• 한국태양에너지학회 논문집
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• 제39권2호
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• pp.45-55
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• 2019

More than 76% of the detached houses in Korea are over 20 years old. These old detached houses have poor energy efficiency. According to the 2017 Housing Census (Statistics Korea), more than 50% of low-income families live in detached houses. Therefore, the improvement of energy efficiency in old detached houses is needed from the viewpoint of energy welfare. The general method of building energy modelling for the verification of energy efficiency is based on the construction year data of "Building Design Criteria for Energy Saving" due to the cost and time involved in collecting the thermal performance data of buildings. There is poor accuracy with the deterioration of long-term aging of building materials. Also, the selection of alternatives for energy performance improvement is based on the items to be applied, not a performance improvement goal. It is difficult to calculate energy performance that reflects variations in various parameters with dynamic energy simulations. In this study, the influence of long-term aging is used to accurately predict the energy performance of old detached houses. The building energy modelling method is called ENERGY#, which is a static analysis method based on ISO13790. Energy performance is evaluated by a combination of input variables including building orientation, insulation of walls and roof, thermal performance of windows and window/wall ratio, and infiltration rate. Finally, this study provides a way to determine alternatives that meet energy performance improvement goals.

• 대한산업공학회지
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• 제39권5호
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• pp.422-428
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• 2013

In many cases, an $\bar{X}$ control chart which is based on the performance variable is used in industrial fields. However, if the performance variable is too costly or impossible to measure and a less expensive surrogate variable is available, the process may be more efficiently controlled using surrogate variables. In this paper, we propose a model for the economic design of a VSI (Variable Sampling Interval) $\bar{X}$ control chart using a surrogate variable that is linearly correlated with the performance variable. The total average profit model is constructed, which involves the profit per cycle time, the cost of sampling and testing, the cost of detecting and eliminating an assignable cause, and the cost associated with production during out-of-control state. The VSI $\bar{X}$ control charts using surrogate variables are expected to be superior to the Shewhart FSI (Fixed Sampling Interval) $\bar{X}$ control charts using surrogate variables with respect to the expected profit per unit cycle time from economic viewpoint.

• 정보과학회 논문지
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• 제43권6호
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• pp.653-661
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• 2016

기존의 패턴기반 트리플 생성 시스템은 distant supervision의 가정으로 인해 오류 패턴을 생성하여 트리플 생성 시스템의 성능을 저하시키는 문제점이 있다. 이 문제점을 해결하기 위해 본 논문에서는 패턴과 프로퍼티 사이의 의미 유사도 기반의 패턴 신뢰도를 측정하여 오류 패턴을 제거하는 방법을 제안한다. 의미 유사도 측정은 비지도 학습 방법인 워드임베딩과 워드넷 기반의 어휘 의미 유사도 측정 방법을 결합하여 사용한다. 또한 한국어 패턴과 영어 프로퍼티 사이의 언어 및 어휘 불일치 문제를 해결하기 위해 정준 상관 분석과 사전 기반의 번역을 사용한다. 실험 결과에 따르면 제안한 의미 유사도 기반의 패턴 신뢰도 측정 방법이 기존의 방법보다 10% 높은 정확률의 트리플 집합을 생성하여, 트리플 생성 성능 향상을 증명하였다.

• Journal of the Korean Statistical Society
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• 제20권1호
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• pp.29-43
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• 1991

Two data-based bandwidth selectors which are optimal in the sense that they achieve n$\^$-$\frac{1}{2}$/ rate of convergence in kernel density estimation are proposed. The proposed bandwidth selectors are constructed by modifying Park and Marron's plug-in method. The first modification is taking Taylor expansion of the mean integrated squared error to two more terms than in the case of plug-in method. The second is estimating more accurately the functionals of the unknown density appeared in the minimizer of the expansion by using higher order kernels. The proposed bandwidth selectors were proved to be optimal in terms of convergence rate. According to small-sample Monte Carlo studies, the proposed bandwidth selectors showed better performance than all the other bandwidth selectors considered in the simulation.

