ppxscal/embedding_network huggingface dataset:
Passive Localization: Large Size Sensor Network Localization Based on Environmental Events
Authors: YoungMin Kwon, Gul Agha
Venue: Proceedings of the 7th international conference on Information processing in sensor networks (2008)

We develop a localization algorithm based on global environmental events observed by a sensor network. Examples of such events include the sound of thunder, the shades of moving clouds, or the vibrations in seismic data. Because our localization method does not generate signals for distance measurements, it saves energy. In fact, the algorithm may use existing sensor recordings to determine the locations of nodes at which the recordings were taken. Moreover, the method does not accumulate errors, making it also effective for large and sparse sensor networks. The localization uses time synchronization; we provide an algorithm to compensate for clock synchronization errors. Versions for both two dimensional and three dimensional localization of the algorithm are presented. Simulation results suggest that the algorithm can provide a high degree of accuracy when many events are recorded.
Linking VDM and Z
Authors: Jim Woodcock, Leo Freitas
Venue: Proceedings of the 13th IEEE International Conference on on Engineering of Complex Computer Systems (2008)

The International Grand Challenge in Verified Software is benchmarking current verification technology by conducting a series of experiments, and one such experiment is to build a verified POSIX-compliant flash filestore. An objective of this experiment is to combine different formal methods, and this raises issues about the different logics used. One significant area of difference is in the treatment of undefined expressions, and we show how this difference can be overcome using a unifying theory. This then allows us to use a theorem prover for Z to verify theorems about a data type specified and refined in VDM.
Iris Segmentation and Verification
Authors: Jong-Gook Ko, Jang-Hee Yoo, Ki-Young Moon
Venue: Proceedings of the 2007 Frontiers in the Convergence of Bioscience and Information Technologies (2007)

Iris recognition includes eye imaging, iris localization and verification and so on. This paper proposes a novel method for iris localization based on mask template and an efficient iris verification that employs cumulative sum based grey change analysis. Experimental results show that proposed method can be used for human identification in efficient manner.
Equalising stamp and substrate deformations in solid parallel-plate UV-based nanoimprint lithography
Authors: Iris Bergmair, Michael Mühlberger, Markus Gusenbauer, Rainer Schöftner, Kurt Hingerl
Venue: Microelectronic Engineering (2008)

We deal with solid parallel-plate UV-based nanoimprint lithography (UV-NIL) using rigid quartz stamps and spin coated substrates. Achieving a conformal contact of stamp and substrate in a parallel-plate setup is challenging, since the solid stamp and the substrate usually are not perfectly flat. Finite element simulations and experimental results show that a correctly designed compliant layer underneath the substrate guarantees a conformal contact of stamp and substrate and therefore imprints of a high quality with a homogeneous and thin residual layer down to 10nm can be achieved.
Short Term Analysis of Long Term Patterns of Heart Rate Variability in Subjects under Mental Stress
Authors: Desok Kim, Yunhwan Seo, Sook-hyun Kim, Suntae Jung
Venue: Proceedings of the 2008 International Conference on BioMedical Engineering and Informatics - Volume 02 (2008)

Long term patterns of heart rate variability (HRV) features were decreased in subjects with higher self reporting stress scores. For mobile applications, short term analysis of HRV features may be ideal since conventional heartbeat recordings (3~5 min) might be inadequately long. In this study, short term analysis has been performed for heartbeat data obtained at five different time points from two subject groups (15 under high and 18 under low mental stress). The reliability of short term heartbeat data was demonstrated by detecting significant differences in long term patterns of HRV features between two groups. Fifteen to thirty second heartbeat measurements were long enough to produce reliable long term patterns of HRV features. Thus, short and intermittent recordings of heartbeats could be used to detect long term HRV patterns and offer a convenient method to monitor mental stress in mobile environments.
Push-Pull Interest Management for Virtual Worlds
Authors: Rob Minson, Georgios Theodoropoulos
Venue: Proceedings of the 2008 11th IEEE Symposium on Object Oriented Real-Time Distributed Computing (2008)

