• Ocean and Polar Research
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• 제34권2호
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• pp.185-195
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• 2012

This paper focused on forecasting a short-term production of oysters, which have been farmed in Korea, with distinct periodicity of production by year, and different production level by month. To forecast a short-term oyster production, this paper uses monthly data (260 observations) from January 1990 to August 2011, and also adopts several econometrics methods, such as Multiple Regression Analysis Model (MRAM), Seasonal Autoregressive Integrated Moving Average (SARIMA) Model, and Vector Error Correction Model (VECM). As a result, first, the amount of short-term oyster production forecasted by the multiple regression analysis model was 1,337 ton with prediction error of 246 ton. Secondly, the amount of oyster production of the SARIMA I and II models was forecasted as 12,423 ton and 12,442 ton with prediction error of 11,404 ton and 11,423 ton, respectively. Thirdly, the amount of oyster production based on the VECM was estimated as 10,425 ton with prediction errors of 9,406 ton. In conclusion, based on Theil inequality coefficient criterion, short-term prediction of oyster by the VECM exhibited a better fit than ones by the SARIMA I and II models and Multiple Regression Analysis Model.

• 한국전자통신학회논문지
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• 제7권5호
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• pp.1053-1059
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• 2012

바코드 레이블은 저비용과 편리함으로 인해 물품의 식별을 위해 널리 사용되고 있다. 바코드 레이블은 실링인쇄(seal printing)를 통해 대량으로 생산되는데 그 과정에서 인쇄 품질이 좋지 않거나 레이블 내의 바코드와 텍스트가 서로 일치하지 않는 불량품이 발생하기도 한다. 불량 레이블은 인식 불량 및 업무 오류를 가져오고 이로 인해 물류 지체 및 처리비용 증가를 가져온다. 본 논문에서는 이미지 처리기술을 이용하여 생산단계에서 레이블을 검사하는 온라인 바코드 품질 검사 시스템을 제안한다. 제안 시스템은 카메라에 의해 얻은 이미지를 사용하여 바코드의 품질과 데이터와의 일치성을 검증하고, 불량레이블이 발견되면 경고 신호와 함께 불량임을 표시하여 불량품이 조기에 제거되도록 한다.

• 말소리와 음성과학
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• 제9권4호
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• pp.9-17
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• 2017

The aim of this study is to examine whether Chinese Korean learners (CKL) can correctly produce the aspiration in 'a lenis obstruents /k/, /t/, /p/, /ʧ/+/h/ sound' sequence at the lexical and post-lexical level. For this purpose 4 Korean native speakers (KNS), 10 advanced and 10 intermediate CKL participated in a production test. The material analyzed consisted of 10 Korean sentences in which aspiration can be applied at different prosodic boundaries (syllable, word, accentual phrase). The results showed that for KNS and CKL, the rate of application of aspiration was different according to prosodic boundaries. Aspiration was more frequently applied at the lexical level than at the post-lexical level and it was more frequent at the word boundary than at the accentual phrase boundary. For CKL, pronunciation errors were either non-application of aspiration or coda obstruent omission. In the case of non-application of aspiration, CKL produced the target syllable as an underling form and they did not transform it as a surface form. In the case of coda obstruent ommision, most of the errors were caused by the inherent complexity of phonological process.

• 말소리와 음성과학
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• 제12권1호
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• pp.1-9
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• 2020

The perceptual assimilation of a nonnative phonological contrast can change with linguistic experience, resulting in naïve listeners and novice second language (L2) learners potentially assimilating the members of a nonnative contrast to different native (L1) categories. While it has been shown that this sort of change can affect the discrimination of the nonnative contrast, it has not been tested whether such a change could have consequences for the production of the contrast. In this study, L1 speakers of Mandarin Chinese who were (1) naïve to Korean, (2) novice L2 learners, or (3) advanced L2 learners participated in a Korean non-word repetition task using word-initial sibilants. The initial CVs of their repetitions were then played to L1 Korean listeners who categorized the initial consonant. The naïve talkers were more likely to repeat an initial /s^ha/ as an affricate, whereas the L2 learners repeated it as a fricative, in line with how these listeners have been shown to assimilate Korean sibilants to Mandarin categories. This result suggests that errors in the production of new words presented auditorily to nonnative listeners may be driven by how they perceptually assimilate the nonnative sounds, emphasizing the need to better understand what drives changes in perceptual assimilation that accompany increased linguistic experience.

