• Analytical Science and Technology
• /
• v.25 no.1
• /
• pp.83-90
• /
• 2012

The objective of the study was to estimate the measurement uncertainty associated with determination of creatinine (Cr) in urine samples by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Centrifuged urine samples (10 ${\mu}L$) were diluted with 390 ${\mu}L$ of distilled water. To 20 ${\mu}L$ aliquots of diluted urine samples, 30 ${\mu}L$ of internal standard solution (Cr-$d_3$, 5 ${\mu}g/mL$) and 10 ${\mu}L$ of acetonitrile were added and filtered. The samples (1 ${\mu}L$) were introduced into LC-MS/MS with no further pretreatment. Cr was separated on a multi-mode ODS column (Scherzo SM-C18, 75 ${\times}$ 2.0 mm I.D., 3 ${\mu}m$) and quantified by LC-MS/MS operating in MRM mode (Cr, m/z 114.0${\rightarrow}$ 86.0; Cr-$d_3$, m/z 117.0${\rightarrow}$ 89.1). The four factors that contribute uncertainty to the final result were extracted and evaluated. The principal factors of contribution to combined standard uncertainty were sample dilution, calibration curve and repeatability, while the preparation of standard solution was only a minor factor. Relative extended uncertainty of the measured concentration was 14.2% in a real urine sample.

• Journal of Environmental Health Sciences
• /
• v.30 no.3
• /
• pp.221-229
• /
• 2004

We estimated decreasing rate of indoor air pollutants which are PM10 and $NO_2$ by the air cleaner in indoor environment. This study respectively examined concentration of PM10 and $NO_2$ two times in 34 sites located in Seoul and Kyung-gi Do from April to September in 2003. Sectional period was respectively divided for operating the air cleaner and non-operating the air cleaner. Moreover, questionnaire was executed to grasp physical characteristic of objective building and residential characteristic of residents by using method of self-entry. There was a trend that concentration of PM10 and $NO_2$ separated number of residents during operating period respectively decreased among indoor air. According to the existence of smoker in indoor, both concentration of PM10 and $NO_2$ during operating period decreased in each case, and according to existence of pets, both cases decreased concentration of pollutants by operating the air cleaner. We used Monte-Calro simulation to remove uncertainty and identify efficiency of eliminated pollutants such as PM10 and $NO_2$ by the air cleaner. Average efficiency of removal for PM10 and $NO_2$ were 61.84${\pm}$23.04% and 48.67${\pm}$18.03% respectively.

• Korean Institute of Interior Design Journal
• /
• v.17 no.1
• /
• pp.77-83
• /
• 2008

MVRDV is most important architect as created interesting architectural space in contemporary architecture, and so they applies to the unique theory in their architecture. They used to architectural diagram, program, datascape, density as a design tool. Especially, they have create new architectural space and form in using architectural diagram, program, datascape, density, and void. So, this study is purposed to explain how they use as architectural tool to make composition of it's architectural space and is purpose to explain what is their main concept in architectural space. MVRDV's architectural space has fundamental methodology. That is Datascape on uncertainty and continuity between urban space and architectural space. The former consist in using diagram and architectural program and the latter consist in operating architectural void and inner continuity surface. The conclusion is follows 1. The mode of spacial composition by architectural void is correspond density of city as MVRDV's architectural thinking. 2. The mode of spacial composition by architectural program is ambiguous to the boundary between inner and exterior space by transparency. 3. The mode of spacial composition by architectural diagram make to generate the architectural form and space, through the reinterpretation and relocation of architectural program. 4. The mode of spacial composition inner continuity plane is make relative between site and inner space.

• The Transactions of the Korean Institute of Electrical Engineers A
• /
• v.55 no.1
• /
• pp.45-51
• /
• 2006

This paper proposes a method to evaluate the Total Transfer Capability (TTC) by considering uncertainty of weather conditions. TTC is limited not only by the violation of system thermal and voltage limits, but also restricted by transient stability limit. Impact of the contingency on the power 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 the weather conditions. For these reasons, probabilistic approach is necessary to realize evaluation of the TTC. This method uses a sequential Monte Carlo simulation (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. Therefore, MCS is used to accomplish the probabilistic calculation of the TTC with consideration of the weather conditions.

