ppxscal/embedding_network huggingface dataset:
X-mHMM: An Efficient Algorithm for Training Mixtures of HMMs When the Number of Mixtures Is Unknown
Authors: Zoltan Szamonek, Csaba Szepesvari
Venue: Proceedings of the Fifth IEEE International Conference on Data Mining (2005)

In this paper we consider sequence clustering problems and propose an algorithm for the estimation of the number of clusters based on the X-means algorithm. The sequences are modeled using mixtures of Hidden Markov Models. By means of experiments with synthetic data we analyze the proposed algorithm. This algorithm proved to be both computationally efficient and capable of providing accurate estimates of the number of clusters. Some results of experiments with real-world web-log data are also given.
Photo-to-search: using multimodal queries to search the web from mobile devices
Authors: Xin Fan, Xing Xie, Zhiwei Li, Mingjing Li, Wei-Ying Ma
Venue: Proceedings of the 7th ACM SIGMM international workshop on Multimedia information retrieval (2005)

Nowadays, mobile phones with the digital camera are getting more and more popular. With necessary technologies, they are possible to become a powerful tool to search the Web on the go. Most Web search engines only support text queries. Therefore, users have to convert their information needs into words. However, it is sometimes difficult to describe the needs in text and the text input is inconvenient on small devices. To solve the problem, we propose a system named Photo-to-Search which allows users to input multimodal queries. Particularly, we study queries with captured images and optional text messages in this paper. For example, the user can simply take a photo of the flower and input a few terms like "flower". Textually relevant Web images are retrieved according to the query terms. Afterwards, the snapped picture is compared with these images by the CBIR (Content Based Image Retrieval) method. According to the context of the visually similar images, related key phrases are extracted. Finally, the search results are returned in multiple forms. Our system can also search for very similar images on the Web, such as movie posters or photos of film stars, to find related information. Experimental results on the large scale data showed our system achieved satisfactory efficiency and performance.
A Framework for Testing Web Services and Its Supporting Tool
Authors: Hong Mei, Lu Zhang
Venue: Proceedings of the IEEE International Workshop (2005)

With the increase of the popularity of Web services, more and more Web applications are developed with this new kind of components. This new way of software development brings about new issues for software testing, which has been widely recognized as a realistic means for ensuring the quality of software systems. In this paper, we focus on facilitating the testing of Web services. In particular, we propose a framework for testing Web services, which can help a tester of Web services in two ways: Firstly, it can help the tester to acquire effective test data. Secondly, it can help the tester to execute the test data for the testing. We also discuss some issues for the implementation of its supporting tool. Furthermore, we report an experimental study of our framework. The results can validate the effectiveness of our approach.
Introduction to computer graphics
Authors: Mike Bailey, Andrew Glassner
Venue: ACM SIGGRAPH 2004 Course Notes (2004)

Computer graphics is an exciting field of endeavor, but it is often difficult for a newcomer to get started. This course is that opportunity! The topics being presented will address many areas within computer graphics and treat each from the point of view of "why-do-I-care" and "how-to." Those who take this course will emerge well-prepared to take on further study, including the taking of other SIGGRAPH courses. Attendees will also be ready to take on the vendor show and better appreciate the Electronic Theatre. We hope you enjoy reading and using these notes as much as we enjoyed preparing them.
An Optimal ILP Model for Delay Time to Minimize Peak Power and Area
Authors: Ki-Bog Kim, Chi-Ho Lin
Venue: Proceedings of the Fifth International Workshop on System-on-Chip for Real-Time Applications (2005)

In this paper, we suggested the integer linear programming (ILP) models that went through constraint scheduling to simple cycle operation during the delay time. ILP is applicable depending on operation-delay time, operation type to be used, and datapath form to be constrained, which is required in order to practically apply the scheduling techniques by ILP to datapath. This paper described scheduling constrained to multi ¿ cycle - operation minimizing given resources' peak power and the number of areas under the fixed-time control constraint and ILP model of during the delay time.
Fast DC Analysis and Its Application to Combinatorial Optimization Problems
Authors: Gaurav Trivedi, Madhav P. Desai, H. Narayanan
Venue: Proceedings of the 19th International Conference on VLSI Design held jointly with 5th International Conference on Embedded Systems Design (2006)

