• International Journal of Vascular Biomedical Engineering
• /
• v.1 no.2
• /
• pp.30-35
• /
• 2003

Flow characteristics of blood flow in a micro channel were investigated experimentally using a micro-PIV (Particle Image Velocimetry) velocity field measurement technique. The main objective of this study was to understand the real blood flow in micron-sized blood vessels. The Reynolds number based on the hydraulic diameter of micro-channel for deionized (DI) water was about Re=0.34. For each experimental condition, 100 instantaneous velocity fields were captured and ensemble-averaged to get the spatial distributions of mean velocity. In addition, the motion of RBC (Red Blood Cell) was visualized with a high-speed CCD camera. The captured flow images of nano-scale fluorescent tracer particles in DI water were clear and gave good velocity tracking-ability. However, there were substantial velocity variations in the central region of real blood flow in a micro-channel due to the presence of red blood cells.

• Journal of information and communication convergence engineering
• /
• v.8 no.2
• /
• pp.185-190
• /
• 2010

In this paper we propose the CBIR algorithm which is based on a novel image block method that combined both color and edge feature. The main drawback of global histogram representation is dependent of the color without spatial or shape information, a new image block method that divided the image to 8 related blocks which contained more information of the image is utilized to extract image feature. Based on these 8 blocks, histogram equalization and edge detection techniques are also used for image retrieval. The experimental results show that the proposed image block method has better ability of characterizing the image contents than traditional block method and can perform the retrieval system efficiently.

• Journal of the Optical Society of Korea
• /
• v.17 no.2
• /
• pp.130-135
• /
• 2013

Based on the extended Huygens-Fresnel principle and generalized Stokes theory, the evolution of polarization properties of beams generated by quasi-homogenous (QH) sources propagating in clear oceanic water was studied by the use of the oceanic turbulence spatial spectrum function. The results show that the beams have similar polarization self-reconstructed behavior under different turbulence conditions in the far field, but if the propagation distance is not long enough, the degree of polarization (DOP) fluctuates with much more complexity than state of polarization (SOP) of QH beams. The self-reconstructed ability of DOP at the special distance in turbulence would get to the best value if the values of coherence of width were chosen suitably, but for SOP, it has no best value.

• Journal of the Korean Society for Aviation and Aeronautics
• /
• v.14 no.1
• /
• pp.63-69
• /
• 2006

The operational environment of helicopters extends from the civil air traffic control system to remote and hazardous areas and from day operations under visual flight conditions to night operations in adverse weather. Helicopters can move in any direction, remain stationary while airborne, climb and descend vertically, and take off and land almost anywhere. Thus their range of maneuvers and control requirements vary more widely than do those of fixed-wing aircraft. In this study, I analyzed the job of helicopter pilot through methods of observation, and classified the required ability of them into the domain of cognitive, perceptual/spatial, psychomotor. I expect that the result of this study will be used to aid training and selection of helicopter pilot.

• Proceedings of the KSRS Conference
• /
• 2003.11a
• /
• pp.795-797
• /
• 2003

GIS can supply large quantitiy of useful information about spacial relationship, consequently there exists great potential of GIS support ing for decision making strategies related to urban design and environmental planning. In different discipline areas there exist different information representation methods and considerations having direct or indirect relationship with spacial information, how to use GIS as a tool for facilitating the work in other discipline field, there are two basic questions crucial to the success of these interdiscipline applications. The first one is interoperatability among GIS and other applications, the second is the paradigm difference between GIS and other domain field regarding problem solving. In this paper, we investigate the spatial information of the urban environment provided in the analyses of the urban visual sustain ability, urban daylighting environment and urban wind environment. We also discuss the challenges and opportunities for cross-disciplinary GIS application regarding the aspect of Information Collection, Information Generation, Information Analysis and Information Visualization.

• 한국연소학회:학술대회논문집
• /
• 2000.12a
• /
• pp.183-193
• /
• 2000

Soot formation and oxidation is closely related to the combustion phenomena inside a diesel engine. Laser-based diagnostics provide a means for improving our understanding of diesel combustion, because they have highly temporal and spatial ability. To understand the soot behavior we did preliminary study by taking flame luminosity photographs and 2-D images of soot distribution using Laser Elastic Scattering(LIS) and Laser-Induced Incandescence(LII). From the data we found that soot concentration was high in the bowl and disappeared from the central region in the late combustion stage and that soot exists in the flame using luminosity, LIS and LII.

• School Mathematics
• /
• v.3 no.2
• /
• pp.447-473
• /
• 2001

Since the greater part of mathematical concepts have been developed in the direction of “from the concrete and realistic aspects to the abstract level”, children should be secured to learn mathematics genetically with various manipulative materials. The aim of this study is to instigate the active use of geoboards in mathematics classroom. To achieve this arm, we first embodied the several significances on the use of geoboards in mathematics instruction. And we then performed an instruction that children discover and justify the formula related to the area of trapezoid by exploring with geoboards, and analyzed the instructional episode to support our assertion about some secure merit accompanied by using geoboards. From this study, we obtained the conclusion that geoboard activity contains many significances such as children can explore congruence, symmetry, similarity, fundamental properties of figures, and pattern. Futhermore, geoboard activity enable children to transform a figure into other equivalently, develop spatial sense, have basic experiences for coordinate geometry, build a concrete model to explain abstract ideas, and foster the ability of problem solving and mathematical thinking.

• Journal of Korean Elementary Science Education
• /
• v.33 no.2
• /
• pp.286-305
• /
• 2014

We explored the possibilities of science field experience in Jongmyo Shrine in this study. To understand the educational value of self-leading science activities in Jongmyo Shrine, one of the World Heritage, we developed science program and applied it to the elementary students participating in a gifted education center. We collected and analyzed various data of opinionnaire survey before and after the program, field activity sheets, field observation, and individual- and group interview. The results showed the lack of students' spatial ability and proposed educational interests in science education. Also, a lot of students felt the difficulty in applying school science knowledge into the real life context. Students found the meaning of science learning through cooperative activities in the historically meaningful place. A proper use of smart device in science field experience was recommended. We found that activities with too much smart device might impede various scientific process skills.

• Proceedings of the KSME Conference
• /
• 2000.11b
• /
• pp.162-167
• /
• 2000

Soot formation and oxidation is closely related to the combustion phenomena inside a diesel engine. Laser-based diagnostics provide a means for improving our understanding of diesel combustion, because they have highly temporal and spatial ability. To understand the soot behavior we did preliminary study by taking flame luminosity photographs and 2-D imaging soot distribution using Laser Elastic Scattering(LIS) and Laser-Induced Incandescence(LII). From the data we found that soot concentration was high in the bowl and disappeared from the central region in the late combustion stage.

• Journal of the Korean Society for Precision Engineering
• /
• v.15 no.1
• /
• pp.60-68
• /
• 1998

Parallel link manipulators have an ability of more precise positioning than serial open-loop manipulators. However. general parallel link manipulators have been restricted to the real applications since they have limited workspace due to interference among actuators. In this study, we suggest a closed-loop manipulator with 6 degrees-of-freedom and with enlarged workspace. It consists of two parts for minimizing the interference among actuators. One part is lower structure with planar 3 degrees-of-freedom and the other is upper one with spatial 3 degrees-of-freedom. Forward kinematics and inverse kinematics are solved, research about singularity points are carried out and workspace is evaluated. The comparison of workspace between Stewart platform, which is the typical parallel link manipulator, and the suggested manipulator shows that the workspace of the latter is wider than that of the former. Especially, simulation results also show that the suggested manipulator is more suitable when there needs rotation in the end-effector.