• Nuclear Engineering and Technology
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• v.56 no.2
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• pp.451-462
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• 2024

In order to optimize the operational safety and reliability of the upper launcher for the CFETR ECRH system, a design of the launcher based on the remote steering concept is currently being carried out for comparison with the front steering equivalent. This paper presents the remote steering system's conceptual design and simulation analysis. A Square Corrugated Waveguide (SCW) of 65 × 65 mm has been designed with an optimized length of 9.35 m. By changing the relative length of the waveguide, the transmission efficiency of the SCW is optimized within the range of steering angles ±12°. Different error factors are investigated in detail, and corresponding acceptable error ranges are provided. Considering these error factors and ignoring ohmic losses and thermal effects, the relative transmission efficiency of the SCW is estimated to be >98 % within the steering angle range. A matching steering unit for the SCW is designed, which consists of an ellipsoidal focusing mirror and a steerable flat mirror. The detailed design of the steerable mirror motion trajectory is presented. Also, the influence of the possible beam incident errors caused by the steering unit on the transmission efficiency is analyzed in detail.

• Physical Therapy Rehabilitation Science
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• v.13 no.2
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• pp.143-151
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• 2024

Objective: This study aims to assess the test-retest reproducibility of the Short Form Berg Balance Scale (SF-BBS) and the Short Form Postural Assessment Scale for Stroke (SF-PASS) among chronic stroke survivors, focusing on their reliability for consistent measurements over time. Design: A cross-sectional study design Methods: Thirty chronic stroke survivors participated in this study, undergoing evaluations with SF-BBS and SF-PASS scales at two different points, separated by a seven-day interval. The analysis focused on test-retest reliability, employing statistical measures such as the Intra-Class Coefficient (ICC_2,1), Standard Error of Measurement (SEM), Minimal Detectable Change (MDC), and MDC%, the Bland-Altman plot to assess the limits of agreement and the extent of random measurement error. Results: The study found notable test-retest reproducibility for both SF-BBS and SF-PASS, with ICC values demonstrating strong reliability (0.932 to 0.941, with a confidence interval of 0.889 to 0.973). SEM values for SF-BBS and SF-PASS were reported as 1.34 and 0.61, respectively, indicating low measurement error. MDC values of 3.71 for SF-BBS and 1.69 for SF-PASS suggest that the scales have an acceptable level of sensitivity to change, with reliability metrics falling below 20% of the maximum possible score. Conclusions: The findings suggest that both SF-BBS and SF-PASS exhibit high intra-class correlation coefficients, indicating strong test-retest reliability. The SEM and MDC values further support the scales' reproducibility and reliability as tools for evaluating mobility and dynamic balance in chronic stroke survivors. Therefore, these scales are recommended for clinical use in this population, providing reliable measures for assessing progress in rehabilitation.

• Journal of Science Education
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• v.35 no.2
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• pp.127-137
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• 2011

The purpose of this study is to develop the analysis frame of reporting observation results by high school students in biology experiments using microscopes and analyze their error types. For this study, five experiments were carried out by 12 high school students in B metropolitan city. Before these experiments, developed the analysis frame of reporting observation results. Tests for checking prior knowledge of students were done and results of each experiment were taken picture of. Using the developed framework, the real results and reported results submitted by students were analyzed. The result of this study shows how students report their observation results and they tend to have difficulty in doing observation activity itself. The ratio of factual reports is low because observation ways and recording ways have not been taught properly. Observation training is needed for observing real results objectively. The improvement in experiment environment is necessary for right observation, not observation for checking based on only results. In addition, the education of ethics in science research focusing on the integrity should be performed. The analysis data of reporting observation result by students can be used as basic data for teachers to plan observation strategies and to have right observation views and ways.

• Journal of the Korean Society of Marine Environment & Safety
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• v.23 no.7
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• pp.801-809
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• 2017

The purpose of this study is to contribute to the prevention of ship collisions by investigating real ship collision cases and statistically analyzing causes of human error for captains and Officers of the Watch (OOW). This study encompassed a total of 109 cases for 218 vessels, which were suitable for the analysis of ship accidents between merchant ships or merchant ships and fishing boats over the 7 years from 2010 to 2016. Data was collected while classifying vessels according to type, Give-way and Stand-on vessels, along with the cause of human error. Factors causing human error were identified after focusing on the cause of each collision given by the OOW ; frequency and cross tabulation analyses were conducted using SPSS, a statistical analysis tool. As a result, the main causes of human error by an OOW in a ship collision situation were that lookout was neglected in a Give-way vessel including radar surveillance (74.3 %) or continuous observation of an opponent vessel was carried out (17.4 %). A major factor for Stand-on vessels was failure to act to avoid collision with another vessel (63.3 %). In particular, most neglect for lookout type merchant ships occurred after the opponent ship was first observed, and a common cause of lookout neglect and neglect of duty was a focus on other tasks during navigational watch time.

