Given the high importance of attendance for university students, upon which the possibility of keeping or losing their places in the course is based, it is essential to replace the inefficient manual method of attendance recording with a more efficient one.  To handle this problem, technology must be introduced into this process. This paper aims to propose an automatic attendance system based on passive Radio Frequency Identification (RFID), fog, and cloud computing technologies (AASCF). The system has three sides. The first one, which is the Client-side; works on collecting the attendance data then sending a copy from it. The second side, which is the Server-side, works on calculating an absence ratio of all the students during the course. The third side is the Fog-server. Data sent by the client-side reaches to the Fog-server which, in turn, sends data to the cloud at the end of the of working time at the university. This paper also reviews the state-of-the-art automatic attendance systems and shows the merits and demerits for each approach by providing a checklist comparison. Unlike the previous works, the proposed system protects data from wasting and ensures its arrival to the cloud even  in cases of connection losing or device crashing, which is the contribution of this paper.

Internet of Things (IoT) contributes to improve the quality of life as it supports many applications, especially healthcare systems. Data generated from IoT devices is sent to the Cloud Computing (CC) for processing and storage, despite the latency caused by the distance. Because of the revolution in IoT devices, data sent to CC has been increasing. As a result, another problem added to the latency was increasing congestion on the cloud network. Fog Computing (FC) was used to solve these problems because of its proximity to IoT devices, while filtering data is sent to the CC. FC is a middle layer located between IoT devices and the CC layer. Due to the massive data generated by IoT devices on FC, Dynamic Weighted Round Robin (DWRR) algorithm was used, which represents a load balancing (LB) algorithm that is applied to schedule and distributes data among fog servers by reading CPU and memory values of these servers in order to improve system performance. The results proved that DWRR algorithm provides high throughput which reaches 3290 req/sec at 919 users. A lot of research is concerned with distribution of workload by using LB techniques without paying much attention to Fault Tolerance (FT), which implies that the system continues to operate even when fault occurs. Therefore, we proposed a replication FT technique called primary-backup replication based on dynamic checkpoint interval on FC. Checkpoint was used to replicate new data from a primary server to a backup server dynamically by monitoring CPU values of primary fog server, so that checkpoint occurs only when the CPU value is larger than 0.2 to reduce overhead. The results showed that the execution time of data filtering process on the FC with a dynamic checkpoint is less than the time spent in the case of the static checkpoint that is independent on the CPU status.

Conventional street lighting control systems is manual control, light sensitive control, and simple timing control while energy consumption and operators are unable to monitor street lights, that significantly disrupts management and maintenance. This work is based on the idea of maximize the maintaining and minimize an energy loss. Much of the energy produced daytime is saved in a solar cell and then will use to glow street lights throughout the night. The system also provides an energy-efficient operation mode by adapting the automated method. The lights switch on/off automatically according to vehicle movement or day/night sensor as well as to reduce management cost and monitor status information for each street lighting unit. In this paper two sensors are utilized that are Light Dependent Resistor (LDR) sensor to signalize a day/night time and Infrared Obstacle (IR) sensors to discover the movement on the street. Arduino microcontroller is utilized as a brain to control the street lighting system. In the other hand sensors data are analyzed and stored in Thingspeak cloud after are sent by Arduino UNO. Experimental results show that the system is stable and reliable as it can be applied as a model system.

Dynamic memory management is an important part of computer systems design. Efficient memory allocation, garbage collection and compaction are becoming increasingly more critical in parallel, distributed and real-time applications. The memory efficiency is related to the fragmentation. Segregation is one of the simplest allocation policies which use a set of free lists, where each list holds blocks of a particular size. When the process requests a memory. The free list for the appropriate size is used to satisfy the request. This paper proposes a scheme to reduce the internal fragmentation of a segregated free list for improving memory efficiency using genetic algorithm (GA) to find the optimal configuration. Because the genetic algorithms (GAs) are largely used in optimization problems, they facilitate a good alternative in problem areas where the number of constraints is too large for humans to efficiently evaluate. This GA is tested under five randomly created workloads to find the best configuration. The results are acceptable when compared with optimal configurations of these workloads.

Nowadays, after the technological development in societies, cloud computing has become one of the most important technologies. It provides users with software, hardware, and platform as remote services over the Internet. The increasing number of cloud users has caused a critical problem in how the clients receive cloud services when the cloud is in a state of instability, as it cannot provide required services and, thus, a delay occurs. Therefore, an algorithm was proposed to provide high efficiency and stability to work, because all existing tasks must operate without delay. The proposed system is an enhancement shortest job first algorithm (ESJF) using a time slice, which works by taking a task in the shortest time first and then the longest first from the queue. Through the experimental results in decreasing the waiting and completion time of the task, as well as taking into account reducing tasks starvation, the result of the proposed ESJF algorithm was compared with the traditional shortest job first (SJF) algorithm. These algorithms were applied when all tasks arrived at the same time, and it proved that the ESJF algorithm works more efficiently compared to SJF.