• 한국정보통신학회논문지
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• 제9권7호
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• pp.1419-1424
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• 2005

본 논문에서는 통신 채널의 오류로 인하여 통신 단말간에 서로 송수신되는 정보중에 임의의 비트가 삭제되거나 추가되어 암호 알고리즘을 사용하여 통신이 불가능해지는 경우, 이를 극복하기 위한 기법으로 Statistical CFB 방식의 암호 알고리즘을 제안한다. 먼저, 비트 삽입 또는 비트 삭제 발생 시 오류 전파의 영향을 수학적으로 모델링하여 이론적인 Statistical CFB 암호 알고리즘의 성능을 분석한다. 이 경우, Statistical CFB 방식의 성능을 결정하는 요소인 농기 패턴의 길이와 피프백되는 키의 길이를 변화해가며 분석하도록 한다. 또한 이론적인 분석과 함께 실제로 특정 길이의 동기 패턴과 피드백되는 키를 선택한 후, Statistical CFB 방식을 적용한 암호 알고리즘을 사용하여 성능을 분석하였다. 이를 이론적인 분석 결과와 비교하여 제안된 암호 알고리즘의 타당성을 검증한다.

• JSTS:Journal of Semiconductor Technology and Science
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• 제17권2호
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• pp.252-259
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• 2017

In this paper, we propose a novel method for extracting an accurate depth of a trap that causes RTS(Random Telegraph Signal) noise. The error rates of the trap depth rely on the mean time constants and its ratio. Here, we determined how many data of the capture and emission time constant are necessary in order to reduce the trap depth error caused by an inaccurate mean time constant. We measured the capture and emission time constants up to 100,000 times in order to ensure that the samples had statistical meaning. As a result, we demonstrated that at least 1,000 samples are necessary to satisfy less than 10% error for trap depth. This result could be used to improve the accuracy of RTS noise analysis.

• Computers and Concrete
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• 제7권5호
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• pp.469-482
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• 2010

This paper investigates the concrete permeability through a numerical and statistical approach. Concrete is considered as a random heterogeneous composite of three phases: aggregates, interfacial transition zones (ITZ) and matrix. The paper begins with some classical bound and estimate theories applied to concrete permeability and the influence of ITZ on these bound and estimate values is discussed. Numerical samples for permeability analysis are established through random aggregate structure (RAS) scheme, each numerical sample containing randomly distributed aggregates coated with ITZ and dispersed in a homogeneous matrix. The volumetric fraction of aggregates is fixed and the size distribution of aggregates observes Fuller's curve. Then finite element method is used to solve the steady permeation problem on 2D numerical samples and the overall permeability is deduced from flux-pressure relation. The impact of ITZ on overall permeability is analyzed in terms of ITZ width and contrast ratio between ITZ and matrix permeabilities. Hereafter, 3680 samples are generated for 23 sample sizes and 4 contrast ratios, and statistical analysis is performed on the permeability dispersion in terms of sample size and ITZ characteristics. By sample theory, the size of representative volume element (RVE) for permeability is then quantified considering sample realization number and expected error. Concluding remarks are provided for the impact of ITZ on concrete permeability and its statistical characteristics.

• Journal of Biosystems Engineering
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• 제30권5호
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• pp.268-273
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• 2005

This study was conducted to investigate the specificities of four fulcrum types for geo-statistical analysis of elevation within rice paddy field. In Korea, the spaces between inter-rows and between hills for rice transplanting are 30cm and 11cm to 14cm, respectively. So, the size and shape of fulcrum for field elevation measurement should be considered according to the inter-row and the hill spaces. Four kinds of fulcrum were chosen such as round-shape with 2.5cm diameter, circular-shape with 10cm diameter, 10cm (one third of inter-row space) by 24cm (double of hill space) rectangular-shape, and 20cm (two-thirds of inter-row space) by 24cm rectangular-shape. The resulting descriptive statistics couldn't determine the best fulcrum type to measure the rice paddy field elevation. But the results of geo-statistical analysis could determine the best fulcrum type. In the case of 10cm by 24cm rectangular-shape fulcrum, Nugget and range, meaning measurement error and/or noise, and limit of spatial connection, respectively, were minimum; Q value meaning weight of spatial structure and $r^2$ value were minimum, and residual sum of squares was minimum. It means that 10cm by 24 cm rectangular-shape fulcrum could best describe the rice paddy field elevation.

