• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.327-327
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• 2010

In this paper, an investigation of factors affecting piezoelectric transformers is presented by ATILA software. These transformers are multi-layer piezoelectric transformers in square shape $28\;{\times}\;28\;mm$ and operate in first vibration mode for step-down function. The piezoelectric transformers were modeled in 3D-dimension and analyzed using finite element method in ATILA software, a popular software in piezoelectric analysis. Modal and harmonic modules were used in this process. Effective factors to the properties of piezoelectric transformers including different input electrode patterns, directions of polarization, sizes of connective comer, number of layers were examined on the simulated model using input voltage of 20 V and load resistance of $100\;{\Omega}$. Moreover, thermal analysis was also obtained with conditions of input voltage of 5 V and no-load.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.19 no.3
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• pp.57-65
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• 2005

No matter how well the equally spaced grounding grid is designed, there we questions keep rising, such as leakage of current from comer conductor, high voltage of touch voltage in comers of grid than in center, and high material cost for grounding grid. The best-fitted design for unequally spaced grounding grid is a part that must be considered. Explain advantages of unequally spaced grounding grid and lead formula by dividing the number of grid division, j, into 20, instead of 7. Then, present Dij, which is optimum rate for unequally spaced grounding grid and verify safety and economy of the unequally spaced grounding grid by computer simulation with a poly-nominal function form.

• Journal of the Korean Society of Safety
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• v.22 no.6
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• pp.27-34
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• 2007

Static or dynamic elastomeric O-ring seals are installed between joining parts, and play key roles of high pressure-tightening. Sealing performance and structural safety of the O-ring are dependent on groove design, plain diameter, squeeze and applications such as pressure and temperature. In this study, to solve O-ring problem squeezed and highly pressurized under laterally one-sided constrained condition, hyperelastic FE analyses are performed, and FE results are compared with measured ones by computer-aided tomography, deformed shape and extrusion depth of the O-ring. Through the comparisons, FE analysis technique was verified. In order to evaluate design sensitivity, Taguchi method was used to select FE analysis cases. Adjustment parameters are clearance gap, groove comer radius, plain diameter and squeeze. By means of verified FE analysis technique, it has been analysed how the parameters have effects on contact stress fields, internal stress fields, and extrusion depths. Sealing performance has been evaluated based on contact stress fields and contact widths, and structural safety on internal stress and strain, extrusion lengths.

• Korean Journal of Remote Sensing
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• v.23 no.3
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• pp.211-219
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• 2007

Building extraction is one of the essential issues for 3D city modelling. In recent years, high-resolution satellite imagery has become widely available and it brings new methodology for urban mapping. In this paper, we have developed a semi-automatic algorithm to determine building heights from monoscopic high-resolution satellite data. The algorithm is based on the analysis of the projected shadow and actual shadow of a building. Once two roof comer points are measured manually, the algorithm detects (rectangular) roof boundary automatically. Then it estimates a building height automatically by projecting building shadow onto the image for a given building height, counting overlapping pixels between the projected shadow and actual shadow, and finding the height that maximizes the number of overlapping pixels. Once the height and roof boundary are available, the footprint and a 3D wireframe model of a building can be determined. The proposed algorithm is tested with IKONOS images over Deajeon city and the result is compared with the building height determined by stereo analysis. The accuracy of building height extraction is examined using standard error of estimate.

• Korean Institute of Interior Design Journal
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• v.17 no.5
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• pp.157-165
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• 2008

This study confirm the value and the importance of the human sensibility study to add up the new meaning, and to suggest a new value of Korean sensibility study through the understanding of current statusand trend of the sensibility study in the space. The method of the study was to collect date related to the sensibility study and to analyze it focusing on its details. The date was collected from researches published on the website since the establishment of Korean Institute of Interior Design and Architectural Institute of Korea and selected at the keyword search comer. The data was extracted under keywords of research object, research purpose, research method, and analysis method. And then it was quantified with HAYASH lll program and used for analyses according to its pattern and feature. The study shows that nowadays categories representing the current status and trend of the sensibility studies in space consist of the environment, the human, and the space. The contemporary study for sensibility puts the importance on a object and a subject of the study like the environment harmonized with human and space, the humans the subject that essentially uses the spate, and the space for the architecture and the interior that puts human in. Accordingly, the study for human sensibility should develop into the study for the design focused on the intangible relationship such as 'information', 'elements for space design', 'sensibility' beyond the existing tangible categories of environment, human, and space. In addition, in the method ways of study and analysis, those studies for the sensible relationship are required to develop into new types of study applying research methods of various studies beyond the traditional border between human studies, social science, and natural science.

• Journal of the Korean Institute of Intelligent Systems
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• v.18 no.2
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• pp.284-289
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• 2008

H.264/AVC among moving picture compression standard is the standard format for high compression rate and reliable video transimission. It generates blocking effects in video due to compressing video using block-based DCT and includes de-blocking filter to reduce blocking effect. Therefore, the filter makes the video over-smoothing and the quality of it is reduced. In this paper, we propose a improved de-blocking filter to solve the demerit. The proposed de-blocking filter redetermine the block boundary strength and apply the comer filtering to eliminate artifacts in low frequency domain. To evaluate the performance, we apply the proposed deblocking filter and exiting method to various video and evaluated the quality of image subjectively and objectively by analyzing the result. The simulation result shows the proposed method preserves the edge of video, reduces blocking effects and improves PSNR than the existing method.

