This study proposes a multi-pass compiler with code optimized abstract syntax tree based on a subset of C# as the source and C constructs as the target, with the view to enhancing the understanding of compiler design, which conceptually has been a rather difficult discourse.A single-pass compiler allows a single traversal over the source code or intermediate form.This does not allow for a distributed compilation and modular development.On the other hand, the proposed scheme decouples the type-checker from the abstract syntax tree, thus separating them into independent segments that allows a multi-pass over the source code; this in turn provides a mechanism for modular development, which encourages distributed compilation.The proposed scheme constructs the abstract syntax tree before the typechecking, thus allowing another tranversal on the intermediate form of the source code.An optimised tree was constructed after code optimisation had been conducted.The scheme is based on only small subset of C# constructs.Further study would be focused on adding more constructs.

Extensible Markup Language (XML) is the standard medium for data exchange among businesses over the Internet, hence the need for effective management. However, since XML was not designed for storage and retrieval, its management has become an open research area in the database community. Existing mapping techniques for XML-to-relational database adopt either the structural mapping or the model mapping. Though numerous mapping approaches have been developed, mapping and reconstruction time had been problematic, especially when the document size is large and can hardly fit into main memory. In this research, an application codenamed XAPP, a new lightweight application that adopts a novel model mapping approach was developed using Simple API for XML (SAX) parser. XAPP accepts a document with or without Document Type Definition (DTD). It implements two algorithms: one maps XML data to a relational database and improves mapping time, and the other reconstructs an XML document from a relational database to improve reconstruction time and minimise memory usage. The performance of XAPP was analysed and compared with the Document Object Model (DOM) algorithm. XAPP proves to perform significantly better than the DOM-based algorithm in terms of mapping and reconstruction time, and memory efficiency. The correctness of XAPP was also verified.

Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-Coronavirus-2 or SARS-CoV-2), which came into existence in 2019, is a viral pandemic that caused coronavirus disease 2019 (COVID-19) illnesses and death. Research showed that relentless efforts had been made to improve key performance indicators for detection, isolation, and early treatment. This paper used Deep Transfer Learning Model (DTL) for the classification of a real-life COVID-19 dataset of chest X-ray images in both binary (COVID-19 or Normal) and three-class (COVID-19, Viral-Pneumonia or Normal) classification scenarios. Four experiments were performed where fine-tuned VGG-16 and VGG-19 Convolutional Neural Networks (CNNs) with DTL were trained on both binary and three-class datasets that contain X-ray images. The system was trained with an X-ray image dataset for the detection of COVID-19. The fine-tuned VGG-16 and VGG-19 DTL were modelled by employing a batch size of 10 in 40 epochs, Adam optimizer for weight updates, and categorical cross-entropy loss function. The results showed that the fine-tuned VGG-16 and VGG-19 models produced an accuracy of 99.23% and 98.00%, respectively, in the binary task. In contrast, in the multiclass (three-class) task, the fine-tuned VGG-16 and VGG-19 DTL models produced an accuracy of 93.85% and 92.92%, respectively. Moreover, the fine-tuned VGG-16 and VGG-19 models have MCC of 0.98 and 0.96 respectively in the binary classification, and 0.91 and 0.89 for multiclass classification. These results showed strong positive correlations between the models’ predictions and the true labels. In the two classification tasks (binary and three-class), it was observed that the fine-tuned VGG-16 DTL model had stronger positive correlations in the MCC metric than the fine-tuned VGG-19 DTL model. The VGG-16 DTL model has a Kappa value of 0.98 as against 0.96 for the VGG-19 DTL model in the binary classification task, while in the three-class classification problem, the VGG-16 DTL model has a Kappa value of 0.91 as against 0.89 for the VGG-19 DTL model. This result is in agreement with the trend observed in the MCC metric. Hence, it was discovered that the VGG-16 based DTL model classified COVID-19 better than the VGG-19 based DTL model. Using the best performing fine-tuned VGG-16 DTL model, tests were carried out on 470 unlabeled image dataset, which was not used in the model training and validation processes. The test accuracy obtained for the model was 98%. The proposed models provided accurate diagnostics for both the binary and multiclass classifications, outperforming other existing models in the literature in terms of accuracy, as shown in this work.

