• Safety and Health at Work
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• v.2 no.4
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• pp.321-327
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• 2011

Objectives: To find out from an analysis of empirical data the levels of influence, which a labor union (LU) and Occupational Safety and Health Committee (OSHC) have in reducing the occupational injury and illness rate (OIIR) through their accident prevention activities in manufacturing industries with five or more employees. Methods: The empirical data used in this study are the Occupational Safety and Health Tendency survey data, Occupational Accident Compensation data and labor productivity and sales data for the years 2003 to 2007. By matching these three sources of data, a final data set (n = 280) was developed and analyzed using SPSS version 18 (SPSS Inc., Chicago, IL, USA). Results: It was found that a workplace with a LU has a lower OIIR than one without a LU. In manufacturing industries with five or more employees in 2007, the OIIR of the workplaces without a LU was 0.87%, while that of workplaces with a LU was much lower at 0.45%. In addition, workplaces with an established OSHC had a lower OIIR than those without an OSHC. Conclusion: It was found that the OIIR of workplaces with a LU is lower than those without a LU. Moreover, those with the OSHC usually had a lower OIIR than those without. The workplace OIIR may have an impact on management performance because the rate is negatively correlated with labor productivity and sales. In the long run, the OIIR of workplaces will be reduced when workers and employers join forces and recognize that the safety and health activities of the workplace are necessary, not only for securing the health rights of the workers, but also for raising labor productivity.

• Korean Journal of Materials Research
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• v.29 no.9
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• pp.559-566
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• 2019

$Lu(Nb,Ta)O_4:Eu^{3+}$ powders are synthesized by a solid-state reaction process using LiCl and $Li_2SO_4$ fluxes. The photoluminescence (PL) excitation spectra of the synthesized powders consist of broad bands at approximately 270 nm and sharp peaks in the near ultraviolet region, which are assigned to the $Nb^{5+}-O^{2-}$ charge transfer of $[NbO_4]^{3-}$ niobates and the f-f transition of $Eu^{3+}$, respectively. The PL emission spectra exhibit red peaks assigned to the $^5D_0{\rightarrow}^7F_J$ transitions of $Eu^{3+}$. The strongest peak is obtained at 614 nm ($^5D_0{\rightarrow}^7F_2$), indicating that the $Eu^{3+}$ ions are incorporated into the $Lu^{3+}$ asymmetric sites. The addition of fluxes causes the increase in emission intensity, and $Li_2SO_4$ flux is more effective for enhancement in emission intensity than is LiCl flux. The substitution of $Ta^{5+}$ for $Nb^{5+}$ results in an increase or decrease in the emission intensity of $LuNb_{1-x}Ta_xO_4:Eu^{3+}$ powders, depending on amount and kind of flux. The findings are explained using particle morphology, modification of the $[NbO_4]^{3-}$ structure, formation of substructure of $LuTaO_4$, and change in the crystal field surrounding the $Eu^{3+}$ ions.

• International journal of advanced smart convergence
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• v.6 no.4
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• pp.73-79
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• 2017

The Convolutional Neural Network (CNN) has shown an excellent performance in computer vision task. Applications of CNN include image classification, object detection in images, autonomous driving, etc. This paper will evaluate the performance of CNN model with ReLU and SELU as activation function. The evaluation will be performed on four different choices of hyperparameter which are initialization method, network configuration, optimization technique, and regularization. We did experiment on each choice of hyperparameter and show how it influences the network convergence and test accuracy. In this experiment, we also discover performance improvement when using SELU as activation function over ReLU.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.21 no.8
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• pp.1311-1321
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• 1997

In multibody dynamics, differential and algebraic equations which can satisfy both equation of motion and kinematic constraint equation should be solved. To solve these equations, coordinate partitioning method and constraint stabilization method are commonly used. In the coordinate partitioning method, the coordinates are divided into independent and dependent and coordinates. The most typical coordinate partitioning method are LU decomposition, QR decomposition, and SVD (singular value decomposition). The objective of this research is to find an efficient coordinate partitioning method in the dynamic analysis of flexible multibody systems. Comparing two coordinate partitioning methods, i.e. LU and QR decomposition in the flexible multibody systems, a new hybrid coordinate partitioning method is suggested for the flexible multibody analysis.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.4
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• pp.848-855
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• 2011

This paper proposes a method to reduce the limit cycle phenomenon that appears in the steady-state response of a pendubot system, when it is controlled by a state feedback controller based on the linearized system model. For this, we employed the compensator which estimates the friction based on the LuGre model in the LQR control. The proposed compensation method is validated by experiments for a pendubot system, which shows that the external disturbance as well can be efficiently compensated.