• 음성과학
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• 제12권4호
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• pp.183-195
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• 2005

In the present study, we investigated development of verb inflections or endings in 3- to 5-year old Korean-speaking children using 28 action verbs for both comprehension and production tasks. For each verb, a l0-second long motion picture and a sheet of paper with three random-ordered color pictures representing 'before, in the middle of, at the end of' the action were generated. A past tense inflection' -et ta,' two present progressive verb endings '-enta' & '-ko itta.' a future tense ending '-elyeko hanta' were tested. In the comprehension task, children were asked to point to a picture correctly representing the tense of a presented verb. In the production task, children were asked to produce a verb with correctly marking the tense of a presented picture. The order of the two tasks were counterbalanced across the children, and the motion pictures were only presented in the first task. Across the ages, the performance accuracies on both comprehension and production tasks were the highest for the past tense marking followed by two present progressive and future tense markings. For each verb endings, the changes of accuracies across ages were analyzed in both tasks. The types of errors for production tasks were also reported.

• 한국초전도ㆍ저온공학회논문지
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• 제18권3호
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• pp.21-24
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• 2016

Recently, production technique and property of the High-Temperature Superconductor (HTS) tape have been improved. Thus, the study on applying an HTS magnet to the high magnetic field application is rapidly increased. A Nuclear Magnetic Resonance (NMR) spectrometer requires high magnitude and homogeneous of central magnetic field. However, the HTS magnet has fabrication errors because shape of HTS is tape and HTS magnet is manufactured by winding HTS tape to the bobbin. The fabrication errors are winding error, bobbin diameter error, spacer thickness error and so on. The winding error occurs when HTS tape is departed from the arranged position on the bobbin. The bobbin diameter and spacer thickness error occur since the diameter of bobbin and spacer are inaccurate. These errors lead magnitude and homogeneity of central magnetic field to be different from its ideal design. The purpose of this paper is to investigate the effect of winding error, bobbin diameter error and spacer thickness error on the central field and field homogeneity of HTS magnet using the virtual NMR signals in MATLAB simulation.

• 품질경영학회지
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• 제24권4호
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• pp.190-206
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• 1996

In case measurements are made on units of production in time order, it is reasonable to expect that the measurement errors will sometimes be first order autocorrelated, and a technique to test such autocorrelation is required to give good control of the productive process. Tool-wear process provide an example for which regression model can sometimes be useful in modeling and controlling the process. For the control of such process, we present a simple method for testing first order autocorrelation in regression errors. The method is based on Bayesian test method via Bayes factor and derived by observing that in general, a Bayes factor can be written as the product of a quantity called the Savage-Dickey density ratio and a correction factor ; both terms are easily estimated from Gibbs sampling technique. Performance of the method is examined by means of Monte Carlo simulation. It is noted that the test not only achieves satisfactory power but eliminates the inconvenience occurred in using the well-known Durbin-Watson test.

• 한국정밀공학회지
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• 제32권7호
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• pp.643-651
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• 2015

Multi-axis magnetic and accelerometer sensor are widely used in consumer product such as smart phones. The vector output of multi-axis sensors have errors on each axis such as offset error, scale error, non-orthogonality. These errors cause many problems on the performance of the applications. In this paper, we designed the effective inline compensation algorithm for calibrating of 3 axis sensors using ellipsoid for mass production of multi-axis sensors. The outputs with those kinds of errors can be modeled by ellipsoid, and the proposed algorithm makes sequential mappings of the virtual ellipsoid to perfect sphere which is calibrated function of the sensor on three-dimensional space. The proposed calibrating process composed of four main stages and is very straightforward and effective. In addition, another imperfection of the sensor such as the drift from temperature can be easily inserted in each mapping stage. Numerical simulation and experimental results shows great performance of the proposed compensation algorithm.

• 시스템엔지니어링학술지
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• 제11권1호
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• pp.67-72
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• 2015

It has been tested for SW reliability in order to prevent the SW error during the development of weapons systems. According to a recent report, defects such as memory leak, buffer overflow, and null deference occur usually in the development stage, but also in the mass production stage. Although it is intended to enhance the SW test and evaluation to prevent SW failures in the development stage, the non-functional problems like syntax errors are not completely revised due to the limitation of the schedule and costs. In addition, SW failure rate are usually fluctuated by the operational environment through SW upgrade in contrast with HW. In this paper, we propose a method to increase SW reliability in the mass production stage of Korean weapon systems.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2001년도 추계학술대회(한국공작기계학회)
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• pp.85-90
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• 2001

Recent general Press brake has many problems in cutting high accurate products in the progress of industry. Previous hand-operated press brake needs many pre-processing works to adjust bending ang1e and marking-off works to calculate bending length. Also, the hand-operating work makes many geometric errors and has difficulty for variety-mass production. To solve these problems, this paper proposes Computer Numerical Control (CNC) general press brake and development of servo-control system based on database for reduction of geometric errors and pre-processing work time and high accuracy bending work.