• Journal of Electrical Engineering and Technology
• /
• v.7 no.1
• /
• pp.132-140
• /
• 2012

A non-conservative robust Kalman filter (NCRKF) is applied to flight data to identify the aerodynamic derivatives of an unmanned autonomous vehicle (UAV). The NCRKF is formulated using UAV lateral motion data and then compared with results from the conventional Kalman filter (KF) and the recursive least square (RLS) method. A superior performance for the NCRKF is demonstrated by simulation and real flight data. The NCRKF is especially effective in large uncertainties in vehicle modeling and in measuring flight data. Thus, it is expected to be useful in missile and aircraft parameter identification.

• The Transactions of the Korean Institute of Electrical Engineers D
• /
• v.53 no.3
• /
• pp.145-153
• /
• 2004

A nonlinear adaptive speed observer is designed for the sensorless control of induction motors. In order to design the speed observer, the measurements of the stator currents and the estimates of the rotor fluxes are used. The sliding mode cascade observer is designed to estimate the time derivatives of the stator currents. The open-loop observer is designed to estimate the rotor fluxes and its time derivatives using the stator current derivatives. The adaptive observer is also designed to estimate the rotor resistance. Sequentially, the rotor speed is calculated using these estimated values. It is shown that the estimation errors of the corresponding states and the parameters converge to the specified residual set. It is also shown that the speed controller using these estimates is performed well. The simulation examples are represented to investigate the validity of the proposed observers for the sensorless control of induction motors.

• The Plant Pathology Journal
• /
• v.34 no.1
• /
• pp.44-58
• /
• 2018

Pseudomonas chlororaphis 30-84 is a biological control agent selected for its ability to suppress diseases caused by fungal pathogens. P. chlororaphis 30-84 produces three phenazines: phenazine-1-carboxylic acid (PCA), 2-hydroxy-phenazine-1-carboxylic acid (2OHPCA) and a small amount of 2-hydroxy-phenazine (2OHPHZ), and these are required for fungal pathogen inhibition and wheat rhizosphere competence. The two, 2-hydroxy derivatives are produced from PCA via the activity of a phenazine-modifying enzyme encoded by phzO. In addition to the seven biosynthetic genes responsible for the production of PCA, many other Pseudomonas strains possess one or more modifying genes, which encode enzymes that act independently or together to convert PCA into other phenazine derivatives. In order to understand the fitness effects of producing different phenazines, we constructed isogenic derivatives of P. chlororaphis 30-84 that differed only in the type of phenazines produced. Altering the type of phenazines produced by P. chlororaphis 30-84 enhanced the spectrum of fungal pathogens inhibited and altered the degree of take-all disease suppression. These strains also differed in their ability to promote extracellular DNA release, which may contribute to the observed differences in the amount of biofilm produced. All derivatives were equally important for survival over repeated plant/harvest cycles, indicating that the type of phenazines produced is less important for persistence in the wheat rhizosphere than whether or not cells produce phenazines. These findings provide a better understanding of the effects of different phenazines on functions important for biological control activity with implications for applications that rely on introduced or native phenazine producing populations.

• International Journal of Aeronautical and Space Sciences
• /
• v.18 no.2
• /
• pp.175-185
• /
• 2017

This paper presents new differential methods for computing the combined and single dynamic stability derivatives of flight vehicle. Based on rigid dynamic mesh technique, the combined dynamic stability derivative can be achieved by imposing the aircraft pitching to the same angle of attack with two different pitching angular velocities and also translating it to the same additional angle of attack with two different rates of angle of attack. As a result, the acceleration derivative is identified. Moreover, the rotating reference frame is adopted to calculate the rotary derivatives when simulating the steady pull-up with different pitching angular velocities. Two configurations, the Hyper Ballistic Shape (HBS) and Finner missile model, are considered as evaluations and results of all the cases agree well with reference or experiment data. Compared to traditional ones, the new differential methods are of high efficiency and accuracy, and potential to be extended to the simulation of combined and single stability derivatives of directional and lateral.

• 제어로봇시스템학회:학술대회논문집
• /
• 1992.10b
• /
• pp.526-531
• /
• 1992

Partial derivatives are easily computed analytically assuming that all the geometric information is known. However, there are computational difficulties in getting accurate partial derivatives directly from a range image since an image is a discrete version of continuous data contaminated with some noise. In this paper, we develop a general window function to compute partial derivatives based on the least square surface fitting method. A dynamic selective surface fitting method is introduced to make the window less sensitive to noise. Any degree of partial derivative can be obtained by a simple convolution between an image and window functions.

