How migrating 0.0001% of address space saves 12% of energy in hybrid storage

We present a simple, operating-\ud system independent method to reduce the num-\ud ber of seek operations and consequently reduce\ud the energy consumption of a hybrid storage\ud device consisting of a hard disk and a flash\ud memory. Trace-driven simulations show that\ud migrating a tiny amount of the address space\ud (0.0001%) from disk to flash already results\ud in a significant storage energy reduction (12%)\ud at virtually no extra cost. We show that the\ud amount of energy saving depends on which part\ud of the address space is migrated, and we present\ud two indicators for this, namely sequentiality and\ud request frequency. Our simulations show that\ud both are suitable as criterion for energy-saving\ud file placement methods in hybrid storage. We\ud address potential wear problems in the flash\ud subsystem by presenting a simple way to pro-\ud long its expected lifetime.\u

ERP implementation for an administrative agency as a corporative frontend and an e-commerce smartphone app

This document contains all the descriptions, arguments and demonstrations of the researches, analysis, reasoning, designs and tasks performed to achieve the requirement to technologically evolve an managing agency in a way that, through a solution that requires a reduced investment, makes possible to arrange a business management tool with e-commerce and also a mobile application that allows access and consultation of mentioned tool. The first part of the document describes the scenario in order to contextualize the project and introduces ERP (Enterprise Resources Planning). In the second part, a deep research of ERP market products is carried out, identifying the strengths and weaknesses of each one of the products in order to finish with the choice of the most suitable product for the scenario proposed in the project. A third part of the document describes the installation process of the selected product carried out based on the use of Dockers, as well as the configurations and customizations that they make on the selected ERP. A description of the installation and configuration of additional modules is also made, necessary to achieve the agreed scope of the project. In a fourth part of the thesis, the process of creating an iOS and Android App that connects to the selected ERP database is described. The process begins with the design of the App. Once designed, it is explained the process of study and documentation of technologies to choose the technology stack that allows making an application robust and contemporary without use of licensing. After choosing the technologies to use there are explained the dependencies and needs to install runtime enviornments prior to the start of coding. Later, it describes how the code of the App has been raised and developed. The compilation and verification mechanisms are indicated in continuation. And finally, it is showed the result of the development of the App once distributed. Finally, a chapter for the conclusions analyzes the difficulties encountered during the project and the achievements, analyzing what has been learned during the development of this project

Performance evaluation of 5G millimeter-wave cellular access networks using a capacity-based network deployment tool

The next fifth generation (5G) of wireless communication networks comes with a set of new features to satisfy the demand of data-intensive applications: millimeter-wave frequencies, massive antenna arrays, beamforming, dense cells, and so forth. In this paper, we investigate the use of beamforming techniques through various architectures and evaluate the performance of 5G wireless access networks, using a capacity-based network deployment tool. This tool is proposed and applied to a realistic area in Ghent, Belgium, to simulate realistic 5G networks that respond to the instantaneous bit rate required by the active users. The results show that, with beamforming, 5G networks require almost 15% more base stations and 4 times less power to provide more capacity to the users and the same coverage performances, in comparison with the 4G reference network. Moreover, they are 3 times more energy efficient than the 4G network and the hybrid beamforming architecture appears to be a suitable architecture for beamforming to be considered when designing a 5G cellular network

Distributed Storage in Mobile Wireless Networks with Device-to-Device Communication

We consider the use of distributed storage (DS) to reduce the communication cost of content delivery in wireless networks. Content is stored (cached) in a number of mobile devices using an erasure correcting code. Users retrieve content from other devices using device-to-device communication or from the base station (BS), at the expense of higher communication cost. We address the repair problem when a device storing data leaves the cell. We introduce a repair scheduling where repair is performed periodically and derive analytical expressions for the overall communication cost of content download and data repair as a function of the repair interval. The derived expressions are then used to evaluate the communication cost entailed by DS using several erasure correcting codes. Our results show that DS can reduce the communication cost with respect to the case where content is downloaded only from the BS, provided that repairs are performed frequently enough. If devices storing content arrive to the cell, the communication cost using DS is further reduced and, for large enough arrival rate, it is always beneficial. Interestingly, we show that MDS codes, which do not perform well for classical DS, can yield a low overall communication cost in wireless DS.Comment: After final editing for publication in TCO