Current Issue : April - June Volume : 2014 Issue Number : 2 Articles : 4 Articles
There is a wide area of applications that use embedded systems, and the number of such systems keeps growing. The\r\nrequired functionality and complexity of embedded systems are also constantly increasing, and development of such\r\nproducts is becoming increasingly harder. This requires new thinking on the product development processes, and\r\none such emerging philosophy is the agile methods. These methods were created by the software engineering\r\ncommunity where they are commonly used. Since then, they have been adopted in embedded systems\r\ndevelopment; however, whether they can improve the embedded systems product development processes remains\r\nan open question. This study aims to bring forth what is known about agile methods in embedded systems\r\ndevelopment and to find out if agile practices are suitable in this domain and what evidence is there to support the\r\nfindings. We conducted a literature review and a mapping study to answer these questions. The scope of this study is\r\nnot only limited to embedded software development, but also to embedded hardware and integrated circuits. We\r\nhave found that agile methods can be used in the embedded domain, but the methods and practices need to be\r\nadapted to suit the more constrained field of embedded product development. Furthermore, the field of embedded\r\nproduct development has wide diversity of products with different needs and domain-specific problems so that no\r\nsingle method is applicable, but rather many methods and practices are needed for different situations....
An embedded telemetry unit for bone strain monitoring is presented. The telemetry unit is designed using\r\ncommercially available components to lower design time and manufacturing costs. The unit can read up to eight\r\nstrain gauges and measures 2.4 cmÃ?â?? 1.3 cmÃ?â?? 0.7 cm. The unit is powered from a small Li-polymer battery that can be\r\nrecharged wirelessly through tissue, making it suitable for implanted applications. The average current consumption\r\nof the telemetry unit is 1.9 mA while transmitting at a rate of 75 kps and at a sampling rate of 20 Hz. The telemetry unit\r\nalso features a power-down mode to minimize its power consumption when it is not in use. The telemetry unit\r\noperates in the 915-MHz ISM radio band. The unit was tested in an ex vivo setting with an ulna bone from a mouse\r\nand in a simulated in vivo setting with a phantom tissue. Bone strain data collected ex vivo shows that the telemetry\r\nunit can measure strain with an accuracy comparable to a more expensive benchtop data acquisition system....
This paper deals with dynamic voltage and frequency scaling (DVFS) in mobile multimedia services. The multimedia\r\nservices that consume a large amount of energy cannot be continuously used in mobile devices because of battery\r\nlimitation. The DVFS has been applied to multimedia services in previous studies. However, they have only\r\naddressed the issue of power saving and overlooked the fact that mobile multimedia services are sensitive to\r\ndelays. The proposed method is intended to apply DVFS to multimedia services considering potential delays.\r\nAnother problem with previous studies is that either separate devices have been employed or appropriate\r\nfrequency scaling values have been determined through complicated calculation processes to apply DVFS to\r\nmultimedia services. On the contrary, the proposed method determines appropriate frequency scaling values using\r\nthe characteristics of multimedia contents without employing any separate devices or undergoing complicated\r\ncalculation processes. This has the advantage of allowing DVFS to be applied to real-time multimedia content. The\r\npresent paper proposes a DVFS application method that divides multimedia services into video conferences, which\r\nare real-time services, and video streaming, which is a non-real-time service, and that reduces energy consumption\r\nin a simple manner while considering the constraints of service delays....
Radio frequency identification (RFID) is a technology enabling a contactless exchange of data. This technology\r\nfeatures the possibility to wirelessly transfer power to the transponder (opponent). HF-RFID is used in mobile devices\r\nlike smart phones and shows potential for applications like payment, identification, etc. Unfortunately, the needed\r\nfunctionality increases the battery drain of the device. As a countermeasure, power-management techniques are\r\nimplemented. However, these techniques commonly do not consider the whole system, which also consists of the\r\ncommunication to the transponder, to prevent wasting energy. One cross-system technique of reducing the wasted\r\nenergy is magnetic field strength scaling, which regulates the power transfer to the transponder. This article shows\r\nthree investigations made, regarding field strength scaling to prevent this wastage of energy. The results of one\r\ninvestigation, how to use field strength scaling at card detection phase in form of the PTF-Determinator method, is\r\ndescribed in detail. This method determines the Power Transfer Function (PTF) during run-time and scales the\r\nprovided power accordingly to save energy. As a case study the PTF-Determinator is integrated in an application to\r\nread digital business cards. The resulting power consumption and timing has been evaluated by simulation and\r\nmeasurement of a development platform for mobile phones. Furthermore, the impact of field strength scaling to the\r\nenergy consumption of a state of the art NFC-enhanced smart phone has been analyzed. The results of the case study\r\nshows that up to 26% less transmission energy (energy drain of NFC) is needed, if field strength scaling is applied\r\n(proofen by measurement). According to this result a smart phone�s battery drain (energy drain of the whole system)\r\ncan be decreased by up to 13% by using field strength scaling for this case study....
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