• 제목/요약/키워드: Physical Host

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NDynamic Framework for Secure VM Migration over Cloud Computing

  • Rathod, Suresh B.;Reddy, V. Krishna
    • Journal of Information Processing Systems
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    • v.13 no.3
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    • pp.476-490
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    • 2017
  • In the centralized cloud controlled environment, the decision-making and monitoring play crucial role where in the host controller (HC) manages the resources across hosts in data center (DC). HC does virtual machine (VM) and physical hosts management. The VM management includes VM creation, monitoring, and migration. If HC down, the services hosted by various hosts in DC can't be accessed outside the DC. Decentralized VM management avoids centralized failure by considering one of the hosts from DC as HC that helps in maintaining DC in running state. Each host in DC has many VM's with the threshold limit beyond which it can't provide service. To maintain threshold, the host's in DC does VM migration across various hosts. The data in migration is in the form of plaintext, the intruder can analyze packet movement and can control hosts traffic. The incorporation of security mechanism on hosts in DC helps protecting data in migration. This paper discusses an approach for dynamic HC selection, VM selection and secure VM migration over cloud environment.

Implementation of Memory Efficient Flash Translation Layer for Open-channel SSDs

  • Oh, Gijun;Ahn, Sungyong
    • International journal of advanced smart convergence
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    • v.10 no.1
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    • pp.142-150
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    • 2021
  • Open-channel SSD is a new type of Solid-State Disk (SSD) that improves the garbage collection overhead and write amplification due to physical constraints of NAND flash memory by exposing the internal structure of the SSD to the host. However, the host-level Flash Translation Layer (FTL) provided for open-channel SSDs in the current Linux kernel consumes host memory excessively because it use page-level mapping table to translate logical address to physical address. Therefore, in this paper, we implemente a selective mapping table loading scheme that loads only a currently required part of the mapping table to the mapping table cache from SSD instead of entire mapping table. In addition, to increase the hit ratio of the mapping table cache, filesystem information and mapping table access history are utilized for cache replacement policy. The proposed scheme is implemented in the host-level FTL of the Linux kernel and evaluated using open-channel SSD emulator. According to the evaluation results, we can achieve 80% of I/O performance using the only 32% of memory usage compared to the previous host-level FTL.

Microbiome-Linked Crosstalk in the Gastrointestinal Exposome towards Host Health and Disease

  • Moon, Yuseok
    • Pediatric Gastroenterology, Hepatology & Nutrition
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    • v.19 no.4
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    • pp.221-228
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    • 2016
  • The gastrointestinal exposome represents the integration of all xenobiotic components and host-derived endogenous components affecting the host health, disease progression and ultimately clinical outcomes during the lifespan. The human gut microbiome as a dynamic exposome of commensalism continuously interacts with other exogenous exposome as well as host sentineling components including the immune and neuroendocrine circuit. The composition and diversity of the microbiome are established on the basis of the luminal environment (physical, chemical and biological exposome) and host surveillance at each part of the gastrointestinal lining. Whereas the chemical exposome derived from nutrients and other xenobiotics can influence the dynamics of microbiome community (the stability, diversity, or resilience), the microbiomes reciprocally alter the bioavailability and activities of the chemical exposome in the mucosa. In particular, xenobiotic metabolites by the gut microbial enzymes can be either beneficial or detrimental to the host health although xenobiotics can alter the composition and diversity of the gut microbiome. The integration of the mucosal crosstalk in the exposome determines the fate of microbiome community and host response to the etiologic factors of disease. Therefore, the network between microbiome and other mucosal exposome would provide new insights into the clinical intervention against the mucosal or systemic disorders via regulation of the gut-associated immunological, metabolic, or neuroendocrine system.