• Journal of the Korean Chemical Society
• /
• v.38 no.8
• /
• pp.603-607
• /
• 1994

New cephalosporin antibiotics,7-[(3,4-dihydro-6-methoxycarbonyl-2,2-dimethyl-2H-1,4-thiazin-3-yl)acetamido]-3-[(substituted pyrimidin-2-yl)thiomethyl]-3-cephem-4-carboxylic acid derivatives(2a∼2d) were synthesized. These new cephalosporin derivatives were prepared by the introduction of pyridinylthiomethyl moiety in 3-position and thiazine group in 7-position of 7-ACA. Antibacterial activities of these compounds were examined and the relationship between structure and activities were studied. As the result, these compounds showed low antibacterial activities compared to cefotaxim used as control.

• YAKHAK HOEJI
• /
• v.36 no.2
• /
• pp.110-114
• /
• 1992

In order to evaluate the antimicrobial effect of 2, 3-substituted-1, 4-naphthoquinone derivatives, we newly synthesized several 2-chloro, 2-bromo and 2-hydroxy-1, 4-naphthoquinones and subjected to antibacterial and antifungal activities, in vitro, against Escherichia coli NIHJ, Staphylococcus aureus ATCC6538p, Candida albicans 10231, Aspergillus niger 1231 and Tricophyton mentagrophytes 6085. Among these derivatives 3, 9, 18 and 23 showed the potent antibacterial activities. 18, 23 and 28 have the antifungal activities. However, these compounds have no significant hemolytic activity at concentrations higher than that required for showing the antibacterial and antifungal activities.

• Bulletin of the Korean Chemical Society
• /
• v.13 no.4
• /
• pp.407-413
• /
• 1992

The chromatographic separation of the stereoisomers of the N-(3,5-dinitrobenzoyl) derivatives of fifteen dipeptide methyl esters and nine dipeptide alkyl esters was investigated on three different chiral stationary phases derived from N-acylated ${\alpha}-arylalkylamines$. Two of these CSPs contain second stereogenic centers. These secondary stereogenic centers of CSPs were proposed to provide secondary effects in terms of chiral recognition. From the elution orders of the four dipeptide stereoisomers and the separation factors of the enantiomeric pairs of the N-(3,5-dinitrobenzoyl) derivatives of the dipeptide alkyl esters having different alkoxy substituents, it was proposed that the intercalation of the alkoxy substituents of dipeptide derivatives between the connecting arm of CSPs may control the magnitude of chiral separations of dipeptide derivatives.

• Steel and Composite Structures
• /
• v.48 no.6
• /
• pp.611-623
• /
• 2023

This work considered an optimal control formulation in the sense of Caputo derivatives. The optimality of the fractional optimal control problem. The tumor immune interaction in fractional form provides an excellent tool for the description of memory and hereditary properties of inter and intra cells. So the interaction between effector-cells, tumor cells and are modeled by using the definition of Caputo fractional order derivative that provides the system with long-time memory and gives extra degree of freedom. In addiltion, existence and local stability of fixed points are investigated for discrete model. Moreover, in order to achieve more efficient computational results of fractional-order system, a discretization process is performed to obtain its discrete counterpart. Our technique likewise allows the advancement of results, such as return time to baseline that are unrealistic with current model solvers.

• BMB Reports
• /
• v.38 no.4
• /
• pp.474-480
• /
• 2005

Curcumin, a major active component of turmeric, has been identified as an inhibitor of the transcriptional activity of activator protein-1 (AP-1). Recently, it was also found that curcumin and synthetic curcumin derivatives can inhibit the binding of Jun-Fos, which are the members of the AP-1 family, to DNA. However, the mechanism of this inhibition by curcumin and its derivatives was not disclosed. Since the binding of Jun-Fos dimer to DNA can be modulated by redox control involving conserved cysteine residues, we studied whether curcumin and its derivatives inhibit Jun-Fos DNA binding activity via these residues. However, the inhibitory mechanism of curcumin and its derivatives, unlike that of other Jun-Fos inhibitors, was found to be independent of these conserved cysteine residues. In addition, we investigated whether curcumin derivatives can inhibit AP-1 transcriptional activity in vivo using a luciferase assay. We found that, among the curcumin derivatives examined, only inhibitors shown to inhibit the binding of Jun-Fos to DNA by Electrophoretic Mobility Shift Assay (EMSA) inhibited AP-1 transcriptional activity in vivo. Moreover, RT-PCR revealed that curcumin derivatives, like curcumin, downregulated c-jun mRNA in JB6 cells. These results suggest that the suppression of the formation of DNA-Jun-Fos complex is the main cause of reduced AP-1 transcriptional activity by curcuminoids, and that EMSA is a suitable tool for identifying inhibitors of transcriptional activation.