• Title/Summary/Keyword: Six sigma

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STATISTICAL ALGORITHMS FOR ENGINE KNOCK DETECTION

  • Stotsky, A.
    • International Journal of Automotive Technology
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    • v.8 no.3
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    • pp.259-268
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    • 2007
  • A knock detection circuit that is based on the signal of an accelerometer installed on the engine block of a spark ignition automotive engine has a band-pass filter with a certain frequency as a parameter to be calibrated. A new statistical method for the determination of the frequency which is the most suitable for the knock detection in real-time applications is proposed. The method uses both the cylinder pressure and block vibration signals and is divided into two steps. In both steps, a new recursive trigonometric interpolation method that calculates the frequency contents of the signals is applied. The new trigonometric interpolation method developed in this paper improves the performance of the Discrete Fourier Transformation, allowing a flexible choice of the size of the moving window. In the first step, the frequency contents of the cylinder pressure signal are calculated. The knock is detected in the cylinder of the engine cycle for which at least one value of the maximal amplitudes calculated via the trigonometric interpolation method exceeds a threshold value indicating a considerable amount of oscillations in the pressure signal; this cycle is selected as a knocking cycle. In the second step, the frequency analysis is performed on the block vibration signal for the cycles selected in the previous step. The knock detectability, which is an individual cylinder attribute at a certain frequency, is verified via a statistical hypothesis test for testing the equality of two mean values, i.e. mean values of the amplitudes for knocking and non-knocking cycles. Signal-to-noise ratio is associated in this paper with the value of t-statistic. The frequency with the largest signal-to-noise ratio (the value of t-statistic) is chosen for implementation in the engine knock detection circuit.

A Case Study on BSC System Development of Korean Public Firms: Focused on Korea Post (국내 공기업의 BSC 시스템 구축 사례연구: 우정사업본부를 중심으로)

  • Shin, Taek-Soo;Yoo, Seung-Rock
    • Information Systems Review
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    • v.9 no.1
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    • pp.311-341
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    • 2007
  • This paper presents a case study on BSC(Balanced Scorecard) system development of Korea Post as a Korean public firm. BSC models of public or private sector are generally developed in different types due to their different strategic goals. Korea Post as a government firm has dual characteristics of BSC similar to both public and private sector. This firm has the organizational type of public firms, not private firms. To date many government subsidiary organizations have already introduced BSC or are trying to introduce BSC, but have difficulty in developing BSC successfully because of insufficient understanding of BSC. Based on a case study of Korea Post, this study analyzed key success and failure factors and suggested prospects on BSC system development of public firms.

On the asymptotic correlationship for some process capability indices Ĉp, Ĉpk and Ĉpm (공정능력지수 Ĉp, Ĉpk와 Ĉpm를 위한 점근적 상관성에 관한 연구)

  • Cho, Joong-Jae;Yu, Hye-Kyung
    • Journal of the Korean Data and Information Science Society
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    • v.24 no.3
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    • pp.465-475
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    • 2013
  • Higher quality level is generally perceived by customers as improved performance by assigning a correspondingly higher satisfaction score. Usually, the quality level is measured by process capability indices. The index is used to determine whether a production process is capable of producing items within a specified tolerance. Some useful process capability indices $C_p$, $C_{pk}$ and $C_{pm}$ have been widely used in six sigma industries to assess process performance. Most evaluations on process capability indices focus on point estimates, which may result in unreliable assessments of process performance. It is necessary to investigate their asymptotic correlationship among process capability indices $\hat{C}_p$, $\hat{C}_{pk}$ and $\hat{C}_{pm}$. In this paper, we study their asymptotic correlationship for some process capability indices $\hat{C}_p$, $\hat{C}_{pk}$ and $\hat{C}_{pm}$ under the normal process.

The Study on influence of test factors for WorldSID injury through AE-MDB side crash test (AE-MDB시험 시 인체모형 상해치에 대한 시험 인자 영향성 연구)

  • Sun, Hongyul;Han, Pyokyong;Oh, Eunkyung;Yoon, Ilsung
    • Journal of Auto-vehicle Safety Association
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    • v.7 no.1
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    • pp.7-12
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    • 2015
  • NCAP(New Car Assessment Program) makes vehicle manufacturer improve safety performance through free competition and customers guarantee vehicle selection by providing information of vehicle safety. That's why it is important not only to meet the regulation, but also to cope with NCAP. EuroNCAP(European New Car Assessment Program) side tests have conducted by using Progressive MDB and Euro SID II in order to reproduce crash test between two vehicles over 10 years. However various researches report that Progressive MDB and Euro SID II do not reflect evolving vehicle design, impact performance and biofidelity of human. Therefore EuroNCAP has the plan to conduct AE-MDB side crash test using WorldSID which is more evolved from 2015 by replacing Progressive MDB and EuroSID II. Automobile manufacturers need to develop safety performance for new test closely. This paper is to find test set-up parameters which affect into dummy injury instead of restraint system and to research on its tendency. It is processed with mini and small car to know influence as changing vehicle size and also analyzed by DFSS(Design for six sigma) which is one of optimization tools. DFSS is vaildated by simulating CAE with L18 orthogonal array of 6 control factors adjustable as EuroNCAP requirement.

