An Efficient Implementation of Tornado Code for Fault Tolerance

Lei, Jian-Jun,Kwon, Gu-In Korea Spatial Information System Society 2009 한국공간정보시스템학회 논문지 Vol.11 No.2

This paper presents the implementation procedure of encoding and decoding algorithms for Tornado code that can provide fault tolerance for storage and transmission system. The degree distribution satisfying heavy tail distribution is produced. Based on this distribution, a good random irregular bipartite graph is attained after plenty of trails. Such graph construction is proved to be efficient, and the experiments also demonstrate that the implementation obtains good performance in terms of decoding overhead.

A novel recyclable nano-adsorbent for enhanced oil recovery with efficient removal of Ca2+ and Cr6+ from oilfield wastewater

Lei He,Yong Dai,Zhe Wang,Lutao Yang,Luxia Zhang,Pengpeng Hu,Yutian Lei,Hong Mo,Haomiao Zhu,Jun Zhang 한국화학공학회 2022 Korean Journal of Chemical Engineering Vol.39 No.8

Oilfield wastewater has a significantly negative influence on the recovery efficiency due to its hypersalinity. Therefore, magnetic graphene oxide (GO) modified with ethylene diamine tetraacetic acid (EDTA) and grafted bypolyethylene glycol (PEG) nano-adsorbent was prepared to remove the Ca2+ and Cr6+ in Jidong Oilfield wastewaterspecifically. It was noteworthy that PEG-g-EDTA/Fe3O4/GO nano-adsorbent had excellent adsorption performance,with removal ratios up to 71.6% for Ca2+ and 42.7% for Cr6+ at 30 min. After the fifth recycling run, the nano-adsorbentstill remained with high removal ratios (69.3% for Ca2+ and 30.5% for Cr6+) and high reuse rates (89.4% for Ca2+and 95.2% for Cr6+), indicating that the nano-adsorbent had outstanding adsorption-desorption efficacy and high reusability. The adsorption test results demonstrated that the total salinity of the treated oilfield wastewater decreased byabout 5,000 ppm, and the displacement efficiency further increased by 12.5% by chemical flooding compared with theuntreated wastewater. Therefore, PEG-g-EDTA/Fe3O4/GO nano-adsorbent is an adsorbent with excellent potentialwhich can effectively remove Ca2+ and Cr6+ in oilfield wastewater to enhance oil recovery (EOR).

The Effect of Impeller Indent Distance on the Performance of Vortex Pumps

Lei DAI,Lei GU,Jun WANG,Xiang AO,Xiaobo ZHU 한국유체기계학회 2020 International journal of fluid machinery and syste Vol.13 No.1

Low efficiency is an urgent problem to be solved for vortex pumps due to large number of vortices and backflows. This paper concentrates on the performance improvement of vortex pumps caused by changing the indent distance of the impeller. First, a complete numerical model was established by selecting the optimal length of inlet and outlet and appropriate mesh quantity. Then, the reliability of this model was validated by comparing simulation results with experimental data. Based on this model, the internal flows of vortex pumps with different impeller indent distances were observed in simulations and the fitted curves of head and efficiency were created. Finally, the cause of the performance improvement was demonstrated by analyzing the flow field in vortex pumps.

African students’ motivations for studying in China’s higher education

Lei, Jun,Xiao, Longhai,Li, Binrong 서울대학교 교육연구소 2021 Asia Pacific Education Review Vol.22 No.2

As the number of African students in the international education market increases, it is important to understand their motivation to study in China and decision-making process they follow. This study focuses on African students being educated in Hangzhou, a new first-tier city. Using interview data, a tentative model on the push–pull factors affecting African students’ decision-making is presented. The findings show that African students’ decision-making process follows one of two sequences depending on whether they have received advice from others. All African students in China who were interviewed began to consider studying abroad due to personal reasons, recommendation from others, a lack of opportunity nearby, and the poor capacity of local universities along with social instability. For African students who do not have others’ advice to guide them, the subsequent stages of their decision-making process include choosing first to study in China and choosing a city and institution. This decision-making depends in large part on the information available online including program availability, reputation and rank of the university, its academic quality, the image of the city, and the availability of scholarships, the affordability of tuition and the cost of living, and application accessibility. By contrast, those who have access to others’ advice may skip the choice of host country and city, directly choosing the recommended institution.

