Mathematical Model of Two-Degree-of-Freedom Direct Drive Induction Motor Considering Coupling Effect

Jikai Si,Lujia Xie,Junbo Han,Haichao Feng,Wenping Cao,Yihua Hu 대한전기학회 2017 Journal of Electrical Engineering & Technology Vol.12 No.3

The two-degree-of-freedom direct drive induction motor, which is capable of linear, rotary and helical motion, has a wide application in special industry such as industrial robot arms. It is inevitable that the linear motion and rotary motion generate coupling effect on each other on account of the high integration. The analysis of this effect has great significance in the research of two-degreeof- freedom motors, which is also crucial to realize precision control of them. The coupling factor considering the coupling effect is proposed and addressed by 3D finite element method. Then the corrected mathematical model is presented by importing the coupling factor. The results from it are verified by 3D finite element model and prototype test, which validates the corrected mathematical model.

Mini-car Positioning by General IMU

Jikai Bi(필계개),Hao Liu(류하오),Jae-Cheon Lee(이재천),Yipeng Wan(만이봉) 유공압건설기계학회 2019 유공압건설기계학회 학술대회논문집 Vol.2019 No.6

Aperiodic Sampled-data Control for Exponential Synchronization of Chaotic Delayed Neural Networks with Exponentially Decaying Gain

Jikai Wang,Xia Huang,Zhen Wang,Jianwei Xia,Hao Shen 제어·로봇·시스템학회 2020 International Journal of Control, Automation, and Vol.18 No.11

This paper studies the exponential synchronization of chaotic delayed neural networks (CDNNs) under aperiodic sampled-data control. First, an aperiodic sampled-data controller with exponentially decaying gain is designed to enlarge the maximum sampling period and the maximum allowable delay while still preserving the stability of the closed-loop system. Then, a novel time-dependent Lyapunov functional that consists of the information of the exponential decay rate η is elaborately designed to analyze the stability of the closed-loop system instead of using the common “change of coordinates” method. With the aid of Lyapunov theory and some inequality techniques, the sufficient conditions are established to guarantee the exponential synchronization of master-slave CDNNs. Based on matrix transformation, the equivalent conditions in LMI form are established to design the feedback gain. Finally, an illustrative example is given to demonstrate the effectiveness of the proposed controller and the obtained synchronization criteria.

A Provable Authenticated Certificateless Group Key Agreement With Constant Rounds

Jikai Teng,Chuankun Wu 한국통신학회 2012 Journal of communications and networks Vol.14 No.1

Group key agreement protocols allow a group of users,communicating over a public network, to establish a shared secret key to achieve a cryptographic goal. Protocols based on certificateless public key cryptography (CL-PKC) are preferred since CL-PKC does not need certificates to guarantee the authenticity of public keys and does not suffer from key escrow of identity-based cryptography. Most previous certificateless group key agreement protocols deploy signature schemes to achieve authentication and do not have constant rounds. No security model has been presented for group key agreement protocols based on CL-PKC. This paper presents a security model for a certificateless group key agreement protocol and proposes a constant-round group key agreement protocol based on CL-PKC. The proposed protocol does not involve any signature scheme, which increases the efficiency of the protocol. It is formally proven that the proposed protocol provides strong AKE-security and tolerates up to n−2malicious insiders for weak MA-security. The protocol also resists key control attack under a weak corruption model.

A Topology Optimization Method for Hybrid Subtractive–Additive Remanufacturing

Jikai Liu,Yufan Zheng,Yongsheng Ma,Ahmed Qureshi,Rafiq Ahmad 한국정밀공학회 2020 International Journal of Precision Engineering and Vol.7 No.5

This paper presents a hybrid subtractive–additive remanufacturing oriented topology optimization method. This method provides a design-for-remanufacturing approach, which offer solutions for product upgrade or repair. To be specific, a used part is first machined to remove material, and then additively deposited of materials on top. In this way, either the function of the part is upgraded or the broken part is repaired. Beneficially, the used part is economically and environment-friendly recycled. This method is developed under the level set framework and innovatively, the layer-wise level set representation of the additive manufacturing part is adopted for self-support and material anisotropy control. Especially for the latter point, the hybrid deposition path, a combination of contour-off set and zig–zag path patterns, is adopted for deposition path planning, which will be concurrently optimized for the best material anisotropy distribution. Therefore, what will be presented in this paper is a novel combination of structural topological design and process planning to derive the optimal hybrid remanufacturing strategy. This is a very novel trial and we have performed experiments to verify its effectiveness.

