Foundations of Mobile Agent Systems
Early discussions in this area argued that there are no MA applications, but rather
applications that benefit from the use of MAs [2], which has proven a sensible
statement after more than a decade of research into the subject. Similarly, MAs can
be regarded as the enabling technology for a networking application. In general,
security issues have proven to be the most discouraging factor toward a wider
Complexity Shared memory Message passing Remote procedure call (RPC)
Remote method invocation (RMI) Other mobile codes Mobile codes Mobile agents
FIG. 1. Data communications mechanisms. adoption of MA technology [3–5]. In other words, opening the doors to seemingly
benign, interpretable programs make networked devices susceptible to a number of
malicious attacks. As a result, cyprus company registration we observe that certain types of networks have
benefited more than others from implementing MA-based applications in real
systems. In general, closed networks provide a secure environment to deploy MA
technology and benefit from its unique features. Thus, not only the application type
but also the network environment plays an important role for deciding how an MAbased
solution should realize one or more tasks. Figure 2 illustrates the implementation
types that software agents stationary bike can take.
The most important characteristic of the MA approach and software agents in
general is that it allows programmability, thus enabling an MA-based system to
change its operation on demand to adapt the circumstances determined by the
underlying environment. For example, a network with sufficient bandwidth can
support the deployment of many MAs collaborating to achieve a number of tasks.
Nevertheless, a sudden bandwidth shortage as sensed by these agents could activate
a low-usage mode of operation, whereby only a few agents perform only the most
crucial tasks. It follows that the MAs’ policies can be either static or variable. By the
same token, the most important benefit pet supplies introduced by the mobility feature of a
software agent is that it enables better bandwidth usage by moving the processing
element to the location where the data to be analyzed resides. For example, moving a
500 KB program to process 100 MB of data at a remote location is more bandwidth
Multiple agents working together and applying preset actions Multiple agents working
together and adapting their operations as needed An agent whose decision policy may change in
response to the current environment conditions Multiple agents working independently on the
same task An agent that requires no external input and executes preset actions An autonomous agent that
adapts its decision policy as needed Adaptive Self-sufficient Collaborative Intelligent agents
FIG. 2. Implementation types of software agents. efficient than carrying out the reverse procedure. However, it is also clear that
implementing an efficient migration policy is crucial in achieving this bandwidthsaving
goal.
Thus far, we have pinpointed some key aspects that are relevant to deploying
MAs: flexibility to implement diverse applications, adaptability to deal with unforeseen
situations, efficient migration mechanisms funny t shirts to improve performance, an
application-dependent strategy, and preference for closed-network deployment. It
is straightforward to see that MAs are best suited for highly specialized applications
in access-restricted networks that are subject to unexpected, variable conditions, and
resource constraints. As a result, we turn our attention to exploring the applicability
of MAs to support diverse tasks in wireless and mobile networks. These types of
networks possess some or all the peculiarities just mentioned. In particular, we direct
the focus of our investigations to wireless sensor networks (WSN) and ad hoc
networks created by portable devices.
edmonton home builder However, to better understand the relevance
of investigating MA applicability in these networks, we present a concise discussion
on the advantages and disadvantages of MA technology, followed by a brief
historical perspective with concerning previous research efforts involving MA
technology, its shortcomings, the current state of affairs, and what we can expect
to see in the near future.
1.2 Advantages and Disadvantages of Using MAs
The benefits and drawbacks of the replica watches MA approach were extensively discussed in
the initial years of its research. In general, there are some advantages that are
attributable to all agent types, whereas others are more specific. For instance,
compactness is oftentimes loveseat referred to as an inherent MA characteristic, though
this is not always the case. For instance, an MA coded to perform a complex
brokering task requires that a significant amount of Essay writing functionality be implemented
into it to deal with a wide variety of possible situations for the transactions it
supports. However, MAs used for active networking tasks (e.g., routing) can be
significantly more compact because they are targeted at specific tasks with wellknown
outcomes. Another advantage regularly associated to using agents is bandwidth
savings, which can be achieved if an efficient agent migration policy is
employed. However, it is possible that the bandwidth overhead incurred by moving
a relatively large agent could offset the one incurred by using a simple messagepassing
scheme, depending on the application. Still, Atkins Diet Food List the bandwidth-savings potential
remains by far one of the most compelling reasons for using agents [6].
Figure 3 exemplifies the bandwidth savings-feature by showing both a traditional
and an MA-based approach for collecting data in a WSN. In the first case, the
occurrence of an event as sensed by individual WSN nodes initiates the
APPLICATIONS OF MOBILE AGENTS IN WIRELESS NETWORKS 117
corresponding client–server interactions to send raw data to the WSN gateway or
sink for subsequent analysis. In this approach, each client–server session incurs one
data flow from source to destination, leading to higher bandwidth utilization.
