• Journal of Korean Institute of Industrial Engineers
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• v.25 no.3
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• pp.382-392
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• 1999

Industrial robots have increased in both the number and applications in today's material handling systems. However, traditional approaches to robot controling have had limited success in complicated environment, especially for real time applications. One of the main reasons for this is that most traditional methods use a set of kinematic equations to figure out the physical environment of the robot. In this paper, a neural network model to solve robot manipulator's inverse kinematics problem is suggested. It is composed of two Self-Organizing Feature Maps by which the workspace of robot environment and the joint space of robot manipulator is inter-linked to enable the learning of the inverse kinematic relationship between workspace and joint space. The proposed model has been simulated with two robot manipulators, one, consisting of 2 links in 2-dimensional workspace and the other, consisting of 3 links in 2-dimensional workspace, and the performance has been tested by accuracy of the manipulator's positioning and the response time.

• Transactions of the Korean Society of Mechanical Engineers
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• v.1 no.3
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• pp.125-130
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• 1977

This is a dimensionless analysis of interior ballistics for the design of gun tube. One of the characteristics of this analysis is to ues the .ETA.$_{j}$ number which means a relative quantity of virtual work to the kimetic energy of projectile at the muzzle. In order to apply the concept of virtual work, it is assumed that the projectile is moved from the beginning to the end of bore under constant pressure of the certain travel distance of projectile. The principle of the analysis is induced from the Le Duc equation, which expresses velocity as a function of projectile travel and is based on the translation of a hyperbolic curve. From this non-dimensional analysis, the optimum design parameters of pressure in the bore, velocity and acceleration of projectile can be obtained from the table of figure without computation. This method was verified by the experimental work.k.

• Fashion & Textile Research Journal
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• v.8 no.2
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• pp.209-213
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• 2006

The 3-D information is useful as basic data which has been utilized in the development of simulating technology as fit-simulation. The experiment is designed to take some useful data on the variant shapes which contribute in simulating the adaptability of the clothes. The general figure of the clothes are made after the figure of the basic standing posture of the human body. The shape of the clothes fits with kinetic characteristic of the human body as the form of the clothes gets twisted, the ease of the clothes changes, and the clothes itself expands. We studied the dressed shapes of blouse according to two types of the arm movement(basic posture and reach forward) and three types of clothes(foundation, blouse with short sleeves and sleeveless) in the sit-down-posture. We accomplished some experimental data on three-dimensional measurement of the dressing shapes using TDS-3100 3-D scanner made in Japan PULSTECH. It is considered that the variant of shapes and distribution of gaps in the dressed shapes of blouse are determined by the adaptability of clothes made in arm movement.

• Journal of the Korean GEO-environmental Society
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• v.11 no.4
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• pp.19-24
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• 2010

Generally, slope behavior is analyzed by 2-dimensional creep model. Creep behavior shows the deformation variation as time goes by without stress increment. Convention 2-dimensional creep analysis does not have the term of stress variation, it means creep analysis could not figure out the relationship of shear strength variation according to the stress variation and displacement. The slope weight and shear strength is directly related and interlocked to the safety variation and displacement of slope, therefore, this phenomenon could be treated and analyzed as combining the hysteresis and creep, the iteration of this process will result in the slope safety. Furthermore, the combined analysis will be the slope analysis considering shear stress, displacement and shear strength with time variation. In real case, because the variation of shear stress and strength happen at the same time, they should be changed into safety factor which is function of them. This paper shows the 3-dimensional variation of unit weight of soil with hybrid analysis considering creep and hysteresis on the seepage and drainage of rainfall, futhermore variations of shear stress and strength which make the safety factor change.

• Journal of Electrical Engineering and Technology
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• v.12 no.3
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• pp.1262-1270
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• 2017

Among various decoding algorithms of low-density parity-check (LDPC) codes, the min-sum (MS) algorithm and its modified algorithms are widely adopted because of their computational simplicity compared to the sum-product (SP) algorithm with slight loss of decoding performance. In the MS algorithm, the magnitude of the output message from a check node (CN) processing unit is decided by either the smallest or the next smallest input message which are denoted as min1 and min2, respectively. It has been shown that multiplying a scaling factor to the output of CN message will improve the decoding performance. Further, Zhong et al. have shown that multiplying different scaling factors (called a 2-dimensional scaling) to min1 and min2 much increases the performance of the LDPC decoder. In this paper, the simplified 2-dimensional scaled (S2DS) MS algorithm is proposed. In the proposed algorithm, we figure out a pair of the most efficient scaling factors which multiplications can be replaced with combinations of addition and shift operations. Furthermore, one scaling operation is approximated by the difference between min1 and min2. The simulation results show that S2DS achieves the error correcting performance which is close to or outperforms the SP algorithm regardless of coding rates, and its computational complexity is the lowest comparing to modified versions of MS algorithms.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.30 no.6
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• pp.345-348
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• 2017

In this work, static characteristics of 4H-SiC SJ-ACCUFETs were obtained by adjusting the p-pillar region. The structure of this SJ-ACCUFET was designed by using a two-dimensional simulator. The static characteristics of SJ-ACCUFET, such as the breakdown voltages, on-resistance, and figure of merits, were obtained by varying the p-pillar doping concentration from $1{\times}10^{15}cm^{-3}$ to $5{\times}10^{16}cm^{-3}$ and the thickness from $0{\mu}m$ to $9{\mu}m$. The doping concentration and the thickness of p-pillar region are closely related to the break down voltage and on-resistance and threshold voltages. Hence a silicon carbide SJ-ACCUFET structure with highly intensified breakdown voltages and low on-resistances with good figure of merits can be achieved by optimizing the p-pillar thickness and doping concentration.

