• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.2
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• pp.217-224
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• 2002

It is very important to measure and visualize the changes in the physical properties of fluid flow because this is the foundation of measurement techniques used in aerodynamics, heat transfer, plasma diagnostics, and stress analysis of transparent models. The optical methods are advantageous over probe-based techniques in the optical methods are of high speed, non-contact and are capable of providing full-field results with high spatial resolution. Therefore we propose the electronic speckle pattern interferometry(ESPI) that gives us a solution to overcome those limitations. In this paper the experimental results show qualitative and quantitative visualization of changes in the physical properties of the candle and alcohol lamp with 3D plotting. And we obtained the refractive index, mass density and temperature distribution of fluids. The results clearly show the process of flow phenomena and give the feasibility of quantitative interpretation of gasdynamics.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.23 no.9
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• pp.1172-1177
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• 1999

Comparisons of measured turbulence properties in the unburned gas region of turbulent premixed flame stabilized by pilot flame, in cases of combusting and non-combusting flow conditions, are presented. Methane-air premixed jet at fuel equivalence ratio of 0.6 and 1.0 and Reynolds number of 7,000 was diagnosed using two-color laser velocimeter to obtain turbulence statistics. Same set of measurements was repeated at 21 locations within the unburned gas region of both combusting and non-combusting conditions. Velocity data were analyzed to evaluate the spatial distribution of turbulence properties including Reynolds stress, probability densities, joint probability densities and auto correlations. Contrary to assumptions of current theoretical models, significant influence of flame was observed in every property that was studied in the present investigation. The effective viscosity increased ten-fold when flame was on from cold flow values. The effect of mixing on joint probability as well as in turbulence intensity was suppressed by the flame. The measurements suggest that common assumptions of premixed flame model may result in sizable error in prediction of flame length and temperature distribution in near-field.

• Journal of the Korean housing association
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• v.16 no.5
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• pp.75-81
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• 2005

The purpose of this study is to shed light on the field dynamics of 'lived space' in the light of our intuitive experiential contents by way of investigating three properties of space. While finding inspirations in the field theory of modern physics, investigation of our intuitive responses to the physical and spatial environment leads us to a coherent view of matter and space. We find then that our lived world is more than a system of inert matter; it is a dynamic environment of life in which feeling and mood, spiritual meaning and value, are perpetually infused with matter. Any concept of space, if it is to be meaningful to lift has to somehow acknowledge this fact. Empty space and matter cannot be conceived as mutually exclusive and independent as in classical physics. Rather they should be seen as two different manifestations of an underlying dynamism which permeates the world. The 'properties' of space can only be understood in terms of the 'impact' of material presence. The object cannot be seen as an isolated entity, but the 'conditioning' of its surrounding space has to be understood as an integral part of its being. Lived space can thus be viewed as an emotionally charged field, or a field of emotional energy, whose properties may be described in terms of concentration, mobility and resonance.

• Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
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• 2010.06a
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• pp.298-302
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• 2010

This study proposes a differential method to analyze the properties of the topographic surface driven from lidar imagery. Although airborne lidar imagery provides elevation information rapidly, a sequence of extraction processes are needed to acquire semantic information about objects such as terrain, roads, trees, vegetation, and buildings. For the processes, the properties present in a given lidar data need to be analyzed. In order to investigate the geometric characteristics of the surface, this study employs eigenvalues of the Hessian matrix. For experiments, a lidar image containing university campus buildings with the point density of about 1 meter was processed and the results show that the approach is effective to obtain the properties of each land object Surface.

• Architectural research
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• v.13 no.3
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• pp.19-29
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• 2011

Visibility of a space have been defined in several different ways: such as the axial line covering a convex space, a convex space defining the fattest shape in a space and an Isovist field formed by a field of vision at a given vantage point. Isovist fields are referred to as a descriptive medium to describe a movement by reviewing and analyzing geometric properties in them. Many descriptive methods for analysis of three-dimensional isovist are applied to analyzing the morphological properties in a 3D space more realistically. Although these models are regarded as a more advanced method for describing spatial properties, they have pros and cons such as complex mathematical calculations and somewhat arbitrary calibration in addition to huge consumption of memory space. These difficulties lead to the development of a three-dimensional visual accessibility model that explores the implication of building shape on the calculation of isovist fields drawn on a 2D plane. We propose a conceptual framework of how to measure the isovist field not as a 3D volume but as a combination of 2D plane on the ground with the 3D building shape of it's facade.

