• KSII Transactions on Internet and Information Systems (TIIS)
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• v.18 no.7
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• pp.1774-1794
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• 2024

In the field of environmental sensing, it is necessary to develop radio planning techniques for the next generation Internet of Things (IoT) networks over mixed terrains. Such techniques are needed for smart remote monitoring of utility supplies, with links situated close to but out of range of cellular networks. In this paper, a three-dimension (3-D) geometric optimization algorithm is proposed, considering the positions of edge IoT devices and antenna coupling factors. Firstly, a multi-level single linkage (MLSL) iteration method, based on geometric objectives, is derived to evaluate the data rates over ISM 915 MHz channels, utilizing optimized power-distance profiles of continuous waves. Subsequently, a federated learning (FL) data selection algorithm is designed based on the 3-D geometric positions. Finally, a measurement example is taken in a meadow biome of the Mexican Colima district, which is prone to fluvial floods. The empirical path loss model has been enhanced, demonstrating the accuracy of the proposed optimization algorithm as well as the possibility of further prediction work.

• Fashion & Textile Research Journal
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• v.15 no.4
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• pp.504-513
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• 2013

This study evaluates the difference of visual effect according to pant style and geometric pattern. The researcher made 28 stimuli-combination of four pant Stiles (classic, baggy, skinny, and bell-bottom) and seven geometric pattern (large vertical stripe, small vertical stripe, large horizontal stripe, small horizontal stripe, large check, small check, and hound's tooth check). The test involved 96 female college students. The stimuli were made with the i-Designer computer program. The panels tested the computer screen images of all manikins wearing pants. A 7-point scale was used to evaluate each image. For the data analysis, ANOVA and Duncan-test were applied along with an SPSS program. The results of this study are as follows. Three factors (lower-body compensation, abdomen highlight, and length compensation) influenced the visual effect pant styles and geometric patterns. The skinny style and large vertical stripe evaluated positively in elongated height and leg length and a slimmer overall body. It was shown that the vertical stripe pattern was evaluated as more positive than the horizontal stripe pattern in the visual effect; particularly, the results showed distinct aspects in the classic pants style. The mutual influence of the visual effect (according to pants style and geometric pattern) were indicated as two factors of lower-body compensation and length compensation. A more positive visual effects resulted in a higher mutual influence on pant style and geometric pattern.

• Journal of the Korean Society for Precision Engineering
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• v.15 no.6
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• pp.58-63
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• 1998

There are lots of factors that are related to the geometric characteristics of machined surface. Among them, the tool path and milling mode (up cut milling or down cut milling) are the easiest controllable machining conditions. Thus, the first objective of this research is to study the effects of them on the milled surface that is generated by an end milling tool. To get precision parts, not only the machining process but also the measurement of geometric tolerance is important. But, this measurement requires a lot of time, because the infinite surface points must be measured in the ideal case. So, the second objective is to propose a simple flatness measurement method that can be available instead of the 3-D geometric tolerance measurement method, using a scale factor and characterized points. Finally, it is also shown that the possibility of flatness improvement by shifting the consecutive fine cutting tool path as compared with the last rough cutting tool path.

• Proceedings of the KSRS Conference
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• v.1
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• pp.504-507
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• 2006

Airborn Lidar technology has been applied to diverse applications with the advantages of accurate 3D information. Further, Lidar intensity, backscattered signal power, can provid us additional information regarding target's characteristics. Lidar intensity varies by the target reflectance, moisture condition, range, and viewing geometry. This study purposes to generate normalized airborne LiDAR intensity image considering those influential factors such as reflectance, range and geometric/topographic factors (scan angle, ground height, aspect, slope, local incidence angle: LIA). Laser points from one flight line were extracted to simplify the geometric conditions. Laser intensities of sample plots, selected by using a set of reference data and ground survey, werethen statistically analyzed with independent variables. Target reflectance, range between sensor and target, and surface slope were main factors to influence the laser intensity. Intensity of laser points was initially normalized by removing range effect only. However, microsite topographic factor, such as slope angle, was not normalized due to difficulty of automatic calculation.

• Journal of Korean Society for Geospatial Information Science
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• v.24 no.2
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• pp.79-87
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• 2016

As 3D geospatial information is demanded, terrestrial laser scanners which can obtain 3D model of objects have been applied in various fields such as Building Information Modeling (BIM), structural analysis, and disaster management. To acquire precise data, performance evaluation of a terrestrial laser scanner must be conducted. While existing 3D surveying equipment like a total station has a standard method for performance evaluation, a terrestrial laser scanner evaluation technique for users is not established. This paper categorizes and analyzes error sources which generally occur in terrestrial laser scanning. In addition to the prior researches about categorizing error sources of terrestrial Laser scanning, this paper evaluates the error sources by the actual field tests for the smooth in-situ applications.The error factors in terrestrial laser scanning are categorized into interior error caused by mechanical errors in a terrestrial laser scanner and exterior errors affected by scanning geometry and target property. Each error sources were evaluated by simulation and actual experiments. The 3D coordinates of observed target can be distortedby the biases in distance and rotation measurement in scanning system. In particular, the exterior factors caused significant geometric errors in observed point cloud. The noise points can be generated by steep incidence angle, mixed-pixel and crosstalk. In using terrestrial laser scanner, elaborate scanning plan and proper post processing are required to obtain valid and accurate 3D spatial information.

