Integrated Flow-Cell Arrays (FCAs) represent a combination of integrated liquid cooling and on-chip power generation, converting chemical energy of the flowing electrolyte solutions to electrical energy. The FCA technology provides a promising way to address both heat removal and power delivery issues in 3D Multiprocessor Systems-on-Chips (MPSoCs). In this paper we motivate the benefits of FCA in 3D MPSoCs via a qualitative analysis and explore the capabilities of the proposed technology using our extended PowerCool simulator. PowerCool is a tool that performs combined compact thermal and electrochemical simulation of 3D MPSoCs with inter-tier FCA-based cooling and power generation. We validate our electrochemical model against experimental data obtained using a micro-scale FCA, and extend PowerCool with a compact thermal model (3D-ICE) and subthreshold leakage estimation. We show the sensitivity of the FCA cooling and power generation on the design-time (FCA geometry) and run-time (fluid inlet temperature, flow rate) parameters. Our results show that we can optimize the FCA to keep maximum chip temperature below 95 °C for an average chip power consumption of 50 W/cm2while generating up to 3.6 W per cm2of chip area.

In this paper, we report on a mobile-health intervention study for COPD patients. Mobile devices are used to continuously record relevant patient symptoms, such as lung function, cough intensity, sputum color, vital-signs and activity. Furthermore, behavioral support is provided by a bi-directional communication channel and virtual assistant communication. The goal is to train a predictive algorithm to prevent exacerbations and to provide personalized virtual coaching to improve medication adherence and activity level.

Wearables that continuously acquire vital and other medically relevant parameters facilitate treatment optimizations for individual patients and reduce the duration of hospitalizations - thus improving the patients' quality of life. To accomplish this, we demonstrate a scalable architecture that connects wearables through a hub to the cloud, combines edge and cloud computing to provide optimal user interaction, and allows analytics on multi-stream data from those connected devices.

The soaring demand for computing power in our digital information age has produced, as an undesirable side-effect, a surge in power consumption and heat density for Multiprocessors Systems-on-Chip (MPSoCs). The resulting temperature rise results in operating conditions that already preclude operating all the cores at maximum performance levels, in order to prevent system overheating and failures. With more power demands, MPSoCs will face a power delivery wall due to the reliability limitations of the underlying power delivery medium. Thus, state-of-the-art power and cooling delivery solutions are reaching their performance limits and it will no longer be possible to power up simultaneously all the available on-chip cores (situation known as dark silicon). In this paper we investigate a recently proposed disruptive approach to overcome the prevailing worst-case power and cooling provisioning paradigms for MPSoCs. This proposed approach integrates MPSoC with an on-chip microfluidic fuel cell network for joint cooling and power supply (i.e., localized power generation and delivery). By providing alternative means to power delivery integrated with cooling, MPSoCs are expected to gain in I/O connectivity. Based on this disruptive technology, we can envision the removal of the current limits of power delivery and heat dissipation in MPSoC designs, subsequently avoiding dark silicon and enabling a paradigm shift in future energy-proportional computing architecture designs.

Integrated microfluidic power generation and power delivery promises to be a disruptive packaging technology with the potential to combat dark silicon. It essentially consists of integrated microchannel-based electrochemical “flow cells” in a 2D/3D multiprocessor system-on-chip (MPSoC), that generate electricity to power up the entire or part of the chip, while also simultaneously acting as a high-efficiency microfluidic heat sink. Further development of this technology requires efficient modeling tools that would assess the efficacy of such solutions and help perform early-stage design space exploration. In this paper, we propose a compact mathematical model, called PowerCool, that performs electro-chemical modeling and simulation of integrated microfluidic power generation in MPSoCs. The accuracy of the model has been validated against fine-grained multiphysics simulations of flow cells in the COMSOL software that is unsuitable for EDA because of large simulation times. PowerCool model is demonstrated to be up to 425x times faster than COMSOL simulations while incurring a worst-case error of only 5%. Furthermore, the PowerCool model has been used to study and assess the efficacy of this technology for a test MPSoC.

Chip microscale liquid-cooling reduces thermal resistance and improves datacenter efficiency with higher coolant temperatures by eliminating chillers and allowing thermal energy re-use in cold climates. Liquid cooling enables an unprecedented density in future computers to a level similar to a human brain. This is mediated by a dense 3D architecture for interconnects, fluid cooling, and power delivery of energetic chemical compounds transported in the same fluid. Vertical integration improves memory proximity and electrochemical power delivery creating valuable space for communication. This strongly improves large system efficiency thereby allowing computers to grow beyond exa-scale.

New tendencies envisage 3D Multi-Processor System-On-Chip (MPSoC) design as a promising solution to keep increasing the performance of the next-generation high-performance computing (HPC) systems. However, as the power density of HPC systems increases with the arrival of 3D MPSoCs, supplying electrical power to the computing equipment and constantly removing the generated heat is rapidly becoming the dominant cost in any HPC facility. Thus, both power and thermal/cooling implications play a major role in the design of new HPC systems, given the energy constraints in our society. Therefore, EPFL, IBM and ETHZ have been working within the CMOSAIC Nano-Tera.ch program project in the last three years on the development of a holistic thermally-aware design. This paper presents the exploration in CMOSAIC of novel cooling technologies, as well as suitable thermal modeling and system-level design methods, which are all necessary to develop 3D MPSoCs with inter-tier liquid cooling systems. As a result, we develop energy-efficient run-time thermal control strategies to achieve energy-efficient cooling mechanisms to compress almost 1 Tera nano-sized functional units into one cubic centimeter with a 10 to 100 fold higher connectivity than otherwise possible. The proposed thermally-aware design paradigm includes exploring the synergies of hardware-, software- and mechanical-based thermal control techniques as a fundamental step to design 3D MPSoCs for HPC systems. More precisely, we target the use of inter-tier coolants ranging from liquid water and two-phase refrigerants to novel engineered environmentally friendly nano-fluids, as well as using specifically designed micro-channel arrangements, in combination with the use of dynamic thermal management at system-level to tune the flow rate of the coolant in each micro-channel to achieve thermally-balanced 3D-ICs. Our management strategy prevents the system from surpassing the given threshold temperature while achieving up to 67% reduction in cooling energy and up to 30% reduction in system-level energy in comparison to setting the flow rate at the maximum value to handle the worst-case temperature.

Liquid cooling has emerged as a promising solution for addressing the elevated temperatures in 3D stacked architectures. In this work, we first propose a framework for detailed thermal modeling of the microchannels embedded between the tiers of the 3D system. In multicore systems, workload varies at runtime, and the system is generally not fully utilized. Thus, it is not energy-efficient to adjust the coolant flow rate based on the worst-case conditions, as this would cause an excess in pump power. For energy-efficient cooling, we propose a novel controller to adjust the liquid flow rate to meet the desired temperature and to minimize pump energy consumption. Our technique also includes a job scheduler, which balances the temperature across the system to maximize cooling efficiency and to improve reliability. Our method guarantees operating below the target temperature while reducing the cooling energy by up to 30%, and the overall energy by up to 12% in comparison to using the highest coolant flow rate.