Papers by Anura Jayasumana
Asynchronous stochastic discrete event based processes are commonplace in application domains suc... more Asynchronous stochastic discrete event based processes are commonplace in application domains such as social science, homeland security, and health informatics. Modeling complex interactions of such event data via marked temporal point processes (MTPPs) provides the ability of detection and prediction of specific interests or profiles. We present a novel multi-category MTPP generation technique for applications where training datasets are inherently sparse, incomplete, and small. The proposed adversarial architecture augments adversarial autoencoder (AAE) with feature mapping techniques, which includes a transformation between the categories and timestamps of marked points and the percentile distribution of the particular category. The transformation of training data to the distribution facilitates the accurate capture of underlying process characteristics despite the sparseness and incompleteness of data. The proposed method is validated using several benchmark datasets. The similarity between actual and generated MTPPs is evaluated and compared with a Markov process based baseline. Results demonstrate the effectiveness and robustness of the proposed technique.
IEEE Transactions on Very Large Scale Integration Systems, 1993
Abstract Combining the advantages of CMOS and bipolar, BiCMOS is emerging as a major technology f... more Abstract Combining the advantages of CMOS and bipolar, BiCMOS is emerging as a major technology for many high performance digital and mixed signal applications. Recent investigations revealed that bridging faults can be a major failure mode in IC's. Effects of bridging faults in BiCMOS circuits are presented. Bridging faults between logical units without feedback and logical units with feedback are considered. Several bridging faults can be detected by monitoring the power supply current (I (sub DDQ) monitoring). Effects of ...
IEEE Transactions on Very Large Scale Integration Systems, 1993
Abstract Combining the advantages of CMOS and bipolar, BiCMOS is emerging as a major technology f... more Abstract Combining the advantages of CMOS and bipolar, BiCMOS is emerging as a major technology for many high performance digital and mixed signal applications. Recent investigations revealed that bridging faults can be a major failure mode in IC's. Effects of bridging faults in BiCMOS circuits are presented. Bridging faults between logical units without feedback and logical units with feedback are considered. Several bridging faults can be detected by monitoring the power supply current (I (sub DDQ) monitoring). Effects of ...
Lecture Notes in Computer Science, 2017
Distributed Denial of Service (DDoS) attacks remain one of the most serious threats on the Intern... more Distributed Denial of Service (DDoS) attacks remain one of the most serious threats on the Internet. Combating such attacks to protect the victim and network infrastructure requires a distributed realtime defense mechanism. We propose Responsive Point Identification using Hop distance and Attack estimation rate (RPI-HA) that when deployed is able to filter out attack traffic and allow legitimate traffic in the event of an attack. It dynamically activates detection and blocks attack traffic while allowing legitimate traffic, as close to the source nodes as possible so that network resources are not wasted in propagating the attack. RPI-HA identifies the most effective points in the network where the filter can be placed to minimize attack traffic in the network and maximize legitimate traffic for the victim during the attack period. Extensive OPNET c based simulations with a real network topology and CAIDA attack data set shows that the method is able to place all filtering routers within three routers of the attacker nodes and stop 95% of attack traffic while allowing 77% of legitimate traffic to reach victim node.
Computer Communications, Dec 1, 1997
Register insertion bus (RIB) is a high-speed network that uses a folded-bus topology and a medium... more Register insertion bus (RIB) is a high-speed network that uses a folded-bus topology and a medium access interface similar to that used in the register insertion ring. A detailed analysis of the packet delay for the RIB network is presented. The analysis results are demonstrated and shown to accurately match RIB simulation results. Performance analysis demonstrates that fair network access is achieved at normal loads, but upstream stations are favored for high loads. Thus, extensions to the RIB access scheme to provide a fair distributed access scheme is presented. Results presented show this bandwidth balancing technique to provide a fair access to the network for all loads. 0 1997 Elsevier Science B.V.
Acoustical imaging, 1984
Extensive work has been done on medical ultrasonic imaging. Echocardiography is very us6ful in de... more Extensive work has been done on medical ultrasonic imaging. Echocardiography is very us6ful in detecting intracardiac thrombus. However, the pulse-echo technique suffers from a rather high incidence of false positive diagnoses due to the backscatter and attenuation. The reflected ultrasound signal from a target by the conventional ultrasound pulse-echo technique, such as the B-scan, is determined by the reflection coefficient at the interface as well as the attenuation of the substance along the path. It is therefore impossible to retrieve these two types of information separately by the knowledge of a single reflected signal. Additional information is required to separate the two types of information. The work reported here is the development of a method to obtain the necessary information by a second reflected signal from the opposite side of the object.
Virtual Coordinate (VC) based Wireless Sensor Networks (WSNs) are susceptible to attacks resultin... more Virtual Coordinate (VC) based Wireless Sensor Networks (WSNs) are susceptible to attacks resulting from malicious modification of VCs of individual nodes. While the impact of some such attacks is localized, others such as coordinate deflation and wormholes (tunneling) can cause severe disruptions. A comprehensive solution for detection of such attacks is presented that combines Beta Reputation System and a reputation based routing scheme. Latter ensures safe communication that bypasses malicious nodes during detection process. Attacks are identified by detecting changes in shape of network using topology maps. The topology distortion is rated using clusters identifiable by existing VCs thus requiring low computation and communication overhead. Simulation based evaluations demonstrate that the scheme efficiently detects deflation and wormhole attacks. The detection scheme easily differentiates between the changes in the network due to node failures, e.g., caused by battery drain, from those due to an attack.