Several approaches for scalable interest management (IM) within real-time distributed virtual environments (DVEs) have been proposed based upon some division of the data-space in to disjoint volumes or cells. Any such approach, however, must implement some mechanism for propagating the query and update messages around the distributed system. The efficiency of this process can greatly effect the scalability of such systems. In this paper we evaluate an adaptive approach to this problem.
Numbers of edges in supermagic graphs
Authors: Svetlana Drajnová, Jaroslav Ivančo, Andrea Semaničová
Venue: Journal of Graph Theory (2006)

A graph is called supermagic if it admits a labelling of the edges by pairwise different consecutive integers such that the sum of the labels of the edges incident with a vertex is independent of the particular vertex. In the paper we establish some bounds for the number of edges in supermagic graphs. &copy; 2005 Wiley Periodicals, Inc. J Graph Theory 52: 15&ndash;26, 2006
AVSynthesis: blending light and sound with OpenGL and Csound5
Authors: Dave Phillips
Venue: Linux Journal (2008)

Make your own abstract experimental films with the combined powers of two of the finest audio and video environments for Linux.
Quantified Impacts of Guardband Reduction on Design Process Outcomes
Authors: Kwangok Jeong, Andrew B. Kahng, Kambiz Samadi
Venue: Proceedings of the 9th international symposium on Quality Electronic Design (2008)

The value of guardband reduction is a critical open issue for the semiconductor industry. For example, due to competitive pressure, foundries have started to incent the design of manufacturing-friendly ICs through reduced model guardbands when designers adopt layout restrictions. The industry also continuously weighs the economic viability of relaxing process variation limits in the technology roadmap. Our work gives the first-ever quantification of the impact of modeling guardband reduction on outcomes from the synthesis, place and route (SP&R) implementation flow. We assess the impact of model guardband reduction on various metrics of design cycle time and design quality, using open-source cores and production (specifically, ARM/TSMC) 90nm and 65nm technologies and libraries. Our experimental data clearly shows the potential design quality and turnaround time benefits of model guardband reduction. For example, we typically (i.e., on average) observe 13% standard-cell areareduction and 12% routed wirelength reduction as the consequence of a 40% reduction in library model guardband; 40% is the amount of guardband reduction reported by IBM for a variation-aware timing methodology. We also assess the impact of guardband reduction on design yield. Our results suggest that there is justification for the design, EDA and process communities to enable guardband reduction as an economic incentive for manufacturing-friendly design practices.
LAOF: A New Framework to Efficiently Process Business Objects on Resource Constrained Mobile Phones
Authors: Huaigu Wu, Josh Borts, Yi Zheng, Yuri Natchetoi
Venue: Proceedings of the The Ninth International Conference on Mobile Data Management (2008)

The increase in the number of mobile device users has led to an increased demand for mobile business applications. One of the main challenges in developing mobile business applications is to efficiently process business data in the resource constrained environment of mobile phones. Current approaches are seriously limited by the non-guaranteed quality of network connections or the restricted processing capabilities of mobile phones. We propose a Lightweight Asynchronous Online Framework (LAOF) that merges the benefits of both online and offline models. In our approach, business data is partially and lazily replicated to mobile phones. The mobile application executes read-only operations locally and tentatively simulates local responses to write operations before asynchronously executing on the remote server. The LAOF improves the traditional lazy replication approach by 1) efficiently compressing business data for mobile applications, 2) separating the consistency requirements for responses and business data, and 3) providing an approach that guarantees causal dependency for the asynchronous execution of write operations on the server side. In addition, we also demonstrate a sample application based on this approach and use it to evaluate the framework.
Apply GM(h,N) Model to Analyze the Influence Factor in Cervical Cancer Screening
Authors: Su-Or Chen, Chih-Cheng Huang, Mei-Li You, Chaang-Yung Kung
Venue: Proceedings of the 2007 Frontiers in the Convergence of Bioscience and Information Technologies (2007)

