No abstract

Raising the rotational speed of electro-hydrostatic actuator (EHA) pumps is a useful way to improve their power density. However, gaseous cavitation tends to occur in the displacement chambers at high speed, reducing the effective delivery flow rate of EHA pumps. It is a common approach to reduce the gaseous cavitation by increasing the inlet pressure. However, this conventional approach requires additional devices to boost the inlet line, which decreases the EHA pump's power density. The contribution of this study is to reduce the gaseous cavitation by introducing inclined cylinder block ports for EHA pumps, which only modifies the cylinder ports and needs no additional devices. A computational fluid dynamics (CFD) model was developed to investigate the effects of the inclined direction of cylinder ports on the gaseous cavitation. The simulation results showed that the inwardinclined design of cylinder ports could effectively decrease the gaseous cavitation using centrifugal effects of rotating fluid. Compared with a standard cylinder block, the cylinder block with inwardinclined ports could increase the effective delivery flow rate by 4% at an inlet pressure of 1 MPa and a rotational speed of 20,000 r/min. ARTICLE HISTORY

Software Guard Extension (SGX) is a hardware-based trusted execution environment (TEE) implemented in recent Intel commodity processors. By isolating the memory of security-critical applications from untrusted software, this mechanism provides users with a strongly shielded environment called enclave for executing programs safely. However, recent studies have demonstrated that SGX enclaves are vulnerable to side-channel attacks. In order to deal with these attacks, several protection techniques have been studied and utilized.In this paper, we explore a new pattern history table (PHT) based side-channel attack against SGX named Bluethunder, which can bypass existing protection techniques and reveal the secret information inside an enclave. Comparing to existing PHT-based attacks (such as Branchscope [ERAG+18]), Bluethunder abuses the 2-level directional predictor in the branch prediction unit, on top of which we develop an exploitation methodology to disclose the input-dependent control flow in an enclave. Since the cost of training the 2-level predictor is pretty low, Bluethunder can achieve a high bandwidth during the attack. We evaluate our attacks on two case studies: extracting the format string information in the vfprintf function in the Intel SGX SDK and attacking the implementation of RSA decryption algorithm in mbed TLS. Both attacks show that Bluethunder can recover fine-grained information inside an enclave with low training overhead, which outperforms the latest PHT-based side channel attack (Branchscope) by 52×. Specifically, in the second attack, Bluethunder can recover the RSA private key with 96.76% accuracy in a single run.

Cypermethrin resistance in the German cockroach, Blattella germanica (L.), was assessed by tests of surface contact and topical application. Topical application provided the most sensitive measure of resistance in a field strain. The resistance ratio (RR) measured by topical application was 122.6 for cypermethrin at LD50. As measured by surface contact, the resistance ratio at KT50 was 2.9. Differences between the walking movement of cockroaches of susceptible (VPI) and field (RHA) strains on deposits of cypermethrin influenced KT50 values. A bioassay with unrestricted movement resulted in RHA strain cockroaches accumulating a larger dose on the tarsal pads and subsequent reduction of the resistance ratio at KT50. Less walking by the VPI strain resulted in less insecticide accumulation on their tarsal pads. On a bioassay in which movement was restricted, the amount of insecticide accumulating on the tarsi was equalized, resulting in an increased resistance ratio at KT50. Differences in susceptibility were more accurately measured when the two strains were topically treated (either on the thorax or the tarsal pads) with known doses of insecticide.