A SOAP-oriented component-based framework supporting device ...

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14 Δεκ 2013 (πριν από 3 χρόνια και 10 μήνες)

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A SOAP-Oriented Component-Based Framework
Supporting Device-Independent Multimedia Web Services



Jia Zhang Jen-Yao Chung

infiNET Solutions IBM T. J. Watson Research
Buffalo Grove, IL 60089 Yorktown Heights, New York 10598
jiazhangchicago@yahoo.com jychung@us.ibm.com


Abstract

A web service is a programmable web application
accessible using standard Internet protocols. A three-
layer architecture has been suggested for web services:
service providers, service brokers, and service requesters.
We propose in this paper a SOAP-oriented component-
based framework to support device-independent
multimedia web services. Two intelligent agents are
introduced and embedded into proxy server and service
provider server, respectively. Separating metadata from
multimedia content leads to enhance SOAP flexibility.
Composite Capability/ Preference Profiles-based user
profile management provides an easy and flexible way to
split and adapt multimedia services to appropriate
composite devices as well as increases the flexibility for
users to manage multi-devices. Together with XML/XSL
strategy, we ensure the device independency of the
system. Utilizing local caches, our agents enable the
caching and streaming of multimedia transportation. In
addition, our framework seamlessly incorporates cutting-
edge technologies relating to web services: SOAP,
XML/XSL, and CC/PP.

Keywords
web services, SOAP, multimedia, framework,
XML/XSL, profile

1. Introduction

In the broadest sense, a web service is a programmable
web application accessible using standard Internet
protocols [15,20]. Roy [14] summarized a three-layer
architecture for web services: service providers, service
brokers, and service requesters. Service providers register
web services on service brokers; service brokers publish
registered services; service requesters fetch web services
from service brokers. As a consequence, the interface of a
web service should be strictly defined in terms of the
messages the web service accepts and generates [20].
Serving for web services, Simple Object Access Protocol
(SOAP) [16] is becoming a de facto standard. SOAP is a
lightweight protocol for exchanging structured and typed
information [1,17]. There are four major categories in
SOAP definition: defining the way of using eXtensible
Markup Language (XML) [8] to represent data, an
extensible message format, how to represent remote
procedure calls (RPC) using SOAP message format, and
bindings to Hypertext Transfer Protocol (HTTP) [14].
SOAP takes a major step to gravitate software
applications toward web and XML. In addition, due to the
fact of the advancement of wireless information
appliances, a web service will gain more popularity if it is
accessible to mobile devices, such as wireless phones and
Personal Digital Assistance (PDAs) as well as normal
web browsers [11]. Meanwhile, if the same set of
information can be delivered to different devices, the
system is called to have device independence [4].
However, most sites provide separate applications for
different devices [6] hence reusability and maintenance
among those different applications remain a problem.
Multimedia-oriented web services generally involve
transportation of multimedia contents over the web, and
management of composite devices for multimedia
contents. Multimedia content here implies the content that
seamlessly integrates multiple media types in a
synchronized and interactive presentation [10]. Caching
and streaming are major factors influencing the success of
deployment of Internet multimedia services [12]. Without
caching a server may experience implosion when it is
unable to keep up with an incoming stream of messages
[13,21], while every user tries to fetch multimedia
information from the server for every request. Caching
strategy utilizes a general web caching normally through a
proxy server [12]. Streaming paradigm implies that a
media file is played out when it is being received over the
web [12]. To manage the composite devices for users,
Composite Capability/Preference Profiles (CC/PP) [2]
specifies an XML and RDF based framework to help
define device capabilities and user preferences. It
provides a machine understandable and interoperable
basis for managing profile metadata [17].
There have been decent amount of research activities
in the area of web services. Hitherto, however, all existing
efforts address only specific aspects of web services. An
additional limitation is that those methods may or may not
integrate easily with most current web technologies. Our
Proceedings of the IEEE Fourth International Symposium on Multimedia Software Engineering (MSE’02)
2002114351/02 $17.00 © 2002 IEEE


