The ability to relate abstract knowledge to real-world experiences is indispensable in the modern society. Therefore the construction of knowledge from real-world contexts is a major issue of education. This issue is not supported by the current learning management systems. In the RAFT project we develop a system to support remote accessible field trips. One of its applications, the mobile coll...

BACKGROUND Data collection in Sub-Saharan Africa has traditionally been paper-based. However, the popularization of Android mobile devices and data capture software has brought paperless data management within reach. We used Open Data Kit (ODK) technology on Android mobile devices during a household survey in the Niger Delta region of Nigeria. OBJECTIVE The aim of this study was to describe t...

Garbage collectors are an important part of many modern language runtimes. Essentially all tools for developing and debugging programs using garbage collection assume the correctness of the collector, and therefore provide no means for detecting garbage collector errors. As a result it is especially important that garbage collector implementations be free of errors. This goal is even more chall...

Many high-level language compilers generate C code and then invoke a C compiler to do code generation, register allocation, stack management, and low-level optimization. To date, most of these compilers link the resulting code against a conservative mark-sweep garbage collector in order to reclaim unused memory. We introduce a new collector, MCC, based on mostly-copying collection, and characte...

grid computing is a term referring to the combination of computer resources from multiple administrative domains to reach a common computational platform. mobile computing is a generic word that introduces using of movable, handheld devices with wireless communication, for processing data. mobile computing focused on providing access to data, information, services and communications anywhere an...

In wireless sensor networks (WSNs), utilizing the unmanned aerial vehicle (UAV) as a mobile data collector for the ground sensor nodes (SNs) is an energy-efficient technique to prolong the network lifetime. Specifically, since the UAV can sequentially move close to each of the SNs when collecting data from them and thus reduce the link distance for saving the SNs’ transmission energy. In this l...

WSNs-Wireless Sensor Networks comprises of small nodes with computation, sensing and wireless communications capabilities. Energy awareness is an essential design for WSNs and hence data broadcasting protocols, routing and power management isspecially designed to meet this requirement. However, the focus is mainly on the routing protocols which differ depending on the network design and applica...

This paper attempts to analyze the propagation characteristics of radio signal inside a partially open drain environment using an empirical approach. The proposed research topic concerns a unique situation in several Asian countries because the drainage systems in these countries differ notably from those in the US and Europe in that the former are partially open on the top while the latter are...

A reference counting garbage collector cannot reclaim unreachable cyclic structures of objects. Therefore, reference counting collectors either use a backup tracing collector seldom, or employ a cycle collector to reclaim cyclic structures. Recently, the first on-the-fly cycle collector, that may run concurrently with program threads, was presented by Bacon and Rajan [3]. This demonstrated the ...