Secure, Reliable, and Energy-efficient Phase Change Main Memory

Recent trends in supercomputing, shared cloud computing, and “big data” applications are placing ever-greater demands on computing systems and their memories. Such applications can readily saturate memory bandwidth, and often operate on a working set which exceeds the capacity of modern DRAM packages. Unfortunately, this demand is not matched by DRAM technology development. As Moore’s Law slows and Dennard Scaling stops, further density improvements in DRAM and the underlying semiconductor devices are difficult [1]. In anticipation of this limitation, researchers have pursued emerging memory technologies that promise higher density than conventional DRAM devices. One such technology in phase-change memory (PCM) is especially desirable due to its increased density relative to DRAM. However, this nascent memory has outstanding challenges to overcome before it is viable as a DRAM replacement. PCM devices have limited write endurance, and can consume more energy than their DRAM counterparts, necessitating careful control of how and how often they are written. A second challenge is the non-volatile nature of PCM devices; many applications rely on the volatility of DRAM to protect security critical applications and operating system address space between accesses and power cycles. An obvious solution is to encrypt the memory, but the effective randomization of data is at odds with techniques which reduce writes to the underlying memory. This body of work presents three contributions for addressing all challenges simultaneously under the assumption that encryption is required. Using an encryption and encoding technique called CASTLE & TOWERs, PCM can be employed as main memory with up to 30× improvement in device lifetime while opportunistically reducing dynamic energy. A second technique called MACE marries encoding and traditional error-correction schemes providing up to 2.6× improvement in device lifetime alongside a whole-lifetime energy evaluation framework to guide system design. Finally, an architecture called WINDU is presented which supports the application of encoding for an emerging encryption standard with an eye on energy efficiency. Together, these techniques advance the state-of-the-art, and offer a significant step toward the adoption of PCM as a main memory

Funding and Strategic Alignment Guidance for Infusing Small Business Innovation Research Technology Into Aeronautics Research Mission Directorate Projects at NASA Glenn Research Center for 2015

This document is intended to enable the more effective transition of NASA Glenn Research Center (GRC) SBIR technologies funded by the Small Business Innovation Research (SBIR) program as well as its companion, the Small Business Technology Transfer (STTR) program into NASA Aeronautics Research Mission Directorate (ARMD) projects. Primarily, it is intended to help NASA program and project managers find useful technologies that have undergone extensive research and development (RRD), through Phase II of the SBIR program; however, it can also assist non-NASA agencies and commercial companies in this process. aviation safety, unmanned aircraft, ground and flight test technique, low emissions, quiet performance, rotorcraf

Achieving Reliable and Sustainable Next-Generation Memories

Conventional memory technology scaling has introduced reliability challenges due to dysfunctional, improperly formed cells and crosstalk from increased cell proximity. Furthermore, as the manufacturing effort becomes increasingly complex due to these deeply scaled technologies, holistic sustainability is negatively impacted. The development of new memory technologies can help overcome the capacitor scaling limitations of DRAM. However, these technologies have their own reliability concerns, such as limited write endurance in the case of Phase Change Memories (PCM). Moreover, emerging system requirements, such as in-memory encryption to protect sensitive or private data and operation in harsh environments create additional challenges that must be addressed in the context of reliability and sustainability. This dissertation provides new multifactor and ultimately unified solutions to address many of these concerns in the same system. In particular, my contributions toward mitigating these issues are as follows. I present GreenChip and GreenAsic, which together provide the first tools to holistically evaluate new computer architecture, chip, and memory design concepts for sustainability. These tools provide detailed estimates of manufacturing and operational-phase metrics for different computing workloads and deployment scenarios. Using GreenChip, I examined existing DRAM reliability techniques in the context of their holistic sustainability impact, including my own technique to mitigate bitline crosstalk. For PCM, I provided a new reliability technique with no additional storage overhead that substantially increases the lifetime of an encrypted memory system. To provide bit-level error correction, I developed compact linked-list and Bloom-filter-based bit-level fault map structures, that provide unprecedented levels of error tabulation, combined with my own novel error correction and lifetime extension approaches based on these maps for less area than traditional ECC. In particular, FaME, can correct N faults using N bits when utilizing a bit-level fault map. For operation in harsh environments, I created a triple modular redundancy (TMR) pointer-based fault map, HOTH, which specifically protects cells shown to be weak to radiation. Finally, to combine the analyses of holistic sustainability and memory lifetime, I created the LARS technique, which adjusts the GreenChip indifference analysis to account for the additional sustainability benefit provided by increased reliability and lifetime