research objective is to define a comprehensive
infrastructure to support multimedia web services. Here
we define a SOAP-oriented component-based framework
to support device-independent multimedia web services.
We accomplish our goal in several ways. First, two
intelligent agents are introduced and embedded into proxy
server and service broker server respectively. Second,
separating metadata from multimedia content leads to
enhance SOAP flexibility. Third, CC/PP-based user
profile management together with our enhancement
provide an easy and flexible way to split and adapt
multimedia services to appropriate composite devices, as
well as increases the flexibility for users to manage multi-
devices. Utilizing XML/XSL strategy, we ensure the
device independency of the system. Fourth, Utilizing
local caches, our agents enable the caching and streaming
of multimedia transportation. Finally, our framework
seamlessly incorporates cutting-edge technologies relating
to web services, such as SOAP, XML/XSL, and CC/PP.
The rest of this paper is organized as follows. In
Section 2, we discuss related work in web services. In
Section 3, we discuss the enhancement of SOAP protocol
for multimedia content. In Section 4, we introduce an
infrastructure for multimedia web services. In Section 5,
we present an experimenting system. In Section 6, we
summarize the contributions and innovations, assess
limitations and discuss future work directions.

2. Related work

In IDDS [10] system, hyperlinks are embedded into
HTML files pointing to original multimedia files such as
images, audio- and movie-clips. On the screen, the
corresponding multimedia information is displayed as
thumbnails or icons. The including multimedia pieces and
the HTML files might be stored separately in database.
Swan [18] encodes multimedia flow as layered signals
that are striped across different multicast groups. Vin [19]
built a three-layer model for multimedia collaboration:
streams layer, sessions layer, and conferences layer.
Streams layer manages media communication modulated
by access rights; sessions layer represents collections of
semantically related media streams; and conferences layer
represents temporally related sequences of sessions.
Paknikar et al [12] defines a client-side framework to
converge caching and streaming Internet multimedia. The
architecture consists of a number of caching proxy
servers. A central controlling proxy server called broker
handles all the initial interactions, and then may transfer
control to its sibling servers. The work also defines a
layered replacement policy for cashing scalably encoded
video objects. Paknikar predicted that Real Time
Streaming Protocol (RTSP) would become the de facto
standard for Internet A/V caching and streaming.
Pham et al. [11] defines a Small Screen/Composite
Device (SS/CD) architecture that implements small screen
device focused communication systems. The key
component of the architecture is a Smart Gateway (SG)
that outsources multimedia information to the most
appropriate composite devices to ensure reliable
performances, in which a critical part is relative
algorithms with a Selection-Device-Assignment-Matrix.
However, the work does not involve most current
standards and technology. FieldWise [3] relies on a server
engine to adapt responses to the capabilities of the client
devices and their network connections. Composite
Capability/Preference Profiles (CC/PP) [2] was designed
to register user preferences and device capabilities.
Koskelainen et al. utilizes the mechanism of carrying
remote procedure call (RPC) of SOAP to implement
commands for conference control system [7]. WebSplitter
[4] provides a unified XML framework for multi-device
web browsing. The framework defines an XML-based
metadata policy file based on CC/PP to enable users to
define access privilege groups. With the framework, all
web pages are constructed as XML files, with tags
specifying mappings to access privileges. A proxy is then
adopted to split a web page to different devices.
Corresponding XSL style sheets are attached to devices to
transform the customized XML to suitable device-
understandable languages. MyXML [6] is an XML/XSL
based template engine to solve the issue of device
independence. The idea is to completely separate content
from layout information [5]. However, MyXML
introduces a whole set of syntax elements that requires
learning curve. JBSL [9] introduces an abstraction layer
between presentation and application logic. By
dynamically generating user interface “snapshots” and
transforming generated description through XSL
processor, JBSL provides a framework for mobile
devices. Both MyXML and JBSL try to use XML/XSL
combination to realize device independence, as the similar
work in WebSplitter.
As described in the literature review decent amount of
research efforts have been conducted in the area of web
services. It appears that all existing efforts address only
specific aspects of development of web services. An
additional limitation is that those methods may or may not
integrate easily with current web technologies. Here we
seek to provide efficient support for multimedia web
services. In contrast with previous approaches, we
accomplish this objective by providing a SOAP-oriented
component-based framework to support device-
independent multimedia web services.

