We have developed HandMATE (Hand Movement Assisting Therapy Exoskeleton); a wearable motorized hand exoskeleton for home-based movement therapy following stroke. Each finger and the thumb is powered by a linear actuator which provides flexion and extension assistance. Force sensitive resistors integrated into the design measure grasp and extension initiation force. An assistive therapy mode is based on an admittance control strategy. We evaluated our control system via subject and bench testing. Errors during a grip force tracking task while using the HandMATE were minimal (<1%) and comparable to unassisted healthy hand performance. We also outline a dedicated app we have developed for optimal use of HandMATE at home. The exoskeleton communicates wirelessly with an Android tablet which features guided exercises, therapeutic games and performance feedback. We surveyed 5 chronic stroke patients who used the HandMATE device to further evaluate our system, receiving positive feedback on the exoskeleton and integrated app.

This paper proposes using a logic programming language to disentangle X.509 certificate validation policy from mechanism. Expressing validation policies in a logic programming language provides multiple benefits. First, policy and mechanism can be more independently written, augmented, and analyzed compared to the current practice of interweaving them within a C or C++ implementation. Once written, these policies can be easily shared and modified for use in different TLS clients. Further, logic programming allows us to determine when clients differ in their policies and use the power of imputation to automatically generate interesting certificates, e.g., a certificate that will be accepted by one browser but not by another.We present a new framework called Hammurabi for expressing validation policies, and we demonstrate that we can express the complex policies of the Google Chrome and Mozilla Firefox web browsers in this framework. We confirm the fidelity of the Hammurabi policies by comparing the validation decisions they make with those made by the browsers themselves on over ten million certificate chains derived from Certificate Transparency logs, as well as 100K synthetic chains. We also use imputation to discover nine validation differences between the two browsers' policies. Finally, we demonstrate the feasibility of integrating Hammurabi into Firefox and the Go language in less than 100 lines of code each. CCS CONCEPTS• Security and privacy → Web protocol security; Logic and verification.