@conference {
	title = {Parameter Identification of Large Spacecraft Systems Based on Frequency Characteristics},
	author = {Augenstein, Donald R., Baras, John S., Fisher, Shalom M.},
	year = {1992},
	month = {12/1992},
	abstract = {In this paper we describe parameter identification for an in-orbit satellite. Actual experimental results are described for the Low Atmospheric Control Experiment (LACE) spacecraft. This is a low earth orbit satellite that was launched into a circular orbit. Its structure consists of a central rigid body or bus with three deployable booms. We accomplished the identification of the structural modes and damping factors of the spacecraft in orbit utilizing the frequency characteristics of the Hankel operator. Frequency domain error bounds and time domain error bounds were considered. The experiment utilized ground based laser illumination and identified three of the lowest vibration modes. The accuracy of the methods was extremely good.},
	address = {Tucson, Arizona},
	booktitle = { The 31st IEEE Conference on Decision and Control},
	pages = {pp. 1696-1701},
	organization = {Westin La Paloma}
}
@conference {
	title = {Optimal Filtering of Digital Binary Images Corrupted by Union/Intersection Noise},
	author = {Sidiropoulos, N D., Baras, John S., Berenstein, Carlos A.},
	year = {1992},
	month = {12/1992},
	abstract = {We model digital binary image data as realizations of a uniformly bounded discrete random set (or discrete random set, for short), a mathematical object which can be directly defined on a finite lattice. We consider the problem of estimating realizations of discrete random sets distorted by a degradation process which can be described by a union/intersection noise model. We start by providing some theoretical justification of the popularity of certain Morphological filters, namely Morphological openings, closings, unions of openings, and intersections of closings. In particular, we prove that if the signal is {\textquotedblleft}smooth{\textquotedblright}, then these filters are optimal (in the sense of providing the MAP estimate of the signal) under reasonable worst-case statistical scenarios. Then we consider a class of filters which arises quite naturally from the set-theoretic analysis of optimal filters. We call this the class of mask filters. We consider both fixed and adaptive mask filters~and derive explicit formulas for the optimal mask filter under quite general assumptions on the signal and the degradation process.},
	address = {Tucson, Arizona},
	booktitle = { The 31st IEEE Conference on Decision and Control},
	pages = {pp. 3287-3292},
	organization = {Westin La Paloma}
}
@conference {
	title = {An Adaptive Quasi-Linear Representation-A Generalization of the Multiscale Edge Representation},
	author = {Berman, Zeev., Baras, John S.},
	year = {1992},
	month = {12/1992},
	abstract = {The analysis of the discrete multiscale edge representation is considered. A general signal description, called an inherently bounded Adaptive Quasi Linear Representation (AQLR), motivated by two important examples: the wavelet maxima representation and the wavelet zero crossings representation is introduced. This paper addresses the questions of uniqueness, stability, and reconstruction. It is shown, that the dyadic wavelet maxima (zero-crossings) representation is, in general, nonunique. Nevertheless, these representations are always stable. A reconstruction algorithm, based on the minimization of an appropriate cost function, is proposed. The convergence of the algorithm is guaranteed for all inherently bounded AQLR. In the case, of the wavelet transform, this method yields an efficient, parallel algorithm, especially promising in an analog-hardware implementation},
	address = {Tucson, Arizona},
	booktitle = { The 31st IEEE Conference on Decision and Control},
	pages = {pp. 3281-3286},
	organization = {Westin La Paloma}
}
@conference {
	title = {Optimal Routing in Mixed Media Networks with Integrated Voice and Data Traffic},
	author = {Chen, Shihwei., Baras, John S.},
	year = {1992},
	month = {12/1992},
	abstract = {In this paper, we consider a large mixed-media network which consists of a low-delay terrestrial sub-network and a high-bandwidth satellite sub-network. Both voice and data traffic are transmitted and routed through the same network. We show how to route both traffic via ground and/or satellite links by means of static, deterministic procedures. Two common voice/data integrated protocols such as fixed boundary and movable boundary schemes for the satellite channel are investigated, and the performance of both schemes is evaluated. The optimal splitting ratios for voice and data at the SIMPs (Satellite Interface Message Processors) are found using a powerful numerical optimization package (FSQP).},
	address = {Orlando, Florida},
	booktitle = {The Globecom 92},
	pages = {pp. 335-339}
}
@conference {
	title = {Optimal Morphological Filters for Discrete Random Sets under a  Union or Intersection Noise},
	author = {Sidiropoulos, N D., Baras, John S., Berenstein, Carlos A.},
	year = {1992},
	month = {11/1992},
