• Natural Product Sciences
• /
• v.4 no.2
• /
• pp.105-114
• /
• 1998

The antimutagenic activity of a methanol extract of Ecklonia stolonifera (Laminariaceae) against aflatoxin $B_1\;(AFB_1)$ was demonstrated with the Salmonella typhimurium assay. The numbers of revertants per plate decreased significantly when this extract was added to the assay system using S. Salmonella typhimurium TA100. The methanol extract also exhibited significant inhibitory effects on the micronuclei formation in mouse peripheral blood reticulocytes and the DNA damage in mouse spleen lymphocytes induced by N-methyl-N-nitrosourea (MMU) and benzo(a)pyrene (B(a)P). The MeOH extract was then sequentially partitioned with $CH_2Cl_2,\;CH_2Cl_2$ insoluble intermediate, EtOAc, n-BuOH, and $H_2O$. All fractions possessed antimutagenic activity but the $H_2O$ fraction was inactive. Among active fractions, the EtOAc and $CH_2Cl_2$ insoluble intermediate fractions showed the highest activity. Column chromatography using $SiO_2$ and Sephadex LH-20 yielded phloroglucinol from the EtOAc fraction. Phloroglucinol also demonstrated significant antimutagenic activity, and inhibitory effects on the micronuclei formation in mouse peripheral blood reticulocytes and DNA damage in mouse spleen lymphocytes induced by MMU and B(a)P.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.40 no.5
• /
• pp.461-466
• /
• 2012

This paper describes the development and test result of X-band Transmitter flight model(FM) of STSAT-3 by satellite research center(SaTReC), KAIST. The communication sub-system of STSAT-3 is consist of two different frequency band channels. S-band frequency is used for Telemetry & Command, and X-band frequency is used for mission data. Payload observations data in Mass Memory Unit (MMU) is modulated by QPSK modulator in X-band Transmitter, and then QPSK modulation signal is transmitted to antenna through transfer switch. In this Paper, we described the results of modulation, low-pass filter design, power amp development, and switch test. The FM XTU is delivered Spacecraft Assembly, Integration and Test(AIT) level through the completion of functional Test and environmental(vibration, thermal vacuum) Test successfully.

• Journal of the Institute of Electronics Engineers of Korea SC
• /
• v.45 no.4
• /
• pp.35-41
• /
• 2008

When memory devices are exposed to a space environment. they suffer various effects such as SEU(Single Event Upset). For these reasons, memory systems for space applications are generally equipped with error detection and correction(EDAC) logics against SEUs. In this paper, the error detection and correction strategy in the Mass Memory Unit(MMU) of the STSAT-3 is discussed. The probability equation of un-recoverable SEUs in the mass memory system is derived when the whole memory is encoded and decoded by the RS(10,8) Reed-Solomon code. Also the probability value is analyzed for various occurrence rates of SEUs which the STSAT-3 possibly suffers. The analyzed results can be used to determine the period of scrubbing the whole memory, which is one of the important parameters in the design of the MMU.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.20 no.2
• /
• pp.218-227
• /
• 2014

In this paper, it performed to the elastic-plastic large deflection series analysis using the experimental model and predicted a failure mode and ultimate strength. The collapse mode of numerical analysis model is formed a plastic hinge on loaded flange and consistent with the collapse mode of experimental model. Also, The yield line is formed in the web could observed that have occurred the crippling collapse mode and the ultimate loads of the experimental model and numerical analysis model have maintained linearly Means 1.07, Standard deviation 0.04, Coefficient of variation(COV) 0.04 and the result of ultimate loads have appeared approximately 8% error rate. it was found that very satisfied to the experimental results and the applied rules. if it is considered to be maintain a reasonable safety level, it is possible to predict the failure modes of aluminium alloy plate girders and ultimate loads.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2005.10a
• /
• pp.135-140
• /
• 2005

There are cofferdam and watertight wall to prevent of circulation or pollution during building of ocean structures like a dam and bridge in the harbors area and the sea. Inflow fluid and base of structure is important thing as one of the structural design factors for this interception wall like a cofferdam and watertight wall. In this study, it is revealed that at least 500 instantaneous velocity field data are required for ensemble average to get reliable turbulence statistics. The turbulent shear flow around a surface-mounted vertical wall was investigated by using the two-frame PIV(CACTUS 3.1) system and Mean velocity distributions have also been measured in the whole flow field.

