• Journal of Pharmaceutical Investigation
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• v.37 no.1
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• pp.27-37
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• 2007

Proficiency test is an essential tool far ensuring analytical ability of analytical chemists and analytical institutes. Usually, the standard protocol for proficiency test is focused on acceptability of reported analytical results of participants by calculating z-scores and related diagnostic parameters. The ultimate goal of this process is to reveal the sources of variability of analytical results and to find the way to reduce their influence. In this study, the method of analysis of variance (ANOVA) was applied to the analytical data collected from qualify control departments of pharmaceutical companies in KyungIn province in Korea in the year of 2000. As influencing factors of variability of analytical results, the use of internal standards for liquid and gas chromatograpy, the educational and professional background of participants, geological locations and yearly production sizes of participating companies were evaluated. To evaluate the variability in accuracy of analytical results, absolute differences from sample mean and sample median were used and to evaluate variability in precision of individual participants, the reported standard deviation of each participant was used. As a result, the use of internal standards in gas chromatographic analysis, participants' academic background and the yearly production sizes of pharmaceutical companies showed statistically significant influence to the accuracy and the precision of the reported analytical results used in this study.

• KSBB Journal
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• v.32 no.1
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• pp.54-62
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• 2017

This study aimed to estimate the measurement uncertainty related to determination of hyaluronic acid used as a dietary supplement by high-performance liquid chromatography. According to the guidelines of the Association of Official Analytical Chemists, the analytical processes for determination of hyaluronic acid were performed. And the measurement uncertainty obtained during the analytical processes were expressed in accordance with mathematical/ statistical guidances of GUM (Guide to the Expression of Uncertainty in Measurement) & EURACHEM (Focus for Analytical Chemistry in Europe) for the analytical operations. For the uncertainty in measurement produced based on this analytical method, the expanded uncertainty was calculated by using the relative standard uncertainty between analytical results and sources of uncertainty in measurement (sample weight, final volume, extraction volume, standard solution, matrix and instrument etc). In the results of 95% confidence interval, it was calculated that the uncertainty in measurement was $57.75{\pm}8.76{\mu}g/kg$ (k=2.0). Therefore, it showed that the measurement uncertainty obtained by this analytical method influences on 15.2% of the contents of hyaluronic acid as the analytical results.

• Journal of Electrical Engineering and Technology
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• v.2 no.2
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• pp.221-230
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• 2007

This paper deals with analytical prediction for electromagnetic characteristics of a tubular linear actuator with Halbach array using transfer relations, namely, Melcher's methodology. Using transfer relations derived in terms of magnetic vector potential and a two-dimensional (2-d) cylindrical coordinate system, this paper derives analytical solutions for magnetic vector potential due to permanent magnets (PMs) and stator winding currents. On the basis of these analytical solutions, this paper also achieves analytical solutions for the magnetic fields distribution produced by PMs, stator windings current and axial thrust. The analytical results are validated extensively by finite element (FE) analyses. In particular, test results such as thrust measurements are given to confirm the analysis. Finally, this paper estimates control parameters using analytical solutions and test results such as thrust, back-emf, inductance and resistance measurements.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.29B no.1
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• pp.11-17
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• 1992

This paper is to propose an analytical queuing model for parallel processing of sequential program with nested loops. The analytical results are compared with the results from the implemented multiprocessor system composed of four intel 8088 microprocessor, eight 2KB shared common memories, and a hardware token ring. At results, this study shows that the processed results are almost similar in proposed analytical model and real system. Proposed analytical model can be applied to evaluate parallel processing of sequential program with nested loops.

• Journal of Electrical Engineering and Technology
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• v.12 no.2
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• pp.769-777
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• 2017

The research of air gap flux density has a significant effect on predicting and optimizing the structure parameters of electrical machines. In the paper, the air gap coefficient, leakage flux factor and saturation coefficient are first analytically expressed in terms of motor properties and structure parameters. Subsequently, the analytical model of average air gap flux density for surface-mounted permanent magnet synchronous machines is proposed with considering slotting effect and saturation. In order to verify the accuracy of the proposed analytical model, the experiment and finite element analysis (FEA) are used. It shows that the analytical results keep consistency well with the experimental result and FEA results, and the errors between FEA results and analytical results are less than 5% for SPM with high power. Finally, the analytical model is applied to optimizing the motor structure parameters. The optimal results indicate that the analytical calculation model provides a great potential to the machine design and optimization.