	abstract = {We consider the problem of optimal binary image restoration under a union or intersection noise model. Union noise is well suited to model random clutter (obscuration), whereas intersection noise is a good model for random sampling. Our approach is random set-theoretic, i.e. digital images are viewed as realizations of a uniformly bounded discrete random set. First we provide statistical proofs of some "folk theorems{\textquotedblright} of Morphological filtering. In particular, we prove that, under some reasonable worst-case statistical scenarios, Morphological openings, closings, unions of openings, and intersections of closings, can be viewed as MAP estimators of the signal based on the noisy observation. Then we propose a "generic{\textquotedblright} procedure for the design of optimal Morphological filters for independent union or intersection noise.},
	address = {Boston, Massachusetts},
	booktitle = {The SPIE Conference on Visual Communication \& Image Processing},
	pages = {pp. 402-413}
}
@conference {
	title = {Distributed Control of a Timoshenko Beam},
	author = {Zhuang, Yan., Baras, John S.},
	year = {1992},
	month = {11/1992},
	abstract = {We consider a flexible beam clamped to a rigid base on one end with the other end free. In order to stabilize the beam vibration, we introduce active damping into the beam with feedback control using distributed actuators and sensors. We apply Tim Oshenko beam theory to model the substructure. Unlike the familiar Euler-Bernoulli beam model, the shear effect and the rotational inertia are included in the modeling of elastic deformation to obtain a more precise beam model. The piezoelectric~theory is briefly reviewed. The piezoelectric ceramic material (PZT) is used to build the distributed actuator. The distributed sensor is made of piezoelectric polymer polyvinylidene fluoride (PVDF). The sensor and actuator are layers which are attached directly to both sides of the beam. Based on the constitutive properties and layer geometry, the models for sensor and actuator are developed. We then embed the static actuator and sensor models into the beam substructure to form the model of the composite beam. We design the feedback controller by Lyapunov direct methods based on the energy functional of the system. It is proved that the derived controller can extract energy from the system and increase system damping. The resulting closed loop system is asymptotically stable. Since this method does not depend on model truncation, we further analyze the combined effect of the distributed controller on the relevant vibration modes. It is possible to suppress the selected modes by choosing the appropriate actuator layout. It is also shown that by properly installing the sensor and determining the sensor shape function,~we can further extract and manipulate the sensor signal for our control need.

~

~},
	address = {San Diego, CA},
	booktitle = {The Third International Conference on Adaptive Structures},
	pages = {pp. 216-227}
}
@conference {
	title = {Stochastic Morphology and Nonlinear Filtering of Digital Images},
	author = {Baras, John S.},
	year = {1992},
	month = {11/1992},
	address = {Quebec, Canada},
	booktitle = {Workshop on Stochastic Control},
	organization = {Centre de Recherches Mathematiques, Universite de Montreal}
}
@conference {
	title = {Robust Free-Text Speaker Identification Over Long Distance Telephone Channels},
	author = {Kao, Yu-Hung., Rajasekaran, P K. , Baras, John S.},
	year = {1992},
	month = {10/1992},
	abstract = {Usable free-text speaker identification and voice verification systems must exhibit robustness under varying Operational conditions. We study the degree of robustness provided by various signal processing techniques [1] [2] [3] by experimenting on a widely used long distance telephone data base [4] [5]~[6]. This data base consists of data recorded at two different sites, with data from one site much poorer in quality than the other; further, the recording equipment had been inadvertently changed for the later half of the sessions resulting in a significantly changed environment. Our study identifies the combination of techniques that provide consistent and significant improvements, our results surpass other published results [4] [5]~[6] on the same task. Specifically, in the task of identifying 16 speakers, with training data from the recording prior to equipment change and testing on data from a set after the change (the most challenging condition), we obtain a correct identification rate of 87.5\% with an average rank of 1.12; [4]~obtains the hitherto best result of 75\% correct identification with an average rank of 1.56; without any robustness processing, the rate was only 12\%. Detailed results on exhaustive experimentation are presented along with appropriate discussions.},
	address = {Piscataway, New Jersey},
	booktitle = { IEEE Workshop on Interactive Voice Technology for Telecommunications Applications},
	pages = {pp. 1-5}
}
@conference {
	title = {Hybrid (Satellite and Terrestrial) Communication Networks:  Object Oriented Generic Tools for Simulation and Management},
	author = {Baras, John S., Charuhas, Thomas.},
	year = {1992},
	month = {10/1992},
	abstract = {We describe a generic object oriented software environment for the simulation and management of hybrid communication networks (satellite and terrestrial) under development at the University of Maryland, as part of the NASA CCDS program. We refer to this environment as a "systems engineering workstation for hybrid networks". It will have the capability to model such networks in a totally object oriented environment and link to network performance evaluation modules. Satellites are treated both as electronic/mechanical systems and as communication nodes. Great flexibility is allowed for defining the various components of the satellite, including its type (i.e. LEO or GEO), on board processing capabilities, bandwidth, multiple access scheme, linkage to terrestrial networks. The satellite link is also treated as an object allowing great flexibility in modeling weather effects, multipath interference and coverage. We show the system{\textquoteright}s flexibility in studying combined adaptive routing and access for voice-data large hybrid networks.},