Towards end-to-end security in internet of things based healthcare

Healthcare IoT systems are distinguished in that they are designed to serve human beings, which primarily raises the requirements of security, privacy, and reliability. Such systems have to provide real-time notifications and responses concerning the status of patients. Physicians, patients, and other caregivers demand a reliable system in which the results are accurate and timely, and the service is reliable and secure. To guarantee these requirements, the smart components in the system require a secure and efficient end-to-end communication method between the end-points (e.g., patients, caregivers, and medical sensors) of a healthcare IoT system. The main challenge faced by the existing security solutions is a lack of secure end-to-end communication. This thesis addresses this challenge by presenting a novel end-to-end security solution enabling end-points to securely and efficiently communicate with each other. The proposed solution meets the security requirements of a wide range of healthcare IoT systems while minimizing the overall hardware overhead of end-to-end communication. End-to-end communication is enabled by the holistic integration of the following contributions. The first contribution is the implementation of two architectures for remote monitoring of bio-signals. The first architecture is based on a low power IEEE 802.15.4 protocol known as ZigBee. It consists of a set of sensor nodes to read data from various medical sensors, process the data, and send them wirelessly over ZigBee to a server node. The second architecture implements on an IP-based wireless sensor network, using IEEE 802.11 Wireless Local Area Network (WLAN). The system consists of a IEEE 802.11 based sensor module to access bio-signals from patients and send them over to a remote server. In both architectures, the server node collects the health data from several client nodes and updates a remote database. The remote webserver accesses the database and updates the webpage in real-time, which can be accessed remotely. The second contribution is a novel secure mutual authentication scheme for Radio Frequency Identification (RFID) implant systems. The proposed scheme relies on the elliptic curve cryptography and the D-Quark lightweight hash design. The scheme consists of three main phases: (1) reader authentication and verification, (2) tag identification, and (3) tag verification. We show that among the existing public-key crypto-systems, elliptic curve is the optimal choice due to its small key size as well as its efficiency in computations. The D-Quark lightweight hash design has been tailored for resource-constrained devices. The third contribution is proposing a low-latency and secure cryptographic keys generation approach based on Electrocardiogram (ECG) features. This is performed by taking advantage of the uniqueness and randomness properties of ECG's main features comprising of PR, RR, PP, QT, and ST intervals. This approach achieves low latency due to its reliance on reference-free ECG's main features that can be acquired in a short time. The approach is called Several ECG Features (SEF)-based cryptographic key generation. The fourth contribution is devising a novel secure and efficient end-to-end security scheme for mobility enabled healthcare IoT. The proposed scheme consists of: (1) a secure and efficient end-user authentication and authorization architecture based on the certificate based Datagram Transport Layer Security (DTLS) handshake protocol, (2) a secure end-to-end communication method based on DTLS session resumption, and (3) support for robust mobility based on interconnected smart gateways in the fog layer. Finally, the fifth and the last contribution is the analysis of the performance of the state-of-the-art end-to-end security solutions in healthcare IoT systems including our end-to-end security solution. In this regard, we first identify and present the essential requirements of robust security solutions for healthcare IoT systems. We then analyze the performance of the state-of-the-art end-to-end security solutions (including our scheme) by developing a prototype healthcare IoT system

ENSURING SPECIFICATION COMPLIANCE, ROBUSTNESS, AND SECURITY OF WIRELESS NETWORK PROTOCOLS

Several newly emerged wireless technologies (e.g., Internet-of-Things, Bluetooth, NFC)—extensively backed by the tech industry—are being widely adopted and have resulted in a proliferation of diverse smart appliances and gadgets (e.g., smart thermostat, wearables, smartphones), which has ensuingly shaped our modern digital life. These technologies include several communication protocols that usually have stringent requirements stated in their specifications. Failing to comply with such requirements can result in incorrect behaviors, interoperability issues, or even security vulnerabilities. Moreover, lack of robustness of the protocol implementation to malicious attacks—exploiting subtle vulnerabilities in the implementation—mounted by the compromised nodes in an adversarial environment can limit the practical utility of the implementation by impairing the performance of the protocol and can even have detrimental effects on the availability of the network. Even having a compliant and robust implementation alone may not suffice in many cases because these technologies often expose new attack surfaces as well as new propagation vectors, which can be exploited by unprecedented malware and can quickly lead to an epidemic

