Rajni Goel

Performance Analysis of Homing Pigeon based Delay Tolerant Networks

This paper presents and analyzes a new type of delay tolerant network where each node owns a dedicated messenger (called a pigeon). The only form of inter-node communication is for a pigeon to periodically carry a batch of messages originated at the home node, deliver them to the corresponding destination nodes and return home. Clearly, given message expiration times, some messages may not reach their destinations by the deadline. Through theoretical analysis and simulations, we study the relationship between the arrival rate (at the home node), batch size, expiration time and delivery ratio (the percentage of messages reaching destinations before they expire) of messages. The simplistic assumptions we make render the problem tractable, and help us gather experience in this topic.

Communications Based Positive Train Control Systems Architecture in the USA

The implementation of railroad PTC systems in the United States has been hindered by the lack of a suitable regulatory environment. Understanding implementation efforts have often been further hindered by lack of a clear understanding of the basic PTC architecture and functionality. This paper summarizes the recent regulatory change that supports the implementation of PTC in the United States. The final regulation poses its own challenge, especially when a government agency and a regulated industry need to make a transition from prescriptive-based to performance-based standards. However, the new regulations provide positive benefits over previous prescriptive approaches in implementing PTC. This paper describes basic PTC architectures and functionality being adopted in the railroad environment, and closes by highlighting two different implementations of the same basic PTC architecture

Using Real Datasets for Interdisciplinary Business/Economics Projects

The workplaces global and dynamic nature allows and requires improved approaches for providing business and economics education. In this article, the authors explore ways of enhancing students understanding of course material by using nontraditional, real-world datasets of particular interest to them. Teaching at a historically Black university, the authors used one such database, the ING Gazelle Index, which measures the business confidence of small, fast-growing African-American firms. Instructors reviewed student papers based on this Index and analyzed a postproject survey taken by the students. There are a variety of lesser-known economic indices and other data sources that can be used in a similar manner.

Key management requirements for Positive Train Control communications security

Positive Train Control (PTC) is an electronic system that enforces train separation, speed enforcement, roadway worker protection and a host of other activities essential to operate railroads safety and efficiently that requires wireless communication to exchange control and sensory information between mobile locomotive and static control centers and wayside devices. This requires communication security ensuring the freshness, confidentiality, integrity, and authenticity of the information. For that purpose, we propose a cryptography based key management system (KMS). This paper outlines the requirements for a KMS, provides a proposed key distribution method, and highlights several significant implementation tradeoffs

Key management requirements for PTC operations

Positive train control (PTC) is an electronic system that enforces activities such as train separation, speed enforcement, and roadway worker protection essential to operate railroads safely and efficiently. Vehicular ad-hoc networks (VANETS) provide distributed real time communication of traffic hazards and road conditions among vehicles in a radio line of sight. Communicating PTC VANET systems offer the potential to reduce highway rail intersection (HRI) collisions by communicating train movement information to highway vehicles. For this to occur, different PTC systems must securely interoperate with each other. This outlines a PTC security framework utilizing using a certificate based trust management system and over the air re-keying (OTAR) to support interoperation.

Communications Security Concerns in Communications Based Train Control

Since the late 1980s, Communication Based Train Control (CBTC) Systems for freight and passenger rail have been under development in the United States. These systems have been advertised as offering significant enhancements in safety by ensuring positive train separation, enforcing speed restrictions, and improving roadway worker protection. In order to maximize the effect of these safety enhancements, it is necessary for CBTC systems to address security issues common to wireless computer communication systems. This paper introduces the role that CBTC systems play in railroad methods of operations, as well as the vulnerabilities of communications systems being manifested in CBTC. It provides a classification of attacks against CBTC systems, and identifies the security controls to mitigate these attacks. The level of risks associated with these security issues have increased from the first CBTC system introduction, primary because of increases in the means of exploiting the associated vulnerabilities. Exploitation that could compromise the system safety capabilities can take the form of any number of different types of attacks (e.g. jamming, etc). Failure of the CBTC system designer to adequately address these attacks could allow a malicious party to exploit CBTC vulnerabilities, effectively neutralizing the safety advantages of a CBTC system. Recent non-CBTC train-to-train collisions causing release of toxic inhalants and resulting deaths illustrate that a lack of CBTC system safety capabilities could have catastrophic results. Fortunately, these attacks can be mitigated using various security controls. Understanding the attacks and the respective mitigating security mechanisms is therefore key to effectively implementing CBTC safety advantages.

Mapping Misuse Cases to Functional Fault Trees in order to Secure Positive Train Control Systems

Use cases specify the higher-level functional requirements of a system under design and misuse cases specify its possible misuses. Analyzing them together prevents the latter from occurring while ensuring that the former are implemented. Independently, functional fault trees (FFT) hierarchically breakdown anticipated system failures with respect to its functional architecture. This work presents and algorithm that transforms higher-level use-misuse case to FFTs, and thereby allows the application of the analytical methods available for the latter to the former. The utility of such a mechanism is illustrated by studying the security vulnerabilities that can be introduced to Positive Train Control (PTC) systems – wireless command and control systems for the safe operation of freight and passenger trains.

U.S. Federal Oversight of Rail Transportation of Toxic by Inhalation Materials

The 9/11 Commission created as a consequence of the terrorist attacks on New York City and Washington had two goals. The first goal was to study the incidents to determine the specific security failures; the second was to provide recommendations for preventing future incidents. In August 2007, President Bush signed U.S. Public Law 110-53 that implemented the 9/11 Commission recommendations. Section 1551 of the law requires every railroad carrier that transports security-sensitive materials in commerce to provide a written analysis of the safety and security risks for every calendar year. This paper discusses the background behind the current regulatory requirements, the nature of the security-sensitive materials involved, the rail industry and its role in the movement of security-sensitive materials, and the new U.S. federal regulatory requirements associated with the shipment of toxic by inhalation (TIH) materials.

SECURE CROSS-DOMAIN TRAIN SCHEDULING

Track configurations at cross-domain interchange points, train performance characteristics and cross-domain authentication often produce significant train delays that can impact large segments of a railroad network. This paper presents a model that captures the behavior of trains and the track infrastructure. The model enables railroad signal engineers to quickly estimate the required trust management system performance that will support safe, secure and efficient railroad operations.