• Computers and Concrete
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• v.25 no.5
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• pp.461-470
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• 2020

This paper presents a numerical study on structural behavior of hammer head pier cap beams, extended on verges and reinforced with carbon fiber reinforced polymer (CFRP) plates. A 3-D finite element (FE) model along with a simplified analytical model are presented. Concrete damage plasticity (CDP) was adapted in the FE model and an analytical approach predicting the CFRP anchor strength was adapted in both FE and analytical model. Total five quarter-scaled pier cap beams with various CFRP reinforcing schemes were experimentally tested and analyzed with numerical approaches. Comparison between experimental results, FE results, analytical results and current ACI guideline predictions was presented. The FE results showed good agreement with experimental results in terms of failure mode, ultimate capacity, load-displacement response and strain distribution. In addition, the proposed strut-and-tie based analytical model provides the most accurate prediction of ultimate strength of extended cap beams among the three numerical approaches.

• Architectural research
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• v.19 no.3
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• pp.79-87
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• 2017

In earthquake engineering, dynamic analyses are usually conducted by using a nonlinear analytical model of the entire building in order to identify the performance against earthquakes. At the same time, a large number of dynamic analyses are required to consider uncertainties on analytical models and ground motions. Therefore, it is necessary for the analytical model to be adequate, that is to say, the runtime should not be too long as the entire building is modeled to be in much detail, or the nonlinear model should not yield outputs very far from the actual ones by excluding important behaviors too much. The analytical model is usually developed based on experimental results, which have been already conducted for reinforced concrete columns with relaxed details. Therefore, this study aimed at making analytical models to be able to simulate the hysteretic behavior of the columns simply and easily. The analytical model utilizes a lumped hinge model to represent nonlinear moment-rotation hysteretic behavior of RC columns, which is feasible for nonlinear dynamic analyses usually conducted in earthquake engineering and for matching the analytical model to test results. For the analytical model, elements and material models provided by OpenSees are utilized. The analytical model can define the envelope curve, pinching, and unloading stiffness deterioration, but shortcoming of this model is not to be able to consider axial force-moment interaction directly and to simulate strength deterioration after post-capping completely. However, the analytical model can still represent test results well by considering that the goal of this study is to propose a general way to represent the hysteretic behavior of RC columns with relaxed details, not to provide parameters for a refined hysteretic model that can be just applied case by case.

• International Journal of Highway Engineering
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• v.18 no.3
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• pp.21-32
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• 2016

PURPOSES : In this paper, the analytical solutions suggested to simulate the behavior of rheological fluids were rigorously re-derived and investigated for fixed conditions to evaluate the applicability for the solutions on a mini-cone slump test of cement paste. The selected solutions with proper boundary conditions can be used as reference solutions to evaluate the performance of numerical simulation approaches, such as the discrete element method. METHODS : The slump, height, and spread radius for the given boundary and yield stress conditions that are determined by five different analytical solutions are compared. RESULTS : The analytical solution based on fluid mechanics for pure shear flow shows similar results to that for intermediate flow at low yield stresses. The fluid mechanics-based analytical solution resulted in a very similar trend to the geometry-based analytical solution. However, it showed a higher slump at high yield stress and lower slump at low yield stress ranges than the geometry-based analytical model. The analytical solution based on the mini-cone geometry was not significantly affected by the yield criteria, such as von Mises and Tresca. CONCLUSIONS : Even though differences among the analytical solutions in terms of slump and spread radius existed, the difference can be considered insignificant when the solutions were used as reference to evaluate the appropriateness of numerical approaches, such as the discrete element method.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.3
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• pp.539-546
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• 1997

In this paper, we proposed a new mehtod to analyze the performance degradation by timing jitters in the APD (avalanche photodiode) receivers of intensity modulation/direct detection digital optical communication systems where raised cosine pulse-shaping filters are used to reduce the effect of noise while minimizing intersymbol interferences. The proposed analytical method is an extension of an analytical method we have already developed for pin diode receivers, and incorporates the effects of APD's multiplication factor and resulting shot noise. Using the proposed analytical method, we derive an approximated power penalty due to timing jitters based on an assumption of Gaussian distribution for timing jitters, and compare with that of the conventional analytical method. The results obtained from the proposed analytical method show that conventional analytical methods underestimate the influence of timing jitters on the reciver performance. The results also show that APD's multiplication factor which optimizes receiver sensitivity is smaller than that obtained by the conventional analytical method.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2005.04a
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• pp.448-455
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• 2005

In this paper, an analytical model for estimation of the time at which the concrete surface begins to dry is introduced to predict whether or not plastic shrinkage cracks occur. First of all, the validity of a consolidation model for bleeding of cement paste proposed by Tan et al. is verified by comparing the analytical results with the experimental results, and used to evaluate the rate and amount of bleed water of concrete. Also an analytical model for evaporation of bleed water which considers the effect of the temperature variation of concrete surface due to hydration heat on the evaporation rate is proposed, and the experimental and analytical results are then compared to verify the validity of the introduced model. In advance, the time at which the concrete surface begins to dry is estimated using above two analytical models, and compared with the experimental results about the time at which plastic shrinkage cracks occur. From the comparison, it is verified that the proposed model can predict the occurrence of plastic shrinkage cracking with comparative precision.