3. Enhancement of SOAP for multimedia
web services

SOAP is on the way to be the de facto standard for
web services. For simplicity, it does not support
boxcarring and batching of messages, as well as it is a
Proceedings of the IEEE Fourth International Symposium on Multimedia Software Engineering (MSE’02)
2002114351/02 $17.00 © 2002 IEEE


<SOAP-ENV:Envelope
….
SOAP-ENV:mustSendBack=”RequestId0001,
Profile001”/>
….
</SOAP-ENV:Envelope>

<SOAP-ENV:Envelope
….
SOAP-ENV:mustSendBack=”RequestId0001, Profile001”
SOAP-ENV:id=”Msg00001”
SOAP-ENV:index=”1”
SOAP-ENV:total=”5”/>
<SOAP-ENV:Body>
<m:Metadata>
<component>Msg00001”</component>
<component>Msg00002”</component>
<component>Msg00003”</component>
<component>Msg00004”</component>
<component>Msg00005”</component>
</m:Metadata>
</SOAP-ENV:Body>
….
</SOAP-ENV:Envelope>

Figure 1. Pieces of SOAP messages
one-way protocol [16]. If we consider using SOAP to
deliver multimedia web services, however, there are some
enhancements seem necessary. For example, it is difficult
to embed a large multimedia file into one SOAP message.
On the contrary, it may be more practical to load a big
chunk of information into multiple SOAP messages, with
the first message declaring the metadata information.
There should also be a way to identify the relationships
among those related SOAP messages. In exceptional
cases, some of the media files may not be even suitable to
be transferred in SOAP messages. Therefore, special
attributes should be provided to identify all of the above
situations. Here we suggest several enhancements as
follows.
We propose a simple workaround of boxcarring and
batching of messages for multimedia web services, which
introduce several global attributes. Simulating SOAP
envelope following real envelope in the real life, we insert
into SOAP envelope the information of the sender as the
first part. SenderURL is defined to specify sender URL; id
is defined to uniquely identify the message; index is
defined to identify the index of the message in the whole
message box; total is defined to identify the total number
of messages in the box. In addition, we introduce a global
attribute MustSendBack. Users can use this attribute to
contain information that needs to be sent back without
any changes. In addition, we propose to always have the
first message contains metadata in the body block, which
identifies the structure of the complete SOAP response
messages. Figure 1 illustrates example pieces of SOAP
messages showing the usages of our new terms. The first
example is a piece of SOAP request that contains request
id “RequestId0001”, which must be sent back. The second
example is a piece of SOAP response. We can see that the
message is the first of total five messages. Metadata
shows the message ids of the other four messages.

4. Proposed infrastructure supporting
multimedia web services

As Roy [14] summarized, web services extensively
adopt a three-layer architecture: service providers, service
brokers, and service requesters. In this paper we do not
discuss issues about service brokers, since they are to
certain degree yellow pages for corresponding service
ServiceRequester 1



Figure 2. Proposed MWS infrastructure

Web Service Provider

SOAP
message

SOAP
message

Internet

MM Device
MM Device

ServiceRequester 2


MWSAgent
Proxy Server
Proceedings of the IEEE Fourth International Symposium on Multimedia Software Engineering (MSE’02)
2002114351/02 $17.00 © 2002 IEEE


providers. In addition, service requesters eventually need
to connect to service providers to get the requesting
services. We make one assumption that, with the help of
service brokers, service requesters have already located
the service providers that offer the requested services.
Meanwhile, since high-speed local area networks (LANs)
have been deployed extensively over the world [12], users
on such LANs normally access Internet through a proxy
server that provides caching facility. Therefore, we make
another assumption on such a concept that users invoke
web services through their proxy server. We propose an
infrastructure supporting multimedia web services
(MWS) illustrated in Figure 2. Two intelligent agents are
introduced. One is Multimedia Web Service Server Agent
(MWSSAgent) that locates at service provider. The other
is Multimedia Web Service Agent (MWSAgent) that
locates at proxy server on the clients’ LAN. Proxy server
therefore becomes an intermediary between service
requesters and service providers. In addition, our
infrastructure is SOAP-oriented. We believe that our work
provides a powerful SOAP-based infrastructure to support
multimedia web services.
As shown in Figure 2, two service requester machines
locating on the same LAN try to access the same web
service through their common proxy server. MWSAgent
handles the requests, generates the final SOAP message
and sends to the service provider through web.
MWSSAgent on service provider helps generate the
return SOAP message(s) and sends them back to the
proxy server. MWSAgent then parses the return messages
and decides how to send the multimedia contents to
appropriate media devices, such as web browser, audio
system, PDA, etc. MWSAgent also tries to hit the
requested service in its local cache before connecting to
service providers. In this paper, cache is used to imply
local storage, therefore it can be either local disk or cache
in the memory. We will discuss each of the two agents in
detail in the following sections.

