• Journal of the Korean Magnetics Society
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• v.13 no.1
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• pp.36-40
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• 2003

We have grown D $y_{x}$B $i_{3-x}$F $e_{5}$ $O_{12}$ (x = 0.5,1.0, 1.5,2.0) magnetic garnet thin films upon $Al_2$O3i and GGG substrate using Pechini process. The annealing temperature to get single phase D $y_{x}$B $i_{3-x}$F $e_{5}$ $O_{12}$ garnet is dependent on substrate, i.e. the annealing temperature for GGG substrate il 5$0^{\circ}C$ lower than that for $Al_2$ $O_3$ substrate. The grains of garnet thin film grown on GGG (111) plane align along [111] direction, and in this case the hysteresis curve does not saturate up to H : 5000 Oe. We attribute this phenomenon to rotation magnetization process. The maximum amount of Bi substitution in polycrystalline D $y_{x}$B $i_{3-x}$F $e_{5}$ $O_{12}$ thin film prepared by Pechini process is restricted to 2.0 Bi atom/unit cell, and this value is less than that in single garnet crystall grown by LPE method.own by LPE method.ethod.

• The Journal of the Korea Contents Association
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• v.5 no.4
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• pp.133-140
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• 2005

Culture Technology is the basic technology which produces cultural contents in a narrow sense. All nations do their best in order to create new contents which can form international and cultural sympathy. If a variety of contents are created by applying Korean proper cultural heritages, they will be creative and competitive internationally. Therefore, technology of original cultural restoration is an essential and crucial skill. In this paper, 'gilt bronze dragon-phoenix ring-pommeled sword', a cultural heritage of baekje age, will be restored to the original form digitally on the basis of three-dimensional shape-information processing technology and the scientifically analyzed data. First of all, data from three-dimensional scanning is revised using stuffing and smoothing methods after sampling, extracting characteristics, and align. Then, they are modeled in a curved surface with NURBS and B-Spline. Secondly, textures are edited by estimating the color of components and the quality of materials, and then they are mapped. Original form model which was made was revised and corrected by specialists' examinations. The digitally revised ring-pommeled sword was combined with information technology, and it can be used to revise damaged cultural heritages by constructing formal database of ring-pommeled sword with regard to age, area and type. It can be also used as educational contents in archaeology or preservation science and cultural contents such as movies, broadcasts, games, animations and so on.

• Proceedings of the IEEK Conference
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• 2005.11a
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• pp.679-682
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• 2005

Negative-differential conductance (NDC) characteristics as well as negative-differential trans-conductance (NDT) characteristics have been observed in the room temperature I-V characteristics of Field-induced Inter-band Tunneling Effect Transistors (FITETs). These characteristics have been explained with inter-band tunneling physics, from which, inter-band tunneling current flows when the energy bands of degenerately doped regions align, and it does not flow when they don't. FITET is an SOI device and the body region is not directly connected to the external terminal. Therefore, Fermi energy in the body region is determined by electrical coupling among four regions - gate, source, drain and substrate. So, a quasi Fermi energy of the majority carriers in the floating body region can be changed by external voltages, and this causes the energy band movements in the body region, which determine whether the energy bands between degenerately doped junctions aligns or not. This is a key point for an explanation of NDT and NDC characteristics. In this paper, a quasi Fermi energy movement in the floating body region of FITET was investigated by a device simulation. This result was applied for the description of relation between quasi Fermi energy in the body region and external gate bias voltage.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.43 no.2 s.308
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• pp.30-39
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• 2006

