• 한국산림과학회지
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• 제99권6호
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• pp.929-933
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• 2010

본 연구의 목적은 우리나라 대표 수종인 소나무(Pinus densiflora)의 정확한 용적밀도(Basic wood density)를 산출하고, 용적밀도의 불확도(Uncertainty)를 평가하는데 있다. 소나무림의 지역적인 분포 차이를 고려하여 강원지방 소나무와 중부지방소나무로 구분하였으며, 전국적으로 총 33개소의 조사구를 선정한 후, 각 조사구를 대표하는 표본목을 채취하여 분석하였다. 용적밀도의 경우, IPCC 기준임령에 따른 20년생 이전의 유령림과 21년생 이후의 성숙림 간에 통계적인 유의성이 나타나지 않은 반면, 강원지방소나무와 중부지방소나무간의 지역적인 차이에서는 통계적인 유의성(p-value=0.0017)이 나타났다. 강원지방소나무의 용적밀도와 불확도는 0.396(g/$cm^3$)과 12.9(%)로 산출된 반면에, 중부지방소나무는 각각 0.470(g/$cm^3$)과 3.8(%)로 나타났다. 따라서 본 연구에서 제시된 소나무의 용적밀도에 대한 불확도는 IPCC(2006)가 권장하는 불확도의 범위보다 훨씬 더 정밀한 값을 나타내었다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 A
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• pp.199-201
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• 2005

This paper proposes a method to evaluate the TTC by considering uncertainty of weather. Impact of the contingency on the system performance could not be addressed in a deterministic way because of the random nature of the system equipment outage and the increase of outage probability according to weather condition. For this reasons, probabilistic approach is necessary to realize evaluation of TTC. This method uses a sequential MCS. In sequential simulation, the chronological behavior of the system is simulated by sampling sequence of the system operating states based on the probability distribution of the component state duration. Therefor, MCS is used to accomplish the probabilistic calculation of TTC with consideration of weather condition.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2008년도 추계학술발표대회 논문집
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• pp.161-166
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• 2008

The major purpose of this paper is to develop an uncertainty estimate for the calibration of thermopile instruments used to measure solar radiation parameters. We briefly describe the solar radiation parameters most often measured, instrumentation, reference standards, and calibration techniques. The bulk of the paper describes elemental sources of error and their magnitude. We then apply a standard error analysis methodology to combine these elemental error estimates into a statement of total uncertainty for the instrument calibration factor. Our results allow one to evaluate the accuracy of a radiometric measurement using thermopile instrumentation in the light of the application, such as engineering test evaluation or for validation of theoretical models.

• 산업경영시스템학회지
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• 제22권51호
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• pp.63-72
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• 1999

Many firms have applied flexible manufacturing systems as a means of increasing productivity, profitability, and quality. Therefore, the purpose of this paper is to develop the more efficient justification model through an analytical scoring model with the quantitative factors, flexibility factors, and safety factors under uncertainty. In this paper, the three factors for properly comparing and evaluating of flexible manufacturing systems are presented. Especially, this paper has emphasized the flexibility and safety factor; the one consists of organization assessment, process treatment function, products and products quantity, useful life assesment, and software function, the other presents risk assesment, Y2K problem, safety device analysis, total productive management system, safety management. Finally, a normalized scoring model by the new flexibility and safety factors can be used in real fields for flexible manufacturing systems project selection under uncertainty.

• Journal of the Optical Society of Korea
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• 제16권4호
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• pp.396-400
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• 2012

We introduce a combined technique and the mathematical description for distance measurements using a femtosecond pulse laser in a long range and a fine resolution. For distance measurements, the maximum measurable range can be extended by combining measurement results from several different methods while requiring relationships between the different measurement uncertainties and unambiguity ranges. This paper briefly explains why the uncertainty of a rough measurement technique (RMT) should be, at least, smaller than the half unambiguity range of a fine measurement technique (FMT) in order to combine a FMT with a RMT. Further discussions about the total measurement range, resolution, and uncertainty for various optical measurement techniques are also discussed.

• International Journal of Computer Science & Network Security
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• 제22권8호
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• pp.45-54
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• 2022

In this study, a multi-objective robust job-shop scheduling (JSS) model was developed. The model considered multi-jobs and multi-machines. The model also considered uncertain processing times for all tasks. Each job was assigned a specific due date and a tardiness penalty to be paid if the job was not delivered on time. If any job was completed early, holding expenses would be assigned. In addition, the model added idling penalties to accommodate the idling of machines while waiting for jobs. The problem assigned was to determine the optimal start times for each task that would minimize the expected penalties. A numerical problem was solved to minimize both the makespan and the total penalties, and a comparison was made between the results. Analysis of the results produced a prescription for optimizing penalties that is important to be accounted for in conjunction with uncertainties in the job-shop scheduling problem (JSSP).

