Publications

@inproceedings{rickel_intelligent_2001,

title = {Intelligent Virtual Agents for Education and Training: Opportunities and Challenges},

author = {Jeff Rickel},

url = {http://ict.usc.edu/pubs/Intelligent%20Virtual%20Agents%20for%20Education%20and%20Training-%20Opportunities%20and%20Challenges.pdf},

year  = {2001},

date = {2001-09-01},

booktitle = {Intelligent Virtual Agents: The 3rd International Workshop},

address = {Madrid, Spain},

abstract = {Interactive virtual worlds provide a powerful medium for ex- periential learning. Intelligent virtual agents can cohabit virtual worlds with people and facilitate such learning as guides, mentors, and team- mates. This paper reviews the main pedagogical advantages of animated agents in virtual worlds, discusses two key research challenges, and out- lines an ambitious new project addressing those challenges.},

keywords = {},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{bharitkar_new_2001,

title = {New Factors in Room Equalization Using a Fuzzy Logic Approach},

author = {Sunil Bharitkar and Chris Kyriakakis},

url = {http://ict.usc.edu/pubs/New%20Factors%20in%20Room%20Equalization%20Using%20a%20Fuzzy%20Logic%20Approach.pdf},

year  = {2001},

date = {2001-09-01},

booktitle = {Proceedings of the Audio Engineering Society Convention},

address = {New York, NY},

abstract = {Room acoustical modes, particularly in small rooms, cause a significant variation in the room responses measured at di!erent locations. Responses measured only a few cm apart can vary by up to 15-20 dB at certain frequencies. This makes it diffcult to equalize an audio system for multiple simultaneous listeners. Previous methods have utilized multiple microphones and spatial averaging with equal weighting. In this paper we present a different multiple point equalization method. We first determine representative prototypical room responses derived from several room responses that share similar characteristics, using the fuzzy unsupervised learning method. These prototypical responses can then be combined to form a general point response. When we use the inverse of the general point response as an equalizing filter, our results show a significant improvement in equalization performance over the spatial averaging methods. This simultaneous equalization is achieved by suppressing the peaks in the room magnitude spectrums. Applications of this method thus include equalization and multiple point sound control at home and in automobiles.},

keywords = {},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{marsella_effect_2001,

title = {The Effect of Affect: Modeling the Impact of Emotional State on the Behavior of Interactive Virtual Humans},

author = {Stacy C. Marsella and Jonathan Gratch and Jeff Rickel},

url = {http://ict.usc.edu/pubs/The%20Effect%20of%20Affect-%20Modeling%20the%20Impact%20of%20Emotional%20State%20on%20the%20Behavior%20of%20Interactive%20Virtual%20Humans.pdf},

year  = {2001},

date = {2001-06-01},

booktitle = {Workshop on Representing, Annotating, and Evaluating Non-Verbal and Verbal Communicative Acts to Achieve Contextual Embodied Agents},

address = {Montreal, Canada},

abstract = {A person's behavior provides significant information about their emotional state, attitudes, and attention. Our goal is to create virtual humans that convey such information to people while interacting with them in virtual worlds. The virtual humans must respond dynamically to the events surrounding them, which are fundamentally influenced by users' actions, while providing an illusion of human-like behavior. A user must be able to interpret the dynamic cognitive and emotional state of the virtual humans using the same nonverbal cues that people use to understand one another. Towards these goals, we are integrating and extending components from three prior systems: a virtual human architecture with a range of cognitive and motor capabilities, a model of emotional appraisal, and a model of the impact of emotional state on physical behavior. We describe the key research issues, our approach, and an initial implementation in an Army peacekeeping scenario.},

keywords = {Social Simulation, Virtual Humans},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{douglas_adaptive_2001,

title = {Adaptive Narrative: How Autonomous Agents, Hollywood, and Multiprocessing Operating Systems Can Live Happily Ever After},

author = {Jay Douglas and Jonathan Gratch},

url = {http://ict.usc.edu/pubs/Adaptive%20Narrative-%20How%20Autonomous%20Agents,%20Hollywood,%20and%20Multiprocessing%20Operating%20Systems%20Can%20Live%20Happily%20Ever%20After.pdf},

year  = {2001},

date = {2001-06-01},

booktitle = {Proceedings of the 5th International Conference on Autonomous Agents},

address = {Montreal, Canada},

abstract = {Creating dramatic narratives for real-time virtual reality environments is complicated by the lack of temporal distance between the occurrence of an event and its telling in the narrative. This paper describes the application of a multiprocessing operating system architecture to the creation of adaptive narratives, narratives that use autonomous actors or agents to create real-time dramatic experiences for human interactors. We also introduce the notion of dramatic acts and dramatic functions and indicate their use in constructing this real-time drama.},

keywords = {Virtual Humans},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{cohen_real-time_2001,

