Enabling Fine-Grain Restricted Coset Coding Through Word-Level Compression for PCM

Phase change memory (PCM) has recently emerged as a promising technology to meet the fast growing demand for large capacity memory in computer systems, replacing DRAM that is impeded by physical limitations. Multi-level cell (MLC) PCM offers high density with low per-byte fabrication cost. However, despite many advantages, such as scalability and low leakage, the energy for programming intermediate states is considerably larger than programing single-level cell PCM. In this paper, we study encoding techniques to reduce write energy for MLC PCM when the encoding granularity is lowered below the typical cache line size. We observe that encoding data blocks at small granularity to reduce write energy actually increases the write energy because of the auxiliary encoding bits. We mitigate this adverse effect by 1) designing suitable codeword mappings that use fewer auxiliary bits and 2) proposing a new Word-Level Compression (WLC) which compresses more than 91% of the memory lines and provides enough room to store the auxiliary data using a novel restricted coset encoding applied at small data block granularities. Experimental results show that the proposed encoding at 16-bit data granularity reduces the write energy by 39%, on average, versus the leading encoding approach for write energy reduction. Furthermore, it improves endurance by 20% and is more reliable than the leading approach. Hardware synthesis evaluation shows that the proposed encoding can be implemented on-chip with only a nominal area overhead.Comment: 12 page

Energy and Climate Change Issues Around CSUDH

Climate change is posing significant challenges to California’s energy sector. Extreme weather events (heat and cold) may pressure existing infrastructure. Many studies have indicated that extreme climate events would impact the energy system by affecting peak electricity demand. However, very few studies have been conducted to understand how disadvantaged communities (DACs) will be impacted. Because of unequal access to energy infrastructure (electricity generation and battery storage), DACs are more vulnerable to power outages due to the rising number of significant weather events caused by climate change. To address the issue of how DACs are disproportionately affected by climate change-related energy issues, we used DACs, infrastructure, and climate data. We identified the most vulnerable communities associated with climate change-related energy issues in areas around California State University Dominguez Hills (CSUDH). This study’s findings will support building the resilience of energy infrastructure to climate change and minimize the energy burden on DACs

DNA Pre-alignment Filter using Processing Near Racetrack Memory

Recent DNA pre-alignment filter designs employ DRAM for storing the reference genome and its associated meta-data. However, DRAM incurs increasingly high energy consumption background and refresh energy as devices scale. To overcome this problem, this paper explores a design with racetrack memory (RTM)--an emerging non-volatile memory that promises higher storage density, faster access latency, and lower energy consumption. Multi-bit storage cells in RTM are inherently sequential and thus require data placement strategies to mitigate the performance and energy impacts of shifting during data accesses. We propose a near-memory pre-alignment filter with a novel data mapping and several shift reduction strategies designed explicitly for RTM. On a set of four input genomes from the 1000 Genome Project, our approach improves performance and energy efficiency by 68% and 52%, respectively, compared to the state of the art proposed DRAM-based architecture

PIRM: Processing In Racetrack Memories

The growth in data needs of modern applications has created significant challenges for modern systems leading a "memory wall." Spintronic Domain Wall Memory (DWM), related to Spin-Transfer Torque Memory (STT-MRAM), provides near-SRAM read/write performance, energy savings and nonvolatility, potential for extremely high storage density, and does not have significant endurance limitations. However, DWM's benefits cannot address data access latency and throughput limitations of memory bus bandwidth. We propose PIRM, a DWM-based in-memory computing solution that leverages the properties of DWM nanowires and allows them to serve as polymorphic gates. While normally DWM is accessed by applying spin polarized currents orthogonal to the nanowire at access points to read individual bits, transverse access along the DWM nanowire allows the differentiation of the aggregate resistance of multiple bits in the nanowire, akin to a multilevel cell. PIRM leverages this transverse reading to directly provide bulk-bitwise logic of multiple adjacent operands in the nanowire, simultaneously. Based on this in-memory logic, PIRM provides a technique to conduct multi-operand addition and two operand multiplication using transverse access. PIRM provides a 1.6x speedup compared to the leading DRAM PIM technique for query applications that leverage bulk bitwise operations. Compared to the leading PIM technique for DWM, PIRM improves performance by 6.9x, 2.3x and energy by 5.5x, 3.4x for 8-bit addition and multiplication, respectively. For arithmetic heavy benchmarks, PIRM reduces access latency by 2.1x, while decreasing energy consumption by 25.2x for a reasonable 10% area overhead versus non-PIM DWM.Comment: This paper is accepted to the IEEE/ACM Symposium on Microarchitecture, October 2022 under the title "CORUSCANT: Fast Efficient Processing-in-Racetrack Memories

Methods and apparatus for switching a transponder to an active state, and asset management systems employing same

