• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.4
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• pp.375-380
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• 2009

Bit error rate(BER) performance of each bit for hierarchical M-ary phase shift keying(H-MPSK) modulation scheme is changed according to the phase parameters. Thus, a method to find the phase parameters appropriate to the requests of the system is needed. In this paper, we propose a method to obtain the phase parameters from an approximate approach of BER for H-MPSK and verify a validity of the proposed method through the previously provided expression for analyzing an exact error probability of H-MPSK.

• Annual Conference on Human and Language Technology
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• 1998.10c
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• pp.15-19
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• 1998

기계 번역 시스템에서 품사 태거의 오류는 전체번역 정확률에 결정적인 영향을 미친다. 따라서 어휘 단계의 정보만으로는 중의성 해소가 불가능한 단어에 대해서는 중의성 해소에 충분한 정보를 얻을 수 있는 구문 분석이나 의미 분석 단계까지 완전한 중의성 해소를 유보하는 N-best 품사 태거가 요구된다. 또한 N-best 품사 태거는 단어에 할당되는 평균 품사 개수를 최소화함으로써 상위 단계의 부하를 줄이는 본연의 역할을 수행하여야 한다. 본 논문은 통계 기반 품사 태깅 방법을 이용하여 N-best 후보를 선정하고, 선정된 N-best 후보에 언어 규칙을 적용하여 중의성을 감소시키거나 오류를 보정하는 혼합형 N-best 품사 태깅 방법을 제안한다 제안된 N-best 품사 태거는 6만여 단어의 영어 코퍼스에서 실험한 결과, 단어 당 평균 1.09개의 품사를 할당할 때 0.43%의 오류율을 보인다.

• Communications of Mathematical Education
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• v.24 no.3
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• pp.709-730
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• 2010

The inverse function of a one-to-one correspondence is explained with a graph, a numerical formula or other useful expressions. The purpose of this paper is to know how low achieving students understand the learning contents needed reversible thinking about irrational functions. Low achieving students in this study took paper-pencil test and their written answers were collected. They made various mistakes in solving problems. Their error types were grouped into several classes and identified in this analysis. Most students did not connected concepts that they learned in the lower achieving students to think in reverse order in case of and to visualize concepts of functions. This paper implies that it is very important to take into account students' accommodation and reversible thinking activity.

• School Mathematics
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• v.11 no.4
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• pp.643-664
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• 2009

This study was aimed to understand the problems that students experience during the self--directed study of a mathematics digital textbook and to find the implications for the design of digital textbook. For this study, we analyzed the process of self-directed learning on 'division of fractions with same denominator' using digital textbook by eight 6th graders. Students asked to use think aloud method while they study the unit. Their learning process was videotaped and analyzed by researchers after the experiment. After the self-directed learning, students filled out a test items and participated interview with a researcher. The result showed that students experienced several misconceptions and errors while using a digital textbook. The types of misconceptions and errors were cataegorized as "misconceptions and errors caused by a mathematics textbook" and "misconceptions and errors caused by a digital textbook". Especially, students showed several important misconceptions and errors because of the design factors. This implies we need to consider the causes of misconceptions for the design of a digital textbook.

• Korean Educational Research Journal
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• v.39 no.1
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• pp.39-56
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• 2018

The purpose of this study is to examine the comparation Korean "-e(에), -eseo(에서)" with the Chinese "zai(在)," analyze the errors of using "-e(에), -eseo(에서)," and suggest the direction of teaching required for Chinese learners to reduce these errors. Referring to mean place, "-e(에)" and "-eseo(에서)" generally correspond to "zai(在)" in Chinese, but "zai(在)" in Chinese does not completely correspond to "-e(에)" and "-eseo(에서)" with the meaning of position or place. Chinese learners are often misunderstood when they use "-e(에)" and "-eseo(에서)."

• Proceedings of the Korean Nuclear Society Conference
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• 1997.05a
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• pp.444-449
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• 1997

본 논문에서는 기존의 PSA기법인 사건수목/고장수목의 단점을 보완한 동적 신뢰성 평가도구인 DYLAM방법론을 이용해서 참조원전$^{[1]}$ 소외전원 상실사고시 노심노출 사고발생 빈도를 평가하였다. 부분충수 운전시 발생될 수 있는 노심의 노출을 예방하기 위한 운전원의 여러가지 조치들의 오류가능성애 대한 민감도 계산을 수행하였다. 민감도 분석의 결과 일차 충전 및 유출운전 (Feed and B띤) 인적오류가 노심노출 사고발생 빈도에 가장 큰 영향을 미치는 것으로 분석되었으며 정지생각계통 기능회복을 위한 조치는 상대적으로 적은 영향을 끼치는 것으로 나타났다. 또한 정지/저출력으로 운전하는 부분충수 운전시 전 출력에 비하여 노심노출올 무시할 수 없음도 보여주었다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.7A
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• pp.557-567
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• 2005

We evaluate the BER performance of OFDMA system for Wibro services in frequency selective Rayleigh fading channel, considering the carrier frequency offset and the nonlinear high power amplifier. In the uplink OFDMA, nonlinear amplifier and frequency offset introduce larger BER degradation than in the downlink. We explain the reason and obtain the required output back-off of the nonlinear amplifier and value of frequency offset for good BER performance.