• Journal of the Korea Safety Management & Science
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• v.10 no.2
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• pp.217-223
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• 2008

Measurement is used for evaluation of product or process exactly. If it couldn't measured correctly, Quality-cost must be raised and it would be hard to improve product quality. So, this study suggests improvement guide line for the multilateral problems of measuring instrument operation based on the investigation of 157 small and medium-sized enterprises in February, 2008. To use inspection gig correctly, man who treat it must be accustomed with the structure, the performance, the method. The inspection gig is selected properly for the measurement goal. If not, results couldn't be correctly or wasted time, efforts, and costs. When selecting a inspection gig, the locating, the clamping, and the efficiency must be considered.

• Bulletin of the Korean Chemical Society
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• v.24 no.6
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• pp.733-738
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• 2003

Linear scaling quantum theories are reviewed especially focusing on the method adopted in GAMESS. The three key translation equations of the fast multipole method (FMM) are deduced from the general polypolar expansions given earlier by Steinborn and Ruedenberg. Simplifications are introduced for the rotation-based FMM that lead to a very compact FMM formalism. The OPS (optimum parameter searching) procedure, a stable and efficient way of obtaining the optimum set of FMM parameters, is established with complete control over the tolerable error ε. In addition, a new parallel FMM algorithm, requiring virtually no inter-node communication, is suggested which is suitable for the parallel construction of Fock matrices in electronic structure calculations.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.05a
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• pp.213-216
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• 2005

Active control method is applied to a flexible beam excited by a shock impulse by focusing on reducing the residual vibrations after the shock input. It is assumed that the shock input can be measured and is always occurred on the same point of the beam. If the system is well identified and the corresponding inverse system is designed reliably, it has shown that a very simple feed-forward active control method may be applied to suppress the residual vibrations without using an error sensor and adaptive algorithm. Both numerical simulation and experimental result show a promising possibility of applying to a practical problem.

• MALSORI
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• no.56
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• pp.195-206
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• 2005

Discrimination between speech and music is important in many multimedia applications. In this paper, focusing on the spectral change characteristics of speech and music, we propose a new method of speech/music discrimination based on cepstral distance. Instead of using cepstral distance between the frames with fixed interval, the minimum of cepstral distances among neighbor frames is employed to increase discriminability between fast changing music and speech. And, to prevent misclassification of speech segments including short pause into music, short pause segments are excluded from computing cepstral distance. The experimental results show that proposed method yields the error rate reduction of$68\%$, in comparison with the conventional approach using cepstral distance.

• Journal of Korean Institute of Industrial Engineers
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• v.27 no.3
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• pp.297-304
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• 2001

Procurement decisions for inspection equipment are often made heavily based on the initial purchase price instead of the effects of inspection cost, equipment calibration and utilization over the lifetime. Cost of ownership(COO) models that take into account all of these cost factors together have been developed focusing on a single quality characteristic. In modern manufacturing environment, inspection equipment often can deal with more than one quality characteristic simultaneously. In this paper, we propose the revised COO model for the economic evaluation of the inspection equipment that can accommodate multiple quality characteristics. We also employ an engineering economy model to compare equipments with different life span. Software is developed for handy comparison of the COO of alternative equipments along with sensitivity analysis far the optimal procurement decision.

• Journal of Korean Society for Quality Management
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• v.36 no.4
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• pp.93-101
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• 2008

The rare metals, used for semiconductors, PDP-LCS and other specialized metal areas necessarily, has been playing a key role for the Korean economic development. Rare metals are influenced by exogenous variables, such as production quantity, price and supplied areas. Nowadays the supply base of rare metals is threatened by the sudden increase in price. For the stable supply of rare metals, a rational demand outlook is needed. In this study, focusing on the domestic demand for chromium, the uncertainty and probability materializing from demand and price is analyzed, further, a demand forecast model, which takes into account various exogenous variables, is suggested, differing from the previously static model. Also, through the OOS(out-of-sampling) method, comparing to the preexistence ARIMA model, ARMAX model, multiple regression analysis model and ECM(Error Correction Mode) model, we will verify the superiority of suggested model in this study.