Ashlesh Sharma

Road traffic congestion in the developing world

Road traffic jams continue to remain a major problem in most cities around the world, especially in developing regions resulting in massive delays, increased fuel wastage and monetary losses. Due to the poorly planned road networks, a common outcome in many developing regions is the presence of small critical areas which are common hot-spots for congestion; poor traffic management around these hotspots potentially results in elongated traffic jams. In this paper, we first present a simple automated image processing mechanism for detecting the congestion levels in road traffic by processing CCTV camera image feeds. Our algorithm is specifically designed for noisy traffic feeds with poor image quality. Based on live CCTV camera feeds from multiple traffic signals in Kenya and Brazil, we show evidence of this congestion collapse behavior lasting long time-periods across multiple locations. To partially alleviate this problem, we present a local de-congestion protocol that coordinates traffic signal behavior within a small area and can locally prevent congestion collapse sustaining time variant traffic bursts. Based on a simulation based analysis on simple network topologies, we show that our local de-congestion protocol can enhance road capacity and prevent congestion collapse in localized settings.

Hermes: data transmission over unknown voice channels

While the cellular revolution has made voice connectivity ubiquitous in the developing world, data services are largely absent or are prohibitively expensive. In this paper, we present Hermes1, a point-to-point data connectivity solution that works by modulating data onto acoustic signals that are sent over a cellular voice call. The main challenge is that most voice codecs greatly distort signals that are not voice-like; furthermore, the backhaul can be highly heterogeneous and of low quality, thereby introducing unpredictable distortions. Hermes modulates data over the extremely narrow-band approximately 3kHz bandwidth) acoustic carrier, while being severely constrained by the requirement that the resulting sound signals are voice-like, as far as the voice codecs are concerned. Hermes uses a robust data transcoding and modulation scheme to detect and correct errors in the face of bit flips, insertions and deletions; it also adapts the modulation parameters to the observed bit error rate on the actual voice channel. Through real-world experiments, we show that Hermes achieves approximately 1.2 kbps goodput which when compared to SMS, improves throughput by a factor of 5× and reduces the cost-per-byte by over a factor of 50x

The case for SmartTrack

Nearly 40 million people in Africa suffer from HIV/AIDS. African governments and international aid agencies have been working to combat this epidemic by vigorously promoting Highly Active Anti-Retroviral Therapy (HAART) programs. Despite the enormous subsidies offered by governments along with free Anti-RetroViral (ARV) drugs supplied by agencies, the introduction and implementation of HAART programs on a large scale has been limited by two fundamental problems: (a) lack of adherence to the ARV therapy regimen; (b) lack of accountability in drug distribution due to theft, corruption and counterfeit medication. In this paper, we motivate the case for SmartTrack, a telehealth project which aims to address these two problems facing HAART programs. The goal of SmartTrack is to create a highly reliable, secure and ultra low-cost cellphone-based distributed drug information system that can be used for tracking the flow and consumption of ARV drugs in HAART programs. In this paper, we assess the potential benefit of SmartTrack using a detailed needs-assessment study performed in Ghana, using interviews with 516 HIV-positive rural patients in a number of locations across the country. We find that a system like SmartTrack would immensely benefit both patients and healthcare providers, and can ultimately lead to improved patient outcomes and better accountability.

Secure rural supply chain management using low cost paper watermarking

Supply chain systems in rural developing regions are extremely fragile and are vulnerable to a wide range of security threats including theft, fraud and counterfeit goods. In this paper, we propose the design of a secure, low cost supply chain management system that leverages cheap cellphones and a low-cost paper watermarking system that can authenticate and verify the integrity of goods in a supply chain. Unlike many sophisticated solutions which have deployment problems due to the harsh ground realities in rural regions, our system is easy to use, deploy and does not require significant changes to the existing operational model. In addition, our system relies only on paper and cellphones, both of which are ubiquitously used in rural developing regions.

Microscopic paper fingerprinting

Financial systems, health care, governance, and other related markets use paper as the primary medium of communication. Therefore, verifying the authenticity of a piece of paper or document is of paramount importance. Counterfeiting and forgery of paper documents are a massive problem worldwide, with losses ranging in billions of dollars. We have developed a low-cost microscope system to authenticate paper that works across a wide variety of scenarios. Research efforts in the area of paper fingerprinting range from techniques that try to understand the fiber structure1 or the randomness of ink splatters made by a printer to extract a unique sign,2 to mid-range scanners to model the 3D fiber structure,3 or lasers to model surface scattering.4 However, these approaches are either expensive, insufficiently robust, or cater to a limited set of applications. Our work differs from these approaches in two fundamental ways. First, the physical property that we use to fingerprint the paper is very different from existing solutions and superior because it is robust to tampering and environmental effects. Second, in contrast to bulky equipment such as scanners and laser surface authentication devices, we use a portable, handheld microscope to obtain a speckle pattern suited to a variety of scenarios. For instance, it can be used to authenticate paper checks and legal documents in a low-cost manner. Our system works both on a desktop/laptop and a cell phone. The concept of laser speckles has been around since the 1970s and is used in profiling objects.5 The ‘PaperSpeckle’ system we have developed is based on texture speckles.6 When light falls onto an object, it is scattered by the object’s texture and underlying physical non-uniformities. When projected onto a screen, this light produces unique bright and dark regions (see Figure 1). We use two types of devices to capture texture speckles. One is a handheld digital microscope with inbuilt partially coherent light sources (LEDs) and an imaging system that is attached to a desktop/laptop. The other device is a microscope that fits to the camera of a cell phone using a custom-built attachment. The Figure 1. Four different types of texture speckle patterns.

Alphacodes: Usable, Secure Transactions with Untrusted Providers using Human Computable Puzzles

Many banking and commerce payment systems in developing regions require users to share private or sensitive information in clear-text with untrusted providers, exposing them to different forms of man-in-the-middle attacks. In this paper, we introduce Alphacodes, a new paradigm that enables users to secure transactions with untrusted parties using the notion of human-computable visual puzzles. We describe how Alphacodes can be applied in different use cases and also explain two simple applications that we have built using this framework. We motivate our solution using security vulnerabilities in existing systems, and show how our protocol overcomes them. We demonstrate the ease of use of Alphacodes with minimal training using two simple crowdsourcing studies. Using another simple real world user study involving 10 users who speak Kannada (a regional Indian language), we show that the Alphacodes paradigm can be easily extended to languages beyond English.