• 한국통신학회논문지
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• 제27권1A호
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• pp.18-25
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• 2002

본 논문에서는 AWGN 채널환경에서 직렬연접 길쌈부호(serial concatenated convolutional codes; SCCC)의 세 가지 형태에 대한 성능을 비교 및 분석한다. 모의실험 결과 낮은 신호 대 잡음비(signal-to-noise ratio; SNR) 영역에서는 첫 번째 형태의 성능이 가장 우수하였다. 그러나 높은 SNR 영역에서는 세 번째 형태의 성능이 가장 우수함을 아 수 있었다. 그리고 첫 번째 형태에서는 SNR과 반복복호 횟수를 증가시키더라도 성능이 더 이상 향상되지 않는 오류마루(error floor)가 발생하였다. 그러나 두 번째와 세 번째 형태는 높은 SNR에서 반복복호를 5회 이상 수행하더라도 성능이 계속 향상되며 오류마루가 나타나지 않았다. 그리고 SNR이 증가할수록 세 가지 직렬연접 길쌈부호의 BER 성능은 각각의 상위경계(upper bound) 성능에 근접해짐을 알 수 있었다. 또한 자유거리(free distance)가 가장 큰 세 번째 직렬연접 길쌈부호가 세 가지 구조 중에서 가장 우수한 상위경계 성능을 나타내었다.

• 한국측량학회지
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• 제39권5호
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• pp.253-263
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• 2021

Traffic data collected using advanced equipment are highly valuable for traffic planning and efficient road operation. However, there is a problem regarding the reliability of the analysis results due to equipment defects, errors in the data aggregation process, and missing data. Unlike other detectors installed for each vehicle lane, radar detectors can yield different error types because they detect all traffic volume in multilane two-way roads via a single installation external to the roadway. For the traffic data of a radar detector to be representative of reliable data, the error factors of the radar detector must be analyzed. This study presents a field survey of variables that may cause errors in traffic volume collection by targeting the points where radar detectors are installed. Video traffic data are used to determine the errors in traffic measured by a radar detector. This study establishes three types of radar detector traffic errors, i.e., artificial, mechanical, and complex errors. Among these types, it is difficult to determine the cause of the errors due to several complex factors. To solve this problem, this study developed a radar detector traffic volume error analysis model using a multiple linear regression model. The results indicate that the characteristics of the detector, road facilities, geometry, and other traffic environment factors affect errors in traffic volume detection.

• 한국초등수학교육학회지
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• 제24권1호
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• pp.1-30
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• 2020

본 연구는 통계적 소양 교육을 실천하기 위해 초등학교 통계교육의 주된 내용 요소에 해당하는 그래프 지도 중 특히 오류의 유형화에 주목하였다. 구체적으로 문헌 분석을 통해 통계적 문제해결의 관점에서 그래프의 교수학적 의의와 구성 요소를 확인하였고, 이를 표현하는 과정에서 나타나는 오류를 분류하여 각 사례들을 자료 분석 단계에서의 통계 윤리 문제와 연결하였다. 연구 결과, 그래프 오류 유형은 범주 표현에서의 오류, 빈도 표현에서의 오류, 맥락 제시에서의 오류로 분류할 수 있었고, 이러한 오류로 인해 자료 분석 단계에서 주관적인 분석 방법 채택, 시각적 착시현상 유도, 자료에 대한 정보 왜곡과 같은 통계 윤리 문제가 발생할 수 있음을 확인하였다. 그리고 우리나라 초등학교 수학과 교육과정에서는 오류를 범하지 않도록 정형화된 틀을 제공하고 그 틀에 맞춰 그래프를 그리는 절차에 주목하는 경향이 있었다. 이를 통해 그래프 오류 유형이 초등학교 통계교육에 제공하는 시사점을 통계적 소양 교육, 통계 윤리, 교사 지식의 관점에서 제시하였다.

• 한국조사연구학회:학술대회논문집
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• 한국조사연구학회 2002년도 추계학술대회 발표논문집
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• pp.255-274
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• 2002

We classify rotation sampling designs into two classes. The first class replaces sample units within the same rotation group while the second class replaces sample units between different rotation groups. The first class is specified by the three-way balanced design which is a multi-level version of previous balanced designs. We introduce an extended generalized composite estimator (EGCE) and derive its variance and mean squared error for each of the two classes of design, cooperating two types of correlations and three types of biases. Unbiased estimators are derived for difference between interview time biases, between recall time biases, and between rotation group biases. Using the variance and mean squared error, since any rotation design belongs to one of the two classes and the EGCE is a most general estimator for rotation design, we evaluate the efficiency of EGCE to simple weighted estimator and the effects of levels, design gaps, and rotation patterns on variance and mean squared error.

