ppxscal/embedding_network huggingface dataset:
A Concrete Syntax for UML 2.1 Action Semantics Using +CAL
Authors: Isabelle Perseil, Laurent Pautet
Venue: Proceedings of the 13th IEEE International Conference on on Engineering of Complex Computer Systems (2008)

Since UML 1.4 (the Unified Modeling Language, version 1.4), executable UML relies on the Precise Action Semantics for UML. The role of the action semantics is to provide the specification of actions. The UML has actions and activities, but no standard concrete syntax for describing them. Therefore, an action language is required to map higherlevel constructs to the actions. This action language has to encompass both primitive actions and the control mechanisms provided by behaviors. In our paper, we present the advantages of adopting a more generic action language, in order to raise the level of abstraction. For the particular domaine of Distributed Real-time Embedded (DRE) Systems, we have identified a need for formal verifications that leads us to implement a generic action language with formal features
A topological lower bound for the circular chromatic number of Schrijver graphs
Authors: Frédéric Meunier
Venue: Journal of Graph Theory (2005)

In this paper, we prove that the Kneser graphs defined on a ground set of n elements, where n is even, have their circular chromatic numbers equal to their chromatic numbers. &copy; 2005 Wiley Periodicals, Inc. J Graph Theory 49: 257&ndash;261, 2005
On convergence criteria of generalized proximal point algorithms
Authors: Yonghong Yao, Muhammad Aslam Noor
Venue: Journal of Computational and Applied Mathematics (2008)

We analyze some generalized proximal point algorithms which include the previously known proximal point algorithms as special cases. Weak and strong convergence of the proposed proximal point algorithms are proved under some mild conditions.
Tractability properties of the weighted star discrepancy
Authors: Aicke Hinrichs, Friedrich Pillichshammer, Wolfgang Ch. Schmid
Venue: Journal of Complexity (2008)

Tractability properties of various notions of discrepancy have been intensively studied in the last decade. In this paper we consider the so-called weighted star discrepancy which was introduced by Sloan and Wozniakowski. We show that under a very mild condition on the weights one can obtain tractability with s-exponent zero (s is the dimension of the point set). In the case of product weights we give a condition such that the weighted star discrepancy is even strongly tractable. Furthermore, we give a lower bound for the weighted star discrepancy for a large class of weights. This bound shows that for such weights one cannot obtain strong tractability.
Analysis of a double avalanche region IMPATT diode for high frequency part of millimetric region
Authors: Alexander Zemliak, Santiago Cabrera
Venue: Proceedings of the 2nd WSEAS International Conference on Circuits, Systems, Signal and Telecommunications (2008)

The analysis and optimization of the n+pvnp+ avalanche diode structure that includes two avalanche regions have been realized on basis of the nonlinear model and special optimization procedure. The admittance characteristics of the DAR diode were analyzed in very wide frequency band from 30 up to 360 GHz and had been optimized for the third frequency band near the 300 GHz.
Practical memory leak detector based on parameterized procedural summaries
Authors: Yungbum Jung, Kwangkeun Yi
Venue: Proceedings of the 7th international symposium on Memory management (2008)

We present a static analyzer that detects memory leaks in C programs. It achieves relatively high accuracy at a relatively low cost on SPEC2000 benchmarks and several open-source software packages, demonstrating its practicality and competitive edge against other reported analyzers: for a set of benchmarks totaling 1,777 KLOCs, it found 332 bugs with 47 additional false positives (a 12.4% false-positive ratio), and the average analysis speed was 720 LOC/sec. We separately analyze each procedure's memory behavior into a summary that is used in analyzing its call sites. Each procedural summary is parameterized by the procedure's call context so that it can be instantiated at different call sites. What information to capture in each procedural summary has been carefully tuned so that the summary should not lose any common memory-leak-related behaviors in real-world C programs. Because each procedure is summarized by conventional fixpoint iteration over the abstract semantics (a la abstract interpretation), the analyzer naturally handles arbitrary call cycles from direct or indirect recursive calls.
Closed-form supervised dimensionality reduction with generalized linear models
Authors: Irina Rish, Genady Grabarnik, Guillermo Cecchi, Francisco Pereira, Geoffrey J. Gordon
Venue: Proceedings of the 25th international conference on Machine learning (2008)

We propose a family of supervised dimensionality reduction (SDR) algorithms that combine feature extraction (dimensionality reduction) with learning a predictive model in a unified optimization framework, using data- and class-appropriate generalized linear models (GLMs), and handling both classification and regression problems. Our approach uses simple closed-form update rules and is provably convergent. Promising empirical results are demonstrated on a variety of high-dimensional datasets.
A new study on optimal calculation of partial transmission ratios of two-step helical gearboxes
Authors: Vu Ngoc Pi
Venue: Proceedings of the 2nd WSEAS International Conference on Computer Engineering and Applications (2008)