• Journal of the Korean Statistical Society
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• 제29권3호
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• pp.351-360
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• 2000

This paper considers the problem of testing a variance change in infinite order autoregressive models. A cusum of squares test based on the residuals from an AR(q) model is constructed analogous to Inclan and Tiao (1994)'s test statistic, where q is a sequence of positive integers diverging to $\infty$. It is shown that under regularity conditions the limiting distribution of the test statistic is the sup of a standard Brownian bridge. Simulation results are given to illustrate the performance of the test.

• 응용통계연구
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• 제24권6호
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• pp.1021-1031
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• 2011

주가연계증권(ELS)은 주가와 연동되어 수익률이 결정되는 금융상품으로 현재 증권회사뿐만 아니라 은행에서도 많이 판매되고 있는 간접투자상품이다. 이 논문에서는 수익다이어그램을 통해 대표적인 주가연계증권의 수익구조를 알아보며 특히 현재 가장 많이 판매되고 있는 원금비보장 상품인 스텝다운형에 관심을 가진다. KOSPI 200과 홍콩 HSI를 기초자산으로 설정한 스텝다운형 상품에서 투자시점의 시계열 특성에 따른 조기상환여부와 경험적 분포를 이용한 VaR를 통한 위험률에 대해 고찰해 본다.

• Journal of the Korean Statistical Society
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• 제35권1호
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• pp.105-114
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• 2006

In this paper we propose a simple and computationally attractive difference-based variance estimator in nonparametric regression models with multivariate predictors. We show that the estimator achieves $n^{-1/2}$ rate of convergence for regression functions with only a first derivative when d, the dimension of the predictor, is less than or equal to 4. When d > 4, the rate turns out to be $n^{-4/(d+4)}$ under the first derivative condition for the regression functions. A numerical study suggests that the proposed estimator has a good finite sample performance.

• 응용통계연구
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• 제22권5호
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• pp.1007-1017
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• 2009

본 연구는 최근에 활발히 연구가 진행 중인 항공수요 예측 분야에서 사용되는 계절형 ARIMA 모형과 다변량 계절형 시계열 모형과의 성능을 비교한 것이다. 본 연구에서는 국제 여객 수요와 국제 화물 수요 예측을 위하여 실제 자료를 이용하여 비교한 결과 다변량 계절형 시계열 모형이 예측의 정확도 면에서 기존의 일변량 모형보다 우수함을 보였다.

• 응용통계연구
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• 제18권3호
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• pp.543-553
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• 2005

선형 로지스틱 모형은 신용위험 관리를 위한 신용평점 모형 구축에 있어서 널리 쓰이고 있는 방법론이다. 본 논문에서는 신용평점화를 위하여 로지스틱 회귀 방법에 기초한 스플라인 방법론을 다루고자 한다. 선형 스플라인과 자동적인 변수선택 방법을 채택하였다. 모의 실험을 통하여 스플라인 방법의 성능을 규명하였다.

• 대한원격탐사학회지
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• 제31권1호
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• pp.21-28
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• 2015

The essential idea of de-noising is referring to neighboring pixels of a center pixel to be updated. Conventional adaptive de-noising filters use local statistics, i.e., mean and variance, of neighboring pixels including the center pixel. The drawback of adaptive de-noising filters is that their performance becomes low when edges are contained in neighboring pixels, while anisotropic diffusion de-noising filters remove adaptively noises and preserve edges considering intensity difference between neighboring pixel and the center pixel. The anisotropic diffusion de-noising filters, however, use only intensity difference between neighboring pixels and the center pixel, i.e., local statistics of neighboring pixels and the center pixel are not considered. We propose a new connectivity function of two adjacent pixels using statistics of neighboring pixels and apply connectivity function to diffusion coefficient. Experimental results using an aerial image corrupted by uniform and Gaussian noises showed that the proposed algorithm removed more efficiently noises than conventional diffusion filter and median filter.