• 산업경영시스템학회지
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• 제45권1호
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• pp.31-40
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• 2022

Six Sigma is a philosophy and systematic methodology for quality improvement. It encourages continuous quality improvement efforts to achieve the ideal goal of 6σ. Sigma(σ) is a statistic representing the standard deviation of the normal distribution, and 6σ level means a level where the tolerance of the specification is six times the standard deviation of the process distribution. In terms of the defective rate, the 6σ level achieves the 0.002 defectives per one million units. However, in the field, the 6σ level is used in the sense of achieving 3.4 defects per one million opportunities, which shows a large gap from the 6σ level in the statistical viewpoint. This is because field practitioners accept a 1.5σ shift of the mean of process when calculating the defective rate under sigma level. It said that the acceptance of 1.5σ shift of the mean is from experience, but there is no research or theoretical explanation to support it logically. Although it is a non-scientific explanation based on experience, considering that there has been no objection to the 1.5σ shift for a long time and it is rather accepted, it is judged that there is a reasonable basis for the 1.5σ shift. Therefore, this study tries to find a reasonable explanation through detective power of control chart via the run-rules to the 1.5σ shift empirically recognized by practitioners.

• 인터넷정보학회논문지
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• 제12권4호
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• pp.45-50
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• 2011

본 논문에서는 차량용 다중 카메라시스템에서 무선영상을 전송하기 위해 FH/TDD(Frequency Hopping/Time Division Duplex) 기반의 Motion JPEG 영상압축 코덱의 부호화 지연시간을 분석한다. 또한, Motion JPEG기반으로 FH/TDD에 의한 다중접속을 위해 시분할 시에 상호 동기화된 채널이동 과 접근방식(Synchronized shift & access)이 가능하도록 채널의 상태를 파악한 후, 채널충돌(Channel Collision)을 최소화하기 위한 동기화 연결(Synchronized connection) 방식을 설계한다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 학술대회 논문집 정보 및 제어부문
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• pp.333-334
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• 2008

A real-time face tracking is a broad topic, covering a large spectrum of technologies and applications. Briefly face tracking is a kind of tracing technique which follows human face in any directions. It needs some algorithms such as human face detection and motion controller to track face. Moreover, both processing time and calculation time are the most important factors that influence to drive tracking system. In this paper, two algorithms are used to find human face: earn-shift algorithm and face detection algorithm using OpenCV. Fuzzy controller is utilized to move pan-tilt camera system which can move four directions along to x-y axis.

• Rapid Communication in Photoscience
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• 제3권4호
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• pp.85-87
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• 2014

We studied the characteristics of emissive state of the first (p-G1) and second (p-G2) generation of phenylacetylene dendrimers bearing stilbene as a core by using time-resolved fluorescence spectroscopy in cyclohexane (c-Hex) and N, N-dimethylformide (DMF), which are nonpolar and polar solvents, respectively. Time-dependent red-shift of emission spectra p-G2 both in c-Hex and DMF was observed in comparison with p-G1. Besides, the time constant of red-shift of spectra was found to be larger in DMF than in c-Hex. This indicates that the emissive state of p-G2 has a polar character in DMF as a result of charge delocalization from core to peripheral dendrons followed by stabilization of emissive state.

• 대한전자공학회논문지TC
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• 제46권3호
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• pp.15-18
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• 2009

본 논문에서는 수신기에서 채널 추정을 필요로 하지 않는 MWSK (M-ary orthogonal Walsh sequence keying)를 적용한 ST-MWSK (space-time MWSK)를 제안한다. ST-MWSK의 noncoherent ML (maximum-likelihood) 검출기의 계산 복잡도는 기존의 ST-FSK (ST frequency-shift keying) 방식에 비해 크게 줄어든다. 또한 ST-MWSK는 ST-FSK와 거의 동일한 성능을 나타낸다.

• 한국도로학회논문집
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• 제14권5호
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• pp.75-83
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• 2012

PURPOSES: Suggestion of asphalt binder constitutive model based on time-temperature superposition principle and overstress concept in order to describe behavior of asphalt binders. METHODS: A series of temperature sweep tests and multiple stress creep and recovery(MSCR) tests are performed to verify the applicability of time-temperature superposition principle(t-Ts) and to develop viscoelastoplastic constitutive equation based on overstress concept. For the tests, temperature sweep tests at various high temperature and various frequency and MSCR test at $58^{\circ}C$, $64^{\circ}C$ $70^{\circ}C$, $76^{\circ}C$, and $82^{\circ}C$ are performed. From the temperature sweep tests, dynamic shear modulus mastercurve and time-temperature shift function are built and the shift function and MSCR at $58^{\circ}C$ are utilized to determine model coefficients of VBO model. RESULTS: It is observed that the time-temperature shift function built at low strain level of 0.1% is applicable not only to 1.0% strain level temperature sweep test but also maximum 500,00% strain level of MSCR test. As well, the modified VBO model shows perfect prediction on MSCR measured strain at the other temperatures. CONCLUSIONS: The Time-temperature superposition principle stands hold from very low strain level to very high strain level and that the modified VBO model can be applicable for various range of strain and temperature region to predict elastic, viscoelastic, and viscoplastic strain of asphalt binders.

