ppxscal/embedding_network huggingface dataset:
On the use of conjugate cyclo-stationarity: a blind second-order multi-user equalization method
Authors: A. Chevreuil
Venue: Proceedings of the Acoustics, Speech, and Signal Processing, 1996. on Conference Proceedings., 1996 IEEE International Conference - Volume 05 (1996)

Mainly motivated by the challenging problem of the increase of mobile radio network capacity, some authors have addressed the so-called multi-user blind equalization problem. In this context, p independent users are assumed to share the same carrier frequency as well as the same linear modulation in order to transmit several messages on the same frequency channel. It is then necessary to retrieve the symbols emitted by each user from the received signal in the case where no training sequence is available, and when multipath effects occur. We propose a blind second order method allowing the retrieval of several signals in the context of multipath channels/multi-users. This is achieved by using cycle-stationary and subspace techniques. The simulation results are very encouraging.
Embedded Gossip: Lightweight Online Measurement for Large-Scale Applications
Authors: Wenbin Zhu, Patrick G. Bridges, Arthur B. Maccabe
Venue: Proceedings of the 27th International Conference on Distributed Computing Systems (2007)

For large-scale parallel applications, lightweight online monitoring can enable a wide range of online adaptations, including load balancing, power management, and progress monitoring. The processing and monitoring overhead of centralized global tracing techniques make them unsuitable for such tasks. Purely local tools, on the other hand, fail to provide the global information necessary for many desirable online adaptations of large-scale applications. In this paper, we describe a novel distributed online measurement method for large-scale applications called Embedded Gossip (EG). EG works by piggybacking performance information about application behavior on existing application messages and merging received information with previously known data in a fashion customized to the needs of a particular monitoring task. EG thus provides each process with both local and global views of application behavior with low overhead. To illustrate the capabilities of Embedded Gossip, we also show that it disseminates global information in a timely fashion for a wide range of monitoring tasks, including critical path profiling, workload imbalance monitoring, and progress monitoring. This global information has a wide range of potential uses, including imbalance detection for load balancing and energy management tools, progress monitoring for batch schedulers, and a wide range of other performance debugging and optimization techniques.
Near-optimal selection of encoding parameters for audio coding
Authors: A. Aggarwal
Venue: Proceedings of the Acoustics, Speech, and Signal Processing, 2001. on IEEE International Conference - Volume 05 (2001)

We address the issue of optimizing side information rate for efficient audio coding. In coders such as the MPEG-4 AAC, at rates around 16 kbps to 48 kbps, the side information rate forms a substantial part of the total rate. The parameter search procedure in the verification model optimizes each band separately and results in poor performance at low rates. We propose to jointly optimize the encoding parameter of all the bands. The near-optimal solution using a brute force search has drastic computational complexity. However, the same solution is obtained at a much reduced complexity using a Viterbi search through a trellis. The search procedure is developed and evaluated for two objective measures, the average and the maximum noise-mask ratio. For both the measures, the trellis-based search yields substantially better solutions. In particular, trellis-based optimization of maximum noise-mask ratio greatly improves the performance of AAC at low rates. The resulting bit stream is standard-compatible, and the additional complexity due to the proposed optimization is only incurred at the encoder.
Assessing student learning: it can be more than a survey
Authors: W. K. Dalton
Venue: Proceedings of the Frontiers in Education Conference on 1995. Proceedings., 1995 vol 1. - Volume 01 (1995)

There is a trend toward the assessment of more "outputs" rather than "inputs" in the accreditation processes. The immediate need was to develop an assessment plan to meet the requirements of the North Central Association for future accreditation of the university. Subsequently the desired outputs, student learning outcomes or academic achievements, were defined as what a student can do with their learning. Deciding what constituted these outcomes or achievements was the next step since these were the factors that would be assessed. Many of these factors are subjective in nature and surveys seemed an effective and efficient way to do the assessment. However, the author believes that assessment of student learning outcomes or achievements should begin with instructors taking a reflective look at, i.e., assess, how their students are doing. This process should involve analysis of more than just the exam results. The author has been guided in this process by a course development model he uses which is a modification of models previously published. The steps of this model are explained and his use of it to assess student learning explored. Data which he has collected on his students is discussed. The role this assessment process has played in revisions made to the metallurgy course he teaches are also be discussed. The ACM Portal is published by the Association for Computing Machinery. Copyright © 2010 ACM, Inc. Terms of Usage Privacy Policy Code of Ethics Contact Us Useful downloads: Adobe Acrobat QuickTime Windows Media Player Real Player
Functional coverage - is your design exposed?
Authors: A. Piziali, A. Ziv
Venue: Proceedings of the High-Level Design Validation and Test Workshop, 2005. on Tenth IEEE International (2005)

