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Full-Text Articles in Physical Sciences and Mathematics

Experiments To Assess The Cost-Benefits Of Test-Suite Reduction, Gregg Rothermel, Mary Jean Harrold, Jeffery Von Ronne, Christie Hang, Jeffery Ostrin Dec 1999

Experiments To Assess The Cost-Benefits Of Test-Suite Reduction, Gregg Rothermel, Mary Jean Harrold, Jeffery Von Ronne, Christie Hang, Jeffery Ostrin

CSE Technical Reports

Test-suite reduction techniques attempt to reduce the cost of saving and reusing test cases during software maintenance by eliminating redundant test cases from test suites. A potential drawback of these techniques is that in reducing a test suite they might reduce the ability of that test suite to reveal faults in the software. Previous studies suggested that test-suite reduction techniques can reduce test suite size without significantly reducing the fault-detection capabilities of test suites. To further investigate this issue we performed experiments in which we examined the costs and benefits of reducing test suites of various sizes for several programs …


Impact Of Transmission Impairments On The Teletraffic Performance Of Wavelength-Routed Optical Networks, Byrav Ramamurthy, Debasish Datta, Helena Feng, Jonathan P. Heritage, Biswanath Mukherjee Oct 1999

Impact Of Transmission Impairments On The Teletraffic Performance Of Wavelength-Routed Optical Networks, Byrav Ramamurthy, Debasish Datta, Helena Feng, Jonathan P. Heritage, Biswanath Mukherjee

School of Computing: Faculty Publications

In a wavelength-routed optical network, a transmitted signal remains in the optical domain over the entire route (lightpath) assigned to it between its source and destination nodes. The optical signal may have to traverse a number of crossconnect switches (XCS’s), fiber segments, and optical amplifiers, e.g., erbium-doped fiber amplifiers (EDFA’s). Thus, while propagating through the network, the signal may degrade in quality as it encounters crosstalk at the XCS’s and also picks up amplified spontaneous emission (ASE) noise at the EDFA’s. Since these impairments continue to degrade the signal quality as it progresses toward its destination, the received bit error …


The Rate-Based Execution Model, Kevin Jeffay, Steve Goddard Apr 1999

The Rate-Based Execution Model, Kevin Jeffay, Steve Goddard

CSE Technical Reports

We present a new task model for the real-time execution of event-driven tasks in which no a priori characterization of the actual arrival rates of events is known; only the expected arrival rates of events is known. We call this new task model rate-based execution (RBE), and it is a generalization of the common sporadic task model. The RBE model is motivated naturally by distributed multimedia and digital signal processing applications.
We identify necessary and sufficient conditions for determining the feasibility of an RBE task set, and an optimal scheduling algorithm (based on preemptive earliest-deadline-first (EDF) scheduling) for scheduling the …


Segmentation Of Satellite Imagery Of Natural Scenes Using Data Mining, Leen-Kiat Soh, Costas Tsatsoulis Mar 1999

Segmentation Of Satellite Imagery Of Natural Scenes Using Data Mining, Leen-Kiat Soh, Costas Tsatsoulis

School of Computing: Faculty Publications

In this paper, we describe a segmentation technique that integrates traditional image processing algorithms with techniques adapted from knowledge discovery in databases (KDD) and data mining to analyze and segment unstructured satellite images of natural scenes. We have divided our segmentation task into three major steps. First, an initial segmentation is achieved using dynamic local thresholding, producing a set of regions. Then, spectral, spatial, and textural features for each region are generated from the thresholded image. Finally, given these features as attributes, an unsupervised machine learning methodology called conceptual clustering is used to cluster the regions found in the image …


Texture Analysis Of Sar Sea Ice Imagery Using Gray Level Co-Occurrence Matrices, Leen-Kiat Soh, Costas Tsatsoulis Mar 1999

Texture Analysis Of Sar Sea Ice Imagery Using Gray Level Co-Occurrence Matrices, Leen-Kiat Soh, Costas Tsatsoulis

School of Computing: Faculty Publications

This paper presents a preliminary study for mapping sea ice patterns (texture) with 100-m ERS-1 synthetic aperture radar (SAR) imagery. We used gray-level co-occurrence matrices (GLCM) to quantitatively evaluate textural parameters and representations and to determine which parameter values and representations are best for mapping sea ice texture. We conducted experiments on the quantization levels of the image and the displacement and orientation values of the GLCM by examining the effects textural descriptors such as entropy have in the representation of different sea ice textures. We showed that a complete gray-level representation of the image is not necessary for texture …


