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On Deploying Relays for Connected Indoor Sensor Networks
Yanmin Zhu,Cuiyao Xue,Haibin Cai,Jiadi Yu,Lei Ni,Minglu Li,Bo Li 한국통신학회 2014 Journal of communications and networks Vol.16 No.3
This paper considers the crucial problem of deployingwireless relays for achieving a connected wireless sensor networkin indoor environments, an important aspect related to the managementof the sensor network. Several algorithms have been proposedfor ensuring full sensing coverage and network connectivity. These algorithms are not applicable to indoor environments becauseof the complexity of indoor environments, in which a radiosignal can be dramatically degraded by obstacles such as walls.Wefirst prove theoretically that the indoor relay placement problem isNP-hard. We then predict the radio coverage of a given relay deploymentin indoor environments. We consider two practical scenarios;wire-connected relays and radio-connected relays. For thenetwork with wire-connected relays, we propose an efficient greedyalgorithmto compute the deployment locations of relays for achievingthe required coverage percentage. This algorithm is proved toprovide a Hn factor approximation to the theoretical optimum,whereHn = 1+ 12 +· · ·+ 1n = ln(n)+1, and n is the number ofall grid points. In the network with radio-connected relays, relayshave to be connected in an ad hoc mode. We then propose an algorithmbased on the previous algorithm for ensuring the connectivityof relays. Experimental results demonstrate that the proposedalgorithms achieve better performance than baseline algorithms.
Yanmin Shen,He Wang,Zijun Liu,Weikun Li,Yuhua Liu,Jingjing Li,Hong-Liang Wei,Huayun Han 한국공업화학회 2021 Journal of Industrial and Engineering Chemistry Vol.93 No.-
A new type of water-retaining, slow-release fertilizer (WSF) based on double-network hydrogels wasfabricated via the ion-crosslinking of sodium carboxymethyl cellulose and the free radical polymeriza-tion of polymerizable β-cyclodextrin (MAH-CD), polyethylene glycol dimethacrylate (PEGDA), acrylamide(AM), and acrylic acid (AA) with urea-loaded halloysite as an additive. The effects of the AM to AAmonomer ratio, the halloysite content, the AlCl3 content and the MAH-CD content on the swelling ratiowere studied. Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), andthermogravimetric analysis (TGA) were applied to characterize the structure and properties of the WSF. The swelling behavior and water retention capacity of the fertilizer were investigated using a classicgravimetric method. The experimental results indicated that the presence of halloysite nanotubes clearlyadjusted the swelling and release properties of the WSF. Kinetic modeling indicated that the swellingmechanism and slow release behavior were consistent with a Fickian diffusion mechanism. Form theconsiderations of its properties and raw materials, the fertilizer developed here has a good prospect ofapplication and extension.
Optimization of Stamping Process Parameters Based on Improved GA-BP Neural Network Model
Yanmin Xie,Wei Li,Cheng Liu,Meiyu Du,Kai Feng 한국정밀공학회 2023 International Journal of Precision Engineering and Vol.24 No.7
Reasonable process parameters are the key measures to ensure the quality of stamping products. In order to reduce the risk of cracking and wrinkling of stamping products, an improved genetic algorithm is proposed and used to optimize the weights and thresholds of the BP neural network(BPNN). A surrogate model combining an improved genetic algorithm and BPNN(IGA-BPNN)is developed. Taking double C as the research object, the training samples and test samples are extracted through Latin hypercube. The training output of IGA-BPNN model is obtained by AutoForm simulation, and the mapping relationship between process parameters and forming quality is established. Then the mapping relationship is optimized by IGA to obtain the optimal process parameters. The results show that this method reduces the wrinkling of the flange edge of double C and obviously improves the forming quality.
Wanying Li,Yanmin Su,Zixian Wang,Zhewen Dong,Haokun Chen,Shumei Zhong,Qi Qi Pang,Jia-Le Song 한국식품영양과학회 2021 한국식품영양과학회 학술대회발표집 Vol.2021 No.10
To observe the effect of SA on DSS-induced intestinal fibrosis in mice. The mice were randomly divided into normal, DSS and SA treated DSS mice group. Changes in body weight(BW), blood stool and diarrhea were observed. The serum levels of IL-1β, IL-6, IL-17A, IL-18 and TNF-α were determined by ELISA kits. The protein levels of NLRP3, caspase-1, ASC, IL-1 β, α-SMA, CollagenI, Beclin1, LC3II/I and p62 were detected by Western Blotting assay. Compared with the normal group, SA significantly inhibited the loss of BW and DAI score in colitis mice (P<0.05). H&E and Masson staining assay suggested the SA reduced epithelial cell damage, crypt structure loss, inflammatory cell infiltration, and the fibrogenesis in colon of colitis mice. The serum levels of IL-1β, IL-6, IL-17A, IL-18 and TNF-α were decreased by SA(P<0.05). SA was able to reduce the protein levels of NLRP3, Caspase-1, ASC, IL-1β, α-SMA, Collagen-I, p62, and increased the expressions of Beclin1 and LC3II/I in colitis mice. The study demonstrated that SA can modulate the activity of NLRP3 inflammasome and autophagy pathway to improve DSS induced intaestinal fibrosis in mice.