title = {Real-Time High-Dynamic Range Texture Mapping},

author = {Jonathan Cohen and Chris Tchou and Tim Hawkins and Paul Debevec},

url = {http://ict.usc.edu/pubs/Real-Time%20High-Dynamic%20Range%20Texture%20Mapping.pdf},

year  = {2001},

date = {2001-06-01},

booktitle = {Eurographics Rendering Workshop},

abstract = {This paper presents a technique for representing and displaying high dynamic-range texture maps (HDRTMs) using current graphics hardware. Dynamic range in real-world environments often far exceeds the range representable in 8-bit per-channel texture maps. The increased realism afforded by a high-dynamic range representation provides improved fidelity and expressiveness for interactive visualization of image-based models. Our technique allows for real-time rendering of scenes with arbitrary dynamic range, limited only by available texture memory. In our technique, high-dynamic range textures are decomposed into sets of 8- bit textures. These 8-bit textures are dynamically reassembled by the graphics hardware's programmable multitexturing system or using multipass techniques and framebuffer image processing. These operations allow the exposure level of the texture to be adjusted continuously and arbitrarily at the time of rendering, correctly accounting for the gamma curve and dynamic range restrictions of the display device. Further, for any given exposure only two 8-bit textures must be resident in texture memory simultaneously. We present implementation details of this technique on various 3D graphics hardware architectures. We demonstrate several applications, including high-dynamic range panoramic viewing with simulated auto-exposure, real-time radiance environment mapping, and simulated Fresnel reflection.},

keywords = {Graphics},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{swartout_toward_2001,

title = {Toward the Holodeck: Integrating Graphics, Sound, Character and Story},

author = {William Swartout and Randall W. Hill and Jonathan Gratch and W. Lewis Johnson and Chris Kyriakakis and Catherine Labore and Richard Lindheim and Stacy C. Marsella and D. Miraglia and Bridget Moore and Jacquelyn Morie and Jeff Rickel and Marcus Thiebaux and L. Tuch and Richard Whitney and Jay Douglas},

url = {http://ict.usc.edu/pubs/Toward%20the%20Holodeck-%20Integrating%20Graphics,%20Sound,%20Character%20and%20Story.pdf},

year  = {2001},

date = {2001-06-01},

booktitle = {Proceedings of the 5th International Conference on Autonomous Agents},

address = {Montreal, Canada},

abstract = {We describe an initial prototype of a holodeck-like environment that we have created for the Mission Rehearsal Exercise Project. The goal of the project is to create an experience learning system where the participants are immersed in an environment where they can encounter the sights, sounds, and circumstances of realworld scenarios. Virtual humans act as characters and coaches in an interactive story with pedagogical goals.},

keywords = {Social Simulation, Virtual Humans, Virtual Worlds},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{gratch_modeling_2001,

title = {Modeling Emotions in the Mission Rehearsal Exercise},

author = {Jonathan Gratch and Stacy C. Marsella},

url = {http://ict.usc.edu/pubs/Modeling%20Emotions%20in%20the%20Mission%20Rehearsal%20Exercise.pdf},

year  = {2001},

date = {2001-05-01},

booktitle = {Proceedings of the 10th Conference on Computer Generated Forces and Behavioral Representation},

pages = {457–466},

address = {Orlando, FL},

abstract = {This paper discusses our attempts to model realistic human behavior in the context of the Mission Rehearsal Exercise system (MRE), a high-end virtual training environment designed to support dismounted infantry training between a human participant and elements of his command. The system combines immersive graphics, sound, and interactive characters controlled by artificial intelligence programs. Our goal in this paper is to show how some of the daunting subtlety in human behavior can be modeled by intelligent agents and in particular to focus on the role of modeling typical human emotional responses to environmental stimuli.},

keywords = {Social Simulation, Virtual Humans},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{ligorio_interlocution_2001,

title = {Interlocution Scenarios for Problem Solving in an Educational MUD Environment},

author = {M. Beatrice Ligorio and Giuseppe Mininni and David Traum},

url = {http://ict.usc.edu/pubs/INTERLOCUTION%20SCENARIOS%20FOR%20PROBLEM%20SOLVING%20IN%20AN%20EDUCATIONAL%20MUD%20ENVIRONMENT.pdf},

year  = {2001},

date = {2001-03-01},

booktitle = {1st European Conference on Computer-Supported Collaborative Learning},

abstract = {This paper presents an analysis of computer mediated collaboration on a problem-solving task in a virtual world. The theoretical framework of this research combines research in Computer Mediated Communication with a social psychology theory of conflict. An experiment was conducted involving universitybstudents performing a problem solving task with a peer in an Educational MUD. Each performance was guided by a predefined script, designed based on the 'common speech' concepts. Al the performances were analyzed in terms of identity perception, conflict perception and cooperation. By looking at the relationship among the CMC environment features, the social influence activated on this environment, the conflict elaboration, and the problem solving strategies, a distinctive 'interlocution scenario' emerged. The results are discussed using contributions from the two theoretical approaches embraced.},

