• Journal of Gifted/Talented Education
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• v.20 no.3
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• pp.1027-1037
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• 2010

Comparing to the other subject, the relationship among physics contents is strong from the perspective of knowledge order as grades go up. That is, The things already that students learned, are learning and will learn are closed related from grade to grade. We expect students to be proactive and creative in studying physics, which is the goal of 21th century, analyzing their knowledge structure based on the knowledge order through assessment. Especially, using computer system, we provide students with substantial feedback for the assessment as well as objective validity is increased along with speedy and exact process in a bid to help students' mathematical understanding grow. This paper seeks to analyze the data from assessment applying knowledge spaces of the scientifical gifted in the force and the motion concept to applicate on teaching method.

• Korean Journal of Remote Sensing
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• v.22 no.4
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• pp.275-284
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• 2006

The noise sources of a Hyperion image are mainly due to the atmospheric effects, the sensor's instrumental errors, and A/D conversion. Though uncalibrated, overlapping, and all deep water absorption bands generally are removed, there still exist noisy bands. The visual inspection for selecting clean and stable processing bands is a simple practice, but is a manual, inefficient, and subjective process. In this paper, we propose that the extrema ratio be used for noise estimation and unsupervised band selection. The extrema ratio was compared with existing SNR and entropy measures. First, Gaussian, salt and pepper, and Speckle noises were added to ALI (Advanced Land Imager) images with relatively low noises, and the relation of noise level and those measures was explored. Second, the unsupervised band selection was performed through the EM (Expectation-Maximization) algorithm of the measures which were extracted from a Hyperion images. The Hyperion data were classified into 5 categories according to the image quality by visual inspection, and used as the reference data. The experimental result showed that the extrema ratio could be used effectively for band selection of Hyperion images.

• Proceedings of the Korea Water Resources Association Conference
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• 2019.05a
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• pp.16-16
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• 2019

기후변화 시나리오 및 계절예측 자료를 포함한 기후정보를 수자원 분야에 활용하기 위해서는 기후정보의 시 공간적인 상세화(donwscaling)을 필요로 한다. 상세화의 경우 역학적 상세화와 통계학적 상세화로 구분될 수 있으며, 통계학적 상세화를 위해서는 대상 지역의 기후특성을 대표할 수 있는 장기 관측 자료의 확보가 중요하다. 국내의 경우에는 자동기상관측장비(Automatic Weather System, AWS)와 종관기상관측장비(Automatic Synoptic Observation System, ASOS)로 부터 수집된 기상관측자료를 사용할 수 있으나 기후변화 시나리오의 통계적 상세화를 위해서는 30년 이상의 자료 기간을 포함하는 ASOS 자료가 적합하다. 하지만 개발도상국과 같이 기상관측기반이 열악한 지역에서는 잦은 결측 등으로 인하여 품질이 좋은 관측자료의 획득이 어려운 상황이다. 따라서 본 연구에서는 측이 포함된 장기 기상관측 자료로부터 대상 지역의 기후특성을 재현할 수 있도록 기본적인 QC(Quality Control)을 거쳐 결측 자료를 보완할 수 있는 기법 및 R 기반패키지를 개발하여 적용성을 평가하였다. 개발된 기법의 적용성 평가를 위해서 기상청에서 QC를 통해 제공하고 있는 60개 ASOS 지점의 관측자료 중 강수량과 기온 변수를 사용하였다. 최대 50%까지의 현실적인 결측 패턴을 임의로 생성하기 위해 실제 개발도상국 관측자료의 일단위 결측 패턴을 이용하였다. 자료의 QC는 관측일 누락/중복 및 문자형 관측값 등 기본적인 오류 검사, 기온의 경우 물리적 허용 범위에 대한 검사, 최고기온과 최저기온의 비교 및 계측기 오작동에 의한 동일한 값의 반복 등을 포함한 내적 일치성 검사를 우선적으로 수행한다. 이후 결측값에 대해서 인근 기상관측소와의 상관성 분석 결과를 기반으로 결측값을 채우고, 최종적으로는 다양한 위성자료 및 재분석 자료 중에서 일단위 기후특성의 재현성 평가를 통해 선정된 격자형 자료와의 상관성 분석 결과를 기반으로 결측값을 보정하였다. 기온의 경우는 결측률이 높더라도 월평균 기후특성에 큰 영향을 미치지 않았지만 강수의 경우에는 5% 이상의 결측이 발생하는 경우 월평균 강수량에 영향을 미쳐 지역의 강수량을 과소 추정하는 결과를 보였다. 개발된 QC 기법을 강수 자료에 적용한 결과 월평균 기후특성을 잘 복원하는 결과를 보였지만, 일단위 강우 사상의 재현에 있어서는 미흡한 결과를 보였다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2022.05a
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• pp.381-383
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• 2022

This study evaluated the completeness of emergency medical service (EMS) activity reports. In all, 67,830 cases of normal transfers were statistically analyzed using IBM SPSS Statistics version 22, and statistical significance was set at p <0.5. The 119EMT_2 certificate was omitted in 50,037 (73.8%) cases, followed by time-related items in 1,227 (1.8%) cases. In the primary assessment of vital signs, systolic blood pressure was omitted and erroneous in 1,218 (1.9%) and 1,129 (1.8%) cases, respectively. In the secondary assessment, the completeness of all vital sign items was approximately 70%. As the severity of the patient's condition increased, the errors in the EMS activity report also increased, at a significant level (p=.00). Paramedics must be aware of the importance of completing the activity report.