A study on user satisfaction in TUI environment (TUI 환경의 유저 사용 만족도 연구)

  • Choi, heungyeorl;Yang, seungyong
    • Journal of Korea Society of Digital Industry and Information Management
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    • v.11 no.4
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    • pp.113-127
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    • 2015
  • An interface in smart device environment is changing to TUI(touch user interface) environment where a system is being controlled by physical touch, differently from a system controlled through conventional mouse and keyboard. What is more important than anything else in this TUI environment is to implement interface in consideration of learn ability and cognitive constructivism according to user's experience. Therefore, now is the time when it is necessary to carry out various studies on smart content design process going a step farther together with discussing the details of user's experience factor. Hence, this study was intended to look into what effect a user's experiential traits had on the production of contents for the purpose of measures for improving TUI user satisfaction in order to effectively realize contents in smart environment. Results were yielded by using a statistical empirical analysis such as cross-tabulation analysis according to important variable and user, paired t-test, multiple response analysis, and preference frequency analysis of user preference on the basis of a survey. As a result, a system was presented for implementing DFSS(Design For Six Sigma) process. TUI experience factor can be divided into direct habitual experience, direct learning experience, indirect habitual experience, and indirect learning experience. And in the results of study, it was possible to find that the important variables of this study had a positive effect on the improvement of use satisfaction with contents on the whole according to the user convenience of smart contents. This study is expected to have a positive effect on efficient smart device-based contents production by providing objective information according to empirical analysis to smart media-based developer and designer and presenting a model for improving the changed TUI usability.

Two Crystal Structures of Ag+-and TI+-Exchanged Zeolite X, Ag27TI65-X and Ag23TI69-X

  • Kim, Soo-Yeon;Choi, Eun-Young;Kim, Yang
    • Bulletin of the Korean Chemical Society
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    • v.23 no.12
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    • pp.1759-1764
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    • 2002
  • Two crystal structures of dehydrated $Ag^+-andTl^+$-exchanged zeolite X$Ag_{27}Tl_{65-}X\;and\;Ag_{23}Tl_{69-}X$have been determined by single-crystal X-ray diffraction techniques in the cubic space group Fd3 at 21(1) $^{\circ}C(a=24.758(4)\AAa=24.947(4)$, ${\AA}respectively).$, Their structures were refined to the final error indices $R_1$=0.055 and $wR_2$=0.057 with 375 reflections, and $R_1$=0.057 and $wR_2$=0.057 with 235 reflections, respectively, for which I > $3\sigma(I).$ In the structure of $Ag_{27}Tl_{65-}X,\;27\;Ag^+$ ions were found at two crystallographic sites: 15$Ag^+$ ions at site I at the center of the hexagonal prism and the remaining 12$Ag^+$ ions at site II' in the sodalite cavity. Sixty-five $Tl^+$ ions were located at three crystallographic sites: 20$Tl^+$ ions at site II opposite single six-rings in the supercage, 18$Tl^+$ ions at site I' in the sodalite cavity opposite the D6Rs, and the remaining 27$Tl^+$ ions at site III' in the supercage. In the structure of $Ag_{23}Tl_{69-}X$, 23$Ag^+$ ions were found at two crystallographic sites: 15 at site I and 8 at site II'. Sixty-nine $Tl^+$ ions are found at four crystallographic sites: 24 at site II, 17 at stie I', and the remaining 28 at two III' sites with occupancies of 22 and 6.

Effects of Ethanolic Extracts of Scutellaria Radix on the alveolar bone formation in the extract socket of rat (황금(Scutellaria Radix)의 에타놀 추출물이 백서 치조골 형성에 미치는 영향)

  • Park, Joon-Bong;Herr, Yeek;Kwon, Young-Hyuk;Bae, Ki-Hwan;Chung, Chong-Pyung
    • Journal of Periodontal and Implant Science
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    • v.27 no.3
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    • pp.443-457
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    • 1997
  • The purpose of this study was to evaluate the effects of ethanolic extracts of Scutellaria Radix on the alveolar bone formation in the extract socket of rat. Thirty-six Sprague-dawley rats were used in this study. Mean body weight of rat was $130{\pm}5g$. Experimental animal were administered 0.4% ,${\beta}-aminopropionitril$(Sigma, USA) with the solid commercial food for 5 days. All the maxillary 1st molar of the rats were extracted by using of the tissue forcep under the general anesthesia with Pentobarbital sodium(Tokyo Chemical Co, Japan) injection into intraperitoneal space. All the extracted rats were divided into two group, experimental group which were feeded the solid food mixed ethanolic extracts of Scutellaria Radix, and control group which were feeded same food without reagent. At 1, 3, 5, 7, 9 and 14th days after tooth extraction, rats in both groups were serially sacrificed respectively. All the specimen were treated as usual method and prepared Hematoxylin-eosin stain for the light microscopic observation. The results were as follows : 1. Bone formation of extracted socket starts from the area on remained periodontal ligament than other area. 2. In the case of administration of the extracted Scutellaria Radix showed rapid healing process of connective tissue than non-administrated group. 3. In the case of administration of the extracted Scutellaria Radixshowed rapid osteogenesis than non-administrated With above results, it was concluded that ethanolic extracts of Scutellaria Radix may play a favorable role on the healing process of exatraction socket after extraction in rats. It was suggested that further study to evaluate the different concentration and administration method of ethanolic extracts of the Scutellaria Radix into same experimental model.

