The Research on Influence Factors of Agricultural Products Logistics in Mainland China-The Empirical Analysis based on the Data During 2000-2014

Sheng Zhong 보안공학연구지원센터 2016 International Journal of u- and e- Service, Scienc Vol.9 No.10

Low efficiency of agricultural products logistics has become one of “bottlenecks” to restrict the further development of agricultural industrialization and rural economy in China. In this paper, upstream-downstream industries factors of agricultural products supply chain is innovatively absorbed into the influence factors framework. And then DEA-SBM model, regression analysis method and DEA-TOBIT model are applied to measure agricultural products logistics efficiency and analyze the three categories of influence factors. The research results show that During two periods of time, the TE level on a national scale was very low, which was basically in the state of inefficiency, which was mainly due to low PTE. Because the PTE is low and the development of agricultural products logistics of most of provincial administrative regions in Mainland China has reached the stage of constant or decreasing scale merit, the enlargement of agricultural production scale can improve the growth of TE level of agricultural products logistics to a certain extent, but the function is not remarkable. On the contrary, the negative relationship has been displayed between the expansion of farming industry scale and agricultural retail businesses and the TE level of agricultural products logistics. Because of the diversityin regional social and environmental factors, the impact of exogenous environmental factors on the TE level of three regions show a certain difference.

Policy Adjuster-driven Grid Workflow Management for Collaborative Heart Disease Identification System

Deng, Shengzhong,Youn, Chan-Hyun,Liu, Qi,Kim, Hoe-Young,Yu, Taoran,Kim, Young-Hun Korea Information Processing Society 2008 Journal of information processing systems Vol.4 No.3

This paper proposes a policy adjuster-driven Grid workflow management system for collaborative healthcare platform, which supports collaborative heart disease diagnosis applications. To select policies according to service level agreement of users and dynamic resource status, we devised a policy adjuster to handle workflow management polices and resource management policies using policy decision scheme. We implemented this new architecture with workflow management functions based on policy quorum based resource management system for providing poincare geometrycharacterized ECG analysis and virtual heart simulation service. To evaluate our proposed system, we executed a heart disease identification application in our system and compared the performance to that of the general workflow system and PQRM system under different types of SLA.

VirtAV: an Agentless Runtime Antivirus System for Virtual Machines

( Hongwei Tang ),( Shengzhong Feng ),( Xiaofang Zhao ),( Yan Jin ) 한국인터넷정보학회 2017 KSII Transactions on Internet and Information Syst Vol.11 No.11

Antivirus is an important issue to the security of virtual machine (VM). According to where the antivirus system resides, the existing approaches can be categorized into three classes: internal approach, external approach and hybrid approach. However, for the internal approach, it is susceptible to attacks and may cause antivirus storm and rollback vulnerability problems. On the other hand, for the external approach, the antivirus systems built upon virtual machine introspection (VMI) technology cannot find and prohibit viruses promptly. Although the hybrid approach performs virus scanning out of the virtual machine, it is still vulnerable to attacks since it completely depends on the agent and hooks to deliver events in the guest operating system. To solve the aforementioned problems, based on in-memory signature scanning, we propose an agentless runtime antivirus system VirtAV, which scans each piece of binary codes to execute in guest VMs on the VMM side to detect and prevent viruses. As an external approach, VirtAV does not rely on any hooks or agents in the guest OS, and exposes no attack surface to the outside world, so it guarantees the security of itself to the greatest extent. In addition, it solves the antivirus storm problem and the rollback vulnerability problem in virtualization environment. We implemented a prototype based on Qemu/KVM hypervisor and ClamAV antivirus engine. Experimental results demonstrate that VirtAV is able to detect both user-level and kernel-level virus programs inside Windows and Linux guest, no matter whether they are packed or not. From the performance aspect, the overhead of VirtAV on guest performance is acceptable. Especially, VirtAV has little impact on the performance of common desktop applications, such as video playing, web browsing and Microsoft Office series.

Stability Analysis of External Ramp Compensation on Valley V² Controlled Boost Converter

Haoyang Gan,Shengzhong He,Xiaoqiong He,Songrong Wu,Ping Yang,Minrui Leng 전력전자학회 2019 ICPE(ISPE)논문집 Vol.2019 No.5

V² control has fast transient response so it has been widely used voltage regulator modules. Although valley V² control has been proposed to control boost converter, there still exist instability issues. To stabilize instability caused by small duty or equivalent series resistance of output capacitor, external ramp compensation has been used. However, there is no reference for choosing proper ramp slope. In this paper, a discrete iterative model of valley V² controlled boost converter with external ramp compensation is established. Based on the model, bifurcation behaviors under different duty cycle and ESR are observed as equivalent ramp slope increases. The orbit of converter transfers from chaos to multi-period then to period-1, consistent with maximal Lyapunov exponent. By analyzing loci of eigenvalues, stability boundaries in different operation regions are obtained to guide equivalent ramp slope design. Experimental prototype is also built up to verify the theoretical analysis.