• Journal of Information Display
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• v.13 no.1
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• pp.43-49
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• 2012

Depth sensitivity is considered one of the factors influencing 3D displays the most. In this paper, the perceptual 3D depth was quantitatively measured to compare the depth difference among the display devices. No difference was found in the typical display performance among the devices, but the subjective evaluation of the depth sensitivity where the disparity was varied showed that the organic light emitting diode (OLED) had the highest performance, mainly due to its almost 0% crosstalk, one of the features of OLED. Crosstalk is a form of image superposition that greatly affects the depth sensitivity. The experiment results showed that the quantitative depth sensitivity varies due to geometric factors such as disparity, viewing distance, and subjective sensitivity, depending on the display image characteristics, such as crosstalk and contrast.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.173-174
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• 2006

Understanding chondrocyte behavior inside complex, three-dimensional environments with controlled patterning of geometrical factors would provide significant insights into the basic biology of tissue regenerations. One of the fundamental limitations in studying such behavior has been the inability to fabricate controlled 3D structures. To overcome this problem, we have developed a three-dimensional microfabrication system. This system allows fabrication of predesigned internal architectures and pore size by stacking up the photopolymerized materials. Photopolymer SL5180 was used as the material for 3D scaffolds. The results demonstrate that controllable and reproducible inner-architecture can be fabricated. Chondrocytes harvested from human nasal septum were cultured in two kinds of 3D scaffolds to observe cell adhesion behavior. Such 3D scaffolds might provide effective key factors to study cell behavior in complex environments and could eventually lead to optimum design of scaffolds in various tissue regenerations such as cartilage, bone, etc. in a near future.

• Proceedings of the Optical Society of Korea Conference
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• 2000.02a
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• pp.270-271
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• 2000

Among many optical modulators, we are interested in traveling-wave(TW) multiple quantum well(MQW) electro-absorption modulator which can be used for wide-band applications, covering DC to 30GHz or higher frequencies. In this study, we simulate a 1.3mm InGaAs/lnGaAsP TW MQW EAM using the 3D Finite Difference-Time Domain (FDTD) method. We identify that several geometric factors affect Microwave charateristics. Our calculated data provide useful information to optimize and fabricate ridge-type TW CPW EAM.

• Clinical and Experimental Pediatrics
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• v.59 no.3
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• pp.114-119
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• 2016

Purpose: This study aimed to assess the reference values and factors influencing blood lead levels among Korean adolescents. Methods: The study population consisted of 1,585 adolescents (801 males, 784 females; aged 10-19 years) who participated in the Korea National Health and Nutrition Examination Survey 2010-2013. We analyzed blood lead concentrations in relation to demographic/lifestyle characteristics for all participants. "Reference values" of blood lead levels were calculated as the upper limit of the 95% confidence interval of the 95th percentile. Results: The average "reference value" for blood lead concentrations among Korean adolescents was $2.25{\mu}g/dL$ ($2.49{\mu}g/dL$ for males, $2.07{\mu}g/dL$ for females), and the geometric mean of the blood lead concentrations was $1.34{\mu}g/dL$. Males had higher blood lead concentrations than females (male, $1.48{\mu}g/dL$; female, $1.19{\mu}g/dL$; P<0.001). Elementary school students had higher blood lead concentrations than junior and senior high school students ($1.44{\mu}g/dL$ vs. $1.31{\mu}g/dL$, P<0.001). Participants living in detached houses had higher blood lead concentrations than those living in apartments (P<0.001) and current smokers had higher concentrations than nonsmokers or participants with secondhand smoke exposure (P<0.05). Additionally, participants with excessive alcohol consumption had higher levels than non-drinkers (P<0.001). Conclusion: This study provides national reference data on blood lead concentrations stratified by demographic and lifestyle factors among Korean adolescents. Further studies are needed to elucidate the relationship between increased lead exposure and demographic factors including type of housing.

• Journal of Cadastre & Land InformatiX
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• v.52 no.1
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• pp.37-55
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• 2022

This study presents the plans to derive quality items for develop the data quality standard for ensuring the quality of 3D building geospatial data in NDT(National Digital Twin). This paper is organized as follows. The first section briefly examines various factors that impact the quality of 3D geospatial data, and proposes the role and necessity of the data quality standard as a means of addressing the data errors properly and also meeting the minimum requirements of stakeholders. The second section analyzes the relationship between the standards - building data model for NDT and ISO 19157: Geospatial data quality - in order to consider directly relevant standards. Finally, we suggest three plans on developing NDT data quality standard: (1) the scope for evaluating data quality, (2) additional quality elements(geometric integrity, geometric fidelity, positional accuracy and semantic classification accuracy), and (3) NDT data quality items model based on ISO 19157. The plans reveled through the study would contribute to establish a way for the national standard on NDT data quality as well as the other standards associated with NDT over the coming years.