Efficient communication protection of many-core systems against active attackers

Many-core system-on-chips, together with their established communication infrastructures, Networks-on-Chip (NoC), are growing in complexity, which encourages the integration of third-party components to simplify and accelerate production processes. However, this also adversely exposes the surface for attacks through the injection of hardware Trojans. This work addresses active attacks on NoCs and focuses on the integrity and availability of transmitted data. In particular, we consider the modification and/or dropping of data during transmission as active attacks that might be performed by malicious routers. To mitigate the impact of such active attacks, we propose two lightweight solutions that respect the performance constraints of NoCs. Assuming the presence of symmetric keys, these approaches combine lightweight authentication codes for integrity protection with network coding for increased efficiency and robustness. The proposed solutions prevent undetected modifications and significantly increase availability through a reliable detection of attacks. The efficiency of these solutions is investigated in different scenarios using cycle-accurate simulations and the area overhead is analyzed relative to state-of-the-art many-core system. The results demonstrate that one authentication scheme with network coding protects the integrity of data to a low residual error of 1.36% at 0.2 attack probability with an area overhead of 2.68%. For faster and more flexible evaluation, an analytical approach is developed which is validated against the cycle-accurate simulations. The analytical approach is more than 1000× faster while having a maximum estimation error of 5%. Moreover, the analytical model provides a deeper insight into the system’s behavior. For example, it reveals which factors influence the performance parameters

Acid Catalyzed Competitive Esterification and Ketalization of Levulinic Acid with 1,2 and 1,3-Diols: The Effect of Heterogeneous and Homogeneous Catalysts

Abstract: Condensation reactions of levulinic acid (LA) with 1,2-ethanediol (1,2-ED), 1,2-propanediol (1,2-PD), and 1,3-propanediol (1,3-PD) were studied using Amberlyst-15 as well as p-toluenesulfonic acid catalysts in benzene under Dean–Stark conditions. In Amberlyst-15 catalyzed reactions the products are ketals and ketal-esters, whereas p-toluenesulfonic acid catalyzed reactions produce esters and ketal-esters as products. In p-toluenesulfonic acid catalyzed reactions with 1,2-ED and 1,3-PD, LA monoester product is formed as the major product after 180 min in 75 and 97 % yields respectively. Unlike the previously reported acid catalyzed ketalization of ethyl levulinate with diols, combined ketalization–esterification of LA with diols is a complex process. Graphical Abstract: [Figure not available: see fulltext.

Neck circumference as a marker of overweight and obesity and cutoff values for Bangladeshi adults

Objective: There are several methods of assessing overweight and obesity. Several studies conducted in different populations indicate that neck circumference (NC) can be used as a simple measure of overweight and obesity. This study was conducted to evaluate NC as a marker of overweight and obesity and to determine respective cutoff values for Bangladeshi male and female participants. Research Design/Materials and Methods: This cross-sectional observational study was conducted with during July 2013–June 2014 among randomly selected 871 Bangladeshi participants (male = 496 [56.9%], female = 375 [43.1%], aged >18 years) who visited Outpatient Department of United Hospital, Bangladesh Institute of Research and Rehabilitation in Diabetes, Endocrine and Metabolic disorders, primary health-care centers located in Dhaka, Savar, Gazipur. NC of participants was taken in centimeter to the nearest 1 mm, using plastic tape measure. Main outcome included NC, waist circumferences (WC), body mass index (BMI), and waist: hip ratio (WHR). Results: Pearson's correlation coefficients indicated a significant association between NC and height (men, r = 0.33; women, r = 0.28; P 90 cm in men and > 80 cm in women, respectively. NC ≥34.45 cm in male (AUC: 0.59; P= 0.001) and NC ≥31.25 cm in women (AUC: 0.66; P = 0.008) were the best cutoff value for WHR >0.9 in men and >0.8 in women, respectively. Conclusion: NC measurement is a simple, convenient, inexpensive screening measure to identify overweight and obese participants. Men with NC ≥34.75 cm and women with NC ≥31.75 cm are to be considered overweight while men with NC ≥35.25 cm and women with NC ≥34.25 cm are to be considered obese. NC ≥35.25 cm in male and NC ≥31.25 cm in women were the best cutoff value for abdominal obesity