4.1 Multimedia Web Services Server Agent
(MWSSAgent)

A multimedia web service may generate a complex
result including multiple multimedia files. Disregarding
the fact that SOAP currently can only bind to HTTP while
HTTP was not designed for streaming media data [12], it
is not efficient and practical to include all information in
one SOAP response message to send back to requesters.
Therefore, we choose to completely separate metadata
from real content. The metadata includes the structure of
the set of messages, and links to other media files. The
information may be separated in multiple SOAP
messages, with the first message containing metadata and
specifying the identifications of other messages. The
response philosophy MWSSAgent adopts is a lazy-driven
norm. That is, it does not always send back all of the
messages at the same time; some messages may stay on
service provider until requested particularly.
We propose MWSSAgent as an intelligent agent on the
service provider site to facilitate multimedia services. Its
architecture is illustrated in Figure 3, together with the
interactions among its components. The infrastructure
contains three functional components - SOAP message
parser (MP), SOAP message generator (MG), SOAP
message manager (MM) - and a local cache. MP is in
charge of parsing incoming SOAP request messages,
figuring out the request and sending to MM. MM will
first check the cache to see whether the result SOAP
messages have already been generated and stored. If the
results exist, MM will send back the results through MG –
MG needs to generate corresponding return envelopes
based on the requests. If not, MM will invoke service
backend for the service. MG will then generate the full set
of SOAP response messages and store to the local cache,
and then send back the first response message including
metadata.
All of the SOAP response messages will be cached on
local disk under control of MM. This caching is
important, since published web service providers
normally expect large amount of requests. When a SOAP
request message comes in, MP will verify whether the
request is the first request for a service, or a successive
request for other response messages of a particular
service. When MG generates the set of response
messages, all messages will be uniquely numbered for
identification. We adopt caching and streaming
algorithms introduced in [12].

4.2 Multimedia Web Services Agent
(MWSAgent)


SOAP Message
Manager(MM)

Cache
Web Service
Backend
SOAP Message
Parser(MP)
SOAP Message
Generator(MG)

Request Response

Figure 3. MWSSAgent architecture

MWSSAgent
Proceedings of the IEEE Fourth International Symposium on Multimedia Software Engineering (MSE’02)
2002114351/02 $17.00 © 2002 IEEE


We propose MWSAgent as an intelligent agent on the
proxy server at client site to support multimedia web
services. The component-based architecture is shown in
Figure 4. MWSAgent comprises of four functional
components: service broker, user profile manager, service
delivery manager, and multimedia manager. In addition,
there are three caches contained in MWSAgent: one for
user profiles; one for request-profile mapping; and one for
multimedia information. We will discuss each functional
component in detail in the following sections.

4.2.1 User Profile Manager (UPM). Every user can
create his profile on the basis of CC/PP format. This
profile declares the list of the user’s available resources
(devices) and preferences about how his resources will be
used. We chose this format on two reasons. One is that
CC/PP is built on top of XML technology. The other is
that CC/PP was designed particularly for describing
device capabilities and user preferences. However, we
found that CC/PP definition is too rigid for device
capabilities. For example, one device may be capable of
accepting one kind of media information with simple
transformation. Therefore we extend CC/PP by enabling
transformation description to be added to devices. With
this extension, CC/PP protocol becomes more powerful of
describing device capabilities.
User profile manager (UPM) registers user profiles and
stores them to user profiles cache. UPM assigns a unique
id to every profile, so that one user can have multiple
profiles for the purpose of different web services. When a
user requests a web service, he needs to specify which
profile he wishes to use to receive the service. Service
broker will assign a unique id to the request, and UPM
will store the pair (request id, profile id) in the cache of
request-profile mapping. When response comes in, UPM
will pick up the stored corresponding profile from the
SOAP
Generator
SOAP Parser


register personal
CC/PP profile
update profile

User Profile

Manager
User Profiles
Service
Delivery
Manager
Service
Manger
Request
Manager
Multimedia

Content
Manager
Multimedia
Adaptation
Manager
MManager
Cache
MWSAgent
request
reply
Figure 4
. MWSAgent architecture

