• Bulletin of the Korean Mathematical Society
• /
• v.26 no.1
• /
• pp.35-42
• /
• 1989

Let .ohm.$_{n}$ and Pm $t_{n}$ denote the sets of all n*n doubly stochastic matrices and the set of all n*n permutation matrices respectively. For m*n matrices A=[ $a_{ij}$ ], B=[ $b_{ij}$ ] we write A.leq.B(A$a_{ij}$ .leq. $b_{ij}$ ( $a_{ij}$ < $b_{ij}$ ) for all i=1,..,m; j=1,..,n. Let $I_{n}$ denote the identity matrix of order n, let $J_{n}$ denote the n*n matrix all of whose entries are 1/n, and let $K_{n}$=n $J_{n}$. For a complex square matrix A, the permanent of A is denoted by per A. Let $E_{ij}$ denote the matrix of suitable size all of whose entries are zeros except for the (i,j)-entry which is one.hich is one.

• Smart Structures and Systems
• /
• v.29 no.6
• /
• pp.799-805
• /
• 2022

Permanent magnet synchronous motors (PMSMs) are widely used in systems requiring high control precision, efficiency, and reliability. Predicting the remaining useful life (RUL) with health monitoring of PMSMs prevents catastrophic failure and ensures reliable operation of system. In this study, a model-based method for predicting the RUL of PMSMs using phase current and vibration signals is proposed. The proposed method includes feature selection and RUL prediction based on a particle filter with a degradation model. The Paris-Erdogan model describing micro fatigue crack propagation is used as the degradation model. An experimental set-up to conduct accelerated life test, capable of monitoring various signals was designed in this study. Phase current and vibration data obtained from an accelerated life test of the PMSMs were used to verify the proposed approach. Features extracted from the data were clustered based on monotonicity and correlation clustering, respectively. The results identify the effectiveness of using the current data in predicting the RUL of PMSMs.

• Nuclear Engineering and Technology
• /
• v.56 no.7
• /
• pp.2704-2710
• /
• 2024

Nuclear archaeology research provides scientific methods to reconstruct the operating histories of fissile material production facilities to account for past fissile material production. While it has typically focused on analyzing material in permanent reactor structures, spent fuel or high-level waste also hold information about the reactor operation. In this computational study, we explore a Bayesian inference framework for reconstructing the operational history from measurements of isotope ratios from a sample of nuclear waste. We investigate two different inference models. The first model discriminates between three potential reactors of origin (Magnox, PWR, and PHWR) while simultaneously reconstructing the fuel burnup, time since irradiation, initial enrichment, and average power density. The second model reconstructs the fuel burnup and time since irradiation of two batches of waste in a mixed sample. Each of the models is applied to a set of simulated test data, and the performance is evaluated by comparing the highest posterior density regions to the corresponding parameter values of the test dataset. Both models perform well on the simulated test cases, which highlights the potential of the Bayesian inference framework and opens up avenues for further investigation.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2004.11a
• /
• pp.311-316
• /
• 2004

LMTT (Linear Motor-based Transfer Technology) is a horizontal transfer system for the yard automation. which has been proposed to take the place qf AGV (Automated Guided Vehicle) in the maritime container terminal. the system is based on PMLSM (Permanent Magnetic Linear Synchronous Motor) that consists of stator modules on the rail and shuttle mr. It is desirable to reduce the weight of LMTT in order to control the electronic devices with minimum energy. In this research structural optimization for a mover of shuttle mr is performed to minimize the weight satisfying design criteria the objective function is set up as weight. On the contrary, design variable is considered as transverse, longitudinal and wheel beam's thickness and shape variable determining the dimension toward high direction and the constraints are the stresses.

• Journal of Industrial Technology
• /
• v.36
• /
• pp.71-76
• /
• 2016

In this study, we determined the precise coordinates of TBMs (Tidal Bench Marks), which used as the national reference points in coastal area of Korea, using a GPS data analysis SW for the academic and scientific applications, GAMIT/GLOBK. For accurate 3-D positioning of TBM locations, we performed the GPS point surveying according to the national surveying policy and also acquired the GPS data for 48 TBMs located in the western and southern coastal part of Korea. Considering the results of baseline analysis to each observation session obtained from GAMIT module, the baseline analysis was realized to be done precisely because the values of Normalized RMS (NRMS) were mostly less than ${\pm}0.20mm$. Before the network adjustment using GLOBK module, we evaluated the suitability of observations for each session by applying the chi-squared test (${\chi}^2$ test) to the degree of freedom in observed session. An overall distributions of ${\chi}^2$ test were less than 1.0 for all sessions, and the statistical of ${\chi}^2$ test showed the average, 0.267 with minimum and maximum value, 0.063 and 0.653, respectively. Finally, we analyzed the network adjustment for 48 TBMs to reduce the residuals of baseline analysis on each point by connecting with 42 permanent GPS stations in Korea. In the network adjustment procedure, we set up the weighted values of each permanent station to be allocated between 0.9 and 1.14, and also removed the observed points having residual exceeds 4-times of standard deviation ($4{\sigma}$).

