Model-driven interoperability: engineering heterogeneous IoT systems

Interoperability remains a significant burden to the developers of Internet of Things systems. This is because resources and APIs are dynamically composed; they are highly heterogeneous in terms of their underlying communication technologies, protocols and data formats, and interoperability tools remain limited to enforcing standards-based approaches. In this paper, we propose model-based engineering methods to reduce the development effort towards ensuring that complex software systems interoperate with one another. Lightweight interoperability models can be specified in order to monitor and test the execution of running software so that interoperability problems can be quickly identified, and solutions put in place. A graphical model editor and testing tool are also presented to highlight how a visual model improves upon textual specifications. We show using case-studies from the FIWARE Future Internet Service domain that the software framework can support non-expert developers to address interoperability challenges.     

Scalability in Global Mobile Information Systems (GloMo): Issues,Evaluation Methodology and Experiences

The GloMo (Global Mobile Information Systems) project¹ has focused on developing new wireless ad hoc networking technologies. These new technologies rely on a broad and varied set of techniques to help cope with the problems inherent in the wireless environment. One of the most critical design elements of all the various technologies is their applicability in large scale deployments. The main objective of our work is to develop and implement a simulation methodology to help evaluate the scalability of these new ad hoc networking technologies and gain some insight into the various aspects of ad hoc network performance scalability issues. To achieve that we have developed a scalability performance evaluation framework and plan, that spans all the various dimensions of scalability: size (number of nodes and density), traffic, operational environment (i.e. propagation models, terrain etc.), mobility. For demonstration purposes we have applied this process on a representative integrated protocol suite designed to provide communication services in mobile ad hoc wireless networks. The corresponding results of the two most critical aspects of scalability properties in tactical networks (i.e. network initialization time and traffic scalability) are also presented here, and demonstrate that a very extensive evaluation of the corresponding scalability metrics under a combination of the various scalability dimensions defined in this paper, is necessary in order to provide an in-depth analysis of the scalability properties in wireless mobile ad hoc networking environments.     

人机界面的演进

术语．“人机界面”突然间已进入技术领域专用词汇的行列,就其最基本词义而言,该术语不仅用于描述设备外观,更可以描述人与设备之间的交互过程。虽然这不是一个新概念,但是该技术能够彻底改变我们与电子设备交互方式的可用性,以及集成该技术的紧迫性表明用户对界面设计日益重视。     

实现无线设计过程的无缝协作

(上篇)在无线系统设计过程中依靠基于部门划分的方法,往往会给开发流程带来麻烦。使用系统级模型不仅可以解决诸多此类问题,而且能够大大改进设计流程。各家公司都在使用基于模型的设计,以整合不同的开发团队(例如,模拟和数字)和各个设计阶段(例如,设计和验证),从而获得巨大收益。     

适用于沉积工艺的真空技术

半导体生产中的薄膜沉积工艺通常对真空泵的要求很严格。在该工艺中高故障率和停机现象较为普遍。iH真空泵是特别为应付恶劣的薄膜工艺环境所设计。阐述了iH系列干泵在LPCVD氮化硅工艺应用中的成功表现。     

Performance and Modeling of the MWIR HgCdTe Electron Avalanche Photodiode

The operation of the mid-wave infrared (MWIR) HgCdTe cylindrical electron injection avalanche photodiode (e-APD) is described. The measured gain and excess noise factor are related to the collection region fill factor. A two-dimensional diffusion model calculates the time-dependent response and steady-state pixel point spread function for cylindrical diodes, and predicts bandwidths near 1 GHz for small geometries. A 2 μm diameter spot scan system was developed for point spread function and crosstalk measurements at 80 K. An electron diffusion length of 13.4 μm was extracted from spot scan data. Bandwidth data are shown that indicate bandwidths in excess of 300 MHz for small unit cells geometries. Dark current data, at high gain levels, indicate an effective gain normalized dark density count as low as 1000 counts/μs/cm² at an APD gain of 444. A junction doping profile was determined from capacitance–voltage data. Spectral response data shows a gain-independent characteristic.     

DVB-H移动数字电视综述

概述 自从20世纪40年代黑白广播电视问世以来,电视已走过了一个漫长的发展历程。我们经历了彩色电视与数字广播电视在画质方面的创新,以及在信号传输方式上的不断进步,如从有线到卫星再到HD等。每项新技术的推出都使电视的受欢迎程度与日俱增,并都能为观众带来更为丰富的节目内容。目前,电视正在迎来它的另一个全新的发展阶段：移动数字电视。     

Aerosol-jet-printed, high-speed, flexible thin-film transistor made using single-walled carbon nanotube solution

A high-purity, surfactant-free and stable SWCNT aqueous solution was prepared using a series of chemical and physical processes. The SWCNT solution has a very limited amount of carbonaceous impurities, if any, and a total metal content of well below 500 ppb. It is stable for months without the addition of surfactant. Such SWCNT aqueous solution enables ink-jet printing of the entire fast, flexible SWCNT-based field-effect thin-film transistor (FE-TFT) at room temperature without the engagement of any traditional dry or wet chemical processes used for fabricating silicon-based transistors. High-speed SWCNT-based flexible FE-TFTs were printed using Aerosol Jet^® printing technology. The printed flexible FE-TFTs were characterized to have a current ON-OFF ratio of greater than 130 with an operation frequency of greater than 5 GHz.