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Agent Based Process Management Environment (에이전트 기반의 프로세스 관리 환경에 관한 연구)

  • Kim, Jeong-Ah;Choi, Seung-Young;Choi, Sung-Woon
    • The KIPS Transactions:PartD
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    • v.13D no.5 s.108
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    • pp.691-698
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    • 2006
  • The companies need the enterprise-wide support environment to build the competency to gather VOM(Voice of Market) in the process of preparing and implementing the strategy and to help establishing and managing the business process in order to secure the continuous competitive edge The enterprise-wide support environment to establish, operate, improve and evaluate the business process must be carried out. In this paper we define the method to define process and business rule in order to enable accurate execution of the process. Furthermore, collection and refection of accurate data concerning the competency of individuals, the subjects of the process execution, allows prevention of weakness of the process execution result and is the basis for identifying the areas of improvement. Therefore, high visibility can be attained through the work knowledge and processes presented in rules, and it can help firmly establish the process centered work culture (or system) in the organization by process improvement strictly based on data.

Two Crystal Structures of Ethylene and Acetylene Sorption Complexes of Dehydrated Fully $Ca^{2+}$-Exchanged Zeolite A

  • Jang, Se-Bok;Moon, Sung-Doo;Park, Jong-Yul;Kim, Un-Sik;Kim, Yang
    • Bulletin of the Korean Chemical Society
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    • v.13 no.1
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    • pp.70-74
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    • 1992
  • Two crystal structures of ethylene (a= 12.272(2) ${\AA}$) and acetylene (a = 12.245(2) ${\AA}$) sorption complexes of dehydrated fully $Ca^{2+}$-exchanged zeolite A have been determined by single crystal X-ray diffraction techniques in the cubic space group, Pm3m at $21(1)^{\circ}C$. Their complexes were prepared by dehydration at $360^{\circ}C$ and $2{\times}10^{-6}$ Torr for 2 days, followed by exposure to 200 Torr of ethylene gas and 120 Torr of acetylene gas both at $24^{\circ}C$, respectively. The structures were refined to final R (weighted) indices of 0.062 with 209 reflections and 0.098 with 171 reflections, respectively, for which I > 3${\sigma}$(I). The structures indicate that all six $Ca^{2+}$ ions in the unit cell are associated with 6-oxygen ring of the aluminosilicate framework. Four of these extend somewhat into the large cavity where each is coordinated to three framework oxide ions and an ethylene molecule and/or an acetylene molecule. The carbon to carbon distance in ethylene sorption structure is 1.48(7) ${\AA}$ and that in acetylene sorption structure 1.25(8) ${\AA}$. The distances between $Ca^{2+}$ ion and carbon atom are 2.87(5) ${\AA}$ in ethylene sorption structure and 2.95(7) ${\AA}$ in acetylene sorption structure. These bonds are relatively weak and probably formed by the electrostatic attractions between the bivalent $Ca^{2+}$ ions and the polarizable ${\pi}$-electron density of the ethylene and/or acetylene molecule.

MEASURING PERFORMANCE IN EGYPTIAN CONSTRUCTION FIRMS APPLYING QUALITY MANAGEMENT SYSTEMS

  • Manal S. Abd Elhamid;Sahar. Sh. Ghareeb;Ramadan O. Mohamed
    • International conference on construction engineering and project management
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    • 2011.02a
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    • pp.149-156
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    • 2011
  • The performance measurement of construction firms is considered as a competitive advantage to develop and improve their performance to have place in the market and stay able to face the continuous challenge. Egyptian construction firms (ECF) started recently to adopt quality management system (QMS) as a way to develop and improve their performance as previous studies showed. However, measuring that performance to include all the firm's aspects in a competitive way is a crucial process for the ECF's culture. The research is trying to indicate the role of the QMS implementation in measuring performance (MP) through developing a model for measuring performance on the organization level, and explore its impact on the organization that adopt quality management system. This model is based on specific elements and their related indicators which have been derived from national approaches and models of measuring performance (benchmarking, quality awards and six sigma).Elements determination and the status of their real practice has been investigated through a questionnaire to a representative sample of ECF. This model determines the performance level (PL) of the organization that measured by a mean of a point system. Weights of the elements in the point system considered both the elements' importance in the international models and its real practice in the Egyptian construction firms. So, the final outcome of the model reveals the level of firm performance that helps the firm to identify the weak points against the strong ones, Confirm the priorities and identify new opportunities for developing, and Check the position of the company in the market among the others. Another questionnaire has been developed to be distributed on a group of Experts on measuring performance for the purpose of model validation. The majority of surveyed experts agreed that the proposed model can be applied effectively.

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