17397024
Multi-level secure video streaming over SRTP
In this paper, we propose a set of solutions to four different levels on data selection for encrypting Motion JPEG video frames over SRTP. These solutions are based on our intensive analysis of the JPEG image compression procedure. We select the most important data which contains most information of an image for encryption; in consequence provide a set of balances between security and computation for different hardware environments. Extensive experiments are conducted and performance data has been analyzed to evaluate the proposed solutions. Results show that these solutions are well suited in different scenarios with various computation power and security requirements.
16274066
Density-based multipath secure communication over mobile ad hoc networks
Security is a critical issue in mobile ad hoc networks (MANETs), where mobile nodes communicate with each other over relatively unreliable wireless links with no fixed infrastructure. One example of this occurs on battle fields, where soldiers often wear cameras and wireless mobile devices to send or receive images/video of different angles or locations in order to obtain better observation of the area. Such an environment could be highly insecure since an enemy could place devices to eavesdrop on or compromise the soldier nodes. In this paper, we consider a case where time sensitive multimedia is sent using multiple paths which can make better use of load balancing strategies, increase bandwidth and save node energy. However, an enemy node could listen in on more than one path at the same time, allowing it to collect sufficient shares of an image or video frame to recover the image. Our proposed algorithm is based on a quantitative analysis of security to protect against such multi-path eavesdropping. We prove that our algorithm can achieve better level of security by detouring traffic via paths without or with less vulnerable areas at the same amount of redundancy. On the other hand, we also prove, using simulation results and mathematical derivation, our algorithm can provide much more redundancy for better multimedia quality purpose while at the same time guaranteeing the same level of security.
28385041
A Modular System for the Classification of Time Series Data
While the field of classification is witnessing excellent achievement in recent years, not much attention is given to methods that deal with the time series data. In this paper, we propose a modular system for the classification of time series data. The proposed approach explores the diversity through various input representation techniques, each of which focuses on a certain aspect of the temporal patterns. The temporal patterns are identified by aggregation of the decisions of multiple classifiers trained through different representations of the input data. Several time series data sets are employed to examine the validity of the proposed approach. The results obtained from our experiments show that the performance of the proposed approach is effective as well as robust.
190958
Reinforcement learning and aggregation
Reinforcement learning (RL) is a learning technique that provides a means for learning an optimal control policy when the dynamics of the environment under consideration is unavailable [L.P. Kaelbling et al., 1996, R.S. Sutton and A.G. Barto, 1998]. While RL has been successfully applied in many single or multiple agents systems [S. Arai et al., 2000, H.R. Berenji and D.A. Vengerov, 2000, M. Tan, 1993, Y. Nagayuki et al., 2000], the learning quality is greatly influenced by learning algorithms and their parameters. Setting of the parameters of RL algorithms is something of a black art, and small differences in these parameters can lead to large differences in learning qualities. Determining the best algorithm and the optimal parameters can be costly in terms of time and computation. Even if the cost is acceptable, the robustness of learning is still a question. In order to address the difficulty, an aggregated multiagent reinforcement learning system (AMRLS) is proposed to deal with the RL environment as a multiagent environment. A maze world environment is used to validate the AMRLS. Experimental results illustrate that compared with normal Q(/spl lambda/)-learning and SARSA(/spl lambda/) algorithms, the AMRLS increases both the learning speed and the rate of reaching the shortest path.
2909075
Design of Multiple Classifier Systems for Time Series Data
In previous work, we showed that the use of Multiple Input Representation(MIR) for the classification of time series data provides complementary information that leads to better accuracy. [4]. In this paper, we introduce the Static Minimization-Maximization approach to build Multiple Classifier Systems(MCSs) using MIR. SMM consists of two steps. In the minimization step, a greedy algorithm is employed to iteratively select the classifiers from the knowledge space to minimize the training error of MCSs. In the maximization step, a modified version of Behavior Knowledge Space(BKS), Balanced Behavior Knowledge Space(BBKS), is used to maximize the expected accuracy of the whole system given that the training error is minimized. Several popular techniques including AdaBoost, Bagging and Random Subspace are used as the benchmark to evaluate the proposed approach on four time series data sets. The results obtained from our experiments show that the performance of the proposed approach is effective as well as robust for the classification of time series data. In addition, this approach could be further extended to other applications in our future research.
653913
Utilizing gestures to better understand dynamic structure of human communication
<b>Motivation:</b> Many researchers have highlighted the importance of gesture in natural human communication. McNeill [4] puts forward the hypothesis that gesture and speech stem from the same mental process and so tend to be both temporally and semantically related. However in contrast to speech, which surfaces as a linear progression of segments, sounds, and words, gestures appear to be nonlinear, holistic, and imagistic. Gesture adds an important dimension to language understanding due to this property of sharing a common origin with speech while using a very different mechanism for transferring information. Ignoring this information when constructing a model of human communication would limit its potential effectiveness.
 <b>Goal and Method:</b> This thesis concerns the development of methods to effectively incorporate gestural information from a human communication into a computer model to more accurately interpret the content and structure of that communication. Levelt [5] suggests that structure in human communication stems from the dynamic conscious process of language production, during which a conversant organizes the concepts to be expressed, plans the discourse, and selects appropriate words, prosody, and gestures while also correcting errors that occur in this process. Clues related to this conscious processing emerge in both the final speech stream and gestures. This thesis will attempt to utilize these clues to determine the structural elements of human-to-human dialogs, including sentence boundaries, topic boundaries, and disfluency structure. For this purpose, the data driven approach is used. This work requires three important components: corpus generation, feature extraction, and model construction.
 <b>Previous Work:</b> Some work related to each of these components has already been conducted. A data collection and processing protocol for constructing multimodal corpora has been created; details on the video and audio processing can be found in the <i>Data and Annotation</i> section of [3]. To improve the speed of producing a corpus while maintaining its quality, we have surveyed factors impacting the accuracy of forced alignments of transcriptions to audio files [2]. These alignments provide a crucial temporal synchronization between video events and spoken words (and their components) for this research effort. We have also conducted measurement studies in an attempt to understand how to model multimodal conversations. For example, we have investigated the types of gesture patterns that occur during speech repairs [1]. Recently, we constructed a preliminary model combining speech and gesture features for detecting sentence boundaries in videotaped dialogs. This model combines language and prosody models together with a simple gestural model to more effectively detect sentence boundaries [3].
 <b>Future Work:</b> To date, our multimodal corpora involve human monologues and dialogues (see http://vislab.cs.wright.edu/kdi). We are participating in the collection and preparation of a corpus of multi-party meetings (see http://vislab.cs.wright.edu/Projects/Meeting-Analysis). To facilitate the multi-channel audio processing, we are constructing a tool to support accurate audio transcription and alignment. The data from this meeting corpus will enable the development of more sophisticated gesture models allowing us to expand the set of gesture features (e.g., spatial properties of the tracked gestures). Additionally, we will investigate more advanced machine learning methods in an attempt to improve the performance of our models. We also plan to expand our models to phenomena such as topic segmentation.
115285526
Proceedings of the APWeb/WAIM 2007 DBMAN, WebETrends, PAIS and ASWAN international workshops on Advances in Web and Network Technologies, and Information Management