• Journal of information and communication convergence engineering
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• v.8 no.5
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• pp.575-580
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• 2010

Eye gaze as a form of input was primarily developed for users who are unable to use usual interaction devices such as keyboard and the mouse; however, with the increasing accuracy in eye gaze detection with decreasing cost of development, it tends to be a practical interaction method for able-bodied users in soon future as well. This paper explores a low-cost, robust, rotation and illumination independent eye gaze system for gaze enhanced user interfaces. We introduce two brand-new algorithms for fast and sub-pixel precise pupil center detection and 2D Eye Gaze estimation by means of deformable template matching methodology. In this paper, we propose a new algorithm based on the deformable angular integral search algorithm based on minimum intensity value to localize eyeball (iris outer boundary) in gray scale eye region images. Basically, it finds the center of the pupil in order to use it in our second proposed algorithm which is about 2D eye gaze tracking. First, we detect the eye regions by means of Intel OpenCV AdaBoost Haar cascade classifiers and assign the approximate size of eyeball depending on the eye region size. Secondly, using DAISMI (Deformable Angular Integral Search by Minimum Intensity) algorithm, pupil center is detected. Then, by using the percentage of black pixels over eyeball circle area, we convert the image into binary (Black and white color) for being used in the next part: DTBGE (Deformable Template based 2D Gaze Estimation) algorithm. Finally, using DTBGE algorithm, initial pupil center coordinates are assigned and DTBGE creates new pupil center coordinates and estimates the final gaze directions and eyeball size. We have performed extensive experiments and achieved very encouraging results. Finally, we discuss the effectiveness of the proposed method through several experimental results.

• The Korean Journal of Applied Statistics
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• v.14 no.1
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• pp.13-24
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• 2001

In this paper, we investigated mean estimation methods in two-phase sampling. Under the fixed expected cost we reviewed the optimal sample sizes, minimum variances and approximate unbiased variance estimators for usual ratio estimator, stratified sample mean with proportional allocation and Rao's allocation of the second phase sample. Also we proposed combined ratio estimator, which uses both ratio estimation and stratification and derived optimal sample size, minimum variance and unbiased variance estimator. Through a limited simulation study, we compared estimators by design effects and came to know that ratio estimator is more efficient than stratified sample mean in some cases and inefficient in the other cases, but combined ratio estimator is more efficient than others in most cases.

• Journal of KIISE:Information Networking
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• v.37 no.6
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• pp.431-443
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• 2010

In this paper, we propose a range-free localization method that can improve the estimation accuracy of Approximate Point in Triangle(APIT), which is the representative localization method for low cost wireless sensor networks. Specifically, we propose extended-APIT(e-APIT) method, which minimizes the error in deciding whether an object is in an area formed by three beacons. We also propose a way to improve the localization by narrowing down the potential localization area using the signals from neighboring beacons. According to the simulation performed, the proposed e-APIT method demonstrated noticeable accuracy improvement over the conventional APIT method.

• The Korean Journal of Applied Statistics
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• v.37 no.1
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• pp.103-118
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• 2024

The horseshoe prior is notably one of the most popular priors in sparse regression models, where only a small fraction of coefficients are nonzero. The parameter space of the horseshoe prior is much smaller than that of the spike and slab prior, so it enables us to efficiently explore the parameter space even in high-dimensions. However, on the other hand, the horseshoe prior has a high computational cost for each iteration in the Gibbs sampler. To overcome this issue, various MCMC algorithms for the horseshoe prior have been proposed to reduce the computational burden. Especially, Johndrow et al. (2020) recently proposes an approximate algorithm that can significantly improve the mixing and speed of the MCMC algorithm. In this paper, we compare (1) the traditional MCMC algorithm, (2) the approximate MCMC algorithm proposed by Johndrow et al. (2020) and (3) its variant in terms of computing times, estimation and variable selection performance. For the variable selection, we adopt the sequential clustering-based method suggested by Li and Pati (2017). Practical performances of the MCMC methods are demonstrated via numerical studies.

• 제어로봇시스템학회:학술대회논문집
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• 1987.10a
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• pp.791-796
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• 1987

In this paper, an efficient algorithm to estimate the volume and surface area from ultrasonic imaging and a reconstruction algorithm to generate three-dimensional graphics are presented. The computing efficiency is Improved by using the graph theory and the algorithm to determine proper contour points is performed by applying several tolerances. The search for contour points is limited by the change in curvature in order to provide an efficient search of the minimum cost path. These algorithms are applied to a selected mathematical model of ellipsoid. The results show that the measured value of the volume and surface area for the tolerances of 1.0005, 1.001 and 1.002 approximate to the measured values for the tolerance of 1.000 resulting in small errors. The reconstructed 3-dimensional Images are sparse and consist of larger triangular tiles between two cross sections as tolerance is increased.

