Elisha Oketch Ochola

Measuring Straight Line Segments Using HT Butterflies

This paper addresses the features of Hough Transform (HT) butterflies suitable for image-based segment detection and measurement. The full segment parameters such as the position, slope, width, length, continuity, and uniformity are related to the features of the HT butterflies. Mathematical analysis and experimental data are presented in order to demonstrate and build the relationship between the measurements of segments and the features of HT butterflies. An effective method is subsequently proposed to employ these relationships in order to discover the parameters of segments. Power line inspection is considered as an application of the proposed method. The application demonstrates that the proposed method is effective for power line inspection, especially for corner detection when they cross poles.

Improving open distance learning efficiency by non-invasive brain computer interface

One of the biggest problems of ODL teaching/learning is that lecturers cannot get the feedback from students in time and modify the teaching materials and styles according to the interaction of students. The burgeoning Brain Computer Interface (BCI) created the possibility of assessing the activities of working memory which is closely related to the knowledge accepting (learning, understanding) efficiency. This research aims to build a real-time teaching and learning efficiency assessing system based on the technique of electroencephalograph (EEG, a kind of non-invasive BCI). The activities of working memory is detected by the system when students learning, based on which both sides of lecturers and students, can modify teaching/learning materials and styles. So a relative higher efficiency of knowledge delivery will be created.

An anti-DoS attack architecture for wireless IT Infrastructure

Widespread deployment of wireless solutions in corporate and government computing infrastructure implies that lots of sensitive information and data is carried over the air. The threats of intrusion and denial of service is real since wireless networks have broadcasted traffic. IEEE 802.11 defines WEP, WPA and WPA2 security protocols as possible countermeasures. The most recent model defined by IEEE, the WPA2 emphasizes data confidentiality, integrity and authentication but pays little attention to availability issues. Management and control frames in WPA2 are still sent in clear making the model vulnerable to DoS attacks. The failure recovery processes require re-authentication and re-association a fact which makes the model easily exploited by various DoS attacks that includes authentication and association frames flooding. In this paper, we propose a drop policy for DoS authentication and Association flooding. We assume deployment of the current IEEE 802.11i provides enough confidentiality, integrity and authentication schemes. We use simulation in OPNET to show that our security model performs better to provide improved security in terms of availability under Denial of service attack.

Denial of Service Attacks in Wireless Sensor Networks with Proposed Countermeasures

A wireless sensor network (WSN) is a network consisting of small nodes with constrained capabilities to sense, collect, and transmit sensed data in many application areas such as the healthcare system, the automotive industry, sports, and open space surveillance. WSNs communicate through wireless mediums and are accessible to anyone, which makes sensor nodes vulnerable to various forms of attack. Considering the energy-constrained nature of sensor nodes, denial of service (DoS) attacks on these nodes are popular. This paper examines DoS attacks and proposes countermeasures based on use of the clustering technique. The method is compared with other related protocols, and the results show that our method is able to effectively detect and defend against DoS attacks in WSNs.

Ambiguity as a Barrier to Information Security Policy Compliance: A Content Analysis

Institutions use the information security (InfoSec) policy document as a set of rules and guidelines to govern the use of the institutional information resources. However, a common problem is that these policies are often not followed or complied with. This study explores the extent to which the problem lies with the policy documents themselves. The InfoSec policies are documented in the natural languages, which are prone to ambiguity and misinterpretation. Subsequently such policies may be ambiguous, thereby making it hard, if not impossible for users to comply with. A case study approach with a content analysis was conducted. The research explores the extent of the problem by using a case study of an educational institution in South Africa.

Location based analysis of AODV performance in the presence of black hole nodes

Mobility and portability of wireless communication devices in Mobile Ad Hoc Networks have introduced data security threats. This is due to the utilization of multiple hops as a result of limited transmission ranges between source and destination nodes. The performance of MANETs under Black Hole attacks can be improved by accurately detecting and eliminating black hole nodes. That is, there are indications to suggest that inaccu-rate Black Hole attack detection and elimination in Mobile Ad Hoc Networks have led to a low network performance. This paper aims to prove the impact Black Hole attacks can have on Mobile Ad Hoc Networks implementing AODV as a routing protocol via simulation. The simulation is conducted using NS3 and NetAnim. This involves the use of a base implementation of AODV as a benchmark for the effects that black hole nodes introduce into a network. Similarly, the AODV implementation that has black Hole nodes present in the network is also performed, to measure the effects black hole nodes introduce. Results indicate that the encounter of a black hole node during transmissions has a devastating effect on the network functionality. The closer the black hole node is to the source node requesting the transmission, the worse the impact. Fortunately, there are few scenarios where the black hole nodes are in the network, but the routing protocol chooses a path that does not include the malicious node. The paper concludes that, even with the introduction of relatively few black hole nodes to the network, there still exist a potential to bring significant disruptions to communication.

Effect of varying node mobility in the analysis of black hole attack on MANET reactive routing protocols

Mobile Ad-hoc Networks (MANETs) features such as open medium, dynamic topology, lack of centralised management and lack of infrastructure expose them to a number of security attacks. Black hole attack is one type of attack that is more common in MANET reactive routing protocols such as Ad-hoc On-demand Distance Vector (AODV) and Dynamic Source Routing (DSR). Black hole attack takes advantage of route discovery process in reactive routing protocols. In this type of attack, a malicious node misleads other nodes in the network by pretending to have the shortest and updated route to a target node whose packets it wants to interrupt. It then redirects all packets destined to a target node to itself and discards them instead of forwarding. This paper analyses the performance of AODV and DSR when attacked by black hole, by varying the mobility of the nodes in the network. The analysis is carried out by simulating scenarios of AODV based MANET and DSR based MANET using Network Simulator 2 (NS-2) and introducing the black hole attack in each of the scenarios. The different scenarios are generated by changing the mobility of the nodes. The performance metrics that are used to do the analysis are throughput, packet delivery ratio and end-to-end delay. The simulation results show that the performance of both AODV and DSR degrades in the presence of black hole attack. Throughput and packet delivery ratio decrease when the network is attacked by black hole because the malicious node absorbs or discards some of the packets. End-to-end delay is also reduced in the presence of a black hole attack because a malicious node pretends to have a valid route to destination without checking the routing table, and therefore shortens the route discovery process. The results also show that throughput decreases slightly when mobility of the nodes is increased in the network. The increase in the speed of the nodes decreases both end-to-end delay and packet delivery ratio.

Beyond watchdog schemes in securing MANET's reactive protocols operating on a dynamic transmission power control technique

Communication is no longer restricted to areas with telecommunication network infrastructure due to the introduction of wireless mobile Ad-hoc Network (MANET) that makes it possible to communicate anytime anywhere, without the support of a pre-existing network infrastructure. Unfortunately, MANET comes with unique features which are neither common to the conventional wired networks nor the cellular wireless networks, hence it presents new security challenges due to malicious attacks vulnerabilities. The operation of MANET routing protocols require that participating nodes cooperate in order to achieve the desired efficiency in information exchange in such a temporal network. The portability and size of MANET devices limit the battery power, and this has led to the implementations of various transmission power-aware schemes in the traditional MANET reactive routing protocols to prolong the networks lifetime. The introduction of the power-aware schemes makes it unreliable to solely depend on the watchdog security mechanisms to secure MANETs against black-hole attacks. This paper presents a framework which overcomes the watchdog schemes weakness in the presence of power-aware routing protocols to accurately detect and eliminate black-hole nodes, thereby improving the network performance.