Statistical data from the Department of Health, Executive Yuan (the executive branch of the government of the Republic of China) reveals that the rate of cervical cancer is higher than that of any other form of cancers in women. Cervical cancer is currently the fifth COD (Cause of Death) out of all of women cancer mortality in Taiwan. Hence, committing resources for cervical cancer prevention and treatment has become top priority to improve upon the health care of Taiwanese women. This paper tries to analyze the major influence factors with respect to cervical cancer. These concern the differences in rate of screening; rate of abnormality; rate of firm diagnosis; and rate of cure; together with important factors of screened abnormality. Ours is the pre-study for establishing an Integrated Assessment Model for Promoting Firm Diagnosis Rate of Patients with Cervical Cancer. Initially, we based this on an evaluation model that considered five factors as our object of study: (1) age group, (2) educational background, (3) contraception condition, (4) menstruation, and (5). results of the morbidity diagnosis. Our approach deviates from the traditional method since we now use the multivariable Grey model GM(h,N) to analyze the whole data, and by this means we find the weighting for the first four of the aforementioned factors, to correspond with the fifth one (the results of the morbidity diagnosis). The data was too large to analyze with the standard computational toolbox, so we additionally developed a Matlab toolbox. Not only did we succeed to use it to obtain the rank influence factor for cervical cancer, but it can now be used to extend the applicability of the GM(h,N) model to other medical disciplines.
Image recognition via Bayesian likelihood analysis of wavelet coefficients
Authors: Ester Yen, I-Wen Mike Chu
Venue: Expert Systems with Applications: An International Journal (2008)

This study experiments with a Bayesian approach in recognition of images utilizing a joint-form likelihood of wavelet coefficients built from decomposition. Images of handwritten numerals are attacked via the Mallet decomposition algorithm with Daubechies wavelets to extract the feature vectors of coefficients. The model assumes the coefficient vectors by multivariate normal distributions and employs a Bayesian approach for classification based on the joint form of distributions. The results demonstrate marked improvement in recognition performance at the second level of decomposition.
Optimizing complex queries with multiple relation instances
Authors: Yu Cao, Gopal C. Das, Chee-Yong Chan, Kian-Lee Tan
Venue: Proceedings of the 2008 ACM SIGMOD international conference on Management of data (2008)

Today's query processing engines do not take advantage of the multiple occurrences of a relation in a query to improve performance. Instead, each instance is treated as a distinct relation and has its own independent table access method. In this paper, we present MAPLE, a Multi-instance-Aware PLan Evaluation engine that enables multiple instances of a relation to share one physical scan (called SharedScan) with limited buffer space. During execution, as SharedScan pulls a tuple for any instance, that tuple is also pushed to the buffers of other instances with matching predicates. To avoid buffer overflow, a novel interleaved execution strategy is proposed: whenever an instance's buffer becomes full, the execution is temporarily switched to a drainer (an ancestor blocking operator of the instance) to consume all the tuples in the buffer. Thus, the execution is interleaved between normal processing and drainers. We also propose a cost-based approach to generate a plan to maximize the shared scan benefit as well as to avoid interleaved execution deadlocks. MAPLE is light-weight and can be easily integrated into existing RDBMS executors. We have implemented MAPLE in PostgreSQL, and our experimental study on the TPC-DS benchmark shows significant reduction in execution time.
Preventing Memory Error Exploits with WIT
Authors: Periklis Akritidis, Cristian Cadar, Costin Raiciu, Manuel Costa, Miguel Castro
Venue: Proceedings of the 2008 IEEE Symposium on Security and Privacy (2008)

