• Journal of Periodontal and Implant Science
• /
• v.48 no.2
• /
• pp.84-91
• /
• 2018

Purpose: The purpose of this study was to visualize and identify peri-implant bone defects in optical coherence tomography (OCT) images and to obtain quantitative measurements of the defect depth. Methods: Dehiscence defects were intentionally formed in porcine mandibles and implants were simultaneously placed without flap elevation. Only the threads of the fixture could be seen at the bone defect site in the OCT images, so the depth of the peri-implant bone defect could be measured through the length of the visible threads. To analyze the reliability of the OCT measurements, the flaps were elevated and the depth of the dehiscence defects was measured with a digital caliper. Results: The average defect depth measured by a digital caliper was $4.88{\pm}1.28mm$, and the corresponding OCT measurement was $5.11{\pm}1.33mm$. Very thin bone areas that were sufficiently transparent in the coronal portion were penetrated by the optical beam in OCT imaging and regarded as bone loss. The intraclass correlation coefficient between the 2 methods was high, with a 95% confidence interval (CI) close to 1. In the Bland-Altman analysis, most measured values were within the threshold of the 95% CI, suggesting close agreement of the OCT measurements with the caliper measurements. Conclusions: OCT images can be used to visualize the peri-implant bone level and to identify bone defects. The potential of quantitative non-invasive measurements of the amount of bone loss was also confirmed.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.25 no.3
• /
• pp.296-303
• /
• 2014

In this paper, we propose an algorithm to visualize radio wave environment based on the measured Received Signal Strength Indication( RSSI) and 3D geographic information. We estimate the source position using the circumcenter of the triangle and visualize the radio wave environment using the empirical propagation models. A mode seeking algorithm(mean-shift clustering) is used to seek the peak points and the center of gravity is utilized to reduce the estimation errors. Our approach finds its applications in the radio wave monitoring systems for the efficient utilization of radio resources.

• Journal of the Korean Data and Information Science Society
• /
• v.28 no.1
• /
• pp.87-98
• /
• 2017

The multivaiate empirical distribution function (MEDF) is defined in this work. The MEDF's expectation and variance are derived and we have shown the MEDF converges to its real distribution function. Based on random samples from bivariate standard normal distribution with various correlation coefficients, we also obtain MEDFs and propose two kinds of graphical methods to visualize MEDFs on two dimensional plane. One is represented with at most n stairs with similar arguments as the step function, and the other is described with at most n curves which look like bivariate quantile vector. Even though these two descriptive methods could be expressed with three dimensional space, two dimensional representation is obtained with ease and it is enough to explain characteristics of bivariate distribution functions. Hence, it is possible to visualize trivariate empirical distribution functions with three dimensional quantile vectors. With bivariate and four variate illustrative examples, the proposed MEDFs descriptive plots are obtained and explored.

• The Journal of the Korea Contents Association
• /
• v.15 no.10
• /
• pp.37-45
• /
• 2015

The importance of cultural contents industry is steadily growing owing to the Korean wave etc. and Buddhist cultural contents is a part of the cultural contents. However, the development of Buddhist cultural contents in many ways has left much to be desired. That is because, it is difficult for the public, who is not Buddhist scholar, to understand and take interest in conventional contents on Buddhist books themselves which are digitalized. Also, most contents researches are discussed on the necessity of contents development and just stay in these subjects, but it is insufficient to study a semantic analysis and visualizing contents on Buddhist books. So, in this paper, we analyse mandala's twinning rite in the Buddhist books and implement visual contents on the rite. The mandala is using toohadeokbul in a special way as the abhisinca rite. We analyse concept of the toohadeokbul and implement its visual contents which visualize ideological logic of Buddhism. The implemented contents are able to provide the public with Buddhist cultural experience of the yard. Additional, by trying to visualize descriptive expressions of Buddhist books, this paper could be a precedent for developing visual contents of unlimited data comprised in Buddhist books.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.41 no.1
• /
• pp.37-46
• /
• 2017

Thermal Marangoni flow has been observed inside droplets on heated surfaces, finally resulting in a coffee stain effect. This study aims to visualize and control the thermal Marangoni flow by employing periodic vertical vibration. The variations in the contact angle and internal volume of the droplet as it evaporates is observed by using a combination of continuous light and a still camera. With regard to the internal velocity, the particle image velocimetry system is applied to visualize the internal thermal Marangoni flow. In order to estimate the internal temperature gradient and surface tension on the surface of a droplet, the theoretical model based on the conduction and convection theory of heat transfer is applied. Thus, the internal velocity increases with an increase in plate temperature. The flow directions of the Marangoni and gravitational flows are opposite, and hence, it may be possible to control the coffee stain effect.

