Thomas M. Chen

Lessons from Stuxnet

The article mentions that the malware such as Stuxnet can affect critical physical infrastructures that are controlled by software, which implies that threats might extend to real lives. Stuxnet differs from past malware in several ways. First, most malware tries to infect as many computers as possible, whereas Stuxnet appears to target industrial control systems and delivers its pay load under very specific conditions. Second, Stuxnet is larger and more complex than other malware. It cotains exploits for four vulnerabilities.

Dempster-Shafer theory for intrusion detection in ad hoc networks

Without a fixed security infrastructure, mobile ad hoc networks must distribute intrusion detection among their nodes. But even though a distributed intrusion-detection system can combine data from multiple nodes to estimate the likelihood of an intrusion, the observing nodes-might not be reliable. The Dempster-Shafer theory of evidence is well suited for this type of problem because it reflects uncertainty. Moreover, Dempsters rule for combination gives a numerical procedure, for fusing together multiple pieces of evidence from unreliable observers. The authors review the Dempster-Shafer theory in the context of distributed intrusion detection and demonstrate the theorys usefulness.

Petri Net Modeling of Cyber-Physical Attacks on Smart Grid

This paper investigates the use of Petri nets for modeling coordinated cyber-physical attacks on the smart grid. Petri nets offer more flexibility and expressiveness than traditional attack trees to represent the actions of simultaneous attackers. However, Petri net models for attacks on very large critical infrastructures such as the smart grid require a great amount of manual effort and detailed expertise in cyber-physical threats. To overcome these obstacles, we propose a novel hierarchical method to construct large Petri nets from a number of smaller Petri nets that can be created separately by different domain experts. The construction method is facilitated by a model description language that enables identical places in different Petri nets to be matched. The new modeling approach is described for an example attack on smart meters, and its efficacy is demonstrated by a proof-of-concept Python program.

The available bit rate service for data in ATM networks

The authors describe the purpose of the available bit rate (ABR) service in the context of other ATM services and review the agreements on the traffic control mechanism. They describe the recent progress towards standardization of the new service. The general nature of the ABR service is described in comparison with constant bit rate (CBR) and variable bit rate (VBR) services.

Dynamic priority protocols for packet voice

Since the reconstruction of continuous speech from voice packets is complicated by the variable delays of the packets through the network, a dynamic priority protocol is proposed to minimize the variability of packet delays. The protocol allows the priority of a packet to vary with time. After a discussion of the concept of dynamic priorities, two examples of dynamic priorities are studied through queueing analysis and simulations. Optimal properties of the oldest customer first (OCF) and earliest deadline first (EDF) disciplines are proven, suggesting that they may be theoretically effective in reducing the variability of packet delays. Simulation results of the OCF discipline indicate that the OCF discipline is most effective under conditions of long routes and heavy traffic, i.e., the conditions when delay variability is most likely to be significant. Under OCF, the delays of packets along long routes are improved at the expense of packets along short routes. It is noted that more complex and realistic simulations, including simulations of the EDF discipline, are needed. >

Stuxnet, the real start of cyber warfare? [Editor's Note]

In recent years, the press has been banging the drums about the prospects of cyber warfare between nations. It makes a good story. In the imagined scenario, national governments are gathering and training elite teams of computer hackers prepared to infiltrate or take down the computer network of an enemy nation. Every nation has the weapons ? computers and software ? to be a major threat without having to be a superpower. Any David can take on a Goliath, and in fact the most industrialized countries might be the most network- dependent and vulnerable.

Worm epidemics in high-speed networks

Future worm epidemics might spread at unprecedented rates in high-speed networks. A comprehensive automated defense system will be the only way to contain new threats but could be too risky to implement without more reliable detection accuracy and better real-time traffic analysis. Although researchers continue to work on improving worm detection accuracy and real-time traffic analysis, a practical solution thus far remains elusive. One possible alternative is to try to prevent a worm from spreading rather than react to an existing epidemic.

Adaptive congestion control for DSRC vehicle networks

Dedicated short range communications (DSRC) was proposed for collaborative safety applications (CSA) in vehicle communications. In this article we propose two adaptive congestion control schemes for DSRC-based CSA. A cross-layer design approach is used with congestion detection at the MAC layer and traffic rate control at the application layer. Simulation results show the effectiveness of the proposed rate control scheme for adapting to dynamic traffic loads.

Integrated voice/data switching

A basic understanding of the technical problems in integrating voice and data is provided. The different types of traffic found in communication systems are examined. Integration is investigated at different levels. In particular, the focus is on the integration of voice and data at the switching level. Different switching approaches are compared and some integrated-switching systems are described.<<ETX>>

A Distributed Consensus Algorithm for Decision Making in Service-Oriented Internet of Things

In a service-oriented Internet of things (IoT) deployment, it is difficult to make consensus decisions for services at different IoT edge nodes where available information might be insufficient or overloaded. Existing statistical methods attempt to resolve the inconsistency, which requires adequate information to make decisions. Distributed consensus decision making (CDM) methods can provide an efficient and reliable means of synthesizing information by using a wider range of information than existing statistical methods. In this paper, we first discuss service composition for the IoT by minimizing the multi-parameter dependent matching value. Subsequently, a cluster-based distributed algorithm is proposed, whereby consensuses are first calculated locally and subsequently combined in an iterative fashion to reach global consensus. The distributed consensus method improves the robustness and trustiness of the decision process.