We prove the correctness of an original method for generating components that capture the occurrence of events, and monitor logical and temporal properties of hardware/software embedded systems. The properties are written in PSL, under the form of assertions in declarative form. The method is based on a library of primitive digital components for the PSL temporal operators. These building blocks are interconnected to construct complex properties, resulting in a synthesizable digital module that can be properly linked to the digital system under scrutiny. The proof reported in this paper applies to the weak version of all "foundation language" operators.
Journal-guided resynchronization for software RAID
Authors: Timothy E. Denehy, Andrea C. Arpaci-Dusseau, Remzi H. Arpaci-Dusseau
Venue: Proceedings of the 4th conference on USENIX Conference on File and Storage Technologies - Volume 4 (2005)

We investigate the problem of slow, scan-based, software RAID resynchronization that restores consistency after a system crash. Instead of augmenting the RAID layer to quicken the process, we leverage the functionality present in a journaling file system. We analyze Linux ext3 and introduce a new mode of operation, declared mode, that guarantees to provide a record of all outstanding writes in case of a crash. To utilize this information, we augment the software RAID interface with a verify read request, which repairs the redundant information for a block. The combination of these features allows us to provide fast, journal-guided resynchronization. We evaluate the effect of journal-guided resynchronization and find that it provides improved software RAID reliability and availability after a crash, while suffering little performance loss during normal operation.
Reengineering the Internet for Better Security
Authors: Manoj Parameswaran, Xia Zhao, Andrew B. Whinston, Fang Fang
Venue: Computer (2007)

The growing proliferation of malware is raising doubts about the Internet's future. Current security measures primarily targetinbound traffic, but service providers have no incentive to stop attacks and spam at the source. A proposed certification schememotivates providers to control outgoing traffic, efficiently increasing overall security while preserving the Internet's open,decentralized structure.
A Fuzzy Technique for Segmentation of Handwritten Bangla Word Images
Authors: Subhadip Basu, Ram Sarkar, Nibaran Das, Mahantapas Kundu, Mita Nasipuri, Dipak Kumar Basu
Venue: Proceedings of the International Conference on Computing: Theory and Applications (2007)

A fuzzy technique for segmentation of handwritten Bangla word images is presented. It works in two steps. In first step, the black pixels constituting the Matra (i.e., the longest horizontal line joining the tops of individual characters of a Bangla word) in the target word image is identified by using a fuzzy feature. In second step, some of the black pixels on the Matra are identified as segment points (i.e., the points through which the word is to be segmented) by using three fuzzy features. On experimentation with a set of 210 samples of handwritten Bangla words, collected from different sources, the average success rate of the technique is shown to be 95.32%. Apart from certain limitations, the technique can be considered as a significant step towards the development of a full-fledged Bangla OCR system, especially for handwritten documents.
Cryptographic voting protocols: a systems perspective
Authors: Chris Karlof, Naveen Sastry, David Wagner
Venue: Proceedings of the 14th conference on USENIX Security Symposium - Volume 14 (2005)

Cryptographic voting protocols offer the promise of verifiable voting without needing to trust the integrity of any software in the system. However, these cryptographic protocols are only one part of a larger system composed of voting machines, software implementations, and election procedures, and we must analyze their security by considering the system in its entirety. In this paper, we analyze the security properties of two different cryptographic protocols, one proposed by Andrew Neff and another by David Chaum. We discovered several potential weaknesses in these voting protocols which only became apparent when considered in the context of an entire voting system. These weaknesses include: subliminal channels in the encrypted ballots, problems resulting from human unreliability in cryptographic protocols, and denial of service. These attacks could compromise election integrity, erode voter privacy, and enable vote coercion. Whether our attacks succeed or not will depend on how these ambiguities are resolved in a full implementation of a voting system, but we expect that a well designed implementation and deployment may be able to mitigate or even eliminate the impact of these weaknesses. However, these protocols must be analyzed in the context of a complete specification of the system and surrounding procedures before they are deployed in any large-scale public election.
Design and evaluation of multi-channel multi-hop wireless networks
Authors: Nitin H. Vaidya
Venue:  (2006)

