Applying a sensor energy supply communication scheme to big data opportunistic networks

( Zhigang Chen ),( Jia Wu ) 한국인터넷정보학회 2016 KSII Transactions on Internet and Information Syst Vol.10 No.5

Energy consumption is an important index in mobile ad hoc networks. Data packet transmission increases among nodes, particularly in big data communication. However, nodes may be unable to transmit data packets because of energy over-consumption. Consequently, information may be lost and network communication may block. While opportunistic network is a kind of mobile ad hoc networks, researchers do not focus on energy consumption in opportunistic network communication. This study proposed an effective sensor energy supply scheme that can be applied in opportunistic networks. This scheme considers nodes sensor requests and communication model. In this scheme, nodes do not only accomplish energy supply in communication, but also extend communication time in opportunistic networks. Compared with the Spray and Wait algorithm and the Binary Spray and Wait algorithm in simulations, the proposed scheme extends communication time, increases data packet transmission, and accomplishes energy supply among nodes.

Cross Layer Optimal Design with Guaranteed Reliability under Rayleigh block fading channels

( Xue Chen ),( Yanling Hu ),( Anfeng Liu ),( Zhigang Chen ) 한국인터넷정보학회 2013 KSII Transactions on Internet and Information Syst Vol.7 No.12

Configuring optimization of wireless sensor networks, which can improve the network performance such as utilization efficiency and network lifetime with minimal energy, has received considerable attention in recent years. In this paper, a cross layer optimal approach is proposed for multi-source linear network and grid network under Rayleigh block-fading channels, which not only achieves an optimal utility but also guarantees the end-to-end reliability. Specifically, in this paper, we first strictly present the optimization method for optimal nodal number N*, nodal placement d* and nodal transmission structure p* under constraints of minimum total energy consumption and minimum unit data transmitting energy consumption. Then, based on the facts that nodal energy consumption is higher for those nodes near the sink and those nodes far from the sink may have remaining energy, a cross layer optimal design is proposed to achieve balanced network energy consumption. The design adopts lower reliability requirement and shorter transmission distance for nodes near the sink, and adopts higher reliability requirement and farther transmission distance for nodes far from the sink, the solvability conditions is given as well. In the end, both the theoretical analysis and experimental results for performance evaluation show that the optimal design indeed can improve the network lifetime by 20-50%, network utility by 20% and guarantee desire level of reliability.

Biotemplate Synthesis of Micron Braid Structure CeO₂-TiO₂ Composite and Analysis of its Catalytic Behavior for CO Oxidation

Wang, Chencheng,Jing, Lutian,Chen, Mengpin,Meng, Zeda,Chen, Zhigang,Chen, Feng,Oh, Won-Chun The Korean Ceramic Society 2017 한국세라믹학회지 Vol.54 No.1

A series of $CeO_2-TiO_2$ composite samples with different Ce/Ti molar ratios were prepared by the paper template. Powder X-ray diffraction (XRD) and transmission electron microscopy (TEM) were used to confirm a face-centered cubic lattice of $CeO_2$ with Ce/Ti =8:2 or 9:1 and a two phase mixture of anatase titania and face-centered cubic ceria with Ce/Ti = 7 : 3. The field emission scanning electron microscopy (FESEM) results suggest that the products are micron braid structures consisting of fibers with diameters in a range of $1-6{\mu}m$ and lengths of several hundred micrometers. $N_2$ absorption-desorption testing shows that the composite at Ce/Ti molar fraction of 8 : 2 has the largest BET surface area (about $81m^2{\cdot}g^{-1}$). Compared to the pure $CeO_2$ sample, the composites show superior catalytic activity for $H_2$ reduction and CO oxidation. For the micron braid structure $CeO_2-TiO_2$ composite (Ce/Ti = 8 : 2), due to the high surface area and the solid solution with appropriate $Ti^{4+}$ incorporation, the CO conversion at about $280^{\circ}C$ was above 50% and at $400^{\circ}C$ was 100%.