	address = {San Diego, California},
	booktitle = {1992 IEEE MILCOM Conference},
	pages = {pp. 0553-0559}
}
@conference {
	title = {The Parametric Wavelet Maxima Representation},
	author = {Berman, Zeev., Baras, John S., Berenstein, Carlos A.},
	year = {1992},
	month = {10/1992},
	abstract = {A general signal description, called an inherently bounded Adaptive Quasi Linear Representation (AQLR), motivated by two important examples, namely, the wavelet maxima representation, and the wavelet zero-crossings representation, is introduced. This paper presents a new reconstruction scheme based on the minimization of an appropriate cost function. The convergence of two described algorithms is guaranteed for all inherently bounded AQLR. As a consequence, we describe possible modifications in the basic multiscale maxima representations.},
	address = {Victoria, British Columbia, Canada},
	booktitle = {IEEE-SP International Symposium on Time-Frequency and Time-Scale Analysis},
	pages = {pp. 59-62}
}
@conference {
	title = {Evaluation of Producibility and Manufacturability of High Power Surveillance T/R Modules},
	author = {McMahon, M., R. Prasannappa, Baras, John S., Zhang, G., Kebede, Abraham., Mendicino, P.},
	year = {1992},
	month = {09/1992},
	abstract = {This paper describes techniques and an implementation for managing costs and quality of electronics products during design. Emphasis is given to the development of an economic model to estimate the production costs at the assembly level. The unique feature of this system is to bring the experience of a manufacturing engineer, quality engineer, and cost controller into the hands of a designer. Such an early integration of manufacturing knowledge creates a concurrent engineering environment which~improves product quality and reduces cost through careful monitoring of the design phase.},
	address = {Baltimore, Maryland},
	booktitle = {13th International Electronics Manufacturing Technology Symposium},
	pages = {pp. 266-271},
	organization = {Inner Harbor}
}
@conference {
	title = {Uniqueness and Stability of Discrete Zero-Crossings and Maxima Wavelet Representations},
	author = {Berman, Zeev., Baras, John S.},
	year = {1992},
	month = {08/1992},
	abstract = {A general signal description, called an inherently bounded Adaptive Quasi Linear Representation (AQLR), motivated by two important examples, namely the wavelet maxima representation, and the wavelet zero-crossings representation, is introduced. It is shown, that the dyadic wavelet maxima~(zero-crossings) representation is, in general, nonunique. Using the idea of the inherently bounded AQLR, a global BIBO stability is shown. For a special case, where perturbations are limited to the continuous part of the representation, a Lipschitz condition is satisfied.},
	address = {Brussels, Belgium},
	booktitle = {6th European Signal Processing Conference (EUSIPCO)},
	pages = {pp. 913-916}
}
@conference {
	title = {Discrete Random Sets: An Inverse Problem, Plus Tools for the Statistical Inference of the Discrete Boolean Model},
	author = {Sidiropoulos, N D., Baras, John S., Berenstein, Carlos A.},
	year = {1992},
	month = {07/1992},
	abstract = {We consider digital binary images as a realization~of a bounded discrete random set, a mathematical object which can be defined directly on a finite lattice. In this setting, we show that it is possible to move between two equivalent probabilistic model specifications. We formulate a restricted version of the discrete-case analog of a Boolean random set model, obtain it{\textquoteright}~probability mass function. and employ some methods of Morphological image analysis to derive tools for its statistical inference.},
	address = {San Diego, California},
	booktitle = {SPIE Conference on Image Algebra and Morphological Image Processing III},
	pages = {pp. 32-43}
}
@conference {
	title = {Optimization, Intelligent Control and Complexity},
	author = {Baras, John S.},
	year = {1992},
	month = {06/1992},
	address = {London, UK},
	booktitle = {Systems and Control Themes for the Nineties, A Conference in honor of Professor David Mayne},
	organization = {Imperial College}
}
@conference {
	title = { Parameter Identification of Large Spacecraft Systems Based on Frequency Characteristics},
	author = {Augenstein, Donald R., Baras, John S., Fisher, Shalom M.},
	year = {1992},
	month = {06/1992},
	abstract = {In this paper we describe parameter identification for an in-orbit satellite. Actual experimental results are described for the Low Atmospheric Control Experiment (LACE) spacecraft. This is a low earth orbit satellite that was launched into a circular orbit. Its structure consists of a central rigid body or bus with three deployable booms. The first boom is the gravity gradient boom while the second is the retro-reflector boom. We accomplished the identification of the structural modes and damping factors of the spacecraft in orbit. A systems approach was used to analyze the experiment and present identification techniques utilizing the frequency characteristics of the Hankel operator. Frequency domain error bounds and time domain error bounds were considered.