• The Korean Journal of Applied Statistics
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• v.35 no.6
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• pp.685-701
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• 2022

FDR is widely used in high-dimensional data inference since it provides more liberal criterion contrary to FWER which is known to be very conservative by controlling Type-1 errors. This paper proposes a sparse VHAR model estimation method controlling FDR by adapting the knockoff introduced by Barber and Candès (2015). We also compare knockoff with conventional method using adaptive Lasso (AL) through extensive simulation study. We observe that AL shows sparsistency and decent forecasting performance, however, AL is not satisfactory in controlling FDR. To be more specific, AL tends to estimate zero coefficients as non-zero coefficients. On the other hand, knockoff controls FDR sufficiently well under desired level, but it finds too sparse model when the sample size is small. However, the knockoff is dramatically improved as sample size increases and the model is getting sparser.

• Journal of Sasang Constitutional Medicine
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• v.28 no.1
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• pp.51-56
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• 2016

Objectives This study was to identify the types of errors in the statistical analysis and trends of previous reported papers that used various statistical techniques.Methods We have selected 118 original articles for statistical review from the OASIS(http://oasis.kiom.re.kr) and the Pubmed(http://www.pubmed.gov) in the field of Sasang constitutional medicine. Published year was restricted from 2011 to 2015.Results 1. The ANOVA(25.72%) was the statistic of choice overall, followed by the chi-square test(21.74%), regression analysis(14.13%), t-test(11.59%), and etc. 2. By examining the errors of the statistical methods, there were 42(59.2%) thesis with errors among 71 thesis using ANOVA, 19(31.7%) thesis among 60 thesis using chi-square test, and 35(89.7%) over 39 thesis using regression analysis.Conclusions To improve the quality of Sasang Constitution, the participation of statisticians in research design will reduce the significant errors in statistical interpretation of the results.

• 한국정보통신설비학회:학술대회논문집
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• 2004.08a
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• pp.298-301
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• 2004

KT는 무궁화 3호 위성을 이용한 양방향 위성 통신 사업을 추진하고 있으며, 지상망을 이용하기 어려운 지역에 정부/공공, 에너지 산업, 기업 단일망 등 다양한 산업 분야를 대상으로 초고속 네트워크를 제공하고 있다. 양방향 위성 통신 서비스는 36,000km 상공의 위성 중계기와 지상 간의 통신 지연을 극복하기 위한 첨단 기술로 운용되고 있으며, 중요 데이터에 대한 위성 통신 품질보증 기능을 제공한다. 본 논문에서는 위성망의 트래픽을 수집하고 데이터를 로깅하는 위성망 트래픽 수집 도구와 수집된 데이터를 마이닝을 통해 실시간 모니터링하고 통계 정보를 생성하는 위성망 패킷 데이터 분석 도구로 이루어진 위성망 패킷 데이터 분석 시스템에 대해 논한다. 위성망 패킷 데이터 분석 시스템은 데이터 송수신 정보를 모니터링 함으로써 실시간 위성 통신 상태를 점검하고, 전송 지연 및 실패 등의 위성 통신 오류 상태를 조기 진단하고 조치할 수 있는 위성망 품질 보증 서비스를 제공한다.

• The KIPS Transactions:PartD
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• v.18D no.6
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• pp.415-422
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• 2011

Finding similar strings is an important operation because textual data can have errors, duplications, and inconsistencies by nature. Many algorithms have been developed for string approximate searches and most of them make use of inverted lists to find similar strings. These algorithms basically perform merge operations on inverted lists. In this paper, we develop a bitmap representation of an inverted list and propose an efficient search algorithm that can skip unnecessary inverted lists without searching using bitmap filters. Experimental results show that the proposed technique consistently improve the performance of the search.

• Journal of KIISE:Computer Systems and Theory
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• v.35 no.7
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• pp.327-331
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• 2008

Optimal Extension Fields (OEFs) are finite fields of a special form which are very useful for software implementation of elliptic curve cryptosystems. Bailey and Paar introduced efficient OEF arithmetic algorithms including the $p^ith$ powering operation, and an efficient algorithm to construct OEFs for cryptographic use. In this paper, we give a counterexample where their $p^ith$ powering algorithm does not work, and show that their OEF construction algorithm is faulty, i.e., it may produce some non-OEFs as output. We present improved algorithms which correct these problems, and give improved statistics for the number of OEFs.

• International Journal of Highway Engineering
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• v.10 no.3
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• pp.79-86
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• 2008

This paper proposed the appropriate installation angle of skewed sensors for measuring vehicle wandering data, which are collected to figure out the location of dynamic weight of a moving vehicle on roadways. We developed a device using tape-switch sensors and a computer program and collected vehicle wandering data with the device and probe vehicles. As a result, the steeper the skewed sensor was installed, the lower the error was shown. However, we could not collect proper data when a skewed sensor was set up higher than $30^{\circ}$ due to tandem axle. Therefore, this study suggested the appropriate angle of skewed sensors as a degree of $20^{\circ}$ to $25^{\circ}$ for gathering wandering data.