Scientists succeeded in implementing conventional public switch telephone network (PSTN) into internet protocol by launching H.323 IP telephony.The irrelevant and unknown captions in H.323, computer scientists have replaced H.323 by Session Initiation Protocol (SIP) for Voice-over-IP (VoIP).However, the security of voice communication over IP is still a major concern.Besides, security and performance contradict features.VoIP exhibits a quality-of-service requirements that are sensitive to time.Example of such QoS requirements are delay, jitter, and packet loss.Integrating Internet Protocol Security (IPsec) with Generic Routing Encapsulation (GRE) encrypts and authenticate packets from the sender to receiver, but that raises the question of performance as VoIP is time sensitive.Consequently, three codecs were evaluated to determine the efficiency of each on GRE and IPsec implementation on Internet Protocol version 4 and Internet Protocol version 6 (IPv4 and IPv6), respectively.The topology design and device configuration in this study adopted Graphic Network Simulator 3 (GNS3) and Distributed Internet Traffic Generator (D-ITG) to generate VoIP traffic.The evaluation revealed that the G.723.1 codec achieved better results on IPv4 and IPv6 over GRE with IPsec than other codecs used in the experiment.Furthermore, the codec of choice is a major factor in IPsec VoIP deployment, as also revealed in this study.

This paper addresses the development of entropy generation in the flow and heat transfer of an electrically conducting couple stress fluid film down an inclined heated plate. The balanced momentum and energy equations for the couple stress fluid are formulated based on the first and second laws of thermodynamics, the equations are non-dimensionalized and solutions are constructed based on simplifying assumptions. Variations of thermo-physical parameters are conducted on the velocity and temperature profiles including skin friction, heat transfer rate, entropy generation rate and Bejan number are shown graphically with extensive discussions. The effect of increasing couple stresses on the thin film fluid on the heated plate turns out to enhance the flow velocity and lowers the temperature distribution across the inclined plate. The result of the computation is useful in various metallurgical engineering and industrial processes.

The primary purpose of Denial of Service attack (DoS) is to cripple resources so that the resources are made unavailable to the legitimate users. Due to the inadequate monitoring of activities on the network, it has resulted into huge financial losses. Bandwidth which is one of the resources being used on the network, if not properly monitored could result into misused and attack. This paper proposes a real time system for securing and monitoring the amount of bandwidth consumed on the network using the multi-agent framework technology. It also keeps a record of internet protocol (IP) addresses visiting the network and may be used as a starting point for the aspect of response in providing a comprehensive solution to DoS attacks. The bandwidth is pre-entered and an agent is assigned to monitor bandwidth consumption rate against the set threshold. If the bandwidth is consumed above the bandwidth limit and time set, then a DoS attack is suspected taking into considerations the DoS attack framework This framework can be used as a replicate of what happen in the network scenario environment.

The soil is composed of several nutrients which are important for the effective growth of plants. Nitrogen, phosphorus, and potassium are micronutrients which are very important for plant growth. There have been several methods and soil tests developed to test the compositions of these nutrients in the soil. Interpreting the results gotten from such tests has been a herculean task for farmers. Employing the use of a soft computing method to interpret such result would be a noble idea. In this paper, we describe the use of fuzzy logic to interpret the values of nitrogen, phosphorus, and potassium (NPK) gotten from conventional soil test to know their levels in the soil and predict possible NPK inputs.

The security problems arising from activities of terrorists, kidnappers and human traffickers in the world, at large, can be tackled using Information and Communication Technology (ICT) related approaches. This paper presents the framework of smart objects and Internet of Things (IoT) based system for achieving cost effective and time saving combat of human trafficking and kidnapping. The major components of the system are Sensor Processing Station (SPS), Media Server Station (MSS), Smart Engine Server (SES) and Digital Situation Room (DSR). The SPS is for signal sensing via a number of workstations equipped with video camera sensors, Radio Frequency Identification Card (RFID) tags to the Global Positioning System (GPS) receivers and body worn sensors while MSS will capture and store data from the sensor processing units on the cloud server. The SES will perform logical reasoning of the system such as motion detection, face recognition, position tracking and activities recognition, DSR will be used to monitor events in real-time and on-demand modes based on Internet Protocol version 6 (IPv6)-enabled communications. The work presents an integration of different technologies towards combating human trafficking and kidnapping with a view to enhance existing piecewise development.