Moreover, this method places a higher burden in the nodes closer to the WSN
gateway because their links observe heavy data traffic as compared to the wireless
links located farther away from the gateway. Conversely, the mobile agent system
(MAS) approach dispatches an agent to the WSN’s region of interest (ROI) where
the event was observed. Once there, the MA processes data and sends back to the
WSN gateway either a concise assessment of the situation or a digest of the analyzed
data. This has the benefit of incurring Pizza Express vouchers a single traffic flow, in contrast to the client–
server approach that observes multiple flows.
In addition to enabling bandwidth savings, MAs can also help reduce processing
delay. Revisiting the example shown in Fig. 3, the actual data pooling process
triggered by an event in a WSN region might require multiple interactions between
the WSN gateway and the nodes involved. This obeys to the possibility of having a
relatively large amount of data that have to be progressively transferred if, say, the
first data block yields no conclusive no no hair removal results and one block or more need to be pooled
from the corresponding devices until a result is found. Conversely, in the MA
approach, the codes that actually process data migrate to the devices that triggered
the event, and the analysis is realized in situ, so that ergohuman no messages or data need to be
sent back and forth from the devices to the WSN gateway. In addition, if a result is
not found, the MA can migrate to another node to immediately begin analyzing more
data, whereas using the message-passing approach entails initiating a new session
between the WSN gateway and another device, win free ipad 2 followed by the respective data
Agent dispatched Mobile agent approach Agent migration Event path notification
Event region Gateway Raw-data flows A Data forwarding B approach.
transfer process. It is clear that the MA approach incurs less delay during its
migration process than consecutively forwarding raw data segments. Resilience is
yet another advantage that an MA-based solution can incorporate in environments
whose behavior is unstable or highly uncertain. For instance, whereas a messagepassing
scheme incurs significant signaling to recover from failures during an
ongoing data transfer session under adverse digital signage circumstances (e.g., in the presence of
a noisy-channel, or frequent disconnections), an Data Mining Software MA-based solution could have the
agent monitor the channel conditions until the circumstances are favorable to
migrate back to the WSN sink with the desired information.
The previous discussion provides some compelling reasons in favor of using MAs
to solve distinct networking tasks. In fact, it is easy to see that these advantages are
highly appealing for the case of wireless and mobile networks. However, there are
important counterarguments against MA technology. For instance, bandwidth savings
can only be achieved if the size of one or more MAs performing a task is
sufficiently compact to offset the bandwidth otherwise incurred by employing the
message-passing mechanism. This might be hard to achieve if the MA is coded to
provide added resilience, thereby sacrificing compactness as per the extra codes that
implement this added feature. Another aspect that adds complexity to an MA-based
solution is the migration strategy employed to visit multiple nodes, either throughout
the network or in a portion thereof. An inefficient migration strategy incurs added
bandwidth because of the total number of times that one or more MAs hop to
accomplish a certain task. However, a carefully engineered migration strategy
would ostensibly be capable of achieving better results. It thus follows that largesized
MAs implementing an inefficient migration strategy would result detrimental
to the overall system’s performance. In addition, the effectiveness with which an
MA solution provides resilience depends directly on the programmer’s ability to
anticipate and deal with situations that the MA could encounter. In the messagepassing
mechanism, the respective communications protocol daemon running into
an unexpected situation could simply reschedule the data transfer process at a later
time if the current circumstances are unfavorable. Conversely, an MA could remain
stranded at a remote node, perhaps unable to return to the network’s gateway upon
encountering a situation that steered it into a deadlock state. An additional issue that
can be used to argue against MA technology is that of security. To this regard, it is
easy to see that an attacker could inject a malicious agent into a network to disrupt its
normal operation (e.g., as a typical computer network virus). Conversely, one or
more malicious device(s) could be used to disrupt an agent’s normal operation or to
embed a malicious code segment into it. As a result, using MAs can be deemed a
safer option in closed networks where access is controlled. Additionally, wellknown
cryptographic methods, such as digital signatures, can be readily employed
to reduce to some extent the inherent security risks, though some performance
APPLICATIONS OF MOBILE AGENTS IN WIRELESS NETWORKS 119
degradations would be inevitable. However, this would be highly detrimental for
network tasks requiring near real-time response, or in networks formed by devices
with limited hardware resources, given that processing digital signatures entails
additional memory availability and processing capabilities that increases power
consumption.



The many advantages of information markets and their impressive performance in many current applications support great potentials for wide use across many business and technical fields. Studies that test the usefulness of information markets in various application domains and processes are greatly needed.Our extensive literature survey found that research on how information markets are used inside organizations is still in its infancy. Little is known about the impact of the business environment on information market design, incentive structures, and the types of questions that can be investigated via such markets. To put it more simply, we need research on what works and what does not work. Little is also known about the impact of the market on work processes, corporate culture, and formal and informal reporting mechanisms in the organization. 7.1 Information Markets as IT Artifacts From a design view of an information market as an IT artifact, research on designing an information market to meet the requirements of an interesting business problem holds great promise. The information systems research framework (Fig. 5) and the design research guidelines suggested by Hevner et al. [59] can be used to structure the methods and activities performed by researchers designing/studying organizational information markets.