Iris recognition is that identifies a user based on the unique iris texture patterns which has the functionalities of dilating or contracting pupil region. Iris recognition systems extract the iris pattern in iris image captured by iris recognition camera. Therefore performance of iris recognition is affected by the quality of iris image which includes iris pattern. If iris image is blurred, iris pattern is transformed. It causes FRR(False Rejection Error) to be increased. Optical defocusing is the main factor to make blurred iris images. In conventional iris recognition camera, they use two kinds of focusing methods such as lilted and auto-focusing method. In case of fixed focusing method, the users should repeatedly align their eyes in DOF(Depth of Field), while the iris recognition system acquires good focused is image. Therefore it can give much inconvenience to the users. In case of auto-focusing method, the iris recognition camera moves focus lens with auto-focusing algorithm for capturing the best focused image. However, that needs additional H/W equipment such as distance measuring sensor between users and camera lens, and motor to move focus lens. Therefore the size and cost of iris recognition camera are increased and this kind of camera cannot be used for small sized mobile device. To overcome those problems, we propose method to increase DOF by iris image restoration algorithm based on focus value of iris image. When we tested our proposed algorithm with BM-ET100 made by Panasonic, we could increase operation range from 48-53cm to 46-56cm.

• Korean Journal of Cleft Lip And Palate
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• v.2 no.1_2
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• pp.29-41
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• 1999

Cleft lip and palate is the most frequent congenital facial deformity of the orofacial area. Successful management of patients with cleft lip / palate requires a multidiciplinary approach from birth to adult stage. Coordinated treatment by the cleft palate team is an essential requirement to obtain optimum treatment results. One of the negative effect of the early surgical interventions of lip and palate is a significant incidence of maxillary growth restriction that produces secondary deformities of the jaws and malocclusion that includes congenital missing of lateral incisor, malformed teeth, rotation or ectopic position of upper anterior teeth, and it has been thought due to the resistance of palatal scar tissue. In Orthodontic treatment for cleft lip / palate patients, expansion of upper dental arch or palatal suture is often needed to correct posterior and/or anterior cross bite and align upper teeth. Various appliances such as hyrax, quad-helix, fan-type expansion screw and jointed-fan type expander can be used for palatal expansion. In the orthodontic treatment of the cleft lip / palate patient, we must consider patient age and severity of palatal constriction for proper appliance selection, and must pay special attention to maintain the treatment results.

• Archives of design research
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• v.17 no.2
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• pp.279-288
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• 2004

Corporate design activities have expanded from being exclusive and passive responsibilities to active participation in planning, marketing, technology and corporate brand image differentiation for successful business. Thus the communications between designers and other functions come to include critical decision making, information sharing, and objective reasoning. Given that design activities now have to involve various functions in product development, the styling-related design process, which is still developed by designer's intuition and experience, poses as an obstacle not just between various functions involved, but even within the design function. To overcome this obstacle and to lead more effective design decision process, a means for product form development assessment and management is necessary. This research proposes a foundation for managing and assessing product form based on the hypothesis and demonstration of discovering a system of formative factor and order a product form expresses that can be shared as an objective and logical system. As a result of this demonstration, the form as a unique visual expression and the factors related to the form and its co-relationship are examined. The factors are called formative parameters and the system is named as the product form alignment method. Based on the logic derived from the system, the process for developing an image that aligns with the predefined goal is explained. The method defines a balance between a designer's intuitive creativity and the extracted logic, which can act as a basis for designers to share design language among themselves and for communication between design and other functions. Based on this system, designers are able to align design work with the set goal, and focus and limit the range of form development, which is anticipated to result in lead-time reduction and minimizing unnecessary obstacles and mistakes.

• Journal of the Korean Society of Radiology
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• v.12 no.5
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• pp.699-706
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• 2018

In this study, we measured signal intensities according to array coil position changes to provide reference data of coil directions and the distances as it deters image quality unless the coils are aligned properly. The multi-purpose MRI phantom was placed in body array coils, and it was moved to the top, bottom, left, and right directions by 2 cm from the center to 10 cm. After obtaining images, signal intensities were measured and compared. The results of this study were as follows: Except for the upward direction, the signal intensities of the reference signal was not significantly different from that of the reference signal intensity within 2cm in both T1 and T2-weighted images. In conclusion, in clinical circumstances which various challenges exist to align the coils exactly on the same lines, array coils should be positioned at least within 2 cm from the center except for the upward direction, on the same line to prevent the image qualities are lowered.

