• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.31 no.8
• /
• pp.27-35
• /
• 2003

Geometric modeling tool and analysis tool of shell surface have been developed in the different environments and purposes. Thus they cannot be naturally fitted to each other for the integrated design and analysis. In the present study, an integrated framework of geometric modeling, analysis， and design optimization is proposed. It is based on the common representation of B-spline surface patch. In the analysis module, a geometrically-exact shell finite element is implemented. In shape optimization module, control points of the surface are selected as design variables. For the computation of shape sensitivities, semi-analytical method is used. Sequential linear programming(SLP) is adopted for the shape optimization of surfaces. The developed integrated framework should serve as a powerful tool for the geometric modeling, analysis, and shape design of surfaces.

• The Journal of the Korea Contents Association
• /
• v.17 no.7
• /
• pp.1-11
• /
• 2017

The best business strategy leading to innovation and productivity can be achieved by carefully analyzing internal and external environments of a company. Many companies often require, but difficult to find a tool to determine their own internal/external environmental factors including strengths, weaknesses, opportunities and threats(SWOT). SWOT is one analytical base model that is utilized in this research to design semi-automated environmental analysis process. This study investigates on SWOT generation system that is built on existing analysis database created by experts in each field. Companies can search and choose their best expressing environmental elements that are stored in the database. This semi-automated SWOT tool is expected to contribute that companies can recognize their internal capabilities more accurately, and help consider external environment changes around them.

• Journal of Korea Game Society
• /
• v.15 no.4
• /
• pp.121-132
• /
• 2015

This study suggests a design for an analytical software program and method for multitasking e-sports viewing through the web using an eye tracking device. To fulfill this task, we designed a Window of Interest (WOI) to measure and record visually on a screen wherever numerous multitasking activities occur. In addition, we developed an OBS (Opensource Broadcaster Software) plug-in that records and streams participant viewing behavior patterns in real time. The purpose of this study is as follows. First, unlike existing tools that limit web interface recording to still images, the developed tool can record dynamically via media such as videos. Second, when several windows are processed on a screen, the tool can accurately record the gaze positions of the participants. Lastly, the tool can enhance the objective validity of the data as it can be implemented in natural situations. Therefore, this study can trace natural viewing patterns and behavior as we do not create artificial experimental environments and stimuli.

• Coupled systems mechanics
• /
• v.4 no.4
• /
• pp.279-295
• /
• 2015

The article presents a theoretical-experimental approach developed for modeling the coefficient of sliding friction in the dynamic system tool-workpiece in slide diamond burnishing of low-alloy unhardened steels. The experimental setup, implemented on conventional lathe, includes a specially designed device, with a straight cantilever beam as body. The beam is simultaneously loaded by bending (from transverse slide friction force) and compression (from longitudinal burnishing force), which is a reason for geometrical nonlinearity. A method, based on the idea of separation of the variables (time and metric) before establishing the differential equation of motion, has been applied for dynamic modeling of the beam elastic curve. Between the longitudinal (burnishing force) and transverse (slide friction force) forces exists a correlation defined by Coulomb's law of sliding friction. On this basis, an analytical relationship between the beam deflection and the sought friction coefficient has been obtained. In order to measure the deflection of the beam, strain gauges connected in a "full bridge" type of circuit are used. A flexible adhesive is selected, which provides an opportunity for dynamic measurements through the constructed measuring system. The signal is proportional to the beam deflection and is fed to the analog input of USB DAQ board, from where the signal enters in a purposely created virtual instrument which is developed by means of Labview. The basic characteristic of the virtual instrument is the ability to record and visualize in a real time the measured deflection. The signal sampling frequency is chosen in accordance with Nyquist-Shannon sampling theorem. In order to obtain a regression model of the friction coefficient with the participation of the diamond burnishing process parameters, an experimental design with 55 experimental points is synthesized. A regression analysis and analysis of variance have been carried out. The influence of the factors on the friction coefficient is established using sections of the hyper-surface of the friction coefficient model with the hyper-planes.

• The Mathematical Education
• /
• v.60 no.2
• /
• pp.159-172
• /
• 2021

The purpose of this study is to compare and analyze the effects of physical manipulative and exploratory geometry software on the spatial sense for 5^th grade elementary school students in learning nets. For this purpose, ton experimental group used Geofix, an operational learning tool, and the experimental group used Cabri 3D, an exploratory geometry software to learn the nets of solids. The comparison group was learned by worksheet only without any manipulative or software. Spatial sense tests were conducted before and after to determine the level, and eye tracking were used to analyze the strategies of students in solving nets problems. As a result, it was confirmed that the using Geofix group was the most effective for the spatial sense, and Cabri 3D could also be a good tool for learning the nets of solids. In addition, after learning the nets of solids, the analytical strategy, which was the most effective strategy for students' solving strategies, increased. In the process of solving spatial tasks such as the spatial sense tasks, eye tracking technology become a very useful tool for exploring students' strategies, so it is expected that objective and useful data will be collected through more active use in the future.