A transponder that may be used as an RFID tag includes a passive circuit to eliminate the need for an "always on" active RF receiving element to anticipate a wake-up signal for the balance of the transponder electronics. This solution allows the entire active transponder to have all circuit elements in a sleep (standby) state, thus drastically extending battery life or other charge storage device life. Also, a wake-up solution that reduces total energy consumption of an active transponder system by allowing all non-addressed transponders to remain in a sleep (standby) state, thereby reducing total system or collection energy. Also, the transponder and wake-up solution are employed in an asset tracking system

Receptor for Fc on the surfaces of schistosomes

Schistosoma mansoni masks its surface with adsorbed host proteins including erythrocyte antigens, immunoglobulins, major histocompatibility complex class I, and beta (2)-microglobulin (beta (2)m), presumably as a means of avoiding host immune responses, How this is accomplished has not been explained. To identify surface receptors for host proteins, we biotinylated the tegument of live S, mansoni adults and mechanically transformed schistosomula and then removed the parasite surface with detergent, Incubation of biotinylated schistosome surface extracts witt l human immunoglobulin G (IgG) Fc-Sepharose resulted in purification of a 97-kDa protein that was subsequently identified as paramyosin (Pmy), using antiserum specific for recombinant Pmy, Fc also bound recombinant S. mansoni Pmy and native S. japonicum Pmy, Antiserum to Pmy decreased the binding of Pmy to Fc-Sepharose, and no proteins bound after removal of Pmy from extracts. Fluoresceinated human Fe bound to the surface, vestigial penetration glands, and nascent oral cavity of mechanically transformed schistosomula, and rabbit anti-Pmy Fab fragments ablated the binding of Fc to the schistosome surface, Pmy coprecipitated with host IgG from parasite surface extracts, indicating that complexes formed on the parasite surface as well as in vitro. Binding of Pmy to Fe was not inhibited by soluble protein A, suggesting that Pmy does not bind to the region between the CH2 and CH3 domains used by many other Fc-binding proteins. beta (2)m did not bind to the schistosome Fc receptor (Pmy), a finding that contradicts reports from earlier workers but did bind to a heteromultimer of labeled schistosomula surface proteins, This is the first report of the molecular identity of a schistosome Fc receptor; moreover it demonstrates an additional aspect of the unusual and multifunctional properties of Pmy from schistosomes and other parasitic flatworms

A unique bacteriohopanetetrol stereoisomer of marine anammox

Anaerobic ammonium oxidation (anammox) is a major process of bioavailable nitrogen removal from marine systems. Previously, a bacteriohopanetetrol (BHT) isomer, with unknown stereochemistry, eluting later than BHT using high performance liquid chromatography (HPLC), was detected in ‘Ca. Scalindua profunda’ and proposed as a biomarker for anammox in marine paleo-environments. However, the utility of this BHT isomer as an anammox biomarker is hindered by the fact that four other, non-anammox bacteria are also known to produce a late-eluting BHT stereoisomer. The stereochemistry in Acetobacter pasteurianus, Komagataeibacter xylinus and Frankia sp. was known to be 17β, 21β(H), 22R, 32R, 33R, 34R (BHT-34R). The stereochemistry of the late-eluting BHT in Methylocella palustris was unknown. To determine if marine anammox bacteria produce a unique BHT isomer, we studied the BHT distributions and stereochemistry of known BHT isomer producers and of previously unscreened marine (‘Ca. Scalindua brodeae’) and freshwater (‘Ca. Brocadia sp.’) anammox bacteria using HPLC and gas chromatographic (GC) analysis of acetylated BHTs and ultra high performance liquid chromatography (UHPLC)-high resolution mass spectrometry (HRMS) analysis of non-acetylated BHTs. The 34R stereochemistry was confirmed for the BHT isomers in Ca. Brocadia sp. and Methylocella palustris. However, ‘Ca. Scalindua sp.’ synthesise a stereochemically distinct BHT isomer, with still unconfirmed stereochemistry (BHT-x). Only GC analysis of acetylated BHT and UHPLC analysis of non-acetylated BHT distinguished between late-eluting BHT isomers. Acetylated BHT-x and BHT-34R co-elute by HPLC. As BHT-x is currently only known to be produced by ‘Ca. Scalindua spp.’, it may be a biomarker for marine anammox

Design space exploration for low-power reconfigurable fabrics

Field Programmable Gate Array (FPGA)-like programmability and Computer Aided Design (CAD), with Application Specific Integrated Circuit (ASIC)-like power characteristics for Digital Signal Processing (DSP) style applications. Using this model, architectural design space decisions are explored in order to define an energy-efficient fabric. The impact on energy and performance due to the variation of different parameters such as datawidth and interconnection flexibility has been studied. The multiplexer cardinality usage has also been studied by mapping some of the signal processing applications onto the fabric. The results point to the use of power optimized 32-bit width computational elements interconnected by low cardinality multiplexers like 4:1 multiplexers. I