Service Broker

Request-Profile
Mapping


<ccpp:component>
<rdf:Description rdf:about=” TerminalHardware” >
<rdf:type rdf:resource=” HardwarePlatform”/>
<DeviceName>Nokia-3360</DeviceName>
<screen>30X23mm</screen>
<display>101X52Pixels</display>
<PixelStretch>1.24</PixelStretch>
</rdf:Description>
</ccpp:component>

<ccpp:component>
<rdf:Description rdf:about=” Services” >
<rdf:type rdf:resource=” SupportedServices”/>
<rdf:li>HTML</rdf:li>
<rdf:transform>HTML2WML.xsl</rdf:transform>
</rdf:Description>
</ccpp:component>


Figure 5. A piece of user profile
profile cache. Anytime users can change their profiles,
add new profiles, or delete some profiles. The granularity
of the definition of profile depends on the power of
CC/PP and RDF vocabulary. In user’s profile, every
resource is declared as a separate item, such as a WAP
phone. Each item comprises of two parts. One is the
declaration of the hardware. The other one is the
declaration of the service, or more directly multimedia
resource files that the device can receive. Figure 5 is a
piece of a CC/PP profile for a WAP phone. As shown, the
declaration of this WAP phone contains two parts. The
first part defines its hardware equipment, such as the
device name, size of the screen, resolution, etc. The
second part defines its acceptable multimedia
information, such as image, text, WML, etc. It can be
noticed that HTML2WML algorithm will be used to
transform receiving HTML code to WML code for the
WAP phone. When SOAP response message comes in,
UPM will locate the corresponding profile from cache by
profile id.

4.2.2 Multimedia Manager (MManager). Multimedia
Manager (Mmanager) contains two sub-components:
Multimedia Content Manager (MCM) and Multimedia
Adaptation Manager (MAM). MCM manages the caching
of multimedia SOAP response messages on the local disk.
We adopt caching algorithm introduced in [12]. MAM
handles media adaptation if necessary, in order to achieve
device independence. In some cases when the destination
device is not capable of handling requested multimedia
contents, MAM may convert the media accordingly. In
some other cases, the destination device may announce to
be able to receive some media contents, however some
adaptations need to be done by MAM likewise. For
instance, a WAP phone could accept HTML code
however it needs to be transformed to WML code. MAM
accumulates media transformation algorithms, which we
realized using XML/XSL technologies. In accordance
with our extension to CC/PP, when a user specifies his
profile, he can stipulate the transformation algorithm he
prefers.

4.2.3 Service broker. Service broker consists of four sub-
components: request manager, service manager, SOAP
generator, and SOAP parser, as shown in Figure 4. SOAP
generator helps generate SOAP request messages. SOAP
parser helps parse incoming SOAP response messages.
Request manager is a request broker of user requests for
web services. A user may request a web service when
another user from the same LAN has requested the same
web service already. Therefore, request manager will first
check the local disk through MCM. If result is hit, request
manager will pass the control to service manager to send
back the information. Otherwise, request manager will
assign a unique id to the request, ask UPM to store to
request-profile mapping, and then call SOAP generator to
generate SOAP request message and send to the service
provider over Internet. As a consequence, not only the
remote service broker and service provider will have less
traffic, but also the response time may be largely
shortened. Service manager is invoked when a SOAP
response comes back from Internet. It will first call SOAP
parser to analyze the content of the result message. If the
result contains multimedia information not coming
together with the first message, service manager will
schedule to prefetch the corresponding media files to
enhance the streaming of the media data. All the messages
will be sent to MCM to store in local disk before sending
back to user, to achieve caching. The source might not be
even on-line all the time but its content can always be
available at the cache of MWSAgent. Considering
scalably encoded or layered video information, for
example, such objects have a “base” layer containing
essential information, and one or more “enhanced” layers
containing higher level information [12]. Service manager
will try to download the sub-nodes following the layers. It
will try to download the lower layers before downloading
higher and more enhanced layers. Meanwhile, service
manager will work with UPM to launch the corresponding
user profile. And then the control will be passed to SDM
to deliver the result to the user.