keywords = {Virtual Humans},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{gratch_tears_2001,

title = {Tears and Fears: Modeling emotions and emotional behaviors in synthetic agents},

author = {Jonathan Gratch and Stacy C. Marsella},

url = {http://ict.usc.edu/pubs/Tears%20and%20Fears-%20Modeling%20emotions%20and%20emotional%20behaviors%20in%20synthetic%20agents.pdf},

year  = {2001},

date = {2001-01-01},

booktitle = {Proceedings of the 5th International Conference on Autonomous Agents},

pages = {278–285},

address = {Montreal, Canada},

abstract = {Emotions play a critical role in creating engaging and believable characters to populate virtual worlds. Our goal is to create general computational models to support characters that act in virtual environments, make decisions, but whose behavior also suggests an underlying emotional current. In service of this goal, we integrate two complementary approaches to emotional modeling into a single unified system. Gratch's Émile system focuses on the problem of emotional appraisal: how emotions arise from an evaluation of how environmental events relate to an agent's plans and goals. Marsella et al. 's IPD system focuses more on the impact of emotions on behavior, including the impact on the physical expressions of emotional state through suitable choice of gestures and body language. This integrated model is layered atop Steve, a pedagogical agent architecture, and exercised within the context of the Mission Rehearsal Exercise, a prototype system designed to teach decision- making skills in highly evocative situations.},

keywords = {Social Simulation, Virtual Humans},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{hawkins_photometric_2001,

title = {A Photometric Approach to Digitizing Cultural Artifacts},

author = {Tim Hawkins and Jonathan Cohen and Paul Debevec},

url = {http://ict.usc.edu/pubs/A%20Photometric%20Approach%20to%20Digitizing%20Cultural%20Artifacts.pdf},

year  = {2001},

date = {2001-01-01},

booktitle = {Proceedings of 2nd International Symposium on Virtual Reality, Archaeology and Cultural Heritage},

address = {Glyfada, Greece},

abstract = {In this paper we present a photometry-based approach to the digital documentation of cultural artifacts. Rather than representing an artifact as a geometric model with spatially varying reflectance properties, we instead propose directly representing the artifact in terms of its reflectance field - the manner in which it transforms light into images. The principal device employed in our technique is a computer-controlled lighting apparatus which quickly illuminates an artifact from an exhaustive set of incident illumination directions and a set of digital video cameras which record the artifact's appearance under these forms of illumination. From this database of recorded images, we compute linear combinations of the captured images to synthetically illuminate the object under arbitrary forms of complex incident illumination, correctly capturing the effects of specular reflection, subsurface scattering, self-shadowing, mutual illumination, and complex BRDF's often present in cultural artifacts. We also describe a computer application that allows users to realistically and interactively relight digitized artifacts.},

keywords = {Graphics},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{lee_recognition_2001,

title = {Recognition of Negative Emotions from the Speech Signal},

author = {C. M. Lee and Shrikanth Narayanan and R. Pieraccin},

url = {http://ict.usc.edu/pubs/Recognition%20of%20Negative%20Emotions%20from%20the%20Speech%20Signal.pdf},

year  = {2001},

date = {2001-01-01},

booktitle = {Proceedings of Automatic Speech Recognition and Understanding Workshop (ASRU 2001)},

abstract = {This paper reports on methods for automatic classification of spoken utterances based on the emotional state of the speaker. The data set used for the analysis comes from a corpus of human- machine dialogs recorded from a commercial application deployed by SpeechWorks. Linear discriminant classification with Gaussian class-conditional probability distribution and knearest neighborhood methods are used to classify utterances into two basic emotion states, negative and non-negative. The features used by the classifiers are utterance-level statistics of the fundamental frequency and energy of the speech signal. To improve classification performance, two specific feature selection methods are used; namely, promising first selection and forward feature selection. Principal component analysis is used to reduce the dimensionality of the features while maximizing classification accuracy. Improvements obtained by feature selection and PCA are reported in this paper. We reported the results.},

keywords = {},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{hawkins_light_2001,

title = {Light Stage 2.0},

author = {Tim Hawkins and Jonathan Cohen and Chris Tchou and Paul Debevec},

url = {http://ict.usc.edu/pubs/Light%20Stage%202.pdf},

year  = {2001},

date = {2001-01-01},

booktitle = {SIGGRAPH Technical Sketches},

pages = {217},

keywords = {Graphics},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{olsen_implicit_2001,

title = {Implicit Cues for Explicit Generation: Using Telicity as a Cue for Tense Structure in Chinese to English MT System},

author = {Mari Olsen and David Traum and Carol Van Ess-Dykema and Amy Weinberg},

url = {http://ict.usc.edu/pubs/Implicit%20Cues%20for%20Explicit%20Generation-%20Using%20Telicity%20as%20a%20Cue%20for%20Tense%20Structure%20in%20Chinese%20to%20English%20MT%20System.pdf},

