ppxscal/embedding_network huggingface dataset:
Compiler-guided next sub-bank prediction for reducing instruction cache leakage energy
Authors: Wei Zhang
Venue: Journal of Embedded Computing (2006)

With the scaling of technology, leakage energy reduction has become increasingly important, especially for cache memories. Recent studies in drowsy instruction cache show that the leakage energy of the instruction cache can be significantly reduced with little performance degradation by exploiting the instruction spatial locality at the cache sub-bank level [5]. To hide the performance penalty due to the sub-bank wake-up latency, a prediction buffer is used to predict and pre-activate the next sub-bank at runtime. However, consulting the prediction buffer at every cache access consumes non-trivial dynamical energy, which can compromise the overall energy savings substantially. This paper presents a more energy-efficient compiler-guided approach to capture the sub-bank transition behavior at link time and to pre-activate the instruction cache sub-bank at runtime based on the compiler-directed hints. We also propose a hybrid approach to exploit both the static and dynamic information for reducing the performance penalty further with little dynamic energy overhead. Our experiments reveal that the static approach is very successful in capturing the sub-bank transition behavior to reduce the performance penalty and it also reduces 38.2% more leakage energy than the hardware-based approach, taking the dynamic energy overhead into account. Moreover, our results show that the hybrid approach is the best strategy for the drowsy instruction cache to balance leakage energy reduction and performance.
A cluster-based resampling method for pseudo-relevance feedback
Authors: Kyung Soon Lee, W. Bruce Croft, James Allan
Venue: Proceedings of the 31st annual international ACM SIGIR conference on Research and development in information retrieval (2008)

Typical pseudo-relevance feedback methods assume the top-retrieved documents are relevant and use these pseudo-relevant documents to expand terms. The initial retrieval set can, however, contain a great deal of noise. In this paper, we present a cluster-based resampling method to select better pseudo-relevant documents based on the relevance model. The main idea is to use document clusters to find dominant documents for the initial retrieval set, and to repeatedly feed the documents to emphasize the core topics of a query. Experimental results on large-scale web TREC collections show significant improvements over the relevance model. For justification of the resampling approach, we examine relevance density of feedback documents. A higher relevance density will result in greater retrieval accuracy, ultimately approaching true relevance feedback. The resampling approach shows higher relevance density than the baseline relevance model on all collections, resulting in better retrieval accuracy in pseudo-relevance feedback. This result indicates that the proposed method is effective for pseudo-relevance feedback.
Exact 3-D solution for system with rectangular fins, part 2
Authors: Andris Buikis, Margarita Buike
Venue: Proceedings of the 12th WSEAS International Conference on Applied Mathematics (2007)

In this paper we construct exact analytical three-dimensional solution for the distribution of the temperature field in the wall with arrays of rectangular fins. We assume that the heat transfer process in the wall and the fin is stationary. This exact solution is obtained by the Green function method. It is obtained in the form of the system of 2nd kind Fredholm integral equations with the numbers of equations equal to the number of the fins.
Teaching students to develop thread-safe java classes
Authors: Alan D. Fekete
Venue: ACM SIGCSE Bulletin (2008)

Concurrent programming was once the preserve of experts writing systems internals; but recently the growing importance of application servers, and the excellent support in Java and C# for thread handling, has brought threads and locking as topics that every software developer might experience, and therefore every computer science graduate ought to know. In this paper we report on several years of experience teaching this material in the early years of the curriculum. We focus on one aspect of multi-threaded code, namely how to write sensible thread-safe classes. We identify the learning outcomes we aim to deliver, and we discuss the main pedagogic difficulties students find. We present some examples that can help students avoid common erroneous views.
A note on the power of threshold circuits
Authors: E. Allender
Venue: Proceedings of the 30th Annual Symposium on Foundations of Computer Science (1989)

The author presents a very simple proof of the fact that any language accepted by polynomial-size depth-k unbounded-fan-in circuits of AND and OR gates is accepted by depth-three threshold circuits of size n raised to the power O(log/sup k/n). The proof uses much of the intuition of S. Toda's result that the polynomial hierarchy is contained in P/sup Hash P/ (30th Ann. Symp. Foundations Comput. Sci., p.514-519, 1989).
Autism and digital learning environments: Processes of interaction and mediation
Authors: Liliana M. Passerino, Lucila M. Costi Santarosa
Venue: Computers Education (2008)

