• Natural Product Sciences
• /
• 제22권3호
• /
• pp.201-208
• /
• 2016

Here in this study, we investigated the lifespan-extending effect and underlying mechanism of methanolic extract of Moringa olelifa leaves (MML) using Caenorhabditis elegans (C. elegans) model system. To define the longevity properties of MML we conducted lifespan assay and MML showed significant increase in lifespan under normal culture condition. In addition, MML elevated stress tolerance of C. elegans to endure against thermal, oxidative and osmotic stress conditions. Our data also revealed that increased activities of antioxidant enzymes and expressions of stress resistance proteins were attributed to MML-mediated enhanced stress resistance. We further investigated the involvement of MML on the aging-related factors such as growth, food intake, fertility, and motility. Interestingly, MML significantly reduced growth and egg-laying, suggesting these factors were closely linked with MML-mediated longevity. We also observed the movement of aged worms to estimate the effects of MML on the health span. Herein, MML efficiently elevated motility of aged worms, indicating MML may affect health span as well as lifespan. Our genetic analysis using knockout mutants showed that lifespan-extension activity of MML was interconnected with several genes such as skn-1, sir-2.1, daf-2, age-1 and daf-16. Based on these results, we could conclude that MML prolongs the lifespan of worms via activation of SKN-1 and SIR-2.1 and inhibition of insulin/IGF pathway, followed by DAF-16 activation.

• 대한전자공학회:학술대회논문집
• /
• 대한전자공학회 1998년도 하계종합학술대회논문집
• /
• pp.855-858
• /
• 1998

본 연구에서는 MML(merged memory logic)구조를 갖는 스캔라인 컨버터를 설계하여 제안한다. 비월주사 방식인 TV 비디오 신호를 FIFO 메모리에 저장하여 순차주사방식인 VGA 비디오 시모호 변환하는 주사선 변환기를 MML 개념으로 설계하였다. MML 회로는 VHDL로 설계하여 V-system으로 시뮬레이션을 수행하고 altera FPGA에 구현한 후, TV 비디오 신호를 PC 모니터로 보기 위한 외장형 tV 수신 시스템에 적용하여 성능을 검증했다. MML 개념으로 설계된 컨버터는 system-on-a-chip 설계의 첫 단계로 메모리와 로직부분으로 구성된 일반적인 컨버터보다 효율적인 시스템 설계를 할 수 있다.

• 한국통신학회논문지
• /
• 제31권11A호
• /
• pp.1167-1175
• /
• 2006

ML-DFE(Maximum Likelihood-Decision Feedback Equalization) 기법은 V-BLAST와 같은 공간다중화 MIMO시스템에서 ML 기법의 구현 복잡도를 줄이기 위한 준 최적 신호검출기법으로 불 수 있다. ML-DFE 기법은 ML 기법과 DFE 기법을 결합하여 오차전파를 줄이면서 rich scattering 환경에서 높은 다이버시티 이득을 얻을 수 있다. 본 논문에서는 ML-DFE 기법과 동일한 성능을 보이면서 연산복잡도를 줄일 수 있는 MML-DFE(Modified Maximum Likelihood - Decision Feedback Equalization) 기법을 제안한다. 또한 FPGA 구현을 통하여 제안된 MML-DFE 기법이 기존 ML-DFE 기법에 비하여 구현복잡도를 크게 감소시키면서 동일한 성능을 유지함을 확인한다.

• 대한전자공학회:학술대회논문집
• /
• 대한전자공학회 1998년도 추계종합학술대회 논문집
• /
• pp.695-698
• /
• 1998

Today SOC(system on a chip) is a trend in VLSI design society. Especially MML(merged memory Logic) process provides designers with good chances to implement SOC which is consists of DRAM, SRAM, Logic and A/D mixed mode ciruit blocks. Designers need good circuit library which is reliable and easy to tune for specific design. For this need we present semi-automated analog compiler methodology. And we aplied this design methodology to resistor-string DAC design.

• Tribology and Lubricants
• /
• 제25권1호
• /
• pp.66-72
• /
• 2009

Al-based composites reinforced with SiC particulate were fabricated using a thermal spray process, and dry sliding wear behavior of the composites was investigated. Pre-mixed Al and SiC powders were sprayed on an A16061 substrate by flame spraying, and dry sliding wear test were performed under various sliding speed and applied load conditions against ${Al_2}{O_3}$ ball. Wear behavior of the composites was studied by using scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDX) and X-ray diffraction (XRD). And build-up mechanism of MML on the worn surface of the composites was examined. It was revealed that these MML was formed of debris from the contact surface of the composites and effected to wear behavior of the composites protecting the contact surface of the composites.