year  = {2001},

date = {2001-01-01},

booktitle = {Machine Translation Summit VIII},

address = {Santiago de Compostela, Spain},

abstract = {In translating from Chinese to English, tense and other temporal information must be inferred from other grammatical and lexical cues. Tense information is crucial to providing accurate and fluent translations into English. Perfective and imperfective grammatical aspect markers can provide cues to temporal structure, but such information is optional in Chinese and is not present in the majority of sentences. We report on a project that assesses the relative contribution of the lexical aspect features of (a)telicity reflected in the Lexical Conceptual Structure of the input text, versus more overt aspectual and adverbial markers of tense, to suggest tense structure in the English translation of a Chinese newspaper corpus. Incorporating this information allows a 20% to 35% boost in the accuracy of tense relization with the best accuracy rate of 92% on a corpus of Chinese articles.},

keywords = {Virtual Humans},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{yang_embedded_2001,

title = {Embedded High-Quality Multichannel Audio Coding},

author = {Dai Yang and Hongmei Ai and Chris Kyriakakis and C. -C. Jay Kuo},

url = {http://ict.usc.edu/pubs/Embedded%20High-Quality%20Multichannel%20Audio%20Coding.pdf},

year  = {2001},

date = {2001-01-01},

booktitle = {Conference on Media Processors, Symposium on Electronic Imaging},

address = {San Jose, CA},

abstract = {An embedded high-quality multi-channel audio coding algorithms is proposed in this research. The Karhunen-Loeve Transform (KLT) is applied to multichannel audio signals in the pre-processing stage to remove inter-channel redundancy. Then, after processing of several audio coding blocks, transformed coefficients are layered quantized and the bit stream is ordered according to their importance. The multichannel audio bit stream generated by the propoesed algorithm has a fully progressive property, which is highly desirable for audio multicast applications in heterogenous networks. Experimental results show that, compared with the MPEG Advanced Audio Coding (AAC) algorithm, the proposed algorithm achieves a better performance with both the objective MNR (Mask-to-Noise-Ratio) measurement and the subjective listening test at several different bit rates.},

keywords = {},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{waese_real_2001,

title = {A Real Time High Dynamic Range Light Probe},

author = {Jamie Waese and Paul Debevec},

url = {http://ict.usc.edu/pubs/A%20Real%20Time%20High%20Dynamic%20Range%20Light%20Probe.pdf},

year  = {2001},

date = {2001-01-01},

booktitle = {SIGGRAPH Technical Sketches},

keywords = {Graphics},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{bharitkar_cluster_2001,

title = {A Cluster Centroid Method for Room Response Equalization at Multiple Locations},

author = {Sunil Bharitkar and Chris Kyriakakis},

url = {http://ict.usc.edu/pubs/A%20CLUSTER%20CENTROID%20METHOD%20FOR%20ROOM%20RESPONSE%20EQUALIZATION%20AT%20MULTIPLE%20LOCATIONS.pdf},

isbn = {0-7803-7126-7},

year  = {2001},

date = {2001-01-01},

booktitle = {IEEE Workshop on the Applications of Signal Processing to Audio and Acoustics},

pages = {55–58},

address = {New Platz, NY},

abstract = {In this paper we address the problem of simultaneous room response equalization for multiple listeners. Traditional approaches to this problem have used a single microphone at the listening position to measure impulse responses from a loudspeaker and then use an inverse filter to correct the frequency response. The problem with that approach is that it only works well for that one point and in most cases is not practical even for one listener with a typical ear spacing of 18 cm. It does not work at all for other listeners in the room, or if the listener changes positions even slightly. We propose a new approach that is based on the Fuzzy c-means clustering technique. We use this method to design equalization filters and demonstrate that we can achieve better equalization performance for several locations in the room simultaneously as compared to single point or simple averaging methods.},

keywords = {},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{srinivasamurthy_use_2001,

title = {Use of Model Transformations for Distributed Speech Recognition},

author = {Naveen Srinivasamurthy and Shrikanth Narayanan and Antonio Ortega},

url = {http://ict.usc.edu/pubs/Use%20of%20Model%20Transformations%20for%20Distributed%20Speech%20Recognition.pdf},

year  = {2001},

date = {2001-01-01},

booktitle = {4th ISCA Tutorial and Research Workshop on Speech Synthesis},

pages = {113–116},

address = {Sophia Antipolis, France},

abstract = {Due to bandwidth limitations, the speech recognizer in distributed speech recognition (DSR) applications has to use encoded speech - either traditional speech encoding or speech encoding optimized for recognition. The penalty incurred in reducing the bitrate is degradation in speech recognition performance. The diversity of the applications using DSR implies that a variety of speech encoders can be used to compress speech. By treating the encoder variability as a mismatch we propose using model transformation to reduce the speech recognition performance degradation. The advantage of using model transformation is that only a single model set needs to be trained at the server, which can be adapted on the fly to the input speech data. We were able to reduce the word error rate by 61.9%, 63.3% and 56.3% for MELP, GSM and MFCC-encoded data, respectively, by using MAP adaptation, which shows the generality of our proposed scheme.},