The experiment was performed on a satellite in conjunction with the Naval Research Laboratory. The experiment utilized ground based laser illumination with Doppler shifted returns and identified three of the lowest vibration modes. The accuracy of the methods was extremely good.},
	address = {Sophia-Antipolis, France},
	booktitle = {The 10th International Conference on Analysis and Optimization of Systems},
	pages = {pp. 624-635}
}
@conference {
	title = {Active Vibration Damping Using Smart Material},
	author = {Baras, John S., Zhuang, Yan.},
	year = {1992},
	month = {06/1992},
	abstract = {We consider the Modeling and active damping of an elastic beam using distributed actuators and sensors. The piezoelectric ceramic material (P7T) is used to build the actuator. The sensor is made of the piezoelectric polymer polyvinylidene fluoride (PVDF). These materials are glued on both side of the beam. For the simple clamped beam, the closed loop controller has been shown to be able to extract energy from the beam. The shape of the actuator and its influence on the closed loop system performance are discussed. It is shown that it is possible to suppress the selected mode by choosing the appropriate actuator layout. It is also shown that by properly installing the sensor and determine the sensor shape we can further extract and manipulate the sensor signal for our control need.},
	address = {Williamsburg, Virginia},
	booktitle = {Workshop on Distributed Parameter Modeling and Control of Flexible Aerospace Systems},
	pages = {pp. 1-14}
}
@conference {
	title = {An Analysis of Discrete Zero-Crossings and Maxima Wavelet Representations},
	author = {Zeev Berman, Baras, John S.},
	year = {1992},
	month = {06/1992},
	address = {Toulouse, France}
}
@conference {
	title = {Free-Text Speaker Identification Over Long Distance Telephone Channel Using Hypothesized Phonetic Segmentation},
	author = {Kao, Yu-Hung., Rajasekaran, P K. },
	year = {1992},
	month = {03/1992},
	abstract = {Experimental investigation of free-text speaker identification method based on long-term statistics is conducted on a widely-used long distance telephone data base (l). On a 26-speaker subset, an average correct identification of 93.3\% is obtained; on the complete 51speaker set, 67.6\% correct identification is obtained. Speaker verification experiments on the data base provided receiver operating characteristics (ROC) comparable to or better than the ones available in open literature.},
	address = {San Francisco, CA},
	booktitle = {1992 International Conference on Acoustics, Speech, and Signal Processing (ICAASP)},
	pages = {pp. 177-180}
}
@conference {
	title = {A Study on Discrete Multiscale Edge Representations},
	author = {Berman, Zeev., Baras, John S.},
	year = {1992},
	month = {03/1992},
	abstract = {The analysis of a discrete multiscale edge representation is considered. A general signal description, called an inherently bounded Adaptive Quasi Linear Representation (AQLR), motivated by two important examples, namely, the wavelet maxima representation, and the wavelet zero-crossings representation, is introduced. This paper addresses the questions of uniqueness, stability, and reconstruction. It is shown, that the dyadic wavelet maxima (zero-crossings) representation is, in general, non unique. Nevertheless, these representations are always stable. Using the idea of the inherently bounded AQLR, two stability results are proven. For a general perturbation, a global BIBO stability is shown. For a special case, where perturbations are limited to the continuous part of the representation, a Lipschitz condition is satisfied. A reconstruction algorithm, based on the minimization of an appropriate cost function, is proposed.},
	address = {Princeton, New Jersey},
	booktitle = {Twenty-Sixth Annual Conference on Information Sciences and Systems},
	pages = {pp. 896-901},
	organization = {Princeton University}
}
@conference {
	title = {Optimal Mask Filtering of Discrete Random Sets under a Union/Intersection Noise Model},
	author = {Sidiropoulos, N D., Baras, John S., Berenstein, Carlos A.},
	year = {1992},
	month = {03/1992},
	abstract = {We consider the problem of estimating realizations of highly nonstationary Discrete Random Sets, distorted by a degradation process which can be described by a union/intersection model. We start by presenting some important structural results concerning the probabilistic description of Discrete Random Sets defined on a finite lattice. Then we propose a family of filters which can be viewed as lattice operators, and, for each degradation model, derive the optimal filter by means of minimizing a suitable fidelity criterion.},