• East Asian mathematical journal
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• v.39 no.5
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• pp.523-528
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• 2023

Let S_n = [S(i, j)]_1≤i,j≤n and S^*_n = [S(i + j, j)]_1≤i,j≤n where S(i, j) is the Stirling number of the second kind. Choi and Jo [On the determinants of the square-type Stirling matrix and Bell matrix, Int. J. Math. Math. Sci. 2021] obtained the diagonal entries of matrix U in the LU-factorization of S^*_n for calculating the determinant of S^*_n, where L = S_n. In this paper, we compute the all entries of U in the LU-factorization of matrix S^*_n. This implies the identities related to Stirling numbers of both kinds.

• Nuclear Engineering and Technology
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• v.55 no.1
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• pp.254-260
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• 2023

Skeletal metastases are common in patients suffering from various primary cancers. Radiopharmaceuticals are an effective option for bone pain palliation. In this work, the radiation absorbed dose of ¹⁷⁷Lu-EDTMP radiopharmaceutical was estimated for adult man based on biodistribution data in Wistar rats. The MIRD dose calculation method and the Sparks and Aydogan methodology were applied. The results shows that about 46% of injected activity is cumulated on the surface of the trabecular and cortical bones. Radiation absorbed doses of red bone marrow and osteogenic cells were estimated to about 1.1 and 6.2 mGy/MBq, respectively. The maximum administrated activity was obtained 27 MBq/kg of body weight with an effective dose of 0.23 mSv/MBq. The results were compared with other available data from literature. This study indicated that ¹⁷⁷Lu-EDTMP provides therapeutic efficacy for achieving bone pain palliation with low undesired dose to other normal organs.

• The Journal of Engineering Geology
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• v.34 no.2
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• pp.279-294
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• 2024

Large-scale civil engineering structures such as dams require a systematic approach to jointed rock-mass grouting to prevent water leakage into the foundations and to ensure safe operation. In South Korea, rock grouting design often relies on the experience of field engineers that was gained in similar projects, highlighting the need for a more systematic and reliable approach. Rock-mass grouting is affected mainly by hydrogeology and the presence of discontinuities, involving factors such as the rock quality designation (RQD), joint spacing (Js), Lugeon value (Lu), and secondary permeability index (SPI). This study, based on data from field investigations of 14 domestic sites, analyzed the correlation between hydrogeological factors (Lu and SPI), discontinuity characteristics (RQD and Js), and grout take, and systematically established a design method for rock grouting. Analysis of correlation between the variables RQD, Js, Lu, and SPI yielded Pearson correlation (r) values as follows: Lu-SPI, 0.92; RQD-Lu, -0.75; RQD-Js, 0.69; RQD-SPI, -0.65; Js-Lu, -0.47; and SPI-Js, -0.41. The grout take increases with Lu and SPI values, but there is no significant correlation between RQD and Js. The proposed approach for grouting design based on SPI values was verified through analysis and comparison with actual curtain-grouting construction, and is expected to be useful in practical applications and future studies.

• Korean Journal of Materials Research
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• v.26 no.4
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• pp.212-215
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• 2016

In this paper, cerium doped lutetium pyrosilicate (LPS) powders with cerium content (0.05 and 0.07 mol%) were prepared by sol-gel process. The formation of lutetium pyrosilicate (LPS) phase was confirmed by XRD analysis for the powders heated at $1,200^{\circ}C$; in these powders, a single phase of $Lu_2Si_2O_7$ (LPS) was observed. Cerium doped lutetium pyrosilicate (LPS) powder was agglomerated and constituted of small spherical particles with diameters of about 300 nm. The photoluminescence spectra of the $Lu_2Si_2O_7:Ce^{3+}$ powders showed the characteristic of excitation and there was an emission spectrum for $Ce^{3+}$ in the host of $Lu_2Si_2O_7$. The emission spectrum shows a broad band in the range of 350-525 nm; the broad wavelength on the right side of the spectra should be ascribed to the same 5d-4f transitions of $Ce^{3+}$, as in the case of cerium doped $Lu_2Si_2O_7$ single crystals.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.21
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• pp.9113-9116
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• 2014

Purpose: : To assess the clinic value of application of laparospic ultrasonography (LU) in partial nephrectomy of small renal cell carcinoma. Materials and Methods: From 2007 to 2011, 28 small renal cell carcinoma patients in ou clinic underwent laparoscopic partial nephrectomy with LU. For comparison with preoperative conventional ultrasound and CT, we collected ultrasonic performance of the affected side kidney, renal tumor location, size, echo change, blood supply situation and the relationship with the surrounding tissue. Results: LU could more clearly show the tumor interior structure and blood supply, as well as the relationship with the surrounding tissue. It also can provided doctor assistance with real-time tumor resection, reducing operative complications. Conclusions: LU can clearly show tumor internal structure and blood supply, which is helpful for explicit diagnosis. Moreover, it supplies accurate information for surgeons and assists surgery. Therefore LU has an important guiding value in partial nephrectomy for small renal cell carcinoma.