Energy-efficient instruction set architecture for CMOS microprocessors

A stack-based instruction set which includes two-operand, one-operand and zero-operand instructions is proposed, and is shown to produce a more compact code and fewer instructions for evaluating assignment statements than one-operand and zero-operand stack instruction sets. If this instruction set is then extended to include two-operand memory-to-memory instructions, the combined instruction set also produces more compact code than a simple memory-to-memory instruction set, for a set of typical assignment statements weighed by the frequency of their occurrence in real programs. Finally various alternatives for optimizing the proposed instruction set are discussed.

Around 1970 Intel discovered it could put 2,000 transistorsor perhaps a few moreon a single NMOS chip. In retrospect, this may be said to mark the beginning of very large-scale integration (VLSI), ...

The Wake-Up Radio (WUR) system enables battery-powered sensors to stay in low-power sleep mode while listening for a wake-up signal (WUS). Upon receiving a WUS, the sensor activates its primary communication radio (PCR) to transmit data, reducing idle listening and retransmissions. However, polling data inefficiently can waste energy and storage, especially when updates provide little meaningful information. Due to the sink’s limited knowledge of node-side processes, accurately selecting nodes that provide valuable updates is challenging. We propose a Whittle Index AoII (WAoII) policy with state estimation techniques, allowing optimal node selection without assuming transition probabilities. Experimental results show WAoII with state estimation achieves near-optimal performance, reducing packet transmissions by up to 70% while enabling accurate data pattern reconstruction an aspect overlooked by other methods. These findings highlight WAoII with state estimation as an effective approach for polling data from wireless sensor nodes (WSNs) with WUR, maximising the value of information (VoI) while minimising energy and storage demands.

In wireless sensor networks, Energy efficiency is the most important performance target to prolong the networks lifetime. As the idle listening of sensor nodes result in primary energy waste, many typical MAC protocols are designed to save power by placing the radio in the low-power sleep mode, however, such schemes can lead to sleep latency problems in multi-hop transmissions. This paper analyses the sleep latency, and proposes a low- latency MAC protocol (LLMAC), which uses asynchrony message package for frame schedule between neighbor nodes instead of SYNC package in S-MAC, and brings in the stagger active schedule mechanism to maintain the data forwarding transmission. Simulation results show much better performance of the latency control compared with the existing schemes.

9 - Principle Eight: Utilize Energy-Efficient Technology

Previous work on routing in MANETs has resulted in numerous routing protocols that aim at satisfying constraints such as minimum hop or low energy. Existing routing protocols often fail to discover stable routes between source and sink when route availability is transient, i.e., due to mobile devices switching their network cards into low-power sleep modes whenever no communication is taking place. In this paper, we introduce a stability aware dynamic source routing protocol (SA-DSR) that is capable of predicting the stability (i.e., expiration time) of multiple routes. SA-DSR then selects the route that minimizes hop count while staying available for the expected duration of packet transmission. Comparisons of SA-DSR to the original DSR (Dynamic Source Routing) protocol indicate a significant (up to 60%) increase in route discovery success rate with comparable route establishment and maintenance overheads.

In wireless sensor networks, efficient usage of energy helps in improving the network lifetime. As the battery of a sensor node, in most cases, cannot be recharged or replaced after the deployment of the sensors, energy management becomes a critical issue in such networks. In order to detect an event, a sensor network spends majority of the time in monitoring its environment, during which a significant amount of energy can be saved by placing the radio in the low-power sleep mode. This can be achieved by using a dual frequency radio setup. However, such energy saving protocols increase the latency encountered in setting up a multihop path. We, in this paper, propose a reservation scheme, latency minimized energy efficient MAC protocol (LEEM), which is a novel hop-ahead reservation scheme in a dual frequency radio to minimize the latency in the multihop path data transmission by reserving the next hop's channel a priori. Thus, in a multihop sensor network, a packet can be forwarded to the next hop, as soon as it is received by a sensor node, which helps in eliminating the delay incurred for setting up the path. Simulation results show that LEEM consumes lesser power and reduces end-to-end latency by around 50% than that of the existing schemes

In data gathering wireless sensor network applications, data correlation among the sensor nodes have been utilized to extend network lifetimes. It has been shown that the data correlation also exists between nodes that are far away, contrary to the assumption that correlation decreases as a function of distance. Therefore, it is possible to group the nodes based on the correlation among their data regardless of their location. Given that data from one active node per group is sufficient to reconstruct the sensed data for the remaining sensor nodes, most of the nodes can be kept in low-power sleep mode. However, only few active nodes will usually create a disconnected network, and hence failing the purpose of the deployment. In this paper we formalize this problem, referred to as Sleep-route, of selecting the minimum number of connected active nodes that are sufficient to predict the sensed data for remaining sleeping nodes with high accuracy. We prove that the problem is NP-hard. Thus, we develop a greedy algorithm, Sleep-route heuristic that provides near-optimal solutions. Using Contiki-based simulations, we show that our scheme can extend network lifetime up to 42% as compared to the state-of-the-art solutions.

