Energy Efficiency in the ICT - Profiling Power Consumption in Desktop Computer Systems

Energy awareness in the ICT has become an important issue. Focusing on software, recent work suggested the existence of a relationship between power consumption, software configuration and usage patterns in computer systems. The aim of this work was collecting and analysing power consumption data of general-purpose computer systems, simulating common usage scenarios, in order to extract a power consumption profile for each scenario. We selected two desktop systems of different generations as test machines. Meanwhile, we developed 11 usage scenarios, and conducted several test runs of them, collecting power consumption data by means of a power meter. Our analysis resulted in an estimation of a power consumption value for each scenario and software application used, obtaining that each single scenario introduced an overhead from 2 to 11 Watts, which corresponds to a percentage increase that can reach up to 20% on recent and more powerful systems. We determined that software and its usage patterns impact consistently on the power consumption of computer systems. Further work will be devoted to evaluate how power consumption is affected by the usage of specific system resource

Lyapunov functions for a non-linear model of the X-ray bursting of the microquasar GRS 1915+105

This paper introduces a biparametric family of Lyapunov functions for a non-linear mathematical model based on the FitzHugh-Nagumo equations able to reproduce some main features of the X-ray bursting behaviour exhibited by the microquasar GRS 1915+105. These functions are useful to investigate the properties of equilibrium points and allow us to demonstrate a theorem on the global stability. The transition between bursting and stable behaviour is also analyzed.Comment: Published on International Journal of Non-Linear Mechanics, vol. 88, pp. 142-14

A highly efficient simulation technique for piezoelectric energy harvesters

This paper presents a new numerical technique which is aimed at obtaining fast and accurate simulations of piezoelectric beams, used in inertial energy harvesting MEMS. The execution of numerical analyses is greatly important in order to predict the actual behaviour of MEMS device and to carry out the optimization process on the basis of Design of Experiments (DOE) techniques. In this paper, a refined, yet simple, model is proposed with reference to the multi-physics problem of piezoelectric energy harvesting by means of laminate cantilevers. The proposed model is calibrated and validated with reference to 3D finite element analyses

Numerical and experimental evaluation of the magnetic interaction for frequency up-conversion in piezoelectric vibration energy harvesters

The purpose of this work is to improve the modelling process for the application of permanent magnets in a frequency up-conversion (FuC) mechanism for piezoelectric energy harvesters. More specifically, the aim is to avoid the burdensome finite element analyses (FEA) in the framework of electromechanical devices design. The analytical calculations are compared with experimental tests conducted by an ad-hoc set up and with FEA. After investigations on the interaction, an application of FuC mechanism is proposed on a meso-scale case study in which a low frequency seismic mass (LFM) interacts non-linearly, due to magnetic field, with an high frequency piezoelectric vibration energy harvester (PVEH). Numerical simulations have been carried out in the time domain (step-by-step analysis) under a harmonic low-frequency input acceleration signal. The peculiar behavior, due to non-linear dynamics, is investigated in both the repulsive and the attractive configurations of the magnets. The results confirm the effectiveness of magnetic FuC and show that the repulsive case allows the device to recover a larger amount of energy than the attractive configuration

Strategi Pengembangan Agribisnis Komoditas Padi dalam Meningkatkan Ketahanan Pangan Kabupaten Jember

Tujuan dari penelitian ini adalah 1) menganalisis kekuatan, kelemahan, peluang dan ancaman untuk mengembangan komoditas padi dalam upaya meningkatkan ketahanan pangan; 2) melakukan analisis rumusan alternatif strategi yang tepat untuk pengembangan komoditas padi dalam upaya meningkatkan ketahanan pangan; 3) menentukan prioritas strategi yang seharusnya dipilih untuk pengembangan komoditas padi dalam upaya meningkatkan ketahanan pangan; 4) memberikan rekomendasi kebijakan yang harus dilakukan pemerintah pusat/ daerah untuk meningkatkan ketahanan pangan. Analisis SWOT digunakan untuk menentukan alternatif strategi yang dapat dilakukan pemerintah. Analisis QSPM berfungsi menentukan pilihan strategi prioritas dalam mengembangkan agribisnis padi di Kabupaten Jember. Metode deskriptif digunakan untuk menjelaskan studi kasus pada Dinas Pertanian Kabupaten Jember dengan sampel responden sebanyak 35 orang. Motivasi petani merupakan kekuatan utama yang dimiliki oleh pemerintah Kabupaten Jember. Kelemahan utama yang harus diperbaiki adalah kondisi finansial yang lemah. Peluang utama yang dimiliki adalah peningkatan permintaan beras dan ancaman utamanya berupa serangan organisme pengganggu tanaman. Alternatif strategi yang dapat dilakukan oleh pemerintah diantaranya: 1) Intensifikasi USAhatani padi, 2) Sinergi antara petani, pengusaha dan pemerintah, 3) Penguatan kebijakan pangan daerah yang berpihak kepada petani, 4) Revitalisasi sarana dan prasarana, 5) Diferensiasi produk. Strategi yang menjadi prioritas utama dalam penelitian ini adalah strategi intensifikasi USAha tani padi

On the application of piezolaminated composites to diaphragm micropumps

This paper deals with the numerical simulation of piezolaminated microplates adopted as actuators in micropumps. The performances of piezoelectric actuation is critically assessed by means of comparisons with devices based on the electrostatic force

Application of optimally-shaped phononic crystals to reduce anchor losses of MEMS resonators

This work is focused on the application of Phononic Crystals to reduce anchor losses of MEMS contour mode resonators. Anchor losses dominates the losses in these type of released resonators at low frequency and at low temperature. The use of phononic crystals, intended as finite-periodic distribution of holes in the anchor, is fully compatible with fabrication processes and moreover it is easy to implement. The numerical results obtained in this work show how the use of these crystals can significantly reduce the anchor losses: without the use of the crystal the Q-factor related to only anchor losses is 344, with the use of the crystal it can reach up to 105900

Profiling Power Consumption on Desktop Computer Systems

Background. Energy awareness in the ICT has become an important issue: ICT is both a key player in energy efficiency, and a power drainer. Focusing on software, recent work suggested the existence of a relationship between power consumption, software configuration and usage patterns in computer systems. Aim. The aim of this work was collecting and analysing power consumption data of a general-purpose computer system, simulating common usage scenarios, in order to extract a power consumption profile for each scenario. Methods. We selected a desktop system running Windows XP as a test machine. Meanwhile, we developed 11 usage scenarios, classified by their functionality, and automated by a GUI testing tool. Then, we conducted several test runs of the scenarios, collecting power consumption data by means of a power meter. Results. Our analysis resulted in an estimation of a power consumption value for each scenario and software application used, obtaining that each single scenario introduced an overhead from 2 to 11 Watts, corresponding to an increase of about 12%. Conclusions. We determined that software and its usage patterns impacts consistently on the power consumption of computer systems. Further work will be devoted to evaluate how power consumption is affected by the usage of specific system resources, like processors, disks, memory et