• 한국정보통신학회논문지
• /
• 제10권12호
• /
• pp.2132-2139
• /
• 2006

내포 병렬성을 포함하는 병렬 프로그램은 복잡한 수행 양상을 가지며, 태스크들은 병행적으로 수행되는 경향이 있다. 이러한 병행성은 대부분의 오류을 유발하는 근본적인 원인이 된다. 본 논문은 병렬 프로그램 수행양상을 영상화하여 두 태스크간의 병행성을 판별할 수 있는 새로운 방법을 제안한다. 기존의 방법들은 전역적인 구조를 보이는데 제약이 있고 과다한 추상화로 인하여 수행양상의 직관성을 저해하는 경향이 있다. 본 논문에서 제안한 기법은 영상 가시화에 적합한 레이블링 기법을 제안하고, 제안한 레이블링 기법을 적용하여 산출된 각 태스크의 레이블정보를 2차원 평면상에서 분할된 영역으로 표현한다. 이를 토대로 각 태스크의 순서화 관계를 식별할 수 있는 독립된 영상을 생성한다. 결과로 생성된 영상은 관련 태스크의 의미론적 분석을 간소화하고 전체 프로그램의 전역적 수행 구조의 개요를 사용자에게 효과적으로 제공한다.

• Journal of Ecology and Environment
• /
• 제31권4호
• /
• pp.333-339
• /
• 2008

We investigated death rates, growth rates and recruitment of culms in two neighboring bamboo (Phyllostachys bamboosoides) stands nested in by two different bird species to analyze stand structure and to design conservation strategies. A third bamboo grove not used by birds, the Taewha stand, was included as a control stand. The bamboo stand occupied by birds in the family Ardeidae (the Ardeidae stand) had an approximately 1.5 times higher culm density than the stand occupied by birds in the family Corvidae (the Corvidae stand). The crude death rate and the number of newly emerged shoots were also higher in the Ardeidae stand than the Corvidae stand. The death rate for bamboo in the Ardeidae stand was not dependent on diameter at breast height (DBH) and was almost 40% for culms of all sizes, whereas most dead culms in the Corvidae stand were < 4 cm DBH. Consequently, we conclude that in the Ardeidae stand, density-independent causes of death are operating, while density-dependent factor are more important in the Corvidae site. The results of soil analysis in these stands suggest that the density-independent death pattern observed in the Ardeidae stand may be due to soil acidification resulting from wastes produced by the birds during breeding. On the other hand, the culm distribution and death patterns in the Corvidae stand suggest that the stand characteristics were not affected by the nesting birds. These results suggest that different conservation strategies must be applied to conserve bamboo groves used by ardeids and corvids for nesting.

• 대한토목학회논문집
• /
• 제31권3D호
• /
• pp.469-476
• /
• 2011

본 연구는 다층모형(multilevel model)을 상수원관리지역 주민지원사업 정책평가에 활용하는데 있어 유효성 및 효과를 이해하는데 연구의 목적이 있다. 정책의 대상이 위계적인(hierarchical) 특성을 지니고 있는 경우 다층모형을 이용하여 정책평가를 하는 것이 정책의 효과를 평가하고 검증하는데 있어 적절하다. 또한 이 모형은 기존 평가결과의 재평가 등에 응용될 수 있다. 상수원관리지역의 주민지원사업을 대상으로 주민만족도와 경제적 도움정도를 정책효과변수로 하여 다층모형을 적용 하였다. 그 결과 정책효과변수에 기존 평가결과 및 중요한 사업으로 여겨지던 소득증대사업 등이 직접적인 영향을 미치지 못함을 통계적으로 확인할 수 있었다. 본 연구는 다음과 같은 세 가지의 정책적 함의를 지닌다. 첫째, 정책 및 사업평가에 있어 정책의 효과를 엄밀히 파악하기 위하여 위계적 구조를 고려할 수 있는 다층모형을 이용하여야 한다. 둘째, 기관평가의 순위 도출에 있어 다층모형을 이용하여 지표에 의한 성과지표와 보완적으로 이용해야 한다. 셋째, 위계적 구조의 하나로서 공간적 위계를 고려하여 정책평가를 시행하여야 한다.