The next frontier for communications networks: power management

A remotely monitored system to measure patient’s blood pressure (BP) is described. The data are transferred to a central monitoring station using a wireless sensor network for display and storage. One mote was interfaced to the BP monitor for data acquisition and the others were utilized to route the BP data to the monitoring station. A user friendly graphical user interface (GUI) is designed for monitoring current and past measurements for all observed patients. Test results indicated high accuracy in BP measurements. Power consumption by the BP monitor interfaced mote was minimized by forcing it into a low-power sleep mode when not in use.KeywordsWireless sensor networkBlood pressure monitor (BPM)Base station

This paper describes an energy-efficient SAR ADC for ultra-low power applications. The asynchronous 2 b/step scheme halves both conversion time and DAC/digital circuit's switching activities and hence likewise reduces static and dynamic energy consumption. A low-power sleep mode is engaged at the end of each clock period. The technical contributions of this work include: 1) an innovative 2 b/step reference scheme based on a hybrid R-2R/C-3C DAC to minimize DAC hardware, 2) an interpolation-assisted time-domain 2 b comparison scheme that saves 33% in comparator circuitry, and 3) a dual-edge-comparison mechanism that reduces the time-domain comparator's (TDC) switching activities by 50%. All these techniques help reduce circuit overhead and overall energy consumption. The prototype ADC was fabricated in 180 nm CMOS process with an active area of 0.103 mm 2 . With a single 0.6 V supply and reference, the ADC achieves an ENoB of 9.2 bits and a FoM of 6.7 fJ/conversion-step while sampling at 100-kS/s.

Traditional portfolio management tools and methods are challenging for software companies that use agile and lean approaches, because of the complex pre‐planning activities required. In this paper, traditional portfolio management tools and methods that have been conventionally used in industry and presented in literature are reviewed. Findings concerning their use in agile and lean software companies are investigated, on the basis of the literature review and semi‐structured interviews conducted in 7 agile and lean software companies in Finland. The findings indicate that the studied companies do not use traditional portfolio management tools and methods in their entirety. The software companies adapted suitable components from traditional portfolio management tools and methods into their practices. They also apply new tools and methods to manage their portfolios of offerings, to cope with the dynamics required by agile and lean methods. The companies' emphasis is on using tools to facilitate immediate feedback from customers, to assess the value of offerings in their portfolio. The results showed a growing interest in using Kanban at the portfolio level to provide a visual overview of offerings.

Energy efficiency is a central challenge in sensor networks, and the radio is a major contributor to overall energy node consumption. Current energy-efficient MAC protocols for sensor networks use a fixed low-power radio mode for putting the radio to sleep. Fixed low-power modes involve an inherent trade-off: deep sleep modes have low current draw and high energy cost and latency for switching the radio to active mode, while light sleep modes have quick and inexpensive switching to active mode with a higher current draw. This paper proposes adaptive radio low-power sleep modes based on current traffic conditions in the network. It first introduces a comprehensive node energy model, which includes energy components for radio switching, transmission, reception, listening, and sleeping, as well as the often disregarded microcontroller energy component for determining the optimal sleep mode and MAC protocol to use for given traffic scenarios. The model is then used for evaluating the energy-related performance of our recently proposed RFID impulse protocol enhanced with adaptive low-power modes, and comparing it against BMAC and IEEE 802.15.4, for both MicaZ and TelosB platforms under varying data rates. The comparative analysis confirms that RFID impulse with adaptive low-power modes provides up to 20 times lower energy consumption than IEEE 802.15.4 in low traffic scenario. The evaluation also yields the optimal settings of low-power modes on the basis of data rates for each node platform, and provides guidelines and a simple algorithm for the selection of appropriate MAC protocol, low-power mode, and node platform for a given set of traffic requirements of a sensor network application.

The traditional construction structure construction quality management method ignores the mutual influence of various factors, divides the construction period into relatively independent links, and conducts quality management separately, resulting in poor management effectiveness of the traditional management method. In order to solve the above problems and improve the feasibility of the quality management method, the green construction engineering structure quality management method based on the BIM model is studied. Analyze the factors that affect the construction quality in the green building construction project, and determine the correlation between the factors. Use the BIM model to improve the three-dimensional spatial information of the building, and combine the PDCA quality management system to achieve the management of the construction quality of the project. The experimental results show that, compared with the traditional construction quality management method, the quality management method based on BIM model is more feasible and effective.

In this project, we design an instruction set architecture for a proposed hybrid continuous-discrete computer (HCDC) chip. The ISA harnesses the microarchitectural features and analog circuitry provided in the hardware. We describe the workloads that are suitable for the HCDC architecture. The underlying microarchitecture for the HCDC chip, including its controllers, datapaths, and interfaces to analog and digital functional units are specified in detail. We live in a world that is continuous: our eyes see scenes defined by continuous curves and intensities of colors, hear sounds formed by continuously varying pressure waves, and we sense velocity and temperature as continuous signals. In contrast, current computers operate in a discrete world, despite the continuous nature of the world at the scale our senses perceive. We finely divide time and space into quanta in order to model the real world on our digital computers. The inherent costs of digital computing have been acceptable because of digital computers exponential growth in computing power relative to energy consumption and size. However, as scaling in digital computers comes to an end, we must explore alternatives to digital, discrete computing.