Using a socio-historical perspective to explain social interaction and taking advantage of information and communication technologies (ICTs) currently available for creating digital learning environments (DLEs), this paper seeks to redress the absence of empirical data concerning technology-aided social interaction between autistic individuals. In terms of social interaction, autism can be likened to the negative of a photograph and it is currently one of the most disturbing and challenging syndromes. This study puts forward another viewpoint on the processes of interaction and mediation established in digital environments. Based on a 3-year multi-case study, which observed groups of autistic individuals in DLE-aided interaction activities, it identifies relevant technological categories that have an important contribution to make in the areas involved (Psychology, Education and Computer Science) in the development of a digital learning environment that takes the results achieved into account.
Fundamental study: Global dynamics for non-autonomous reaction-diffusion neural networks with time-varying delays
Authors: Zhiguo Yang, Daoyi Xu
Venue: Theoretical Computer Science (2008)

In this paper, a class of non-autonomous reaction-diffusion neural networks with time-varying delays is considered. Novel methods to study the global dynamical behavior of these systems are proposed. Employing the properties of diffusion operator and the method of delayed inequalities analysis, we investigate global exponential stability, positive invariant sets and global attracting sets of the neural networks under consideration. Furthermore, conditions sufficient for the existence and uniqueness of periodic attractors for periodic neural networks are derived and the existence range of the attractors is estimated. Finally two examples are given to demonstrate the effectiveness of these results.
Multi-tenant databases for software as a service: schema-mapping techniques
Authors: Stefan Aulbach, Torsten Grust, Dean Jacobs, Alfons Kemper, Jan Rittinger
Venue: Proceedings of the 2008 ACM SIGMOD international conference on Management of data (2008)

In the implementation of hosted business services, multiple tenants are often consolidated into the same database to reduce total cost of ownership. Common practice is to map multiple single-tenant logical schemas in the application to one multi-tenant physical schema in the database. Such mappings are challenging to create because enterprise applications allow tenants to extend the base schema, e.g., for vertical industries or geographic regions. Assuming the workload stays within bounds, the fundamental limitation on scalability for this approach is the number of tables the database can handle. To get good consolidation, certain tables must be shared among tenants and certain tables must be mapped into fixed generic structures such as Universal and Pivot Tables, which can degrade performance. This paper describes a new schema-mapping technique for multi-tenancy called Chunk Folding, where the logical tables are vertically partitioned into chunks that are folded together into different physical multi-tenant tables and joined as needed. The database's "meta-data budget" is divided between application-specific conventional tables and a large fixed set of generic structures called Chunk Tables. Good performance is obtained by mapping the most heavily-utilized parts of the logical schemas into the conventional tables and the remaining parts into Chunk Tables that match their structure as closely as possible. We present the re sults of several experiments designed to measure the efficacy of Chunk Folding and describe the multi-tenant database testbed in which these experiments were performed.
Untangling triangulations through local explorations
Authors: Pankaj K. Agarwal, Bardia Sadri, Hai Yu
Venue: Proceedings of the twenty-fourth annual symposium on Computational geometry (2008)

The problem of maintaining a valid mesh (triangulation) within a certain domain that deforms over time arises in many applications. During a period for which the underlying mesh topology remains unchanged, the deformation moves vertices of the mesh and thus potentially turns a mesh invalid, or as we call it, tangled. We introduce the notion of locally removable regions, which are certain tangled regions in the mesh that allow for local removal and re-meshing. We present an algorithm that is able to quickly compute, through local explorations, a minimum locally removable region containing a "seed" tangled region in an invalid mesh. By re-meshing within this area, the "seed" tangled region can then be removed from the mesh without introducing any new tangled region. The algorithm is output-sensitive in the sense that it never explores outside the output region.
Information Analysis for Enabling Optimal Utilization of Service Delivery Channels in Indian Banks
Authors: Hemalatha Diwakar, Alka Vaidya
Venue: Proceedings of the Seventh IEEE/ACIS International Conference on Computer and Information Science (icis 2008) (2008)