• 한국축산식품학회지
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• 제21권2호
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• pp.163-168
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• 2001

This study was conducted to analyze the errors occurred between standard plate count(SPC) and Bactometer, Malthus, Bactoscan and to investigate correlation coefficient(r) between SPC and each equipments for the purpose of making new calibration curve. Correlation coefficients of three different types of equipments to SPC value were 0.71, 0.81, 0.84 respectively(n=287) and that of three types of equipments were 0.71∼0.82 relatively low. In raw milk, correlation coefficients of three types of equipments of SPC were in the range of 0.67∼0.73 below 3.0${\times}10^4$(CUF/ml) of bacterial number, and those between the three types of equipments were 0.68∼0.72. Between 3.0${\times}10^4$∼5.0${\times}10^5$(CFU/ml) of bacterial number, correlation coefficients of the three different types of equipments were 0.71∼0.81. and those between the three different types of equipments were 0.64∼0.77. Over 5.0${\times}10^5$(CFU/ml), correlation coefficient of the three types equipments were 0.66∼0.83 and those between them were 0.70∼0.85 respectively. The error of the three different types equipments to SPC value was significantly high, 37∼53% of them was under 50% of error range, and in case of raw milk less than 3.0${\times}10^4$ of bacterial number, 44∼67% of them showed over 100% of error.

• 국제학술발표논문집
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• The 9th International Conference on Construction Engineering and Project Management
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• pp.67-73
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• 2022

Construction bid documents contain various errors or discrepancies giving rise to uncertainties. The errors/discrepancies/ambiguities in the bid document, if not identified and clarified before the bid, may cause dispute and conflict between the contracting parties. Given the fact that bid document is a major resource in estimating construction costs, inaccurate information in bid document can result in over/under estimating. Thus, any questions from bidders related to the errors in the bid document should be clarified by employers before bid submission. This study aims to examine the pre-bid queries, i.e., pre-bid request for information (RFI), from state DoTs of the United States to investigate error types most frequently encountered in bid documents. For the study, around 200 pre-bids RFI were collected from state DoTs and were classified into several error types (e.g., coordination error, errors in drawings). The analysis of the data showed that errors in bill of quantities is the most frequent error in the bid documents followed by errors in drawing. The study findings addressed uncertainty types in construction bid documents that should be checked during a bid process, and, in a broader sense, it will contribute to advancing the construction management body of knowledge by clarifying and classifying bid risk factors at an early stage of construction projects.

• 대한기계학회논문집A
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• 제20권3호
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• pp.945-959
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• 1996

In this paper, a comprehensive computer model is described which can be used to generate the volumetric error map combining the machine parametric errors and the measurement prove error, for most types of CMMs and axis configurations currently in use.

• 말소리와 음성과학
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• 제7권2호
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• pp.3-8
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• 2015

Denasalization that nasals are replaced by stops is an unusual error pattern related to manner of articulation. The purpose of this study is to investigate the prevalence of denasalization and to scrutinize the nasal production according to phonological context for typically developing children and children with speech sound disorders(SSD). 220 typically developing children and 48 SSD children from 2~6 years of age were tested with a formal word test, and those who demonstrate denasalization were selected. In addition, the nasal production of SSD children with denasalization were analyzed for the correctness and the error types using the formal word test and spontaneous conversation. The results were as follows: (1) Denasalization was shown in below 10% of 2-3 years of age with typically developing children and in above 20% of 2-5 years of age with SSD. (2) The SSD children who demonstrate denasalization were categorized into 4 types according to the error context of nasals; nasal errors with all word positions, nasal errors with word-final and word-medial positions, nasal errors with word-medial position preceding vowels, and nasal errors with word-medial position preceding obstruents. These results indicate that denasalization is a clinically important error pattern, and word-medial position preceding obstruents is an essential context for denasalization in terms of Korean phonotactics.

• 한국정밀공학회지
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• 제22권4호
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• pp.159-166
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• 2005

This study deals with the correction of gear tooth profile error by finish roll forming. First, we experimentally confirmed that the tooth profile error is a synthesis of the concave error and the pressure angle error. Since various types of tooth profile errors appear in the experiments, we introduced evaluation parameters for rolling gears to objectively evaluate profile quality. Using these evaluation parameters, we clarified the relationship among the tooth profile error, the addendum modification factor (A. M. factor), and the tool loading force. We verified the character of concave error, pressure angle error, tool loading force and number of cycles of finish roll forming by using a forced displacement method. This study makes clear that tool loading force and number of cycles of finish roll forming are very important factors that affect involute tooth profile error. The results of the experiment and analysis show that the proposed method reduces concave and pressure angle errors.

• 대한안전경영과학회:학술대회논문집
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• 대한안전경영과학회 2011년도 추계학술대회
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• pp.551-556
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• 2011

This research presents an implementation strategy of Process Capability Index (PCI) according to the types of process characteristics. The types of process feature are classified as four perspectives of variation range, time period, error position, and process stage. The paper examines short-term or long-term PCI, within or between variation, position of precision or accuracy, and inclusion of measurement or calibration stage. Moreover, the study proposes normality test of unilateral PCI.