• Journal of Korean Society of Water and Wastewater
• /
• v.26 no.3
• /
• pp.431-442
• /
• 2012

The purpose of this study, is to separate magnetic separation devices using permanent magnets by using magnetization characteristics remaining in treated water after adsorption and synthesizing phosphorus adsorbent capable of magnetic separation for efficient removal of phosphorus. The synthesis of the adsorbent which set Zirconium(Zr) having high friendly features for phosphorus as an element, and by synthesizing Iron Oxide($Fe_3O_4$, another name of $Fe_3O_4$ is magnetite) being able to grant magnetism to Zirconium Sulfate($Zr(SO_4)_2$), zirconium magnetic adsorbent(ZM) were manufactured. In order to consider the phosphorus adsorption characteristics of adsorbent ZM, batch adsorption experiment was performed, and based on the results, pH effect, adsorption isotherm, adsorption kinetics, and magnetic separation have been explore. As the experiment result, adsorbent ZM showed a tendency that the adsorption number was decreased rapidly at pH 13; however, it was showed a high amount of phosphorus removal in other range and it showed the highest amount of phosphorus removal in pH 6 of neutral range. In addtion, the Langmuir adsorption isotherm model is matched well, and D-R adsorption isotherm model is ranged 14.43kJ/mol indicating ion exchange mechanism. The result shown adsorption kinetics match well to the Pseudo-second-order kinetic model. The adsorbent ZM's capablility of regenerating NaOH and $H_2SO_4$, was high selectivity on the phosphorus without impacts on the other anions. The results of applying the treated water after adsorption of phosphorus to the magnetic separation device by using permanent magnets, shows that capture of the adsorbent by the magnetization filter was perfect. And they show the possibility of utilization on the phosphorus removal in water.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• v.29 no.1
• /
• pp.385-390
• /
• 2005

LMTT (Linear Motor-based Transfer Techn-ology) is a horizontal transfer system for the yard automation, which has been proposed to take the place of AGV (Automated Guided Vehicle) in the maritime container terminal. The system is based on PLMSL (Permanent Magnetic Linear Synchronous Motor) that consists of stator modules on the rail and shuttle car. It is desirable to reduce the weight of LMTT in order to control the electronic devices with minimum energy. In this research, the DACE modeling, known as the one of Kriging interpolation, is introduced to obtain the surrogate approximation model of the structural responses. Then, the GRG(Generalized Reduced Gradient) method built in Excel is adopted to determine the optimum. The objective function is set up as weight. On the contrary, the design variables are considered as transverse, longitudinal and wheel beam's thicknesses, and the constraints are the maximum stresses generated by four loading conditions.

• Journal of Advanced Navigation Technology
• /
• v.14 no.2
• /
• pp.233-238
• /
• 2010

In this paper, we applied the forward and backward error recovery techniques to a reduced instruction set computer (risc) processor to develop two fault-tolerant processors, namely, fetch redundant risc (FRR) processor and a redundancy execute risc (RER) processor. To evaluate the fault-tolerance capability of three target processors, we developed the base risc processor, FRR processor, and RER processor in SystemC hardware description language. We performed fault injection experiment using the three SystemC processor models and the SystemC-based simulation fault injection technique. From the experiments, for the 1-bit transient fault, the failure rate of the FRR, RER, and base risc processor were 1%, 2.8%, and 8.9%, respectively. For the 1-bit permanent fault, the failure rate of the FRR, RER, and base risc processor were 4.3%, 6.5%, and 41%, respectively. As a result, for 1-bit fault, we found that the FRR processor is more reliable among three processors.

• Journal of the Korean Society of Clothing and Textiles
• /
• v.33 no.3
• /
• pp.391-400
• /
• 2009

The purpose of this study is to investigate the efficacy of safflower yellow colorant as a natural dye for hair coloring. The dyeing properties of safflower yellow colorant on hair were explored to obtain optimum conditions. Also, the effect of mordant was studied in terms of dye uptake, colorfastness, and hair damage to better understand the characteristics of the colorant. Tensile strength measurement and SEM analysis were carried out for investigating hair damage to light exposure and washing. On the basis of obtained results considering possible hair damage, optimum dyeing conditions were set 100%(o.w.h.) colorant concentration, pH 5, $40^{\circ}C$, and 20min. Dye uptake was improved more effectively by repeated dyeing rather than by increasing concentration. Pre-mordanting method improved dye uptake slightly, irrespective of mordant type. The safflower yellow colorant produced Y colors on hair. Cu and Fe mordants improved washing and light fastness slightly. Better strength retention was obtained with the mordanted-dyed hair than the unmordanted-dyed hair after light irradiation for 40 hours and 10 repeated washing. The hair was more damaged by light exposure than by washing. It was concluded that the safflower yellow colorant can be used as a natural semi-permanent hair dye producing Y color without mordanting.

• Journal of Electrical Engineering and Technology
• /
• v.13 no.5
• /
• pp.1945-1955
• /
• 2018

High frequency signal injection (HFI) is an alternative method for estimating rotor position of interior permanent magnet synchronous motor (IPMSM). The general method of frequency and amplitude selection is based on error tolerance and experiments, and is usually set with only one group of HF parameters, which is not efficient for different working modes. This paper proposes a novel rotor position estimation scheme by HFI with optimized frequency and amplitude, based on the mathematic model of IPMSM. The requirements for standstill and low-speed operational modes are met by applying this novel scheme. Additionally, the effects of the frequency and amplitude of the injected HF signal on the position estimation results under different operating conditions are analyzed. Furthermore, an optimization method for HF parameter selection is proposed to make the estimation process more efficient under different working conditions according to error tolerance. The effectiveness of the propose scheme is verified by the experiments on an IPMSM motor prototype.