• The Journal of the Korea institute of electronic communication sciences
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• v.8 no.6
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• pp.899-905
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• 2013

In this paper, we focus on how to calibrate multi-cameras easily and how to efficiently detect quad-copters with small-numbered particles. Each particle is a six dimensional vector that is composed of 3D position and 3D orientation of a quad-copter in the space. Due to curse of dimensionality, that leads to explosive computational costs with a large amount of high-dimensioned particles. To detect efficiently, we need to put more particles in very promising spaces and few particles in other spaces. Though computational cost is lowered by minimizing particles, in order to track a quad-copter with multiple cameras in real-time, multiple images from the cameras should be synchronized and analyzed. Therefore, lots of the computations still need to be done. Because of this, GPGPU(General-Purpose computing on Graphics Processing Units) is implemented for parallel computing. This method has been successfully tested and gives accurate results in practical situations.

• Journal of Korean Society for Quality Management
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• v.24 no.4
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• pp.207-223
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• 1996

These days, customers have attached great importance to the function of product liability and quality assurance. In Korea, the single rectifying sampling inspection for attribute (KS A 3105) has been used. But this inspection plan given by tables (KS A 3105) has some defects. There are limitations in the range of applications and irrationality of approximate probability and the double rectifying sampling inspection is not mentioned. Moreover, ATI (average total inspection) does not reflect sampling costs and the loss of nonconforming item. Therefore, the objectives of this study is to develope new algorithms and computer program that provide the optimal sampling inspection plan based on minimum linear costs (single & double inspection plan). The result of this study revealed that the new algorithm is less than KS A 3105 in ATI and basically, double inspection plan is more economical. Also it comes over restrictions in KS A 3105. So, it is definite that the optimal solution can be obtained considering cost factors in manufacturing and sampling process, and costs can be saved in the long term.

• The Korean Journal of Applied Statistics
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• v.7 no.2
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• pp.113-130
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• 1994

The algorithm of Oh and Berger (1993) is extended to handle more general cases where the integrand $f(\theta)$ is not only multimodal but also skewed or has some undetected modes, each having curvature not much different from that of the nearest component. It runs Oh and Berger's algorithm in an iterative way, adding a component in each stage to the mixture importance function from previous stage for better approximation between $f(\theta)$ and the importance function.

• Journal of Climate Change Research
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• v.9 no.4
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• pp.385-398
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• 2018

Although the importance of developing reliable and systematic GHG inventory has increased, the GIS/RS-based national scale LULUCF (Land Use, Land-Use Change and Forestry) sector analysis is insufficient in the context of the Paris Agreement. In this study, the change in $CO_2$ storage of forest land due to land use change is estimated using two GIS/RS methodologies, Sampling and Wall-to-Wall methods, from 2000 to 2010. Particularly, various imagery with sampling data and land cover maps are used for Sampling and Wall-to-Wall methods, respectively. This land use matrix of these methodologies and the national cadastral statistics are classified by six land-use categories (Forest land, Cropland, Grassland, Wetlands, Settlements, and Other land). The difference of area between the result of Sampling methods and the cadastral statistics decreases as the sample plot distance decreases. However, the difference is not significant under a 2 km sample plot. In the 2000s, the Wall-to-Wall method showed similar results to sampling under a 2 km distance except for the Settlement category. With the Wall-to-Wall method, $CO_2$ storage is higher than that of the Sampling method. Accordingly, the Wall-to-Wall method would be more advantageous than the Sampling method in the presence of sufficient spatial data for GHG inventory assessment. These results can contribute to establish an annual report system of national greenhouse gas inventory in the LULUCF sector.

• ETRI Journal
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• v.14 no.4
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• pp.19-27
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• 1992

Since. as is well known, direct computation of the reliability for a large-scaled and complex net work generally requires exponential time, a variety of alternative methods to estimate the network reliability using simulation have been proposed. Monte Carlo sampling is the major approach to estimate the network reliability using simulation. In the paper, a dynamic Monte Carlo sampling method, called conditional minimal cut set (CMCS) algorithm, is suggested. The CMCS algorithm simulates a minimal cut set composed of arcs originated from the (conditional) source node until s-t connectedness is confirmed, then reduces the network on the basis of the states of simulated arcs. We develop the importance sampling estimator and the total hazard estimator and compare the performance of these simulation estimators. It is found that the CMCS algorithm is useful in reducing variance of network reliability estimator.