Attacks often exploit memory errors to gain control over the execution of vulnerable programs. These attacks remain a serious problem despite previous research on techniques to prevent them. We present Write Integrity Testing (WIT), a new technique that provides practical protection from these attacks. WIT uses points-to analysis at compile time to compute the control-flow graph and the set of objects that can be written by each instruction in the program. Then it generates code instrumented to prevent instructions from modifying objects that are not in the set computed by the static analysis, and to ensure that indirect control transfers are allowed by the control-flow graph. To improve coverage where the analysis is not precise enough, WIT inserts small guards between the original program objects. We describe an efficient implementation with optimizations to reduce space and time overhead. This implementation can be used in practice because it compiles C and C++ programs without modifications, it has high coverage with no false positives, and it has low overhead. WIT's average runtime overhead is only 7% across a set of CPU intensive benchmarks and it is negligible when IO is the bottleneck.
Using multi-directional high-resolution imagery from POLDER sensor to retrieve leaf area index
Authors: F. Gascon, J. P. Gastellu-Etchegorry, M. Leroy
Venue: International Journal of Remote Sensing (2007)

Multi-directional satellite optical imagery collected at high spatial resolution potentially allows improving the accuracy of biophysical variable retrieval. The improvements result from the inclusion of the directional anisotropy of the target, which provides additional information related to vegetation structural properties. The research presented here analyses airborne imagery and ground reference data in order to quantify the accuracy of the retrieval methods for LAI (leaf area index). Both variables are estimated through processing of airborne POLDER (POLarization and Directionality of Earth Reflectances) sensor images from an agricultural area. In a first step, the BRDF (Bi-directional Reflectance Distribution Function) of the surface is estimated using a simple parametric model, whose parameters where derived from fitting POLDER BRF (Bi-directional Reflectance Factor) measurements. LAI estimation was performed using two different approaches, both based on an artificial neural network designed to invert a 1D soil-vegetation radiative transfer model. The difference between the two methods is that one of them uses only the isotropic component of the BRDF parametric model and the other the full BRDF information, i.e. adding the anisotropic components. The algorithm using isotropic information shows a clear improvement when compared to semi-empirical approaches. Root mean square error between estimated and ground measured LAI values is 0.87. However, the method using the full BRDF information yielded poorer estimates, pointing out the difficulty of fully exploiting the multi-directional information. The performance decrease is partially explained by the incoherence between real and modelled BRDF measurements.
Sequence of Hashes Compression in Data De-duplication
Authors: Subashini Balachandran, Cornel Constantinescu
Venue: Proceedings of the Data Compression Conference (2008)

Data de-duplication is a simple compression method that became verypopular in storage archival and backup. It has the advantage ofdirect, random access to any piece ("chunk") of a file in one tablelookup; that's not the case with differential file compression, theother common storage archival method. The compression efficiency(chunk matching) of de-duplication improves for smaller chunk sizes,however the sequence of hashes replacing the de-duplicated object(file) increases significantly. We propose a simple scheme to shrinkthe list of hashes generated during de-duplication of an object.This shrinkage is orders of magnitude smaller than what a customarycompression algorithm (gzip) achieves and has a significant impacton overall de-duplication efficiency.
A query simulation system to illustrate database query execution
Authors: Brett Allenstein, Andrew Yost, Paul Wagner, Joline Morrison
Venue: Proceedings of the 39th SIGCSE technical symposium on Computer science education (2008)

The underlying processes that enable database query execution are fundamental to understanding database management systems. However, these processes are complex and can be difficult to explain and illustrate. To address this problem, we have developed a Java-based query simulation system that enables students to visualize the steps involved in processing DML queries. We performed a field experiment to evaluate the system, and the results suggest that the system improves student comprehension of the query execution process.
On choosing a dense subgraph
Authors: G. Kortsarz, D. Peleg
Venue: Proceedings of the 1993 IEEE 34th Annual Foundations of Computer Science (1993)

