Single Events in a COTS Soft-Error Free SRAM at Low Bias Voltage Induced by 15-MeV Neutrons

This paper presents an experimental study of the sensitivity to 15-MeV neutrons of Advanced Low Power SRAMs (A-LPSRAM) at low bias voltage little above the threshold value that allows the retention of data. This family of memories is characterized by a 3D structure to minimize the area penalty and to cope with latchups, as well as by the presence of integrated capacitors to hinder the occurrence of single event upsets. In low voltage static tests, classical single event upsets were a minor source of errors, but other unexpected phenomena such as clusters of bitflips and hard errors turned out to be the origin of hundreds of bitflips. Besides, errors were not observed in dynamic tests at nominal voltage. This behavior is clearly different than that of standard bulk CMOS SRAMs, where thousands of errors have been reported.

Tornado Damage Assessment in the aftermath of the May 20th 2013 Moore Oklahoma Tornado

This report presents observations, findings, and recommendations from an engineering reconnaissance trip following the May 20th, 2013 tornado that struck Moore, Oklahoma. A team of faculty, research scientists, professional engineers, and civil engineering students were tasked with investigating and documenting the performance of critical facility buildings and residences, (IBC Occupancy Category II, III, and IV), in Moore, OK. The Enhanced Fujita (EF) 5 tornado created a 17-mile long damage swath destroying over 12,000 buildings and killing 24 people. The total economic loss from this single event was estimated at $3 billion. The May 20th tornado was the third major tornado to hit Moore in the previous 15 years.

Using ICD-10-AM codes to characterise hospital-acquired complications

This paper describes the limitations of using the International Statistical Classification of Diseases and Related Health Problems, Tenth Revision, Australian Modification (ICD-10-AM) to characterise patient harm in hospitals. Limitations were identified during a project to use diagnoses flagged by Victorian coders as hospital-acquired to devise a classification of 144 categories of hospital acquired diagnoses (the Classification of Hospital Acquired Diagnoses or CHADx). CHADx is a comprehensive data monitoring system designed to allow hospitals to monitor their complication rates month-to-month using a standard method. Difficulties in identifying a single event from linear sequences of codes due to the absence of code linkage were the major obstacles to developing the classification. Obstetric and perinatal episodes also presented challenges in distinguishing condition onset, that is, whether conditions were present on admission or arose after formal admission to hospital. Used in the appropriate way, the CHADx allows hospitals to identify areas for future patient safety and quality initiatives. The value of timing information and code linkage should be recognised in the planning stages of any future electronic systems.

Studies of Earth Dynamics with the Superconducting Gravimeter

The superconducting (or cryogenic) gravimeter (SG) is based on the levitation of a super­conducting sphere in a stable magnetic field created by current in superconducting coils. Depending on frequency, it is capable of detecting gravity variations as small as 10-11ms-2. For a single event, the detection threshold is higher, conservatively about 10-9 ms-2. Due to its high sensitivity and low drift rate, the SG is eminently suitable for the study of geodynamical phenomena through their gravity signatures. I present investigations of Earth dynamics with the superconducting gravimeter GWR T020 at Metsähovi from 1994 to 2005. The history and key technical details of the installation are given. The data processing methods and the development of the local tidal model at Metsähovi are presented. The T020 is a part of the worldwide GGP (Global Geodynamics Project) network, which consist of 20 working station. The data of the T020 and of other participating SGs are available to the scientific community. The SG T020 have used as a long-period seismometer to study microseismicity and the Earth s free oscillation. The annual variation, spectral distribution, amplitude and the sources of microseism at Metsähovi were presented. Free oscillations excited by three large earthquakes were analyzed: the spectra, attenuation and rotational splitting of the modes. The lowest modes of all different oscillation types are studied, i.e. the radial mode 0S0, the "football mode" 0S2, and the toroidal mode 0T2. The very low level (0.01 nms-1) incessant excitation of the Earth s free oscillation was detected with the T020. The recovery of global and regional variations in gravity with the SG requires the modelling of local gravity effects. The most important of them is hydrology. The variation in the groundwater level at Metsähovi as measured in a borehole in the fractured bedrock correlates significantly (0.79) with gravity. The influence of local precipitation, soil moisture and snow cover are detectable in the gravity record. The gravity effect of the variation in atmospheric mass and that of the non-tidal loading by the Baltic Sea were investigated together, as sea level and air pressure are correlated. Using Green s functions it was calculated that a 1 metre uniform layer of water in the Baltic Sea increases the gravity at Metsähovi by 31 nms-2 and the vertical deformation is -11 mm. The regression coefficient for sea level is 27 nms-2m-1, which is 87% of the uniform model. These studies are associated with temporal height variations using the GPS data of Metsähovi permanent station. Results of long time series at Metsähovi demonstrated high quality of data and correctly carried out offsets and drift corrections. The superconducting gravimeter T020 has been proved to be an eminent and versatile tool in studies of the Earth dynamics.

