• 충청수학회지
• /
• 제22권2호
• /
• pp.171-175
• /
• 2009

Let $A_1,\;A_2,\;{\cdots},\;A_n$ be a sequence of events on a given probability space. Let $m_n$ be the number of those $A_{i}{^{\prime}}s$ which occur. We establish an improved lower bounds of Univariate Bonferroni-Type inequality by using the linearity of binomial moments $S_1,\;S_2,\;S_3,\;S_4$ and$S_5$.

• 벤처창업연구
• /
• 제6권3호
• /
• pp.85-107
• /
• 2011

본 연구는 중소기업진흥공단으로부터 중소 벤처기업 정책자금 지원을 받은 중소 벤처기업의 수익성, 안정성, 활동성, 성장성 등 재무성과를 회귀분석 하였다. 1998년부터 2009년까지 중복 지원이 아닌 오직 1회에 한하여 지원받은 기업만을 대상으로 중소 벤처기업 정책자금을 지원받기 직전년도말 재무성과와 중소 벤처기업 정책자금을 지원받은 4년차 말 이후 재무성과를 회귀분석 하였다. 연구표본은 재무제표를 연속보유한 489개 업체 2,417개 재무제표이며, 재무성과 누계평균을 가지고 정책자금 효과와 그 인과관계를 분석하였다. 연구결과는 다음과 같다. 첫째, 정책자금을 지원받기 직전년도 말보다 정책자금을 지원 받은 4년차 말 이후 수익성, 안정성, 활동성, 성장성이 유의한 양(+)의 영향을 보여주고 있음을 발견하였다. 이는 정책자금 지원이 긍정적 재무성과를 가져오고 있음을 시사한다. 둘째, 성장성 지표인 총자산증가율은 매출액영업이익률에, 안정성 지표인 이자보상 비율은 총자산순이익률에 유의한 양(+)의 영향을 미치고 있음을 발견하였다. 이는 성장성 지표와 안정성 지표가 수익성에 영향을 미치므로 정책자금 지원이 이자를 보상할 여력을 증대시키는 등 재무건전성에 긍정적 영향을 미치고 있음을 시사한다. 셋째, 정책자금 지원방식, 정책자금 지원내용, 정책자금 지원규모, 업력, 종업원 수 등이 재무성과에 미치는 영향은 재무성과가 보여주는 종속변수에 따라 유의하게 나타나거나 유의하지 않게 나타났다. 이는 종속변수에 따라 유의성의 차이가 있음을 의미하며, 유의하지 않더라도 양(+)의 영향을 미친다는 일관성을 보여주고 있다.

• 동아시아식생활학회지
• /
• 제17권5호
• /
• pp.727-737
• /
• 2007

The aims of this study was to suggest a new efficiency measurement indicator for evaluating the management efficiency of decision making units(DMUs) in the contract foodservice industry. The data envelopment analysis(DEA) model which considers multiple inputs and outputs and looking for benchmarks, was used to compare the productivity of DMUs. We considered sales, profits, and customer satisfaction as output variables and it adopted food cost, labor cost and administrative expense as input variables. The results of applying DEA revealed relatively efficient types of business and service types. The efficiency of school units was highest and the mired service type was the most efficient one. In this study the CCR model efficiency was analysed with profit and the customer satisfaction index by the matrix method. DEA efficiency was correlated with profit but there was no correlation between DEA efficiency and the customer satisfaction index.

• 아태비즈니스연구
• /
• 제2권2호
• /
• pp.1-35
• /
• 2011

Facing information overload in today's complex environments, managers look to a concise set of marketing metrics to provide direction for marketing decision making. While there have been several papers dealing with the theoretical aspects of dashboard creation, no research creates and tests a dashboard using scientific techniques. This study develops and demonstrates an empirical approach to dashboard metric selection. In a fast moving consumer goods category, this research selects leading indicators for national-brand and store-brand sales and revenue premium performance from 99 brand-specific and relative-to-competition variables including price, brand equity, usage occasions, and multiple measures of awareness, trial/usage, purchase intent, and liking/satisfaction. Plotting impact size and wear-in time reveals that different kinds of variables predict sales at distinct lead times, which implies that managerial action may be taken to turn the metrics around before performance itself declines.

• Journal of the Korean Statistical Society
• /
• 제27권1호
• /
• pp.67-90
• /
• 1998

In this paper we analytically study model misspecification that arises in regression analysis of nonstationary seasonal time series. We assume the underlying data generating process is a seasonally or a regularly and seasonally integrated process. We first study consequences of totally misspecified cases where seasonal indicator variables, a linear time trend, or another statistically independent seasonally integrated process are used as predictor variables in order to model the nonstationary seasonal behavior of the dependent variable. Then we study consequences of partially misspecified cases where the dependent variable and a predictor variable are cointegrated at some, but not all of the frequencies corresponding to the nonstationary roots.

