• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 추계학술대회 논문집 Vol.17
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• pp.57-60
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• 2004

This paper presents multibit Sigma-Delta ADC using Leslie-Singh Structure to Improve nonlinearity of feedback loop. 4-bit flash ADC for multibit Quantization in Sigma Delta modulator offers the following advantages such as lower quantization noise, more accurate white-noise level and more stability over single quantization. For the feedback paths consisting of DAC, the DAC element should have a high matching requirement in order to maintain the linearity performance which can be obtained by the modulator with a multibit quantizer. Thus a Sigma-Delta ADC usually adds the dynamic element matching digital circuit within feedback loop. It occurs complexity of Sigma-Delta Circuit and increase of power dissipation. In this paper using the Leslie-Singh Structure for improving nonliearity of ADC. This structure operate at low oversampling ratio but is difficult to achieve high resolution. So in this paper propose improving loop filter for single-bit feedback multi-bit quantization Sigma-Delta ADC. It obtained 94.3dB signal to noise ratio over 615kHz bandwidth, and 62mW power dissipation at a sampling frequency of 19.6MHz. This Sigma Delta ADC is fabricated in 0.25um CMOS technology with 2.5V supply voltage.

• 전자공학회논문지
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• 제54권1호
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• pp.26-32
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• 2017

본 논문에서는 설계 요구가 높고, 전력 소모가 높은 opamp를 이용하는 기존의 능동형 적분기를, 수동형 적분기로 대체하여 고속의 저전력, 고해상도 특성을 갖는 incremental delta-sigma ADC를 소개한다. 능동형 적분기에서 수동형 적분기로의 변환을 위해, 기존의 능동형 적분기의 특성을 분석하였다. 이를 바탕으로 opamp의 설계 요구를 낮추고, 더 나아가 opamp를 사용하지 않는 저전력의 수동형 적분기를 제안하였다. 65nm 공정을 이용하여 수동형 적분기로 구성된 1차 single-bit incremental delta-sigma ADC를 설계하였다. Transistor-level 시뮬레이션 결과, 이는 supply 전압이 1.2V인 상황에서 modulator만 0.6uW, digital filter를 포함한 ADC 전체에서 6.25uW를 소모하며 BW 22KHz, SNDR 71dB, dynamic range 74.6dB을 달성하였다.

• 대한화학회지
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• 제26권2호
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• pp.65-72
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• 1982

여러 형태의(n${\pi}$/m) 및 (n-${\sigma}^*$) 구조가 에너지에 미치는 구조적인 기여를 살펴보기 위하여 n-프로필아민, n-프로필아민 라디칼, trans-및 cis-에틸렌 디아민에 대한 STO-3G 수준의 계산을 수행하였다. 그 결과 (5${\pi}$/5)구조가 (4${\pi}$/4)구조는 각각 인력 및 반발의 비결합 상호작용을 나타내었으며 서로 부가관계를 가짐을 알았다. anti(n-${\sigma}^*$) 구조는 syn(n-${\sigma}^*$)구조보다 강한 hyperconjugation효과를 보이지만 anti(n-${\sigma}^*$)구조에서 강한 핵간 반발력을 가지기 때문에 결과적으로 불안정한 겉보기 효과를 나타내었다. 더우기 안정화${\pi}$ -비결합 (5${\pi}$/5)구조는 anti(${\pi}$-${\sigma}^*$)구조를, 불안정화 ${\pi}$-비결합(4${\pi}$/4)구조는 syn(n-${\sigma}^*$)구조를 수반하며 상호 보강적으로 작용함을 알았다. 또한 이러한 상호 보강성이 일반적인 성질임을 알았다. 끝으로 말단의 고립 전자쌍에 의한 through-bond 상호작용을 논의하였으며 이러한 상호작용으로 에너지 준위가 $n_+ = \frac{1}{\sqrt{2}}(n_1\;+\;n_2)$와 $n_-\;=\;\frac{1}{\sqrt{2}}(n_1\;-\;n_2)$로 갈라지는데 이때 고립 전자쌍의 간단한 overlap pattern으로 n_준위가 안정한 준위임을 알았다.

• BMB Reports
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• 제43권3호
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• pp.176-181
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• 2010

The primary sigma factor ($\sigma^{A}$) of Staphylococcus aureus, a potential drug target, was little investigated at the structural level. Using an N-terminal histidine-tagged $\sigma^{A}$ (His-$\sigma^{A}$), here we have demonstrated that it exits as a monomer in solution, possesses multiple domains, harbors primarily $\alpha$-helix and efficiently binds to a S. aureus promoter DNA in the presence of core RNA polymerase. While both N- and C-terminal ends of His-$\sigma^{A}$ are flexible in nature, two Trp residues in its DNA binding region are buried. Upon increasing the incubation temperature from 25$^{\circ}$ to 40$^{\circ}C$, $\sim$60% of the input His-$\sigma^{A}$ was cleaved by thermolysin. Aggregation of His-$\sigma^{A}$ was also initiated rapidly at 45$^{\circ}C$. From the equilibrium unfolding experiment, the Gibbs free energy of stabilization of His-$\sigma^{A}$ was estimated to be +0.70 kcal $mol^{-1}$. The data together suggest that primary sigma factor of S. aureus is an unstable protein. Core RNA polymerase however stabilized $\sigma^{A}$ appreciably.