Understanding the Impact of Childhood Maltreatment on Episstemic Trust, Learning and Psychopathology Throughout the Lifespan

Part 1presents a systematic literature review of 20 quantitative papers comparing maltreated and non-maltreated children’s performance on memory tasks involving varying degrees of interpersonal information. Findings suggest that children’s basic memory processes may be impaired when the to be remembered information contains more interpersonal content, however heterogeneity in terminology and methodology between studies impede the ability to draw firm conclusions. Part 2, which was part of a joint thesis project with MacGregor (2021), uses a novel retrospective measure of childhood maltreatment to explore the relationship between temporal characteristics of maltreatment subtypes and adult psychopathology symptomatology. The role of impaired social learning, as measured by a social learning task completed under one of four ostensive cue conditions, is also explored. Chronicity of maltreatment, and peer emotional bullying were identified as particular risk factors for adult psychopathology symptoms. Social learning was not found to mediate such associations. Part 3 provides a critical appraisal of the research process, considering the impact of completing this piece of work in the Covid-19 context, before moving on to consider the influence of previous personal clinical and research experience on the process. Implications of the research findings for future research, clinical practice, and my own career are considered

Rakennuksen käyttöjärjestelmän luonti: kokonaisvaltainen lähestymistapa

Purpose of this thesis is to examine requirements for a building operating system from a holistic perspective. To understand the context of the subject, an extensive literature review was carried out which explores the evolution of operating systems alongside the history of computing, unravelling the concept of an operating system. In addition, various building information systems, including building automation systems and internet of things systems are reviewed in order to understand modern and future trends of building technology. Furthermore, literature review investigates telecommunications and digital identity authentication through their evolution and standardisation towards interoperability, to provide knowledge on how to achieve interoperability in building systems. An interview study was conducted as the empirical part of the study in order to complement the theoretical framework of the thesis. A dozen building digitalisation experts were interviewed, inquiring their insights on the current and future situation of building systems. More closely, open systems, open data, platform ownership, disruption, killer applications, user-centredness, and Finland’s opportunities were discussed in respect of the building operating system. Building operating system requires connection between various technology inside a building, and collaboration between various parties who use and manage the building. The system should exploit open standards and enable open data. User-centred development should be encouraged for the benefits of end users. The system needs to expand globally to achieve critical mass and unleash its full potential as a platform. Each building with similar properties should have the same features, being able to use same services and applications in any building with an operating system, thus enabling portability. The system requires convenient software development kits, application programming interfaces and abstractions for the needs of software and service developers. A vibrant developer community is required to expand the platform and enable a wide range of services and applications.Tämän diplomityön tarkoituksena on tutkia rakennuksen käyttöjärjestelmän holistisia vaatimuksia. Laaja kirjallisuuskatsaus tehtiin aiheen ymmärtämiseksi, joka tutkii käyttöjärjestelmien evoluutiota rinnakkain tietojenkäsittelyn historian kanssa, tarkoituksena hahmottaa käyttöjärjestelmän käsitettä. Lisäksi, eri rakennusten tietojärjestelmiä, mukaan lukien rakennusautomaatiojärjestelmiä ja esineiden internet -järjestelmiä käytiin läpi ymmärtääkseen nykyisiä ja tulevia trendejä rakennusteknologiassa. Edelleen kirjallisuuskatsaus tutkii televiestintää ja sähköistä tunnistautumista niiden kehityksen ja standardisoinnin kautta kohti yhteentoimivuutta, tarjoten tietoa siitä, miten yhteentoimivuutta voitaisiin kehittää rakennusjärjestelmissä. Haastattelututkimus tehtiin diplomityön empiirisenä osuutena, jonka tarkoituksena oli laajentaa työn teoreettista viitekehystä. Tusina rakennusten digitalisaation asiantuntijaa haastateltiin, joilta kysyttiin rakennusjärjestelmien nykytilasta ja tulevaisuudesta. Lähemmin, keskustelut käsittelivät avoimia järjestelmiä, avointa dataa, alustan omistajuutta, disruptiota, menestyssovelluksia, käyttäjäkeskeisyyttä sekä Suomen kansainvälistä potentiaalia rakennuksen käyttöjärjestelmän näkökulmasta. Rakennuksen käyttöjärjestelmä vaatii rakennuksen sisällä olevien eri teknologioiden yhteenliittämisen, sekä yhteistyötä rakennusta käyttävien ja hallinnoivien osapuolten välillä. Järjestelmän pitäisi hyödyntää avoimia standardeja ja mahdollistaa avoimen datan käytön. Käyttäjäkeskeistä suunnittelua pitäisi kannustaa loppukäyttäjien etuja suosien. Järjestelmän täytyy levitä globaalisti saavuttaakseen kriittisen massan ja ottaakseen käyttöön sen koko potentiaalin. Jokaisella samankaltaisella rakennuksella täytyisi olla käytössään yhtäläiset ominaisuudet, mahdollistaen samojen palveluiden ja sovellusten käytön missä tahansa käyttöjärjestelmää käyttävässä rakennuksessa, täten mahdollistaen siirrettävyyden. Järjestelmä vaatii sopivat ohjelmointirajapinnat, abstraktiot ja ohjelmistokehykset sovellus- ja palvelukehittäjien tarpeita varten. Laaja kehitysyhteisö vaaditaan alustan levittämiseksi ja sovellustarjonnan laajentamiseksi