• Journal of Technologic Dentistry
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• v.41 no.1
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• pp.21-27
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• 2019

Purpose: To evaluate 2D and 3D of occulsal, mesial-occlusal and mesial-occlusal-distal cavity of composite resin inlay. Methods: Abutment tooth 16, 36 of FDI system was selected for the study. Inlay prostheses classified as occlusal cavity (OC group), mesial-occlusal (MOC) and mesial-occlusal-distal cavity (MODC) were prepared using composite resin. Composite resin was injected with composite resin in prepared tooth cavity and then photopolymerized with UV light. Additional thermal polymerization was performed. Marginal gap of composite resin inlays were measured by digital microscope(x160) with silicone replica technique. The data was analyzed from statistical software for Kruskal-Wallis test (${\alpha}=0.05$). 3-dimensional analysis was analyzed through superimposition method. Results: The smallest 2D marginal fit measure of the three groups was $47.0{\pm}21.6{\mu}m$ in the MOC group. The largest 2D marginal was $69.1{\pm}33.8{\mu}m$ in the MODC group. In the trueness of the three groups, the most accurate figure was $14.4{\pm}2.3{\mu}m$ for the MODC group. In Precision, the most accurate figure was $14.5{\pm}4.3{\mu}m$ for the MODC group. Conclusion : In this study, 2D marginal fit of OC, MOC, and MODC cavities fabricated with composite resin was applicable to all clinical applications. In the 3D inner surface accuracy evaluation, the MODC group showed the accuracy results.

• Journal of the Korean Magnetics Society
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• v.10 no.3
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• pp.99-105
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• 2000

One dimensional magneto-photonic crystal having structure of (A/B)$^{k/W}$(B/A)$^{k}$ , where M is a magnetic layer of highly Bi-substituted iron garnet, A and B are dielectric layers of $SiO_2$ and T $a_2$O$_{5/}$, and k is the stacking number of the dielectric layers, has been numerically analyzed as a function of the thickness (d$_{M}$) of M (1∼535 nm) and the stacking numer of k (5∼15). The transmittance, Faraday rotation, and figure of merit of the magneto-photonic crystal have been investigated both in the visible and infrared wavelengths. A factor of several and several tens greater Faraday rotation and figure of merit have been obtained compared to the single layer of M, at many localized modes. In the visible the maximum figure of merit of 0.15 was obtained ( = 720 nm) when k = 11 and d$_{M}$ = 375 nm with T : 0.54, $\theta$$_{F}$ = 8.13$^{\circ}$, which was a factor of 30 greater than that of single garnet layer. Much greater maximum figure of merit, 0.285, was obtained in the infrared ( = 1114 nm) when k = 11 and d$_{M}$ = 800 nm with T = 0.66, $\theta$$_{F}$ = 18$^{\circ}$, which was a factor of 100 greater than that of single garnet layer.

• The Korean Journal of Urological Oncology
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• 제15권3호
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• pp.103-110
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• 2017

Cancer is the tissue complex consisted with heterogeneous cellular compositions, and microenvironmental cues. During the various stages of cancer initiation, development, and metastasis, cell-cell interactions as well as cell-extracellular matrix play major roles. Conventional cancer models both 2-dimensional and 3-dimensional (3D) present numerous limitations, which restrict their use as biomimetic models for drug screening and fundamental cancer biology studies. Recently, bioprinting biofabrication platform enables the creation of high-resolution 3D structures. Moreover this platform has been extensively used to model multiple organs and diseases, and this versatile technique has further found its creation of accurate models that figure out the complexity of the cancer microenvironment. In this review we will focus on cancer biology and limitations with current cancer models and we discuss vascular structures bioprinting that are critical to the construction of complex 3D cancer organoids. We finally conclude with current literature on bioprinting cancer models and propose future perspectives.

• Journal of the Korean GEO-environmental Society
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• v.16 no.12
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• pp.5-12
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• 2015

Since blasting noise is impact noise, it will give a sudden shock to the human. In the case, such as the blast vibration, it has given aging buildings and livestock great damage to move the vibration along ground in nearby regions. In this study, the influence of the blasting generated during excavation was analyzed for effects on regional. A couple of field and laboratory surveys about geological were carried out to figure out the geological ratio in the study-performed area. Blast vibration noise was compared to the domestic and abroad case studies and each of the institutions permissible standards established the most appropriate criteria in site condition. The vibration velocity of blasting vibration exploits the values which were measured from test blasting on the ground in order to examine blasting effect. Considering the blasting point as the shortest distance from safety facilities (farms, private houses, etc.), the examination of the influence range, which was derived from the vibration velocity of blasting vibration, was performed to figure out how the point affected the safety facilities. Three-dimensional numerical analysis was performed a time history analysis in order to analyze the behavior of the structure for a dynamic blast load, which was determined in three directions of the blast vibration value. The results of three-dimensional numerical analysis and the blasting effect of blasting vibration estimation equation blasting vibration of impact circle with accompanying test blasting were compared. And the analysis confirmed similar results figures.