Abstract: Knowledge modelling, a main activity for the development of Knowledge Based Systems, have no set standards and are mostly done in an ad hoc way. There is a lack of support for the transition from abstract level to implementation. In this paper, a methodology for the development of the knowledge model, which is inspired by both Software and Knowledge Engineering, is proposed. Use of UML which is the de-facto standard for modelling in the software engineering arena is explored for knowledge modelling. The methodology proposed, is used to develop a knowledge model of a knowledge based system for recommending suitable hotels for tourists visiting Mauritius.
Abstract: The Ad Hoc on demand distance vector (AODV) routing protocol is designed for mobile ad hoc networks (MANETs). AODV offers quick adaptation to dynamic link conditions; it is characterized by low memory overhead and low network utilization. The security issues related to the protocol remain challenging for the wireless network designers. Numerous schemes have been proposed for establishing secure communication between end users, these schemes identify that the secure operation of AODV is a bi tier task (routing and secure exchange of information at separate levels). Our endeavor in this paper would focus on achieving the routing and secure data exchange in a single step. This will facilitate the user nodes to perform routing, mutual authentications, generation and secure exchange of session key in one step thus ensuring confidentiality, integrity and authentication of data exchange in a more suitable way.
Abstract: Position based routing protocols are the kinds of
routing protocols, which they use of nodes location information,
instead of links information to routing. In position based routing
protocols, it supposed that the packet source node has position
information of itself and it's neighbors and packet destination node.
Greedy is a very important position based routing protocol. In one of
it's kinds, named MFR (Most Forward Within Radius), source node
or packet forwarder node, sends packet to one of it's neighbors with
most forward progress towards destination node (closest neighbor to
destination). Using distance deciding metric in Greedy to forward
packet to a neighbor node, is not suitable for all conditions. If closest
neighbor to destination node, has high speed, in comparison with
source node or intermediate packet forwarder node speed or has very
low remained battery power, then packet loss probability is
increased. Proposed strategy uses combination of metrics distancevelocity
similarity-power, to deciding about giving the packet to
which neighbor. Simulation results show that the proposed strategy
has lower lost packets average than Greedy, so it has more reliability.
Abstract: Decision Support System (DSS) are interactive
software systems that are built to assist the management of an
organization in the decision making process when faced with nonroutine
problems in a specific application domain. Non-functional
requirements (NFRs) for a DSS deal with the desirable qualities and
restrictions that the DSS functionalities must satisfy. Unlike the
functional requirements, which are tangible functionalities provided
by the DSS, NFRs are often hidden and transparent to DSS users but
affect the quality of the provided functionalities. NFRs are often
overlooked or added later to the system in an ad hoc manner, leading
to a poor overall quality of the system. In this paper, we discuss the
development of NFRs as part of the requirements engineering phase
of the system development life cycle of DSSs. To help eliciting
NFRs, we provide a comprehensive taxonomy of NFRs for DSSs.
Abstract: The nature of wireless ad hoc and sensor networks
make them very attractive to attackers. One of the most popular and
serious attacks in wireless ad hoc networks is wormhole attack and
most proposed protocols to defend against this attack used
positioning devices, synchronized clocks, or directional antennas.
This paper analyzes the nature of wormhole attack and existing
methods of defending mechanism and then proposes round trip time
(RTT) and neighbor numbers based wormhole detection mechanism.
The consideration of proposed mechanism is the RTT between two
successive nodes and those nodes- neighbor number which is needed
to compare those values of other successive nodes. The identification
of wormhole attacks is based on the two faces. The first consideration
is that the transmission time between two wormhole attack affected
nodes is considerable higher than that between two normal neighbor
nodes. The second detection mechanism is based on the fact that by
introducing new links into the network, the adversary increases the
number of neighbors of the nodes within its radius. This system does
not require any specific hardware, has good performance and little
overhead and also does not consume extra energy. The proposed
system is designed in ad hoc on-demand distance vector (AODV)
routing protocol and analysis and simulations of the proposed system
are performed in network simulator (ns-2).