SEU Tolerant Robust Memory Cell Design

The implementation of semiconductor circuits and systems in nano-technology makes it possible to achieve high speed, lower voltage level and smaller area. The unintended and undesirable result of this scaling is that it makes integrated circuits susceptible to soft errors normally caused by alpha particle or neutron hits. These events of radiation strike resulting into bit upsets referred to as single event upsets(SEU), become increasingly of concern for the reliable circuit operation in the field. Storage elements are worst hit by this phenomenon. As we further scale down, there is greater interest in reliability of the circuits and systems, apart from the performance, power and area aspects. In this paper we propose an improved 12T SEU tolerant SRAM cell design. The proposed SRAM cell is economical in terms of area overhead. It is easy to fabricate as compared to earlier designs. Simulation results show that the proposed cell is highly robust, as it does not flip even for a transient pulse with 62 times the Q(crit) of a standard 6T SRAM cell.

Lessons from History for Transitions to a Low Carbon Economy

4 p.

The Slow Search for Solutions: Lessons from Historical Energy Transitions by Sector and Service

28 p.

Future of earthquake early warning : quantifying uncertainty and making fast automated decisions for applications

Earthquake early warning (EEW) systems have been rapidly developing over the past decade. Japan Meteorological Agency (JMA) has an EEW system that was operating during the 2011 M9 Tohoku earthquake in Japan, and this increased the awareness of EEW systems around the world. While longer-time earthquake prediction still faces many challenges to be practical, the availability of shorter-time EEW opens up a new door for earthquake loss mitigation. After an earthquake fault begins rupturing, an EEW system utilizes the first few seconds of recorded seismic waveform data to quickly predict the hypocenter location, magnitude, origin time and the expected shaking intensity level around the region. This early warning information is broadcast to different sites before the strong shaking arrives. The warning lead time of such a system is short, typically a few seconds to a minute or so, and the information is uncertain. These factors limit human intervention to activate mitigation actions and this must be addressed for engineering applications of EEW. This study applies a Bayesian probabilistic approach along with machine learning techniques and decision theories from economics to improve different aspects of EEW operation, including extending it to engineering applications.

Existing EEW systems are often based on a deterministic approach. Often, they assume that only a single event occurs within a short period of time, which led to many false alarms after the Tohoku earthquake in Japan. This study develops a probability-based EEW algorithm based on an existing deterministic model to extend the EEW system to the case of concurrent events, which are often observed during the aftershock sequence after a large earthquake.

To overcome the challenge of uncertain information and short lead time of EEW, this study also develops an earthquake probability-based automated decision-making (ePAD) framework to make robust decision for EEW mitigation applications. A cost-benefit model that can capture the uncertainties in EEW information and the decision process is used. This approach is called the Performance-Based Earthquake Early Warning, which is based on the PEER Performance-Based Earthquake Engineering method. Use of surrogate models is suggested to improve computational efficiency. Also, new models are proposed to add the influence of lead time into the cost-benefit analysis. For example, a value of information model is used to quantify the potential value of delaying the activation of a mitigation action for a possible reduction of the uncertainty of EEW information in the next update. Two practical examples, evacuation alert and elevator control, are studied to illustrate the ePAD framework. Potential advanced EEW applications, such as the case of multiple-action decisions and the synergy of EEW and structural health monitoring systems, are also discussed.