• Journal of the Korean Society of Systems Engineering
• /
• v.19 no.2
• /
• pp.32-45
• /
• 2023

Implementing Severe Accident Management (SAM) strategies is crucial for enhancing a nuclear power plant's resilience and safety against severe accidents conditions represented in the analysis of Station Blackout (SBO) event. Among these critical approaches, the In-Vessel Retention (IVR) through External Reactor Vessel Cooling (IVR-ERVC) strategy plays a key role in preventing vessel failure. This work is designed to evaluate the efficacy of the IVR strategy for a high-power density reactor APR1400. The APR1400's plant is represented and simulated under steady-state and transient conditions for a station blackout (SBO) accident scenario using the computer code, ASYST. The APR1400's thermal-hydraulic response is analyzed to assess its performance as it progresses toward a severe accident scenario during an extended SBO. The effectiveness of emergency operating procedures (EOPs) and severe accident management guidelines (SAMGs) are systematically examined to assess their ability to mitigate the accident. A group of associated key phenomena selected based on Phenomenon Identification and Ranking Tables (PIRT) and uncertain parameters are identified accordingly and then propagated within DAKOTA Uncertainty Quantification (UQ) framework until a statistically representative sample is obtained and hence determine the uncertainty bands of key system parameters. The Systems Engineering methodology is applied to direct the progression of work, ensuring systematic and efficient execution.

• Journal of Climate Change Research
• /
• v.7 no.3
• /
• pp.325-334
• /
• 2016

We projected the distribution of Hedera rhombea, an evergreen broad-leaved climbing plant, under current climate conditions and predicted its future distributions under global warming. Inaddition, weexplained model uncertainty by employing 9 single Species Distribution model (SDM)s to model the distribution of Hedera rhombea. 9 single SDMs were constructed with 736 presence/absence data and 3 temperature and 3 precipitation data. Uncertainty of each SDM was assessed with TSS (Ture Skill Statistics) and AUC (the Area under the curve) value of ROC (receiver operating characteristic) analyses. To reduce model uncertainty, we combined 9 single SDMs weighted by TSS and resulted in an ensemble forecast, a TSS weighted ensemble. We predicted future distributions of Hedera rhombea under future climate conditions for the period of 2050 (2040~2060), which were estimated with HadGEM2-AO. RF (Random Forest), GBM (Generalized Boosted Model) and TSS weighted ensemble model showed higher prediction accuracies (AUC > 0.95, TSS > 0.80) than other SDMs. Based on the projections of TSS weighted ensemble, potential habitats under current climate conditions showed a discrepancy with actual habitats, especially in the northern distribution limit. The observed northern boundary of Hedera rhombea is Ulsan in the eastern Korean Peninsula, but the projected limit was eastern coast of Gangwon province. Geomorphological conditions and the dispersal limitations mediated by birds, the lack of bird habitats at eastern coast of Gangwon Province, account for such discrepancy. In general, potential habitats of Hedera rhombea expanded under future climate conditions, but the extent of expansions depend on RCP scenarios. Potential Habitat of Hedera rhombea expanded into Jeolla-inland area under RCP 4.5, and into Chungnam and Wonsan under RCP 8.5. Our results would be fundamental information for understanding the potential effects of climate change on the distribution of Hedera rhombea.

