Access Layer Research Articles

Energy-efficient Cluster-based Mechanism for WBAN Communications for Healthcare Applications

Wireless body area networks (WBANs) are formed with the help of tiny health monitoring sensors on the human body in order to collect and communicate the human personal data. WBANs provides a solution to facilitate the tasks performed in the medical sector, and minimize the chances of errors during the process of medical diagnosis. However, using an expensive key management method is not feasible in highly resource-constrained WBANs. Therefore, we propose and evaluate an energy-efficient key management scheme for WBANs that takes into account available resources of a node during the whole life cycle of key management. Our proposed scheme is a cluster-based hybrid security energy efficient framework. By using multiple clusters, energy-efficiency can be ensured. The performance comparison of our proposed cluster-based key management scheme and low-energy adaptive clustering hierarchy (LEACH)-based key agreement scheme and energy – efficient mechanism shows that the proposed scheme is more energy-efficient, and provides better network lifetime. General Terms Medium access layer (MAC), low-rate (LR) , PHY, Radio Frequency (RF),DLL

Environment-Aware Virtual Slice Provisioning in Green Cloud Environment

Environmental footprint resulting from datacenters activities can be reduced by both energy efficiency and renewable energy in a complementary fashion thanks to cloud computing paradigms. In a cloud hosting multi-tenant applications, virtual service providers can be provided with real-time recommendation techniques to allocate their virtual resources in edge, core, or access layers in an optimal way to minimize costs and footprint. Such a dynamic technique requires a flexible and optimized networking scheme to enable elastic virtual tenants spanning multiple physical nodes. In this paper, we investigate an environment-aware paradigm for virtual slices that allows improving energy efficiency and dealing with intermittent renewable power sources. A virtual slice consists of optimal flows assigned to virtual machines (VMs) in a virtual data center taking into account traffic requirements, VM locations, physical network capacity, and renewable energy availability. Considering various cloud consolidation schemes, we formulate and then propose an optimal solution for virtual slice assignment problem. Simulations on the GSN showed that the proposed model achieves better performance than the existing methods with respect to network footprint reductions.

Wireless sensor network virtualization: early architecture and research perspectives

Wireless sensor networks (WSNs) have become pervasive and are used in many applications and services. Usually the deployments of WSNs are task oriented and domain specific; thereby precluding re-use when other applications and services are contemplated. This inevitably leads to the proliferation of redundant WSN deployments. Virtualization is a technology that can aid in tackling this issue, as it enables the sharing of resources/infrastructure by multiple independent entities. In this paper we critically review the state of the art and propose a novel architecture for WSN virtualization. The proposed architecture has four layers (physical layer, virtual sensor layer, virtual sensor access layer and overlay layer) and relies on the constrained application protocol (CoAP). We illustrate its potential by using it in a scenario where a single WSN is shared by multiple applications; one of which is a fire monitoring application. We present the proof-of-concept prototype we have built along with the performance measurements, and discuss future research directions.

Development of Multi-modal Result Processing Software for Tertiary Institution

Result processing is a major task for any educational institution. In the past, result processing software has been written on different platform such as stand-alone database system, distributed system e.t.c. The era of web based multitier system has necessitated that these software be reengineered. This paper presents the re-engineering of result processing software of the Yaba College of Technology into a multi-modal system. The system analysis of existing software was conducted to know people pains and develop the requirement for the new system. A multimodal, 3-teir (separating the application into data access layer, program logic layer and the user interface) methodology was adopted in re-writing this software. The tools used include visual studio, Borland Delphi and SQL Server database. A modular design approach was adopted with five major modules designed each module serve as an interface for specific user group with assign privileges to ensure people only manipulate data that belongs to them. The implementation produced a robust, highly secured, multimodal system. The system was tested and found to cope with change in policies, unavailability of staff which might be due to industrial strike action, occasional unavailability of network and power failure. It operates in online and offline mode as such it works well and is efficient in managing students’ results seamlessly. It has ability for forward and backward integration with student’s portal; this has made the software highly efficient as registration data are handled directly by the portal while results are posted on the portal. General Terms Software Engineering

Trust Based Dynamic Bandwidth Allocation Scheme for Ethernet Passive Optical Networks

Recently, Ethernet Passive Optical Network (EPON) is a significant solution in the access layer of network that can provide large amount of bandwidth for different kind of traffic. In this paper, we propose a dynamic bandwidth allocation scheme based on the trust based VCG-Kelly mechanism. To enhance the EPON system performance, the proposed scheme can take into account the measure of each ONU's payoff variation succeeding at a given bandwidth allocation. By considering the current outcome, ONUs adaptively select their bid strategies and the OLT dynamically allocates bandwidth to reach a certain desired EPON outcome. In addition, we also consider the network security situation, which reflects what is happening in the EPON network including both the offense and defense behaviors. During this iterative learning approach, the EPON system can converge to a stable network state. Evidences from simulations demonstrate that the proposed scheme outperforms the existing schemes.