State of the art survey of technologies applicable to NASA's aeronautics, avionics and controls program

The state of the art survey (SOAS) covers six technology areas including flightpath management, aircraft control system, crew station technology, interface & integration technology, military technology, and fundamental technology. The SOAS included contributions from over 70 individuals in industry, government, and the universities

Change blindness: eradication of gestalt strategies

Arrays of eight, texture-defined rectangles were used as stimuli in a one-shot change blindness (CB) task where there was a 50% chance that one rectangle would change orientation between two successive presentations separated by an interval. CB was eliminated by cueing the target rectangle in the first stimulus, reduced by cueing in the interval and unaffected by cueing in the second presentation. This supports the idea that a representation was formed that persisted through the interval before being 'overwritten' by the second presentation (Landman et al, 2003 Vision Research 43149–164]. Another possibility is that participants used some kind of grouping or Gestalt strategy. To test this we changed the spatial position of the rectangles in the second presentation by shifting them along imaginary spokes (by ±1 degree) emanating from the central fixation point. There was no significant difference seen in performance between this and the standard task [F(1,4)=2.565, p=0.185]. This may suggest two things: (i) Gestalt grouping is not used as a strategy in these tasks, and (ii) it gives further weight to the argument that objects may be stored and retrieved from a pre-attentional store during this task

Maternal social capital and child growth: Do grandmothers help?

Evolutionary life history theory assumes that the resources available to an organism in any environment are finite and that each organism has been selected to allocate those resources in ways that maximize reproductive fitness. In humans, high levels of parental investment are required to raise offspring, because of their large, costly brains. The costs borne by each individual mother may be mitigated by obtaining social support from other family members. Maternal grandmothers could be a particularly reliable source of support because of the high degree of genetic relatedness and since they represent a valuable source of knowledge and resources, and can release mothers from the 'energetic demands’ of childcare. This thesis tested the over-arching hypothesis that women with grandmothers’ support would have more favourable physiological and psychological characteristics that, in turn, would be associated with healthier growth patterns and lower levels of irritability in their children. To test this hypothesis, a cohort of 90 mother-infant dyads (52 with grandmothers’ support, 38 without) was recruited in Merida, Mexico. Children were first-borns and aged 1.7-2.3 years. Anthropometric and body composition data and behavioural and physiological markers of stress (salivary cortisol) in both mother and child were assessed. Additional data on maternal resilience and self-efficacy and infant temperament were obtained. In the whole population, mothers showed high levels of self-efficacy and resilience and perceived their children as having favourable temperament, suggesting that mothers with greater psychosocial capital have a positive impact on their child’s development. However, there were no differences between the groups in stress markers or nutritional status among mothers or infants. Notably, mothers without grandmaternal support benefitted from higher levels of support from other female family members. In conclusion, mothers can find different sources of social support for rearing their children, and those lacking a grandmother are not at a systematic disadvantage