• Research in Community and Public Health Nursing
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• v.12 no.1
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• pp.32-38
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• 2001

This study focused on the understanding the life of the elderly in the institution by phenomenological method. The participants were seven. who were 4 men and 3 women living in the elderly institution in Taegu. The data were collected through the indepth interviews and participant observation from June 20. 1999 to January 10. 2000 and analyzed by phenomenological analytic method by Giorgi. The structure of the meaning were as follows: Unhappy life: irresponsibility. self-centered thought. hardness. Irresistible life: misfortune. unhealthiness. Reading their son's intention. Bitter life: unfair treatment from their sons and daughters, betrayed feeling for their being thrown away. Outside oriented life: a fear of others' attention, wrong information about institutionalized life, maladjustment. Self-consolation life: comfortableness, convenience, economic merit of low cost. Dissatisfied life: discomfort from communal living. unkindness of the institution staffs, depreciated tendency to the elder people, irrational social security system. economic distress, physical pain, restrained feeling. Tenacity to their sons and daughters longingness for their sons and daughters, regretableness, waiting, Regretable life: remorse for their past life. agony, guilty, loneliness, grief, self-abandonment, self-depreciation, other residents' death in common. Inharmonious life with other residents complaint, conflict, ignorance, selfishness. Yearning life for opposite sex: sexual interest. Preparing for their life: control over their body and mind, consideration for others. A life with hope: blessing death, forever healthfulness, affiliation to their family. From the results of this study an education and consultation should be done as soon as possible to remove the negative recognition of the institutional life to the facility residents. the family and the future consumers of elderly institution. To minimize the maladjustment to facility life of residents, a new program and interventions for the new comer's are needed. The thesis with above results will widen the understandings of institutional residents and an important guidance for a better nursing care in elderly institutions of korea.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.22 no.1
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• pp.117-124
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• 2009

The p-convergent boundary element method has been proposed to analyze two-dimensional potential problem on the basis of high order Legendre shape functions that have different property comparing with the shape functions in conventional boundary element method. The location of nodes corresponding to high order shape function are not defined along the boundary, called by nodeless node, similar to the p-convergent finite element method. As the order of shape function increases, the collocation point method is used to solve linear simultaneous equations. The collocation patterns of p-convergent boundary element method consist of non-symmetric hierarchial or symmetric non-hierarchical. As the order of shape function increases, the number of collocation point increases. The singular integral that appears in p-convergent boundary element has been calculated by special numeric quadrature technique and semi-analytical integration technique. The L-shape domain problem including singularity in the vicinity of reentrant comer is analyzed and the numerical results show that the relative error is smaller than $10^{-2}%$ range as compared with other results in literatures. In case of same condition, the symmetric p-collocation point pattern shows high accuracy of solution.

• Journal of the Korean earth science society
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• v.29 no.2
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• pp.117-127
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• 2008

Source parameters for forty four earthquakes which occurred in and around the Korean Peninsula were determined and the relations between them were studied. Snoke's method (Snoke, 1987) was applied in determining the corner frequencies and seismic moments. In general, the source parameters estimated at different stations for an earthquake show different values. These disagreements have been interpreted as originating, in principle, from an inadequate consideration of the source radiation pattern and direction dependent attenuation and amplification. The comer frequencies and seismic moments were averaged to exclude the such directional effects. Other source parameters were estimated from the mean corner frequency and seismic moment. The static stress drops, determined in this study, tend to be independent of seismic moment for events greater than a specific magnitude. For earthquakes with a size less than about $1.0{\times}10^{22}$ dyne-cm (nearly same as $M_L = 4.0$), the stress drop tends to decrease with the decreasing moment. This fact suggests a breakdown of the scaling law of source parameters in earthquakes below the threshold magnitude.

• Transactions of Materials Processing
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• v.16 no.7
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• pp.530-537
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• 2007

This paper is concerned with the analysis of plastic deformation of bimetal co-extrusion process. Two sets of material combination have been adopted for analysis, i.e. combinations of Cu/Al and Fe/Al. In the first set of material combination, the selected materials are AA 1100 aluminum alloy as hard material and CDA 110 as soft one. This type of material selection is to examine the effect of hard core and soft sleeve and vice versa on the deformation pattern in terms of plastic zone and velocity discontinuity along the contact surface between construction materials. Four different cases of co-extrusion process in terms of material combination and interference bonding were simulated to investigate the effect of material arrangement between core and sleeve, and of bonding on the plastic zones and velocity discontinuity. In the other set of material combination, model materials used as core and sleeve were AA 1100 and AISI 1010, which are relatively soft and hard, respectively. Process parameters except diameter ratio of core to sleeve material such as semi-die angle, reduction in area in global sense and die comer radius have been set constant throughout the simulation to concentrate our effort on the analysis of influence of diameter ratio on deformation behavior such as deformation zone, surface expansion, exit velocity discontinuity between composite materials, and extrusion forces.