• 컴퓨터교육학회논문지
• /
• 제8권1호
• /
• pp.93-103
• /
• 2005

대부분의 프로그램 실행 시간은 루프 구조에서 소비되기 때문에 순차 루프 프로그램으로부터 병렬성을 추출하는 것은 프로그램을 빠르게 실행하는 데 필수적이다. 병렬성을 추출하기 위한 기존의 연구들은 주로 불변 자료 종속 거리에 초점을 맞추어왔다. 본 논문에서는 중첩 루프에서 자료 종속성을 제거하는 방법과 자료 종속성 제거 방법을 확장한 프로시저 호출을 가진 루프에서 병렬성을 추출하는 방법을 제안한다. 이 두 가지 방법들은 모두 자료 종속 거리에 관계없이 적용할 수 있다. 중첩 루프에서의 자료 종속성 제거 방법과 프로시저 호출을 가진 루프에서 병렬성을 추출하는 방법을 기존의 방법들과 CRAY-T3E에서 성능 평가를 하였다. 두 개의 방법 모두가 기존의 방법들보다 매우 우수함을 보였다.

• 대한전자공학회:학술대회논문집
• /
• 대한전자공학회 2002년도 ITC-CSCC -1
• /
• pp.301-304
• /
• 2002

Recently, database technologies have been used commonly. But, ordinary technologies aren't suitable to construct a complicated database such as a classical literature database or an archaeological relic's database. Because this kinds of data are semi-structured data that doesn't have regular structures, database schema can't be defined before databases. We have proposed DREAM model for semi-structured databases. In this model, a database consists of five elements and the model has operations similar to operation of set theory. And further we have introduced dynamic schema "shape" showing structure of each element. We have already realized a prototype of DBMS adopting DREAM model (DREAM DBMS) and constructing function of shapes. However, shape is imperfect to describe database structures because it can't explain nested structures of elements. In this paper, we will profuse a "shape graph"that is dynamic schema showing database structures more exactly and extend the DREAM DBMS. Further we will evaluate the performance of constructing function of shapes and shape graphs.

• BMB Reports
• /
• 제40권2호
• /
• pp.172-179
• /
• 2007

PCR-mediated recombination describes the process of in vitro chimera formation from related template sequences present in a single PCR amplification. The high levels of genetic redundancy in eukaryotic genomes should make recombination artifacts occur readily. However, few evolutionary biologists adequately consider this phenomenon when studying gene lineages. The cytosolic glyceraldehyde-3-phosphate dehydrogenase gene (GapC), which encodes a NADP-dependent nonphosphorylating glyceraldehyde-3-phosphate dehydrogenase in the cytosol, is a classical lowcopy nuclear gene marker and is commonly used in molecular evolutionary studies. Here, we report on the occurrence of PCR-mediated recombination in the GapC gene family of Hibiscus tiliaceus. The study suggests that recombinant areas appear to be correlated with DNA template secondary structures. Our observations highlight that recombination artifacts should be considered when studying specific and allelic phylogenies. The authors suggest that nested PCR be used to suppress PCRmediated recombination.

• 응용통계연구
• /
• 제19권2호
• /
• pp.349-360
• /
• 2006

SAS의 PROC MIXED를 사용하면 일반적인 ANOVA 추정량뿐만 아니라 더 많은 장점을 갖는 제한최대우도추정법 또는 최대우도추정법으로 모수들을 추론할 수 있다. 혼합모형에 속하는 불균형중첩오차구조를 갖는 선형회귀모형에서 랜덤효과와 관련된 그룹간 분산의 신뢰 구간과 고정효과에 해당되는 회귀 계수들에 대 한 신뢰구간을 구하기 위하여 세 가지 크기를 갖는 표본에 대하여 PROC MIXED를 사용하였다. 모의실험을 실행한 결과, 대표본인 경우에는 모수들의 신뢰 구간을 구하기 위하여 PROC MIXED를 활용할 수 있지만, 소표본인 경우에는 PROC MIXED를 사용할 경우, 그룹간 분산의 신뢰 구간과 회귀계수 가운데 절편항의 신뢰구간은 주어진 신뢰계수를 지키지 못하는 것을 보인다.