• Journal of the Korean Association of Geographic Information Studies
• /
• v.19 no.1
• /
• pp.1-11
• /
• 2016

Climate change is the issue that attracts the most attention in the field of environment, as well as the most challenging task faced by the human race. There are various ways to resolve this issue. South Korea has established the primary and secondary national climate change adaptation plans at the national level, and is making it compulsory for each local government (lower and municipal-level) to establish climate change adaptation plans. Climate change vulnerability assessment plays an essential role in establishing climate change adaptation action plans. However, vulnerability assessment has a difficulty performing individual assessments since the results are produced through complex calculations of multiple impact factors. Accordingly, this study developed a web-based supporting tool(VESTAP) for climate change vulnerability assesment that can be used by lower and municipal-level local governments. The VESTAP consists of impact DB and vulnerability assessment and display tool. The index DB includes total 455 impacts of future climate data simulated with RCP (Representative Concentration Pathways) 4.5 and 8.5, atmospheric environment data, other humanities and social statistics, and metadata. The display tool has maximized convenience by providing various analytical functions such as spatial distribution, bias and schematization of each vulnerability assessment result. A pilot test of health vulnerability assessment by particulate matters in Sejong Metropolitan Autonomous City was performed using the VESTAP, and Bukang-myeon showed the highest vulnerability. By using the developed tool, each local government is expected to be able to establish climate change adaptation action plans more easily and conveniently based on scientific evidence.

• Journal of the Korea Society of Computer and Information
• /
• v.15 no.11
• /
• pp.143-156
• /
• 2010

Faced with an increase of malicious threats from the Internet as well as local area networks, many companies are considering deploying a security system. To help a decision maker select a suitable security tool, this paper proposed a three-step integrated framework using linear fuzzy regression (LFR) and physical programming (PP). First, based on the experts' estimations on security criteria, analytic hierarchy process (AHP) and quality function deployment (QFD) are employed to specify an intermediate score for each criterion and the relationship among these criteria. Next, evaluation value of each criterion is computed by using LFR. Finally, a goal programming (GP) method is customized to obtain the most appropriate security tool for an organization, considering a tradeoff among the multi-objectives associated with quality, credibility and costs, utilizing the relative weights calculated by the physical programming weights (PPW) algorithm. A numerical example provided illustrates the advantages and contributions of this approach. Proposed approach is anticipated to help a decision maker select a suitable security tool by taking advantage of experts' experience, with noises eliminated, as well as the accuracy of mathematical optimization methods.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 2008.10a
• /
• pp.254-258
• /
• 2008

Dimensional accuracy is very important quality in micro forged part, especially on forged part. Dimension of forged part is changed continuously during forging process. Loading, unloading and ejecting stage affects dimensional of the forged tool. The elasto-plastic material model for billet and elastic model for die were used to analyze these changes. At same time, the calculated results were compared and analyzed by the experiment on same conditions. From the experimental and analytical studies, we can calculated the amount of difference between die and forged part, that is 0.49% based on the die dimension. The dimensional change is smaller than that of general sized-forged part,0.6%.

• Journal of Mechanical Science and Technology
• /
• v.17 no.3
• /
• pp.321-328
• /
• 2003

The elongation of contact length on the line of action is considered with particular reference for roll forming of gears, and for dynamic behavior of the tooth in meshing. However there is no paper that discuss the elongation of contact length in the load meshing of gears. Based on our investigation, the contact length on the line of action elongates more than the kinematically calculated value. In rolling, as the tool approaches the workpiece, the center distance of the gears decreases by a small amount. But, the elongation of contact length is sensitive. Therefore, the contact point on the line of action is difficult to be determined, which complicates the tooth analysis. In this study, the exact relation between the elongation of contact length and the tooth space over the recess or before the approach are revealed by experiments and kinematic theory. This analytical result applies not only for rolling, but also for the single flank meshing which is done under constant center distance.

• International Journal of Human Ecology
• /
• v.4 no.2
• /
• pp.77-87
• /
• 2003

This paper tried to construct statistical and econometric models on the basis of economic theory in order to discuss the issue of statistical efficiency and unbiasedness including the sample selection bias correcting problem. Comparative analytical tool were one stage Tobit of Maximum Likelihood estimation and Heckman's two-step Tobit of Ordinary Least Squares. The results showed that the adequacy of model for the analysis on demand and choice, we believe that there is no big difference in explanatory variables between the first selection model and the second linear probability model. Since the Lambda, the self- selectivity correction factor, in the Type II Tobit is not statistically significant, there is no self-selectivity in the Type II Tobit model, indicating that Type I Tobit model would give us better explanation in the demand for and choice which is less complicated statistical method rather than type II model.