Fundamental limits of energy harvesting communications

Wireless networks composed of energy harvesting devices will introduce several transformative changes in wireless networking as we know it: energy self-sufficient, energy self-sustaining, perpetual operation; reduced use of conventional energy and accompanying carbon footprint; untethered mobility; and an ability to deploy wireless networks in hard-to-reach places such as remote rural areas, within structures, and within the human body. Energy harvesting brings new dimensions to the wireless communication problem in the form of intermittency and randomness of available energy, which necessitates a fresh look at wireless communication protocols at the physical, medium access, and networking layers. Scheduling and optimization aspects of energy harvesting communications in the medium access and networking layers have been relatively wellunderstood and surveyed in the recent paper [1]. This branch of literature takes a physical layer rate-power relationship that is valid in energy harvesting conditions under large-enough batteries and long-enough durations between energy harvests so that information-theoretic asymptotes are achieved, and optimizes the transmit power over time in order to maximize the throughput. Another branch of recent literature aims to understand the fundamental capacity limits, i.e. information-theoretic capacities, of energy harvesting links under smaller scale dynamics, considering energy harvests at the channel use level. This branch necessitates a deeper look at the coding and transmission schemes in the physical layer, and ultimately aims to develop an information theory of energy harvesting communications, akin to Shannon's development of an information theory for average power constrained communications. In this introductory article, we survey recent results in this branch and point to open problems that could be of interest to a broad set of researchers in the fields of communication theory, information theory, signal processing, and networking. In particular, we review capacities of energy harvesting links with infinite-sized, finitesized, and no batteries at the transmitter.

Data modeling for the virtual observatory

Abstract The data modeling effort has played a key role in the Virtual Observatory project, and contributed to the effort to build a common reference framework to describe the necessary information attached to astronomical data: the metadata. Such metadata describe the observing parameters and characterize and qualify the observed measurements. These pieces of information are produced and stored in project archives. Standardizing a homogeneous representation of metadata allows uniform discovery and use of the data in the Virtual Observatory infrastructure. This paper describes the context of data modeling in the VO architecture and shows how data models support requirements on the data access layer and for applications development. How the modeling process has been undertaken is explained with a short overview of the different data models. We also discuss in some detail the lessons learned in this modeling and standardization effort.

A New ETL Approach Based on Data Virtualization

ETL (Extract-Transform-Load) usually includes three phases: extraction, transformation, and loading. In building data warehouse, it plays the role of data injection and is the most time-consuming activity. Thus it is necessary to improve the performance of ETL. In this paper, a new ETL approach, TEL (Transform-Extract-Load) is proposed. The TEL approach applies virtual tables to realize the transformation stage before extraction stage and loading stage, without data staging area or staging database which stores raw data extracted from each of the disparate source data systems. The TEL approach reduces the data transmission load, and improves the performance of query from access layers. Experimental results based on our proposed benchmarks show that the TEL approach is feasible and practical.

A Transport Layer Protocol for Uplink WiMAX Video Streaming

There are many ways to improve unreliable datagram protocol (UDP) for video streaming applications. One of them is by using negative acknowledgement (NACK). This paper proposed UDP enhancement by using both NACK-based retransmission and medium access (MAC) layer support for uplink video streaming application in WiMAX networks. Mathematical models and analysis are presented to compare protocol performances in relation to delay and packet loss. The analysis is then confirmed through simulations using the ns-2 simulator. The results show that by reducing the number of NACK packets within one video frame and utilizing MAC support could reduce effective loss rate and delay significantly.

