ppxscal/embedding_network huggingface dataset:
Improving access to organized information
Authors: Micah Adler
Venue:  (2006)

We introduce several new models and methods for improving access to organized information. The first model, Constrained Subtree Selection (CSS), has applications in web site design and the reorganization of directory structures. Given a hierarchy represented as a rooted DAG G with n weighted leaves, one selects a subtree of the transitive closure of G that minimizes the expected path cost. Path cost is the sum of the degree costs along a path from the root to a leaf. Degree cost, &gamma;, is a function of the out degree of a node. We give a sufficient condition for &gamma; that makes CSS NP-complete. This result holds even when the leaves have equal weight. Turning to algorithms, we give a polynomial time solution for instances of CSS where G does not constrain the choice of subtrees and &gamma; favors nodes with at most k links. Even though CSS remains NP-hard for constant degree DAGs, we give an O(log(k)&gamma;(d+1)) approximation for any G with maximum degree d, provided that &gamma; favors nodes with at most k links. Finally, we give a complete characterization of the optimal trees for two special cases: (1) linear degree cost in unconstrained graphs and uniform probability distributions, and (2) logarithmic degree cost in arbitrary DAGs and uniform probability distributions. The second problem, Category Tree (CT), seeks a decision tree for categorical data where internal nodes are categories, edges are appropriate values for the categories, and leaves are data items. CT generalizes the well-studied Decision Tree (DT) problem. Our results resolve two open problems: We give a ln n + 1-approximation for DT and show DT does not have a polynomial time approximation scheme unless P=NP. Our work, while providing the first non-trivial upper and lower bounds on approximating DT, also demonstrates that DT and a subtly different problem which also bears the name decision tree have fundamentally different approximation complexity. We complement the above models with a new pruning method for k nearest neighbor queries on R-trees. We show that an extension to a popular depth-first 1-nearest neighbor query results in a theoretically better search. We call this extension Promise-Pruning and construct a class of R-trees where its application reduces the search space exponentially.
A fast motion estimation algorithm equivalent to exhaustive search
Authors: M. Gharavi-Alkhansari
Venue: Proceedings of the Acoustics, Speech, and Signal Processing, 200. on IEEE International Conference - Volume 02 (2001)

A fast algorithm is proposed for block motion estimation for video sequences. The proposed algorithm is proven to be equivalent to exhaustive search. In a multiresolution approach, it uses a mathematically derived threshold to prune search candidates whose low-resolution versions are too far from the low resolution version of the block for which a best match is sought. Experimental results show that speed ups of around 36, compared to full search, may be achieved, for some typical test video sequences. This is the fastest full-search-equivalent motion estimation reported in the literature to date, and has speed ups comparable to inexact fast motion estimation methods. 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
Further explorations in text alignment with handwritten documents
Authors: E. Micah Kornfield, R. Manmatha, James Allan
Venue: International Journal on Document Analysis and Recognition (2007)

Today's digital libraries increasingly include not only printed text but also scanned handwritten pages and other multimedia material. There are, however, few tools available for manipulating handwritten pages. Here, we extend our algorithm from [5]based on dynamic time warping (DTW) for a word by word alignment of handwritten documents with (ASCII) transcripts. We specifically attempt to incorporate language modelling and parameter training into our algorithm. In addition, we take a critical look at our evaluation metrics. We see at least three uses for such alignment algorithms. First, alignment algorithms allow us to produce displays (for example on the web) that allow a person to easily find their place in the manuscript when reading a transcript. Second, such alignment algorithms will allow us to produce large quantities of ground truth data for evaluating handwriting recognition algorithms. Third, such algorithms allow us to produce indices in a straightforward manner for handwriting material. We provide experimental results of our algorithm on a set of 100 pages of historical handwritten material&#x2013;specifically the writings of George Washington. Our method achieves average F-measure values of 68.3 online by line alignment and 57.8 accuracy when aligning whole pages at time.
JVM susceptibility to memory errors
Authors: Deqing Chen, Alan Messer, Philippe Bernadat, Guangrui Fu, Zoran Dimitrijevic, David Jeun Fung Lie, Durga Mannaru, Alma Riska, Dejan Milojicic
Venue: Proceedings of the 2001 Symposium on JavaTM Virtual Machine Research and Technology Symposium - Volume 1 (2001)