• Proceedings of the IEEK Conference
• /
• 2000.06b
• /
• pp.226-229
• /
• 2000

In this paper, we describe implementation of 32-Bit RISC Core for portable communication/information equipment, such as cellular telephones and personal digital assistants, notebook, etc. The RISC core implements the ARM$\^$R/V4 instruction set on the basis of low power techniques in architecture level and logic level. It operates with 5-stage pipeline, and has harvard architecture to increase execution speed. The processor is modeled and simulated in RTL level using VHDL. Behavioral Cache and MMU are added to the VHDL model for instruction level verification of the processor. The core is implemented using Mentor P'||'&'||'R tools with IDEC C-631 Cell library of 0.6$\mu\textrm{m}$ CMOS 1-poly 3-metal CMOS technology.

• Proceedings of the IEEK Conference
• /
• 2004.06b
• /
• pp.399-402
• /
• 2004

This paper presents a system-on-chip prototype implementing a full integration for a portable digital audio system. The chip is composed of a audio processor block to implements audio decoding and voice compression or decompression software, a system control block including 8-bit MCU core and Memory Management Unit (MMU) a low power 16-bit ${\Sigma}{\Delta}$ CODEC, two DC-to-BC converter, and a flash memory controller. In order to support other audio algorithms except Mask ROM type's fixed codes, a novel 16-bit fixed-point DSP core with the program-download architecture is proposed. Funker, an efficient power management technique such as task-based clock management is implemented to reduce power consumption for portable application. The proposed chip has been fabricated with a 4 metal 0.25um CMOS technology and the chip area is about 7.1 mm ${\times}$ 7.1mm with 100mW power dissipation at 2.5V power supply.

• Proceedings of the KIEE Conference
• /
• 2004.11c
• /
• pp.394-396
• /
• 2004

CE 제품에 리얼타임 OS를 도입하면서, 제품의 조건을 만족시키기 위한 기술에 대해 많은 연구가 진행되고 있다. 특히, CE 제품에 있어서 중요한 이슈인 부팅 시간은 펌웨어수준과 비교했을 때 코드사이즈나 OS 초기화 과정 때문에 다소 느려지는 경향을 보이고 있다. 본 논문은 이러한 CE 제품의 부팅 시간에 초점을 맞추고 리얼타임 OS 적용시의 부팅 시간을 개선하였다. 구현에 사용된 ARM920T Core는 32-비트 RISC 구조이며, 각 16KB의 인스트럭션 Cache와 데이터 Cache, 그리고 MMU(Memory Management Unit)로 구성되어 있으며, 리얼타임 OS는 선점형 방식의 커널로 구성된 OS를 사용하였다.

• Proceedings of the KSRS Conference
• /
• 2003.11a
• /
• pp.1012-1014
• /
• 2003

Since it's establishment Malaysian Center for Remote Sensing (MACRES) has focused on the measurements from airborne and space borne remote sensors. In the year 1999 MACRES in collaboration with Multimedia University Malaysia (MMU) began developing it's own remote sensing sensors to meet Malaysian Remote Sensing needs. MACRES adopted a very systematic approached to the development of these microwave sensors. Starting from non-imaging ground base microwave remote sensing sensors MACRES is now well into developing it's first Airborne Synthetic Aperture Radar. With the capability of developing it's own sensors MACRES will profit more on the microwave remote sensing application research. This paper will demonstrate MACRES capability in developing Microwave Remote Sensing Sensors to meet Malaysian remote sensing society needs.

• Journal of Korea Multimedia Society
• /
• v.19 no.5
• /
• pp.881-889
• /
• 2016

Ocular region recently emerged as a new biometric trait for overcoming the limitations of iris recognition performance at the situation that cannot expect high user cooperation, because the acquisition of an ocular image does not require high user cooperation and close capture unlike an iris image. This study proposes a new method for ocular image recognition based on BRISK (binary robust invariant scalable keypoints). It uses the distance ratio of the two nearest neighbors to improve the accuracy of the detection of corresponding keypoint pairs, and it also uses geometric constraint for eliminating incorrect keypoint pairs. Experiments for evaluating the validity the proposed method were performed on MMU public database. The person recognition rate on left and right ocular image datasets showed 91.1% and 90.6% respectively. The performance represents about 5% higher accuracy than the SIFT-based method which has been widely used in a biometric field.