Procedimentos utilizados pela Auditoria Interna para detecção de fraudes: estudo de caso em uma empresa privada operadora de planos de saúde

A presente pesquisa objetiva verificar se os procedimentos utilizados pela Auditoria Interna na detecção de fraudes em uma empresa privada operadora de planos de saúde permitiram a coleta de evidências confiáveis e suficientes para suportar as conclusões dos auditores sobre os fatos reportados nos relatórios de auditoria interna. Para realização do estudo, adotou-se como estratégia investigativa, o estudo de caso único. As técnicas utilizadas ao longo de toda a pesquisa foram as análises documentais e de conteúdo, baseadas nos objetivos propostos no estudo e na fundamentação teórica. A pesquisa concentrou-se nas análises dos relatórios de auditoria interna que reportaram ocorrências de fraudes na empresa estudada, emitidos nos anos de 2010, 2011 e 2012; contudo optou-se, também, por descrever as rotinas e práticas operacionais relacionadas à atuação do departamento de auditoria que contribuíram para uma melhor compreensão dos dados e do resultado do estudo. Os principais achados demonstram que os procedimentos utilizados pela Auditoria Interna na detecção de fraudes permitiram a coleta de evidências de auditoria confiáveis e suficientes para suportar as conclusões dos auditores. O resultado da pesquisa indica, também, que não existe um padrão de utilização dos procedimentos de auditoria. De acordo com o tipo de fraude e objetivo, o auditor interno deve definir quais os procedimentos de auditoria devem ser utilizados na obtenção de evidências de auditoria confiáveis e suficientes para suportar as suas conclusões.

Analysis of SEB and SEGR in super-junction MOSFETs

The electric field distribution in the super junction power MOSFET is analyzed using analytical modeling and numerical simulations in this paper. The single-event burn-out (SEB) and single-event gate rupture (SEGR) phenomena in this device are studied in detail. It is demonstrated that the super junction device is much less sensitive to SEB and SEGR compared to the standard power MOSFET. The physical mechanism is explained.

单粒子效应地面模拟实验装置和IDT71256的单粒子效应研究

作为空间环境效应之一的单粒子效应对航天器在轨道中的安全运行有着严重的威胁。为了清楚地认识这一效应的机制、机理，可以采用重离子加速器地面模拟的方法来研究这一效应。为此建立和完善了国内第一套基于重离子加速器的单粒子效应地面模拟实验装置，并在此装置上进行了Xe离子辐照IDT71256的单粒了效应实验。建立的基于兰州重离子加速器的单粒子效应地面模拟实验装置包括真空靶室系统和束流监测系统。实验用兰州重离子加速器提供的~(40)Ar完成了对整个装置的性能测试。结果表明：该装置能很好的满足单粒子效应研究的需求，真空靶室系统允许在不破坏真空的条件下更换器件，改变倾角，改变离子入射能量等。注量探测器实现了对弱束流非拦截式测量；能量探测器对Ar离子测量的偏差小于2%；束流均匀度探测器的位置分辨好于0.34mm。在这一实验装置上，用兰州重离子加速器提供的~(136)Xe对两片IDT71256的单粒子效应情况进行了模拟研究。结果发现：在两片器件中均观察到单粒子翻转和单粒子闭锁，而且两片器件均表现出明显的翻转不对称性，其中1→0的翻转约占总翻转数的90%。探讨了离子入射角、有效LET、和离子射程对翻转和闭锁截面的影响，发现除离子的有效LET以外，离子在器件中的射程也将在很大程度上影响器件的翻转和闭锁截面。