Abstract: Characteristics of ad hoc networks and even their existence depend on the nodes forming them. Thus, services and applications designed for ad hoc networks should adapt to this dynamic and distributed environment. In particular, multicast algorithms having reliability and scalability requirements should abstain from centralized approaches. We aspire to define a reliable and scalable multicast protocol for ad hoc networks. Our target is to utilize epidemic techniques for this purpose. In this paper, we present a brief survey of epidemic algorithms for reliable multicasting in ad hoc networks, and describe formulations and analytical results for simple epidemics. Then, P2P anti-entropy algorithm for content distribution and our prototype simulation model are described together with our initial results demonstrating the behavior of the algorithm.
Abstract: In ad hoc networks, the main issue about designing of protocols is quality of service, so that in wireless sensor networks the main constraint in designing protocols is limited energy of sensors. In fact, protocols which minimize the power consumption in sensors are more considered in wireless sensor networks. One approach of reducing energy consumption in wireless sensor networks is to reduce the number of packages that are transmitted in network. The technique of collecting data that combines related data and prevent transmission of additional packages in network can be effective in the reducing of transmitted packages- number. According to this fact that information processing consumes less power than information transmitting, Data Aggregation has great importance and because of this fact this technique is used in many protocols [5]. One of the Data Aggregation techniques is to use Data Aggregation tree. But finding one optimum Data Aggregation tree to collect data in networks with one sink is a NP-hard problem. In the Data Aggregation technique, related information packages are combined in intermediate nodes and form one package. So the number of packages which are transmitted in network reduces and therefore, less energy will be consumed that at last results in improvement of longevity of network. Heuristic methods are used in order to solve the NP-hard problem that one of these optimization methods is to solve Simulated Annealing problems. In this article, we will propose new method in order to build data collection tree in wireless sensor networks by using Simulated Annealing algorithm and we will evaluate its efficiency whit Genetic Algorithm.
Abstract: Routing security is a major concerned in Wireless
Sensor Network since a large scale of unattended nodes is deployed
in ad hoc fashion with no possibility of a global addressing due to a
limitation of node-s memory and the node have to be self organizing
when the systems require a connection with the other nodes. It
becomes more challenging when the nodes have to act as the router
and tightly constrained on energy and computational capabilities
where any existing security mechanisms are not allowed to be fitted
directly. These reasons thus increasing vulnerabilities to the network
layer particularly and to the whole network, generally. In this paper,
a Dynamic Window Secured Implicit Geographic Forwarding
(DWSIGF) routing is presented where a dynamic time is used for
collection window to collect Clear to Send (CTS) control packet in
order to find an appropriate hoping node. The DWIGF is expected to
minimize a chance to select an attacker as the hoping node that
caused by a blackhole attack that happen because of the CTS rushing
attack, which promise a good network performance with high packet
delivery ratios.
Abstract: Mobile Ad Hoc network is an infrastructure less
network which operates with the coordination of each node. Each node
believes to help another node, by forwarding its data to/from another
node. Unlike a wired network, nodes in an ad hoc network are resource
(i.e. battery, bandwidth computational capability and so on)
constrained. Such dependability of one node to another and limited
resources of nodes can result in non cooperation by any node to
accumulate its resources. Such non cooperation is known as selfish
behavior.
This paper discusses the performance analysis of very well known
MANET single-path (i.e. AODV) and multi-path (i.e. AOMDV)
routing protocol, in the presence of selfish behaviors. Along with
existing selfish behaviors, a new variation is also studied. Extensive
simulations were carried out using ns-2 and the study concluded that
the multi-path protocol (i.e. AOMDV) with link disjoint configuration
outperforms the other two configurations.