Wireless networks have been widely deployed in the past few years. With rapidly increasing number of users, it is important to maximize utilization of given resources to achieve high performance. Among many approaches, the aim of this dissertation is in utilizing available frequency spectrum, which may be divided into multiple non-overlapping channels. Particularly, we focus on the case where wireless nodes are equipped with a single network interface, which can operate on any one channel at a given time. Wireless network standards such as IEEE 802.11 provide multiple non-interfering frequency channels, where multiple communications can take place simultaneously. However, current protocols cannot exploit this availability to achieve high performance. The main challenge in utilizing multiple channels is the fact that a node equipped with a single network interface can only operate on a single channel, although it is capable of switching its operating channel. When two nodes want to communicate, they must be operating on the same channel. Thus, to support multiple channels, protocols need to properly assign and coordinate channels among nodes. Without careful design, multi-channel protocols may not be able to achieve higher performance than single-channel protocols. In this disseration, we first identify issues in designing a multi-channel multi-hop network, with the focus on layer-2 and layer-3 protocols. Based on the observations, we develop medium access control (MAC) and routing protocols that can utilize multiple channels with a single interface. Finally, we evaluate the multi-channel protocols through simulation and a prototype implementation.
Fast algorithms for pet image reconstruction and their analysis
Authors: Richard M. Leahy
Venue:  (2006)

Iterative Bayesian image reconstruction can achieve superior image quality compared to analytic image reconstruction by applying an accurate system model and an appropriate data model. However, due to the increased number of detectors in modern PET scanners and higher image resolution required by new applications, the amount of computation in image reconstruction increases faster than computer power, and consequently, conventional iterative Bayesian image reconstruction algorithms are often impractical. Furthermore, the decrease of scan duration in clinical and dynamic reconstruction leads to low count rate data, which deems the traditional data models and analysis methods inappropriate. This dissertation focuses on these challenges to develop more accurate and faster methods for static and dynamic PET image reconstruction. We develop a simple but accurate statistical data model by exploiting the symmetry of the probability mass function of the data. We derive an approximate log-likelihood function using our new statistical data model and develop a new reconstruction method. Simulation results show the approximation improves on earlier methods and the reconstruction results have good bias performance even at very low count rates. Further, we present a method to accurately estimate the Fisher information matrix (FIM), which plays a key role in the analysis of reconstructed images and cannot be precisely computed by conventional methods when the count rate is small. We also demonstrate the resulting FIM can be applied to control the reconstructed image quality. To reduce the run time caused by increasing computation load, we apply the incremental optimization transfer method to static PET image reconstruction and develop a fast hybrid reconstruction algorithm using it with incremental gradient methods and conjugate gradient methods. Through automatic selection of the point at which we switch between these three algorithms, we achieve faster convergence than individual algorithms. For dynamic reconstruction, we describe a fast globally convergent fully 4D incremental gradient algorithm to estimate the continuous-time tracer density from list mode PET data. Fully 4D simulations demonstrate the convergence of the algorithm for a high count data set on a 4-ring scanner.
Identifying a control function in parabolic partial differential equations from overspecified boundary data
Authors: Mehdi Tatari, Mehdi Dehghan
Venue: Computers Mathematics with Applications (2007)

Determination of an unknown time-dependent function in parabolic partial differential equations, plays a very important role in many branches of science and engineering. In the current investigation, the Adomian decomposition method is used for finding a control parameter p(t) in the quasilinear parabolic equation u"t=u"x"x+p(t)u+@f, in [0,1]x(0,T] with known initial and boundary conditions and subject to an additional condition in the form of @!"0^1k(x)u(x,t)dx=E(t),0@?t@?T which is called the boundary integral overspecification. The main approach is to change this inverse problem to a direct problem and then solve the resulting equation using the well known Adomian decomposition method. The decomposition procedure of Adomian provides the solution in a rapidly convergent series where the series may lead to the solution in a closed form. Furthermore due to the rapid convergence of Adomian's method, a truncation of the series solution with sufficiently large number of implemented components can be considered as an accurate approximation of the exact solution. This method provides a reliable algorithm that requires less work if compared with the traditional techniques. Some illustrative examples are presented to show the efficiency of the presented method.
Statistical fuzzy interval neural networks for currency exchange rate time series prediction
Authors: Yan-Qing Zhang, Xuhui Wan
Venue: Applied Soft Computing (2007)

In this paper, the statistical fuzzy interval neural network with statistical interval input and output values is proposed to perform statistical fuzzy knowledge discovery and the currency exchange rate prediction. Time series data sets are grouped into time series data granules with statistical intervals. The statistical interval data sets including week-based averages, maximum errors of estimate and standard deviations are used to train the fuzzy interval neural network to discover fuzzy IF-THEN rules. The output of the fuzzy interval neural network is an interval value with certain percent confidence. Simulations are completed in terms of the exchange rates between US Dollar and other three currencies (Japanese Yen, British Pound and Hong Kong Dollar). The simulation results show that the fuzzy interval neural network can provide more tolerant prediction results.
Aggregation Dynamics in Service Overlay Networks
Authors: Pietro Michiardi, Paul Marrow, Richard Tateson, Fabrice Saffre
Venue: Proceedings of the First International Conference on Self-Adaptive and Self-Organizing Systems (2007)