Cellular Traffic Offloading through Opportunistic Communications Based on Human Mobility

( Zhigang Li ),( Yan Shi ),( Shanzhi Chen ),( Jingwen Zhao ) 한국인터넷정보학회 2015 KSII Transactions on Internet and Information Syst Vol.9 No.3

The rapid increase of smart mobile devices and mobile applications has led to explosive growth of data traffic in cellular network. Offloading data traffic becomes one of the most urgent technical problems. Recent work has proposed to exploit opportunistic communications to offload cellular traffic for mobile data dissemination services, especially for accepting large delayed data. The basic idea is to deliver the data to only part of subscribers (called target-nodes) via the cellular network, and allow target-nodes to disseminate the data through opportunistic communications. Human mobility shows temporal and spatial characteristics and predictability, which can be used as effective guidance efficient opportunistic communication. Therefore, based on the regularity of human mobility we propose NodeRank algorithm which uses the encounter characteristics between nodes to choose target nodes. Different from the existing work which only using encounter frequency, NodeRank algorithm combined the contact time and inter-contact time meanwhile to ensure integrity and availability of message delivery. The simulation results based on real-world mobility traces show the performance advantages of NodeRank in offloading efficiency and network redundant copies.

SIMULATION AND MODELING OF DYNAMIC FRICTION COEFFICIENT OF WET CLUTCH DURING ENGAGEMENT

Zhigang Zhang,Ling Zou,Hang Liu,Yonglong Chen,Benzhu Zhang 한국자동차공학회 2022 International journal of automotive technology Vol.23 No.1

A dynamic friction coefficient model in engagement was established based on the friction transmission mechanism of a wet clutch. The effects of parameters, such as the material permeability, surface roughness, Young’s modulus, ATF viscosity, applied pressure, initial relative angular velocity, and pressure delay time, on the friction coefficient during engagement were investigated. The results indicated that material permeability has a greater influence on the time when the dynamic friction coefficient tends to be stable, choosing an appropriate permeability of friction material can effectively prevent excessive the level of jerk during the engagement and excessive engagement time. Surface roughness and applied pressure mainly affect the magnitude of the initial and midpoint friction coefficients. Appropriately increasing the surface roughness and applied pressure can increase the smoothness of the engagement of wet clutch. The ATF viscosity and initial relative angular velocity have a significant effect on the magnitude of the initial friction coefficients. Appropriately increasing the ATF viscosity and initial relative angular velocity will reduce the level of jerk at the end of the wet clutch engagement. Young’s modulus and the pressure delay time have a smaller effect on the dynamic friction coefficient than that of other parameters.

Adsorption mechanism of lead ions at ilmenite/water interface and its influence on ilmenite flotability

Pan Chen,Jihua Zhai,Wei Sun,Yue-hua Hu,Zhigang Yin,Xiangsheng Lai 한국공업화학회 2017 Journal of Industrial and Engineering Chemistry Vol.53 No.-

In order to get further understanding of lead ions adsorption onto ilmenite surface, zeta potential analysis, adsorption density calculation, FT-IR and XPS analysis were employed. The results showed that the adsorption of lead ions onto ilmenite surface was a chemically dominating process. Lead species could interact with iron-hydroxyl complex compounds to form a Fe–O–Pb complex. The hydrophobic complex of Pb(OL)2 was also observed. Iron and adsorbed lead ions on ilmenite surface served as the main active-sites via chemisorption with oleate species. Introducing lead ions, as a surface modification means, can efficiently improve ilmenite flotability.

RNA Interference to Prevent Bombyx mori Nuclear Polyhedrosis Virus Infection in Vivo

Hu Zhigang,Chen Keping,Gao Lu,Yao Qin Korean Society of Sericultural Science 2006 International Journal of Industrial Entomology Vol.12 No.1

RNA interference has been used as a powerful tool in preventing virus proliferation in many species. In this study, we injected the dsRNA in vitro transcripts into Bombyx mori to investigate the resistance to B. mori nuclear polyhedrosis virus (BmNPV). Through vivisectional observation and real-time quantities PCR analysis, we found that these dsRNA can prevent the BmNPV to a certain extent, and delay the viruses' proliferation.