• JSTS:Journal of Semiconductor Technology and Science
• /
• 제4권4호
• /
• pp.293-299
• /
• 2004

An active RC 2nd order Butterworth filter suitable for a baseband channel-selection filter of a direct conversion receiver is presented. The linearity of the 2nd order Butterworth filter is analyzed. In order to improve the linearity of the filter, the operational amplifiers should have a high linear gain and low 3rd harmonic, and the filter should be designed to have large feedback factor. This second order Butterworth filter achieves-14dBV in-channel (400kHz, 500kHz) IIP3, +29dBV out-channel (10MHz, 20.2MHz) IIP3 and 15.6 $nV/\sqrt{Hz}$ input-referred noise and dissipates 10.8mW from a 2.7-V supply. The analysis and experimental results are in good agreement

• ETRI Journal
• /
• 제27권6호
• /
• pp.747-758
• /
• 2005

The problem of selection among competing models has been a fundamental issue in statistical data analysis. Good fits to data can be misleading since they can result from properties of the model that have nothing to do with it being a close approximation to the source distribution of interest (for example, overfitting). In this study we focus on the preference among models from a family of polynomial regressors. Three decades of research has spawned a number of plausible techniques for the selection of models, namely, Akaike's Finite Prediction Error (FPE) and Information Criterion (AIC), Schwartz's criterion (SCH), Generalized Cross Validation (GCV), Wallace's Minimum Message Length (MML), Minimum Description Length (MDL), and Vapnik's Structural Risk Minimization (SRM). The fundamental similarity between all these principles is their attempt to define an appropriate balance between the complexity of models and their ability to explain the data. This paper presents an empirical study of the above principles in the context of model selection, where the models under consideration are univariate polynomials. The paper includes a detailed empirical evaluation of the model selection methods on six target functions, with varying sample sizes and added Gaussian noise. The results from the study appear to provide strong evidence in support of the MML- and SRM- based methods over the other standard approaches (FPE, AIC, SCH and GCV).

• 한국통신학회논문지
• /
• 제33권2A호
• /
• pp.121-129
• /
• 2008

본 논문은 ECMA(European Computer Manufacturers Association)의 표준인 MB-OFDM (MultiBand-Orthogonal Frequency Division Multiplexing) UWB(Ultra Wide-Band) 시스템에서 SISO(Single Input Single Output) 성능을 유지하면서 데이터 전송률을 2배로 올리기 위한 공간 다중화 MIMO(Multiple Input Multiple Output) 수신기 구조의 성능을 비교, 분석하였다. 이를 위해 송신단은2개의 안테나를 가지는 수평 부호화 방식과 대각 부호화 방식을 사용하였으며 수신단은 2, 3개 안테나에 대한 다양한 공간다중화 수신기 방식을 고려하였다. 다양한 공간 다중화 수신단 구조의 연산 복잡도 비교와 전산 모의 실험을 통해 $2{\times}2$ 구조의 MML 방법 또는 $\2{times}3$ 구조의 ZF 방법이 SISO 성능을 열화시키지 않고 전송률을 높이는 MIMO MB-OFDM의 간단한 수신단 구조임을 확인하였다.

• The Journal of the Acoustical Society of Korea
• /
• 제20권1E호
• /
• pp.14-19
• /
• 2001

We have proposed BIST method and circuit for embedded 16M SDRAM with logic. It can test the AC parameter of embedded 16M SDRAM using the BIST circuit capable of detecting the address of a fail cell installed in an Merged Memory with Logic(MML). It generates the information of repair for redundancy circuit. The function and AC parameter of the embedded memory can also be tested using the proposed BIST method. It is possible to test the embedded SDRAM without external test pin. The total gate of the BIST circuit is approximately 4,500 in the case of synthesizing by 0.25μm cell library and is verified by Verilog simulation. The test time of each one AC parameter is about 200ms using 2Y-March 14n algorithm.

• 동력기계공학회지
• /
• 제15권5호
• /
• pp.77-82
• /
• 2011

SiC particulate reinforced Al matrix composites with different SiC volume fractions were fabricated by thermal spray process. And the dry sliding wear test were performed on these composites using the applied load of 10 N, rotational speed of 30 rpm, radius of rotation 15 mm. Wear tracks on the Al/SiC composites were investigated using scanning electron microscope(SEM) and energy dispersive spectroscopy (EDS). It was observed that wear behavior of Al/SiC composites and formation of MML was changed dramatically according to reinforcement volume fraction.