• Composites Research
• /
• v.24 no.4
• /
• pp.41-47
• /
• 2011

This paper deals with anisotropic property and structural analysis for short fiber reinforced plastic composites manufactured by the injection molding process. The common approach for modeling this type of material is the consideration of the material as homogenous and isotropic. However, the common isotropy approach often results in unexpected failure. To overcome this, new structure analysis methodology was developed in order to consider fiber orientation effect using injection mold flow analysis and Halpin-Tsai equations for unidirectional composites and taking an orientation average. The numerical predictions are compared to experimental data for tensile specimen. The predicted mechanical properties agree well with experimental data for fiber orientation and weld line effect. The analysis system was also applied to an automobile part. The proposed anisotropic model predicted different mechanical properties by position of the part and different mechanical performance of the part was changed according to injection gate position.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.44 no.7 s.361
• /
• pp.45-53
• /
• 2007

In this paper, we propose an efficient hardware architecture for H.264/AVC CAVLC (Context-based Adaptive Variable Length Coding) encoding. Previous CAVLC architectures search all of the coefficients to find statistic characteristics in a block. However, it is unnecessary information that zero coefficients following the last position of a non-zero coefficient when CAVLC encodes residual coefficients. In order to reduce this unnecessary operation, we propose two techniques, which detect the first and last position of non-zero coefficients and arrange non-zero coefficients sequentially. By adopting these two techniques, the required processing time was reduced about 23% compared with previous architecture. It was designed in a hardware description language and total logic gate count is 16.3k using 0.18um standard cell library Simulation results show that our design is capable of real-time processing for $1920{\times}1088\;30fps$ videos at 81MHz.

• 제어로봇시스템학회:학술대회논문집
• /
• 2003.10a
• /
• pp.1022-1027
• /
• 2003

The Motion controllers provide the sophisticated performance and enhanced capabilities we can see in the movements of robotic systems. Several types of motion controllers are available, some based on the kind of overall control system in use. PLC (Programmable Logic Controller)-based motion controllers still predominate. The many peoples use MCU (Micro Controller Unit)-based board level motion controllers and will continue to in the near-term future. These motion controllers control a variety motor system like robotic systems. Generally, They consist of large and complex circuits. PLC-based motion controller consists of high performance PLC, development tool, and application specific software. It can be cause to generate several problems that are large size and space, much cabling, and additional high coasts. MCU-based motion controller consists of memories like ROM and RAM, I/O interface ports, and decoder in order to operate MCU. Additionally, it needs DPRAM to communicate with host PC, counter to get position information of motor by using encoder signal, additional circuits to control servo, and application specific software to generate a various velocity profiles. It can be causes to generate several problems that are overall system complexity, large size and space, much cabling, large power consumption and additional high costs. Also, it needs much times to calculate velocity profile because of generating by software method and don't generate various velocity profiles like arbitrary velocity profile. Therefore, It is hard to generate expected various velocity profiles. And further, to embed real-time OS (Operating System) is considered for more reliable motion control. In this paper, the structure of chip-based precision motion controller is proposed to solve above-mentioned problems of control systems. This proposed motion controller is designed with a FPGA (Field Programmable Gate Arrays) by using the VHDL (Very high speed integrated circuit Hardware Description Language) and Handel-C that is program language for deign hardware. This motion controller consists of Velocity Profile Generator (VPG) part to generate expected various velocity profiles, PCI Interface part to communicate with host PC, Feedback Counter part to get position information by using encoder signal, Clock Generator to generate expected various clock signal, Controller part to control position of motor with generated velocity profile and position information, and Data Converter part to convert and transmit compatible data to D/A converter.

• Journal of Biomedical Engineering Research
• /
• v.20 no.1
• /
• pp.107-113
• /
• 1999

The purpose of this study was to develop a miniature imaging gamma probe with high performance that can detect small or residual tumors after surgery. Gamma probe detector system consists of NaI(Tl) scintillator, position sensitive photomultiplier tube (PSPMT), and collimator. PSPMT was optically coupled with 6.5 mm thick, 7.62 cm diameter of NaI(Tl) crystal and supplied with -1000V for high voltage. Parallel hexagonal hole collimator was manufactured for characteristics of 40-mm hole length, 1.3-mm hole diameter, and 0.22 mm septal thickness. Electronics consist of position and trigger signal readout systems. Position signals were obtained with summing, subtracting, and dividing circuit using preamplifer and amplifier. Trigger signals were obtained using summing amplifier, constant fraction discriminator, and gate and delay generator module with preamplifer. Data acquisition and processing were performed by Gamma-PF interface board inserted into pentium PC and PIP software. For imaging studies, flood and slit mask images were acquired using a point source. Two hole phantom images were also acquired with collimator. Intrinsic and system spatial resolutions were measured as 3.97 mm and 5.97 mm, respectively. In conclusion, Miniature gamma probe images based on the PSPMT showed good image quality, we conclude that the miniature imaging gamma probe was successfully developed and good image data were obtained. However, further studies will be required to optimize imaging characteristics.