Study of MAC routing in the BPLC P1901 access network: fixed vs. adaptive approach

In this paper we propose an improved adaptive media access (MAC) layer routing algorithm for the broadband power line communication (BPLC) access network founded on the fixed basic approach routing algorithm, which is integrated within the IEEE P1901 standard. The proposed adaptive algorithm incorporates a new dynamically scaled threshold for the selection of the next hop station based on the information from the physical layer. Furthermore, the procedures for the route and the time allocation modifications during the connection setup and later adjustments are developed. Simulation of the new adaptive and existing fixed routing algorithm is performed on the model of a realistic BPLC network using the OMNeT++-based BPLC cross-layer simulator BPlcSim. The simulation results showed that the adaptive routing algorithm outperforms the fixed routing in all aspects, since each station can perform routing functions and make the selection of the most reliable next hop station.

Vulnerability of the Process Communication Model in Bittorrent Protocol

BitTorrent is the most extensively used protocol in peer-to-peer systems. Its clients are widely spread worldwide and account for a large fraction of today’s Internet traffic. This paper will discuss potential attack that exploits a certain vulnerability of BitTorrent based systems. Code injection refers to force a code – which may be malicious - to run inside another benign code, by inserting it into known process name or process ID. Operating systems supply API functions that can be used by third party to inject a few lines of malicious code inside the original running process, which can effectively damage or harm user resources. Ethernet is the most common internetwork layer for Local Area Networks; the shared medium of LAN enables all users on the same broadcasting domain to listen to all exchanged packets through the network (promiscuous mode), so any adversary can easily perform a simple packet sniffing process on the medium access layer of the network. By capturing and analyzing the sent packets from the P2P application, an adversary can use the revealed process ID by BitTorrent protocol to start the code injection action. So the adversary will be able to seize more machines from the network. Controlled machines can be used to perform many attacks. The study revealed that any adversary can exploit the vulnerability of the process communication model used in P2P by injecting any malicious process inside the BitTorrent application itself exposed by sniffing the exchanged BitTorrent packets through LAN.

A multidimensional information model for managing construction information

With the increasing scale of construction projects, coupled with their complexity, information management in the construction process becomes more complex and trivial. Moreover, the communication among project participants is hindered by the large amount and scattered structure of the information involved in the construction process. Most present studies on the information management of construction focus on the special needs of construction sectors rather than a total information integration of general aspects. This paper presents a multidimensional information model that combines Workflow, Work Breakdown Structures (WBS) and Time factor to manage information based on process control. Unlike previous researches, the present work puts emphasis on process control to enhance the communication process. The proposed information model uses the WBS and Time factor to manage information in the spatial and time dimension and control the process information of each work package during project execution through the workflow technology. In order to test the proposed information model, a web-based project management system (WPMS) was developed using the three layer architecture. The system structure realizes the invisible logic of the information model through the business logic layer and the data access layer. The system has been applied to a construction project of an underground cavern group in a hydropower project in the southwest of China. The application has shown that it achieves managing information based on process control and provides structured information.

Framework Structure on English Resource Library in Networked Environment

With the popularity of the English application, English resources are increasingly important; this paper studies the framework structure for the difficult problems in the English resource library construction. First, it designed the framework structure model of English resource library, and then each layer of the model is described in detail. Among them, the resources and the functional layer includes all resource information in English resource library and user’s operating functions for resources; system layer, including business logic layer and data access layer, to achieve the high cohesion and low coupling of development, maintenance, deployment, expansion; the user level, including teachers users, student users, administrators and other users, each user has different permissions, you can use the different functions. Contents of this paper provide theoretical support and technical support for building English resource library construction.

Design and Implementation of Embedded Database Based on File System – The Design and Implementation of EDB

The architecture of the system is divided into some modules according to the operating level: interface layer, the database engine layer, and data access layer, database maintenance module and data storage module. This paper discusses in detail the data definition design and the important function of EDB and realizes the EDB management implementation details. The paper introduce in details the EDB system architecture, the design of physical storage structure and basic table structure. Through the actual use, the database system is suitable for embedded systems with limited resources, has good portability.