• 대한기계학회논문집
• /
• 제19권9호
• /
• pp.2237-2248
• /
• 1995

In incompressible flow which has multi-length scale, it has a very important effect which dependent variables are used for adaptive grid generation. Among many length scales in incompressible flow, the dependent variables used for the adaptive grid generation should be able to represent the feature of the concerned system. In this paper, by using vorticity and stream function, in addition to velocity components, the smoother and more stable grid generation is possible and these four flow properties represent each scale. The adaptive grid generation for a lid-driven cavity flow with $N_{re}$ =3200 using four flow properties such as velocity components, vorticity, stream function is performed, and the usefulness of using vorticity and stream function as the indicator for adaptive grid generation is shown.

• 영어어문교육
• /
• 제11권2호
• /
• pp.1-18
• /
• 2005

This study is a preliminary investigation of the nature of discourse marker acquisition in Korean American speakers of English. Discourse markers are of interest because they are not an aspect of language taught through formal instruction either to native or non-native speakers. Therefore, discourse marker use serves as indirect evidence of face-to-face interaction with native speakers and an indicator of integration. In this light, the present study examines the presence of discourse markers in Korean Americans. The markers chosen for analysis were you know, like, and I mean. The data consist of spontaneous speech elicited from interviews. Sociolinguistic variables such as age, sex, and generation (i.e., $1^{st}$, 1.5, $2^{nd}$) were examined. Results show that there appears to be interaction between the variables and discourse marker use. While all speakers showed variable acquisition of markers, younger, female, and 1.5 generation speakers were found to use discourse markers more than other speakers. Although discourse marker use is optional and thus not a linguistic feature that must be necessarily acquired, it is clear that use is pervasive and acquired differentially by English speakers irrespective of whether they are native or not.

• Journal of Information Processing Systems
• /
• 제14권4호
• /
• pp.904-915
• /
• 2018

We demonstrate how social media content can be used to predict the unemployment rate, a real-world indicator. We present a novel method for predicting the unemployment rate using social media analysis based on natural language processing and statistical modeling. The system collects social media contents including news articles, blogs, and tweets written in Korean, and then extracts data for modeling using part-of-speech tagging and sentiment analysis techniques. The autoregressive integrated moving average with exogenous variables (ARIMAX) and autoregressive with exogenous variables (ARX) models for unemployment rate prediction are fit using the analyzed data. The proposed method quantifies the social moods expressed in social media contents, whereas the existing methods simply present social tendencies. Our model derived a 27.9% improvement in error reduction compared to a Google Index-based model in the mean absolute percentage error metric.

• 대한임베디드공학회논문지
• /
• 제17권4호
• /
• pp.249-255
• /
• 2022

The COVID-19 virus appeared in 2019 and is extremely contagious. Because it is very infectious and has a huge impact on people's mobility. In this paper, multiple linear regression and random forest models are used to predict the number of COVID-19 cases using COVID-19 infection status data (open source data provided by the Ministry of health and welfare) and Google Mobility Data, which can check the liquidity of various categories. The data has been divided into two sets. The first dataset is COVID-19 infection status data and all six variables of Google Mobility Data. The second dataset is COVID-19 infection status data and only two variables of Google Mobility Data: (1) Retail stores and leisure facilities (2) Grocery stores and pharmacies. The models' performance has been compared using the mean absolute error indicator. We also a correlation analysis of the random forest model and the multiple linear regression model.

• 한국환경복원기술학회지
• /
• 제23권4호
• /
• pp.85-96
• /
• 2020

The honeybee serves for most entomophilous flowers. They are a core species for maintaining the ecological system. Though the urban ecological system needs bees' mediation of pollination as well, we have little understanding on how the honeybee reacts to the physical environments of an urban city. This study is a basic research to enhance the potential environment for pollination in an urban area and aims to review the urban environmental variables which are highly linked to the pollination mediations by the honeybee. The study composed a Maxent model by adopting nine urban environmental variables and the locations of the Apis mellifera's appearances around 52 spots in Seoul. The variables reflect the ecology of the Apis mellifera. Of the urban environmental variables used for the model composition, six variables were found as not having meaningful correlations with the Apis mellifera's appearances and finally, building coverage, actual vegetation and land cover were selected as the appearance variables of the Apis mellifera. The AUC, the reliability indicator of the final model was 0.791 (sd=0.077). And the importance data of the variables used for the model were 55.6%, 27.9%, and 16.5% for building coverage, actual vegetation and land cover, respectively. The result of the study showed that the building coverage has the highest correlation with the appearance of the honeybee. And, as per the actual vegetation, the artificially tree planted area as well as the cultivated field and meadow in an urban area were functioning as the most important environmental conditions for the honeybee to be inhabitable. The study is expected to be utilized as the base material for the urban planning and park green area planning to enhance the potential environment for pollination in an urban area.