Quality of Service in Video Databases

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Quality of Service in Video Databases

• Mohand-Saïd Hacid
• Joint work with
• Elisa Bertino (Univ. Milano-Italy)
• Tiziana Catarci (Univ. Roma-Italy)
• Ahmed K. Elmagarmid (HP-USA)

MSI Project (Multimedia System Infrastructure
Funded by NSF)
To develop an infrastructure that will integrate
key information technologies which include
database and storage management, knowledge
representation, networking, and security in
order to support a comprehensive end-to-end QoS
management framework for video database
applications
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DBMS
OLTP
MIS/DSS
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Security
-Access control
Negotiation
Dependency Model Analysis and QoS Adjustement
End-to-End Run Time Management
End-to-End Resource Allocation and Scheduling
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Overview

• Introduction
• About QoS
• A Framework for QoS Management in
• Video Databases
• Conclusion

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Introduction

• Video an important and rich vehicle of
• information
• gt Home movies
• gt Education and training
• gt Scholarly research
• gt Corporate enterprise solution
• gt Urban security
• ...

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Introduction (Cond.)

• Emergent Applications
• gt Multimedia databases
• gt Monitoring
• gt (Distributed) simulation
• gt Virtual reality, video games, virtual cinema
• gt Decision support
• gt Video conferencing
• gt Internet video
• Though only a partial list, these
• advanced applications need new
• techniques and tools for managing
• video data

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Introduction (Cond.)

• Video ? Complex media
• gt Large volumes of data
• Example
• INA has more than
• - 1.500.000 long-length visual documents
• - 630.000 news documents
• - 1.000.000 medium-length visual documents
• gt Time-based media
• Semantics (granularity)
• Presentation
• How to organize and search the data?

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Introduction (Cond.)
Semantics
Annotations
Clusters
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Introduction (Cond.)
Presentation
Interface level
- Synchronization - Distribution
? Prediction
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Quality of Service
Mouvement, Video texturing, Word structure
Interface level
PC Terminal
Users parameters presentation, etc.
Video medium level
Level of services Video QoS parameters
frame-rate, resolution,
Network and OS level
Network and OS QoS parameters Bandwidth, CPU
time, end-to-end delay,
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Quality of Service

• Problems
• gt Specification of the requirements
• gt Management/Support of the requirements
• gt Need to investigate specific functionalities
• ? Service Quality Management

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Quality of Service

• Quality of Service (QoS) is defined as a set of
• perceivable attributes expressed in a
  user-friendly
• language with parameters that may be subjective
• or objective.
• - Objective parameters those related to a
• particular service and are measurable and
• verifiable.
• - Subjective parameters those based on the
  opinions of
• the end-users.

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Quality of Service

• As a consequence
• - the user specifies her/his requirements
  (constraints)
• - the system has to satisfy the requirements
• QoS is multidimensional
• - reliability, display time, resolution, price,
  ...
• Classes of QoS
• - QoS guarantee
• Yes for data application. But for
  multimedia applications
• the internet offers no guarantees about when
  (or even if) packets
• will be delivered and clients need not ask
  permission before
• transmitting packets.
• - Best-effort
• May deteriorate the global quality
• - Prediction-based, followed by resources
  reservation

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Quality of Service

• Tasks
• Specification
• gt QoS requiremnts are defined by users or
  applications
• gt Different dimensions and priorities
• Mapping
• It is regarded as the process of translating
  QoS-parameter bounds from layer to layer, and
  finally, to resources, e.g., buffers
• Negotiation
• Negotiation mechanisms (embedded in protocols)
  allow to ensure that the required parameters can
  be consistently satisfied at all system levels
• ?
• - admission control
• - resource allocation

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Quality of Service

• QoS Management
• Monitoring
• Comparison of the QoS level offered by the
  system and initial requirements notification in
  case of problems (system unable to sustain
  negotiated levels of QoS)
• Re-negotiation
• Changes due to users or systems components lead
  to re-negotiation
• ? need to go through specification and mapping
• Adaptation
• Necessary in the case of resource fluctuations

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DBMS and QoS

• DBMS is a fundamental component in large-scale
• distributed environments
• gt It can implement some tasks related to QoS
  management
• gt It can participate to decide QoS
• Two perpectives
• gt DBMS for QoS management
• ? Some QoS management tasks are delegated to
  the DBMS
• (mapping, resource reservation,
  ...).
• gt QoS management for DBMS
• ? QoS related to communication takes place in
  the
• evaluation of queries in parallel
  and distributed DB.

