• Communications for Statistical Applications and Methods
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• 제19권1호
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• pp.107-115
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• 2012

본 논문에서는 Yoo와 Cook (2007)에 의하여 제시된 다변량 회귀의 조건부 평균에 대한 최소 불일치 함수 접근법을 통한 최적 차원축소 부분공간의 추정에서 차원의 수가 추정된 선형결합들과 설명력 등에 어떤 영향을 미치는 지를 시뮬레이션 자료를 통하여 알아보았다. 그 결과 추정에 사용된 차원수에 따른 여러 결과들을 차원결정을 위한 검정과 함께 활용하면 모형에 필요한 차원수를 탐색하는데 매우 효과적임을 알 수 있었다.

• 한국건설관리학회:학술대회논문집
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• 한국건설관리학회 2003년도 학술대회지
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• pp.311-314
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• 2003

작업중단이 다음날의 현장 생산성에 미치는 영향을 정량화하기 위해 본 연구는 통계적 방법을 제안한다. 따라서 본 연구는 다음 영가설을 검정하는 절차를 거쳤다. '건설현장에서의 작업중단은 다음날의 현장 생산성과 생산성달성율에 아무런 영향을 미치지 않는다'. 이를 검정하기 위해 본 연구는 작업중단을 생산성에 영향을 미치는 더미 변수로 가정하고, 사례 데이터를 바탕으로 회귀분석을 실시, 작업중단이 생산성에 미치는 영향을 정량화하였다. 또한, 이론 바탕으로 작업중단이 다음날의 생산성달성율에 미치는 영향을 검토하였다. 이러한 연구를 바탕으로, 현장에서 작업연속성을 확보하기 위한 노력이 생산성 확보 차원에서 유효함을 알 수 있었다.

• Journal of the Korean Statistical Society
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• 제30권1호
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• pp.41-61
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• 2001

The minimum negative exponential disparity estimator(MNEDE), introduced by Lindsay(1994), is an excellenet competitor to the minimum Hellinger distance estimator(Beran 1977) as a robust and yet efficient alternative to the maximum likelihood estimator in parametric models. In this paper we define the negative exponential deviance test(NEDT) as an analog of the likelihood ratio test(LRT), and show that the NEDT is asymptotically equivalent to he LRT at the model and under a sequence of contiguous alternatives. We establish that the asymptotic strong breakdown point for a class of minimum disparity estimators, containing the MNEDE, is at least 1/2 in continuous models. This result leads us to anticipate robustness of the NEDT under data contamination, and we demonstrate it empirically. In fact, in the simulation settings considered here the empirical level of the NEDT show more stability than the Hellinger deviance test(Simpson 1989). The NEDT is illustrated through an example data set. We also define a goodness-of-fit statistic to assess adequacy of a specified parametric model, and establish its asymptotic normality under the null hypothesis.

• 한국안전학회지
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• 제32권4호
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• pp.107-113
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• 2017

This paper deals with the traffic factors related to the collisions of circular intersections. The purpose of this study is to develop traffic accident models by type of collision based on land use. In pursuing the above, the traffic accident data from 2010 to 2014 were collected from the "Traffic Accident Analysis System (TAAS)" data set of the Road Traffic Authority. A multiple regression model was utilized in this study to develop the traffic accident models by type of collision. 17 explanatory variables such as geometry and traffic volume factors were used. The main results are as follows. First, the null hypothesis that the type of land use does not affect the number of accidents by type of collision is rejected. Second, 10 accident models by type of collision based on land use are developed, which are all statistically significant. Finally, the ADT, inscribed circle diameter, bicycle lane, area of central island, number of speed hump, circulatory roadway width, splitter island, area of circulatory roadway, mean number of entry lane and mean width of entry lane are analyzed to see how they affect accident by type of accident based on land use.

• Applied Biological Chemistry
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• 제20권3호
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• pp.285-291
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• 1977

(가) 2개 이상(以上) t개의 시료(試料)를 3점기호척도시험법(點嗜好尺度試驗法)에 의해 실험한 결과를 통계처리(統計處理)하여 t개 시료 상호간(相互間)의 품질차(品質差)를 비교(比較)하는 해석법(解析法)에 대해서 검토(檢討) 하였다. (나) 그 결과 $Scheff{\acute{e}}'s$ method의 제1신법(第1新法)이 품질차(品質差)의 검출력(檢出力)에서나 얻어지는 정보량(情報量)에서 우수(優秀)함을 확인하고 t개의 시료에 대할 3점기호척도시험법(點嗜好尺度試驗法)의 해석방법(解析方法)으로써 실용성(實用性)이 있다는 결론을 얻었다. (다) 이때 correct oddity chosen에 대한 incorrec toddity chosen의 weight fraction은 chance probability에 의해 계산하여 1/2로 하였다.