Optimizing Garbage Collection Overhead of Host-level Flash Translation Layer for Journaling Filesystems

  • Son, Sehee;Ahn, Sungyong
    • International Journal of Internet, Broadcasting and Communication
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    • v.13 no.2
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    • pp.27-35
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    • 2021
  • NAND flash memory-based SSD needs an internal software, Flash Translation Layer(FTL) to provide traditional block device interface to the host because of its physical constraints, such as erase-before-write and large erase block. However, because useful host-side information cannot be delivered to FTL through the narrow block device interface, SSDs suffer from a variety of problems such as increasing garbage collection overhead, large tail-latency, and unpredictable I/O latency. Otherwise, the new type of SSD, open-channel SSD exposes the internal structure of SSD to the host so that underlying NAND flash memory can be managed directly by the host-level FTL. Especially, I/O data classification by using host-side information can achieve the reduction of garbage collection overhead. In this paper, we propose a new scheme to reduce garbage collection overhead of open-channel SSD by separating the journal from other file data for the journaling filesystem. Because journal has different lifespan with other file data, the Write Amplification Factor (WAF) caused by garbage collection can be reduced. The proposed scheme is implemented by modifying the host-level FTL of Linux and evaluated with both Fio and Filebench. According to the experiment results, the proposed scheme improves I/O performance by 46%~50% while reducing the WAF of open-channel SSDs by more than 33% compared to the previous one.

Effect of rearing season, host plants and their interaction on economical traits of tropical tasar silkworm, Antheraea mylitta Drury- an overview

  • Bhatia, Narendra Kumar;Yousuf, Mohammad
    • International Journal of Industrial Entomology and Biomaterials
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    • v.29 no.1
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    • pp.93-119
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    • 2014
  • Tropical tasar silkworm, Antheraea mylitta (Lepidoptera: Saturniidae) is a polyphagous silk producing forest silkworm of commercial importance in India. Forest dependent people rear its larvae on different forestry host plants twice or thrice in a year for small household income. Larvae of A. mylitta feeds on many forest tree species, but always show a great degree of selectivity as a function of its behavioural responses to physical structure and chemical features of the host plants. Cocoon crop of A. mylitta is influenced by heterogeneity of tasar food plants and climatic conditions of the habitat. The role of host plants, temperature, humidity, rainfall, photoperiod and climatic variables on the growth and development of insects have clearly been demonstrated. This article entails an in-depth analysis on ecological and nutritional aspects of A. mylitta, which may provide selective information to researcher and forest managers, who are particularly associated with livelihood improvement of the poor people in forested area through location specific forest insect industry.

Fast-fashion retailers - Types of online-based internationalization -

  • Lee, Jung Eun
    • The Research Journal of the Costume Culture
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    • v.27 no.1
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    • pp.33-45
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    • 2019
  • This study identified types of online retail internationalization in the fast-fashion context and proposed driving factors of retailers' choices in online-based market entry following the logic of the Uppsala model and the eclectic theory. In particular, this study proposes three types of online-based internationalization: 1) entering a host market with a physical store first, and then expanding with an online store, 2) entering a foreign market with an online store, then expanding to physical stores, and 3) entering only with an online business. In addition, this study investigated the causal factors, ownership-specific and location advantages, that influence the choice of the type of developmental process of online-based internationalization. To develop theoretical and managerial insights into the issue researched, this study employed a qualitative research design involving case studies of three European fast-fashion retailers, H&M, TOPSHOP, and ASOS. This study suggested that fast-fashion retailers that enter a host market with high ownership-specific advantages are likely to choose to enter the market with physical stores and then expand with online stores. On the other hand, when faced with uncertainties attributable to low ownership-specific or location advantages, fast-fashion retailers are likely to choose to enter with an online store first and then expand with physical stores as conditions change. Consequently, this study provides a better understanding for fast-fashion retailers who are willing to expand their businesses to foreign markets via online stores.

A Development of Adaptive VM Migration Techniques in Cloud Computing (클라우드 컴퓨팅에서 적응적 VM 마이그레이션 기법 개발)

  • Lee, HwaMin
    • KIPS Transactions on Computer and Communication Systems
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    • v.4 no.9
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    • pp.315-320
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    • 2015
  • In cloud computing, server virtualization supports one or more virtual machines loaded on multiple operating systems on a single physical host server. Migration of a VM is moving the VM running on a source host to another physical machine called target host. A VM live migration is essential to support task performance optimization, energy efficiency and energy saving, fault tolerance and load balancing. In this paper, we propose open source based adaptive VM live migration technique. For this, we design VM monitoring module to decide VM live migration and open source based full-virtualization hypervisor.

