1. Effective Synchronization of Mobile Cloud Computing
SCHOOL OF INFORMATION SCIENCE
DEPARTMENT OF APLLIED INFORMATICS
Dissertation of : Tsoraklidou Georgia
Supervisor: Psannis Konstantinos

2. Summary presentation Purpose Meaning of Mobile Cloud Computing
Existing Research
Synchronization (meaning)
File Hosting Service (meaning)
Synchronization techniques
Comparison
Our proposal
Future work
References

3. 1) Purpose
Explain why the mobile cloud computing is necessary and important.
Research and analysis of existing technical synchronization
Proposal for a more efficient synchronization technique

4. 2) Mobile Cloud Computing
MCC is the combination of cloud computing, mobile computing and wireless networks to bring rich computational resources to mobile users, network operators, as well as cloud computing providers. MCC leverages unified elastic resources of varied clouds and network technologies toward unrestricted functionality, storage, and mobility to serve a multitude of mobile devices anywhere, anytime through the channel of Ethernet or Internet regardless of heterogeneous environments and platforms based on the pay-as-you-use principle.

5. 3) Existing research Advantages How it works Architecture Παροχές
Ορισμούς και δυνατότητες
Issues of mobile multimedia database systems

6. 4) Synchronization
Data synchronization is the process of establishing consistency among data from a source to a target data storage and vice versa and the continuous harmonization of the data over time. It is fundamental to a wide variety of applications, including file synchronization and mobile device synchronization. File Synchronization (or syncing) is the process of ensuring that files in two or more locations are updated by certain rules. one-way file synchronization, also called mirroring two-way file synchronization

7. 5) File hosting service
A file hosting service or cloud storage service, is an Internet hosting service specifically designed to host user files. It allows users to upload files that could then be accessed over the internet from a different computer, tablet, smart phone or other networked device, by the same user or possibly by other users, after a password or other authentication is provided. File hosting services often offer file sync and sharing services.
Known Services
Google drive
OneDrive
Dropbox
iCloud
115 SyncDisk
sugarSync
Amazon CloudDrive
SkyDrive

8. 6) Synchronization techniques (1)
rSync
used to synchronize files and directories between two different systems
requires the specification of a source and of a destination; either of them may be remote, but not both.
As a utility, it is not automated and only executes the synchronization when invoked
Update detection is done by checking the modification time and size of a file name by default
The md5 algorithm is used by rsync to determine which parts of a file have changed

9. 6) Synchronization techniques (2)
It completes the mirroring using only one round-trip, regardless of the number of files, minimizing the effect of high network latency. It is unable to detect renames, moves, and when using the default detection method, it is possible to miss some special cases, where a file is modified without changing its size

10. 6) Synchronization techniques (3)
UFS
Once a data update happens, the full content of the updated file f is delivered to the cloud.
Sync delay
Sync process simple
Sync traffic  proportional to the size of f
(sync traffic is proportional to the size of f rather than the size of the data update)
UFS is fit for instant file addition, rather than file modification or incremental file addition.
115 SyncDisk, UbuntuOne, Kanbox, Kuaipan, VDisk, and Wuala
Minimized when f = small
Long when f = small

11. 6) Synchronization techniques (4)
TFS
Once a data update happens, a timer is set to watch whether there will be following data updates in the subsequent T seconds.
Sync traffic  minimized
Sync delay  prolonged
Fit for specific frequent incremental file addition.
GoogleDrive , SkyDrive and Baidu CloudDisk
ΝΑΙ
ΟΧΙ
the full updated file is delivered to the cloud
this data update will be ignored

12. 6) Synchronization techniques (5)
UDS
Once a data update happens, only the latest data update(s) are delivered to the cloud.
Faster, safer and more reliable syncing
Sync traffic  significantly reduced
Sync delay  shortened
Complex mechanism due to the fact that it uses delta sync mechanism.
Fit for infrequent incremental file modifications.
Dropbox, IDriveSync, 360 CloudDisk and Everbox

13. 6) Synchronization techniques (6)
TDS
TDS is similar to TFS except that only data updates are delivered to the cloud.
Sync traffic
when the updated file is large but the “delta” file is small
Sync delay
More complicated than both TFS and UDS.
Fit for specific frequent incremental file modification.
SugarSync

14. 6) Synchronization techniques (7)
MPS
The updated file or data updates are delivered to the cloud only when the cloud sync process is manually or periodically performed.
If equipped with delta sync, MPS should be the most traffic-saving way to use a cloud sync service.
Inconvenient for data sharing among multiple users.
Fit for those situations that do not care about sync delay.
Easy to implement.
Amazon CloudDrive, Box , IDrive, SpiderOak, CrashPlan, Evernote, Youdao Cloud Note, CloudMe, QQ Cloud Disk and DBank

15. 6) Synchronization techniques (8)
Mechanism
App situations
App scenarios
MPS
Sync delay
tolerant situations
⓪ File backup
UFS
Instant file addition ⓪
①Picture/music/ immutable file storing or sharing
TFS
Specific frequent incremental file addition ⓪①
②File downloading (partially)
UDS
Infrequent incremental file modification
③Document editing
④System log append
TDS
Specific frequent incremental file modification
⓪①②③④
⑤Database updating (partially)
⑥Sensor network data collecting (partially)

16. 7) Comparison (1) Mechanisms Variables UFS 4 3 2 TFS 5 UDS TDS 1 MPS
Sync traffic
Sync delay
Design granularity
Level of complexity
UFS 4 3 2
TFS 5
UDS
TDS 1
MPS
Sync traffic: 1: the lowest, 5: the highest
Sync delay: 1: the shortest, 5: the longest
Design granularity: 1: fine-grained, 3: coarse-grained
Level of Complexity: 1: simple, 5: complex

17. 7) Comparing (2)

18. 8) Our proposal Combination of TDS and MPS - Why?
- Because if we combine specific functions and features of these two, then we may have a more effective sync mechanism.
Use of delta-sync mechanism which uses the rsync algorithm.
The location of changes in the file is important.  accomplished by rsync algorithm
Use a timer to control the updates  stabilization of sync traffic
Try to set the timer, so as if in Ti seconds have already happened U updates, then the last update is immediately delivered to the cloud, and the timer starts over again  stabilization of sync delay

19. 9) Future work
Examine in greater detail the synchronization mechanisms.
Try to give a better solution to the problem of efficient synchronization in motion.
Try to actually implement the proposed mechanism

20. 10) Πηγές και Βιβλιογραφία
[1] Box.com, [2] Dropbox, [3] Amazon CloudDrive, [4] Evernote, [5] Google Drive, [6] [7] Zhenhua Li, Zhi-Li Zhang, and Yafei Dai, Coarse-Grained Cloud Synchronization Mechanism Design May Lead to Severe Traffic Overuse, 2013 [8] Reza Shiftehfar, Kirill Mechitov, Gul Agha, Towards a Flexible Fine-Grained Access Control System for Modern Cloud Applications,2014 [9] Atta ur Rehman Khan, Mazliza Othman, Sajjad Ahmad Madani, Samee Ullah Khan, A Survey of Mobile Cloud Computing Application Models,2013 [10] Giwon Lee, Haneul Ko, Sangheon Pack, Chul-Hee Kang, Efficient delta synchronization algorithm in mobile cloud networks, 2014 [11] [12] Amitava Mukherjee, Somprakash Bandyopadhyay, Debashis Saha, Location Management and routing in mobile wireless networks, Artech House Publishers,2003 [13] Aftab Ahmad, Wireless and mobile data networks, Wiley-Intercience, 2005

21. Τhank you for your attention!!