• 대한기계학회논문집A
• /
• 제20권2호
• /
• pp.399-407
• /
• 1996

A fuzzy learning algorithm to get the optimal fuzzy rules is presented in this paper. The algorithm introduces a reference model to generate a desired output and a performance index funtion instead of the performance index table. The performance index funtion is a cost function based on the error and error-rate between the reference and plant output. The cost function is minimized by a gradient method and the control input is also updated. In this case, the control rules which generate the desired response can be obtained by changing the portion of the error-rate in the cost funtion. In SISO(Single-Input Single- Output)plant, only by the learning delay, it is possible to experss the plant model and to get the desired control rules. In the long run, this algorithm gives us the good control rules with a minimal amount of prior informaiton about the environment.

• 한국컴퓨터정보학회논문지
• /
• 제12권4호
• /
• pp.209-219
• /
• 2007

100PPM 품질인증시스템은 1995년 공업진흥청의 주도하에 추진되어져, 우리나라 산업부분의 품질경쟁력 제고에 기여하였다. 2000년에는 국내의 중소기업을 대상으로 보다 더 완벽한 수준의 Single PPM 품질인증시스템으로 상향 조정토록 하였고, 출하불량률과 시장 불량률 수준을 10ppm 이하로 줄이는 것을 품질목표로 하고 있다. 현재까지 1.818개의 회사들이 Single PPM 품질인증시스템을 인증 받았으며, Single PPM 품질혁신운동은 21C의 사회 경제적인 무결점 목표를 달성하기 위한 품질혁신운동이다. 이 논문의 목적은 Single PPM 품질혁신운동이 현재 처해있는 문제점들을 개선하고자, Kano 모델에 기반을 둔 글로벌 지속가능 품질혁신(GSQI) 지수를 개발하고, 이를 통하여 Single PPM 품질혁신운동의 개선을 도모하고자 함이다.

• The Journal of Asian Finance, Economics and Business
• /
• 제7권9호
• /
• pp.135-145
• /
• 2020

This paper provides the practical application of a linear shrinkage framework on Vietnam stock market. The cumulative data points observed in this analysis are 468 weeks from January 2011 to December 2019. All the companies listed on Ho Chi Minh City Stock Exchange (HOSE), except the companies under two years period from Initial Public Offering (IPO), are considered. The cumulative number of stocks picked is therefore 350 companies. The VNINDEX, which is the Vietnam Stock Index, is used as a reference index for shrinking to a single-index model. The empirical results show that the shrinkage of covariance matrix for portfolio optimization gives the promising results for the investors on Vietnam stock market. The shrinkage method helps the investors to produce the optimal portfolio in the sense of having higher profit with lower levels of risk compared to the portfolio of the traditional SCM method. Moreover, the portfolio turnover of shrinkage method is always kept at low magnitudes, and this makes the shrinkage portfolios save much transaction costs and reduce the liquidity risks in the trading process. In addition, the ability of shrinkage method in making profit is once again confirmed by the Alpha coefficient that achieves a high positive value.

• 대한전기학회논문지
• /
• 제39권5호
• /
• pp.478-484
• /
• 1990

An automatic tuning method of a PID controller which is used for single input single output processes is proposed. In the proposed tuning method, the frequency response data model is adopted along with the performance index which is an integral of time weighted square error between reference model and process frequency response data model for tuning. This method is easier to retune when either the process dynamics is changed or the reference model is changed. Finally, an example is provided to show the usefulness of the method.

• 디지털산업정보학회논문지
• /
• 제10권1호
• /
• pp.17-27
• /
• 2014

The number of manufacturing companies that demand the ability to assess sustainability in their manufacturing system is rapidly increasing. However, there are still difficulties in assessing their sustainability in manufacturing for decision-making since it is not easy to determine a single index of sustainability in an operational way. To address these difficulties, this paper proposes an operational guidance and system to assess sustainability of production plan as a single index. The IDEF0 model was defined to explain processes and their input, output, control, and mechanism for sustainability assessment. A prototype system was developed based on the concepts presented in the IDEF0 model, and applied to a case study. To conclude, the prototype system proposed in this paper can help manufacturing companies assess sustainability of their production plans and make a decision using a single value resulted from that assessment.