Petunia Asteroid Mosaic Virus Isolated from Petunia hybrida Vilm. (폐츄니아에서 분리한 Petunia Asteroid Mosaic Virus)

  • 노궤미;최충원;최장경
    • Korean Journal Plant Pathology
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    • v.11 no.4
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    • pp.361-366
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    • 1995
  • A virus was isolated from petunia (Petunia hybrida Vilm.) plants showing chlorotic ring spots on the leaves and color breaking on the flowers, and was identified as petunia asteroid mosaic virus (PAMV). Identification of the PAMV was established by host range test, electron microscopy, serological reaction, and physical properties of the virus. In the host range test, Nicotiana glutinosa, N. rustica, N. clevelandii, P. hybrida, Gomphrena globosa, and Chenopodium amaranticolor were systemically infected with the virus. The virus produced local lesions on inoculated leaves of N. tabacum‘Samsun’, N. tabacum‘Xanthi nc’, Datura stramonium, Vigna unguiculata‘White eye’, C. quinoa, Capsicum annuum, Vicia faba, and Lycopersicon esculentum‘Rutgers’. However, Cucurbita sativus and C. moschata did not show any symptoms. PAMV particles were isometric with 30 nm in diameter. The crude sap from G. globosa infected with the virus reacted positively with antiserum to tomato bushy stunt virus (TBSV) in agar gel double diffusion test. Thermal inactivation point of the virus was 8$0^{\circ}C$ and the virus retained its infectivity at the dilution of 10-4. Longevity in vitro of the virus was estimated longer than 35 days.

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Relation between Black Hole Mass and Bulge in Hard X-ray selected Type 1 AGNs

  • Son, Suyeon;Kim, Minjin;Barth, Aaron J.;Ho, Luis C.
    • The Bulletin of The Korean Astronomical Society
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    • v.45 no.1
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    • pp.62.1-62.1
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    • 2020
  • We present a scaling relation between black hole (BH) mass and bulge luminosity for 35 nearby (z<0.1) type 1 active galaxies, selected from the 70-month Swift-BAT X-ray source catalog. Thanks to the unbiased selection and proximity of the parent sample, our sample is suitable to study the physical connection between central black holes and host galaxies. We use the F814W images obtained with the Advanced Camera for Surveys on Hubble Space Telescope, to perform the imaging decomposition with GALFIT. With a careful treatment on the PSF model, we measure the I-band bulge brightness robustly. In combination with the BH mass estimated from a single-epoch spectroscopic data, we present the correlation between BH mass and bulge luminosity of the target AGNs. We demonstrate that our sample marginally lies off from the M(BH)-L(bulge) relation of inactive galaxies. We discuss possible physical origins of this discrepancy. Finally, we present how the relation depends on the photometric properties of AGNs and host galaxies, which may provide an useful insight on the co-evolution between BHs and host galaxies.

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Microbial etiology of endodontic treatment failure

  • Kum, Kee-Yeon
    • Proceedings of the KACD Conference
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    • 2003.11a
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    • pp.606-606
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    • 2003
  • There have been many studies that have evaluated success and failure of endodontic treatment (Nair, Sjogren), but there is remarkably limited information concerning the specific microorganisms that are involved in the teeth with treatment failure. Microorganisms that survive root canal treatment to cause a persistent infection must possess specific characteristics to avoid the host defense. These can be broadly classified as; 1. Sequestration:A physical barrier between the microbe and the host. 2. Cellular evasion:Microorganisms avoid leukocyte dependent antibacterial mechanisms. 3. Humoral evasion:Extracellular bacteria avoid the hosts antibodies and complement.(omitted)

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