증 방안)

  • Kang, Jihun;Kim, Jung Ok;Lee, Jun Seok
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.32 no.4_1
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    • pp.353-361
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    • 2014
  • The study has planned to analyze the most typical specification validation in Korea and the other countries, which shows the well-formed and schema validation, in purpose to enhance users' conveniences. Also, we suggested the validation system to provide the information compatibility regarding to application programs for non-expert. The featured KML specification supported by the VWorld 3D Desktop and the Google Earth. Based on this above estimation, the system has been designed to inform potential problems and the applicability in 3D Desktop and Google Earth for the user. The KML information passed through the proposed validation is simply expressed on the map, so as instructed the information on the program selection and additional details instruct users as a text file. When not being suitable for the proposed program, another program can be considered, and the problems which may be occurred are also announced to increase the compatibility of KML.

An Efficient RDF Query Validation for Access Authorization in Subsumption Inference (포함관계 추론에서 접근 권한에 대한 효율적 RDF 질의 유효성 검증)

  • Kim, Jae-Hoon;Park, Seog
    • Journal of KIISE:Databases
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    • v.36 no.6
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    • pp.422-433
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    • 2009
  • As an effort to secure Semantic Web, in this paper, we introduce an RDF access authorization model based on an ontology hierarchy and an RDF triple pattern. In addition, we apply the authorization model to RDF query validation for approved access authorizations. A subscribed SPARQL or RQL query, which has RDF triple patterns, can be denied or granted according to the corresponding access authorizations which have an RDF triple pattern. In order to efficiently perform the query validation process, we first analyze some primary authorization conflict conditions under RDF subsumption inference, and then we introduce an efficient query validation algorithm using the conflict conditions and Dewey graph labeling technique. Through experiments, we also show that the proposed validation algorithm provides a reasonable validation time and when data and authorizations increase it has scalability.