This paper introduces a new study on the applications of optimization and computer techniques for optimal calculation of the partial ratios of two-step helical gearboxes for minimal reducer length. In the paper, basing on moment equilibrium condition of a mechanic system including two gear units and their regular resistance condition, a new way for determining the partial ratios of two-step helical gearboxes were suggested. By using regression analysis, explicit models for calculation of the partial ratios are given. These models allow calculating the ratios accurately and simply.
Learning from wrong and creative algorithm design
Authors: David Ginat
Venue: ACM SIGCSE Bulletin (2008)

We all are aware of the relevance of examining a task from diverse angles. We also are aware of the potential relevance of learning from one's mistakes. Yet computer science (CS) textbooks and teaching materials fall short in embedding these two notions. In this paper, we present an approach of elaborating divergent thinking in algorithm design, while capitalizing on erroneous solutions. Using a collected set of non-routine algorithmic tasks, we developed and applied a scheme of class activities, in which initial faulty solutions (due to novice tendencies) are carefully examined, and their falsifying inputs and characteristics are used for creative reasoning that yields fruitful outcomes. We present and illustrate our activities, refer to their cognitive aspects, and describe our experience with applying them in (an Introduction-to-Algorithms) class.
Generating vast varieties of realistic leaves with parametric 2Gmap L-systems
Authors: Alexandre Peyrat, Olivier Terraz, Stephane Merillou, Eric Galin
Venue: The Visual Computer: International Journal of Computer Graphics (2008)

Creating realistic plants and trees require the ability to generate thousands of leaves with different shapes and textures for different given species. This paper presents an original method to generate large atlases of leaves with many details from a single formal grammar. Leaves are described by a parameterized 2Gmap L-system that describes their evolution in shape and texture through out their entire life cycle. Our approach automatically synthesizes the deformations as well as the color and texture changes as the leaves age, as well as defects such as holes or cracks produced by insect attacks or accidents.
The profession of ITVoices of computing
Authors: Peter J. Denning
Venue: Communications of the ACM (2008)

The choir of engineers, mathematicians, and scientists who make up the bulk of our field better represents computing than the solo voice of the programmer.
Technical Section: Optimizing the management of continuous level of detail models on GPU
Authors: O. Ripollés, M. Chover
Venue: Computers and Graphics (2008)

In this paper we present a new continuous multiresolution framework which has been developed in view of the outstanding evolution of hardware. Our interest not only focuses on exploiting GPUs possibilities, but also on making the best possible use of the capabilities offered by new bus technologies. On the one hand, we store the geometry, based on triangle strips, in high-performance memory on the GPU, offering fast rendering time. On the other hand, we have designed our level-of-detail extraction algorithm in order to make the most of current PCI Express bus characteristics, by sending the minimum information in the most appropriate way while taking into account the appearance of degenerate triangles. The results section shows that our model improves the efficiency of previously existing solutions. Its easy integration and its short extraction time make it suitable for game engines and graphics libraries which often resort to discrete models when it comes to selecting a multiresolution technique.
NARMAX-model-based time series modeling and prediction: feedforward and recurrent fuzzy neural network approaches
Authors: Yang Gao, Meng Joo Er
Venue: Proceedings of the 2nd WSEAS International Conference on Electronics, Control and Signal Processing (2003)

The nonlinear autoregressive moving average with exogenous inputs (NARMAX) model provides a powerful representation for time series analysis, modeling and prediction due to its strength to accommodate the dynamic, complex and nonlinear nature of real time series applications. This paper focuses on the modeling and prediction of NARMAX-model-based time series using the fuzzy neural network (FNN) methodology with an extention of the model represention include feedforward and recurrent FNNs. This paper introduces and develops a efficient algorithm, namely generalized fuzzy neural network (G-FNN) learning algorithm, for model structure determination and parameter identification with the aim of producing improved predictive performance for NARMAX time series models. Experiments and comparisons demonstrate that the proposed G-FNN approaches can effectively learn complex temporal sequences in an adaptive way and outperform some well-known existing methods.
Reachability is harder for directed than for undirected finite graphs
Authors: M. Ajtai, R. Fagin
Venue: Proceedings of the 29th Annual Symposium on Foundations of Computer Science (1988)

It is shown that for directed graphs, reachability can not be expressed by an existential monadic second-order sentence. The proof makes use of Ehrenfeucht-Fraisse games, along with probabilistic. However, it is shown that for directed graphs with degree at most k, reachability is expressible by an existential monadic second-order sentence. One reason for the interest in the main result is that while there is considerable empirical evidence (in terms of the efficiency of algorithms that have been discovered) that reachability in directed graphs is 'harder' than reachability in undirected graphs, this is the first proof in a precise technical sense that this is so.
Eye Detection Algorithm on Facial Color Images
Authors: Jalal Aldin Nasiri, Sara Khanchi, Hamid Reza Pourreza
Venue: Proceedings of the 2008 Second Asia International Conference on Modelling & Simulation (AMS) (2008)