• Proceedings of the IEEK Conference
• /
• 2004.06b
• /
• pp.493-496
• /
• 2004

Recently, organic thin films are widely used to the application of organic optoelectronic devices such as OLED, OTFT, organic solar cell, and organic laser, etc. The electrical transport of organic thin film is very important to determine the performance and thus should be analyzed for analysis of operation and design of devices. However, there have been rarely known about the electrical transport of organic thin films. As an example pentacene is known to be a good organic semiconductor to produce the best performance in OTFT at the present. But the performance is varied depending on the position of source/drain contacts and gate surface states and the thickness of thin film. Therefore, it is necessary to investigate the effects of the above-mentioned factors on the electrical properties of pentacene thin film.

• JSTS:Journal of Semiconductor Technology and Science
• /
• v.16 no.2
• /
• pp.185-190
• /
• 2016

A 70-${\AA}$ nanowire field-effect transistor (FET) for sub-10-nm CMOS technology is designed and simulated in order to investigate the impact of an oxide trap on random telegraph noise (RTN) in the device. It is observed that the drain current fluctuation (${\Delta}I_D/I_D$) increases up to a maximum of 78 % due to the single electron trapping. In addition, the effect of various trap positions on the RTN in the nanowire FET is thoroughly analyzed at various drain and gate voltages. As the drain voltage increases, the peak point for the ${\Delta}I_D/I_D$ shifts toward the source side. The distortion in the electron carrier density and the conduction band energy when the trap is filled with an electron at various positions in the device supports these results.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.23 no.9
• /
• pp.124-129
• /
• 2009

Recently, PWM inverter is widely utilized for many industrial applications such as high performance drive and space vector pulse width modulation(SVPWM) inverter which has high voltage ratio and low harmonics compared to conventional PWM inverter. This paper presents the implementation on a field programmable gate array(FPGA) of a SVPWM module for a voltage source inverter. The SVPWM module consists of PWM generator, current and position sensor interface and dead time compensator. The implemented SVPWM module can be integrated with a digital signal processor(DSP) to provide a flexible and effective solution for high performance voltage source inverter and for the use of multi-motor control. The performance of SVPWM module is verified by simulation and several experimental results.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.11 no.2
• /
• pp.127-134
• /
• 2006

This paper describes a fully hardware realization of vector controller for the permanent magnet synchronous motor (PMSM) using high density field programmable gate mays (FPGA). In the proposed system, the vector controller including vector transformation , PI regulator, position and speed measurement, current measurement, and space vector PWM blocks is implemented in a FPGA using a VHSIC hardware description language (VHDL). The experimental results using a 1.1kW PMSM are provided to show the validity of the proposed system.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.12 no.3
• /
• pp.7-12
• /
• 2013

In Die casting process, the problem of die degradation is often issued. In oder to increase of die life the material degradation of die steel was investigated using test core pins. Three test core pins were positioned in front of the gate entry and observed washout and soldering resistance during Mg die casting process. The test parameters are set as different commercial die materials, coatings condition and hardness of die surface. Usign 220t magnesium die casting machine was employed to cast AZ91 magnesium alloys. After 150 shots, macroscopic observation of die surface was carried out. Additional 50 cycles later, test pins were chemically cleaned with 5% HCl aqueous solution to find out the existence of washout and soldering layers. Microstructural characterization of die surface and the die roughness measurement were performed together. Computational simulation using AnyCasting program was also beneficial to correlate the extent of die damage with the position of test pin inside die cavity. As results, the optimal combination of die steel with productive coating as well as its hardness was drawn out. it will be helpful to decide the material and condition considering increasing of tool life.

• Journal of Korean Medical classics
• /
• v.13 no.2 s.17
• /
• pp.85-85
• /
• 2000

Following is the result through translating. studying, and analyzing 『San Zhi Shan(三指禪)』, the book worked by Zhou Xue Ting(周學霆). 1. The chapter of 『Mai Xue Yuan Liu(脈學源流)』 explains thc Xiang Shu Xue(象數學) viewpoint, the part that pulse is based on Lu guan(律管). 2. The chapter of 『Liu Bu Mai Jie(六部脈解)』 explains that emphasizing Shen(神) through understanding the shape of pulse(脈象) is more important than the locating the area of thc shape of pulse(脈象). 3. The chapter of 『Zuo Xin Tan Zhong Can Dan Shen Xiao Chang You Fei Xiang Zhong Pi Wei Ming Da Chang Bian($좌심단중간담신소장{\cdot}우폐흉중비위명대장판$)』exhibits the different view about the position of pulse from Li Shi Zhen(李時珍)'s. the chapter in which Zhou(周) arranges Heart{\cdot}Small\;Intestine{\cdot}Liver{\cdot}Gall\;Bladder{\cdot}Kidneys{\cdot}and$ Bladcler($心{\cdot}小腸{\cdot}肝{\cdot}膽{\cdot}腎{\cdot}膀胱$) in left hand and $Lungs{\cdot}Large{\cdot}Intestine{\cdot}Spleen{\cdot}Stomach{\cdot}Kidney{\cdot}and$ The gate of Vitality($肺{\cdot}大腸{\cdot}脾{\cdot}胃{\cdot}腎{\cdot}命門$) in right hand. From the above results, I'm sure that 『San Zhi Shan(三指禪)』which has headed down to descendants as the special book about the study of pulse has developed the theory of pulse. Therefore I expect that the more profound study about this will be going on.