Effect of Different Environments on Bond Strength of Glass Fiber-Reinforced Polymer and Steel Reinforcing Bars

Jikai Zhou,Xudong Chen,Shixue Chen 대한토목학회 2012 KSCE JOURNAL OF CIVIL ENGINEERING Vol.16 No.6

The long-term durability of Glass Fiber-Reinforced Polymer (GFRP) bars in concrete need to be investigated and analyzed. This paper presents an experimental investigation into comparison of the durability of the bond between GFRP and steel reinforcing bars in concrete under different environment. For all bars, five environmental conditioning media were used. The bond strength after exposure was considered as a measure of durability of the bond between the bars and concrete. Ninety pullout specimens were used to study the effect of different environment on bond strength of GFRP and steel bars to concrete. Experimental results showed no indication of any bond degradation due to the continuous immersion in tap water, alkaline and salt solutions for ninety days. To the contrary the bond strength values of the conditioned specimens were comparable or slightly higher than the bond of the controlled specimens. The acid+chloride solutions have more detrimental effect on bond strength of GFRP bars in concrete. GFRP and steel bars have similar bond strength retention under alkaline environment. And the rate of bond degradation is very slow due to concrete reinforcement. The long-term durability of Glass Fiber-Reinforced Polymer (GFRP) bars in concrete need to be investigated and analyzed. This paper presents an experimental investigation into comparison of the durability of the bond between GFRP and steel reinforcing bars in concrete under different environment. For all bars, five environmental conditioning media were used. The bond strength after exposure was considered as a measure of durability of the bond between the bars and concrete. Ninety pullout specimens were used to study the effect of different environment on bond strength of GFRP and steel bars to concrete. Experimental results showed no indication of any bond degradation due to the continuous immersion in tap water, alkaline and salt solutions for ninety days. To the contrary the bond strength values of the conditioned specimens were comparable or slightly higher than the bond of the controlled specimens. The acid+chloride solutions have more detrimental effect on bond strength of GFRP bars in concrete. GFRP and steel bars have similar bond strength retention under alkaline environment. And the rate of bond degradation is very slow due to concrete reinforcement.

Experimental Study on Internal and External Salt Attack from Seawater and Sea-Sand to Mortars

Jikai Zhou,Xu He 대한토목학회 2021 KSCE JOURNAL OF CIVIL ENGINEERING Vol.25 No.8

Seawater and sea-sand are potential material for concrete in marine environment. This paper aimed to study the influence of internal and external salt attack from seawater and sea-sand on the performance of mortars. Six groups of mortars with different salt attack types were designed. The length, mass, dynamic elastic modulus and pH value of all mortars were measured in the test. The hydrate phase was obtained by thermodynamic simulation, and the phase after 322 days attacked was detected by X-ray diffraction (XRD). Internal seawater and sea-sand attack could improve the early length change of mortars before 28 days. And the early mass growth rate of mortars of seawater mixed mortars was slow. While the influence of seawater and sea-sand on the early dynamic elasticity modulus was limited. The external environment was the main factor affecting the length, mass and dynamic elasticity modulus of mortars after 28 days. Differences of hydrate phases in different mortars were ettringite (AFT), monosulfate, hemicarbonate, monocarbonate, Friedel's salt and Kuzel's salt. The more salt in mixing materials, the larger the volume of hydration solid phase. The salt attack from seawater and sea-sand could increase pH of the simulated solution in mortars. Ettringite and brucite could be clearly observed by XRD in mortars attacked by external seawater, and gypsum and Friedel's salt could be observed in all mortars. It was more reasonable to use mass to evaluate the deterioration degree of the mortars attacked by seawater or sea-sand.

