An Approximation Algorithm for Solving a Class of Minimax Problem

Yingchun Zheng 보안공학연구지원센터 2016 International Journal of Grid and Distributed Comp Vol.9 No.5

Based on the the characteristics of maximal function, the algorithm for solving Min- max problem was researched in this paper. A new differential approximation function for the nondifferentiability of the objection function was also constructed. At same time, the property of the new differential approximation function is discussed and the processes of proves show that using the new approximation function to solve the nonlinear unconstrained min-max problem is feasible and effective. The preliminary numerical example shows that the algorithm is effective, and that have a large of convergence characteristics.

Sensory, Physicochemical, and Microbiological Changes in Vacuum Packed Channel Catfish (Clarias lazera) Patties during Controlled Freezing-point Storage

Yingchun Zhu,Kunsheng Zhang,Lizhen Ma,Nairui Huo,Hua Yang,Jiaomin Hao 한국식품과학회 2015 Food Science and Biotechnology Vol.24 No.4

Sensory, physicochemical, and microbiological changes of channel catfish patties stored under controlled freezing-point storage (CFPS) conditions at −1.5℃ for 10 weeks were analyzed to determine useful parameters for freshness evaluation and shelf-life determination. The sensory parameters of aerobic mesophilic and psychrophilic bacterial counts, physicochemical parameters of thiobarbituric acid, total volatile basic nitrogen, chewiness, ATP-ase activity, and the lightness parameter L* were correlated with storage time. Vacuum-packaged patties containing a cryoprotectant, natural antioxidants, and an antimicrobial mixture stored at −1.5℃ exhibited an extended shelf-life from a conventional 1-2 weeks to 6 weeks. Parameters that were correlated with storage time can be used as indicators of quality degradation of patties. CFPS combined with vacuum packaging offers an effective approach to extension of catfish product shelf-life.

Image saliency detection based on geodesic‐like and boundary contrast maps

Yingchun Guo,Yi Liu,Runxin Ma 한국전자통신연구원 2019 ETRI Journal Vol.41 No.6

Image saliency detection is the basis of perceptual image processing, which is significant to subsequent image processing methods. Most saliency detection methods can detect only a single object with a high‐contrast background, but they have no effect on the extraction of a salient object from images with complex low‐contrast backgrounds. With the prior knowledge, this paper proposes a method for detecting salient objects by combining the boundary contrast map and the geodesics‐like maps. This method can highlight the foreground uniformly and extract the salient objects efficiently in images with low‐contrast backgrounds. The classical receiver operating characteristics (ROC) curve, which compares the salient map with the ground truth map, does not reflect the human perception. An ROC curve with distance (distance receiver operating characteristic, DROC) is proposed in this paper, which takes the ROC curve closer to the human subjective perception. Experiments on three benchmark datasets and three low‐contrast image datasets, with four evaluation methods including DROC, show that on comparing the eight state‐of‐the‐art approaches, the proposed approach performs well.

Paired Hayman conjecture and uniqueness of complex delay-differential polynomials

Yingchun Gao,Kai Liu 대한수학회 2022 대한수학회보 Vol.59 No.1

In this paper, the paired Hayman conjecture of different types are considered, namely, the zeros distribution of $f(z)^{n}L(g)-a(z)$ and $g(z)^{n}L(f)-a(z)$, where $L(h)$ takes the derivatives $h^{(k)}(z)$ or the shift $h(z+c)$ or the difference $h(z+c)-h(z)$ or the delay-differential $h^{(k)}(z+c)$, where $k$ is a positive integer, $c$ is a non-zero constant and $a(z)$ is a non-zero small function with respect to $f(z)$ and $g(z)$. The related uniqueness problems of complex delay-differential polynomials are also considered.

Fuzzy Fractional Order Sliding Mode Control for Automatic Clutch of Vehicle AMT

Yingchun Long,Lifu Li 보안공학연구지원센터 2015 International Journal of Smart Home Vol.9 No.2

The automatic clutch driving system of vehicle automated manual transmission (AMT) is a typical nonlinear system. A fast and accurate position control is difficult to achieve because of the nonlinearity of the load changes caused by the clutch diaphragm spring, the cushion spring, and other nonlinear components and because of the uncertainty of the load changes caused by the cushion spring deformation in the clutch engagement process at varying temperatures on the friction surface. In this paper, based on the theory of fractional calculus and traditional sliding mode control, the method of fuzzy fractional order sliding mode control (FFOSMC) is proposed for clutch control. By selecting the fractional order sliding surface, the laws of control are designed; and self-tuning of the switch gain is realized with the fuzzy controller. Theoretical analysis and numerical simulation revealed that compared with the traditional fuzzy integer order sliding mode controller, FFOSMC achieves better dynamic performance in position control and better robustness against load disturbance and other uncertain factors.