• 품질경영학회지
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• 제34권4호
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• pp.110-124
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• 2006

There have been various papers about service quality. This article is one of them. This is about the measurement of service quality in the competitive structure between department and discount store. In this paper, we tried to measure the service quality and overall satisfaction by using 6 sigma, degree of combination and top2box which is a little bit different methodology from traditional ones. The data were collected by the internet survey from 1428 and 1605 department and discount store customers respectively. The result shows the different patterns in the each retail industry. Also, there is a significant difference in terms of sigma level in the each retail industry. Finally, we showed the summarized result as the 6 Sigma Portfolio Matrix.

• 산업경영시스템학회지
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• 제24권67호
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• pp.93-102
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• 2001

Many companies in Korea have introduced and put Six Sigma to the practical use recently, others are under consideration to introduce it. As we consider how to recognize and to apply it, we are able to know there is a difference among companies and it differently influence on those companies. In this paper, we analyze the structural differences between Quality Management and Six Sigma movements through the questiionnaire designed effectively to investigate them. We also examine the controversial points, suitability as the management model, the level of Quality Management and Six Sigma movements, and analyze how much the movements effect on the management activities. Finally, we show how to improve the Quality Management and Six Sigma movements in Korean companies.

• International Journal of Quality Innovation
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• 제8권1호
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• pp.1-14
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• 2007

The Six Sigma and Lean Production methodologies suggest that creating value for customers is the objective of a production process or an organisation. In the production context, "added value" dominates the discussion about the creation of value to customers. However, "added value" is often only defined conceptually or discussed at a strategic level, and the link between added value and customer value has not yet been well conceptualised. Therefore, the purpose of the paper is to develop a methodology to measure added value in order to complement the existing performance measures in Six Sigma and Lean Production by conceptualising the link between customer value and added value. The conceptual link "confirms" that quality, time, and costs are the elements of added value, which are transformed into a metric to express customer value. The implementation of the metric recommends the adoption of Lean (Six) Sigma and Lean Accounting (Activity Based Costing), which thus implies that "leanness" is an important "feature" of added value.

• Bulletin of the Korean Chemical Society
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• 제3권1호
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• pp.1-4
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• 1982

A quantitative treatment of ${\pi}$-nonbonded and $n-{\sigma}^{\ast}$ interactions and through-bond coupling effect was attempted using n-butane, n-butyl radical, and tetramethylene diradical. Results of STO-3G level calculations showed that: (1) conformational preferences can be predicted quantitatively based solely on the additive effect of ${\pi}$-nonbonded and $n-{\sigma}^{\ast}$ interactions, the predominant effect being the ${\pi}$-nonbonded interactions, (2) $(n-{\sigma}^{\ast})_{anti}$ is destabilizing whereas $(n-{\sigma}^{\ast})_{syn}$ is weakly stabilizing, which are contrary to what we expect from the normal $n-{\sigma}^{\ast}$ interaction, (3) througb-bond coupling of the two radical lobes is destabilizing for the triplet but stabilizing for the singlet tetramethylene diradical.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 하계학술대회 논문집 Vol.5 No.2
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• pp.1222-1225
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• 2004

This paper presents multibit Sigma-Delta ADC using noise-shaped dynamic element matching(DEM). 5-bit flash ADC for multibit quantization in Sigma Delta modulator offers the following advantages such as lower quantization noise, more accurate white-noise level and more stability over single quantization. For the feedback paths consisting of DAC, the DAC element should have a high matching requirement in order to maintain the linearity performance which can be obtained by the modulator with a multibit quantizer. The DEM algorithm is implemented in such a way as to minimize additional delay within the feedback loop of the modulator Using this algorithm, distortion spectra from DAC linearity errors are shaped. Sigma Delta ADC achieves 82dB signal to noise ratio over 615H7z bandwidth, and 62mW power dissipation at a sampling frequency of 19.6MHz. This Sigma Delta ADC is designed to use 0.25um CMOS technology with 2.5V supply voltage and verified by HSPICE simulation.

• 대한산업공학회지
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• 제32권4호
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• pp.323-337
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• 2006

Samsung, recognized as a global leading company, has huge and complex supply chain structures and has been improving them continuously for its fast-growing global businesses. SCM 6 Sigma is the state-of-the-art methodology developed through a combination of SCM innovation concepts accumulated from SCM Business Group in Samsung SDS and 6 Sigma which has successfully settled down as the management innovation tool for many companies in Samsung. The ultimate goal of SCM 6 Sigma is to train and develop future supply chain leaders who are more capable of leading SCM innovations. By leveraging the established 6 Sigma Belt System, Samsung aims to alleviate a shortage of SCM talents that has been a bottleneck in improving SCM performances at its group companies. This explains why SCM 6 Sigma is created. SCM 6 Sigma is the unique and critical component for Samsung to implement its various strategies for continuous improvement of its operations at a higher level of effectiveness and systematically as well. In return on these efforts, many SCM innovation projects have been successfully executed through SCM 6 Sigma up to today. In this paper, we introduce the methodology and explain the business rationale behind it together with its deployment case.