• Journal of Climate Change Research
• /
• v.9 no.2
• /
• pp.143-156
• /
• 2018

Evapotranspiration is a key element in designing and operating agricultural hydraulic structures. The profound effect of climate change to local agro-hydrological systems makes it inevitable to study the potential variability in evapotranspiration rate in order to develop policies on future agricultural water management as well as to evaluate changes in agricultural environment. The APEX-Paddy model was used to simulate local evapotranspiration responses to climate change scenarios. Nine Global Climate Models(GCMs) downscaled using a non-parametric quantile mapping method and a Multi?Model Ensemble method(MME) were used for an uncertainty analysis in the climate scenarios. Results indicate that APEX-Paddy and the downscaled 9 GCMs reproduce evapotranspiration accurately for historical period(1976~2005). For future periods, simulated evapotranspiration rate under the RCP 4.5 scenario showed increasing trends by -1.31%, 2.21% and 4.32% for 2025s(2011~2040), 2055s(2041~2070) and 2085s(2071~2100), respectively, compared with historical(441.6 mm). Similar trends were found under the RCP 8.5 scenario with the rates of increase by 0.00%, 4.67%, and 7.41% for the near?term, mid?term, and long?term periods. Monthly evapotranspiration was predicted to be the highest in August, July was the month having a strong upward trend while. September and October were the months showing downward trends in evapotranspiration are mainly resulted from the shortening of the growth period of paddy rice due to temperature increase and stomatal closer as ambient $CO_2$ concentration increases in the future.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
• /
• v.12 no.5
• /
• pp.117-126
• /
• 2017

This study analyzed both the effect small and medium-sized suppliers' SCM capacity on the performance and how the moderating effect of demand uncertainty as an environmental factor affects this relation. The study is based on the data collected from the survey of small and medium-sized suppliers operating in electronics, metal, machinery, automobile, and textile. It analyzed the results of survey targeting suppliers of these areas by using structure equation modeling. According to the analyzed result, the relation capital of small and medium-sized supplier affects the performance, but there is no relation between coordination capability and the performance. In case of the moderating effect of demand uncertainty, while there is a positive moderating effect of demand uncertainty between relation capital and performance, there is no any moderating effect between coordination capability and performance. It turns out that the relation capital keep having a positive effect on the performance even if there is a demand uncertainty.

• Journal of Navigation and Port Research
• /
• v.40 no.3
• /
• pp.129-138
• /
• 2016

Shipping companies involved in sea transportation service are exposed to uncertainty due to its volatile business environment. It is crucial that shipping companies take effective strategies to cope with uncertain business environments and to achieve high business performance. Using Porter's generic strategy, this study investigates the relationships between environmental uncertainty and competitive strategies, and the impact of competitive strategies on firm's business performance. To test hypotheses, OLS regressions and Tobit analysis were conducted on Korea shipping companies who provide global sea transportation service. The findings of this study can be summarized as follows. First, variation of environmental uncertainty affects cost-leadership strategy and differentiation strategy. Diversity of environmental uncertainty affects differentiation strategy, but not cost-leadership strategy. Second, firms attain business performance by using the cost-leadership strategy. That is, shipping companies can achieve high business performance by reducing their operating costs in the entire process of transportation service.

• Information Systems Review
• /
• v.11 no.3
• /
• pp.125-146
• /
• 2009

The emergence of open source software(OSS) with its most prominent advantages creates a vast interest among practitioners. A study on Linux, the most well-known OSS, estimated that it would cost as 5.4 billion Euros taking over 73,000 person-years if it had been developed by conventional means. However, Linux has achieved only 0.65 percent of the operating system market for individual users while Microsoft windows family counts for nearly 90 percent of the market. Much of the effort being spent in the development of OSS is going to waste and potential value that OSS can bring to users is not being realized. Adoption of OSS is often accompanied by the discontinuance of existing software that is already in place. If users resist changing, they may not adopt OSS. Using the case of Linux, this study examines user resistance to change from the commercial operating software to the free operating system. This study identifies six sub-types of switching costs (uncertainty, emotional, setup, learning, lost benefit, and sunk costs) and tests their effects on user resistance to change based on a survey of 201 users. The results show that user resistance to change has a negative impact on the adoption of OSS. Further, this study shows that uncertainty and emotional costs have significant effects on user resistance to change. Beyond previous research on technology adoption, this research contributes towards an understanding of the switching costs leading to user resistance to change and offers suggestions to OSS practitioners for developing strategies to improve the adoption of OSS.