Random sampling and reconstruction of signals with finite rate of innovation

Yingchun Jiang,Junjian Zhao 대한수학회 2022 대한수학회보 Vol.59 No.2

In this paper, we mainly study the random sampling and reconstruction of signals living in the subspace $V^p(\Phi,\Lambda)$ of $L^p(\mathbb{R}^d)$, which is generated by a family of molecules $\Phi$ located on a relatively separated subset $\Lambda\subset \mathbb{R}^d$. The space $V^p(\Phi,\Lambda)$ is used to model signals with finite rate of innovation, such as stream of pulses in GPS applications, cellular radio and ultra wide-band communication. The sampling set is independently and randomly drawn from a general probability distribution over $\mathbb{R}^d$. Under some proper conditions for the generators $\Phi=\{\phi_\lambda:\lambda\in \Lambda\}$ and the probability density function $\rho$, we first approximate $V^{p}(\Phi,\Lambda)$ by a finite dimensional subspace $V^{p}_N(\Phi,\Lambda)$ on any bounded domains. Then, we prove that the random sampling stability holds with high probability for all signals in $V^{p}(\Phi,\Lambda)$ whose energy concentrate on a cube when the sampling size is large enough. Finally, a reconstruction algorithm based on random samples is given for signals in $V^{p}_N(\Phi,\Lambda)$.

Compound Control of Sliding-Model Variable Structure and Fractional Order PIλDμ for Automatic Clutch of Vehicle AMT

Yingchun Long,Lifu Li 보안공학연구지원센터 2014 International Journal of Control and Automation Vol.7 No.5

Cloning, Expression, and Characterization of Polyamidase from Nocardia farcinica and Its Application to Polyamide Modification

Yingchun Guo,Sheng Chen,Lingqia Su,Jing Wu,Jian Chen 한국생물공학회 2013 Biotechnology and Bioprocess Engineering Vol.18 No.6

Polyamidase was able to hydrolyze the amidebond of insoluble polymer. In the present study, apolyamidase from Nocardia farcinica CGMCCC4.1166was cloned and expressed in E. coli BL21(DE3). Therecombinant polyamidase was purified to homogeneity,through a combination of chromatography of anion exchange,and hydrophobic interaction. The purified enzyme wascharacterized in detail. The optimum temperature of theenzyme was 50°C, and it was stable below 40°C. Theenzyme had an optimum pH of 8.0, with pH stabilitybetween pH 7.0 and 9.0. The enzyme does not need metalion as cofactor. In addition, when the enzyme was utilizedto hydrolyze polyamide, the monomeric product of adipicacid was verified by HPLC analysis; as well, the wettabilityand dyeability of polyamide fabric after enzyme treatmentwere significantly improved, which differed from those ofits inactive S173A mutant, and the amidase from Rhodococcuspyridinivorans. Furthermore, the structural featuresnear the active site of polyamidase, different from otheramidases, were explored.

Preparation of Nanophase Titania Film by Plasma Spraying

Zhu, Yingchun,Huang, Minhui The Korean Vacuum Society 1997 Applied Science and Convergence Technology Vol.6 No.1

Nanophase titania film was obtained by plasma spraying. The structure of titania film was investigated with transmission electron microscopy (TEM). It was found taht the film was composed of grains with mean particle size of 15nm. The crystal structure of nanophase titania film was found to be anatase phase by electron diffraction.

Incorporating additive manufacturing constraints into magneto-structural topology optimization

Bai Yingchun,Cai Jiale,Wang Zixiang,Li Siqi 한국CDE학회 2022 Journal of computational design and engineering Vol.9 No.5

The sequential using of topology optimization and AM (additive manufacturing) can generate and fabricate superior-performance yet lightweight magneto-structural components. In this paper, a magneto-structural topology optimization method is proposed considering AM constraints to improve the design manufacturability of optimized designs. The design problem is formulated with the weighted combination of magnetic compliance and mechanical compliance as a single objective subjected to two types of manufacturing constraints and the volume fraction constraint. Two important AM constraints are in a sequential manner incorporated into the topology optimization model, in which the overhang angle constraint is followed by the maximum length scale constraint. Corresponding sensitivities of the objective and constraints are derived, and the optimization problem is solved by the method of moving asymptotes. Two numerical examples and a practical conceptual design of linear motor rotor structure are systematically investigated to demonstrate the effectiveness of the proposed method.