https://dl.ucsc.cmb.ac.lk/jspui/handle/123456789/4738 2026-03-29T06:27:26Z https://dl.ucsc.cmb.ac.lk/jspui/handle/123456789/4775 Title: An Intelligent Traffic Modeling Framework for Managing the Effects of Abrupt Perturbations in order to Prevent Imbalance Leading to Chaos Authors: Rakkesh, S.T. Abstract: Abstract Vehicular traffic congestion continues to remain a critical problem in most urban cities around the world, especially in developing countries. This results in increased delays, driver stress, fuel consumption, air pollution and road accidents. Solutions to this problem have evolved over the years. Initially, the approach was based on the construction of alternative road infrastructure with increased capacity. However, available funds and territorial limitations have proved to be too formidable for continuing the implementation of such solutions. In parallel, traffic lights and roundabouts were introduced in congested intersections, but the increased growth trends of inhabitance in urban cities now demand more advanced and efficient alternative measures to simply augmenting the existing infrastructure. This has paved way for numerous unconventional approaches to be explored by the research community on the field of traffic. Accidents and unexpected roadblocks can occur anytime in a traffic environment. These abrupt external events usually lead the traffic environment to an imbalanced state and result in subsequent congestions formation and chaos around the region where the perturbation has occurred, especially in urban cities of developing nations. This kind of unanticipated incidents often leads to the build-up of long queues of vehicles in urban cities of Sri Lanka due to subsequent congestions formation and sometimes ending in a severe chaos situation. Since traffic environments are highly dynamic and distributed in nature, any solution to solve this unique traffic related problem should also address this dynamicity by vigorously adapting to the changes. Intelligent transportation systems (ITS) have been playing a crucial role in providing excellent solutions for complex traffic problems since last decade onwards. As an emerging new form of wireless networks, vehicular ad-hoc networks (VANETs) have become the trend setter in ITS solutions. VANETs support a large spectrum of decentralized vehicular applications ranging from traffic light optimization solutions to anticipatory vehicular re-routing strategies ensuring contingency in highly volatile situations. Usually, VANET solutions target to build a distributed inter-vehicular communication (IVC) network by extending the in-vehicle communication interfaces which are already available in present-day vehicles. Due to its flexible architectural design principles, VANET is one of the popular choices of x communication strategies used by researchers to build distributed, autonomous and cost-efficient traffic solutions. A unique ITS solution is presented in this dissertation using VANET’s principles to tolerate unanticipated abrupt perturbations which can occur in any traffic environments due to accidents or roadblocks and settle the environment back to an equilibrium state within a reasonable time, preventing subsequent congestions formation and possible escalation into severe chaos. Also, various in-vehicle and inter-vehicular communication strategies have been extensively analyzed and miscellaneous simulation techniques to replicate both microscopic vehicular movements and inter-vehicular communication dynamics discussed in this thesis. The re-routing strategy devised from the study, the proposed VANET solution encompassing multi-faceted vehicle to everything (V2X) communication model and the bidirectionally coupled simulation framework to evaluate both microscopic mobility simulations and the corresponding network level simulations in a synchronized fashion are the core novel scientific contributions of the research work illustrated in this dissertation. 2023-01-01T00:00:00Z https://dl.ucsc.cmb.ac.lk/jspui/handle/123456789/4774 Title: A Study on the Cognitive Complexity Metric of a Software Authors: Wijendra, D. R. Abstract: Abstract The cognitive complexity of a software determines the effort required to understand its source code logic. It can be used to indicate understandability and maintainability, which are predominant quality attributes in software development process. Further, personal profile and source code factors can be stated as major factors associated with cognitive complexity. The inclusion of personal profile results cognitive complexity to be a subjective measurement. However, traditional methods of expressing cognitive complexity are limited only to source code factors to express it as an objective measurement. Moreover, a methodology of relating cognitive complexity to indicate understandability and maintainability cannot be observed. As such, this work has studied the mechanisms of applying cognitive complexity in software development and maintenance processes effectively. Accordingly, the procedures of reducing cognitive complexity to improve understandability and maintainability have been introduced. Expression of cognitive complexity by giving more impact in personal profile is a significant achievement of this research work. The usage of software requirements, its logical diagrams, defects tracing, code quality optimization and refactoring have been introduced as cognitive complexity reduction mechanisms. Those mechanisms have been designed using a computational aid. A meaningful cognitive complexity metric has also been introduced to quantitatively indicate cognitive complexity by considering both personal profile and source code factors. The personal factor involvement of the metric has been introduced using a subjective cognitive weight. The components of reducing cognitive complexity have been evaluated with the duration taken to understand a source code. Accordingly, significant duration reduction has been obtained from proposed components comparing to the current practices to process same scenarios. Therefore, the possibility of proposed mechanisms to gain a less comprehension effort and to achieve a less cognitive complexity can be verified. The proposed cognitive complexity metric has been practically and empirically verified through standard software metric frameworks to prove its stability in real applications. Hence, together with the design to attain a lesser cognitive complexity and the metric to quantitatively indicate the subjective user comprehension effort can be used as significant appliances in software engineering. Keywords: cognitive complexity, cognitive complexity metric, cognitive load, cognitive weight, maintainability, subjectivity, understandability 2023-01-01T00:00:00Z