Modern computer systems are becoming more powerful and are using larger memories. However, except for very high end systems, little attention is being paid to high availability. This is particularly true for transient memory errors, which typically cause the entire system to fail. We believe that this situation can be improved by addressing memory errors at all levels of the system, bring commodity systems closer to mainframe-class availability. In this paper, we use fault injection experiments to investigate memory error susceptibility at the highest level using a JVM and four Java benchmark applications. We then consider JVM data structure checksums to increase detection of silent data corruption affecting the JVM and applications. Our results indicate that the JVM's heap area has a higher memory error susceptibility than its static data area and that we can detect up to 39% of all memory errors in the JVM and application. We believe that such techniques will allow commodity systems to be made much more robust and less error-prone to transient errors.
Fuzzy anisotropic diffusion for speckle filtering
Authors: S. Aja
Venue: Proceedings of the Acoustics, Speech, and Signal Processing, 200. on IEEE International Conference - Volume 02 (2001)

An anisotropic diffusion filter controlled by fuzzy rules is presented. The proposed filter is based in the Perona-Malik technique, using fuzzy reasoning to calculate the diffusion coefficient which controls the whole diffusion. The method has the advantage that it can be used for both smoothing and noise cleaning, as well as edge enhancement. This new approach also allows us to model the diffusion process through a rule base to have a better performance. Some examples are given to illustrate the effectiveness of the proposed technique.
An OCA-based fast algorithm for 2-D discrete periodized wavelet transform
Authors: King-Chu Hung
Venue: Proceedings of the Acoustics, Speech, and Signal Processing, 1999. on 1999 IEEE International Conference - Volume 06 (1999)

This paper presents a fast algorithm to perform the 2-D discrete periodized wavelet transform based on the operator correlation algorithm (OCA). The OCA-based algorithm needs half of the multiplications and bits required by the classical algorithm. The OCA-based algorithm is modular inherent. It can be easily mapped to VLSI design.
COBEA: a CORBA-based event architecture
Authors: Chaoying Ma, Jean Bacon
Venue: Proceedings of the 4th conference on USENIX Conference on Object-Oriented Technologies and Systems - Volume 4 (1998)

Events are an emerging paradigm for composing applications in an open, heterogeneous distributed world. In Cambridge we have developed scalable event handling based on a publish-register-notify model with event object classes and server-side filtering based on parameter templates. After experience in using this approach in a home-built RPC system we have extended CORBA, an open standard for distributed object computing, to handle events in this way. In this paper, we present the design of COBEA - a COrba-Based Event Architecture. A service that is the source of (parameterised) events publishes in a Trader the events it is prepared to notify, along with its normal interface specification. For scalability, a client must register interest (by invoking a register method with appropriate parameters or wild cards) at the service, at which point an access control check is carried out. Subsequently, whenever a matching event occurs, the client is notified. We outline the requirements on the COBEA architecture, then describe its components and their interfaces. The design and implementation aim to support easy construction of applications by using COBEA components. The components include event primitives, an event mediator and a composite event service; each features well-defined interfaces and semantics for event registration, notification and filtering. We demonstrate that COBEA is flexible in supporting various application scenarios yet handles efficiently the most common event communications. The performance of server-side filtering for various registration scenarios is presented. Our initial experience with applications is also described.
Composing a new ECE program: the first five years
Authors: J. L. Schmalzel
Venue: Proceedings of the Frontiers in Education Conference, 2001. 31st Annual - Volume 02 (2001)

The authors have developed a new Electrical and Computer Engineering (ECE) program at Rowan University, NJ, USA. The first class graduated in May 2000. Features include: a continuous engineering clinic sequence; a mixture of two-, three- and four-credit courses; and technology focus electives. Project-based instruction is employed as a tool for motivating students and to demonstrate the relevancy of material. Multidisciplinary courses provide the opportunity for students in different disciplines to work together. Some of the approaches-and lessons learned-of interest to other start-ups and programs considering transformation.
The effect of polarity inversion of speech on human perception and data hiding as an application
Authors: S. Sakaguchi
Venue: Proceedings of the Acoustics, Speech, and Signal Processing, 2000. on IEEE International Conference - Volume 02 (2000)

In this paper we investigate how polarity inversion of speech signals effects human perception, and we apply this technique for data hiding. In most languages, glottal airflow during phonation is uni-directional, causing constant polarity of the speech waveform. On the other hand, the human auditory system cannot discriminate between speech signals with positive and negative polarity. Based on these facts, we developed an algorithm to hide data in speech signals. We assigned one bit to each syllable of speech, and inverted the polarity of the signal at every syllable according to the assigned bit. We performed a test using 20 sentences from the TIMIT corpus to determine both whether a human could distinguish between the original and polarity-inverted signal and whether we could automatically restore the embedded binary data. We found that we were able to successfully hide data and restore it automatically.
Expanding Gaussian kernels for multivariate conditional density estimation
Authors: D. T. Davis
Venue: Proceedings of the Acoustics, Speech, and Signal Processing, 1996. on Conference Proceedings., 1996 IEEE International Conference - Volume 06 (1996)