• 대한환경공학회지
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• 제30권11호
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• pp.1123-1131
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• 2008

본 연구는 대기 중 PM2.5의 미량금속 중 As을 중성자방사화분석법을 이용하여 분석할 때 발생되는 측정불확도를 ISO GUM 방법과 MCS 방법을 모두 적용하여 비교, 평가하였다. 불확도의 요인은 ISO GUM을 엄격하게 준용하여 파악하였으며 특정일에 채취된 PM2.5 내 As 농도에 대해 두 방법의 계산 결과가 4% 미만으로 크게 다르지 않는 것으로 나타났다. 연구기간 중 채취된 총 60개의 PM2.5 시료에 대해 As 농도의 확장불확도를 역시 MCS 방법을 이용하여 산출하였는데, 연구지역에서의 As의 개별 농도값에 대한 95% 신뢰구간의 확장불확도는 대부분 10%의 범위에서 존재하는 것으로 나타났다. 확장불확도에 대한 표준불확도 요인의 기여율은 계측통계오차(62.3%), 검출효율(18.5%), 시료 채취 시 유량(12.3%), flux 변동(2.3%), 특정감마선 방출률(1.8%) 등의 순으로 크게 나타났다.

• 한국항해항만학회지
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• 제33권7호
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• pp.469-476
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• 2009

Recent collapse of shipping market right after unprecedent surge clearly demonstrates that shipping industry is extremely risky. Due to the volatile movements of the freight rates, investors tend to ask higher rate of return; higher required return reduces the total net present value of the investment project. For several decades, the Discounted Cash Flow(DCF hereafter) analysis has been the most frequently used valuation technique. However, the main problem of the DCF analysis is its assumption that the discount rate would stay the same during the project life. In other words, it usually does not address the decisions that managers have after a project has been accepted. The purpose of this study is investigate a new valuation method of investment: the Real Option Analysis(ROA hereafter) on ship investment. By replacing the existing valuation methods with the new one, the research will present a new perspective on investment with uncertainty. While uncertainty increases risk of investment and consequently discounts the value of it in the traditional feasibility analysis, in the ROA, a new valuation method which will be addressed in the research, uncertainty means some additional value of flexibility so that the tool can help investors produce more accurate decisions. Contrary to the DCF analysis, the ROA takes managerial flexibilities into account. In reality, capital budgeting and project management is typically dynamic, rather than static in nature. The ROA finds and assesses the values of managerial flexibilities or real options in the investments. The main structures of the research will be as follows: (1) overview of the ship investment project, (2) evaluation of the project by the Net Present Value analysis, (3) evaluation of the same project by the Real Option Analysis, (4) comparision of the two techniques.

• Journal of Information Technology Applications and Management
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• 제27권6호
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• pp.53-73
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• 2020

Many prior studies have been conducted that positive reviews increase the intention to purchase. However, there are very few papers that have studied the impact of review search on purchase satisfaction. It is meaningful to study the impact of review search on purchase satisfaction as it can lead the business successfully by inducing repurchase. There is also no study of how review search have different effects on purchase satisfaction among countries. Given the growing number of cross-border e-commerce, we believe that the need for research is high because identifying these differences between countries can have a very important impact on a company's successful overseas expansion. Therefore, in this study, the impact of positive and negative review search on purchase satisfaction and the national impact were set up as a research model. In order to verify this research model, the survey was distributed to those who experienced online purchase in Korea and China, and a total of 234 copies were collected, including 125 copies in Korea, 109 copies in China, and the research model was verified using Smart-PLS structural equation analysis tools. First, positive review search has been shown to positively affect purchase satisfaction. Second, it has been shown that negative review search also has a positive effect on purchase satisfaction. Third, the impact of positive and negative review search on purchase satisfaction was different between Korea and China. While Korea is more aggressive in review search than China due to its high tendency to avoid uncertainty, China is less likely to avoid uncertainty than Korea and is more likely to rely on brand familiarity. Therefore, according to the uncertainty avoidance moderation effect the impact of positive and negative review search on purchase satisfaction was higher in Korea than in China. In this study, Shopping mall managers need to take strategic measures to maximize shopping mall performance by recognizing positive aspects of negative review search on purchase satisfaction. Companies and managers in Korea and China can establish strategies to promote product sales when companies enter the global market.

• 대기
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• 제30권4호
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• pp.361-376
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• 2020

This study evaluates multiple Regional Climate Models (RCMs) in simulating temperature and precipitation over the Far East Asia (FEA) and estimates the portions of the total uncertainty originating in the RCMs and the driving Global Climate Models (GCMs) using nine present-day (1981~2000) climate data obtained from combinations of three GCMs and three RCMs in the CORDEX-EA phase2. Downscaling using the RCMs generally improves the present temperature and precipitation simulated in the GCMs. The mean temperature climate in the RCM simulations is similar to that in the GCMs; however, RCMs yield notably better spatial variability than the GCMs. In particular, the RCMs generally yield positive added values to the variability of the summer temperature and the winter precipitation. Evaluating the uncertainties by the GCMs (VARGCM) and the RCMs (VARRCM) on the basis of two-way ANOVA shows that VARRCM is greater than VARGCM in contrast to previous studies which showed VARGCM is larger. In particular, in the winter temperature, the ocean has a very large VARRCM of up to 30%. Precipitation shows that VARRCM is greater than VARGCM in all seasons, but the difference is insignificant. In the following study, we will analyze how the uncertainty of the climate model in the present-day period affects future climate change prospects.