Abstract: As mobile ad hoc networks (MANET) have different
characteristics from wired networks and even from standard wireless
networks, there are new challenges related to security issues that
need to be addressed. Due to its unique features such as open nature,
lack of infrastructure and central management, node mobility and
change of dynamic topology, prevention methods from attacks on
them are not enough. Therefore intrusion detection is one of the
possible ways in recognizing a possible attack before the system
could be penetrated. All in all, techniques for intrusion detection in
old wireless networks are not suitable for MANET. In this paper, we
classify the architecture for Intrusion detection systems that have so
far been introduced for MANETs, and then existing intrusion
detection techniques in MANET presented and compared. We then
indicate important future research directions.
Abstract: In a very simple form a Mobile Agent is an independent piece of code that has mobility and autonomy behavior. One of the main advantages of using Mobile Agent in a network is - it reduces network traffic load. In an, ad hoc network Mobile Agent can be used to protect the network by using agent based IDS or IPS. Besides, to deploy dynamic software in the network or to retrieve information from network nodes Mobile Agent can be useful. But in an ad hoc network the Mobile Agent itself needs some security. Security services should be guaranteed both for Mobile Agent and for Agent Server. In this paper to protect the Mobile Agent and Agent Server in an ad hoc network we have proposed a solution which is based on Threshold Cryptography, a new vibe in the cryptographic world where trust is distributed among multiple nodes in the network.
Abstract: Spectrum is a scarce commodity, and considering the spectrum scarcity faced by the wireless-based service providers led to high congestion levels. Technical inefficiencies from pooled, since all networks share a common pool of channels, exhausting the available channels will force networks to block the services. Researchers found that cognitive radio (CR) technology may resolve the spectrum scarcity. A CR is a self-configuring entity in a wireless networking that senses its environment, tracks changes, and frequently exchanges information with their networks. However, CRN facing challenges and condition become worst while tracks changes i.e. reallocation of another under-utilized channels while primary network user arrives. In this paper, channels or resource reallocation technique based on DNA-inspired computing algorithm for CRN has been proposed.
Abstract: Wireless Mesh Networks (WMNs) are an emerging
technology for last-mile broadband access. In WMNs, similar to ad
hoc networks, each user node operates not only as a host but also as a
router. User packets are forwarded to and from an Internet-connected
gateway in multi-hop fashion. The WMNs can be integrated with
other networking technologies i.e. ad hoc networks, to implement a
smooth network extension. The meshed topology provides good
reliability and scalability, as well as low upfront investments. Despite
the recent start-up surge in WMNs, much research remains to be
done in standardizing the functional parameters of WMNs to fully
exploit their full potential. An edifice of the security concerns of
these networks is authentication of a new client joining an integrated
ad hoc network and such a scenario will require execution of a multihop
authentication technique. Our endeavor in this paper is to
introduce a secure authentication technique, with light over-heads
that can be conveniently implemented for the ad-hoc nodes forming
clients of an integrated WMN, thus facilitating their inter-operability.
Abstract: In this paper, a new approach based on the extent of
friendship between the nodes is proposed which makes the nodes to
co-operate in an ad hoc environment. The extended DSR protocol is
tested under different scenarios by varying the number of malicious
nodes and node moving speed. It is also tested varying the number of
nodes in simulation used. The result indicates the achieved
throughput by extended DSR is greater than the standard DSR and
indicates the percentage of malicious drops over total drops are less
in the case of extended DSR than the standard DSR.
Abstract: Wireless ad hoc nodes are freely and dynamically
self-organize in communicating with others. Each node can act as
host or router. However it actually depends on the capability of
nodes in terms of its current power level, signal strength, number
of hops, routing protocol, interference and others. In this research,
a study was conducted to observe the effect of hops count over
different network topologies that contribute to TCP Congestion
Control performance degradation. To achieve this objective, a
simulation using NS-2 with different topologies have been
evaluated. The comparative analysis has been discussed based on
standard observation metrics: throughput, delay and packet loss
ratio. As a result, there is a relationship between types of topology
and hops counts towards the performance of ad hoc network. In
future, the extension study will be carried out to investigate the
effect of different error rate and background traffic over same
topologies.
