Search Results

You are looking at 1 - 3 of 3 items for

  • Author: Anupam Das x
Clear All Modify Search
Open access

Anupam Dutta and Anup Kumar Das

Abstract

VELSEAL-Tis an innovative haemostatic medical device for the control of bleeding. Incorporating a clotting agent (thrombin) and anti-fibrinolytic agent (tranexamic acid), it enables rapid coagulation when blood flows into the dressing, leading to sealing and stabilisation of wound surfaces. A 36-year-old known to have mild haemophilia A presented with profuse bleeding from the forehead after injury following a fall on concrete surface. He attended hospital after 18 hours of injury as bleeding continued as soon as pressure was released from the injury site. A VELSEAL-T patch was applied to the injury site with the patient’s full consent. The bleeding stopped after 60 seconds, but the patient was instructed to hold the patch in place for a further 60 seconds. After two minutes of tight pressure application, there was no more oozing of blood from the injury site. This case shows that VELSEAL-T can be used as an aid in stopping external bleeding in haemophilia patients. Further trials should be undertaken to evaluate the safety and efficacy of this product.

Open access

Anupam Das, Nikita Borisov and Edward Chou

Abstract

The ability to track users’ activities across different websites and visits is a key tool in advertising and surveillance. The HTML5 DeviceMotion interface creates a new opportunity for such tracking via fingerprinting of smartphone motion sensors. We study the feasibility of carrying out such fingerprinting under real-world constraints and on a large scale. In particular, we collect measurements from several hundred users under realistic scenarios and show that the state-of-the-art techniques provide very low accuracy in these settings. We then improve fingerprinting accuracy by changing the classifier as well as incorporating auxiliary information. We also show how to perform fingerprinting in an open-world scenario where one must distinguish between known and previously unseen users.

We next consider the problem of developing fingerprinting countermeasures; we evaluate the usability of a previously proposed obfuscation technique and a newly developed quantization technique via a large-scale user study. We find that both techniques are able to drastically reduce fingerprinting accuracy without significantly impacting the utility of the sensors in web applications.

Open access

Joshua Juen, Aaron Johnson, Anupam Das, Nikita Borisov and Matthew Caesar

Abstract

The Tor anonymity network has been shown vulnerable to traffic analysis attacks by autonomous systems (ASes) and Internet exchanges (IXes), which can observe different overlay hops belonging to the same circuit. We evaluate whether network path prediction techniques provide an accurate picture of the threat from such adversaries, and whether they can be used to avoid this threat. We perform a measurement study by collecting 17.2 million traceroutes from Tor relays to destinations around the Internet. We compare the collected traceroute paths to predicted paths using state-of-the-art path inference techniques. We find that traceroutes present a very different picture, with the set of ASes seen in the traceroute path differing from the predicted path 80% of the time. We also consider the impact that prediction errors have on Tor security. Using a simulator to choose paths over a week, our traceroutes indicate a user has nearly a 100% chance of at least one compromise in a week with 11% of total paths containing an AS compromise and less than 1% containing an IX compromise when using default Tor selection. We find modifying the path selection to choose paths predicted to be safe lowers total paths with an AS compromise to 0.14% but still presents a 5–11% chance of at least one compromise in a week while making 5% of paths fail, with 96% of failures due to false positives in path inferences. Our results demonstrate more measurement and better path prediction is necessary to mitigate the risk of AS and IX adversaries to Tor.