Banks in India have in recent times made extensive capital investments in Centralized Banking transaction Solutions and Service Delivery Technologies (SDTs) such as Automated Teller Machines (ATMs). Such SDTs have been sparingly used mostly for cash withdrawals while the bulk of other transactions still continue to be branch centric. In order to selectively shift transactions to these SDTs, banks need to review existing branch transactions from a volume cost-benefit and timeliness perspective at a branch level (there is a wide variability in the nature of clientele and type of transactions at different branches). This calls for a through analysis of branch level customer transactions. We have carried out the above said analysis using ORACLE and ORACLE BI on a sample branch data of an Indian Bank and the results strongly indicate that a sizable set of transactions can definitely be shifted to SDTs.
Layout-aware scan chain reorder for launch-off-shift transition test coverage
Authors: Sying-Jyan Wang, Kuo-Lin Peng, Kuang-Cyun Hsiao, Katherine Shu-Min Li
Venue: ACM Transactions on Design Automation of Electronic Systems (TODAES) (2008)

Launch-off-shift (LOS) is a popular delay test technique for scan-based designs. However, it is usually not possible to achieve good delay fault coverage in LOS test due to conflicts in test vectors. In this article, we propose a layout-based scan chain ordering method to improve fault coverage for LOS test with limited routing overhead. A fast and effective algorithm is used to eliminate conflicts in test vectors while at the same time restrict the extra scan chain routing. This approach provides many advantages. (1) The proposed method can improve delay fault coverage for LOS test. (2) With layout information taken into account, the routing penalty is limited, and thus the impact on circuit performance will not be significant. Experimental results show that the proposed LOS test method achieves about the same level of delay fault coverage as enhanced scan does, while the average scan chain wire length is about 2.2 times of the shortest scan chain.
A bijective proof of Jackson's formula for the number of factorizations of a cycle
Authors: Gilles Schaeffer, Ekaterina Vassilieva
Venue: Journal of Combinatorial Theory Series A (2008)

Factorizations of the cyclic permutation (12...N) into two permutations with respectively n and m cycles, or, equivalently, unicellular bicolored maps with N edges and n white and m black vertices, have been enumerated independantly by Jackson and Adrianov using evaluations of characters of the symmetric group. In this paper we present a bijection between unicellular partitioned bicolored maps and couples made of an ordered bicolored tree and a partial permutation, that allows for a combinatorial derivation of these results. Our work is closely related to a recent construction of Goulden and Nica for the celebrated Harer-Zagier formula, and indeed we provide a unified presentation of both bijections in terms of Eulerian tours in graphs.
Interactive visualization of uncertain spatial and spatio-temporal data under different scenarios: an air quality example
Authors: Edzer J. Pebesma, Kor de Jong, David Briggs
Venue: International Journal of Geographical Information Science (2007)

This paper introduces a method for visually exploring spatio-temporal data or predictions that come as probability density functions, e.g. output of statistical models or Monte Carlo simulations, under different scenarios. For a given moment in time, we can explore the probability dimension by looking at maps with cumulative or exceedance probability while varying the attribute level that is exceeded, or by looking at maps with quantiles while varying the probability value. Scenario comparison is done by arranging the maps in a lattice with each panel reacting identically to legend modification, zooming, panning, or map querying. The method is illustrated by comparing different modelling scenarios for yearly NO2 levels in 2001 across the European Union.
Building a PC in Easy Steps, 2nd edition
Authors: Stuart Yarnold
Venue: In Easy Steps (2007)

Prebuilt computer systems are often a compromise between what manufacturers want to sell and what consumers want to buy. For those who are looking for something more than the standard PC, one solution is to build it from the ground up a solution that, with the help of this book, is surprisingly simple. Written in concise, jargon-free English, Building a PC in Easy Stepswalks the reader through every stage of building and setting up a computer: buying parts and avoiding sales scams; mastering and installing the CPU, memory, video, and other components; altering default settings in the BIOS for optimum performance; and installing and configuring device drivers. Graphics clearly illustrate every step in the process, and an invaluable troubleshooting chapter helps pinpoint any problems that may crop up. In the end, the reader has a computer system tailored to their exact requirements, built from components specifically chosen for reliability, price, and performance.
Polynomial time approximation algorithms for multi-constrained QoS routing
Authors: Guoliang Xue, Weiyi Zhang, Jian Tang, Krishnaiyan Thulasiraman
Venue: IEEE/ACM Transactions on Networking (TON) (2008)