keywords = {},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{damiano_anticipatory_2001,

title = {Anticipatory planning for decision-theoretic grounding and task advancement in mixed-initiative dialogue systems},

author = {Rossana Damiano and David Traum},

url = {http://ict.usc.edu/pubs/Anticipatory%20planning%20for%20decision-theoretic%20grounding%20and%20task%20advancement%20in%20mixed-initiative%20dialogue%20systems.pdf},

year  = {2001},

date = {2001-01-01},

booktitle = {NAACL 2001 Workshop on Adaptation in Dialogue Systems},

keywords = {Virtual Humans},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{marsella_modeling_2001,

title = {Modeling the Interplay of Emotions and Plans in Multi-Agent Simulations},

author = {Stacy C. Marsella and Jonathan Gratch},

url = {http://ict.usc.edu/pubs/Modeling%20the%20Interplay%20of%20Emotions%20and%20Plans%20in%20Multi-Agent%20Simulations.pdf},

year  = {2001},

date = {2001-01-01},

booktitle = {Proceedings of 23rd Annual Conference of the Cognitive Science Society},

address = {Edinburgh, Scotland},

abstract = {The goal of this research is to create general computational models of the interplay between affect, cognition and behavior. These models are being designed to support characters that act in virtual environments, make decisions, but whose behavior also suggests an underlying emotional current. We attempt to capture both the cognitive and behavioral aspects of emotion, circumscribed to the role emotions play in the performance of concrete physical tasks. We address how emotions arise from an evaluation of the relationship between environmental events and an agent's plans and goals, as well as the impact of emotions on behavior, in particular the impact on the physical expressions of emotional state through suitable choice of gestures and body language. The approach is illustrated within a virtual reality training environment.},

keywords = {Social Simulation, Virtual Humans},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{yang_adaptive_2001,

title = {Adaptive Karhunen-Loeve Transform for Enhanced Multichannel Audio Coding},

author = {Dai Yang and Hongmei Ai and Chris Kyriakakis and C. -C. Jay Kuo},

url = {http://ict.usc.edu/pubs/Adaptive%20Karhunen-Loeve%20Transform%20for%20Enhanced%20Multichannel%20Audio%20Coding.pdf},

year  = {2001},

date = {2001-01-01},

booktitle = {SPIE},

address = {San Diego, CA},

abstract = {A modified MPEG Advanced Audio Coding (AAC) scheme based on the Karhunen-Loeve transform (KLT) to remove inter-channel redundancy, which is called the MAACKL method, has been proposed in our previous work. However, a straightforward coding of elements of the KLT matrix generates about 240 bits per matrix for typical 5 channel audio contents. Such an overhead is too expensive so that it prevents MAACKL from updating KLT dynamically in a short period of time. In this research, we study the de-correlation efficiency of adaptive KLT as well as an efficient way to encode elements of the KLT matrix via vector quantization. The effect due to different quantization accuracy and adaptation period is examined carefully. It is demonstrated that with the smallest possible number of bits per matrix and a moderately long KLT adaptation time, the MAACKL algorithm can still generate a very good coding performance.},

keywords = {},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{debevec_acquiring_2000,

title = {Acquiring the Reflectance Field of a Human Face},

author = {Paul Debevec and Tim Hawkins and Chris Tchou and Haarm-Pieter Duiker and Westley Sarokin},

url = {http://ict.usc.edu/pubs/Acquiring%20the%20Re%EF%AC%82ectance%20Field%20of%20a%20Human%20Face.pdf},

year  = {2000},

date = {2000-07-01},

booktitle = {SIGGRAPH},

address = {New Orleans, LA},

abstract = {We present a method to acquire the reflectance field of a human face and use these measurements to render the face under arbitrary changes in lighting and viewpoint. We first acquire images of the face from a small set of viewpoints under a dense sampling of incident illumination directions using a light stage. We then construct a reflectance function image for each observed image pixel from its values over the space of illumination directions. From the reflectance functions, we can directly generate images of the face from the original viewpoints in any form of sampled or computed illumination. To change the viewpoint, we use a model of skin reflectance to estimate the appearance of the reflectance functions for novel viewpoints. We demonstrate the technique with synthetic renderings of a person's face under novel illumination and viewpoints.},

keywords = {Graphics},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{bharitkar_selective_2000,

title = {Selective Signal Cancellation for Multiple Listener Audio Applications: An Information Theory Approach},