• Journal of Korean Society for Atmospheric Environment
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• v.17 no.E4
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• pp.163-168
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• 2001

Estimating the emission rate of VOCs from a gasoline industry at national level can be a challenging take even though the estimation is mean-based. However, using the procedures in the US EPA AP-42 guidelines, it is possible to approximate the mean industry emission rate once enough data are available. However, this estimate can be misled in the sense that there exist many stochastic factors in the EPA\\`s estimation procedures and also throughout the marketing channels of gasoline industry. Addressing the stochasticity problem in EPA\\`s procedure is hard to tackle because the detailed data needed to execute the estimation are not usually available even from refiners. Instead, this research tries to stay focused on the second type of stochasticity issue, raised from the mean0based metrological and marketing practice data collected from the 4 major refiners. To do so emission raters from each marketing channels (8 marketing points by 3 transportation types and by storage facilities of 4 refiners) are estimated monthly, following AP-42 procedures and using Tank 4.0. Once these estimates are acquired, the distribution of VOC emission rate for each marketing channel of all 4 refiners is estimated through simulation method using @Risk. The mean-based emission rates are weighted by company quantities to estimate the emission rate from the whole gasoline industry. Simple economic implication is provided, based on the result. This study found that, on the mean-bases, about 0.66% of gasoline marketed are evaporated into air. Considering the stochasticity in the estimation, about 90% of simulation results fell into the range of 0.65 to 0.68%. For 90% chance, the estimated economic loss is $54.65 million to $57.17 million, not counting the cost caused by air quality degradation and associated health impact.

• Journal of the Korea Institute of Building Construction
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• v.18 no.5
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• pp.499-506
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• 2018

The number of demolition work is rapidly increasing because the middle- and high-rised buildings constructed over the rapid industrialization and urbanization have been deteriorated in social and structural aspects. However, theoretical approaches or studies related to the demolition cost prediction are still insufficient. Thus, this study derived and analyzed important factors affecting the fluctuation of the building demolition costs. 14 factors was derived through literature reviews and experts' interview, and the importance of each factor was analyzed to the each work(temporary work, structure demolition, and waste disposal) and the entire demolition work by using descriptive analysis. The survey results showed that the demolition costs was greatly influenced by environmental properties of the site. The results of this study can be used as a basis for estimating the approximate cost of the demolition work.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.10
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• pp.7204-7210
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• 2015

This paper has developed the system for supporting the approximate construction cost and the quantity estimation based on 3D model information in the pre-project planning phase of 3-span continuous cable-bridge with 2-pylons. First of all, we'd analyzed the design information (structural design report, blueprint and quantity) of the existing cable-stayed bridges and derived the design variables of cable-stayed bridges. We developed the BIM wizard that generates a cable-stayed bridge model parametrically based on derived design variables. The principle material quantities of cable-stayed bridge are calculated directly from 3-dimensional bridge model built by using the BIM wizard. Then, we can estimate the construction cost in relation to its quantities and unit cost of cable-stayed bridge. In a result, we have established the system that the construction cost can be estimated more specific than the conventional method (construction estimates per meter or square meter). We hereby will be able to review various alternatives as soon as possible in bidding process.

• Magazine of the Korean Society of Agricultural Engineers
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• v.18 no.1
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• pp.4079-4086
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• 1976

In many reservoir projects, economic considerations will necessitate a design utilizing surcharge. Determination of the most economical combination of surcharge and spillway capacity for a given spillway crest level will require flood routing studies and economic studies of the dam-reservoir-spillway combinations. Many methods of actual flood routing have been devised, each of them with its advantages and disadvantages. Some of these methods are listed below: (1) Arithmetical trial-and-error method. (2) Modified Puls' method (3) Cheng's graphical method (4) Horton's arithmetical method (5) Ekadahl's arithmetical method (6) Digital computer programming. For the purpose of preliminary design and cost estimating of dams and spillways, it is often required to estimate, for a given design flood and spillway crest level. the approximate values of two among the three characteristics of the spillway spillway length, maximum discharge and surcharge depth at maximum discharge, when one of these quantities is given. As is well known, the outflow hydrograph for an ungated overflow spillway assumes the form of a wave-shaped curve with a minimum point for Q=o At zero time and a maximum point for Q=Qmax at its intersection with the falling leg of the inflow hydrograph (see Fig. 4) The shaded area between the inflow and outflow hydrographs represents at the approximate scale the temporary retention Vt. In line with the remarks, draw by free hand the assumed outflow hydrograph with its maximum point for the given Qmax (see Fig. 4) and by planimetration find Vt. From the reservoir capacity curve (Fig. 3) find Vs for the given spillway crest level and make V=Vs+Vt. From the above curve find surcharge water elevation for V and surcharge depth Hmax over spillway crest. From the discharge formula compute {{{{L= { Q} over { { CH}^{3/2 } } }}}} The methed provides a means for a quick and fairly accurate estimation of spillway capacity.

• Journal of Korean Society of Environmental Engineers
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• v.31 no.6
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• pp.428-433
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• 2009

Dissolved oxygen is considered as one of the important water-quality constituents in streams from one century ago and fishes perish in low dissolved oxygen concentration. Environmental scientists and engineers have introduced the deterministic model to estimate dissolved oxygen concentration of streams and recommended the use of the Delta Method (DM), Approximate Delta Method (ADM), Extreme Value Method (EVM) and Optimization Method (OPT) which can be applied in no spatial variation of dissolved oxygen. The diurnal or annual variation of dissolved oxygen is mainly determined from the parameters such as reaeration rate, 1st production rate and respiration rate which are related to dissolved oxygen. Each method was briefly introduced and applied to two sampling sites of Anseong Stream watershed in this paper. The limitation, advantages and disadvantages of each method were reviewed and analyzed after running the each method. From these analyses, the benefit-cost approach to estimate dissolved oxygen effectively in streams was recommended.