Many combinatorial optimization problems such as the min cost flow problem are equivalent to the solution of appropriate DC circuits made up of positive resistors, voltage sources, current sources and ideal diodes. Simulating the DC circuit is an alternative approach to the approximate solution of such problems. However, conventional simulators such as SPICE are too slow for this purpose. This paper describes the structure and performance of a fast DC Analyzer built at EE Department, IIT Bombay specifically for solving large circuits consisting of positive resistors, voltage sources, current sources and diodes. Using the simulator, we have analyzed circuits composed of diodes, positive resistors, current and voltage sources of size upto 700,000 nodes and 1.2 million edges on a 3.0 GHz, 1 GB RAM, PIV processor in at most 1.2 Hrs. We also report a comparative study of the performance of our DC analyzer with that of fastest commercial simulator.
Strategy for Displaying the Recognition Result in Interactive Vision
Authors: Yasushi Makihara, Jun Miura, Yoshiaki Shirai, Nobutaka Shimada
Venue: Proceedings of the 2005 International Conference on Cyberworlds (2005)

This paper describes a choice strategy to ease user's burdens for an interactive object recognition system when the system obtains multiple object candidates as a recognition result. First, we propose several methods to display the recognition result so as to make recognition of the candidates easy and hierarchical methods to reduce candidates per choice. We verify their effectiveness by subjective tests. Next, we propose a strategy to minimize time spent for choices. We divide the time into that for displayed candidates and that for speech dialog, and formulate each time to evaluate the strategy quantitatively. Last, we compare the strategy based on choice time with a subjective strategy.
Learning discontinuities with products-of-sigmoids for switching between local models
Authors: Marc Toussaint, Sethu Vijayakumar
Venue: Proceedings of the 22nd international conference on Machine learning (2005)

Sensorimotor data from many interesting physical interactions comprises discontinuities. While existing locally weighted learning approaches aim at learning smooth functions, we propose a model that learns how to switch discontinuously between local models. The local responsibilities, usually represented by Gaussian kernels, are learned by a product of local sigmoidal classifiers that can represent complex shaped and sharply bounded regions. Local models are incrementally added. A locality prior constrains them to learn only local data---which is the key ingredient for incremental learning with local models.
Hidden Markov chain estimation and parameterisation via ICA-based feature-selection
Authors: David Windridge, Richard Bowden
Venue: Pattern Analysis Applications (2005)

We set out a methodology for the automated generation of hidden Markov models (HMMs) of observed feature-space transitions in a noisy experimental environment that is maximally generalising under the assumed experimental constraints. Specifically, we provide an ICA-based feature-selection technique for determining the number, and the transition sequence of the underlying hidden states, along with the observed-state emission characteristics when the specified noise model assumptions are fulfilled. In retaining correlation information between features, the method is potentially more general than the commonly employed Gaussian mixture model HMM parameterisation methods, to which we demonstrate that our method reduces when an arbitrary separation of features, or an experimentally-limited feature-space is imposed. A practical demonstration of the application of this method to automated sign-language classification is given, for which we demonstrate that a performance improvement of the order of 40% over naive Markovian modelling of the observed transitions is possible.
Discretionary Caching for I/O on Clusters
Authors: Murali Vilayannur, Anand Sivasubramaniam, Mahmut Kandemir, Rajeev Thakur, Robert Ross
Venue: Cluster Computing (2006)

I/O bottlenecks are already a problem in many large-scale applications that manipulate huge datasets. This problem is expected to get worse as applications get larger, and the I/O subsystem performance lags behind processor and memory speed improvements. At the same time, off-the-shelf clusters of workstations are becoming a popular platform for demanding applications due to their cost-effectiveness and widespread deployment. Caching I/O blocks is one effective way of alleviating disk latencies, and there can be multiple levels of caching on a cluster of workstations.Previous studies have shown the benefits of caching--whether it be local to a particular node, or a shared global cache across the cluster--for certain applications. However, we show that while caching is useful in some situations, it can hurt performance if we are not careful about what to cache and when to bypass the cache. This paper presents compilation techniques and runtime support to address this problem. These techniques are implemented and evaluated on an experimental Linux/Pentium cluster running a parallel file system. Our results using a diverse set of applications (scientific and commercial) demonstrate the benefits of a discretionary approach to caching for I/O subsystems on clusters, providing as much as 48% savings in overall execution time over indiscriminately caching everything in some applications.
Making Sequential Consistency Practical in Titanium
Authors: Amir Kamil, Jimmy Su, Katherine Yelick
Venue: Proceedings of the 2005 ACM/IEEE conference on Supercomputing (2005)