• Polymer(Korea)
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• v.30 no.4
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• pp.362-366
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• 2006

It was found by polarized FTIR spectroscopic studies that pentacene molecules are arranged with their molecular axes perpendicular to the substrate surface when pentacene films are deposited on a polyimide alignment layer. The ring plane in a pentacene molecule is arranged parallel to the rubbing direction of the polyimide alignment film while no specific arrangement of vertically deposited pentacene molecules was found for the film without rubbing. The pentacene band at $1296cm^{-1}$ which has a transition dipole moment parallel to the ring plane is much stronger in a polarized IR spectrum of parallel to the rubbing direction, whereas the band at $908cm^{-1}$ whose transition dipole align normal to the ring plane shows much stronger intensity in a spectrum of perpendicular to the rubbing direction. These findings indicate that orientation of polyimide chains affects the arrangement of pentacene molecules when they are deposited on a polyimide alignment film.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.5
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• pp.635-643
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• 2018

This paper propose a method to identify the motor parameters and improve input voltage error which affect the low speed position error of the back-emf(back electromotive force) based sensorless algorithm and to secure the operation reliability and stability even in the case where the load fluctuation is severe and the start and low speed operation frequently occurs. In the model-based observer used in this paper, stator resistance, inductance, and input voltage are particularly influential factors on low speed performance. Stator resistance can cause resistance value fluctuation which may occur in mass production process, and fluctuation of resistance value due to heat generated during operation. The inductance is influenced by the fluctuation due to the manufacturing dispersion and at a low speed where the change of the current is severe. In order to find stator resistance and inductance which have different initial values and fluctuate during operation and have a large influence on sensorless performance at low speed, they are commonly measured through 2-point calculation method by 2-step align current injection. The effect of voltage error is minimized by offsetting the voltage error. In addition, when the command voltage is used, it is difficult to estimate the back-emf due to the relatively large distortion voltage due to the dead time and the voltage drop of the power device. In this paper, we propose a simple circuit and method to detect the voltage by measuring the PWM(Pulse Width Modulation) pulse width and compensate the voltage drop of the power device with the table, thereby minimizing the position error due to the exact estimation of the back-emf at low speed. The suitability of the proposed algorithm is verified through experiment.

• Journal of Microbiology and Biotechnology
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• v.13 no.6
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• pp.841-845
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• 2003

In order for engineered tissues to find clinical utility, the engineered tissues must function appropriately. However, smooth muscle (SM) tissues engineered in vitro with a conventional tissue engineering technique may not exhibit contractile functions, because smooth muscle cells (SMCs) cultured in vitro typically revert from a contractile, differentiated phenotype to a synthetic, nondifferentiated phenotype and lose their ability to contract. SMCs in vivo typically reside in mechanically dynamic environments. We hypothesized that cyclic mechanical stretch induces the features of SMCs in in vitro engineered tissues to be similar to those of SMCs in native tissues. To test the hypothesis, aortic SMCs were seeded onto elastic, three-dimensional scaffolds and cultured in vitro under a cyclic mechanical stretching condition for 4 weeks. A significant cell alignment in a direction parallel to the cyclic stretching direction was found in the SM tissues exposed to cyclic stretching. The cellular alignment and alignment direction were consistent with those of native vascular SM tissues, in which SMCs in vivo align in the radial direction (parallel to stretching direction). In control tissues (SM tissues engineered without stretching), cells randomly aligned. The expression of SM ${\alpha}-actin$ and SM myosin heavy chain, phenotypic markers of SMCs in a contractile state, was upregulated in the stretched tissues by 2.5- and 2.0-fold, respectively, compared to SMCs in the control tissues. The cellular features of alignment and contractile phenotype of SMCs in the SM tissues engineered under a mechanically dynamic environment could allow the engineered SM tissues to exhibit contractile functions.