About Omnet Project Team

We consider the problem of neighbor discovery in ad hoc network which is full duplex and uses directional antennas. Directional transmission is prerequisite for some ad hoc networking applications and makes the neighbor discovery less efficient than omni-directional broadcast. Full duplex enables simultaneous transmission and reception and facilitates the directional neighbor discovery.

We present a simple one way handshaking algorithm and feasible decision rules for terminating the neighbor discovery procedure. The effect of transmission error and the collision on the algorithm is also considered. At the same time, the performance of the algorithm is analyzed. Lastly, simulations are given to show the effectiveness and efficiency of the algorithm.

We propose employing receiver cooperation in centralized topology control to improve energy efficiency as well as network connectivity. The idea of transmitter cooperation has been widely considered in topology control to improve network connectivity or energy efficiency. However, receiver cooperation has not previously been considered in topology control. In particular, we show that we can improve both connectivity and energy efficiency if we employ receiver cooperation in addition to transmitter cooperation.

Consequently, we conclude that a system based both on transmitter and receiver cooperation is generally superior to one based only on transmitter cooperation. We also show that the increase in network connectivity caused by employing transmitter cooperation in addition to receiver cooperation is at the expense of significantly increased energy consumption. Consequently, system designers may opt for receiver-only cooperation in cases for which energy efficiency is of the highest priority or when connectivity increase is no longer a serious concern.

In a mobile ad-hoc network, to establish a stable routing path is one of the important technical issues to transmit data from source to destination by multi-hop transmission. Mobile ad-hoc network has time varying channels, and traffic congestion or unstable link condition can be severe problems. To solve those problems, multi-path routing protocols were proposed.

Conventional multi-path routing, however, requires much more nodes and power consumption. In this paper, we propose partial multi-path routing with interference avoidance. The proposed routing does not establish another full routing path but establish a partial multi-path to complement some poor links, and the routing paths have enough distance from each other to reduce path interference.

Route establishment between source and destination is a difficult process in mobile ad hoc network. Many approaches have been developed to find a route from source to destination without considering the stability of the nodes and its link life time. It affects the QoS parameters such as throughput, packet loss, delay, packet delivery ratio. So, in this proposed work a link breakage prediction algorithm is added to the AODV protocol.

By using signal strengths from the received packets the link breakage time is predicted and sends a warning message to the source node of active route if the link is soon to be broken. Also the next optimal route to the destination node will be elected before the breakage of any actual route’s link.

Dynamic topology and limited resources are major limitations that make intrusion detection in mobile adhoc network (MANET) a difficult task. In recent years, several anomaly detection techniques were proposed to detect malicious nodes using static and dynamic baseline profiles, which depict normal MANET behaviors.

In this research, we investigated different baseline profile methods and conducted a set of experiments to evaluate their effectiveness and efficiency for anomaly detection in MANETs using C-means clustering technique. The results indicated that a static baseline profile delivers similar results to other baseline profile methods. However, it requires the least resource usage while a dynamic baseline profile method requires the most resource usage of all the baseline models.

Band Codes (BC) have been recently proposed as a solution for controlled-complexity random Network Coding (NC) in mobile applications, where energy consumption is a major concern. In this paper, we investigate the potential of BC in a peer-to-peer video streaming scenario where malicious and honest nodes coexists. Malicious nodes launch the so called pollution attack by randomly modifying the content of the coded packets they forward to downstream nodes, preventing honest nodes from correctly recovering the video stream.

Whereas in much of the related literature this type of attack is addressed by identifying and isolating the malicious nodes, in this work we propose to address it by adaptively adjusting the coding scheme so to introduce resilience against pollution propagation. We experimentally show the impact of a pollution attack in a defenseless system and in a system where the coding parameters of BC are adaptively modulated following the discovery of polluted packets in the network. We observe that just by tuning the coding parameters, it is possible to reduce the impact of a pollution attack and restore the quality of the video communication.

Many applications, such as Intelligent Transport System (ITS), and mobile multimedia, use Internet-based Vehicular Ad Hoc Networks (IVANETs). In IVANETs, users often access multimedia content from anywhere using Internet connectivity to remote video streaming servers. Due to the high mobility of the nodes in IVANETS, however, maintaining Quality of Service (QoS) for these video streaming applications with respect to parameters such as jitter, throughput, buffering, and transmission delay is a challenging task. To address these challenges, we propose a new QoSaware Hierarchical Web Caching (QHWC) scheme in IVANETs.

We propose two new metrics, Load Utilization Ratio (LUR) and Query to Connectivity Ratio (QCR), to maintain the QoS for various video streaming applications in IVANETs. We compare the performance of our proposed QHWC scheme, with past approaches, such as Dynamic Service, Weighted Segment, and Machine Learning based using various parameters such as QCR, communication cost, query delay, Cache hit ratio, Query Generation Rate, Invalidation cost, and Cache update interval. Our results demonstrate that the proposed QHWC scheme yields an average decrease of 16.75 % and 22 % in communication Cost and Query Delay, respectively, and an average increase of 9.31 % in Cache Hit Ratio. Moreover, the Invalidation Cost reduces by 26.26 % (on average) with our proposed scheme compared to other schemes.

We present a novel system that optimizes the video delivery by mapping network conditions (QoS) to the QoE without penetrating video packets.

It takes the advantage of the Scalable Video Coding (SVC) that can organize video streams into different layers. Our approach helps to maximize the QoE with respect to capacity constraints.

This demonstration shows a new type of HTTP adaptive streaming (HAS) for mobile users. We will present an anticipatory HAS policy that adapts video quality based on a prediction of the wireless channel state. By anticipating a poor channel state and by reducing video quality in advance, this policy maximizes the number of seconds in the user’s play-out buffer before coverage is lost.

Even in difficult coverage situations such as tunnels and elevators, our approach reaches outstanding fluency without decreasing the average video bit-rate. With this anticipatory buffering technique users require no channel resources at low channel state, which increases spectral efficiency. Our solution is based on an modified player application and will be demonstrated on off-the-shelf Smartphones in a conventional 4G network.

This paper illustrates the implementation of a speech-to-speech translation humanoid robot in the domain of medical care. At this stage, the proposed system is a one-way translation that is designed to help English speaking patients describe their symptoms to Korean doctors or nurses. A humanoid robot is useful because it can be extended to reach out to people in need first and may substitute the role of human workers, unlike laptops or tablets.

The system consists of three main parts – speech recognition, English-Korean translation, and Korean speech generation. It utilizes CMU Sphinx-4 as a speech recognition tool. English-Korean translation in this system is based on the rule-based translation. The success rate of the translation shows reliable results from an experiment with a closed scenario.