We propose a new method to estimate the multivariate conditional density, f(m|x), a density over the output space m conditioned on any given input x. In particular, we are interested in cases where the number of available training data points is relatively sparse within x space. We start from a priori considerations and establish certain desirable characteristics in kernel functions for conditional density estimation. We find that Gaussian kernels with expanding covariances, expanding as we move away from the data point of the kernel, satisfy these a priori considerations. We combine these expanding Gaussian kernels (EGK) according to Bayesian techniques. We compare the EGK with standard Gaussian kernel (SDK) methods, and find that EGK avoids multimodality, has diminishing confidence levels farther from training points, performs better asymptotically, and performs better with respect to the Kullback-Leibler criteria.
Annotations for Defining Interactive Instructions to Interpreter Based Program Visualization Tools
Authors: Essi Lahtinen, Tuukka Ahoniemi
Venue: Electronic Notes in Theoretical Computer Science (ENTCS) (2007)

An interpreter based visualization tool can be used for creating visualization exercises that engage the student to work with the visualization instead of just watching it passively. This article describes how to make the interpreter instruct the student interactively. The idea is to use the interpreter for testing the code that the student has written and give the instructions according to the test results. This only requires minor work for implementation of the visualization tool.
A Distributed Throttling Approach for Handling High Bandwidth Aggregates
Authors: Chee Wei Tan, Dah-Ming Chiu, John C. S. Lui, David K. Y. Yau
Venue: IEEE Transactions on Parallel and Distributed Systems (2007)

Public-access networks need to handle persistent congestion and overload caused by high bandwidth aggregates that may occur during times of flooding-based DDoS attacks or flash crowds. The often unpredictable nature of these two activities can severely degrade server performance. Legitimate user requests also suffer considerably when traffic from many different sources aggregates inside the network and causes congestion. This paper studies a family of algorithms that "proactively” protect a server from overload by installing rate throttles in a set of upstream routers. Based on an optimal control setting, we propose algorithms that achieve throttling in a distributed and fair manner by taking important performance metrics into consideration, such as minimizing overall load variations. Using ns-2 simulations, we show that our proposed algorithms 1) are highly adaptive by avoiding unnecessary parameter configuration, 2) provide max-min fairness for any number of throttling routers, 3) respond very quickly to network changes, 4) are extremely robust against extrinsic factors beyond the system control, and 5) are stable under given delay bounds.
PCP: efficient endpoint congestion control
Authors: Thomas Anderson, Andrew Collins, Arvind Krishnamurthy, John Zahorjan
Venue: Proceedings of the 3rd conference on Networked Systems Design & Implementation - Volume 3 (2006)

In this paper, we present the design, implementation, and evaluation of a novel endpoint congestion control system that achieves near-optimal performance in all likely circumstances. Our approach, called the Probe Control Protocol (PCP), emulates network-based control by using explicit short probes to test and temporarily acquire available bandwidth. Like TCP, PCP requires no network support beyond plain FIFO queues. Our initial experiments show that PCP, unlike TCP, achieves rapid startup, small queues, and low loss rates, and that the efficiency of our approach does not compromise eventual fairness and stability. Further, PCP is compatible with sharing links with legacy TCP hosts, making it feasible to deploy.
Mining System for Community Finding and Centrality of Virtual User Network on the Internet
Authors: Sen Qin, Guan-zhong Dai, Yan-ling Li
Venue: Proceedings of the Sixth IEEE International Conference on Data Mining - Workshops (2006)

Community finding of virtual user network on the Internet has provoked more and more researchers' interests in the field of computer and physics field recently. Existed results focus on how to seek a reasonable and feasible algorithm to find the communities of virtual user network mostly, but scarcely relate to the centrality of those found communities. In addition, the centrality of those found communities is usually not involved. In this paper, the topology of virtual user network is analyzed firstly, and it shows that the network has a scale-free characteristic. The straightforward and effective criterion evaluating the correctness to detect the community structure has been established. Then the mining system for community finding and centrality of the network is designed and its workflow is presented. Two key modules of this system, community finding module and centrality module, are studied in detail. An implementation example is given to verify the validity of the design. Finally, the paper is summarized.
1.2 kbit/s harmonic coder using auditory filters
Authors: M. Kohata
Venue: Proceedings of the Acoustics, Speech, and Signal Processing, 1999. on 1999 IEEE International Conference - Volume 01 (1999)