Voice Quality Analysis for Software based Traffic Separation at the Access Layer of Hierarchical Design Model

In many countries including Tanzania access network is still predominantly made up of the copper cable or point to point wireless connections. This has kept the network in large proportions passive, inflexible and relatively unreliable. Software based traffic separation at the access layer is a technique that is used to reduce the number of physical links to customer premises. This paper performs quality analysis for voice transmitted through such links (i.e. logical links) and it is observed that there is no major difference as to when dedicated physical links are used. General Terms Voice quality, Traffic separation, Hierarchical design model

Ubiquitous WSN for Healthcare: Recent Advances and Future Prospects

Wireless sensor networks (WSNs) have witnessed rapid advancement in medical applications from real-time telemonitoring and computer-assisted rehabilitation to emergency response systems. In this paper, we present the state-of-the-art research from the ubiquity perspective, and discuss the insights as well as vision of future directions in WSN-based healthcare systems. First, we propose a novel tiered architecture that can be generally applied to WSN-based healthcare systems. Then, we analyze the IEEE 802 series standards in the access layer on their capabilities in setting up WSNs for healthcare. We also explore some of the up-to-date work in the application layer, mostly on the smartphone platforms. Furthermore, in order to develop and integrate effective ubiquitous sensing for healthcare (USH), we highlight four important design goals (i.e., proactiveness, transparency, awareness, and trustworthiness) that should be taken into account in future systems.

XTM-based Metadata Exploration and Retrieval: The History of Spanish Civil Engineering Project

This paper describes the History of Spanish Civil Engineering Project. The purpose of this project is to create a web repository where users can access the description of archival materials related to Spanish civil engineers. Personal fonds are being added to this repository based on the initial work completed on the Carlos Fernández Casado and E. Torroja pesonal fonds. From a technical perspective, the project makes use of the RDF and XTM standards to automatically generate topic maps that can be used to browse the different fonds and collections.The system architecture keeps the navigational aids (based on XTM) independent of the descriptive metadata used as a source. The XTM topic map works as an intermediate layer to ensure uniform access to information resources spread across different servers. The paper discusses the differences between RDF and XTM, and how these standards are being applied in the generation of the access layer.

Analysis and Design on Sports Meeting Information System

In the course of sports meeting, managing large amounts of data by hand is very difficult, the computer will be used in sports meeting management, accuracy and efficiency of data processing provides an important safeguard, in this paper, the sports meeting information system analysis and design. First, workflow analysis, pointed out the modern sports meeting work flow, as the basis for the next software development work; Then, functional requirements analysis, modeling example through interaction with each participant to clarify the main functions of the system implementation; Finally, the framework structure design, design the SSH three layer frame structure based on J2EE, for the presentation layer, business logic, data access layer is described in detail. To study the content of this article is based, easy to construct, easy maintenance, good reusability Web systems.

Research and Implementation of SOA Application Based on Component Technology

Taking command of an organization working in the field of research background, first thought SOA architecture provides a brief introduction to analyze the definition of SOA architecture, composition and basic characteristics; then the concept of software reuse and component technology, classification and component specification also gives a brief introduction, and compare the similarities and differences between SOA and component technology. Finally, after the adoption of principles and in-depth analysis of the characteristics and advantages of the above-mentioned technical theory, the actual project - designed on the basis of command system, proposed the use of layered application architecture based on SOA technology components for the overall system implementation. Explore how to design resource layer, component layer, services, processes and access layers to build a good architecture, intended to achieve efficient and loose coupling between the level of purpose, and build applications and develop a multi-command system quickly.

Internet of Things and BOM-Based Life Cycle Assessment of Energy-Saving and Emission-Reduction of Products

Energy-saving and emission-reduction (ESER), carbon footprint, carbon labeling, and carbon trading have attracted much attention recently due to severe environmental challenges. One key technology for implementing the above concepts is how to realize the effective quantitative evaluation of ESER. In this paper, the existing ESER evaluation technology and systems are summarized first. It is found that the existing ESER evaluation technology and systems are almost isolated from the existing enterprise information systems, such as enterprise resource planning (ERP), product data management (PDM), and customer relationship management (CRM), which results in the expanding of the enterprise information islands. In order to address this problem, a new method for ESER life cycle assessment (LCA) based on Internet of Things (IoT) and bill of material (BOM) is proposed in this paper. A four-layered structure (i.e., perception access layer, data layer, service layer, and application layer) ESER LCA system based on IoT and BOM is designed and presented, as well as the key technologies and the functions in each layer. A prototype application system is developed to validate the proposed method. The main contributions of the proposed method are: 1) facilitate real-time intelligent perception, and the collection of energy consumption and environmental impact data generated in the entire life cycle of manufacturing by using IoT technologies; and 2) realize effective data integration between the ESER evaluation system and the existing enterprise information systems based on BOM.