• Structural Engineering and Mechanics
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• v.9 no.6
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• pp.557-568
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• 2000

As time-variant reliability approaches become increasingly used for service life prediction of the aging infrastructure, the demand for computer solution methods continues to increase. Effcient computer techniques have become well established for the reliability analysis of structural systems. Thus far, however, this is largely limited to time-invariant reliability problems. Therefore, the requirements for time-variant reliability prediction of deteriorating structural systems under time-variant loads have remained incomplete. This study presents a computer program for $\underline{REL}$iability of $\underline{T}$ime-Variant $\underline{SYS}$tems, RELTSYS. This program uses a combined technique of adaptive importance sampling, numerical integration, and fault tree analysis to compute time-variant reliabilities of individual components and systems. Time-invariant quantities are generated using Monte Carlo simulation, whereas time-variant quantities are evaluated using numerical integration. Load distribution and post-failure redistribution are considered using fault tree analysis. The strengths and limitations of RELTSYS are presented via a numerical example.

• School Mathematics
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• v.16 no.4
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• pp.727-743
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• 2014

The concepts of sample and sampling are central to the statistical thinking and foundations of the statistical literacy, so we need to be emphasized their importance in the statistics education. However, many researches which dealt with samples only analyze textbooks or students' responses. In this study, the concept of sample is addressed by a historical consideration which is one aspect of the didactical analysis. Moreover, developing concept of sample is analyzed from the preceding studies about the statistical literacy, considering the sample representativeness and the sampling variability. The results say that the historical process of developing the concept of sample can be divided into three step: understanding the sample representativeness; appearing the sample variance; recognizing the sampling variability. Above all, it is important to aware and control the sampling variability, but many related researches might not consider sample variability. Therefore, it implies that the awareness and control of sampling variability are needed to reflect to the teaching-learing of sample for developing the students' statistical literacy.

• Progress in Superconductivity and Cryogenics
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• v.24 no.2
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• pp.23-26
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• 2022

A lossless transport of an arbitrary waveform in a frequency range of 10⁶-10⁹ Hz through a conduction channel in a cryogenic temperature is of importance for a high-speed operation of quantum device. However, it is hard to use a commercial oscilloscope to directly detect the waveform travelling in a device located in a cryogenic system. Here, we developed a cryogenic voltage sampling technique by using a Schottky barrier gate prepared on a surface of a GaAs/AlGaAs device, which revealed that an incident rectangle waveform can transport through a 1 mm long two-dimensional conduction channel without waveform deformation up to 20 MHz, while further study is needed to increase the detection frequency.

• Journal of Korean Library and Information Science Society
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• v.39 no.4
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• pp.51-69
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• 2008

This study tired to develop the web credibility evaluation model by calculating weighted values and sensitivities of indicators which presented on preceding researches using Analytic Hierarchy Process. "Expert Choice 2000" was used as the tool for analysing AHP. 25 experts are answered for this questionnaire who are selected by judgement sampling method, one of the non-probability sampling method. Also, sensitivity analyses was performed to graphically see how the alternatives change with respect to the importance of the indicators or sub-indicators. The main results are summarized as followings; i) importance analysis in first level factors: trust-worthiness(0,606), expertness(0.222), safety(0.173), ii) importance analysis in second level factors: trustfulness (0.519), reputation(0.087), usefulness (0.102), timeliness(0,093), competency(0.027), security(0.115), reliability(0,058). iii) some of the importance analysis in third level factors: the site provides comprehensive information that is attributed to a specific source(0.252), the site has articles that list citations and references(0.153), the site contains user opinions and reviews(0.072), etc. iv) sensitivity analyses showed that the importance of the indicators or sub-indicators are slightly changed with respect to the alternatives change.

• Journal of the Korean GEO-environmental Society
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• v.23 no.7
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• pp.11-20
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• 2022

Planetary geotechnical investigation in charge of drilling and soil sampling is of a great importance in providing extraterrestrial geotechnical information. Extraterrestrial subsurface investigation, which includes drilling, soil sampling, and sample transportation, will be loaded in a lander or a rover. Scientists from all over the world are interested in the design and development of a drilling system with various functions due to potential applications in planetary surface exploration mission. However, it is difficult to build a fully functional drilling system in extreme environment conditions. This paper presents engineering considerations for the design and development of soil sampling including drilling and performance verification in extreme environment conditions in detail.