A Unifying Framework Supporting The Analysis And Development Of Safe Regression Test Selection Techniques, John Bible, Gregg Rothermel Jan 1999

A Unifying Framework Supporting The Analysis And Development Of Safe Regression Test Selection Techniques, John Bible, Gregg Rothermel

CSE Technical Reports

Safe regression test selection (RTS) techniques let software testers reduce the number of test cases that need to be rerun to revalidate new versions of software, while ensuring that no fault-revealing test case (in the existing test suite) is excluded. Most previous work on safe regression test selection has focused on specific safe RTS algorithms, rather than addressing the theoretical foundations of safe RTS techniques in general. In this paper, we present a unifying framework for safe RTS that supports the analysis and development of safe RTS techniques. We show that every safe RTS technique is founded on a regression …


Empirical Computation Of Reject Ratio In Vlsi Testing, Shashank K. Mehta, Sharad C. Seth Jan 1999

Empirical Computation Of Reject Ratio In Vlsi Testing, Shashank K. Mehta, Sharad C. Seth

CSE Conference and Workshop Papers

Among significant components of testing cost are testlength, reject ratio, and lost-yield. In this paper a new approach is proposed to estimate the reject ratio. The empirical model is based on test-data properties that are believed to be invariant for a wide range of manufacturing technologies and types of tests. The analysis is carried out entirely in terms of the device test data, as might be available from wafer probe. Experimental results demonstrate robustness of the model.


Cooperative Text And Line Art Extraction From A Topographic Map, Luyang Li, George Nagy, Ashok Samal, Sharad C. Seth, Yihong Xu Jan 1999

Cooperative Text And Line Art Extraction From A Topographic Map, Luyang Li, George Nagy, Ashok Samal, Sharad C. Seth, Yihong Xu

CSE Conference and Workshop Papers

The black layer is digitized from a USGS topographic map digitized at 1000 dpi. The connected components of this layer are analyzed and separated into line art, text, and icons in two passes. The paired street casings are converted to polylines by vectorization and associated with street labels from the character recognition phase. The accuracy of character recognition is shown to improve by taking account of the frequently occurring overlap of line art with street labels. The experiments show that complete vectorization of the black line-layer bitmap is the major remaining problem.


Comparison Of Scalable Key Distribution Schemes For Secure Group Communication, Lakshminath R. Dondeti, Sarit Mukherjee, Ashok Samal Jan 1999

Comparison Of Scalable Key Distribution Schemes For Secure Group Communication, Lakshminath R. Dondeti, Sarit Mukherjee, Ashok Samal

CSE Conference and Workshop Papers

Scalable secure key distribution is the most important feature of a scalable secure group communication protocol. Most of the existing scalable secure group communication protocols are based on a hierarchical key distribution tree. These schemes can be classified as hierarchical node based schemes and hierarchical key based schemes. In this paper; we compare recently proposed hierarchical key distribution schemes through simulation using real-life multicast group membership traces. Our simulations show that hierarchical node based approaches better distribute encryption cost among the entities of a multicast group. However hierarchical node based schemes “trust” internal nodes of a key distribution tree. We …


Routing And Wavelength Assignment (Rwa) With Power Considerations In All- Optical Wavelength-Routed Networks, Maher Ali, Byrav Ramamurthy, Jitender S. Deogun Jan 1999

Routing And Wavelength Assignment (Rwa) With Power Considerations In All- Optical Wavelength-Routed Networks, Maher Ali, Byrav Ramamurthy, Jitender S. Deogun

CSE Conference and Workshop Papers

Routing and wavelength assignment (RWA) is an important problem that arises in wavelength division multiplexed (WDM) optical networks. Previous studies have solved many variations of this problem under the assumption of perfect conditions regarding the power of a signal. In this paper, we investigate this problem while allowing for degradation of routed signals by components such as taps, multiplexers, and fiber links. We assume that optical amplifiers are preplaced. We investigate the problem of routing the maximum number of connections while maintaining proper power levels. The problem is formulated as a mixed-integer nonlinear program and two-phase hybrid solution approaches employing …


