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Machine-to-machine communication is continuously extending to new application fields. Especially smart metering has the potential to become the first really large-scale M2M application. Although in the future distributed meter devices will be mainly connected via dedicated primary communication protocols, like ZigBee, Wireless
M-Bus or alike, a major percentage of all meters will be connected via point to point communication using GPRS or UMTS platforms. Thus, such meter devices have to be extremely cost and energy efficient, especially if the devices are battery based and powered several years by a single battery. This paper presents the development of an automated measurement unit for power and time, thus energy characteristics can be recorded. The measurement unit includes a hardware platform for the device
under test (DUT) and a database based software environment for a smooth execution and analysis of the measurements.
Die zunehmende Anzahl von Transistoren mit immer kleineren Strukturgrößen führt zu einer zunehmenden Leistungsaufnahme in modernen Prozessoren. Das gilt insbesondere für High-End Prozessoren, die mit einer hohen Taktfrequenz betrieben werden. Die aufgenommene Leistung wird in Wärme umgewandelt, die in einer Temperaturerhöhung der Prozessoren resultiert. Hohe Betriebstemperaturen verursachen u.a. eine verringerte Rechenleistung, eine kürzere Lebensdauer des Prozessors und höhere Leckströme. Aus diesen Gründen wird aktives, dynamisches thermisches Management immer wichtiger. Dieser Beitrag stellt eine Erweiterung zu dem Standard- Linux-Scheduler in der Kernel-Version 3.0 für eingebettete Systeme vor: einen PID-Regler, der unter Angabe einer Solltemperatur eine dynamische Frequenz- und Spannungsskalierung durchführt. Die Experimente auf dem Freescale LMX6 Quadcore-Prozessor zeigen, dass der PID-Regler die Betriebstemperatur des Prozessors an die Solltemperatur regeln kann. Er ist die Grundlage für eine in Zukunft zu entwickelnde prädiktive Regelung.
The integration of web servers into embedded systems offers a dividend at many levels. Operationally it can place industrial control, diagnostics and maintenance half a world away from the actual plant location – in fact anywhere with access to a reliable Internet connection.The ease and economy with which web-based architecture can integrate the activities of geographically diverse plant locations alone justifies use of the technology:The low cost and ubiquitous nature of Web Services components makes the case unassailable. Using public networks as a transmission layer for industrial architecture raises a legitimate concerns about security. But Virtual Private Networks can now deal effectively with the issue say Axel Sikora and Peter Brügger.
Chips nach dem Pizza-Prinzip
(1998)
Die Vision von der Integration komplexer Systeme auf einen Chip gibt es schon seit den frühesten Tagen der Halbleitertechnologie, als erstmals mehrere Einzeltransistoren gemeinsam auf einen Siliziumkristall gebannt wurden. Jetzt nimmt diese Vision immer mehr Gestalt an. Modulare Prozeßtechnologien gestatten die Realisierung von Systemen auf einen Chip.
Short range wireless networks (SRWN) are an important platform for an increasing number of applications. Apart from the pure communication benefit and other added values, e.g. ease-of-installation, support of mobility, high level of redundancy and reliability, wireless networks can bring in an important additional feature: localization. In many cases, the precision of ranging and localization is based on the measurement of Received Signal Strength (RSS) and is thus quite limited. Systems with time-of-flight measurements promise better performance. However, not many systems are commercially available for applications in Short Range Wireless Networks. One of the first available products uses Chirp Spread Spectrum technology with a symmetric two way ranging. This contribution examines the results, which were achieved with these products for real-life environments. Vehicle-based applications for active safety (eSafety) play a special role in those scenarios.
Ranging errors are inevitable in all local positioning systems, including those based on Time-of-Flight (ToF) technique. Results of experiments show that the major cause for these errors is a signal degradation from multipath propagation. This effect is especially critical in case of Non-Light-of-Sight (NLOS) conditions. This paper describes causes that affects ranging errors for nanoLOC™-TOF-technology and presents estimations for the probability density functions of such errors under different NLOS conditions. The provided estimations allow the improvement of the accuracy of the localization through the subsequent mitigation of the ranging errors from the measurements. Additionally, it is proposed to increase the number of cases of NLOS-conditions for the improvement of the accuracy.
Die Zukunft des Speichers
(2002)
Nachdem im ersten Teil dieses Artikels die Grundlagen und der gegenwärtige Status der Entwicklungen der ferroelektrischen RAMs im Mittelpunkt standen, sind im zweiten Teil jetzt ihre dualen Brüder, die magnetischen RAMs, an der Reihe. Darüber hinaus werden auch alternative Speicher-konzepte, wie Ovonics Unified Memory und polymerbasierte ferroelektrische RAMs beleuchtet.
Wireless systems continue to rapidly gain popularity. This is extremely true for data networks in the local and personal area, which are called WLAN and WPAN, respectively. However, most of those systems are working in the license-free industrial scientific medical (ISM) frequency bands, where neither resource planning nor bandwidth allocation can be guaranteed. To date, the most widespread systems in the 2.4 GHz ISM band are IEEE802.11 as stated in IEEE Std. 802-11 (1997) and Bluetooth, with ZigBee based in IEEE Std. 802.15.4 (2003) and IEEE802.15.4 as upcoming standards for short range wireless networks. In this paper we examine the mutual effects of these different communication standards. Measurements are performed with real-life equipment, in order to quantify coexistence issues.
Wireless systems continue to rapidly gain popularity. This is extremely true for data networks in the local and personal area, which are called WLAN and WPAN, respectively. However, most of those systems are working in the license-free industrial scientific medical (ISM) frequency bands, where neither resource planning nor bandwidth allocation can be guaranteed. To date, the most widespread systems in the 2.4 GHz ISM band are IEEE802.11 and Bluetooth, with ZigBee and IEEE802.15.4 as upcoming standards for short range wireless networks. In this paper we examine the mutual effects of these different communication standards. Measurements are performed with real-life equipment, in order to quantify coexistence issues.
Инерциальные МЭМС-датчики можно объединять в многокомпонентные модули для улучшения производительности. Для корректного слияния информации необходимо учитывать, что жестко связанные датчики при вращении испытывают разные ускорения из-за разного расстояния до центра вращения. Измерения МЭМС-датчиков включают как детерминированные ошибки, так и случайный шум. При комплексировании датчиков возможность улучшения точности зависит от того, насколько коррелируют ошибки измерений датчиков. Несмотря на то, что при слиянии информации обычно предполагается, что ошибки измерений разных датчиков независимы, теория статистического оценивания говорит о том, что при комбинировании датчиков одного типа более выгодным является наличие отрицательной корреляции. В статье представлены некоторые замечания относительно ком-плексирования датчиков, а также приведены предварительные результаты эксперимента по определению взаимной корреляции измерений инерциальных датчиков.