Multimedia courseware for interactive teaching and learning: students’ needs and perspectives

Education faces many new challenges in meeting the demands of teaching and learning for the 21st century. One of the new challenges is to integrate ICT (Information and communication technologies) in teaching and learning as a means of delivering alternative teaching. Multimedia technology, for example, has the potential to transform a traditional classroom into an unlimited imaginary world. This paper report on development and evaluation of a multimedia courseware for Design and Technology (RBT). An interactive CD was developed using the Adobe Flash CS6 software. Alpha and Beta testing have been carried out in the development process. 6 experts were assigned to evaluate the functionality of the interactive CD. In order to identify the usability of interactive CD, 103 respondents were involved in the survey by filling four-point Likert scaled questionnaire. The findings show that, the level of interactive CD usability is at a high level. Based on this study, there are positive effects that we can see based on the use of multimedia elements in the education system. The meaningful benefits of using multimedia elements for learning include the presentation of various learning styles. The presentation of information usually integrates multimedia elements such as text, graphics, audio and video

G-Snoop: Enhancing TCP performance over wireless networks

Focusing on a general wireless network where a wireless link can be at any link along the sender-to-receiver path, a new TCP enhancement scheme, called Generalized-Snoop (G-Snoop), is proposed. Since many existing applications are built on top of TCP, it is essential that any TCP enhancement scheme should be transparent to the end-systems as well as the fixed networks. To achieve this, G-Snoop only needs to be implemented at the wireless gateways, no other parts of the network require modifications. With G-Snoop, TCP senders are shielded from non-congestion packet loss and thus no unnecessary congestion control mechanisms will be performed. Simulation results show that significant throughout gain can be obtained with G-Snoop.published_or_final_versio

End to End Reliability without Unicast Acknowledgements over Vehicular Networks

The Future Cities Project (http://futurecities.up.pt/) has turned the city of Porto (Portugal) into an urban-scale living lab, where researchers, companies and startups can develop and test technologies, products and services. One of its largest infrastructures is the UrbanSense testbed, consisting of 25 environmental sensing units installed around the city, and another the BusNet, a vehicular ad-hoc network installed in over 400 STCP buses together with 55 Road Side Units (RSU), operated by the UP spin-off Veniam. The data gathered by UrbanSense is carried by BusNet to a storage facility. Because BusNet does not support unicast addressing, there i currently on means to provide end-to-end reliability to the communication, leading to data losses. The goal of this thesis is to explore possibilities to address this problem, designing an application level protocol that provides reliability to the data transfer without requiring unicast addressing. Instead, the protocol should leverage the knowledge about bus routes and geographic location of sensing nodes to target the delivery of the acknowledgements

Survey of unified approaches to integrated-service networks

The increasing demand for communication services, coupled with recent technological advances in communication media and switching techniques, has resulted in a proliferation of new and expanded services. Currently, networks are needed which can transmit voice, data, and video services in an application-independent fashion. Unified approaches employ a single switching technique across the entire network bandwidth, thus, allowing services to be switched in an application-independent manner. This paper presents a taxonomy of integrated-service networks including a look at N-ISDN, while focusing on unified approaches to integrated-service networks.The two most promising unified approaches are burst and fast packet switching. Burst switching is a circuit switching-based approach which allocates channel bandwidth to a connection only during the transmission of "bursts" of information. Fast packet switching is a packet switching-based approach which can be characterized by very high transmission rates on network links and simple, hardwired protocols which match the rapid channel speed of the network. Both approaches are being proposed as possible implementations for integrated-service networks. We survey these two approaches, and also examine the key performance issues found in fast packet switching. We then present the results of a simulation study of a fast packet switching network

Is Our Model for Contention Resolution Wrong?

Randomized binary exponential backoff (BEB) is a popular algorithm for coordinating access to a shared channel. With an operational history exceeding four decades, BEB is currently an important component of several wireless standards. Despite this track record, prior theoretical results indicate that under bursty traffic (1) BEB yields poor makespan and (2) superior algorithms are possible. To date, the degree to which these findings manifest in practice has not been resolved. To address this issue, we examine one of the strongest cases against BEB: $n$ packets that simultaneously begin contending for the wireless channel. Using Network Simulator 3, we compare against more recent algorithms that are inspired by BEB, but whose makespan guarantees are superior. Surprisingly, we discover that these newer algorithms significantly underperform. Through further investigation, we identify as the culprit a flawed but common abstraction regarding the cost of collisions. Our experimental results are complemented by analytical arguments that the number of collisions -- and not solely makespan -- is an important metric to optimize. We believe that these findings have implications for the design of contention-resolution algorithms.Comment: Accepted to the 29th ACM Symposium on Parallelism in Algorithms and Architectures (SPAA 2017

Implementation and evaluation of the sensornet protocol for Contiki

Sensornet Protocol (SP) is a link abstraction layer between the network layer and the link layer for sensor networks. SP was proposed as the core of a future-oriented sensor node architecture that allows flexible and optimized combination between multiple coexisting protocols. This thesis implements the SP sensornet protocol on the Contiki operating system in order to: evaluate the effectiveness of the original SP services; explore further requirements and implementation trade-offs uncovered by the original proposal. We analyze the original SP design and the TinyOS implementation of SP to design the Contiki port. We implement the data sending and receiving part of SP using Contiki processes, and the neighbor management part as a group of global routines. The evaluation consists of a single-hop traffic throughput test and a multihop convergecast test. Both tests are conducted using both simulation and experimentation. We conclude from the evaluation results that SP's link-level abstraction effectively improves modularity in protocol construction without sacrificing performance, and our SP implementation on Contiki lays a good foundation for future protocol innovations in wireless sensor networks