• Structural Engineering and Mechanics
• /
• 제60권5호
• /
• pp.875-890
• /
• 2016

A new structural damage index for seismic fragility analysis of reinforced concrete columns is developed based on a local tensile damage variable of the Lee and Fenves plastic-damage model. The proposed damage index is formulated from the nonlinear regression of experimental column test data. In contrast to the response-based damage index, the proposed damage index is well-defined in the form of a single monotonically-increasing function of the volume weighted average of local damage distribution, and provides the necessary computability and objectivity. It is shown that the present damage index can be appropriately zoned to be used in seismic fragility analysis. An application example in the computational seismic fragility evaluation of reinforced concrete columns validates the effectiveness of the proposed damage index.

• 한국융합학회논문지
• /
• 제5권4호
• /
• pp.163-169
• /
• 2014

A stable neural network control scheme for unknown non-linear systems is developed in this paper. While the control variable is optimised to minimize the performance index, convergence of the index is guaranteed asymptotically stable by a Lyapnov control law. The optimization is achieved using a gradient descent searching algorithm and is consequently slow. A fast convergence algorithm using an adaptive learning rate is employed to speed up the convergence. Application of the stable control to a single input single output (SISO) non-linear system is simulated. The satisfactory control performance is obtained.

• 한국항공운항학회지
• /
• 제20권4호
• /
• pp.76-83
• /
• 2012

Korean aviation Turbulenc Guidance (KTG) system is developed using the operational unified model (UM) of the Korea Meteorological Administration (KMA) and pilot reports (PIREPs) over East Asia. The KTG system comprised of twenty turbulence diagnostics that represent various turbulence potentials and have the best forecasting skills, which are combined into a single ensemble-averaged index, namely KTG, at upper-(above FL250) and mid-(below FL250) levels. It is found that the overall performance of the KTG is higher than those produced from the one single best index, and satisfies the minimum criteria (80% accuracy) that the system is operationally useful in aviation industry.

• 한국도로학회논문집
• /
• 제19권5호
• /
• pp.1-11
• /
• 2017

PURPOSES : This study is aimed at development of a stochastic pavement deterioration forecasting model using National Highway Pavement Condition Index (NHPCI) to support infrastructure asset management. Using this model, the deterioration process regarding life expectancy, deterioration speed change, and reliability were estimated. METHODS : Eight years of Long-Term Pavement Performance (LTPP) data fused with traffic loads (Equivalent Single Axle Loads; ESAL) and structural capacity (Structural Number of Pavement; SNP) were used for the deterioration modeling. As an ideal stochastic model for asset management, Bayesian Markov multi-state exponential hazard model was introduced. RESULTS:The interval of NHPCI was empirically distributed from 8 to 2, and the estimation functions of individual condition indices (crack, rutting, and IRI) in conjunction with the NHPCI index were suggested. The derived deterioration curve shows that life expectancies for the preventive maintenance level was 8.34 years. The general life expectancy was 12.77 years and located in the statistical interval of 11.10-15.58 years at a 95.5% reliability level. CONCLUSIONS : This study originates and contributes to suggesting a simple way to develop a pavement deterioration model using the total condition index that considers road user satisfaction. A definition for level of service system and the corresponding life expectancies are useful for building long-term maintenance plan, especially in Life Cycle Cost Analysis (LCCA) work.

• 화약ㆍ발파
• /
• 제36권2호
• /
• pp.1-9
• /
• 2018

폴리머 겔의 발파 효과를 평가하기 위해 AUTODYN을 이용한 단일 발파공 모델 시뮬레이션을 수행하였다. 발파공 내부 에멀젼 폭약과 공벽간의 채움재는 공기와 폴리머 겔을 적용하여 서로 결과를 비교하였으며, 디커플링 지수 1.0인 밀장전과 디커플링 지수 1.25, 1.56에 대해 각각 해석하였다. 폴리머 겔의 발파 효과 평가를 위한 기준은 밀장전 case를 기준으로 하였다. 해석 결과로서 석회석 모델의 파쇄 및 균열 발생에서 공기보다 폴리머 겔 적용의 경우가 높은 파쇄 정도를 나타냈고, 지정 게이지에서의 최고압력 또한 공기의 경우보다 폴리머 겔 적용이 높은 수치를 보였다.