Guan, Yanmin,Yang, Caihong,Chen, Ping,Zhou, Li The Society of Naval Architects of Korea 2020 International Journal of Naval Architecture and Oc Vol.12 No.-
The numerical simulation of liquid sloshing in the three-dimensional tanks under horizontal excitation and roll excitation was carried out, and the inhibition effect of different baffles on the sloshing phenomenon was investigated. The numerical calculations were carried out by the nonlinear Boundary Element Method (BEM) with Green's theorem based on the potential flow, which was conducted with the governing equation corresponding to the boundaries of each region. The validity of the method was verified by comparing with experimental values and published literatures. The horizontal baffle, the vertical baffle and the T-shaped baffle in the sloshing tanks were investigated respectively, and the baffles' position, dimension and the liquid depth were provided and discussed in detail. It is drawn that the baffle shape plays a non-negligible role in the tank sloshing. The vertical baffle is a more effective way to reduce the sloshing amplitude when the tank is under a horizontal harmonic excitation while the horizontal baffle is a more effective way when the tank is under a roll excitation. The amplitude of free surface elevation at right tank wall decreases with the increasing of the horizontal baffle length and the vertical baffle height. Although the T-shaped baffle has the best suppression effect on tank sloshing under horizontal excitation, it has limited suppression effect under roll excitation and will complicate the sloshing phenomenon when changing baffle height.
Guan, Yanmin,Yang, Caihong,Chen, Ping,Zhou, Li The Society of Naval Architects of Korea 2020 International Journal of Naval Architecture and Oc Vol.12 No.1
The numerical simulation of liquid sloshing in the three-dimensional tanks under horizontal excitation and roll excitation was carried out, and the inhibition effect of different baffles on the sloshing phenomenon was investigated. The numerical calculations were carried out by the nonlinear Boundary Element Method (BEM) with Green's theorem based on the potential flow, which was conducted with the governing equation corresponding to the boundaries of each region. The validity of the method was verified by comparing with experimental values and published literatures. The horizontal baffle, the vertical baffle and the T-shaped baffle in the sloshing tanks were investigated respectively, and the baffles' position, dimension and the liquid depth were provided and discussed in detail. It is drawn that the baffle shape plays a non-negligible role in the tank sloshing. The vertical baffle is a more effective way to reduce the sloshing amplitude when the tank is under a horizontal harmonic excitation while the horizontal baffle is a more effective way when the tank is under a roll excitation. The amplitude of free surface elevation at right tank wall decreases with the increasing of the horizontal baffle length and the vertical baffle height. Although the T-shaped baffle has the best suppression effect on tank sloshing under horizontal excitation, it has limited suppression effect under roll excitation and will complicate the sloshing phenomenon when changing baffle height.
Shusen Zhao,Yanmin Li 한국정밀공학회 2023 International Journal of Precision Engineering and Vol.24 No.6
When manufacturing aluminum alloy space-frame radomes, the vertical welding distortion is the main factor that affects assembly accuracy, and the residual stress affects the service performance. This paper aims to decrease welding distortion while ensuring that the residual stress is within the appropriate range by adjusting welding direction and sequence. The thermal-elastic–plastic finite element method is used to predict the welding distortion and residual stress in mid-thick aluminum plate-sleeve structures. The numerical model was verified by experimental results of temperature, vertical distortion, and residual stresses. The effect of welding direction and sequence on the distortion and residual stress was examined by the numerical model. Results indicate that the welding direction significantly affects the distribution and magnitude of X-direction distortion (longitudinal shrinkage) but has little effect on vertical distortion and residual stress. The welding sequence significantly affects the magnitude of vertical distortion and the distribution of residual stress. Then, considering the vertical distortion and residual stress, a scheme (Case 3) is recommended for welding mid-thick aluminum plate-sleeve structures. The maximum vertical distortion of the current production scheme (Case 1) and final determined scheme (Case 3) are 5.43 mm and 2.73 mm, and the corresponding maximum tensile residual stress is 186.5 MPa and 193.8 MPa, respectively. Comparing Case 1 with Case 3, Case 3 can reduce the vertical distortion by 49.7%, while the maximum tensile residual stress of the two is close, and the difference is less than 10 MPa.
Shusen Zhao,Yanmin Li,Rui Huang,Zhanshu He 대한기계학회 2021 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.35 No.11
In this paper, three methods of adding and activating weld bead elements, i.e., adding and activating the weld bead segment by segment (case A), adding and activating one weld pass after another (case B), and modified adding and activating one weld pass after another (case C), were employed to establish the corresponding simulation model of a butt joint of AA6061-T6 mid-thick plate with a double-pass weld by ABAQUS. The welding temperature field, residual stress field, and welding deformation were simulated. The heat loss of three methods in the welding simulation was tested by theoretical calculation. To verify the simulation results, the metal-inert gas (MIG) welding experiment was also performed, and the molten pool dimensions, residual stress, and welding deformation were measured. The results show both cases A and C can be effectively employed to predict residual stress, and case C can also save computing time. Case A can more accurately predict the welding deformation.