• Ceramist
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• v.10 no.3
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• pp.34-47
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• 2007

Photoinduced phenomena in non-crystalline insulators and semiconductors, specifically oxide and chalcogenide glasses, are briefly reviewed with some comments.

• Journal of the Korean Society of Safety
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• v.28 no.6
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• pp.6-10
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• 2013

A numerical reproducibility of the backdraft phenomena in a compartment was investigated. The prediction performance of two combustion models, the mixture fraction and finite chemistry models, were tested for the backdraft phenomena using the FDS code developed by the NIST. The mixture fraction model could not predict the flame propagation in a fuel-air mixture as well as the backdraft phenomena. However, the finite chemistry model predicted the flame propagation in the mixture inside a tube reasonably. In addition, the finite chemistry model predicted well the backdraft phenomena in a compartment qualitatively. The flame propagation inside the compartment, fuel and oxygen distribution and explosive fire ball behavior were well simulated with the finite chemistry model. It showed that the FDS adopted with the finite chemistry model can be an effective simulation tool for the investigation of backdraft in a compartment.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.7 no.11
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• pp.2804-2823
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• 2013

Wireless sensor network (WSN) is a promising technology for monitoring physical phenomena at fine-grained spatial and temporal resolution. However, the typical approach of sending each sensed measurement out of the network for detailed spatial analysis of transient physical phenomena may not be an efficient or scalable solution. This paper focuses on in-network physical phenomena detection schemes, particularly the distributed computation of the boundary of physical phenomena (i.e. event), to support energy efficient spatial analysis in wireless sensor networks. In-network processing approach reduces the amount of network traffic and thus achieves network scalability and lifetime longevity. This study investigates the recent advances in distributed event detection based on in-network processing and includes a concise comparison of various existing schemes. These boundary detection schemes identify not only those sensor nodes that lie on the boundary of the physical phenomena but also the interior nodes. This constitutes an event geometry which is a basic building block of many spatial queries. In this paper, we introduce the challenges and opportunities for research in the field of in-network distributed event geometry boundary detection as well as illustrate the current status of research in this field. We also present new areas where the event geometry boundary detection can be of significant importance.

• Tribology and Lubricants
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• v.14 no.1
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• pp.70-78
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• 1998

Two different friction materials (organic and low-metallic pads) for automotive brakes were studied to investigate the anti-fading phenomena during stop. The anti-fading phenomena were pronounced more in the case of using low metallic friction materials than organic friction materials. The main cause of the anti-fading phenomena was the high dependence of friction coefficient on a sliding speed. The anti-fading was prominent when the initial brake temperature was high in the case of low-metallic friction materials due to the strong stick-slip event at high temperature. On the other hand, the anti-fading was not severe in organic friction materials and the effect was reduced at high braking temperature due to the thermal decomposition of organic friction materials. The strong stickslip phenomena of low metallic friction materials at high temperature induced high torque oscillations during drag test. During this experiment two different braking control modes (pressure controlled and torque controlled modes) were compared. The type of the control mode used for brake test significantly affected the friction characteristics.

• The Journal of the Acoustical Society of Korea
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• v.30 no.5
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• pp.249-254
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• 2011

Inquiring activities on the acoustic phenomena have been carried out by using a sound card installed in a personal computer. A sound card is cheaper and more accessible to the students than the precision equipment such as a function generator or an oscilloscope. The students record the sounds from various acoustic phenomena to the sound card. Then they analyze the frequency spectrums of that sounds by using a program. Inquired phenomena include beat by two tuning forks, sound from Rijke tube, pouring sound, breaking of a wine glass and pop-up sound of a wine bottle. Through these activities students perform quantitative analysis of various phenomena due to superposition, resonance and standing wave.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.10 no.2
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• pp.146-151
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• 2010

This paper proposes a rank-based control method of mutation probability for improving the performances of genetic algorithms (GAs). In order to improve the performances of GAs, GAs should not fall into premature convergence phenomena and should also be able to easily get out of the phenomena when GAs fall into the phenomena without destroying good individuals. For this, it is important to keep diversity of individuals and to keep good individuals. If a method for keeping diversity, however, is not elaborately devised, then good individuals are also destroyed. We should devise a method that keeps diversity of individuals and also keeps good individuals at the same time. To achieve these two objectives, we introduce a rank-based control method of mutation probability in this paper. We set high mutation probabilities to lowly ranked individuals not to fall into premature convergence phenomena by keeping diversity and low mutation probabilities to highly ranked individuals not to destroy good individuals. We experimented our method with typical four function optimization problems in order to measure the performances of our method. It was found from extensive experiments that the proposed rank-based control method could accelerate the GAs considerably.

• Journal of the Korean Ceramic Society
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• v.42 no.12 s.283
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• pp.846-853
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• 2005

For the performance prediction of a planar-type solid oxide fuel cell, the computational analysis of transport phenomena with a simplified treatment of heat generation by the electrochemical reaction is conducted. From the result of the computational analysis, it is shown that the electrochemical reaction is closely related to the transport phenomena inside a solid oxide fuel cell. Transport phenomena including heat and mass transfer influences on the distribution of local current density and, as a result, on the performance characteristics of the fuel cell. Computational analysis is also extended to the parametric study to investigate the performance behavior of the fuel cell with different amount of supplied fuel flow rates. It is also demonstrated that the mathematical formulation and computational procedures proposed in this study can be applied to prove the importance of the specific TPB area in the manufacturing process of electrodes in solid oxide fuel cells.

• Journal of Digital Convergence
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• v.10 no.4
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• pp.347-352
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• 2012

Uncertain physical phenomena of nature are a frequently researched area in emotional engineering technology and visual expression of art. This paper suggests possibility for implementation of physical phenomena (percolation, dispersion, and flow) of nature using Unity 3D engine's particle system, which have already been analyzed in a previous study [1] on modern paintings that emphasized physical properties. This paper proposes an easy implementation method for uncertain physical phenomena of nature for artists experiencing difficulty in acquisition of knowledge on computer graphics programming, providing an idea for engineers conducting research on emotion-based technology.

• Journal of Digital Contents Society
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• v.9 no.3
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• pp.461-470
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• 2008

There are two methods to express natural phenomena using image processing techniques. One is the presentation of simulations for natural phenomena and the other is the display of images based on script. A lot of people used to get the display using vast data and complicated math formulas. When we get the output images in this way, we will have some problems in time and cost. In this paper, we use fluid images excluding using the complicated math formulas, programming, and taking pictures to present the natural phenomena. We construct the library to express the natural phenomena effectively using 2D images and simulation of fog for the background of oriental painting in 3D space.

• Journal of Elementary Mathematics Education in Korea
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• v.18 no.3
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• pp.379-397
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• 2014

According to Kant, time is integral to all human cognitive experiences. Human beings perceive things in the frame of time. Phenomena are perceived in successive way or in coexistent way. In this paper, I argue that the perspective of temporality and atemporality can be a framework to consider the issues of teaching and understanding of mathematical knowledge. Significance of temporal inquiry of atemporal phenomena is discussed with examples of mathematical expressions and geometric figures. Significance of atemporal inquiry of temporal phenomena is also discussed with examples of the sum of natural numbers, geometric pattern, and the probability of two events. Teachers should understand the potential of mathematical tasks from the perspective of temporality and atemporality and provide students with opportunities to inquire temporal phenomena atemporally and atemporal phenomena temporally.