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      • Study on Ddynamic Bargaining System Based on Machine Learning

        Haifeng Guo,Rongyi Cui 한국어정보학회 2006 한국어정보학 Vol.8 No.2

        In this paper, aiming at the learning deficiency in the given bargaining systems, the decimal code, instead of binary code, is adopted to prevent variables from going beyond limitative scope, which will cause exceptional strategy. Furthermore, a dynamic bargaining system is presented based on machine learning (MLDBS). The result of experiment shows that the agent in MLDBS not can only identify its opponents successfully but can change its strategy in term of different opponents in a bargaining process. It is shown by the experimental datum that MLDBS increase successful times of bargaining and enhance the average payoff of agent.

      • KCI등재

        Computational Fluid Dynamics Modeling of an Inverted Frustoconical Shaking Bioreactor for Mammalian Cell Suspension Culture

        Haifeng Hang,Yuanxin Guo,Jian Liu,Li Bai,Jianye Xia,Meijin Guo,Matthew Hui 한국생물공학회 2011 Biotechnology and Bioprocess Engineering Vol.16 No.3

        We previously developed an inverted frustoconical shaking bioreactor (IFSB) which had high mammalian cell culture performance when compared with a mechanically stirred tank reactor (STR) or a flat-bottom shaking bioreactor (FBSB). Here, we determined the mixing time (t) and volumetric oxygen transfer coefficient (kLa) of this IFSB at various speeds, and simulated the fluid hydrodynamics, including the shear stress and specific surface area, by computational fluid dynamics. The shortest mixing time was observed in a STR. The maximum kLa value of 12/h was achieved in the IFSB at an aeration rate of 4 L/h, demonstrating that our IFSB has enhanced oxygen transfer capabilities needed to meet the demands of mammalian cells. Simulation studies revealed a 3% greater specific surface area and a 21% lower shear strain in the IFSB compared to an FBSB under the same conditions. Additionally, the conical angle of the vessel, which significantly affected cell growth and recombinant protein production,was tested here. We conclude that, compared to the STR and FBSB, the IFSB has an increased liquid surface area for oxygen uptake and exhaust CO_2 stripping,an enhanced k_La for cell robust growth to a high cell density, and a lower shear stress to alleviate cell damage.

      • KCI등재

        Texture superpixels merging by color-texture histograms for color image segmentation

        ( Haifeng Sima ),( Ping Guo ) 한국인터넷정보학회 2014 KSII Transactions on Internet and Information Syst Vol.8 No.7

        Pre-segmented pixels can reduce the difficulty of segmentation and promote the segmentation performance. This paper proposes a novel segmentation method based on merging texture superpixels by computing inner similarity. Firstly, we design a set of Gabor filters to compute the amplitude responses of original image and compute the texture map by a salience model. Secondly, we employ the simple clustering to extract superpixles by affinity of color, coordinates and texture map. Then, we design a normalized histograms descriptor for superpixels integrated color and texture information of inner pixels. To obtain the final segmentation result, all adjacent superpixels are merged by the homogeneity comparison of normalized color-texture features until the stop criteria is satisfied. The experiments are conducted on natural scene images and synthesis texture images demonstrate that the proposed segmentation algorithm can achieve ideal segmentation on complex texture regions.

      • Application of Evaporative Cooling Technology in HDVC Converter Station

        Guo, Jianhong,Wang, Haifeng,Ai, Chengliu,Gu, Guobiao Journal of International Conference on Electrical 2014 Journal of international Conference on Electrical Vol.3 No.1

        Converter valve cooling device as the heat exchanger, is known as the converter valve's blood circulation system, Inefficiency of the equipment will not only lead to the component overheating damage, but also serious DC system outage. Therefore, reliable HVDC valve cooling system is essential for the HVDC transmission system. In this article, analysis on the two-phase flow heat transfer characteristics and security of the evaporative cooling technology are provided, the technology's advantage and feasibility are discussed.

      • KCI등재

        Epitaxial Growth of Strain-Induced Ferromagnetic LaCoO3 Thin Films by Simple Sol–Gel Technique

        Haifeng Liu,Yuqiao Guo,Ruishi Xie,Guohua Ma 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2016 NANO Vol.11 No.3

        LaCoO3 (LCO) epitaxial films were grown on (001) LaAlO3 (LAO) substrates by the simple sol– gel technique. X-ray diffraction (XRD) and the cross-section transmission electron microscope (TEM) measurements indicate that single-phase (001) oriented LCO epitaxial films with biaxial compressive strain and elongated distortion of CoO6 octahedrons were grown on (001) LAO successfully. The epitaxial relationship between the LCO film and the LAO substrate is confirmed to be (001)LCO||(001)LAO and [100]LCO||[100]LAO. It is also found that LCO grown on LAO has a larger mean Co–O bond length and unit-cell size, compared with those of polycrystalline film. In addition, the magnetic characterization shows that LCO epitaxial film exhibits an obvious ferromagnetic (FM) transition at TC ~ 85 K, which is different from the nonmagnetic ground state of polycrystalline LCO. Combined with the structural analyses, it reveals that the strain-induced ferromagnetism observed in LCO epitaxial film originates from an increase of the mean Co–O bond length and a suppression of the CoO6 octahedral rotations, which can stabilize higher spin state of Co3+ by a decrease of the eg~t2g gap energy.