author = {Sunil Bharitkar and Chris Kyriakakis},

url = {http://ict.usc.edu/pubs/SELECTIVE%20SIGNAL%20CANCELLATION%20FOR%20MULTIPLE-LISTENER%20AUDIO%20APPLICATIONS-%20AN%20INFORMATION%20THEORY%20APPROACH.pdf},

year  = {2000},

date = {2000-07-01},

booktitle = {IEEE International Conference Multimedia and Expo},

address = {New York, NY},

abstract = {Selectively canceling signals at specific locations within an acoustical environment with multiple listeners is of significant importance for home theater, teleconferencing, office, industrial and other applications. The traditional noise cancellation approach is impractical for such applications because it requires sensors that must be placed on the listeners. In this paper we propose an alternative method to minimize signal power in a given location and maximize signal power in another location of interest. A key advantage of this approach would be the need to eliminate sensors. We investigate the use of an information theoretic criterion known as mutual information to design filter coefficients that selectively cancel a signal in one audio channel, and transmit it in another (complementary) channel. Our results show an improvement in power gain at one location in the room relative to the other.},

keywords = {},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{gratch_human-like_2000,

title = {Human-like behavior, alas, demands human-like intellect},

author = {Jonathan Gratch},

url = {http://ict.usc.edu/pubs/Human-like%20behavior%20alas%20demands%20human-like%20intellect.pdf},

year  = {2000},

date = {2000-06-01},

booktitle = {Agents 2000 Workshop on Achieving Human-like Behavior in Interactive Animated Agents},

address = {Barcelona, Spain},

keywords = {Virtual Humans},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{hill_flexible_2000,

title = {Flexible Group Behavior: Virtual Commanders for Synthetic Battlespaces},

author = {Randall W. Hill and Jonathan Gratch and Paul Rosenbloom},

url = {http://ict.usc.edu/pubs/Flexible%20Group%20Behavior-%20Virtual%20Commanders%20for%20Synthetic%20Battlespaces.pdf},

year  = {2000},

date = {2000-06-01},

booktitle = {Proceedings of the 4th International Conference on Autonomous Agents},

address = {Barcelona, Spain},

abstract = {This paper describes a project to develop autonomous commander agents for synthetic battlespaces. The commander agents plan missions, monitor their execution, and replan when necessary. To reason about the social aspects of group behavior, the commanders take various social stances that enable them to collaborate with friends, exercise or defer to authority, and thwart their foes. The purpose of this paper is to describe these capabilities and how they came to be through a series of lessons learned while developing autonomous agents for this domain.},

keywords = {CogArch, Cognitive Architecture, Social Simulation, Virtual Humans},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{kim_how_2000,

title = {How Long Can an Agent Look Away From a Target?},

author = {Youngjun Kim and Randall W. Hill and Jonathan Gratch},

url = {http://ict.usc.edu/pubs/how%20long%20can%20you%20look%20away%20from%20a%20target.pdf},

year  = {2000},

date = {2000-05-01},

booktitle = {9th Conference on Computer Generated Forces and Behavioral Representation},

abstract = {Situation awareness (SA) is the perception of the elements in the environment within a volume of time and space, the comprehension of their meaning, and the projection of their status in the near future [3]. Although the impact of situation awareness and assessment on humans in complex systems is clear, no one theory for SA has been developed. A critical aspect of the SA problem is that agents must construct an overall view of a dynamically changing world using limited sensor channels. For instance, a (virtual) pilot, who visually tracks the location and direction of several vehicles that he cannot see simultaneously, must shift its visual field of view to scan the environment and to sense the situation involved. How he directs his attention, for how long, and how he efficiently reacquires targets is the central question we address in this paper. We describe the perceptual coordination that helps a virtual pilot efficiently track one or more objects. In SA, it is important for a virtual pilot having a limited visual field of view to gather more information from its environment and to choose appropriate actions to take in the environment without losing the target.},

keywords = {Virtual Humans},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{georgiou_multiple_2000,

title = {A Multiple Input Single Output Model for Rendering Virtual Sound Sources in Real Time},

author = {Panayiotis G. Georgiou and Chris Kyriakakis},

url = {http://ict.usc.edu/pubs/A%20MULTIPLE%20INPUT%20SINGLE%20OUTPUT%20MODEL%20FOR%20RENDERING%20VIRTUAL%20SOUND%20SOURCES%20IN%20REAL%20TIME.pdf},

year  = {2000},

date = {2000-01-01},

booktitle = {Proceedings of ICME 2000},

address = {New York, NY},

abstract = {Accurate localization of sound in 3-D space is based on variations in the spectrum of sound sources. These variations arise mainly from reflection and diffraction effects caused by the pinnae and are described through a set of Head-Related Transfer Functions (HRTF’s) that are unique for each azimuth and elevation angle. A virtual sound source can be rendered in the desired location by filtering with the corresponding HRTF for each ear. Previous work on HRTF modeling has mainly focused on the methods that attempt to model each transfer function individually. These methods are generally computationally-complex and cannot be used for real-time spatial rendering of multiple moving sources. In this work we provide an alternative approach, which uses a multiple input single output state space system to creat a combined model of the HRTF’s for all directions. This method exploits the similarities among the different HRTF’s to achieve a significant reduction in the model size with a minimum loss of accuracy.},