利用HIRFL评估半导体器件单粒子效应敏感度的研究

用55MeV/u的~(40)Ar，离子对国内第一台专用的单粒子效应加速器模拟实验装置的注时探测器、能量探测器以及均匀度探测器进行了刻度。利用高能~(136)Xe离子获得了静态存储器IDT71256的单粒子翻转饱和截面和单粒子闭锁截面，在国内首次得到了该器件完整的G一LET曲线。并用改进的FONT方法预示了该器件以及其它常用宇航器件的在轨翻转率；用FOM公式、Barak经验公式和Lar叮模型推算这些器件的质子饱爪佩截而，少一仁对二种方法推算的结果进行了比较；探讨了利用HIRFL提供的高能~(12)C离子来模拟质子引起的单粒子效应的可能性；利用翻转截面与离子入射角度的关系估算了IDT71256敏感区的厚度以及聚酞亚胺膜的厚度，获得了截面与离子沉积能量的关系，临界沉积能量与临界LET值吻合，聚酞亚胺膜的厚度与对同类器件测量的结果一致；研究了离子入射角度对多位翻转的影响，在高LET值轰击下以及高能离子掠射的情况下，IDT71256多位翻转的比例可以高达70％，对于MBU敏感区中沉积的总能量及其分布范围是两个重要的参数；IDT71256单粒子翻转截面的角度效应主要是多位翻转的贡献；对实验中各种误差来源进行了分析。部分研究结果己经应用于星载七卜算机系统的抗辐射加固设计，建立的实验方法和理论模型为利用HIRFL开展宇航器件单粒子效应敏感度的评估奠定了坚实的基础。

Effects of task instruction on autobiographical memory specificity in young and older adults

Older adults tend to retrieve autobiographical information that is overly general (i.e., not restricted to a single event, termed the overgenerality effect) relative to young adults' specific memories. A vast majority of studies that have reported overgenerality effects explicitly instruct participants to retrieve specific memories, thereby requiring participants to maintain task goals, inhibit inappropriate responses, and control their memory search. Since these processes are impaired in healthy ageing, it is important to determine whether such task instructions influence the magnitude of the overgenerality effect in older adults. In the current study participants retrieved autobiographical memories during presentation of musical clips. Task instructions were manipulated to separate age-related differences in the specificity of underlying memory representations from age-related differences in following task instructions. Whereas young adults modulated memory specificity based on task demands, older adults did not. These findings suggest that reported rates of overgenerality in older adults' memories might include age-related differences in memory representation, as well as differences in task compliance. Such findings provide a better understanding of the underlying cognitive mechanisms involved in age-related changes in autobiographical memory and may also be valuable for future research examining effects of overgeneral memory on general well-being. © 2013 Taylor & Francis.

Effects of task instruction on autobiographical memory specificity in young and older adults.

Older adults tend to retrieve autobiographical information that is overly general (i.e., not restricted to a single event, termed the overgenerality effect) relative to young adults' specific memories. A vast majority of studies that have reported overgenerality effects explicitly instruct participants to retrieve specific memories, thereby requiring participants to maintain task goals, inhibit inappropriate responses, and control their memory search. Since these processes are impaired in healthy ageing, it is important to determine whether such task instructions influence the magnitude of the overgenerality effect in older adults. In the current study participants retrieved autobiographical memories during presentation of musical clips. Task instructions were manipulated to separate age-related differences in the specificity of underlying memory representations from age-related differences in following task instructions. Whereas young adults modulated memory specificity based on task demands, older adults did not. These findings suggest that reported rates of overgenerality in older adults' memories might include age-related differences in memory representation, as well as differences in task compliance. Such findings provide a better understanding of the underlying cognitive mechanisms involved in age-related changes in autobiographical memory and may also be valuable for future research examining effects of overgeneral memory on general well-being.

Proteomic Analysis of Recurrent Joint Inflammation in Juvenile Idiopathic Arthritis

The synovial fluid proteome in juvenile idiopathic arthritis was investigated to isolate joint-specific biomarkers that are expressed in patients displaying recurrent joint inflammation. To identify the synovial specific proteome, matched synovial fluid and plasma samples were subjected to protein separation by 2-dimension electrophoresis (2DE). Forty-three protein spots, overexpressed in the joint, were identified. Synovial fluids from children with single-event knee joint inflammation were then compared with a group with recurrent knee disease. Nine synovial specific proteins were significantly differentially expressed in the recurrent group. Proteolytic fragments of collagen X, fibrin beta-chain, and T-cell receptor alpha-region have been identified among this protein cluster. Putative biomarkers, overexpressed in the joint and differentially expressed in children with recurrent joint inflammation, have been identified. These proteins may play a significant role determining the pathological state within the chronically inflamed joint and influence disease progression in JIA. This is the first study of the synovial proteome in children.