• KIPS Transactions on Software and Data Engineering
• /
• v.9 no.2
• /
• pp.69-76
• /
• 2020

In this paper, we introduce a method to visualize the contrast diffusion patterns and the dynamic vascular patterns in a contrast-enhanced ultrasound image sequence. We present an imaging technique to visualize parameters such as contrast arrival time, peak intensity time, and contrast decay time in contrast-enhanced ultrasound data. The contrast flow pattern and its velocity are important for characterizing focal liver lesions. We propose a method for representing the contrast diffusion patterns as an image. In the methods, respiratory motion may degrade the accuracy of the parametric images. Therefore, we present a respiratory motion tracking technique that uses dynamic weights and a momentum factor with respect to the respiration cycle. Through the experiment using 72 CEUS data sets, we show that the proposed method makes it possible to overcome the limitation of analysis by the naked eye and improves the reliability of the parametric images by compensating for respiratory motion in contrast-enhanced ultrasonography.

• The Journal of the Korea Contents Association
• /
• v.10 no.4
• /
• pp.397-405
• /
• 2010

This study proposes visualization methods of the diurnal passenger flows on the Metropolitan Seoul Subway system (MSSs) and examines the passenger trip behaviors of major central business districts (CBDs). We mine the MSS passenger flow information from a single day T-card passenger trip transaction database. It is practically intractable to analyze such flows, involving huge, complex space-time data, by means of general statistical analysis. On the other hand, dynamic visualizations of the passenger flows make it possible to analyze intuitively and to grasp effectively characteristics of the passenger flows. We thus propose several methods to visualize the passenger flow information. In particular, we visualize dynamic passenger flows of each link on the subway network and analyze the time-space characteristics of passenger ridership for the three major CBDs. As the result, we can ascertain the strong association between CBD and subway line and clarify the distinction among three major CBDs in the diurnal patterns of subway passenger flow.

• Journal of the Society of Naval Architects of Korea
• /
• v.29 no.4
• /
• pp.7-17
• /
• 1992

Developments in the emerging field of Computational Fluid Dynamics(CFD), which is made possible by the supercomputer technologies, introduce a new problem of analysing the massive amount of output produced. This problem is common to fields of computational science and engineering. Scientific visualization is to solve this problem by applying advanced technologies of computer graphics. Methods of scientific visualization are studded to visualize calculated flow fields. Different methods of scientific visualization has been surveyed, analysed and compared to select one method, iso-surface. Methods of constructing iso-surfaces from a 3-D data set have been studied. A new algorithm for constructing iso-surfaces has been developed. The algorithm can be classified as one of surface tiling methods. To develope a portable visualization system the international standard PHIGS PLUS and its implementation on X-Window system, PEX, have been selected as the development environment. A prototype of visualization system has been developed. The developed visualization system has been tried to visualize several well-known flow fields.

• Journal of Digital Convergence
• /
• v.14 no.2
• /
• pp.209-216
• /
• 2016

In these days, considering the trend to make various information blended based on spatial information like road, buildings and geography, it is to be very important to visualize maps for showing the information efficiently. However, geometry which is composed with line, polygon commonly used on web service has limitation to express information by limit of usage as well as spending certain time to show the information via map. That's why this study develops the efficient way to visualize huge and complex spatial information. This way is to bring partial space with spatial query, and then query and expand information excluded the former area after detecting movement event based on client. When the way is implemented, it will be expected to make efficient visualization in entire system by not bringing unnecessary information but shortening spending time to show area because it just shows areas which clients want to see.

• The Mathematical Education
• /
• v.45 no.2 s.113
• /
• pp.191-204
• /
• 2006

Computer technology has a potential to change the contents of school mathematics and the way of teaching mathematics. But in our country, the problem whether computer technology should be introduced into mathematics classroom or not was not resolved yet. As a tool, computer technology can be used by teachers who are confident of the effectiveness and who can use it skillfully and can help students to understand mathematics. The purpose of this study was to investigate the effective way to introduce and utilize computer technology based on the status quo of mathematics classroom setting. One possible way to utilize computer technology in mathematics classroom in spite of the lack of computer and the inaccessibility of useful software is using domain specific simulation software like 'Polyhedron'. 'Polyhedron', as we can guess from the name, can be used to explore regular and semi regular polyhedra and the relationship between them. Its functions are limited but it can visualize regular polyhedra, transform regular polyhedra into other polyhedra. So it is easier to operate than other dynamic geometry software like GSP. To investigate the effect of using this software in mathematics class, three classes(one in 6th grade from science education institute for the gifted, two in 7th grade) were chosen. Activities focused on the relationship between regular and semi regular polyhedra. After the class, several conclusions were drawn from the observation. First, 'Polyhedron' can be used effectively to explore the relationship between regular and semi regular polyhedra. Second, 'Polyhedron' can motivate students. Third, Students can understand the duality of polyhedra. Fourth, Students can visualize various polyhedra by reasoning. To help teachers in using technology, web sites like NCTM's illuminations and NLVM of Utah university need to be developed.