keywords = {},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{gratch_emile_2000,

title = {Èmile: Marshalling Passions in Training and Education},

author = {Jonathan Gratch},

url = {http://ict.usc.edu/pubs/Emile-%20Marshalling%20Passions%20in%20Training%20and%20Education.pdf},

year  = {2000},

date = {2000-01-01},

booktitle = {Proceedings of the 4th International Conference on Autonomous Agents},

pages = {325–332},

address = {Barcelona, Spain},

abstract = {Emotional reasoning can be an important contribution to automated tutoring and training systems. This paper describes �mile, a model of emotional reasoning that builds upon existing approaches and significantly generalizes and extends their capabilities. The main contribution is to show how an explicit planning model allows a more general treatment of several stages of the reasoning process. The model supports educational applications by allowing agents to appraise the emotional significance of events as they relate to students' (or their own) plans and goals, model and predict the emotional state of others, and alter behavior accordingly.},

keywords = {Virtual Humans},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{gratch_modeling_2000,

title = {Modeling the Interplay Between Emotion and Decision-Making},

author = {Jonathan Gratch},

url = {http://ict.usc.edu/pubs/Modeling%20the%20Interplay%20Between%20Emotion%20and%20Decision-Making.pdf},

year  = {2000},

date = {2000-01-01},

booktitle = {Proceedings of the 9th Conference on Computer Generated Forces and Behavioral Representation},

abstract = {Current models of computer-generated forces are limited by their inability to model many of the moderators that influence the performance of real troops in the field such as the effects of stress, emotion, and individual differences. This article discusses an extension to our command and control modeling architecture that begins to address how behavioral moderators influence the command decision-making process. Our Soar-Cfor command architecture was developed under the STOW and ASTT programs to support distributed command and control decision-making in the domain of army aviation planning. We have recently extended this architecture to model how people appraise the emotional significance of events and how these events influence decision making.},

keywords = {Virtual Humans},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{scholer_learning_2000,

title = {Learning Domain Knowledge for Teaching Procedural Tasks},

author = {Andrew Scholer and Jeff Rickel and Richard Jr. Angros and W. Lewis Johnson},

url = {http://ict.usc.edu/pubs/Learning%20Domain%20Knowledge%20for%20Teaching%20Procedural%20Tasks.pdf},

year  = {2000},

date = {2000-01-01},

booktitle = {AAAI-2000 Fall Symposium on Learning How to Do Things},

abstract = {Providing domain knowledge needed by intelligent tutoring systems to teach a procedure to students is traditionally a difficult and time consuming task. This paper presents a system for making this process easier by allowing the automated tutor to acquire the knowledge it needs through a combination of programming by demonstration, autonomous experimentation, and direct instruction.},

keywords = {},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{bharitkar_eigenfilters_2000,

title = {Eigenfilters for Signal Cancellation},

author = {Sunil Bharitkar and Chris Kyriakakis},

url = {http://ict.usc.edu/pubs/EIGENFILTERS%20FOR%20SIGNAL%20CANCELLATION.pdf},

year  = {2000},

date = {2000-01-01},

booktitle = {International Symposium on Intelligent Signal Processing and Communication Systems (ISPACS)},

address = {Hawaii},

abstract = {Selectively canceling signals at specific locations within an acoustical environment with multiple listeners is of significant importance for home theater, automobile, teleconferencing, office, industrial and other applications. The traditional noise cancellation approach is impractical for such applications because it requires sensors that must be placed on the listeners. In this paper we investigate the theoretical properties of eigenfilters for signal cancellation proposed in [1]. We also investigate the sensitivity of the eigenfilter as a function of the room impulse response duration. Our results show that with the minimum phase model for the room impulse response, we obtain a better behaviour in the sensitivity of the filter to the duration of the room response.},

keywords = {},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{srinivasamurthy_efficient_2000,

title = {Efficient Scalable Speech Compression for Scalable Speech Recognition},

author = {Naveen Srinivasamurthy and Antonio Ortega and Shrikanth Narayanan},

url = {http://ict.usc.edu/pubs/Efficient%20Scalable%20Speech%20Compression%20for%20Scalable%20Speech%20Recognition.pdf},

year  = {2000},

date = {2000-01-01},

booktitle = {Proceedings of the IEEE Conference on Multimedia and Expo},

abstract = {We propose a scalable recognition system for reducing recognition complexity. Scalable recognition can be combined with scalable compression in a distributed speech recognition (DSR) application to reduce both the computational load and the bandwidth requirement at the server. A low complexity preprocessor is used to eliminate the unlikely classes so that the complex recognizer can use the reduced subset of classes to recognize the unknown utterance. It is shown that by using our system it is fairly straightforward to trade-off reductions in complexity for performance degradation. Results of preliminary experiments using the TI-46 word digit database show that the proposed scalable approach can provide a 40% speed up, while operating under 1.05 kbps, compared to the baseline recognition using uncompressed speech.},