A Provable Authenticated Certificateless Group Key Agreement with Constant Rounds

Teng, Jikai,Wu, Chuankun The Korea Institute of Information and Commucation 2012 Journal of communications and networks Vol.14 No.1

Group key agreement protocols allow a group of users, communicating over a public network, to establish a shared secret key to achieve a cryptographic goal. Protocols based on certificateless public key cryptography (CL-PKC) are preferred since CL-PKC does not need certificates to guarantee the authenticity of public keys and does not suffer from key escrow of identity-based cryptography. Most previous certificateless group key agreement protocols deploy signature schemes to achieve authentication and do not have constant rounds. No security model has been presented for group key agreement protocols based on CL-PKC. This paper presents a security model for a certificateless group key agreement protocol and proposes a constant-round group key agreement protocol based on CL-PKC. The proposed protocol does not involve any signature scheme, which increases the efficiency of the protocol. It is formally proven that the proposed protocol provides strong AKE-security and tolerates up to $n$-2 malicious insiders for weak MA-security. The protocol also resists key control attack under a weak corruption model.

Stress-constrained topology optimization for material extrusion polymer additive manufacturing

Liu Jikai,Yan Jingjing,Yu Huangchao 한국CDE학회 2021 Journal of computational design and engineering Vol.8 No.3

This paper presents a comprehensive numerical and experimental study on stress-constrained topology optimization for Fused Deposition Modeling (FDM) additive manufacturing. The qp method is employed to avoid the singularity issue of stress-constrained problems. The P-norm function with stability transformation is adopted to build the global stress constraint with iterative corrections to eliminate the gap between the maximum local stress and the P-norm stress. The Heaviside projection is employed to generate clear-cut 0–1 designs. Two benchmark examples have been studied with the numerical algorithm. Experiments are performed on the topologically optimized MBB beam to investigate the impact of the FDM process parameters, including deposition path direction, building direction, and slicing layer height, on the resulted structural strength. The stress-constrained designs without and with Heaviside projection are comparatively tested with experiments. The stress-minimization designs subject to different P-norm parameters are compared both numerically and experimentally. Experiments show that the deposition path direction and the building direction evidently affect the derived structural strength. Moreover, overthin structural members may severely degrade the structural strength due to manufacturing and loading uncertainties.

Description of the whole mitochondrial genome of Bhatia longiradiata (Hemiptera, Cicadellidae, Deltocephalinae: Drabescini) and phylogenetic relationship

Lu Jikai,Wang Jiajia,Li Defang,Wang Xianyi,Dai Renhuai 한국유전학회 2023 Genes & Genomics Vol.45 No.1

Background Mitochondrial genomes are extremely conserved in genetic processes and valuable molecular indications for phylogenetic and evolutionary examination, but the mitochondrial genome of Bhatia has not yet been reported. Objective The target of this writing was to clarify the structural module of the mitochondrial genes of Bhatia longiradiata, verify the monophyletic of Drabescini, and explore the phylogenetic relationship between Drabescini with other leafhoppers. Methods We performed sequencing and explanatory note of the mitochondrion of Bhatia longiradiata. The phylogeny relation was created by ML and Bayesian approaches using three dissimilar datasets (PCG12, PCG12rRNA, and AA), which were constructed to discuss the phylogenetic status of Bhatia longiradiata. Results To report the architectural feature of the chondriosome of Bhatia longiradiata is a seal double-stranded annular molecule with 16,122 bp measurement and cover typically 37 genes. Several tandem repetitive units were observed in an AT enrichment area. The analysis showed that the branching relationships among the six trees were generally consistent, and each of the subfamilies was individually clustered into a monophyletic group within Cicadellidae. Bhatia longiradiata and other members of the Drabescini were aggregated into a clade that was situated within the Deltocephalinae. Conclusion The mitochondrial genome of Bhatia longiradiata covers 37 typical genes and a control region, which covers six tandem repeats. All species of Drabescini procedure a clade within Deltocephalinae. Drabescini and Scaphoideini form a branch and show a sister relationship with strong support. Therefore, we support the relegation of Selenocephalinae to a clan within Deltocephalinae.