In many applications such as face detection/recognition a major phase would be eye detection. In addition, its wide use as a part of serious applications, made it an important task should be worked on. Using color characteristics is a useful way to detect eyes. We use special color space, YCbCr which its components give us worthwhile information about eyes. We make two maps according to its components and merge them to obtain a final map. Candidates are generated on this final map. We apply an extra phase on candidates to determine suitable eye pair. The extra phase consists of flexible thresholding and geometrical tests. Flexible thresholding makes generating candidates more carefully and geometrical tests allow proper candidates to be selected as eyes. Simulation results on CVL and Iranian Databases showed this phase improved the correct detection rate by about 12.4% and reach 98.5% success rate on the average.
On the Failure of Rank-Revealing QR Factorization Software -- A Case Study
Authors: Zlatko Drmač, Zvonimir Bujanović
Venue: ACM Transactions on Mathematical Software (TOMS) (2008)

This article reports an unexpected and rather erratic behavior of the LAPACK software implementation of the QR factorization with Businger-Golub column pivoting. It is shown that, due to finite precision arithmetic, the software implementation of the factorization can catastrophically fail to produce a properly structured triangular factor, thus leading to a potentially severe underestimate of a matrix's numerical rank. The 30-year old problem, dating back to LINPACK, has (undetectedly) badly affected many computational routines and software packages, as well as the study of rank-revealing QR factorizations. We combine computer experiments and numerical analysis to isolate, analyze, and fix the problem. Our modification of the current LAPACK xGEQP3 routine is already included in the LAPACK 3.1.0 release. The modified routine is numerically more robust and with a negligible overhead. We also provide a new, equally efficient, and provably numerically safe partial-column norm-updating strategy.
An ontology-based architecture for implementing semantic integration of supply chain management
Authors: Yan Ye, Dong Yang, Zhibin Jiang, Lixin Tong
Venue: International Journal of Computer Integrated Manufacturing (2008)

Efficient supply chain management (SCM) requires consistent exchange and sharing of information semantics, which is often hindered by semantic clashes among heterogeneous applications. This paper proposes an ontology-based architecture for addressing the problem of semantic integration. A supply chain ontology (SCO) is developed by using the skeletal method to capture concepts and relationships common to SCM. Moreover, it is formally defined in OWL DL, a web-based ontology language, to serve as an interlingua for an architecture enabling information integration of SCM. Syntactic transformation between XML Schema and OWL in the architecture is implemented by syntactic translators that are developed by using XSLT. Furthermore, a rule-based approach is presented to map semantically similar terminologies between SCO and application ontologies with the aim of enabling semantic interoperability among applications in supply chains. The mapping rules are represented by SWRL, a rule description language that is independent of the rule languages specific to inference engines. In addition, a case study of a printer supply chain is illustrated to demonstrate the proposed methodology. Finally, a prototype system is developed using the Java platform to implement the SCO-based approach to semantic integration of SCM.
A comparison between two robust techniques for segmentation of blood vessels
Authors: Roberto Rodríguez, Patricio J. Castillo, Valia Guerra, Juan Humberto Sossa Azuela, Ana G. Suáreza, Ebroul Izquierdo
Venue: Computers in Biology and Medicine (2008)

Image segmentation plays an important role in image analysis. According to several authors, segmentation terminates when the observer's goal is satisfied. For this reason, a unique method that can be applied to all possible cases does not yet exist. In this paper, we have carried out a comparison between two current segmentation techniques, namely the mean shift method, for which we propose a new algorithm, and the so-called spectral method. In this investigation the important information to be extracted from an image is the number of blood vessels (BV) present in the image. The results obtained by both strategies were compared with the results provided by manual segmentation. We have found that using the mean shift segmentation an error less than 20% for false positives (FP) and 0% for false negatives (FN) was observed, while for the spectral method more than 45% for FP and 0% for FN were obtained. We discuss the advantages and disadvantages of both methods.
A multi-swarm optimizer based fuzzy modeling approach for dynamic systems processing
Authors: Ben Niu, Yunlong Zhu, Xiaoxian He, Hai Shen
Venue: Neurocomputing (2008)

