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Client-Side Journaling for Durable Shared Storage

Andromachi Hatzieleftheriou, Stergios V. Anastasiadis
2017 ACM Transactions on Storage  
of individual storage devices at the host. iv) Performance Client writes are safely stored at sequential disk throughput, but the read performance depends on the efficiency of the client memory cache. v)  ... 
doi:10.1145/3149372 fatcat:73fc3k76vfe6pcuhb4f7o2s2ta

Improving Bandwidth Efficiency for Consistent Multistream Storage

Andromachi Hatzieleftheriou, Stergios V. Anastasiadis
2013 ACM Transactions on Storage  
V. Anastasiadis (corresponding author), Department of Computer Science, University of Ioannina, Ioannina 45110, Greece; email: stergios@cs.uoi.gr.  ...  V. Anastasiadis Fig. 8. (a) With low rates, the write latency (lower is better) of ordered and writeback mode appears orders of magnitude longer than the other modes.  ... 
doi:10.1145/2435204.2435206 fatcat:f445e6qrwnh3nao4nz36ftlvly

Incremental Text Indexing for Fast Disk-Based Search

Giorgos Margaritis, Stergios V. Anastasiadis
2014 ACM Transactions on the Web  
ACM Reference Format: Giorgos Margaritis and Stergios V. Anastasiadis. 2014. Incremental text indexing for fast disk-based search.  ...  Table V .  ...  SRF combines low indexing time with list contiguity on disk [Margaritis and Anastasiadis 2009 ], but also has several shortcomings.  ... 
doi:10.1145/2560800 fatcat:bdwpapill5g6lawoih67ojljaa

Nephele: Scalable Access Control for Federated File Services

Giorgos Margaritis, Andromachi Hatzieleftheriou, Stergios V. Anastasiadis
2012 Journal of Grid Computing  
The integration of storage resources across different administrative domains can serve as building block for the development of efficient collaboration environments. In order to improve application portability across such environments, we target data sharing facilities that securely span multiple domains at the filesystem rather than the application level. We introduce the hypergroup as an heterogeneous two-layer construct, where the upper layer consists of administrative domains and the lower
more » ... ayer of users from each participating domain. We use public keys to uniquely identify users and domains, but rely on credentials to securely bind users and domains with hypergroups. Each domain is responsible for authenticating its local users across the federation, and employs access control lists to specify the rights of individual users and hypergroups over local storage resources. In comparison to existing systems, we show both analytically and experimentally reduced transfer cost of remote authorizations and improved scalability properties.
doi:10.1007/s10723-012-9217-4 fatcat:tuo53ytg6beplesdatd3s3kjaq

Lethe: Cluster-Based Indexing for Secure Multi-user Search

Eirini C. Micheli, Giorgos Margaritis, Stergios V. Anastasiadis
2014 2014 IEEE International Congress on Big Data  
'V ,QGH[ 1DPH 8VHU ,'V 'RF ,'V ,QGH[ ,' 6HDUFKHU ,'V 'RF ,'V 6HDUFKHUV &OXVWHU )DPLO\ TABLE I WE I SUMMARIZE THE DESCRIPTION OF SYMBOLS USED IN LETHE.  ...  In Sections IV and V we show our experimental results and examine previous related work, while in Section VI we summarize our conclusions and plans for future work. II.  ... 
doi:10.1109/bigdata.congress.2014.54 dblp:conf/bigdata/MicheliMA14 fatcat:r5mpmornrbdg3ltrvz2r2gvoiu

Parallel Application Scheduling on Networks of Workstations

Stergios V. Anastasiadis, Kenneth C. Sevcik
1997 Journal of Parallel and Distributed Computing  
A classification of scheduling policies that have been proposed for different parallel architectures up to now is given by Anastasiadis [1] .  ... 
doi:10.1006/jpdc.1997.1335 fatcat:o3oi7qg57zd2fftwp3vz762t6i

Host-side Filesystem Journaling for Durable Shared Storage

Andromachi Hatzieleftheriou, Stergios V. Anastasiadis
2015 USENIX Conference on File and Storage Technologies  
of individual storage devices at the host. iv) Performance Client writes are safely stored at sequential disk throughput, but the read performance depends on the efficiency of the client memory cache. v)  ... 
dblp:conf/fast/Hatzieleftheriou15 fatcat:l3p2boxp2jbprh4etk32vhrmoa

Efficient Multi-User Indexing for Secure Keyword Search

Eirini C. Micheli, Giorgos Margaritis, Stergios V. Anastasiadis
2014 International Conference on Extending Database Technology  
Secure keyword search in shared infrastructures prevents stored documents from leaking confidential information to unauthorized users. We assume that a shared index provides confidentiality if it can only be used by users authorized to search all the documents contained in the index. We introduce the Lethe indexing workflow to improve query and update e ciency in secure keyword search. Lethe clusters together documents with similar sets of authorized users, and only creates shared indices for
more » ... nfigurable volumes of documents with common users. Based on the published statistics of an existing dataset, we show that Lethe generates an indexing organization that simultaneously achieves both low search and update cost.
dblp:conf/edbt/MicheliMA14 fatcat:qwnuwhrmdzashbcdg4m5xbuqgu