In this work we analyze the characteristics of service overlay networks generated by uncoordinated service providers that deploy different service replicas on overlay nodes across the Internet. Our approach differs from previous works, that generally rely on application-level routing, in that we allow nodes to autonomously re-wire the service overlay to make it capable of absorbing a heterogeneously distributed workload that would otherwise result in some nodes with a specific service being overloaded and others remaining idle. We provide a game theoretic model of the overlay creation process and propose several optimization methods to achieve Nash equilibrium topologies. Equilibrium overlays are characterized by interconnected clusters of nodes that instantiate the same service replicas. Hindered by the computational complexity of finding stable wirings, we propose a simple distributed heuristic that allows the study of overlay networks with a realistic size and with several service instances. We show the ability of our re-wiring strategy to promote the emergence of a clustered global topology whilst running locally. We also argue that the lack of incentives for nodes to participate in the overlay creation might lead to several types of misbehavior, of which some representative cases are analyzed. Finally, both scalability and diversity (in terms of service instances) issues that might affect our distributed heuristic are evaluated in detail.
Learning from interpretations: a rooted kernel for ordered hypergraphs
Authors: Gabriel Wachman, Roni Khardon
Venue: Proceedings of the 24th international conference on Machine learning (2007)

The paper presents a kernel for learning from ordered hypergraphs, a formalization that captures relational data as used in Inductive Logic Programming (ILP). The kernel generalizes previous approaches to graph kernels in calculating similarity based on walks in the hypergraph. Experiments on challenging chemical datasets demonstrate that the kernel outperforms existing ILP methods, and is competitive with state-of-the-art graph kernels. The experiments also demonstrate that the encoding of graph data can affect performance dramatically, a fact that can be useful beyond kernel methods.
A method for teaching problem assessment [engineering education]
Authors: J. A. Stuart
Venue: Proceedings of the Frontiers in Education Conference,1997. on 27th Annual Conference. Teaching and Learning in an Era of Change. - Volume 01 (1997)

In practice, engineers face open-ended problems that they must define and solve. In contrast, engineering class assignments are often well defined. In order to facilitate student learning in exploring and formulating problems, an interactive assignment structure is proposed. In this paper, a project assignment structure is presented to encourage students to ask questions, to cross disciplines in seeking information, and to be creative in defining a problem and developing solution alternatives. A specific implementation of the proposed method is described.
A Lightweight Mechanism for Dependable Communication in Untrusted Networks
Authors: Michael Rogers, Saleem Bhatti
Venue: Proceedings of the 37th Annual IEEE/IFIP International Conference on Dependable Systems and Networks (2007)

We describe a method for enabling dependable forwarding of messages in untrusted networks. Nodes perform only relatively lightweight operations per message, and only the originator and destination need to trust each other. Whereas existing protocols for dependable communication rely on establishing a verifiable identity for every node, our protocol can operate in networks with unknown or varying membership and with no limits on the creation of new identities. Our protocol supports the maintenance of unlinkability: relays cannot tell whether a given originator and destination are communicating. The destination of each message generates an unforgeable acknowledgement (U-ACK) that allows relays and the originator to verify that the message was delivered unmodified to the destination, but relays do not need to share keys with the originator or destination, or to know their identities. Similarly, the endpoints do not need to know the identities of the relays. U-ACKs can be seen as a building block for dependable communication systems; they enable nodes to measure the level of service provided by their neighbours and optionally to adjust the level of service they provide in return, creating an incentive for nodes to forward messages. Our work is ongoing.
Rapid prototyping of multimedia chip sets
Authors: M. Ben-Romdhane
Venue: Proceedings of the Acoustics, Speech, and Signal Processing, 1999. on 1999 IEEE International Conference - Volume 04 (1999)

We have developed a rapid prototyping environment for multimedia applications. The design environment is based on efficient hardware and software reuse, abstraction, design parameterization, and automation. The design methodology maintains a flexible boundary between hardware and software by eliminating hardware fabrication from the design loop. A reusable hardware/software library for video compression has been developed to support the design methodology. We present a case study involving the design of an H.263-based video decoder. This case study illustrates the efficiency and flexibility of the design methodology.