The memory consistency model in shared memory parallel programming controls the order in which memory operations performed by one thread may be observed by another. The most natural model for programmers is to have memory accesses appear to take effect in the order specified in the original program. Language designers have been reluctant to use this strong semantics, called sequential consistency, due to concerns over the performance of memory fence instructions and related mechanisms that guarantee order. In this paper, we provide evidence for the practicality of sequential consistency by showing that advanced compiler analysis techniques are sufficient to eliminate the need for most memory fences and enable high-level optimizations. Our analyses eliminated over 97% of the memory fences that were needed by a na¨ýve implementation, accounting for 87 to 100% of the dynamically encountered fences in all but one benchmark. The impact of the memory model and analysis on runtime performance depends on the quality of the optimizations: more aggressive optimizations are likely to be invalidated by a strong memory consistency semantics. We consider two specific optimizations pipelining of bulk memory copies and communication aggregation and scheduling for irregular accesses and show that our most aggressive analysis is able to obtain the same performance as the relaxed model when applied to two linear algebra kernels. While additional work on parallel optimizations and analyses is needed, we believe these results provide important evidence on the viability of using a simple memory consistency model without sacrificing performance.
Performance Evaluation of Hybrid Genetic Algorithm for Assembly Line Scheduling
Authors: Song Hui
Venue: Proceedings of the 17th IEEE International Conference on Tools with Artificial Intelligence (2005)

In this paper; we present a new approach to tackle scheduling problems in manufacturers' assembly line. Former solutions also provide resu..l..ts, yet they turn out to be ineffective or time-consuming. Our approach involves several new schemes in crossover and mutation, which reduce its processing time. In order to avoid premature convergences of the chromosomes, we choose a self-adaptive mutation rate and a Clone-Replacement approach. We then try an alternative called Derivative Tree Crossover. Finally, the paper examines this algorithm's efficiency, which outperforms the previous methods.
Routing in Ad-hoc Networks with MIMO Links
Authors: Karthikeyan Sundaresan, Raghupathy Sivakumar
Venue: Proceedings of the 13TH IEEE International Conference on Network Protocols (2005)

Smart antennas include a broad variety of antenna technologies ranging from the simple switched beams to the sophisticated digital adaptive arrays. While beam-forming antennas are good candidates for use in strong line of sight (LOS) environments, it is the multiple input multiple output (MIMO) technology that is best suited for multipath environments. In fact, the MIMO links exploit the multipath induced rich scattering to provide high spectral efficiencies. The focus of this work is to identify the various characteristics and tradeoffs of MIMO links that can be leveraged by routing layer protocols in rich multipath environments to improve their performance. To this end, we propose a routing protocol called MIR for ad-hoc networks with MIMO links, that leverages the various characteristics of MIMO links in its mechanisms to improve the network performance. We show the effectiveness of the proposed protocol by evaluating its performance through ns2 simulations for a variety of network conditions.
A new two-message authentication protocol for RFID sensor networks
Authors: Selma Boumerdassi, Papa Kane Diop, Éric Renault, Anne Wei
Venue: Proceedings of the 3rd international workshop on Middleware for pervasive and ad-hoc computing (2005)

Radio Frequency Identification (RFID) technology is a method to remotely store and retrieve data using a small microchip called the RFID tag. This makes identification, authentication of objects and people possible without any physical contact between a tag and its reader. First developed in 1940 by the British army, RFID have developed considerably thanks to the fast development of radio techniques during the past few years. As of today, RFID have been applied to a wide range of problems: supply chain management to replace barcode, access control in restricted areas such as laboratories and airports, asset tracking and locating medical staff or certain patients to ensure an efficient response in medical emergencies. As a result, billions of tags will be deployed within the next years. However, RFID development is threatened by privacy and security risks. The limited capabilities of RFID tags make privacy and security enforcement a special challenge. This article presents a new method to ensure a mutual authentication between tags and readers using only two messages and without the use of complex cryptography.
A computer generated bibliography
Authors: Allan Gottlieb, Joan Bodoff
Venue: ACM SIGSOC Bulletin (1975)

The dominant use of computers in the social and behavioral sciences is for numeric calculations. For example, the statistical packages, SPSS, etc., have enjoyed widespread use and econometric models have often been implemented on computers, e.g. MIT's TROLL project.
Price-based rate control in random access networks
Authors: Clement Yuen, Peter Marbach
Venue: IEEE/ACM Transactions on Networking (TON) (2005)

We study a price-based rate control mechanism for random access networks. The mechanism uses channel feedback information to control the aggregate packet arrival rate. For our analysis, we use the standard slotted Aloha model with an infinite set of nodes. We show that the resulting Markov chain is positive recurrent. In addition, we characterize the throughput and delay at the operating point of the system and show how the operating point can be set a priori by appropriately choosing the control parameters. We illustrate our results using numerical experiments.
Telepresence support for synchronous distance
Authors: Juliana Restrepo, Helmuth Trefftz
Venue: Proceedings of the ACM symposium on Virtual reality software and technology (2005)