Comments on the Paper "Simulation of the Aromatic Recovery Process by Extractive Distillation" : (Ko, M., Na, S., Cho, J. and Kim, H., Korean J. Chem. Eng., 19(6), (2002), 996-1000)

Lei, Zhigang,Li, Chengyue,Chen, Biaohua 한국화학공학회 2003 Korean Journal of Chemical Engineering Vol.20 No.6

Clinical characteristics of choledochal cysts with intrahepatic bile duct dilatations: an observational study

Ken Chen,Shuhao Zhang,Duote Cai,Yuebin Zhang,Yi Jin,Wenjuan Luo,Zongwei Huang,Di Hu,Zhigang Gao 대한외과학회 2024 Annals of Surgical Treatment and Research(ASRT) Vol.106 No.4

Purpose: Whether a dilated intrahepatic bile duct (IHBD) has any effect on the prognosis of choledochal cyst (CC) remains controversial. We aimed to summarize the clinical characteristics and prognosis of CC with IHBD dilatation. Methods: One hundred ninety-two children diagnosed with CC were identified, including 127 without IHBD dilatation (group A) and 65 with IHBD dilatation (group B). A retrospective analysis was performed to explore the clinical characteristics and prognosis of CC with IHBD dilatation based on clinical indices, symptoms, and complications. Results: Compared with group A, incidences of jaundice and fever were higher in group B (P = 0.010 and P = 0.033). Preoperative total bilirubin, direct bilirubin, and indirect bilirubin were increased in group B compared to group A (P = 0.005, P < 0.001, and P = 0.014), as were preoperative ALT, AST, γ-GT, and total bile acid (P = 0.006, P = 0.025, P < 0.001, and P = 0.024). The risk of liver fibrosis or cirrhosis was significantly increased for group B compared with group A (P = 0.012) and also occurred earlier in group B (P = 0.006). In the dilated IHBDs, 95.4% (62 of 65) recovered to normal, and more than half of dilated IHBDs (37 of 65) recovered to normal in 1 week. Conclusion: Most IHBDs can recover to normal postoperatively in a short time, and proactive treatment is recommended for CC patients with IHBD dilatation for significant abnormal liver functions.

Factors controlling the geochemical differences between two types of rhyolites in the middle Okinawa Trough

Yuxiang Zhang,Zhigang Zeng,Xiaoyuan Wang,Shuai Chen,Xuebo Yin 한국지질과학협의회 2020 Geosciences Journal Vol.24 No.1

The origin of the felsic volcanic rocks in the Okinawa Trough (OT) remains uncertain. In the middle Okinawa Trough (MOT), two types of rhyolites (type 1 and type 2 rhyolites) have been recognized. Research on the diverse volcanic rocks should be prioritized to determine the magmatic origins of these rocks. Consequently, in this article, the geochemical differences and controlling factors for these two types of MOT rhyolites are systematically discussed. Type 2 rhyolites have higher Dy/Yb and Nb/Ta ratios than type 1 rhyolites, implying that the former might be influenced by a greater contribution of amphibole. Quantitative models suggest that type 1 rhyolites could have formed via the remelting of andesites when amphiboles remain in the source, whereas type 2 rhyolites could have formed without residual amphiboles. These two distinct melting models effectively explain most discrepancies between the major and trace element compositions of type 1 and 2 rhyolites. Additionally, the lower Mg# and δEu values of type 2 rhyolites are partly caused by significant magmatic differentiation. Quasi-linear correlations between some major oxides, trace element ratios and Sr-Nd isotopic ratios for type 2 rhyolites suggest that these rhyolites might have been contaminated by crustal rocks or melts with compositions similar to those of the Kueishantao (KST) andesites or the Middle Miocene upper crustal rocks of SW Japan. Therefore, isotopically enriched crustal materials likely remain in the OT crust.