Chemical composition and in vitro digestibility of corn stover during field exposure and the fermentation characteristics of silage prepared with microbial additives

Jun Lei Gao,Peng Wang,Chang-Hai Zhou,Ping Li,Hong Yu Tang,Jiabao Zhang,Yimin Cai 아세아·태평양축산학회 2019 Animal Bioscience Vol.32 No.12

Objective: To effectively use corn stover resources as animal feed, we explored the chemical composition and in vitro digestibility of corn stover during field exposure and the fermentation characteristics of silage prepared with lactic acid bacteria (LAB) and cellulase. Methods: Corn ears including the cobs and shucks were harvested at the ripe stage. The corn stover was exposed in the field under natural weather conditions. Silages were prepared after 0, 2, 4, 7, 15, 30, and 60 d of exposure. Corn stover was chopped into approximately 1 to 2 cm lengths and then packed into 5 liter plastic silos. The ensiling density was 550.1±20.0 g/L of fresh matter, and the silos were kept at room temperature (10°C to 25°C). Silage treatments were designed as follows: without additives (control), with LAB, with cellulase, and with LAB+ cellulase. After 45 d of fermentation, the silos were opened for chemical composition, fermentation quality and in vitro digestion analyses. Results: After harvest, corn stover contained 78.19% moisture, 9.01% crude protein (CP) and 64.54% neutral detergent fiber (NDF) on a dry matter (DM) basis. During field exposure, the DM, NDF, and acid detergent fiber (ADF) contents of corn stover increased, whereas the CP and water-soluble carbohydrate contents and in vitro digestibility of the DM and CP decreased (p<0.05). Compared to the control silage, cellulase-treated silage had lower (p<0.05) NDF and ADF contents. The pH values were lower in silage treated with LAB, cellulase, or LAB+cellulase, and lactic acid contents were higher (p<0.05) than those of the control. Silage treated with cellulase or LAB+cellulase improved (p<0.05) the in vitro DM digestibility (IVDMD) compared to that of the control or LAB-treated silage. Conclusion: Corn stover silage should be prepared using fresh materials since stover nutrients are lost during field exposure, and LAB and cellulase can improve silage fermentation and IVDMD.

Differences in the mandibular premolar positions in Angle Class I subjects with different vertical facial types

Jun Duan,Feng Deng,Wan-Shan Li,Xue-Lei Li,Lei-Lei Zheng,Gui-Yuan Li,Yan-Jie Bai 대한치과교정학회 2015 대한치과교정학회지 Vol.45 No.4

Objective: To compare the positions of the mandibular premolars in Angle Class I subjects according to vertical facial type. The results will provide a theoretical basis for predicting effective tooth movement in orthodontic treatment. Methods: Cephalometric parameters were determined using cone-beam computed tomography in 120 Angle Class I subjects. Subjects were categorized as short, normal, and long face types according to the Frankfort mandibular angle. Parameters indicating the position of the mandibular right premolars and the mandible were also measured. Results: The angle between the mandibular first premolar axis and buccal cortex, the distance between the root apex and buccal cortex, angle of vestibularization, arc of vestibularization, and root apex maximum movable distance were significantly greater in the short face type than in the long and norm face types. The angle between the mandibular second premolar axis and buccal cortex, the distance from root apex to buccal cortex, and the arc of vestibularization were significantly greater in the short face type than in the normal face type. Conclusions: There are significant differences in the mandibular premolar positions in Class I subjects according to vertical facial type.