Transition From Research To Operations: Arktos - A Knowledge-Based Sea Ice Classification System, Cheryl Bertoia, Denise Gineris, Kim Partington, Leen-Kiat Soh, Costas Tsatsoulis Jan 1999

Transition From Research To Operations: Arktos - A Knowledge-Based Sea Ice Classification System, Cheryl Bertoia, Denise Gineris, Kim Partington, Leen-Kiat Soh, Costas Tsatsoulis

CSE Conference and Workshop Papers

ARKTOS is a fully automated intelligent system that classifies sea ice and that is now being used by the U.S. National Ice Center (NIC) for daily operations related to the NIC’s task of mapping the ice covered oceans. In this paper we describe the process of taking a research project and transitioning it to an operational environment. We discuss the theoretical methodologies implemented in ARKTOS, and how ARKTOS was developed, tested, and finally moved to operations.


A Dual Encryption Protocol For Scalable Secure Multicasting, Lakshminath R. Dondeti, Sarit Mukherjee, Ashok K. Samal Jan 1999

A Dual Encryption Protocol For Scalable Secure Multicasting, Lakshminath R. Dondeti, Sarit Mukherjee, Ashok K. Samal

CSE Conference and Workshop Papers

In this paper we propose a dual encryption protocol for scalable secure multicasting. Multicasting is a scalable solution for group communication. It howevel; poses several unique security problems. We use hierarchical subgrouping to achieve scalability. Third party hosts or members of the multicast group are designated as subgroup managers. They are responsible for secret key distribution and group membership management at the subgroup level. Unlike existing secure multicast protocols, our protocol need not trust the subgroup managers with the distribution of data encryption keys. The dual encryption protocol proposed in this paper distributes encrypted data encryption keys via subgroup managers. …


Routing Algorithms For All-Optical Networks With Power Considerations: The Unicast Case, Maher Ali, Byrav Ramamurthy, Jitender S. Deogun Jan 1999

Routing Algorithms For All-Optical Networks With Power Considerations: The Unicast Case, Maher Ali, Byrav Ramamurthy, Jitender S. Deogun

CSE Conference and Workshop Papers

In this paper, we investigate the problem of routing connections in all-optical networks while allowing for degradation of routed signals by different optical components. To overcome the complexity of the problem, we divide it into two parts. First, we solve the pure RWA problem using fixed routes for every connection. Second, power assignment is accomplished by either using the smallest-gain first (SGF) heuristic or using a genetic algorithm. Numerical examples on a wide variety of networks show that (a) the number of connections established without considering the signal attenuation was most of the time greater than that achievable considering attenuation …


Transparent Vs. Opaque Vs. Translucent Wavelength-Routed Optical Networks, Byrav Ramamurthy, Helena Feng, Debasish Datta, Jonathan P. Heritage, Biswanath Mukherjee Jan 1999

Transparent Vs. Opaque Vs. Translucent Wavelength-Routed Optical Networks, Byrav Ramamurthy, Helena Feng, Debasish Datta, Jonathan P. Heritage, Biswanath Mukherjee

CSE Conference and Workshop Papers

A wavelength-routed optical network consists of multi-wavelength crossconnect switches (XCSs) which are interconnected by optical fibers. Some (or all) crossconnects, referred to as nodes in this paper, are also attached to access stations where data from several end-users could be multiplexed onto a single wavelength division multiplexed (WDM) channel. An access station provides optical-to-electronic (O/E) conversion and wice wersa to interface the optical network with conventional electronic equipment. The access station, at an intermediate node, may also be used (as in this study) for signal regenerution on a lightpath. A new call is admitted into the network if a lightpath …


A Synthesis For Testability Scheme For Finite State Machines Using Clock Control, Kent L. Einspahr, Shashank K. Mehta, Sharad C. Seth Jan 1999

A Synthesis For Testability Scheme For Finite State Machines Using Clock Control, Kent L. Einspahr, Shashank K. Mehta, Sharad C. Seth

School of Computing: Faculty Publications

A new method is proposed for improving the testability of a finite state machine (FSM) during its synthesis. The method exploits clock control to enhance the controllability and observability of machine states. With clock control it is possible to add new state transitions during testing. Therefore, it is easier to navigate between states in the resulting test machine. Unlike prior work, where clock control is added to the circuit as a postdesign step, here, clock control is considered in conjunction with a symbolic scheme for encoding the states of the FSM. The encoding is shown to result in significant reductions …