• Proceedings of the KAIS Fall Conference
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• 2008.05a
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• pp.220-223
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• 2008

본 논문은 소프트웨어 설계 시 향상된 오류 검출방법을 통해서 소프트웨어 설계의 질을 향상시켜 그에 따른 소프트웨어 제품의 질을 향상시키데 목적을 두고 있다. 또한 소프트웨어 설계 방법론인 MOA(Methodology for Object to Agents)를 기초로 하고 있으며, MOA는 보편적인 정보 모델로써 온톨로지 기반 모델인 OSSD( Ontology for Sortware Specification and Desigh)모델을 이용한다. 본 논문은 OSSD 모델, 뷰-간 비일관성 검사기법, 일관성 프레임워크의 온톨로지적 특성과 연관된 규칙의 조합을 이용하여 UML모델에서 OSSD 모델로의 변환과정에서 수행되는 새로운 형식의 오류 검출방법을 정의한다. OSSD 모델로의 변환과정은 OSSD 모델의 인스턴스를 생성하기 위한 알고리즘에서 복수의 사상테이블을 이용하는 소프트웨어 설계의 어휘분석과 의미분석을 포함한다.

• Communications of Mathematical Education
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• v.38 no.2
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• pp.145-165
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• 2024

The purpose of this study is to analyze the types of errors made by Korean language learners in the use of dual numerals and provides basic data for developing an effective teaching numeration using dual numerals. To this end, a case study was conducted to analyze the types of errors that appear in numeration using dual numerals targeting Korean language learners with diverse linguistic and cultural backgrounds and different academic achievements in Korean and mathematics. Error types that categorized errors made by Korean language learners were used as an analysis framework. The conclusions obtained from the research results are as follows. First, it is necessary to provide students with opportunities to use them frequently so that they can become familiar with the use of native language numerals, which often causes errors. Second, when teaching Korean language learners with low-level Korean language academic achievement how to use Chinese numerals, it is necessary to pay attention to the multiplicative numeral system of Chinese numerals. Third, it is necessary to teach children to accurately read foreign word classifiers used with Chinese numerals accurately in Korean and distinguish between the classifiers 'o'clock' and 'hours'. There is a need to provide guidance so that native language/Chinese numerals can be used appropriately in succession along with Chinese classifiers. The results of this study may contribute to the development of an effective teaching numeration using dual numerals for Korean language learners with diverse linguistic and cultural backgrounds.

• Progress in Medical Physics
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• v.10 no.2
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• pp.95-101
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• 1999

The aims of this report are to classify the incorrect data of patients and the errors of dose and dose distribution observed in QA activities on teleradiotherapy chart, and to analyze their frequency. In our department, radiation physicists check several sheets of patient chart to reduce numeric errors before starting radiation therapy and at least once a week, which include history, port diagram, MU calculation or treatment planning summary and daily treatment sheet. The observed errors are classified as followings. 1) Identity of patient, 2) Omitted or unrecorded history sheet even though not including the item related to dose, 3) Omission of port diagram, or omitted or erroneous data, 4) Erroneous calculation of MU and point dose, and important causes, 5) Loss of summary sheet of treatment planning, and erroneous data of patient in the sheet, 6) Erroneous record of radiation therapy, and errors of daily dose, port setup, MU and accumulated dose in the daily treatment sheet, 7) Errors leading inexact dose or dose distribution, errors not administerd even though its possibility, and simply recorded errors, 8) Omission of sign. Number of errors was counted rather than the number of patients. In radiotherapy chart QA from Jun 17, 1996 to Jul 31, 1999, no error of patient identity had been observed. 431 Errors in 399 patient charts had been observed and there were 405 physical errors, 9 cases of omitted or unrecorded history sheet, and 17 unsigned. There were 23 cases (5.7%) of omitted port diagram, 21 cases (5.2%) of omitted data and 73 cases (18.0 %) of erroneous data in port diagram, 13 cases (3.2 %) treated without MU calculation, 68 cases (16.3 %) of erroneous MU, 8 cases (2.0%) of erroneous point dose, 1 case (0.2 %) of omitted treatment planning summary, 11 cases (2.7%) of erroneous input of patient data, 13 cases (3.2%) of uncorrected record of treatment, 20 cases (4.9%) of discordant daily doses in MU calculation sheet and daily treatment sheet, 33 cases (8.1%) of erroneous setup, 52 cases (12.8%) of MU setting error, 61 cases (15.1%) of erroneous accumulated dose. Cases of error leading inexact dose or dose distribution were 239 (59.0 %), cases of error not administered even though its possibility were 142 (35.1 %), and cases of simply recorded error were 24 (5.9 %). The numeric errors observed in radiotherapy chart ranged over various items. Because errors observed can actually contribute to erroneous dose or dose distribution, or have the possibility to lead such errors, thorough QA activity in physical aspects of radiotherapy charts is required.