• 호남수학학술지
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• 제41권1호
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• pp.35-49
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• 2019

In this work, it is shown that the combination of operational techniques and the use of the principle of quasi-monomiality can be a very useful tool for a more general insight into the theory of matrix polynomials and for their extension. We explore the formal properties of the operational rules to derive a number of properties of certain class of matrix polynomials and discuss the operational links with various known matrix polynomials.

• 해양환경안전학회지
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• 제29권1호
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• pp.60-66
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• 2023

현재의 해양산업의 기술은 스마트 선박 및 자율운항선박 등의 개발과 같은 자율화 및 지능화와 환경규제의 강화에 맞추어 선박의 운항 효율성을 개선하는 친환경 선박을 위한 기술이 함께 개발되고 있다. 이러한 흐름에 맞추어, 세계각국에서는 선박의 안전운항을 보장하는 선에서 선박운항효율을 극대화하기 위해 다양한 방식으로 노력하고 있다. 본 연구에서는, 현존하는 선박운항효율 개선 기술이 운항 당시의 기상환경, 선박조종 등의 선박운항상태를 실시간으로 반영하지 못하는 문제를 개선하기 위해, 선박에서 수집한 선박운항데이터를 활용하여 실시간 선박운항효율 분석모델을 개발하고자 한다. 본 연구의 실시간 선박운항효율 분석모델은 연료소모를 기준으로 판단한 선박운항효율과 당시의 선박운항상태를 감안하여 판단한 선박운항효율을 비교하여, 식별된 선박운항효율의 타당성을 확인할 수 있는 모델이다. 분석의 주요 내용은 대상선박의 선정과 선박운항데이터의 수집, 선박운항효율 특성과 선박운항상태 특성의 구분, 그리고 이를 활용한 분류모델의 개발을 포함한다. 연구의 결과는 기존의 선박운항효율과 항해 당시 선박운항상태를 감안한 운항효율을 제시하여 선박 운항자의 의사결정을 지원하여 운항효율을 개선하고자 한다.

• 대한산업공학회지
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• 제29권1호
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• pp.21-31
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• 2003

Determination of operational dimensions and tolerances is complex if there exist inconsistencies between operational and design specifications. Dimension and tolerance charts (D&T charts) have been used to establish the relationships among operational dimensions in complex machining. This chart proves that individual operations can be harmonized when they are interconnected. However, it is hard to generate the chart manually. Because operational dimensions and tolerances must meet the design specifications, the dimensions and tolerances of interconnected operations have to be verified serially for economical operations. In this paper, the chart is automatically generated from the interconnected operations. More importantly, all operational dimensions and tolerances displayed in the chart have been verified by using LP to meet the design specifications. Finally, the chart is converted to an operational routing sheet that contains a detailed process plan along with cutting speed, feed rate, and operational references based on material hardness, surface finish, and tool nose radius.

• Structural Monitoring and Maintenance
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• 제2권2호
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• pp.115-132
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• 2015

This paper presents a new method for seismic vulnerability assessment of buildings with reference to their operational limit state. The importance of this kind of evaluation arises from the civil protection necessity that some buildings, considered strategic for seismic emergency management, should retain their functionality also after a destructive earthquake. The method is based on the identification of experimental modal parameters from ambient vibrations measurements. The knowledge of the experimental modes allows to perform a linear spectral analysis computing the maximum structural drifts of the building caused by an assigned earthquake. Operational condition is then evaluated by comparing the maximum building drifts with the reference value assigned by the Italian Technical Code for the operational limit state. The uncertainty about the actual building seismic frequencies, typically significantly lower than the ambient ones, is explicitly taken into account through a probabilistic approach that allows to define for the building the Operational Index together with the Operational Probability Curve. The method is validated with experimental seismic data from a permanently monitored public building: by comparing the probabilistic prediction and the building experimental drifts, resulting from three weak earthquakes, the reliability of the method is confirmed. Finally an application of the method to a strategic building in Italy is presented: all the procedure, from ambient vibrations measurement, to seismic input definition, up to the computation of the Operational Probability Curve is illustrated.

• 유통과학연구
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• 제20권12호
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• pp.89-98
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• 2022

Purpose: Due to the rapid growth of e-commerce in Thailand, the operational excellence of distribution service providers has been elevated. Thus, this research investigated the key drivers of operational performance of e-commerce distributors in Thailand. The research contains key variables: the analytics capabilities of an organization, supply chain disruption orientation, innovation capability, and operational performance. Research design, data, and methodology: An online survey is administered to top managers and key personnel (N=425) employed for at least one year in Thailand's top five e-commerce distributors. The sampling methods were conducted using purposive sampling, quota sampling, and convenience sampling. Confirmatory Factor Analysis and Structural Equation Model were applied to analyze and confirm the model's goodness-of-fit and hypothesis testing. Results: The findings reveal that an organization's analytics capabilities significantly affect supply chain disruption orientation and supply chain resilience. Furthermore, operational performance is affected by supply chain disruption, supplier quality management, and innovation capability. Nevertheless, supply chain resilience and digital supply chain have no significant effect on operational performance. Conclusions: The results imply that supply chain digitalization could drive higher operational performance. Distribution businesses are encountering transformation and disruption, which should address the high level of a digital supply chain, innovation, and quality management to maximize their profit margin and delivery service quality.