This paper describes a telepresence application that combines bi-directional video, audio and a shared virtual environment as means to support synchronous distance education sessions.In order to validate the effectiveness of the tool, it was used in several courses at our University. Students were divided into an experimental group -- using the tool in a simulated distance learning environment -- and a control group -- receiving traditional face-to-face lectures --. The results show that the use of the telepresence application, hand in hand with an appropriate pedagogical framework, lead the students in the distance education sessions to reach at least the same levels of understanding, and sometimes even better, than those attained by students in the face-to-face sessions.We are offering the telepresence application to other education institutions in our country, with the hope that it will allow students in regions isolated by the war or by the lack of infrastructure to have access to better education, both at school and university levels.
An exploration of evolutionary change in an example of scientific software
Authors: Diane Frances Kelly
Venue:  (2004)

Scientific software is typically long lived and does not seem to decay, despite high complexity and a relative lack of textbook software engineering practices. The study of such software may provide useful guidance for the evolution of other kinds of software. There is a wealth of examples to study. Unfortunately, most lack historical documentation, so new techniques have to be found to do longitudinal evolutionary studies. This thesis develops a change identification technique based on examining changes in the central data structures of the software. This technique is used to examine change in a particular example of successful, long-lived scientific software. Change is classified and analysed using a new change model, which is based on the idea that drivers for change come from a set of knowledge domains and are filtered by factors present in the environment, including the software itself. The combination of change drivers and change filters successfully accounts for the distribution of changes as observed. The thesis then considers the response of the original software design to changes that happened over roughly a 20 year period. A set of metrics is used to quantify the impacts of the changes, and to search for patterns of stability among a base version and three later versions of the software. Surprisingly, given the very different forces at work on the four versions, some interesting patterns of stability emerge. Some of the results of the thesis challenge established practices, such as the relative importance of information hiding, or the need to do extra work to prevent decay.
Network control architectures in wireless communication and mobile computing: power control and quality of service issues
Authors: Nicholas Bambos
Venue:  (2005)

Network control is key for efficient wireless networking and mobile computing. This thesis formulates and investigates selected core models of wireless network control elements, advancing the state of the art in this admittedly very broad subject. In particular, joint control opportunities across multiple network layers are identified, modeled and analyzed, leading to the design of efficient control algorithms. Beginning with plain transmitter power control, novel integrated schemes are introduced and investigated, resolving the coexistence problem of QoS-protected streaming traffic and bursty delay-tolerant data traffic, sharing a common wireless channel. The problem of joint control of transmitter power and relay switching is formulated and studied for a two-hop wireless packet communication. The core issue is whether intermediate relay nodes should receive or transmit at each time slot and what power level transmitters should use to efficiently forward packet traffic. Data prefetching and caching over fluctuating wireless channels is then studied jointly with transmitter power control. The main issue is the trade-off between data access latency at the receiver and interference stress induced on the wireless channel by the transmission power. The introduced problem formulation couples receiver buffer control (application layer) with transmitter power control (MAC layer). The problem of joint terminal-to-base task migration (over the wireless channel) and terminal processor speed management is then formulated and studied for reduced energy drain on battery-limited devices. Terminal computation tasks can potentially be uploaded to a base station server, get executed there fast, and have the results downloaded back to the terminal. The risk is that the &lsquo;soft&rsquo; connectivity induced by the wireless channel (due to mobility, etc.) may increase the resulting delivery latency. The focus is on formulating simple&mdash;yet insightful&mdash;models that capture fundamental performance trade-offs and leverage powerful control and optimization methodologies for exploring the nature and structure of core optimal network controls. Based on the latter, appropriate approximations and justified heuristics are introduced for complexity reduction and design of efficient operational algorithms.
Video Broadcasting using Overlay Multicast
Authors: Dragan Milic, Marc Brogle, Torsten Braun
Venue: Proceedings of the Seventh IEEE International Symposium on Multimedia (2005)

Despite the availability of high bandwidth Internet access for end-users, video broadcasting over the Internet is not widely spread. Multicast communication decreases the network load by eliminating redundancy of the data transfer. However IP Multicast was never widely accepted by commercial Internet service providers (ISP). Existing solutions solving this problem, like MBONE tunneling, are not available for end-users accessing the Internet via xDSL or TV cable. Application Layer Multicast using peer-to-peer (P2P) overlay networks could solve the problem of sparse IP Multicast support in the Internet. A limitation of this approach is the lack of standardized interfaces for existing IP Multicast applications. We propose a solution, which bridges Application Layer Multicast and IP Multicast and uses a P2P (Overlay) Network to transport multicast data. Our solution - including a "proof-of-concept" prototypeenables video broadcasting over the Internet using existing IP Multicast applications without requiring additional service deployment.