In this paper, a very low bit speech coder at 1.2 kbps is newly proposed. Like the LPC vocoder, it only requires gain, pitch, and spectral information, but its quality is far superior. The synthesis method is one of harmonic coding, using sinusoids whose frequencies are multiples of the fundamental frequency, where the amplitudes of the sinusoids are adaptively modulated using gammatone filters as a perceptual weighting filter. The sinusoids' phases are also adjusted so as to maximize the perceptual quality. In order to reduce the total bit rate to 1.2 kbit/s, a new segment coder for spectral information (LSP coefficients) using DP matching is also proposed. The quality of the synthesized speech was improved by 0.45 in the mean opinion score (MOS) compared with that of the simple LPC vocoder operating at the same rate, and it was comparable to that of 2.4 kbit/s MELP coder. 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
Cramer Rao bound analysis for data aided time synchronization of MSK over a fast fading channel
Authors: R. Dabora
Venue: Proceedings of the Acoustics, Speech, and Signal Processing, 2000. on IEEE International Conference - Volume 05 (2000)

In this paper we consider a time synchronization problem for a minimum shift keying (MSK) signal received over a time-selective, fast fading channel. We calculate the Cramer Rao bound (CRB) for the case when the transmitted data bits are a-priori known and examine the effects of parameters such as signal-to-noise ratio (SNR) and temporal correlation of the channel on the synchronization performance. In addition, we derive an explicit high SNR approximation to the CRB. Lastly, we use the bound to study how the choice of transmitted bits (the training sequence) influences synchronization performance thus enabling us to identify the best and worst case bit sequences.
pKASSO: Towards Seamless Authentication Providing Non-Repudiation on Resource-Constrained Devices
Authors: Ki-Woong Park, Hyunchul Seok, Kyu-Ho Park
Venue: Proceedings of the 21st International Conference on Advanced Information Networking and Applications Workshops - Volume 02 (2007)

PKI is generally considered as the most appropriate solution for e-commerce and mutual authentication, owing to its digital signature and non-repudiation features. Asymmetric key operations of PKI require by far more CPU cycles than a symmetric cryptographic algorithm. It hampers the usability of PKI on resource-constrained devices. To overcome these limitations, we propose a new PKI-based authentication protocol and security infrastructure enhanced with single sign-on and delegation technology for a device with a restricted computing power. Although a conventional delegation mechanism cannot support nonrepudiation mechanism against malicious user's behavior, our proposed protocol and security infrastructure can provide the mechanism by devising a referee server that generates binding information between a device and authentication messages, and retains the information in its local storage for future accusation.
A design framework of virtual hardware for 3rd generation medium access control protocol
Authors: T. Sammanee, S. Kamolpiwong, S. Chuawong
Venue: Proceedings of the The 8th International Conference on Communication Systems - Volume 01 (2002)

A design framework for virtual hardware of the 3rd generation (3G) medium access control (MAC) protocol has been developed to provide a core-based system for running higher layers without using real hardware. In this framework, a user can create any connections from the user equipment (UE) and sends control commands and data through the UMTS Terrestrial Radio Access Network (UTRAN) side without using real hardware. UTRAN and UE will be emulated by the 3G virtual hardware. All communication channels pass through MAC layer and will be emulated by an Ethernet link. We believe that this tool will give us a better result than using computer simulation, e.g. all signals and data are processed in real-time, as well as more flexibility than using real hardware components, e.g. hardware modification. When, the 3G virtual hardware is un-plugged, the real hardware can be replaced.
A Quantitative analysis of disk drive power management in portable computers
Authors: Kester Li, Roger Kumpf, Paul Horton, Thomas Anderson
Venue: Proceedings of the USENIX Winter 1994 Technical Conference on USENIX Winter 1994 Technical Conference (1994)

With the advent and subsequent popularity of portable computers, power management of system components has become an important issue. Current portable computers implement a number of power reduction techniques to achieve a longer battery life. Included among these is spinning down a disk during long periods of inactivity. In this paper, we perform a quantitative analysis of the potential costs and benefits of spinning down the disk drive as a power reduction technique. Our conclusion is that almost all the energy consumed by a disk drive can be eliminated with little loss in performance. Although on current hardware, reliability can be impacted by our policies, the next generation of disk drives will use technology (such as dynamic head loading) which is virtually unaffected by repeated spinups. We found that the optimal spindown delay time, the amount of time the disk idles before it is spun down, is 2 seconds. This differs significantly from the 3-5 minutes in current practice by industry. We will show in this paper the effect of varying the spindown delay on power consumption; one conclusion is that a 3-5 minute delay results in only half of the potential benefit of spinning down a disk.