• 한국통신학회논문지
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• 제30권9C호
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• pp.955-963
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• 2005

이 논문에서는 순차 방법을 쓰는 비동위상 부호획득 문제를 다루었다. 먼저, 비동위상 수신기 출력은 귀무가설 에서 거의 중심카이제곱 분포를 따름을 보이고, 이를 바탕으로 베셀함수를 어림하여 간단한 부호획득 기법을 얻는다. 이제까지의 부호획득 방법을 쓸 때와 간단하게 만든 부호획득 방법을 쓸 때의 성능을 덧셈꼴 흰빛 정규잡음 채널과 느리게 바뀌는 감쇄채널에서 견주어 보았다. 간단하게 만든 방법들은 이제까지의 방법들과 성능이 비슷하다는 것을 모의실험에서 알 수 있었다.

• 한국인지과학회:학술대회논문집
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• 한국인지과학회 2002년도 춘계학술대회
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• pp.111-116
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• 2002

The regularity effect for printed word recognition and naming depends on ambiguities between single letters (small grain-size) and their phonemic values. As a given word is repeated and becomes more familiar, letter-aggregate size (grain-size) is predicted to increase, thereby decreasing the ambiguity between spelling pattern and phonological representation and, therefore, decreasing the regularity effect. Lexical decision and naming tasks studied the effect of repetition on the regularity effect for words. The familiarity of a word from was manipulated by presenting low and high frequency words as well as by presenting half the stimuli in mixed upper- and lowercase letters (an unfamiliar form) and half in uniform case. In lexical decision, the regularity effect was initially strong for low frequency words but became null after two presentations; in naming it was also initially strong but was merely reduced (although still substantial) after three repetitions. Mixed case words were recognized and named more slowly and tended to show stronger regularity effects. The results were consistent with the primary hypothesis that familiar word forms are read faster because they are processed at a larger grain-size, which requires fewer operations to achieve lexical selection. Results are discussed in terms of a neurobiological model of word recognition based on brain imaging studies.

• Genomics & Informatics
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• 제5권2호
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• pp.61-67
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• 2007

The allele frequencies of markers as well as linkage disequilibrium (LD) can be changed in cases due to the LD between markers and the disease allele, exhibiting spurious associations of markers. To identify the true association, classical statistical tests for dealing with confounders have been applied to draw a conclusion as to whether the association of variants comes from LD with the known disease allele. However, a more direct test considering LD using estimated haplotype frequencies may be more efficient. The null hypothesis is that the different allele frequencies of a variant between cases and controls come solely from the increased disease allele frequency and the LD relationship with the disease allele. The haplotype frequencies of controls are estimated using the expectation maximization (EM) algorithm from the genotype data. The estimated frequencies are applied to calculate the expected haplotype frequencies in cases corresponding to the increase or decrease of the causative or protective alleles. The suggested method was applied to previously published data, and several APOE variants showed association with Alzheimer's disease independent from the APOE ${\varepsilon}4$ variant, rs429358, regardless of LD showing significant simulated p-values. The test results support the possibility that there may be more than one common disease variant in a locus.

• 대한교통학회지
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• 제27권1호
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• pp.107-114
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• 2009

보행은 인간의 기본적이면서 중요한 교통수단이다. 최근 들어 보행자 사고와 관련하여 보행안전이 중요시되고 있다. 이에 본 연구에서는 보행환경요소가 보행안전에 영향을 미치는지 살펴보았다. 선행연구에서 15개의 보행환경요소를 추출하여 설문조사를 실시하였고, 요인분석을 통해 4개의 요인을 추출하였다. 다중회귀분석 결과 F-value는 9.211, P-value는 0.000으로 귀무가설이 기각되어 보행환경요인은 보행안전에 영향력을 미치는 것으로 나타났다. 영향력은 보도특성, 경관성, 상업성, 보행특성의 순으로, 특히 경관성과 보도특성은 유의미한 것으로 분석되었다.

• 한국환경과학회지
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• 제24권4호
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• pp.393-401
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• 2015

Rainfall-runoff model of Jeju Oedo Stream was used to compute the optimal unit hydrograph by HEC-HMS model that reflecting on watershed characteristics. Each rainfall event was comparatively analyzed with the actual flow measurement using Clark, Snyder and SCS synthetic methods for derived unit hydrograph. Subsequently, the null hypothesis was established as p-value for peak flow and peak time of each unit hydrograph by one-way ANOVA(Analysis of variance) was larger than significance level of 0.05. There was no significant difference in peak flow and peak time between different methods of unit hydrograph. As a result of comparing error rate with actual flow measurement data, Clark synthetic unit graph best reflected in Oedo Stream as compared to other methods, and error rate of Clark unit hydrograph was 0.02~1.93% and error rate at peak time was 0~2.74%.