• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.10 no.10
• /
• pp.5095-5111
• /
• 2016

The Probability Hypothesis Density (PHD) filter is a suboptimal approximation and tractable alternative to the multi-target Bayesian filter based on random finite sets. However, the PHD filter fails to track newborn targets when the target birth intensity is unknown prior to tracking. In this paper, a dual detection-guided newborn target intensity PHD algorithm is developed to solve the problem, where two schemes, namely, a newborn target intensity estimation scheme and improved measurement-driven scheme, are proposed. First, the newborn target intensity estimation scheme, consisting of the Dirichlet distribution with the negative exponent parameter and target velocity feature, is used to recursively estimate the target birth intensity. Then, an improved measurement-driven scheme is introduced to reduce the errors of the estimated number of targets and computational load. Simulation results demonstrate that the proposed algorithm can achieve good performance in terms of target states, target number and computational load when the newborn target intensity is not predefined in multi-target tracking systems.

• Communications of the Korean Mathematical Society
• /
• v.24 no.4
• /
• pp.481-500
• /
• 2009

The concepts of *-relation of a ($\Gamma$-)semigroup and $\bar{\Gamma}$-adequate transversal of a ($\Gamma$-)abundant semigroup are defined in this note. Then we develop a matrix type theory for abundant semigroups. We give some equivalent conditions of a Rees matrix semigroup being abundant and some equivalent conditions of an abundant Rees matrix semigroup having an adequate transversal. Then we obtain some Rees matrix representations for abundant semigroups with adequate transversals by the above theories.

• Journal of Power Electronics
• /
• v.17 no.4
• /
• pp.1071-1087
• /
• 2017

This paper introduces a DC/AC converter, which can be connected in parallel with a diode rectifier for regenerative applications. The DC/AC converter is supposed to transmit regenerative energy to the power grid when a motor is braking. Isolation transformers are not needed in the topology, which can reduce the size and cost. An analysis of the zero-order current existing in the system is carried out. In addition, algorithms to minimize the zero-order current, control the power factor and keep the DC bus voltage stable are discussed. A 55kW industrial prototype is built to verify the proposed analysis and control strategies.

• Steel and Composite Structures
• /
• v.33 no.2
• /
• pp.163-180
• /
• 2019

A semi analytical method is employed to analyze free vibration characteristics of uniform and stepped functionally graded circular cylindrical shells under complex boundary conditions. The analytical model is established based on multi-segment partitioning strategy and first-order shear deformation theory. The displacement functions are handled by unified Jacobi polynomials and Fourier series. In order to obtain continuous conditions and satisfy complex boundary conditions, the penalty method about spring technique is adopted. The solutions about free vibration behavior of functionally graded circular cylindrical shells were obtained by approach of Rayleigh-Ritz. To confirm the dependability and validity of present approach, numerical verifications and convergence studies are conducted on functionally graded cylindrical shells under various influencing factors such as boundaries, spring parameters et al. The present method apparently has rapid convergence ability and excellent stability, and the results of the paper are closely agreed with those obtained by FEM and published literatures.

• Nuclear Engineering and Technology
• /
• v.51 no.7
• /
• pp.1822-1827
• /
• 2019

Mechanical responses and failure behaviors of advanced C/C composite tube are very important for structural component design in nuclear reactor. In this study, an experimental investigation was conducted to study mechanical properties of C/C composite tube. Quasi-static compression loading was applied to a type of advanced composite tube to determine the response of the quasi-static load displacement curve during progressive damage. Acoustic emissions (AE) signals were captured and analyzed to characterize the crack formation and crack development. In addition, the crack propagation of the specimens was monitored by imaging technique and failure mode of the specimen was analyzed. FEM is appled to simulate the stress distribution. Results show that advanced C/C composite tube exhibits considerable energy absorption capability and stability in load-carrying capacity.

• Journal of Power Electronics
• /
• v.19 no.2
• /
• pp.463-474
• /
• 2019

This paper presents the effect of winding configuration on the kVA rating of a wye-connected autotransformer applied to a 12-pulse rectifier. To describe the winding configuration of the wye-connected autotransformer, position and proportional parameters are defined and their quantitative relation is calculated. The voltages across and currents through the windings are measured under different winding connections. Consequently, a relation between the kVA rating and position parameter is established in accordance with the analysis, and the optimal winding configuration is obtained on the basis of this relation. A wye-connected autotransformer with the least equivalent kVA rating and simplest winding configuration is designed and applied to the 12-pulse rectifier. Simulations and experiments are conducted to validate the theoretical analysis.

• Proceedings of the PSK Conference
• /
• 2002.10a
• /
• pp.379.1-379.1
• /
• 2002

As described previously. we reported twenty two compounds including one naphthoquinone. eight diarylheptanoids, two tetralone. one sesquiterpenoid. one diarylheptanoid glucoside, two tetralone glucosides. one naphthalene carboxylic acid glucoside and six naphthalenyl glycosides were isolated from the roots of Juglans mandshurica (17-22). Here we report that al of these compounds and a known triterpene are tested for the inhibitory effects against DNA topoisomerases I and II activities. (omitted)

• Proceedings of the PSK Conference
• /
• 2003.04a
• /
• pp.257.1-257.1
• /
• 2003

The bioassay-guided fractionation of preventive agents against lethality due to septic shock from the fruits of Illicium verum lead to the isolation of two known racemic mixtures of phenylpropanoids (1 and 2), along with two known phenylpropanoid glucosides (3 and 5) and two new phenylpropanoid glucosides (4 and 6). Their chemical structures were elucidated on the basis of spectroscopic studies. (omitted)

• Proceedings of the PSK Conference
• /
• 2003.10b
• /
• pp.199.2-199.2
• /
• 2003

The bioassay-guided fractionation of protective agents against sepsis-induced lethality from the root bark of Paeonia suffruticosa led to the isolation of ten known compounds: paeonol (1), 2,5-dihydroxy-4-methoxyacetophenone (2) methyl 3-hydroxy-4- methoxybenzoate (3), acetovanillone (4), benzoic acid (5), benzoylpaeoniflorin (6), paeonoside (7), paeoniflorin (8), oxypaeoniflorin (9) and apiopaeonoside (10). Among them, 4 exhibited the highest survival rate in a dose-dependent manner (100% with a dose of 30 mg/kg versus 16.7% for the control experiment) and showed reduction of plasma alanine aminotransferase (ALT) value on the in vivo assay model of sepsis induced by LPS/GalN.

• Proceedings of the PSK Conference
• /
• 2003.10b
• /
• pp.206.3-207
• /
• 2003

The bioassay-guided fractionation of the methylene chloride soluble portion of a methanol extract of Gastrodia elata tubers led to the isolation of a new furfural, 5-(4-hydroxy-benzyloxymethyl)-furan-2-carbaldehyde (2), together with four known compounds (1, 3-5), which exhibited potent inhibitory activity at the concentration of 25 $\mu\textrm{g}$/ml on melanin biosynthesis in cultured B-16 mouse melanoma cells.