4.2.4 Service Delivery Manager (SDM). Service
delivery manager (SDM) decides the priority and order of
the services to be sent back to the users, and decides how
to split return information to appropriate devices, as
shown in Figure 6. It is important to avoid the
performance of a current multiple service requests. A set
of criteria is kept at SDM to be used to optimize the order
of the delivery. Since all the information is stored in
XML-based SOAP messages, SDM explores tags
contained in the objects. Only media resource tags are
considered and all its attributes are examined. Attributes
Proceedings of the IEEE Fourth International Symposium on Multimedia Software Engineering (MSE’02)
2002114351/02 $17.00 © 2002 IEEE



Figure 7. Snapshot of distance learning system

can give detailed information about the multimedia
object, such as size, resolution, constraints, and format,
etc. A media resource can be delivered to a user if the
user has one device that accepts corresponding media
resource.
























5. Example

To prove the effectiveness and efficiency of our
framework serving for multimedia web services, we
constructed an experimental system, which is a distance-
learning environment. Figure 7 is a snapshot of the
system. One server machine stores course information and
serves as service provider. Two students request courses
from this server machine as service requesters. The first
student possesses one computer and speakers, while the
second student has a cell phone and speakers. Both
students reside on the same LAN and send out requests
through a proxy server machine. We installed
MWSSAgent on the server, and MWSAgent on proxy
server. As we discussed earlier, we skip service broker
layer for simplicity. The two students register their device
profiles through UPM on their proxy server. The courses
here include multimedia information. Let us consider a
scenario of using this system. Suppose the first student
specifies his profile and requests a multimedia course,
which contains video and audio chips together with text
and graphics information. MWSAgent does not find
corresponding course content from its local cache, so that
is assigns a unique id to the request and stores (request id,
profile id) pair in the local disk, and then generates SOAP
request message and sends to the server. MWSSAgent on
the server generates five SOAP messages, while the first
one includes metadata and the other four each comprises
of one media file respectively. Then MWSSAgent stores
all five messages on its local cache and sends back the
first message. MWSAgent on the proxy server receives
the SOAP response message, parses it and figures out that
it is the first of total five messages and contains metadata.
So that MWSAgent continues to contact with server to
fetch the left four multimedia files. From the SOAP
envelope, MWSAgent also picks up the (request id,
profile id) pair so that the corresponding profile can be
fetched from local disk. MWSAgent finds that the first
student has one computer and speakers. Therefore, it calls
SDM to send text, graphics and video information to the
computer and deliver audio chips to the speakers.
Suppose then the second student requests the same course
information. MWSAgent finds that the course information
has already been cached on its local disk. Therefore it
directly fetches the student’s profile, and decides to send
text information to the cell phone through transformation,
and send audio chips to the speakers. Both graphics and
video chips will be discarded.
















6. Assessments, innovations and future work

We propose in this paper a SOAP-oriented component-
based framework to support device-independent
multimedia web services. In the current infrastructure, we
adopt caching and replacement algorithms introduce in
[12] for both MWSAgent and MESSAgent. Since these
two agents serve for different purposes, using the same set
of caching and replacement algorithms may not be most
efficient. Despite of this limitation that can be resolved by
further work, our framework benefits multimedia web
services in several ways. Two intelligent agents are
introduced and embedded into proxy server and service
provider server respectively, to facilitate SOAP-oriented
multimedia web services. Separating metadata from
multimedia content leads to enhance SOAP flexibility.

Figure 6. SDM splits multimedia data

Proceedings of the IEEE Fourth International Symposium on Multimedia Software Engineering (MSE’02)
2002114351/02 $17.00 © 2002 IEEE


Introduction of several global attributes to the definition
of SOAP envelope enhances SOAP ability of serving for
multimedia services. CC/PP-based user profile
management together with enhancement of CC/PP
specification provides an easy and flexible way to split
and adapt multimedia services to appropriate composite
devices as well as increases the flexibility for users to
manage multi-devices. Together with XML/XSL strategy,
we ensure the device independency of the system.
Utilizing local caches, our agents enable the caching and
streaming of multimedia transportation. In addition, our
framework seamlessly incorporates cutting-edge
technologies relating to web services: SOAP, XML/XSL,
and CC/PP.
Our future work includes exploring efficient caching
and replacement algorithms for agents on proxy server
and service provider respectively. We would also try to
bind SOAP to other more multimedia-oriented
transportation protocols, such as Real Time Streaming
Protocol (RTSP). Finally, we would like to pursue code
generation on the two intelligent agents.

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