• 한국산학기술학회논문지
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• 제20권1호
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• pp.41-51
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• 2019

본 연구는 동적역량과 혁신성과 간의 관계를 탐험과 활용의 관점에서 구분된 운영역량과 IT역량이 조절하고 매개하는지를 조사하였다. 178개 기업의 설문지를 분석한 결과, 포착역량과 재구성역량이 점진적 혁신성과와 급진적 혁신성과에 정(+), 탐험적 운영역량과 활용적 운영역량이 점진적 혁신성과에 정(+), 탐험적 운영역량이 급진적 혁신성과에 정(+)의 영향을 미치고 있다. 또한 유의적인 상호작용항은 점진적 혁신성과에 대하여 '탐험적 운영역량*탐험적 IT역량', '탐험적 운영역량*활용적 IT역량', '활용적 운영역량*활용적 IT역량' 등이며, 급진적 혁신성과에 대하여 '탐험적 운영역량*탐험적 IT역량'이다. 유의한 매개효과가 검증된 경우는 7가지였다. 본 연구의 의미는 동적역량이 혁신성과에 미치는 영향을 직접 효과와 간접효과로 나누어 실증적인 연구를 최초로 시도하였으며 운영역량과 IT역량을 탐험과 활용 역량으로 구분하여 정밀한 분석을 하였다는 점이다. 본 연구 결과를 통하여 기업이 적응하고 진화하는데 동적역량과 운영역량이 상호보완적인 역할을 한다는 시사점을 얻을 수 있다.

• 한국산업정보학회논문지
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• 제25권6호
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• pp.95-107
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• 2020

본 연구의 목적은 코로나19가 국내에 유입되고 확산되는 기간 동안 국내 도소매기업의 성과를 분석하는 것이다. 기업성과에 대한 변수로는 운영효율성 (Operational efficiency)을 선택하였으며, 확률변경분석 (Stochastic frontier analysis)을 통해 운영효율성을 추정하였다. 이후 운영효율성에 미치는 코로나19 기간 (2020년1~2분기)의 효과를 살펴보기 위해 해당 기간의 분기별 고정효과 (Quarterly fixed effect)를 회귀분석을 통해 검토하였다. 본 연구의 주요 결과는 다음과 같다. 첫째, 분석 기간 (2019년 1분기~2020년 2분기) 동안 운영효율성의 평균적 수준은 대략 0.7138이었다. 둘째, 운영효율성에 대한 코로나 19 기간 (2020년 1분기~2분기)의 고정효과는 유의미하지 않았다. 셋째, 운영효율성과 기업규모 사이의 정의 결과를 확인하였다. 한편 본 연구는 운영효율성이라는 기업차원의 성과변수와 코로나19 기간이라는 거시경제적 변수의 관련성을 검토하였다는 점에서 의미가 있다고 볼 수 있다.

• Journal of Preventive Medicine and Public Health
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• 제56권4호
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• pp.312-318
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• 2023

Objectives: We reviewed the operational definitions of colorectal cancer (CRC) from studies using the Korean National Health Insurance Service (NHIS) and compared CRC incidence derived from the commonly used operational definitions in the literature with the statistics reported by the Korea Central Cancer Registry (KCCR). Methods: We searched the MEDLINE and KoreaMed databases to identify studies containing operational definitions of CRC, published until January 15, 2021. All pertinent data concerning the study period, the utilized database, and the outcome variable were extracted. Within the NHIS-National Sample Cohort, age-standardized incidence rates (ASRs) of CRC were calculated for each operational definition found in the literature between 2005 and 2019. These rates were then compared with ASRs from the KCCR. Results: From the 62 eligible studies, 9 operational definitions for CRC were identified. The most commonly used operational definition was "C18-C20" (n=20), followed by "C18-C20 with claim code for treatment" (n=3) and "C18-C20 with V193 (code for registered cancer patients' payment deduction)" (n=3). The ASRs reported using these operational definitions were lower than the ASRs from KCCR, except for "C18-C20 used as the main diagnosis." The smallest difference in ASRs was observed for "C18-C20," followed by "C18-C20 with V193," and "C18-C20 with claim code for hospitalization or code for treatment." Conclusions: In defining CRC patients utilizing the NHIS database, the ASR derived through the operational definition of "C18-C20 as the main diagnosis" was comparable to the ASR from the KCCR. Depending on the study hypothesis, operational definitions using treatment codes may be utilized.

• Transactions on Electrical and Electronic Materials
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• 제9권6호
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• pp.260-264
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• 2008

The operational characteristics of superconducting amplifier using vortex flux flow were analyzed from an equivalent circuit in which its current-voltage characteristics for the vortex motion in YBCO microbridge were reflected. For the analysis of operation as an amplifier, dc bias operational point for the superconducting amplifier is determined and then ac operational characteristics for the designed superconducting amplifier were investigated. The variation of transresistance, which describes the operational characteristics of superconducting amplifier, was estimated with respect to conditions of dc bias. The current and the voltage gains, which can be derived from the circuit for small signal analysis, were calculated at each operational point and compared with the results obtained from the numerical analysis for the small signal circuit. From our paper, the characteristics of amplification for superconducting flux flow transistor (SFFT) could be confirmed. The development of the superconducting amplifier applicable to various devices is expected.

• 전기학회논문지P
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• 제53권4호
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• pp.175-182
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• 2004

This paper presents a new method for finding the Block Pulse series coefficients, deriving the Block Pulse integration operational matrices and generalizing the integration operational matrices which are necessary for the control fields using the Block Pulse functions. In order to apply the Block Pulse function technique to the problems of state estimation or parameter identification more efficiently, it is necessary to find the more exact value of the Block Pulse series coefficients and integral operational matrices. This paper presents the method for improving the accuracy of the Block Pulse series coefficients and derives generalized integration operational matrix and applied the matrix to the analysis of linear time-invariant system.