Nondestructive SEM for surface and subsurface wafer imaging

The scanning electron microscope (SEM) is considered as a tool for both failure analysis as well as device characterization. A survey is made of various operational SEM modes and their applicability to image processing methods on semiconductor devices

Designing a Photonic Physically Unclonable Function Having Resilience to Machine Learning Attacks

Physically unclonable functions (PUFs) are designed to act as device 'fingerprints.' Given an input challenge, the PUF circuit should produce an unpredictable response for use in situations such as root-of-trust applications and other hardware-level cybersecurity applications. PUFs are typically subcircuits present within integrated circuits (ICs), and while conventional IC PUFs are well-understood, several implementations have proven vulnerable to malicious exploits, including those perpetrated by machine learning (ML)-based attacks. Such attacks can be difficult to prevent because they are often designed to work even when relatively few challenge-response pairs are known in advance. Hence the need for both more resilient PUF designs and analysis of ML-attack susceptibility. Previous work has developed a PUF for photonic integrated circuits (PICs). A PIC PUF not only produces unpredictable responses given manufacturing-introduced tolerances, but is also less prone to electromagnetic radiation eavesdropping attacks than a purely electronic IC PUF. In this work, we analyze the resilience of the proposed photonic PUF when subjected to ML-based attacks. Specifically, we describe a computational PUF model for producing the large datasets required for training ML attacks; we analyze the quality of the model; and we discuss the modeled PUF's susceptibility to ML-based attacks. We find that the modeled PUF generates distributions that resemble uniform white noise, explaining the exhibited resilience to neural-network-based attacks designed to exploit latent relationships between challenges and responses. Preliminary analysis suggests that the PUF exhibits similar resilience to generative adversarial networks, and continued development will show whether more-sophisticated ML approaches better compromise the PUF and -- if so -- how design modifications might improve resilience.Comment: 14 pages, 8 figure

Mortality and pulmonary complications in patients undergoing surgery with perioperative SARS-CoV-2 infection: an international cohort study

Background: The impact of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) on postoperative recovery needs to be understood to inform clinical decision making during and after the COVID-19 pandemic. This study reports 30-day mortality and pulmonary complication rates in patients with perioperative SARS-CoV-2 infection. Methods: This international, multicentre, cohort study at 235 hospitals in 24 countries included all patients undergoing surgery who had SARS-CoV-2 infection confirmed within 7 days before or 30 days after surgery. The primary outcome measure was 30-day postoperative mortality and was assessed in all enrolled patients. The main secondary outcome measure was pulmonary complications, defined as pneumonia, acute respiratory distress syndrome, or unexpected postoperative ventilation. Findings: This analysis includes 1128 patients who had surgery between Jan 1 and March 31, 2020, of whom 835 (74·0%) had emergency surgery and 280 (24·8%) had elective surgery. SARS-CoV-2 infection was confirmed preoperatively in 294 (26·1%) patients. 30-day mortality was 23·8% (268 of 1128). Pulmonary complications occurred in 577 (51·2%) of 1128 patients; 30-day mortality in these patients was 38·0% (219 of 577), accounting for 81·7% (219 of 268) of all deaths. In adjusted analyses, 30-day mortality was associated with male sex (odds ratio 1·75 [95% CI 1·28–2·40], p\textless0·0001), age 70 years or older versus younger than 70 years (2·30 [1·65–3·22], p\textless0·0001), American Society of Anesthesiologists grades 3–5 versus grades 1–2 (2·35 [1·57–3·53], p\textless0·0001), malignant versus benign or obstetric diagnosis (1·55 [1·01–2·39], p=0·046), emergency versus elective surgery (1·67 [1·06–2·63], p=0·026), and major versus minor surgery (1·52 [1·01–2·31], p=0·047). Interpretation: Postoperative pulmonary complications occur in half of patients with perioperative SARS-CoV-2 infection and are associated with high mortality. Thresholds for surgery during the COVID-19 pandemic should be higher than during normal practice, particularly in men aged 70 years and older. Consideration should be given for postponing non-urgent procedures and promoting non-operative treatment to delay or avoid the need for surgery. Funding: National Institute for Health Research (NIHR), Association of Coloproctology of Great Britain and Ireland, Bowel and Cancer Research, Bowel Disease Research Foundation, Association of Upper Gastrointestinal Surgeons, British Association of Surgical Oncology, British Gynaecological Cancer Society, European Society of Coloproctology, NIHR Academy, Sarcoma UK, Vascular Society for Great Britain and Ireland, and Yorkshire Cancer Research

Embedded Interests and the Managerial Local State: Methanol Fuel-Switching in China

This paper analyzes the determinants of alternative automobile fuel regulation and development support with a particular focus on methanol fuel. We find that embedded interests, bureaucratic reforms, and political circumstances in the Chinese national, provincial, and municipal governments have all shaped policy outcomes in this area. The paper seeks to explain why at, the national level, support for alternative fuels has waned and finds that the concerns of state oil majors and disorganization during the process of national bureaucratic restructuring have been the deciding factors. Interestingly, at the sub-national level promotion of methanol continues unabated in some places. At the local level, business relationships as well as the embedded economic and personal interests of local leaders help to explain managerial local government behavior and sheds light on why government officials actively create and manage methanol fuel business opportunities through local standardization, subsidies, and hands-on management of SOE opposition. The switch towards methanol fuel was more successful in localities where individuals, either government officials or enterprise managers, formed an alliance and made this their 'pet projects'. The analysis draws on 55 interviews conducted between June and October 2010 in Shanxi, a major coal-producing province which has supported methanol fuel-switching programs for over ten years. The findings contribute to debates about the condition of the local state in China. The argument put forward in this paper is that because of limited state capacity at the central level and insufficient concerns for the development of alternative fuels in the short-term, some sub-national governments with strong embedded interests promote certain alternative fuels by taking on active managerial roles, adopting creative and ad-hoc strategies to fill in the national level policy gap at the local level

Public Investment in University Distance Learning Programs: Some Performance-Based Evidence

H21, H41, J24,

Learning strategies in reading and writing: EAP contexts

Presently, the importance of culture and context is becoming a significant feature of research in the field of learning strategies. To date, there has been little research into learning strategies utilized for reading and writing in Asian EAP (English for Academic Purposes) contexts, and in particular in the Thai context. With this in mind, this research investigated learning strategies employed by undergraduate students at a Thai university studying EAP reading and writing courses. The research aimed to identify the most frequently used strategies and different strategy use between ‘successful’ and ‘less successful’ learners. Learning strategies were classified following Oxford’s (1990) six category taxonomy and an additional category of negative strategies. The results revealed metacognitive, cognitive and compensation as the most frequently used strategies overall. Differences in strategy use for successful and less successful readers and writers were also demonstrated. A number of affective and social strategies were identified in the quantitative analysis which needed further investigation. Furthermore, various strategies investigated in earlier learner strategy research seemed, based on this research, to be culturally inappropriate in the Thai context