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An Efficient Downlink MAC Protocol for Multi-User MIMO WLANs
( Kui Liu ),( Changle Li ),( Chao Guo ),( Rui Chen ) 한국인터넷정보학회 2017 KSII Transactions on Internet and Information Syst Vol.11 No.9
Multi-User Multiple-Input Multiple-Output (MU-MIMO) technology has recently attracted significant attention from academia and industry because of it is increasingly important role in improving networks` capacity and data rate. Moreover, MU-MIMO systems for the Fifth Generation (5G) have already been researched. High Quality of Service (QoS) and efficient operations at the Medium Access Control (MAC) layer have become key requirements. In this paper, we propose a downlink MU-MIMO MAC protocol based on adaptive Channel State Information (CSI) feedback (called MMM-A) for Wireless Local Area Networks (WLANs). A modified CSMA/CA mechanism using new frame formats is adopted in the proposed protocol. Specifically, the CSI is exchanged between stations (STAs) in an adaptive way, and a packet selection strategy which can guarantee a fairer QoS for scenarios with differentiated traffic is also included in the MMM-A protocol. We then derive the expressions of the throughput and access delay, and analyze the performance of the protocol. It is easy to find that the MMM-A protocol outperforms the commonly used protocols in terms of the saturated throughput and access delay through simulation and analysis results.
Recovery of Native Protein from Potato Root Water by Expanded Bed Adsorption with Amberlite XAD7HP
Fan-Kui Zeng,Hong Liu,Peng-Jun Ma,Gang Liu 한국생물공학회 2013 Biotechnology and Bioprocess Engineering Vol.18 No.5
Potato root water (PRW) contains ~1.5%protein. In this study, expanded bed adsorption (EBA)chromatography with Amberlite XAD7HP resin adsorbent was used to isolate native protein from crude PRW. The optimal pH and ionic strength for potato protein binding onto Amberlite XAD7HP were 5.0 and 20 mmol/L. The EBA-refined proteins were dried by vacuum freeze drying and spray drying at varying outlet temperatures. Results indicated that low temperature spray drying was the most cost effective method with respect to retaining protease inhibitor activities. The dried protein concentrates appeared bright yellow or dark reddish brown, with a total glycoalkaloid content of ~170 μg/g. The protease inhibitor activity was ~400 mg/g and 11 ~ 12 mg/g for trypsin inhibition and chymotrypsin inhibition, respectively. The results presented here suggest that EBA using Amberlite XAD7HP as the adsorbent is a feasible strategy for the direct adsorption of native protein from crude PRW.
Chuanbo Liu,Yanzhao Zhu,Kui Zhan,Shenghui Guo,Kang Liu 대한기계학회 2021 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.35 No.6
Given that traditional theoretical diagnosis is difficult to use for the accurate prediction of the looseness of bolted joints, this paper will use the support vector machine (SVM) method to solve this problem. The paper establishes a database by studying the loosening mechanism of bolted joints and by collecting the connection information of the fastening points of the vehicle chassis. Key influence features are determined by the information gain value. The average prediction accuracy of the standard SVM model is 76.94 %, which is better than the theoretical diagnosis method. To achieve optimization, the feature weighted support vector machine and the multiple kernel function support vector machine (MKL SVM) are established, and the average prediction accuracy is 82.18 % and 84.19 %, respectively. The fusion weighted support vector machine (FW-MKL SVM) is built by combining the advantages of two weighted optimization SVMs. The average prediction accuracy is 94.5 %, which meets practical engineering requirements.
Luo Kui,Wang Zhifei,Zhuang Kai,Yuan Shishan,Liu Fei,Liu Aihua 생화학분자생물학회 2022 Experimental and molecular medicine Vol.54 No.-
Increased focus has been placed on the role of histone deacetylase inhibitors as crucial players in subarachnoid hemorrhage (SAH) progression. Therefore, this study was designed to expand the understanding of SAH by exploring the downstream mechanism of the histone deacetylase inhibitor suberoylanilide hydroxamic acid (SAHA) in SAH. The expression of TDP-43 in patients with SAH and rat models of SAH was measured. Then, western blot analysis, immunofluorescence staining, and transmission electron microscope were used to investigate the in vitro effect of TDP-43 on a neuronal cell model of SAH established by oxyhemoglobin treatment. Immunofluorescence staining and coimmunoprecipitation assays were conducted to explore the relationship among histone deacetylase 1 (HDAC1), heat shock protein 70 (HSP70), and TDP-43. Furthermore, the in vivo effect of HDAC1 on SAH was investigated in rat models of SAH established by endovascular perforation. High expression of TDP-43 in the cerebrospinal fluid of patients with SAH and brain tissues of rat models of SAH was observed, and TDP-43 accumulation in the cytoplasm and the formation of inclusion bodies were responsible for axonal damage, abnormal nuclear membrane morphology, and apoptosis in neurons. TDP-43 degradation was promoted by the HDAC1 inhibitor SAHA via the acetylation of HSP70, alleviating SAH, and this effect was verified in vivo in rat models. In conclusion, SAHA relieved axonal damage and neurological dysfunction after SAH via the HSP70 acetylation-induced degradation of TDP-43, highlighting a novel therapeutic target for SAH.
H∞ Filtering for Markovian Jump Linear Systems with Uncertain Transition Probabilities
Xi-Kui Liu,Ji-Jing Zhuang,Yan Li 제어·로봇·시스템학회 2021 International Journal of Control, Automation, and Vol.19 No.7
This paper studies the H∞ filtering problem of stochastic linear systems subject to Markovian jump and multiplicative noise. The transition probabilities are considered to be uncertain. A unified form of filters is constructed for both continuous-time and discrete-time stochastic systems. With the new decoupling technique for the coupling terms between Lyapunov matrices and filtering parameters, sufficient conditions of stochastic stability and H∞ performance of filtering error system are derived. Based on these conditions, the filter is designed with lesscoupling matrices and the filter gain matrices are obtained by calculating a set of linear matrix inequalities. Finally, three examples are presented to test the effectiveness of the obtained method.
Zhihao Liu,Kui Qiu,Yu Dong,Zhaobo Jin,Luwei Liu,Jirong Wu 한국화학공학회 2022 Korean Journal of Chemical Engineering Vol.39 No.12
A non-aqueous phase (Sb/Fe/NMP) desulfurization system for the removal of hydrogen sulfide from naturalgas was constructed by introducing SbCl3 and FeCl3 in a specific ratio into N-methylpyrrolidone (NMP). The desulfurizingagent and its sulfur product were characterized, and the absorption pattern of H2S by the system wasinvestigated by static desulfurization experiments. The results indicate that the desulfurizer’s sulfur capacity can reach16 g/L at room temperature and pressure, and that adding the optimum amount of water and appropriate temperatureincrease can assist to increase desulfurization efficiency. The system maintained a sulfur capacity level of more than90% of the initial sulfur capacity after five consecutive desulfurization-regeneration cycles. XRD and XPS spectrogramrevealed that the regenerated solid product was high purity sulfur. Sb3+ is a key component to ensure the effectiveabsorption of H2S. The presence of a moderate amount of Fe3+ can oxidize and absorb small amounts of H2S and promotethe oxidative regeneration of the system. In addition, we combined the obtained experimental data with densityflooding theory (DFT) theoretical calculations to show that the effective coordination of Sb(III) with HS in the NMPenvironment is the main reason for the effective absorption of H2S by the desulfurizer. NMP is not involved in thecoordination absorption process of hydrogen sulfide.