This paper concerns the problem of computing the densest k-vertex subgraph of a given graph, namely, the subgraph with the most edges, or with the highest edges-to-vertices ratio. A sequence of approximation algorithms is developed for the problem, with each step yielding a better ratio at the cost of a more complicated solution. The approximation ratio of our final algorithm is O/spl tilde/(n/sup 0.3885/). We also present a method for converting an approximation algorithm for an unweighted graph problem (from a specific class of maximization problems) into one for the corresponding weighted problem, and apply it to the densest subgraph problem.
An improved lower bound on approximation algorithms for the Closest Substring problem
Authors: Jianxin Wang, Jianer Chen, Min Huang
Venue: Information Processing Letters (2008)

The Closest Substring problem (the CSP problem) is a basic NP-hard problem in the study of computational biology. It is known that the problem has polynomial time approximation schemes. In this paper, we prove that unless the Exponential Time Hypothesis fails, the CSP problem has no polynomial time approximation schemes of running time f(1/@e)n^o^(^1^/^@e^) for any function f. This essentially excludes the possibility that the CSP problem has a practical polynomial time approximation scheme even for moderate values of the error bound @e. As a consequence, it is unlikely that the study of approximation schemes for the CSP problem in the literature would lead to practical approximation algorithms for the problem for small error bound @e.
Optimal parallel all-nearest-neighbors using the well-separated pair decomposition
Authors: P. B. Callahan
Venue: Proceedings of the 1993 IEEE 34th Annual Foundations of Computer Science (1993)

We present an optimal parallel algorithm to construct the well-separated pair decomposition of a point set P in R/sup d/. We show how this leads to a deterministic optimal O(log n) time parallel algorithm for finding the k nearest neighbors of each point in P, where k is a constant. We discuss several additional applications of the well-separated pair decomposition for which we can derive faster parallel algorithms.
Dual syntax for XML languages
Authors: Claus Brabrand, Anders Møller, Michael I. Schwartzbach
Venue: Information Systems (2008)

XML is successful as a machine processable data interchange format, but it is often too verbose for human use. For this reason, many XML languages permit an alternative more legible non-XML syntax. XSLT stylesheets are often used to convert from the XML syntax to the alternative syntax; however, such transformations are not reversible since no general tool exists to automatically parse the alternative syntax back into XML. We present XSugar, which makes it possible to manage dual syntax for XML languages. An XSugar specification is built around a context-free grammar that unifies the two syntaxes of a language. Given such a specification, the XSugar tool can translate from alternative syntax to XML and vice versa. Moreover, the tool statically checks that the transformations are reversible and that all XML documents generated from the alternative syntax are valid according to a given XML schema.
Mesh massage: A versatile mesh optimization framework
Authors: Tim Winkler, Kai Hormann, Craig Gotsman
Venue: The Visual Computer: International Journal of Computer Graphics (2008)

We present a general framework for post-processing and optimizing surface meshes with respect to various target criteria. On the one hand, the framework allows us to control the shapes of the mesh triangles by applying simple averaging operations; on the other hand we can control the Hausdorff distance to some reference geometry by minimizing a quadratic energy. Due to the simplicity of this setup, the framework is efficient and easy to implement, yet it also constitutes an effective and versatile tool with a variety of possible applications. In particular, we use it to reduce the texture distortion in animated mesh sequences, to improve the results of cross-parameterizations, and to minimize the distance between meshes and their remeshes.
Using error-correcting dependencies for collaborative filtering
Authors: Galina Bogdanova, Tsvetanka Georgieva
Venue: Data Knowledge Engineering (2008)

Collaborative filtering aims to automate the process of organizing and recommending information to users. This process consists of predicting the user rating of a given item based on other users' ratings. We propose a new algorithm for tackling this problem based on discovering the functional error-correcting dependencies in a dataset by using the fractal dimension. We experimentally evaluate our algorithm and compare it to some of the baseline schemes. The experimental results presented in this paper prove that our approach improves the accuracy and the performance of the filtering.