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DBMS for QoS

• How DBMS can take part in the management of QoS?
• gt the DBMS stores data and meta data for QoS
• - values of QoS parameters for
  documents
• (image and video quality, encoding
  format)
• - QoS-based alternatives
• (for negotiation)
• - information related to system
  management
• gt can execute QoS-based queries
• gt can execute queries with time-based or
  cost-based
• constraints

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DBMS for QoS
Traditional Databases
concerned with the delivery of correct results
with acceptable delay.
Video databases ? New challenge
to deliver results with acceptable quality in
real time
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DBMS for QoS
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DBMS for QoS
Query Processor
Insertion Module
Quality Manager
Interactive Video Processor
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DBMS for QoS

• Some tasks can be executed by the DBMS
• - some QoS dimensions can be transformed into
  search
• criteria
• - the priorities between QoS parameters used for
  classifying
• offers can serve as sorting criteria
• - sorting will help re-negotiation or adaptation
• Examples
• - retrieval of video data satisfying the search
  criteria
• specified in the query and having a version
  satisfying the QoS of the
• client machine. Sort the results according
  to the priorities defined in
• the QoS profile.
• - one can use relational views, query rewriting
  techniques and sort
• criteria

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DBMS for QoS

• QoS profiles
• - to allow a definition of the QoS parameters
• - to propose to users different predefined sets
  of QoS
• parameters by means of examples
• - to provide a high-level perception of QoS
  parameters
• - to create personalized and re-usable
  environments
• QoS manager
• - collect all QoS informations from the systems
  components
• - collect QoS specifications of the user
• - execute QoS negotiation

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QoS management for DBMS

• Traditional query optimization criteria
• - minimize response time by reducing the used
• resources
• Other optimization criteria are possible
• - search for the most recent information
• - minimize the cost to retrieve the information
• - retrieve the best quality (high-color video
  with 30
• images/seconde)

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DBMS for QoS

• QoS management can be seen as mechanisms
• to extend or restrict the search space for a DB
• query

Video database
Available offers
Negotiation with static parameters
BO
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Evaluation Elaboration
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Reasoning on QoS
video(X), audio(Y), X contains Z Z name
Clinton, X has_audio Y? display_time(td),
td?5, resolution(X, high)
?X/v, Y/a, Z/o
? video(v), audio(a), v contains o, o name
Clinton, v has_audio a
? display_time(td), td?5, resolution(X,
high)
With the elaboration rule
?.? ??.??synchronize(X, Y) if ?
contains video(X), audio(Y), X has_audio Y
we can derive synchronize(v, a)
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Reasoning on QoS (Cond.)
Now by using the elaboration rule
?.? ??.??tXstarttYstart, tXendtYend
if ? contains synchronize (X, Y) and tXstart,
tYstart are variables denoting starting times of
X and Y, respectively and tXend, tYend are
variables denoting ending times of X
and Y, respectively
we can derive the atomic constraints
tvstarttastart
and tvendtaend
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Reasoning on QoS (Cond.)
tv display time the video displayer can provide
from tvstart ta display time the audio player
can provide from tastart
?.? ??.??tXtd ?tXtv, tYtd?tYta
if ? contains synchronize (X, Y) and tv is the
display time the video displayer can provide from
tX and ta is the display time the audio player
can provide from tY tX and tY being the starting
time for displaying X and playing Y,
respectively
? display_time(td), td?5, resolution(v,
high), synchronize(v, a),
tvstarttastart, tvendtaend,
tvstarttd?tvstarttv, tastarttd?tastartta

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Conclusion
Quality management Configuration constraint
specification how to express constraints? how
do these constraints evolve in time? how do we
configure a consistent schedule? QoS-sensitive
real-time disk scheduling techniques for video
data! The problem of scheduling a set of tasks
with time and resource constraints
is NP-complete ?
Heuristics!! Approximation constraint
relaxation
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The PLP framework
First order theory
H?B1, , Bn (n?0) definite clauses H?C1, ,
Cl?B1,, Bm (l, m?0) optimization clauses
Arbiter
p(t)?p(u)?L1, , Ln (n?0)
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Performing Negotiation by Constraint Relaxation
P (?C, ?O,?)
with ?C reliability(very
high)?throughput(X), Xlt100, Xgt66,
reliability(high)?throughput(X), Xlt66
?O u-reliability(X)?reliability(X)
External function
?u-reliability(medium)?u-reliability(high)?.
, u-reliability(high)?u-reliability(very
high)?. u-reliability(medium)?u-reliabi
lity(very high)?.
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Consider a user query ??? whose quality part ?
contains the constraint u-reliability(medium
)
Suppose
reliability(very high)?throughput(X), Xlt100,
Xgt66
triggers
then
u-reliability(medium)?u-reliability(very
high)?.
can be applied
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Algorithm (??)
Require a query ??? (? is the
content part and ? is the quality part)
//? is the minimum QoS required by the
user Ensure evaluate ? by maintaining ?
satisfiable. 1 DisplaySet?? //computeQoS
computes new quality parameters ? from ? and the
system state //this means performing
negotiation which consists in
//computing the new qualifiers for the parameters
in ? //computeQoS stands for the
preference program of a quality manager 2
computeQoS(?, ?) 3 if ??? then 4 Have the
database to output the first answer x to ? 5
DisplaySet?DisplaySet?x //rewrite ? to exclude
the already displayed video sequences 6 rewrite
? as ?-DisplaySet 7 repeat 2 until no answer
satisfies ? 8 end if
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Implementation done by A. Rezgui (Univ. Purdue)