Photonic Network Communications, Apr 17, 2008
An analytical model is derived to evaluate the performance of an optical switch using a feed-forw... more An analytical model is derived to evaluate the performance of an optical switch using a feed-forward fiber delay line (FDL) per output for contention resolution. Two different forwarding algorithms for the switch are presented and evaluated: a simple forwarding algorithm (SFA) that is easier to implement, and an enhanced algorithm that provides better performance in terms of both packet loss probability and packet delay. The analytical model can be utilized with both packet and burst switching schemes to characterize the performance of the proposed architecture. Results show that the proposed architecture reduces the packet loss probability compared to that without FDLs. Finally, the same architecture is shown to be capable of supporting Quality of Service (QOS).
EAI/Springer Innovations in Communication and Computing, Aug 23, 2018
Driven by increasing potency and decreasing cost/size of electronic devices capable of sensing, a... more Driven by increasing potency and decreasing cost/size of electronic devices capable of sensing, actuating, processing, and wirelessly communicating, the Internet of Things (IoT) is expected to expand into manufacturing plants, complex structures, and harsh environments. Subnets of simple devices ranging from smart RFIDs and tiny sensors/actuators deployed in massive numbers in 2D and complex 3D physical spaces will be key constituents of this infrastructure. Knowing the position of different devices within such networks is essential for the higher-level applications as well as networking functions. Measuring the physical distances and obtaining geographical coordinates of these devices become very costly, unreliable, or even infeasible for many IoT networks, particularly those deployed in harsh and complex environments that affect distance estimates and other measurements. Virtual coordinate systems (VCS) overcome such limitations and provide a viable alternative to geographic coordinates for many networking applications. They do not rely on received signal strength indicator (RSSI) or time delay, measurement of which is difficult and unreliable. Instead, VCSs use parameters such as connectivity or packet losses to develop coordinate systems which provide the basis for network operations such as self-organization, routing, and topology control. We provide a survey of these VCSs. Four main classes of VCS are defined: coordinate systems based on an embedded graph/tree topology, coordinate systems based on hop distances to a set of anchors, topological coordinate systems, and coordinate systems based on network properties. In addition to that, network operations such as routing based on different coordinate schemes are presented.
WNM this year will continue to be a forum for researchers and practitioners interested in network... more WNM this year will continue to be a forum for researchers and practitioners interested in network measurements to discuss measurement related research and technology and exchange data. Network measurements, for both wireless and wired domains, continue to remain crucial for operation, diagnosis and characterization of complex networks. Emerging overlay networks that provide users the ability to overcome limitations of individual providers or networks also rely to a large degree on measurement based estimation of conditions of underlying networking infrastructure. Accurate characterization is important for understanding the behavior of networks and for evaluating the scalability, reliability and performance of protocols. Complex dynamics of the networks and also the difficulties in performing measurement itself pose many challenges. Thus it is exciting to have a group of researchers and practitioners in the area to exchange ideas about this important topic. We thank you for making this meeting a success and look forward to suggestions and comments for further improvements in future. Conference Chairs
IEE proceedings, 1995
Colorado State University A Detailed Anal ysi s on the Mani festationsof Faul ts i n Si ngl e and... more Colorado State University A Detailed Anal ysi s on the Mani festationsof Faul ts i n Si ngl e and D o u bl e BJT Bi C M OS Logi cGates 3 Sankaran M. M enon Anur a P. J a y asumana Yas hwant K. M alaiya y Dept. of Elect rical E ngi neeri ng, y D ept. o f C o mput er Sci ence C ol o rado St a t eU n i versi t y Ft. C ol l i n s, C O 80523
Proceedings of SPIE, Jul 3, 2002
In recent past we have witnessed the migration of the Internet from a classic computer communicat... more In recent past we have witnessed the migration of the Internet from a classic computer communication infrastructure to a platform for multimedia applications. Several new approaches have appeared and many protocols have been presented in order to accomplish this transformation. However many challenges remain, especially in the provision of quality of service (QoS). We present and evaluate new techniques and combinations of other well-known QoS mechanism to achieve end-to-end QoS for real-time applications. We propose a priority disciplines for Differential Services architectures and evaluate it in detail for mixed traffic including streams that use conventional protocols such as UDP or TCP and others that are targeted for real-time applications such as RTP. Next we present new brokering concepts at the boundary of the DS-Domain. We present two new dynamic Service Level Agreement methods that will help us accomplish our end-to-end delay minimization goal. These new approaches reduce the connection and/or re-connection time expended by the server during the agreement process with the DS-entry nodes. Finally we include a QoS routing mechanism in our system and map its features to the DS-domain characteristics
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Papers by Anura Jayasumana