In this paper, we carry out an extensive survey of various mobile agent systems that have been utilized in solving university course time tabling problem. University time tabling is an NP-hard problem which has been researched by vast amount of researchers. This is because it is a scheduling problem faced by many universities. This scheduling problem involves a number of hard (mandatory) constraints as well as soft (a lot more flexible) constraints that must be satisfied in order to generate an efficient time-table. A number of methods have been adopted in solving the university course time tabling problem such as the use of linear numberings, evolutionary algorithms, graph coloring among others. One recent technique employed involves mobile agents. Mobile agents are simply software agents which move from system to system within the network transporting both their state and code. They are not bound to the system where their execution begins. This work will involve the analysis of such systems used for university course timetabling in order to highlight their advantages and disadvantages. Keywords—Mobile Agent, University Course Time tabling, Hard Constraints and Soft Constraints. ________________________________________________________________________________________________________

Timetabling forms an important part of most educational systems. This is because most educational institutes largely rely on time tables for their day to day activities. A number of these institutions rather use the very strenuous and slow manual time tabling systems. This results in problems such as inaccurate and poorly managed timetables. In this paper, we propose a design solution towards solving the timetabling problem which uses agent technology. We also examine how the use of an agent based system can help to solve some of the constraints in time table management. The constraints are categorized as both soft constraint (those constraints which can be violated without having a significant impact on the time table's efficiency) and hard constraints (those constraints that must not be violated else the time table generated will be inefficient). The system was designed using modeling tools from the Unified Modeling Language (UML) set. Program development was done in Java using the Netbeans 7.2 integrated development environment. The Java Agent Development Framework – JADE was adopted as the mobile agent platform. A rudimentary time table was generated as a test case. Keywords—Timetabling, Agent technology, Hard and Soft constraints ________________________________________________________________________________________________________

Memory management concerns the process of managing the computer memory, in particular, the main memory, which is an expensive resource of the computer system.In this study, a mobile agent was developed for monitoring memory usage in a network.Monitoring the memory usage of systems in a network is essential in a multiprocessing and multitasking environment due to fact that some processes invoked at startup or those running on the background can consume physical memory and reduce the available memory in their idle states; this way, they reduce the efficiency of the system.Monitoring memory helps to increase the performance of the system and enhance the efficiency of the network.The features of the mobile agent were modeled using the Unified Modelling Language.Programming was done in Java and implementation adopted the Java Agent Development Environment (JADE), a versatile mobile agent platform.A number of computer systems were paired and the monitoring agent system was successfully deployed.

The heart is a key organ of the human system which pumps and circulates blood throughout the body. Its failure to perform thesefunctions often leads to total breakdown of the entire body system and in most cases results in death. In several countries of theworld, significant numbers of heart failure patients are being reported dead due to inaccurate and untimely diagnosis. Recently,expert system approach, which is anchored on Information Technology, has emerged as a strong tool for solving this problem.This paper reports on the development of aWeb and Fuzzy Logic-based Expert System for the diagnosis of heart failure disease.The proposed system consists of a Knowledge Base (which is made up of a Database), a Fuzzy Logic component, a FuzzyInference Engine and a Decision Support Engine which comprises of cognitive and emotional filter as well as Tele-medicinefacilities. The system was implemented using Hypertext Preprocessor (PHP), JavaScript and Hypertext Mark-up Language(HTML) with My Structured Query Language (MySQL) as the Database Management System. Performance analysis based ondata on selected heart failure patients and survey of some experts on heart failure disease at the State Specialist Hospital, Akure,Nigeria shows satisfactory performances of the system.

Differential equations arise in mathematics, physics,medicine, pharmacology, communications, image processing and animation, etc. An Ordinary Differential Equation (ODE) is a differential equation if it involves derivatives with respect to only one independent variable which can be studied from different perspectives, such as: analytical methods, graphical methods and numerical methods. This research paper therefore revises the standard Runge - Kutta fourth order algorithm by using compiler techniques to dynamically evaluate the inputs and implement the algorithm for both first and second order derivatives of the ODE. We have been able to develop and implement the software that can be used to evaluate inputs and compute solutions (approximately and analytically) for the ODE function at a more efficient rate than the traditional method.