Reliable Data Transmission Based on Erasure-resilient Code in Wireless Sensor Networks

( Jian-jun Lei ),( Gu-in Kwon ) 한국인터넷정보학회 2010 KSII Transactions on Internet and Information Syst Vol.4 No.1

Emerging applications with high data rates will need to transport bulk data reliably in wireless sensor networks. ARQ (Automatic Repeat request) or Forward Error Correction (FEC) code schemes can be used to provide reliable transmission in a sensor network. However, the naive ARQ approach drops the whole frame, even though there is a bit error in the frame and the FEC at the bit level scheme may require a highly complex method to adjust the amount of FEC redundancy. We propose a bulk data transmission scheme based on erasure-resilient code in this paper to overcome these inefficiencies. The sender fragments bulk data into many small blocks, encodes the blocks with LT codes and packages several such blocks into a frame. The receiver only drops the corrupted blocks (compared to the entire frame) and the original data can be reconstructed if sufficient error-free blocks are received. An incidental benefit is that the frame error rate (FER) becomes irrelevant to frame size (error recovery). A frame can therefore be sufficiently large to provide high utilization of the wireless channel bandwidth without sacrificing the effectiveness of error recovery. The scheme has been implemented as a new data link layer in TinyOS, and evaluated through experiments in a testbed of Zigbex motes. Results show single hop transmission throughput can be improved by at least 20% under typical wireless channel conditions. It also reduces the transmission time of a reasonable range of size files by more than 30%, compared to a frame ARQ scheme. The total number of bytes sent by all nodes in the multi-hop communication is reduced by more than 60% compared to the frame ARQ scheme.

Sesquiterpenoids with Various Carbocyclic Skeletons from the Flowers of <i>Chrysanthemum indicum</i>

Liu, Lei-Lei,Ha, Thi Kim Quy,Ha, Wei,Oh, Won Keun,Yang, Jun-Li,Shi, Yan-Ping American Society of Pharmacognosy 2017 Journal of natural products Vol.80 No.2

<P>A phytochemical investigation of the flowers of Chrysanthemum indicum yielded sesquiterpenoids 1-25 with various carbocyclic skeletons, including 10 new (1-10) and 15 known (11-25) analogues. The structures were elucidated via their physical data, while the absolute configuration of compounds 6, 8, and 10 was assessed via electronic circular dichroism analysis. The evaluation of the effect of sesquiterpenoids on porcine epidemic diarrhea virus (PEDV) replication showed that compounds 1-5, 12, 14, 16, 17, 19, and 21 increased cell viability against cell death in PEDV-injected cells. Compounds 2, 12, and 17 were selected and investigated for their inhibition of proteins required for PEDV replication. Compounds 2 and 17 significantly reduced PEDV nucleocapsid and spike protein synthesis compared with azauridin as a positive control.</P>

华语电影节庆档的偏向及其文化解读

?俊?(Jun Lei Yang) 중국영화포럼 2016 영화중국 Vol.3 No.1

There are three partialities for Chinese films in festival schedule 2016. With the reflection about The Mermaid, From Vegas to Maocao3 and The Monkey King2, it is necessary to criticize the cultural phenomenon by focalizing on the homogeneity in the schedule, the anti-intellectual technique and the money worship.

Next-generation sequencing of the mitochondrial genome of Dolichovespula panda (Hymenoptera: Vespidae) with a phylogenetic analysis of Vespidae

Xu-Lei Fan,Ya-Jun Gong,Peng-Yan Chen,Qing-Qing Tan,Jiang-Li Tan,Shu-Jun Wei 한국응용곤충학회 2017 Journal of Asia-Pacific Entomology Vol.20 No.3

For the first time the mitochondrial genome of a Dolichovespula species, D. panda Archer (Hymenoptera: Vespidae), was sequenced with a next-generation sequencing approach. The sequenced mitochondrial genome is 17137 bp long and consists of 13 protein-coding, 22 tRNA and two rRNA genes, as well as a partial A +T-rich region. Twenty-two of the genes are encoded on the majority strand and 15 genes on the minority strand. All protein-coding genes start with ATN codons and have a TAA termination codon, except for one with a TA codon. Compared with the putative ancestral arrangement of insects, the D. panda mitochondrial genome shows the shuffling of trnN and trnE, and of trnQ and trnM, the translocation of trnY to upstream of trnI, and of trnL1 to the region between trnS2 and nad1 and a reversal of trnS1. A phylogenetic tree within the Vespidae was reconstructed using the 13 protein-coding mitochondrial genes. This shows a sister group relationship between Dolichovespula and a clade formed by Vespa and Vespula. It also corroborated the position of Eumeninae as sister group of the clade Polistinae +Vespinae.