• Communications for Statistical Applications and Methods
• /
• 제25권2호
• /
• pp.173-184
• /
• 2018

In medical or public health research, it is common to encounter clustered or longitudinal count data that exhibit excess zeros. For example, health care utilization data often have a multi-modal distribution with excess zeroes as well as a multilevel structure where patients are nested within physicians and hospitals. To analyze this type of data, zero-inflated count models with mixed effects have been developed where a count response variable is assumed to be distributed as a mixture of a Poisson or negative binomial and a distribution with a point mass of zeros that include random effects. However, no study has considered a situation where data are also censored due to the finite nature of the observation period or follow-up. In this paper, we present a weighted version of zero-inflated Poisson model with random effects accounting for variable individual follow-up times. We suggested two different types of weight function. The performance of the proposed model is evaluated and compared to a standard zero-inflated mixed model through simulation studies. This approach is then applied to Medicaid data analysis.

• 대한교통학회지
• /
• 제7권1호
• /
• pp.19-34
• /
• 1989

In general, Shopping centers are located in the center of transportation, which induce more traffic concentration than other facilities. As a result, it becomes to one of the aggravating factors of urban ＆ transportation problem such as traffic conjestion, parking problems. Thus, in planning shopping-center, it is desirable that consumer\`s trip pattern is should lie more carefully analyzed in order to alleviate the above problems. This study is aimed at finding the characteristics of shopping tripes and analyzing the choice behavior of shopping center and mode-to-shop. This study has developed a nested logit model in which consumers choose shopping center and mode-to-shop with a sequential structure. The model was estimated using household data from the 1989 May, Seoul metropolitan area and the 18 alternatives of shopping center and 5 mode alternatives. The estimated model have been evaluated and it may be concluded that this model for shopping trips is effective and fesible. The conclusion of this study are as fellows. 1. Out-of-vehicle travel time is more important factor affecting behavior of mode choice than in-vehicle travel time. 2. All of direct-elasticities for mode with respect to the travel time is more elastic than travel cost. 3. Accessibility to shop is more important factor affecting the choice of shopping center than parking space. 4. The value of out-of-vehicle travel time exceeds the value of in-vesicle travel time by 1.64 times.

• 아동학회지
• /
• 제37권6호
• /
• pp.107-117
• /
• 2016

Objective: This study examined the construct validity of K-WPPSI-IV. Factor structures of the structures of the K-WPPSI-IV full scale as well as primary index scales for two age ranges (2 years, 6 months to 3 years, 11 months; 4 years to 7 years, 7 months) were examined. Methods: Data were collected from 1,700 children aged 2 years, 6 months to 7 years, 7 months during the K-WPPSI-IV standardization. Confirmatory factor analyses were conducted using the K-WPPSI-IV subtest performances with maximum likelihood estimation using Amos 18. Results: First, the three-factor model (verbal comprehension, visual spatial, and working memory) fitted best for the younger age range. However, the five-factor model (verbal comprehension, visual spatial, fluid reasoning, working memory, and processing speed) fitted best for the older age range. Residuals suggest the presence of two nested subfactors within the verbal comprehension factor (broad/expressive and focused/simple). Second, the confirmatory factor analysis on primary index subtests identified factors that account for the intercorrelations among the reduced sets of primary index subtests. Conclusion: The findings showed that the theoretical structures of WPPSI-IV subtests were confirmed within K-WPPSI-IV.