Efficient Range-Based Storage Management for Scalable Datastores

Giorgos Margaritis, Stergios V. Anastasiadis
2014 IEEE Transactions on Parallel and Distributed Systems  
Stergios V. Anastasiadis is Assistant Professor in the Department of Computer Science and Engineering, University of Ioannina, Greece.  ...  := sizeof(b R )/F 7: Allocate v new rangefiles f (1) R , . . . , f (v) R on disk 8: Split b R into v subranges R (1) , . . . , R (v) of equal size 9: Transfer subranges to respective f (1) R , . . . ,  ... 
doi:10.1109/tpds.2013.305 fatcat:rhuktbxujvewbnhguko3y2mpy4

Estimation of HRV Based on Low Frequency Data Transmission

George Manis, Stergios V Anastasiadis
2020 Studies in Health Technology and Informatics  
Anastasiadis / Estimation of HRV Based on Low Frequency Data Transmission 257  ... 
doi:10.3233/shti200651 pmid:33087622 fatcat:w2jkwjiabrfchjidcc3wwsbate

Virtualization-aware access control for multitenant filesystems

Giorgos Kappes, Andromachi Hatzieleftheriou, Stergios V. Anastasiadis
2014 2014 30th Symposium on Mass Storage Systems and Technologies (MSST)  
V. SYSTEM PROTOTYPE Next we describe our implementation of the Dike multitenant access control over a distributed filesystem.  ...  Then we describe our system design ( §IV) and prototype implementation ( §V). We present our experimentation environment and explain some representative experimental results ( §VI).  ... 
doi:10.1109/msst.2014.6855543 dblp:conf/mss/KappesHA14 fatcat:xrqiiluxl5fw7onaql6flc5q6y

Scale and performance in semantic storage management of data grids

Stergios V. Anastasiadis, Syam Gadde, Jeffrey S. Chase
2005 International Journal on Digital Libraries  
For example, p 0 = v 0 returns one file, while p 9 = v 9 returns 512 files. In queries of two attributes, we use the conjunction p i+1 = v i+1 AN D p i = v i+1 .  ...  Subsequently, we attach ten attribute-value pairs, a 0 = v 0 , a 1 = v 1 , ..., a 9 = v 9 , to each file in a collection of 1024 files.  ... 
doi:10.1007/s00799-004-0086-8 fatcat:6snhtfcxn5ekzlrydksjuq5ddy

Server-based smoothing of variable bit-rate streams

Stergios V. Anastasiadis, Kenneth C. Sevcik, Michael Stumm
2001 Proceedings of the ninth ACM international conference on Multimedia - MULTIMEDIA '01  
b(t'dl"v)::= trn,, + 1 ,, trnd -1 Sb(t,,,) + B, end-for Sd(trnd) := Sd(trnd) -Bt &f until (tmln >= trnd) (*prefetch search failed*) &f end-for & The Server Smoothing algorithm generates majorization minimal  ... 
doi:10.1145/500141.500165 fatcat:fubnzfsmivdethriqct6jz6oqe

Server-based smoothing of variable bit-rate streams

Stergios V. Anastasiadis, Kenneth C. Sevcik, Michael Stumm
2001 Proceedings of the ninth ACM international conference on Multimedia - MULTIMEDIA '01  
b(t'dl"v)::= trn,, + 1 ,, trnd -1 Sb(t,,,) + B, end-for Sd(trnd) := Sd(trnd) -Bt &f until (tmln >= trnd) (*prefetch search failed*) &f end-for & The Server Smoothing algorithm generates majorization minimal  ... 
doi:10.1145/500164.500165 fatcat:mwr5fe5evzb2rhwpec6d5coaqa

Low-cost management of inverted files for online full-text search

Giorgos Margaritis, Stergios V. Anastasiadis
2009 Proceeding of the 18th ACM conference on Information and knowledge management - CIKM '09  
In dynamic environments with frequent content updates, we require online full-text search that scales to large data collections and achieves low search latency. Several recent methods that support fast incremental indexing of documents typically keep on disk multiple partial index structures that they continuously update as new documents are added. However, spreading indexing information across multiple locations on disk tends to considerably decrease the search responsiveness of the system. In
more » ... the present paper, we take a fresh look at the problem of online full-text search with consideration of the architectural features of modern systems. Selective Range Flush is a greedy method that we introduce to manage the index in the system by using fixed-size blocks to organize the data on disk and dynamically keep low the cost of data transfer between memory and disk. As we experimentally demonstrate with the Proteus prototype implementation that we developed, we retrieve indexing information at latency that matches the lowest achieved by existing methods. Additionally, we reduce the total building cost by 30% in comparison to methods with similar retrieval time.
doi:10.1145/1645953.1646012 dblp:conf/cikm/MargaritisA09 fatcat:qtyfmzdcvnawnm33ksxvsej7wm
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