IOMMU Para-Virtualization for Efficient and Secure DMA in Virtual Machines

( Hongwei Tang ),( Qiang Li ),( Shengzhong Feng ),( Xiaofang Zhao ),( Yan Jin ) 한국인터넷정보학회 2016 KSII Transactions on Internet and Information Syst Vol.10 No.12

IOMMU is a hardware unit that is indispensable for DMA. Besides address translation and remapping, it also provides I/O virtual address space isolation among devices and memory access control on DMA transactions. However, currently commodity virtualization platforms lack of IOMMU virtualization, so that the virtual machines are vulnerable to DMA security threats. Previous works focus only on DMA security problem of directly assigned devices. Moreover, these solutions either introduce significant overhead or require modifications on the guest OS to optimize performance, and none can achieve high I/O efficiency and good compatibility with the guest OS simultaneously, which are both necessary for production environments. However, for simulated virtual devices the DMA security problem also exists, and previous works cannot solve this problem. The reason behind that is IOMMU circuits on the host do not work for this kind of devices as DMA operations of which are simulated by memory copy of CPU. Motivated by the above observations, we propose an IOMMU para-virtualization solution called PVIOMMU, which provides general functionalities especially DMA security guarantees for both directly assigned devices and simulated devices. The prototype of PVIOMMU is implemented in Qemu/KVM based on the virtio framework and can be dynamically loaded into guest kernel as a module, As a result, modifying and rebuilding guest kernel are not required. In addition, the device model of Qemu is revised to implement DMA access control by separating the device simulator from the address space of the guest virtual machine. Experimental evaluations on three kinds of network devices including Intel I210 (1Gbps), simulated E1000 (1Gbps) and IB ConnectX-3 (40Gbps) show that, PVIOMMU introduces little overhead on DMA transactions, and in general the network I/O performance is close to that in the native KVM implementation without IOMMU virtualization.

IOMMU Para-Virtualization for Efficient and Secure DMA in Virtual Machines

Tang, Hongwei,Li, Qiang,Feng, Shengzhong,Zhao, Xiaofang,Jin, Yan Korean Society for Internet Information 2016 KSII Transactions on Internet and Information Syst Vol.10 No.12

IOMMU is a hardware unit that is indispensable for DMA. Besides address translation and remapping, it also provides I/O virtual address space isolation among devices and memory access control on DMA transactions. However, currently commodity virtualization platforms lack of IOMMU virtualization, so that the virtual machines are vulnerable to DMA security threats. Previous works focus only on DMA security problem of directly assigned devices. Moreover, these solutions either introduce significant overhead or require modifications on the guest OS to optimize performance, and none can achieve high I/O efficiency and good compatibility with the guest OS simultaneously, which are both necessary for production environments. However, for simulated virtual devices the DMA security problem also exists, and previous works cannot solve this problem. The reason behind that is IOMMU circuits on the host do not work for this kind of devices as DMA operations of which are simulated by memory copy of CPU. Motivated by the above observations, we propose an IOMMU para-virtualization solution called PVIOMMU, which provides general functionalities especially DMA security guarantees for both directly assigned devices and simulated devices. The prototype of PVIOMMU is implemented in Qemu/KVM based on the virtio framework and can be dynamically loaded into guest kernel as a module, As a result, modifying and rebuilding guest kernel are not required. In addition, the device model of Qemu is revised to implement DMA access control by separating the device simulator from the address space of the guest virtual machine. Experimental evaluations on three kinds of network devices including Intel I210 (1Gbps), simulated E1000 (1Gbps) and IB ConnectX-3 (40Gbps) show that, PVIOMMU introduces little overhead on DMA transactions, and in general the network I/O performance is close to that in the native KVM implementation without IOMMU virtualization.

Polydopamine Used as Hollow Capsule and Core-Shell Structures for Multiple Applications

Xinyu Cui,Yuanyuan Yin,Zuo Ma,Yongkui Yin,Yue Guan,Shengzhong Rong,Jinxia Gao,Yingying Niu,Miaojing Li 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2015 NANO Vol.10 No.5

Polydopamine (PDA) capsule and core – shell structures with tailored structures and properties are of particular interests due to their multifunctions and potential applications as new colloidal structures in diverse fields. Among the available fabrication methods, PDA film onto colloidal particles followed by selective template removal has attracted extensive attention due to its advantages of precise control over the size, wall thickness and functions of the obtained capsules. The past several years has witnessed a rapid increase of research concerning the new fabrication strategies, functionalization and applications of this kind of capsules and core – shell structures, particularly in many fields such as drug delivery, catalysis, antibacterial, etc. In this review, the very recent progress of the capsule and core – shell structures based on PDA are summarized. There are basically two sections, including the fabrication process of PDA capsules, core – shell structures, and the various applications based on PDA.

Analysis of the DNA Methylation of Maize (Zea mays L.) in Response to Cold Stress Based on Methylation-sensitive Amplified Polymorphisms

Xiaohui Shan,Xiaoyu Wang,Guang Yang,Ying-Wu Lan,Shengzhong Su,Shipeng Li,Hongkui Liu,Yaping Yuan 한국식물학회 2013 Journal of Plant Biology Vol.56 No.1

DNA methylation plays a vital role in tuning geneexpression in response to environmental stimuli. Here,methylation-sensitive amplified polymorphisms (MSAP)were used to assess the effect of cold stress on the extent andpatterns of DNA methylation in maize seedlings. Overall,cold-induced genome-wide DNA methylation polymorphismsaccounted for 32.6 to 34.8% of the total bands at the differenttreatment time-points. It was demonstrated that the extentand pattern of DNA methylation was induced by cold stressthrough the cold treatment process and that thedemethylation of fully methylated fragments was the maincontributor of the DNA methylation alterations. The sequencesof 28 differentially amplified fragments relevant to stresswere successfully obtained. Under the cold stress, demethylationwas detected in most fragments. BLAST results indicate thatthe homologues of these fragments are involved in manyprocesses, including hormone regulation, cold response,photosynthesis, and transposon activation. The expressionanalysis demonstrated an increase in the transcription of fivedemethylated genes. Despite the fact that DNA methylationchanges and cold acclimation are not directly associated, ourresults may indicate that the specific demethylation of genesis an active and rapid epigenetic response to cold in maizeduring the seedling stage, further elucidating the mechanismof maize adaptation to cold stress.