• 대한안전경영과학회지
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• 제16권2호
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• pp.19-29
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• 2014

Korean societal concern for the train accidents is fast and widely increasing with an ever-increasing demand and use for KTX. Most of these train accidents are inclined to be caused by human error. Experts used to attribute the causes of human error to the defects in various aspects such as technology, organizational system, practices, corporate culture, and/or human resource itself. Among the diverse causes of human error, an important one, even though it was rarely focused, may be the issue of impact of rule or procedure change on human error. Giving attention to the implicit importance of this issue, this study intends to highlight the theme of frequent procedure change in railway driving manual as a critical factor of human error. To attain this purpose mentioned above, dual methodologies were adopted. One is to qualitatively analyze the real cases of procedure change in relevant manuals followed by the incident case(passing the station scheduled to stop) happened lately. Another is to quantitatively perform statistical analysis based on questionnaires received from 224 train drivers. Results show that frequent changes in internal affairs procedure is or may be an important factor causing stress and human error from train drivers.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 춘계학술대회
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• pp.19-24
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• 2004

A number of creep data were collected and filed for type 316LN stainless steels through literature survey and experimental data produced in KAERI. Using these data, polynomial equations for predicting creep life were obtained for Larson Miller (L-M), Qrr-Sherby-Dorn (O-S-D) and Manson-Haferd (M-H) parametric methods. In order to find out the suitability for them, the relative standard error (RSE) and standard error of estimate (SEE) values were obtained by statistical process of creep data. The O-S-D parameter showed better fitting to creep-rupture data than the L-M or the M-H parameters, and the three parametric methods did not generate the large difference in the SEE and the RSE values.

• 한국항공운항학회지
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• 제6권1호
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• pp.21-29
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• 1998

The purpose of the present paper is to determine the time required and error tolerance limits for flight data computation. The results of statistical analysis showed that the calculator side computation required about 50 seconds for each question and wind side computation needed about 115 seconds for each question. In case of error tolerance limits, it was found that the error tolerance limit for altitude computation war 90 feet and two knots of interval was recommanded for the speed computation in calculator side, and one degree of interval for heading computation and five knots interval for speed computation in wind side.

• Journal of Information Processing Systems
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• 제14권4호
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• pp.904-915
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• 2018

We demonstrate how social media content can be used to predict the unemployment rate, a real-world indicator. We present a novel method for predicting the unemployment rate using social media analysis based on natural language processing and statistical modeling. The system collects social media contents including news articles, blogs, and tweets written in Korean, and then extracts data for modeling using part-of-speech tagging and sentiment analysis techniques. The autoregressive integrated moving average with exogenous variables (ARIMAX) and autoregressive with exogenous variables (ARX) models for unemployment rate prediction are fit using the analyzed data. The proposed method quantifies the social moods expressed in social media contents, whereas the existing methods simply present social tendencies. Our model derived a 27.9% improvement in error reduction compared to a Google Index-based model in the mean absolute percentage error metric.

• 한국전기전자재료학회논문지
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• 제27권5호
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• pp.328-341
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• 2014

The object of this paper is to develop optimal optical filter, which can be used to identify the financial account and read the information. The five factors which affect the performance of the optical filter are identified as optical glass type, existence of Fe, Photo pic coating type, and coating form. In this study we seek to determine the optimal combination for the best design of the optical filter. For each combination, the performances of optical filter are investigated using the proper experimental equipments and methods. White-state voltage, black-state voltage, and black-state error rate are used for the performance measures. Through the statistical analysis of the performance data collected, we have determined the optimal design of the optical filter.

• Computers and Concrete
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• 제26권3호
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• pp.293-307
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• 2020

The aim of this paper is to develop design-oriented models for the prediction of the ultimate strength and ultimate axial strain for concrete confined with glass fiber-reinforced polymer (GFRP) wraps. Twenty of most used and recent design-oriented models developed to predict the strength and strain of GFRP-confined concrete in circular sections are selected and evaluated basing on a database of 163 test results of concrete cylinders confined with GFRP wraps subjected to uniaxial compression. The evaluation of these models is performed using three statistical indices namely the coefficient of the determination (R²), the root mean square error (RMSE), and the average absolute error (AAE). Based on this study, new strength and strain models for GFRP-wrapped concrete are developed using regression analysis. The obtained results show that the proposed models exhibit better performance and provide accurate predictions over the existing models.