keywords = {},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{georgiou_alpha-stable_1999,

title = {Alpha-Stable Modeling of Noise and Robust Time- Delay Estimation in the Presence of Impulsive Noise},

author = {Panayiotis G. Georgiou and Panagiotis Tsakalides and Chris Kyriakakis},

url = {http://ict.usc.edu/pubs/Alpha-Stable%20Modeling%20of%20Noise%20and%20Robust%20Time-%20Delay%20Estimation%20in%20the%20Presence%20of%20Impulsive%20Noise.pdf},

year  = {1999},

date = {1999-09-01},

booktitle = {IEEE Transactions on Multimedia},

volume = {1},

pages = {291–301},

abstract = {A new representation of audio noise signals is proposed, based on symmetric-stable (S S) distributions in order to better model the outliers that exist in real signals. This representation addresses a shortcoming of the Gaussian model, namely, the fact that it is not well suited for describing signals with impulsive behavior. The stable and Gaussian methods are used to model measured noise signals. It is demonstrated that the stable distribution, which has heavier tails than the Gaussian distribution, gives a much better approximation to real-world audio signals. The significance of these results is shown by considering the time delay estimation (TDE) problem for source localization in teleimmersion applications. In order to achieve robust sound source localization, a novel time delay estimation approach is proposed. It is based on fractional lower order statistics (FLOS), which mitigate the effects of heavy-tailed noise. An improvement in TDE performance is demonstrated using FLOS that is up to a factor of four better than what can be achieved with second-order statistics.},

keywords = {},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{gratch_continuous_1999,

title = {Continuous Planning and Collaboration for Command and Control in Joint Synthetic Battlespaces},

author = {Jonathan Gratch and Randall W. Hill},

url = {http://ict.usc.edu/pubs/Continuous%20Planning%20and%20Collaboration%20for%20Command%20and%20Control%20in%20Joint%20Synthetic%20Battlespaces.pdf},

year  = {1999},

date = {1999-05-01},

booktitle = {Proceedings of the 8th Conference on Computer Generated Forces and Behavioral Representation},

address = {Orlando, FL},

abstract = {In this paper we describe our efforts to model command and control entities for Joint Synthetic Battlespaces. Command agents require a broader repertoire of capabilities than is typically modeled in simulation. They must develop mission plans involving multiple subordinate units, monitor execution, dynamically modify mission plans in response to situational contingencies, collaborate with other decision makers, and deal with a host of organizational issues. We describe our approach to command agent modeling that addresses a number of these issues through its continuous and collaborative approach to mission planning.},

keywords = {Social Simulation, Virtual Humans},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{gratch_deriving_1999,

title = {Deriving Priority Intelligence Requirements for Synthetic Command Entities},

author = {Jonathan Gratch and Stacy C. Marsella and Randall W. Hill and LTC George Stone III},

url = {http://ict.usc.edu/pubs/Deriving%20Priority%20Intelligence%20Requirements%20for%20Synthetic%20Command%20Entities.pdf},

year  = {1999},

date = {1999-05-01},

booktitle = {Proceedings of the 8th Conference on Computer Generated Forces and Behavioral Representation},

address = {Orlando, FL},

abstract = {Simulation-based training is using increasingly complex synthetic forces. As more complex multiechelon synthetic forces are employed in simulations, the need for a realistic model of their command and control behavior becomes more urgent. In this paper we discuss one key component of such a model, the autonomous generation and use of priority intelligence requirements within multi-echelon plans.},

keywords = {Social Simulation, Virtual Humans},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{gratch_why_1999,

title = {Why You Should Buy an Emotional Planner},

author = {Jonathan Gratch},

url = {http://ict.usc.edu/pubs/Why%20You%20Should%20Buy%20an%20Emotional%20Planner.pdf},

year  = {1999},

date = {1999-01-01},

booktitle = {Proceedings of the Agents '99 Workshop on Emotion-Based Agent Architectures},

abstract = {Computation models of emotion have begun to address the problem of how agents arrive at a given emotional state, and how that state might alter their reactions to the environment. Existing work has focused on reactive models of behavior and does not, as of yet, provide much insight on how emotion might relate to the construction and execution of complex plans. This article focuses on this later question. I present a model of how agents ap- praise the emotion significance of events that illustrates a complementary relationship between classical planning methods and models of emotion processing. By building on classical planning methods, the model clarifies prior accounts of emotional appraisal and extends these ac- counts to handle the generation and execution of com- plex multi-agent plans.},

keywords = {Virtual Humans},

pubstate = {published},

tppubtype = {inproceedings}

}