Inspired by the phenomenon of symbiosis in natural ecosystems a multi-swarm cooperative particle swarm optimizer (MCPSO) is proposed as a new fuzzy modeling strategy for identification and control of non-linear dynamical systems. In MCPSO, the population consists of one master swarm and several slave swarms. The slave swarms execute particle swarm optimization (PSO) or its variants independently to maintain the diversity of particles, while the particles in the master swarm enhance themselves based on their own knowledge and also the knowledge of the particles in the slave swarms. With four benchmark functions, MCPSO is proved to have better performance than PSO and its variants. MCPSO is then used to automatically design the fuzzy identifier and fuzzy controller for non-linear dynamical systems. The proposed algorithm (MCPSO) is shown to outperform PSO and some other methods in identifying and controlling dynamical systems.
HMTT: a platform independent full-system memory trace monitoring system
Authors: Yungang Bao, Mingyu Chen, Yuan Ruan, Li Liu, Jianping Fan, Qingbo Yuan, Bo Song, Jianwei Xu
Venue: ACM SIGMETRICS Performance Evaluation Review (2008)

Memory trace analysis is an important technology for architecture research, system software (i.e., OS, compiler) optimization, and application performance improvements. Many approaches have been used to track memory trace, such as simulation, binary instrumentation and hardware snooping. However, they usually have limitations of time, accuracy and capacity. In this paper we propose a platform independent memory trace monitoring system, which is able to track virtual memory reference trace of full systems (including OS, VMMs, libraries, and applications). The system adopts a DIMM-snooping mechanism that uses hardware boards plugged in DIMM slots to snoop. There are several advantages in this approach, such as fast, complete, undistorted, and portable. Three key techniques are proposed to address the system design challenges with this mechanism: (1) To keep up with memory speeds, the DDR protocol state machine is simplified, and large FIFOs are added between the state machine and the trace transmitting logic to handle burst memory accesses; (2) To reconstruct physical-tovirtual mapping and distinguish one process' address space from others, an OS kernel module, which collects page table information, and a synchronization mechanism, which synchronizes the page table information with the memory race, are developed; (3) To dump massive trace data, we employ a straightforward method to compress the trace and use Gigabit Ethernet and RAID to send and receive the compressed trace. We present our implementation of an initial monitoring system, named HMTT (Hyper Memory Trace Tracker). Using HMTT, we have observed that burst bandwidth utilization is much larger than average bandwidth utilization, by up to 5X in desktop applications. We have also confirmed that the stream memory accesses of many applications contribute even more than 40% of L2 Cache misses and OS virtual memory management may decrease stream accesses in view of memory controller (or L2 Cache), by up to 30.2%. Moreover, we have evaluated OS impact on memory performance in real systems. The evaluations and case studies show the feasibility and effectiveness of our proposed monitoring mechanism and techniques.
Writing systems software in a functional language: an experience report
Authors: Iavor S. Diatchki, Thomas Hallgren, Mark P. Jones, Rebekah Leslie, Andrew Tolmach
Venue: Proceedings of the 4th workshop on Programming languages and operating systems (2007)

Current practices for developing systems software usually rely on fairly low-level programming languages and tools. As an alternative, our group has been investigating the possibility of using a high-level functional language, Haskell, for kernel and device driver construction, with the hope that it will allow us to produce more reliable and secure software. In this paper, we describe our experience developing a prototype operating system, House, in which the kernel, device drivers, and even a simple GUI, are all written in Haskell. The House system demonstrates that it is indeed possible to construct systems software in a functional language. However, it also suggests some ideas for a new Haskell dialect with features that target specific needs in this domain, including strongly typed support for low-level data structures and facilities for explicit memory accounting.
Should You Adopt Open Source Software?
Authors: Kris Ven, Jan Verelst, Herwig Mannaert
Venue: IEEE Software (2008)

Organizations have increasingly adopted open source software (OSS) as an essential part of their IT infrastructure. However, several reports and articles contain contradicting claims on the advantages and disadvantages of using OSS. This article describes how decision makers can interpret these reports. The authors performed a case study involving 10 Belgian organizations to support their conclusions from a review of the professional and academic literature. This article can provide decision makers with more insight into whether, when, and how to adopt OSS.
Comparing evolutionary algorithms to the (1+1) -EA
Authors: P. A. Borisovsky, A. V. Eremeev
Venue: Theoretical Computer Science (2008)

In this paper, we study the conditions in which the random hill-climbing algorithm (1 + 1)-EA compares favorably to other evolutionary algorithms (EAs) in terms of fitness function distribution at a given iteration and with respect to the average optimization time. Our approach is applicable when the reproduction operator of an evolutionary algorithm is dominated by the mutation operator of the (1 + 1)-EA. In this case one can extend the lower bounds obtained for the expected optimization time of the (1 + 1)-EA to other EAs based on the dominated reproduction operator. This method is demonstrated on the sorting problem with HAM landscape and the exchange mutation operator. We consider several simple examples where the (1 + 1)-EA is the best possible search strategy in the class of the EAs.