      • SCIESCOPUSKCI등재

        ON π-EMBEDDED SUBGROUPS OF FINITE GROUPS

        Guo, Wenbin,Yu, Haifeng,Zhang, Li Korean Mathematical Society 2016 대한수학회보 Vol.53 No.1

        A chief factor H/K of G is called F-central in G provided $(H/K){\rtimes}(G/C_G(H/K)){\in}{\mathfrak{F}}$. A normal subgroup N of G is said to be ${\pi}{\mathfrak{F}}$-hypercentral in G if either N = 1 or $N{\neq}1$ and every chief factor of G below N of order divisible by at least one prime in ${\pi}$ is $\mathfrak{F}$-central in G. The symbol $Z_{{\pi}{\mathfrak{F}}}(G)$ denotes the ${\pi}{\mathfrak{F}}$-hypercentre of G, that is, the product of all the normal ${\pi}{\mathfrak{F}}$-hypercentral subgroups of G. We say that a subgroup H of G is ${\pi}{\mathfrak{F}}$-embedded in G if there exists a normal subgroup T of G such that HT is s-quasinormal in G and $(H{\cap}T)H_G/H_G{\leq}Z_{{\pi}{\mathfrak{F}}}(G/H_G)$, where $H_G$ is the maximal normal subgroup of G contained in H. In this paper, we use the ${\pi}{\mathfrak{F}}$-embedded subgroups to determine the structures of finite groups. In particular, we give some new characterizations of p-nilpotency and supersolvability of a group.

      • KCI등재

        On $\pi\mathfrak{F}$-embedded subgroups of finite groups

        Wenbin Guo,Haifeng Yu,LI ZHANG 대한수학회 2016 대한수학회보 Vol.53 No.1

        A chief factor $H/K$ of $G$ is called $\mathfrak{F}$-central in $G$ provided $(H/K)\rtimes (G/C_{G}(H/K))\in\mathfrak{F}$. A normal subgroup $N$ of $G$ is said to be $\pi\mathfrak{F}$-hypercentral in $G$ if either $N=1$ or $N\neq1$ and every chief factor of $G$ below $N$ of order divisible by at least one prime in $\pi$ is $\mathfrak{F}$-central in $G$. The symbol $Z_{\pi\mathfrak{F}}(G)$ denotes the $\pi\mathfrak{F}$-hypercentre of $G$, that is, the product of all the normal $\pi\mathfrak{F}$-hypercentral subgroups of $G$. We say that a subgroup $H$ of $G$ is $\pi\mathfrak{F}$-embedded in $G$ if there exists a normal subgroup $T$ of $G$ such that $HT$ is $s$-quasinormal in $G$ and $(H\cap T)H_G/H_G\leq Z_{\pi\mathfrak{F}}(G/H_G)$, where $H_G$ is the maximal normal subgroup of $G$ contained in $H$. In this paper, we use the $\pi\mathfrak{F}$-embedded subgroups to determine the structures of finite groups. In particular, we give some new characterizations of $p$-nilpotency and supersolvability of a group.

      • Study of Large Wind Power Generator with Evaporative Cooling System

        Wang, Haifeng,Li, Wang,Guo, Hui,Yang, Jie,Gu, Guobiao Journal of International Conference on Electrical 2014 Journal of international Conference on Electrical Vol.3 No.1

        Evaporative cooling system has the advantage of high cooling performance, good insulation properties, less electrical fault, easy to maintain and high reliability, can meet the requirements of the cooling system in wind power generators. Based on a large number of theoretical researches and engineering practices, we had a comprehensive study of evaporative cooling wind power generator. Studies show that evaporative cooling system has advantage as the cooling system of wind power generator.

      • KCI등재

        Optimized Non-sinusoidal Power Supply in High-Power Multiphase Induction Motor Drive Based on Harmonic Parameter Analysis

        Wubin Kong,Haifeng Guo,Guangdi Tang,Zhixian Zhong 대한전기학회 2020 Journal of Electrical Engineering & Technology Vol.15 No.6

        A non-sinusoidal power supply is usually applied in a multiphase induction motor drive in order to improve the torque density with harmonic current injection. The harmonic parameters in the motor are essential for harmonic current proportion derivation. In the present work, detailed inductance parameters are derived, and an optimized non-sinusoidal power supply is proposed based on harmonic parameter analysis. The traditional method considers only air-gap fl ux density distribution optimization, while the yoke fl ux density is ignored. The proposed method focuses on optimizing the air-gap fl ux density and yoke fl ux density simultaneously. The proposed method improves the stator iron utilization, and the torque density and effi ciency are enhanced under heavy loads. Finally, 15 kW and 630 kW nine-phase motor drives are constructed, and the proposed non-sinusoidal power supply control strategy is validated experimentally.

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