• 정보처리학회논문지A
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• 제9A권2호
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• pp.197-206
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• 2002

통신과 계산 작업을 중첩 수행함으로써 통신 시간의 감춤 효과를 얻는 것은 일반적인 병렬 프로그램 최적화 방법 중의 하나이다. 본 논문에서는 데이타 병렬 프로그램에서 자주 사용되는 군집 통신(collective communication)의 하나인 원형 쉬프트(circular shift) 통신에 대해 중첩 효과를 실험하고 고찰하였다. 이더넷 스위치로 연결된 클러스터 시스템에서 원형 쉬프트 통신을 수행할 때, 중첩으로 얻을 수 있는 최대 이득과 중첩할 수 없는 시간을 측정하였다. 각 플랫폼 별로 이러한 측정값들을 얻어 퇴적화 컴파일러의 입력으로 활용할 수 있을 것이다. 한편 기존의 성능 모델을 통해 퇴적화하는 것은 크게 두가지 문제를 갖고 있다. 하나는 기본적인 점대점 통신에 입각한 모델을 제공하기 때문에 통신 라이브러리의 함수를 사용할 때의 종합적인 효과, 특히, 군집 통신과 같은 경우에는 적용하기 어렵다는 것이다. 다른 하나는 군집 통신의 성능은 분석은 가능하지만, 중첩 효과는 분석할 수 없다는 것이다. 본 논문에서는 이러한 기존 모델의 단점을 보완하여 확장하였다. 또한, 원형 쉬프트 통신에 대한 실험 결과를 토대로 확장된 모델의 매개 변수 값들을 추출하여 예제 프로그램을 통해 분석하였다.

• 유통과학연구
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• 제14권1호
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• pp.93-102
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• 2016

Purpose - The purpose of paper is studying the static and dynamic side for long-term memory storage properties, and increase the explanatory power regarding the long-term memory process by looking at the long-term storage attributes, Korea Composite Stock Price Index. The reason for the use of GPH statistic is to derive the modified statistic Korea's stock market, and to research a process of long-term memory. Research design, data, and methodology - Level shifts were subjected to be an empirical analysis by applying the GPH method. It has been modified by taking into account the daily log return of the Korea Composite Stock Price Index a. The Data, used for the stock market to analyze whether deciding the action by the long-term memory process, yield daily stock price index of the Korea Composite Stock Price Index and the rate of return a log. The studies were proceeded with long-term memory and long-term semiparametric method in deriving the long-term memory estimators. Chapter 2 examines the leading research, and Chapter 3 describes the long-term memory processes and estimation methods. GPH statistics induced modifications of statistics and discussed Whittle statistic. Chapter 4 used Korea Composite Stock Price Index to estimate the long-term memory process parameters. Chapter 6 presents the conclusions and implications. Results - If the price of the time series is generated by the abnormal process, it may be located in long-term memory by a time series. However, test results by price fixed GPH method is not followed by long-term memory process or fractional differential process. In the case of the time-series level shift, the present test method for a long-term memory processes has a considerable amount of bias, and there exists a structural change in the stock distribution market. This structural change has implications in level shift. Stratum level shift assays are not considered as shifted strata. They exist distinctly in the stock secondary market as bias, and are presented in the test statistic of non-long-term memory process. It also generates an error as a long-term memory that could lead to false results. Conclusions - Changes in long-term memory characteristics associated with level shift present the following two suggestions. One, if any impact outside is flowed for a long period of time, we can know that the long-term memory processes have characteristic of the average return gradually. When the investor makes an investment, the same reasoning applies to him in the light of the characteristics of the long-term memory. It is suggested that when investors make decisions on investment, it is necessary to consider the characters of the long-term storage in reference with causing investors to increase the uncertainty and potential. The other one is the thing which must be considered variously according to time-series. The research for price-earnings ratio and investment risk should be composed of the long-term memory characters, and it would have more predictability.

• 정보처리학회논문지B
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• 제17B권1호
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• pp.15-22
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• 2010

비디오 감시 시스템에서 정확한 물체 추적을 위해서는 움직이는 물체가 없는 정적인 배경 영상이 필수적이다. 하지만 기존의 배경 생성 방법들은 주로 시간 축에 따른 화소 정보를 이용하여 오랫동안 정지해 있는 물체들이 존재하는 경우에는 적용하기 어려운 단점이 있다. 이러한 문제점을 해결하기 위해 본 논문에서는 mean-shift와 fast marching method(FMM)을 이용해 시간 축 화소 정보와 공간 축 화소 정보를 이용하여 배경을 생성하는 방법을 제안한다. mean-shift를 이용해 시간 축에 따른 화소 값의 최빈값을 추정하여 배경을 생성하고, FMM을 이용해공간 축에 따른 화소 정보를 이용하여 일정 기간 동안 움직이지 않은 물체가 있는 환경에서 바람직한 배경을 생성한다. 실험 결과는 제안한 방법이 기존의 시간에 따른 빈도만을 이용하는 방법보다 더 효율적임을 보여준다.

• 대한간호학회지
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• 제40권1호
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• pp.43-51
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• 2010

Purpose: The purpose of this study was to investigate sleep habits, sleep disturbance, and circadian types, and to identify factors influencing sleep disturbance in nursing students. Methods: Participants were 140 senior nursing students. The data were collected from May 19 to 27, 2008 using self-report questionnaires. Results: 1) Evening type delayed sleep-wake schedules were more frequent than for morning type, especially during weekend and evening shift duty. 2) In total sleep time, there were no significant statistical differences between morning type and evening type during weekdays, weekend, day or evening shift duty. 3) On weekdays and day shift duty, the mean score for sleep disturbance was significantly higher in the evening type compared to the morning type. 4) Sleep disturbance in weekday and day shift duty was influenced by circadian types, eating habits, and gender. Conclusion: The circadian types are a very important factor for determining the sleep quantity and quality in nursing students.