• Journal of the Ergonomics Society of Korea
• /
• v.10 no.1
• /
• pp.11-22
• /
• 1991

This paper aims to examine experimentally the difference of subjectively measured degree of depth between two dimensional (2D) and three dimensional (3D) images. For this paper, two experiments were conducted; in the first experiment, the subjects were asked to estimate the distance between two objects presented with different depths, while in the second experiment, the subjects' role was to rank three objects in the order of distance from the screen. In both experiments, the objects were presented either in 2D or 3D images. The results of the experiments show that the use of 3D images can induce more accurate and more stable estimates of distance than the use of 2D images. However, it is also noted that the absolute degree of depth is not the unique criteria utilized by the subjects for the distinction of small differences of depth.

• Proceedings of the KIEE Conference
• /
• 1999.07g
• /
• pp.3048-3050
• /
• 1999

This paper suggests a position estimating algorithm using mono vision system with projective geometry method. Generally, 3-D information can not be easily extracted from mono vision system which is taken by a camera at a specific point. But this defect is overcome by adopting model-based image analysis and selecting lines and points on the ground as natural landmarks. And this paper suggests a method that estimates position from many natural landmarks by distance error weight function.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2013.10a
• /
• pp.346-353
• /
• 2013

Industrial processes need to be monitored in real-time based on the input-output data observed during their operation. Abnormalities in an induction motor should be detected early in order to avoid costly breakdowns. To early identify induction motor faults, this paper effectively estimates spectral envelopes of each induction motor fault by utilizing a linear prediction coding (LPC) analysis technique and an expectation maximization (EM) algorithm. Moreover, this paper classifies induction motor faults into their corresponding categories by calculating Mahalanobis distance using the estimated spectral envelopes and finding the minimum distance. Experimental results shows that the proposed approach yields higher classification accuracies than the state-of-the-art approach for both noiseless and noisy environments for identifying the induction motor faults.

• Journal of the Korean housing association
• /
• v.22 no.5
• /
• pp.47-57
• /
• 2011

The purpose of this research is to demonstrate the necessity of conserving and maintaining eco-parks by estimating their economic value. Wonheung-ee Park in Sannam 3 District of Cheongju City was chosen as the subject and a quantitative estimation was conducted. The quantitative analysis utilized the hedonic price model that estimates the value of non-market goods. The summarized results of this study are follows. The subject park influenced the prices of its neighboring apartments. The most important factor was the distance between the park and the subject apartment. When the distance was longer than 400m, the impact was greatest. The quantitative assessment also showed that apartment prices and the distance between an apartment and the park had a negative relationship. When the distance increased by 1%, apartment prices decreased by 0.430%. This means that within a certain distance, the closer an apartment is to the park, the higher is the price. Demonstrating the economic value of eco-parks, this study also supports the importance of preserving eco-areas. It generally shows that when we develop a city, we should refrain destroying the ecosystem.

• Communications for Statistical Applications and Methods
• /
• v.5 no.2
• /
• pp.517-529
• /
• 1998

When the sample size is small the robust minimum Hellinger distance (HD) estimator can have substantially poor relative efficiency at the true model. Similarly, approximating the exact null distributions of the ordinary Hellinger distance tests with the limiting chi-square distributions can be quite inappropriate in small samples. To overcome these problems Harris and Basu (1994) and Basu et at. (1996) recommended using a modified HD called penalized Hellinger distance (PHD). Lindsay (1994) and Basu et al. (1997) showed that another density based distance, namely the negative exponential disparity (NED), is a major competitor to the Hellinger distance in producing an asymptotically fully efficient and robust estimator. In this paper we investigate the small sample performance of the estimates and tests based on the NED and penalized NED (PNED). Our results indicate that, in the settings considered here, the NED, unlike the HD, produces estimators that perform very well in small samples and penalizing the NED does not help. However, in testing of hypotheses, the deviance test based on a PNED appears to achieve the best small-sample level compared to tests based on the NED, HD and PHD.

