We present FlexiFlow, a lifetime-aware design framework for item-level intelligence (ILI) where computation is integrated directly into disposable products like food packaging and medical patches. Our framework leverages natively flexible electronics which offer significantly lower costs than silicon but are limited to kHz speeds and several thousands of gates. Our insight is that unlike traditional computing with more uniform deployment patterns, ILI applications exhibit 1000× variation in operational lifetime, fundamentally changing optimal architectural design decisions when considering trillion-item deployment scales. To enable holistic design and optimization, we model the trade-offs between embodied carbon footprint and operational carbon footprint based on application-specific lifetimes. The framework includes: (1) FlexiBench, a workload suite targeting sustainability applications from spoilage detection to health monitoring; (2) FlexiBits, area-optimized RISC-V cores with 1/4/8-bit datapaths achieving 2.65× to 3.50× better energy efficiency per workload execution; and (3) a carbon-aware model that selects optimal architectures based on deployment characteristics. We show that lifetime-aware microarchitectural design can reduce carbon footprint by 1.62×, while algorithmic decisions can reduce carbon footprint by 14.5×. We validate our approach through the first tape-out using a PDK for flexible electronics with fully open-source tools, achieving 30.9\,kHz operation. FlexiFlow enables exploration of computing at the Extreme Edge where conventional design methodologies must be reevaluated to account for new constraints and considerations. FlexiFlow is available at https://github.com/harvard-edge/FlexiFlow.

Due to the increasing interconnect delay caused by shrinking wiring dimensions, modern synchronous many-core systems are now facing critical issues. Particularly, the power budget to propagate high-frequency clock signals across the chip is limited. It becomes more challenging using conventional metallic interconnects to deliver a clock with low uncertainties across active dies. This article proposes a novel hybrid wireless-wired clock distribution network, which improves the performance of ON-chip clock distribution significantly. By using embedded wireless clock transmitter and receiver designs, because of the high fan-out feature of the wireless clock transmission, the overall clock delay, skew, and power have been reduced. The proposed hybrid clock distribution scheme is verified through a novel test circuit by using Arm Mali-G77 GPU as an example. Experimental results indicate that the proposed clock distribution network exhibits a significant global delay reduction of up to 28.8%. Also, for the best case scenario, a maximum of 46.7% and 17.7% reduction in clock skew and power consumption, are identified, respectively. Thus, our proposed approach offers a promising solution to clock distribution for many-core integrated circuits, especially for high-performance systems.

Battery-operated sensing systems have very low activity rates and power down most blocks during inactive periods to save power. During active periods, these energy-constrained systems typically operate at near or sub-threshold voltage for maintaining energy efficiency. Therefore, these ultra-low energy systems require a read-only, non-volatile code memory that can be accessed at sub-threshold voltage. ROM is the most energy efficient read-only non-volatile memory. A conventional compiler ROM cannot work reliably in near threshold regions of operation due to lack of read margin. As a result, for energy constrained IoT systems, the ROM design needs to support reliable read at low operating voltages, and a speed degradation at low voltages which is at par with logic circuits, to avoid the ROM from limiting the system performance. This paper proposes a sub-threshold ROM that addresses both reliability and performance issues by 1) Using a switched source-line (SSL) to nullify Ioff and improve read margin, 2) Compensating performance degradation caused by SSL using a novel data encoding scheme and by using unused `0' bit-cell transistors to provide local pull-down paths, 3) Tackle variation-based performance degradation by optimizing bit-cell sizing for sub-threshold, and 4) Providing a fine-grained threshold voltage adjustment technique for trading off performance improvement with leakage degradation by using a novel INverse Width Effect (INWE) bit-cell layout. The proposed SSL sub-threshold ROM is fabricated in 65nm technology, with an 8kB capacity, and a Vminof 0.3V. At 0.4V, it has a read speed of 1.1MHz and an access energy of 47fJ/bit.

A live video stream, when encoded and transmitted using a congestion controlled IP flow, experiences a variety of quality of service due to variations in video content activity and bandwidth availability, resulting in frequent oscillations in video quality. By utilizing a reliable metric of perceived quality, we propose a technique for source rate control of real-time live video that maintains a more uniform quality. The method comprises artificial neural networks to generate predictions of the ongoing quality and a fuzzy rate-quality controller that considers properties of human perception of quality in order to provide smooth streaming quality. Experimental results indicate that in the presence of sufficient buffering, the proposed adaptation technique can improve quality stability, while maintaining TCP-friendly transmission.

Networks offering services of high availability and quality need to be carefully monitored. Their increasing size and complexity stresses the ability of currently used static centralized systems. Decentralized approaches are possible and a key issue is the placement of area monitoring stations for optimal operation. Previous research has resulted in computationally expensive algorithms that require a global centralized network view. In this paper we propose a much simpler distributed algorithm and show that it performs as well as existing near-optimal but expensive, centralized algorithms. In addition, we propose that area monitoring stations are mobile agents, cloning and optimally placing themselves by executing the proposed algorithm. As network conditions change, e.g. through faults or persisting congestion, agents can adapt and migrate to new locations. We quantify the benefits of our approach against both the centralized and centrally-computed static distributed approaches.

Distributed Network Management is gaining importance due to the explosive growth of the size of computer networks. New management paradigms are being proposed as an alternative to the centralised one, and new technologies and programming languages are making them feasible. The use of Mobile Agents (MAs) to distribute and delegate management tasks is a particularly promising approach to dealing with the limitations of current centralised management systems which appear to be lacking flexibility and scalability. This paper is focused on the impact that mobile code paradigms can have on distributed network and system monitoring. A dynamic, hierarchical management model based on a delegation paradigm is adopted and an MA-architecture for monitoring operations is proposed. Finally, possible uses of the proposed model and architecture for pursuing seamless and timely monitoring are discussed.

The SNMP and OSI network management standards define two different languages and information models for describing management information. The advocacy of these different approaches is often driven by politics, religion and history as much as by technical considerations. We hope to remain aloof from these partisan arguments and to assess the strengths and weaknesses of the models from the point of view of human managers and of implementors. Comparisons in the literature often focus on performance aspects; load on networks and managed systems, memory requirements, etc. The main focus of our paper is on the information models themselves. Our approach is to explore how the same management information would be modeled within the OSI and SNMP standards. We then assess the results from the point of view of the "naturalness" of the modeling, its extensibility and its likely impact on the efficiency of management interactions. In some networking environments-especially in telecommunications-the OSI and SNMP standards must co-exist. The Network Management Forum (NMF) has defined a series of guidelines concerning coexistence and these include a methodology for translating between information models. We also attempt to assess the effectiveness of the NMF translation rules.

This paper compares three dynamic multipoint routing algorithms for wide-area packet switched networks like asynchronous transfer mode (ATM) networks. The three algorithms compared are the greedy algorithm, the source rooted shortest path (SP) algorithm and the geographic spread dynamic multicast (GSDM) routing algorithm. We present simulation results over random graphs that demonstrate the performance of these algorithms. The algorithms are evaluated via a series of multiple simulations in terms of the number of packet copies per node and their (in)efficiency. A near optimal Steiner tree heuristic algorithm called the KMB algorithm is used as a measure of the (in)efficiency of the algorithms.