	address = {Princeton, New Jersey},
	booktitle = {Twenty-Sixth Annual Conference on Information Sciences and Systems},
	pages = {pp. 313-318},
	organization = {Princeton University}
}
@conference {
	title = {Model-Based ATR:  Algorithms Based on Reduced Target Models, Learning and Probing},
	author = {Baras, John S., MacEnany, David C.},
	year = {1992},
	month = {03/1992},
	abstract = {Two new model based ATR algorithms are presented. The algorithms employ economic target models, recent mathematical developments in the extraction and reduction of target silhouettes from noisy images, and on-line probing for clutter reduction and target classification. The target models used employ a small, carefully selected set of characteristic viewpoints and local features. The design of the algorithms are described and their performance evaluated using synthetic FLIR data. The two algorithms are: the Probing Algorithm and the 4-Way Distance Algorithm. Both algorithms have an early phase which is primarily statistical, and a late phase which is primarily geometric, although the two phases are tightly coupled, with frequent revisitation of the image data used to increase decision confidence. In the Probing Algorithm novel on-line probing is performed using stored target geometric models to efficiently implement a generalized maximum likelihood principle. The Probing Algorithm self-adapts to find the most appropriate target location, range and viewpoint geometry and then performs decision-making based on selected maximum likelihood estimates and on-line computed, optimal probing sets. The 4-Way Distance Algorithm performs decision making based on a classification tree logic utilizing matching scores computed on four components of the target silhouette.},
	address = {Ft. Belvoir, Virginia},
	booktitle = {Second ATR Systems and Technology Conference},
	pages = {pp. 277-300}
}
@conference {
	title = {Scale-Space Polygonalization of Target Silhouettes and Applications to Model-Based ATR},
	author = {MacEnany, David C., Baras, John S.},
	year = {1992},
	month = {03/1992},
	abstract = {Economic descriptions of shapes and objects are essential for model based ATR. In addition to object silhouettes, geometric features such as corners and simplified representations such as polygonal approximations can be used to reduce shape description complexity. Here we analyze the polygonal approximation of object silhouette boundaries. Robust polygonalization for ATR requires the construction of polygonal approximations in various scales; namely polygons preserving features of the boundary with varying resolution. In this paper we introduce the notion of scalespace polygonalization. Scale-space polygonalization allows for the generation of polygonal approximations across a range of resolutions and achieve vertex localization which is uniform in scale. The notion of scale or resolution for a polygon involves the distances between its vertices and the magnitude of its vertex angles. Fine scale implies high resolution of the details of boundary contours while coarse scale implies only gross details of boundary contours with a consequent reduction of both computational and descriptive complexity. The polygonalization methods and algorithms presented here are novel in that we control the reduction of the contour complexity by adjusting resolution parameters which have a natural interpretation and achieve vertex localization which is uniform in scale and persistent in scale. These polygonalized boundaries can be used to generate a target fingerprint across a range of scales. Scale-space polygons are important for ATR because they provide a way to reduce the complexity of digitized planar curves consisting of polygons having hundreds of sides to polygons of about a dozen sides, while still capturing the essential features of the model silhouette. This is desirable because shorter polygonal descriptions yield faster correlations and matchings and reduce the overall computational complexity of the ATR problem. We show how scale-space polygonalization can be used to obtain efficient representations of targets, and fast matching algorithms. We also show how scale-space polygons can be used to obtain stable edges from noisy images. We demonstrate these results on examples involving synthetic FLIR data and CAD target models.},
	address = {Ft. Belvoir, Virginia},
	booktitle = {Second ATR Systems and Technology Conference},
	pages = {pp. 223-247}
}