• The Bulletin of The Korean Astronomical Society
• /
• v.37 no.2
• /
• pp.75.2-75.2
• /
• 2012

SNe Ia are a well-known powerful distance indicator. Type Ia supernova (SN) 2011fe was discovered in the nearby spiral galaxy M101 in 2011. It was discovered in less than one day after its explosion and is one of the nearest SNe Ia. Therefore SN 2011fe plays a significant role for calibrating the luminosity of the SNe Ia as well as for studying the progenitors of SNe Ia. However, previous estimates of the distance to M101 based on various methods show a large range. We present a new determination of the distance to M101 using the tip of the red giant branch (TRGB) method. We measure the distance from the F555W and F814W images of nine fields taken with the HST/ACS and HST/WFPC2 available in the HST archive. We derive a distance estimate with much smaller errors than previous studies. We discuss the implication of our results in relation with the calibration of optical and near-infrared maximum magnitudes of SNe Ia and the Hubble Constant.

• Journal of the Institute of Electronics Engineers of Korea SC
• /
• v.48 no.3
• /
• pp.21-29
• /
• 2011

This paper presents a method that estimates distance and velocity of an object with reliability regardless of maneuver status of the target in stereo vision system. A stereo vision system can calculate a distance with disparity from left and right images. However, the distance estimation error may occur due to quantization error of image pixel. A sub-pixel interpolation method minimizes the quantization error and estimates accurate disparity with real value. Extended Kalman filter (EKF) was used to minimize the error covariance and estimate the object's velocity. However, divergence problem occurs due to model uncertainty when a target maneuvers highly, which makes the estimation error increase. In this paper, we propose a virtual model extended Kalman filter (VMEKF) method that minimizes the processing time and provides reliable estimation ability regardless of maneuver status. Computer simulations and experimental results in real road environments demonstrate that the proposed method gives a reliable estimation performance and reduces processing time under various maneuver status while comparing other estimation filters.

• Journal of the Korean earth science society
• /
• v.31 no.7
• /
• pp.827-838
• /
• 2010

The purpose of this study is to identify the conceptions of elementary school teachers regarding the variation scale about astronomical distance and its accuracy with distance increased. The astronomical distance questionnaire was administered to 69 elementary school teachers, then; three teachers were selected to interview about their conceptions. Results showed that many elementary school teachers overestimated the distance from the Earth to the Moon and to the Sun, and dramatically underestimated the distances to the nearest star and to the nearest galaxy. They inferred astronomical distance with the use of both intuitive (psychological) measure and theoretical (calculative) measure. They well recited the terminology such as AU and a light-year, yet they did not show a good understanding of what the terms exactly means. Some teachers thought that the distance to Neptune is farther than the distance from Earth to the nearest star. There was a considerable variability in the participants' estimates of astronomical distances. Elementary school teachers showed a tendency to overestimate the distance as it gradually increases to the outer solar system.

• Communications for Statistical Applications and Methods
• /
• v.21 no.3
• /
• pp.213-224
• /
• 2014

In this paper, we study the problem of transforming to normality. We propose to estimate the transformation parameter by minimizing a weighted squared distance between the empirical characteristic function of transformed data and the characteristic function of the normal distribution. Our approach also allows for other symmetric target characteristic functions. Asymptotics are established for a random sample selected from an unknown distribution. The proofs show that the weight function $t^{-2}$ needs to be modified to have thinner tails. We also propose the method to compute the influence function for M-equation taking the form of U-statistics. The influence function calculations and a small Monte Carlo simulation show that our estimates are less sensitive to a few outliers than the maximum likelihood estimates.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2007.05a
• /
• pp.1081-1083
• /
• 2007

The study in river basin has been performed for the identify water quality impaired stream segments, to create a priority ranking of those segments, and to calculate the heavy metal ion distribution for each impaired segment based on chemical and physical water quality standards. Two methods for modeling the potential area-specific heavy metal distribution are pursued in this study. First, a novel approach focuses on distance. Heavy metal distribution can be associated with a particular small geographic area. Based on the derived estimates an distribution map can be generated. Second, the approach is used the near watershed by means of kriging interpolation algorithm. These approaches provide an alternative distribution mapping of the area. The exposure estimates from both of these modeling methods are then compared with other environmental monitoring data. A GIS-based model will be used to mimic the hierarchical stream structure and processes found in natural watershed. Specifically, the relationship between landscape variables and reach scale habitat conditions most influential found in the Abandoned mine will be explored.