• Korean Institute of Interior Design Journal
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• no.22
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• pp.123-131
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• 2000

The purpose of this study is to propose a new design concept and properties within new paradigm. Contemporary students of architectural design seem to redefine the mechanic and reductive approach to design method based upon Euclidean geometry. In this study, the organic space-time and holistic view-point that constitutes the background for all this is radically different from the modern design. It consists of three sections as follow: First, it presents a concept of complex system and properties of complexity that we find in new natural science and tries to combine that news geometry with architectural design to provide a methodological basis for morphogenesis and transformation. Second, the complexity in architecture is defined as a fractal shape, folded space, and irreducible organic system that cannot be fully understood by modernist idea of architecture. Third, the complexity in architecture is strategy based on the electronic paradigm that would enable the emergence of creative possibility. The complexity theory offer new insights to explain not only natural laws but also define dynamic architecture. In fine, this study places a great emphasis on the organic world-view to the spatial organization, which I hope will contribute to generating a greater number of creative possibilities for design.

• Journal of the Korean Applied Science and Technology
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• v.12 no.2
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• pp.29-39
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• 1995

The phase separated structure and the electro-optical properties of the (polymer/liquid) crystal : LC) composite film strongly depended on the weight fraction of LC in it. The continuous LC phase was formed in a three-dimensional polymer network when the LC weight fraction was above 40wt%. The aggregation structure of the composite film could be controlled by controlling the solvent evaporation velocity during the film preparation process. The smaller LC domains or channels were formed in the case of the faster solvent evaporation velocity. The composite film exhibited reversible light scattering-light transmission switching upon electric field -OFF and -ON states, respectiverly. The light scattering properties of the composite film strongly depended on the spatial distortion of the nematic directors as well as the mismatch in refractive indices between matrix polymer and LC.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.18 no.2
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• pp.77-105
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• 2014

Medical imaging techniques have evolved to expand our ability to visualize new contrast information of electrical, optical, and mechanical properties of tissues in the human body using noninvasive measurement methods. In particular, electrical tissue property imaging techniques have received considerable attention for the last few decades since electrical properties of biological tissues and organs change with their physiological functions and pathological states. We can express the electrical tissue properties as the frequency-dependent admittivity, which can be measured in a macroscopic scale by assessing the relation between the time-harmonic electric field and current density. The main issue is to reconstruct spectroscopic admittivity images from 10 Hz to 1 MHz, for example, with reasonably high spatial and temporal resolutions. It requires a solution of a nonlinear inverse problem involving Maxwell's equations. To solve the inverse problem with practical significance, we need deep knowledge on its mathematical formulation of underlying physical phenomena, implementation of image reconstruction algorithms, and practical limitations associated with the measurement sensitivity, specificity, noise, and data acquisition time. This paper discusses a number of issues in electrical tissue property imaging modalities and their future directions.

• Journal of Korean Society for Geospatial Information Science
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• v.12 no.2 s.29
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• pp.37-42
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• 2004

The purpose of this study is not only preserving and restoring our nation's precious cultural inheritances transmitted for half millennia but informing the world of them. This study also aims recognizing the necessity of transmitting them to prosperity, constructing three-dimensional database by using a photogrammetry and VRML method and utilizing basic data of treasure exhibition with the progress of exhibition technique development on cyber space. Therefore, in this study, I suggest three dimensional modeling method that acquire three dimensional database about cultural properties through photogrammetry method which can acquire three-dimensional coordinates with easy and can express various color and stuff-feeling by using VRML.

• Nuclear Engineering and Technology
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• v.51 no.6
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• pp.1616-1625
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• 2019

Measuring occurrence times of random events, aimed to determine the statistical properties of the governing stochastic process, is a basic topic in science and engineering, and has been the subject of numerous mathematical modeling approaches. Often, true statistical properties deviate from measured properties due to the so called dead time phenomenon, where for a certain time period following detection, the detection system is not operational. Understanding the dead time effect is especially important in radiation measurements, often characterized by high count rates and a non-reducible detector dead time (originating in the physics of particle detection). The effect of dead time can be interpreted as a suitable rarefied sequence of the original time sequence. This paper provides a limit theorem for a high rate (diffusion-scale) counter with extendable (Type II) dead time, where the underlying counting process is a renewal process with finite second moment for the inter-event distribution. The results are very general, in the sense that they refer to a general inter arrival time and a random dead time with general distribution. Following the theoretical results, we will demonstrate the applicability of the results in three applications: serially connected components, multiplicity counting and measurements of aerosol spatial distribution.