In this work, the second law analysis for a reactive couple stress fluid flowing steadily through a channel filled with porous material is investigated. Based on perturbation method, analytical expressions for fluid velocity and temperature are derived and used to compute entropy generation rate, irreversibility distribution ratio in the flow field and results are presented graphically and discussed.

End-user acceptance of information systems (IS), including enterprise systems (ES) is critically important for the success or effectiveness of such technologies for adopting organizations. While prior research has focused on such issues in the developed West, very little is known about workers' perceptions of ES acceptance or adoption in the developing world. This study was designed to add to the growing body of work in the area by using empirical data collected in Nigeria. We employed symbolic acceptance to enrich insight instead of usage adoption, which is commonly used in the literature. We drew from relevant theoretical frameworks in developing the research model, which was tested with data collected from a survey. Using the partial least square technique (PLS) for data analysis, support was found for the five hypotheses formulated herein. Namely, performance and effort expectancies, social influence, facilitating conditions, and attitude toward ES were found to have significant, positive impacts on ES symbolic acceptance. The implications of the study findings for both research and practice are discussed, and conclusions are drawn.

Mobile agent is becoming an emerging tool for monitoring and managing computer networks. Its usefulness in this regard emanates from its ability to communicate with other agents and devices, and navigate a computer network to collect data and take actions autonomously. In this research, an investigation of the use of an agent-based system to monitor the software tools on the nodes of a computer network is carried out. The proposed framework adopts a multi-agent system approach combining a static server agent with a mobile monitor agent which move around and extract data from each node via the server agent. The system was tested in a computer network environment which is characterized by a Windows NT. The programming and mobility infrastructure is the C\#, an object-oriented and multifunctional programming scheme. The performance of the proposed agent-based system and Remote MONitoring (RMON) system are simulated and the results obtained show the cost of service, query time and delay overhead is lower in the agent-based system than that of RMON.

Solar water heating is a process of tapping energy from the sun for the purpose of raising the temperature of water from local water supply to some desirable higher temperature. Water left in a container and exposed to the sun, has been observed to increase in temperature. However, this natural gain of temperature is not usually efficient; partly because water is a poor absorber of solar energy and partly because a large chunk of energy gain is used in evaporation of water, which will not result into temperature raise. A solar water heater was designed, constructed and tested in Akure, South West, Nigeria (Latitude 7.30 o N and Longitude 5.25 o E). A flat plate collector covered with double glazing layers at 20 o angle of tilt to the horizontal was employed. The surface of the collector was darkened to improve its absorption capacity. Readings were taken for a period of six days. With an ambient temperature of 36 o C, a maximum hot water temperature of 73 o C was recorded during the experiment. In addition, hourly collector’s efficiency increased slightly until 2.00 when steep increase was obtained which peaked at 92% at 4.00 pm. The outcome of the experiments established the fact that solar water heater is feasible in South West Nigeria, and of course, in most parts of the country, since insolation is even higher in most other parts of the country, particularly South East and the Northern regions. Keywords: Solar water heater, insolation, radiation, solar energy, thermosiphon.

Monitoring is an aspect of network management aimed at ensuring optimal performance of the network and that the users play by the rules. This paper presents the design of a mobile agent for monitoring the activities of users in a network. Users’ activities can be localized on their personal workstation or extended to the enterprise network and the Internet, in which case it can impact on the subscribed bandwidth, which is a shared resource of the corporate entity that they represent. All users hope to work in an environment of unlimited resources, including disk space, RAM and bandwidth. However, though the cost of these computing resources have reduced significantly owning to advances in microelectronic technology, they are still far from being free and inexhaustible. In this research, we design a mobile agent tool that can monitor users’ activities in a network environment with a view to enhancing the effective utilisation of system resources, and in particular, the physical memory. The aim is to enable optimal resource utilisation in the network environment. In this paper, we define a mathematical formulation of user activities, load overhead of mobile agents and itinerary partition to avoid the over-bloating problem. The architecture of the mobile agent is explained. Keywords: Mobile Agent; System resources; Computer network; Code Mobility; Monitoring