Hexachlorinated Boron(III) Subphthalocyanine as Acceptor for Organic Photovoltaics: A Brief Overview

A boron(III) complex of peripherally hexachlorinated subphthalocyanine, Cl6SubPc is a very promising small-molecule acceptor for application in organic photovoltaics. In this chapter the recent experimental results in the field are compared, and a critical review is given of the published works on the solar cells with the planar or bulk heterojunction architectures. The thin film properties of Cl6SubPc are also considered. The approaches to the further modification of the molecular structure of boron(III) subphthalocyanine-type compounds for the enhancement of their photoelectrical properties are discussed

ADAPTIVE POWER MANAGEMENT FOR COMPUTERS AND MOBILE DEVICES

Power consumption has become a major concern in the design of computing systems today. High power consumption increases cooling cost, degrades the system reliability and also reduces the battery life in portable devices. Modern computing/communication devices support multiple power modes which enable power and performance tradeoff. Dynamic power management (DPM), dynamic voltage and frequency scaling (DVFS), and dynamic task migration for workload consolidation are system level power reduction techniques widely used during runtime. In the first part of the dissertation, we concentrate on the dynamic power management of the personal computer and server platform where the DPM, DVFS and task migrations techniques are proved to be highly effective. A hierarchical energy management framework is assumed, where task migration is applied at the upper level to improve server utilization and energy efficiency, and DPM/DVFS is applied at the lower level to manage the power mode of individual processor. This work focuses on estimating the performance impact of workload consolidation and searching for optimal DPM/DVFS that adapts to the changing workload. Machine learning based modeling and reinforcement learning based policy optimization techniques are investigated. Mobile computing has been weaved into everyday lives to a great extend in recent years. Compared to traditional personal computer and server environment, the mobile computing environment is obviously more context-rich and the usage of mobile computing device is clearly imprinted with user\u27s personal signature. The ability to learn such signature enables immense potential in workload prediction and energy or battery life management. In the second part of the dissertation, we present two mobile device power management techniques which take advantage of the context-rich characteristics of mobile platform and make adaptive energy management decisions based on different user behavior. We firstly investigate the user battery usage behavior modeling and apply the model directly for battery energy management. The first technique aims at maximizing the quality of service (QoS) while keeping the risk of battery depletion below a given threshold. The second technique is an user-aware streaming strategies for energy efficient smartphone video playback applications (e.g. YouTube) that minimizes the sleep and wake penalty of cellular module and at the same time avoid the energy waste from excessive downloading. Runtime power and thermal management has attracted substantial interests in multi-core distributed embedded systems. Fast performance evaluation is an essential step in the research of distributed power and thermal management. In last part of the dissertation, we present an FPGA based emulator of multi-core distributed embedded system designed to support the research in runtime power/thermal management. Hardware and software supports are provided to carry out basic power/thermal management actions including inter-core or inter-FPGA communications, runtime temperature monitoring and dynamic frequency scaling

A Coordination Model and Framework for Developing Distributed Mobile Applications

How to coordinate multiple devices to work together as a single application is one of the most important challenges for building a distributed mobile application. Mobile devices play important roles in daily life and resolving this challenge is vital. Many coordination models have already been developed to support the implementation of parallel applications, and LIME (Linda In a Mobile Environment) is the most popular member. This thesis evaluates and analyzes the advantages and disadvantages of the LIME, and its predecessor Linda coordination model. This thesis proposes a new coordination model that focuses on overcoming the drawbacks of LIME and Linda. The new coordination model leverages the features of consistent hashing in order to obtain better coordination performance. Additionally, this new coordination model utilizes the idea of replica mechanism to guarantee data integrity. A cross-platform coordination framework, based on the new coordination model, is presented by this thesis in order to facilitate and simplify the development of distributed mobile applications. This framework aims to be robust and high-performance, supporting not only powerful devices such as smartphones but also constrained devices, which includes IoT sensors. The framework utilizes many advanced concepts and technologies such as CoAP protocol, P2P networking, Wi-Fi Direct, and Bluetooth Low Energy to achieve the goals of high-performance and fault-tolerance. Six experiments have been done to test the coordination model and framework from di erent aspects including bandwidth, throughput, packages per second, hit rate, and data distribution. Results of the experiments demonstrate that the proposed coordination model and framework meet the requirements of high-performance and fault-tolerance

Techniques for the realization of ultrareliable spaceborne computers Interim scientific report

Error-free ultrareliable spaceborne computer

Low-power emerging memristive designs towards secure hardware systems for applications in internet of things

Emerging memristive devices offer enormous advantages for applications such as non-volatile memories and in-memory computing (IMC), but there is a rising interest in using memristive technologies for security applications in the era of internet of things (IoT). In this review article, for achieving secure hardware systems in IoT, low-power design techniques based on emerging memristive technology for hardware security primitives/systems are presented. By reviewing the state-of-the-art in three highlighted memristive application areas, i.e. memristive non-volatile memory, memristive reconfigurable logic computing and memristive artificial intelligent computing, their application-level impacts on the novel implementations of secret key generation, crypto functions and machine learning attacks are explored, respectively. For the low-power security applications in IoT, it is essential to understand how to best realize cryptographic circuitry using memristive circuitries, and to assess the implications of memristive crypto implementations on security and to develop novel computing paradigms that will enhance their security. This review article aims to help researchers to explore security solutions, to analyze new possible threats and to develop corresponding protections for the secure hardware systems based on low-cost memristive circuit designs