Abstract: Connected dominating set (CDS) problem in unit disk
graph has signi£cant impact on an ef£cient design of routing protocols
in wireless sensor networks, where the searching space for a
route is reduced to nodes in the set. A set is dominating if all the
nodes in the system are either in the set or neighbors of nodes in the
set. In this paper, a simple and ef£cient heuristic method is proposed
for £nding a minimum connected dominating set (MCDS) in ad hoc
wireless networks based on the new parameter support of vertices.
With this parameter the proposed heuristic approach effectively
£nds the MCDS of a graph. Extensive computational experiments
show that the proposed approach outperforms the recently proposed
heuristics found in the literature for the MCD
Abstract: Through the course of this paper we define Business Case Management and its characteristics, and highlight its link to knowledge workers. Business Case Management combines knowledge and process effectively, supporting the ad hoc and unpredictable nature of cases, and coordinate a range of other technologies to appropriately support knowledge-intensive processes. We emphasize the growing importance of knowledge workers and the current poor support for knowledge work automation. We also discuss the challenges in supporting this kind of knowledge work and propose a novel approach to overcome these challenges.
Abstract: In this paper, a Cooperative Multi-robot for Carrying
Targets (CMCT) algorithm is proposed. The multi-robot team
consists of three robots, one is a supervisor and the others are
workers for carrying boxes in a store of 100×100 m2. Each robot has
a self recharging mechanism. The CMCT minimizes robot-s worked
time for carrying many boxes during day by working in parallel. That
is, the supervisor detects the required variables in the same time
another robots work with previous variables. It works with
straightforward mechanical models by using simple cosine laws. It
detects the robot-s shortest path for reaching the target position
avoiding obstacles by using a proposed CMCT path planning
(CMCT-PP) algorithm. It prevents the collision between robots
during moving. The robots interact in an ad hoc wireless network.
Simulation results show that the proposed system that consists of
CMCT algorithm and its accomplished CMCT-PP algorithm
achieves a high improvement in time and distance while performing
the required tasks over the already existed algorithms.
Abstract: Data mining uses a variety of techniques each of which is useful for some particular task. It is important to have a deep understanding of each technique and be able to perform sophisticated analysis. In this article we describe a tool built to simulate a variation of the Kohonen network to perform unsupervised clustering and support the entire data mining process up to results visualization. A graphical representation helps the user to find out a strategy to optmize classification by adding, moving or delete a neuron in order to change the number of classes. The tool is also able to automatically suggest a strategy for number of classes optimization.The tool is used to classify macroeconomic data that report the most developed countries? import and export. It is possible to classify the countries based on their economic behaviour and use an ad hoc tool to characterize the commercial behaviour of a country in a selected class from the analysis of positive and negative features that contribute to classes formation.
Abstract: As originally designed for wired networks, TCP (transmission control protocol) congestion control mechanism is triggered into action when packet loss is detected. This implicit assumption for packet loss mostly due to network congestion does not work well in Mobile Ad Hoc Network, where there is a comparatively high likelihood of packet loss due to channel errors and node mobility etc. Such non-congestion packet loss, when dealt with by congestion control mechanism, causes poor TCP performance in MANET. In this study, we continue to investigate the impact of the interaction between transport protocols and on-demand routing protocols on the performance and stability of 802.11 multihop networks. We evaluate the important wireless networking events caused routing change, and propose a cross layer method to delay the unnecessary routing changes, only need to add a sensitivity parameter α , which represents the on-demand routing-s reaction to link failure of MAC layer. Our proposal is applicable to the plain 802.11 networking environment, the simulation results that this method can remarkably improve the stability and performance of TCP without any modification on TCP and MAC protocol.