We study the multi-constrained quality-ofservice (QoS) routing problem where one seeks to find a path from a source to a destination in the presence of K ≥ 2 additive end-to-end QoS constraints. This problem is NP-hard and is commonly modeled using a graph with n vertices and m edges with K additive QoS parameters associated with each edge. For the case of K = 2, the problem has been well studied, with several provably good polynomial time-approximation algorithms reported in the literature, which enforce one constraint while approximating the other. We first focus on an optimization version of the problem where we enforce the first constraint and approximate the other K - 1 constraints. We present an O(mn log log n + mn/ε) time (1 + ε) (K - 1) -approximation algorithm and an O(mn log log n + m(n/ε)K-1) time (1 + ε) -approximation algorithm, for any ε > 0. When K is reduced to 2, both algorithms produce an (1 + ε) -approximation with a time complexity better than that of the best-known algorithm designed for this special case. We then study the decision version of the problem and present an O(m(n/ε)K-1) time algorithm which either finds a feasible solution or confirms that there does not exist a source-destination path whose first weight is bounded by the first constraint and whose every other weight is bounded by (1 - ε) times the corresponding constraint. If there exists an H-hop source-destination path whose first weight is bounded by the first constraint and whose every other weight is bounded by (1 - ε) times the corresponding constraint, our algorithm finds a feasible path in O(m(H/ε)K-1 time. This algorithm improves previous best-known algorithms with O((m + n log n)n/ε) time for K = 2 and O(mn(n/ε)K-1) time for K ≥ 2.
Removing ocular movement artefacts by a joint smoothened subspace estimator
Authors: Ronald Phlypo, Paul Boon, Yves D'Asseler, Ignace Lemahieu
Venue: Computational Intelligence and Neuroscience (2007)

To cope with the severe masking of background cerebral activity in the electroencephalogram (EEG) by ocular movement artefacts, we present a method which combines lower-order, short-term and higher-order, long-term statistics. The joint smoothened subspace estimator (JSSE) calculates the joint information in both statistical models, subject to the constraint that the resulting estimated source should be sufficiently smooth in the time domain (i.e., has a large autocorrelation or self predictive power). It is shown that the JSSE is able to estimate a component from simulated data that is superior with respect to methodological artefact suppression to those of FastICA, SOBI, pSVD, or JADE/COM1 algorithms used for blind source separation (BSS). Interference and distortion suppression are of comparable order when compared with the above-mentioned methods. Results on patient data demonstrate that the method is able to suppress blinking and saccade artefacts in a fully automated way.
A dictionary implementation based on dynamic perfect hashing
Authors: Martin Dietzfelbinger, Martin Hühne, Christoph Weidling
Venue: Journal of Experimental Algorithmics (JEA) (2008)

We describe experimental results on an implementation of a dynamic dictionary. The basis of our implementation is &ldquo;dynamic perfect hashing&rdquo; as described by Dietzfelbinger et al. (SIAM J. Computing 23, 1994, pp. 738--761), an extension of the storage scheme proposed by Fredman et al. (J. ACM 31, 1984, pp. 538--544). At the top level, a hash function is used to partition the keys to be stored into several sets. On the second level, there is a perfect hash function for each of these sets. This technique guarantees O(1) worst-case time for lookup and expected O(1) amortized time for insertion and deletion, while only linear space is required. We study the practical performance of dynamic perfect hashing and describe improvements of the basic scheme. The focus is on the choice of the hash function (both for integer and string keys), on the efficiency of rehashing, on the handling of small buckets, and on the space requirements of the implementation.
A power efficient and simple scheme for dynamically biasing cascode amplifiers and telescopic op-amps
Authors: Jaime Ramírez-Angulo, Milind Sawant, Antonio Lopez-Martin, Ramon G. Carvajal
Venue: Integration, the VLSI Journal (2008)

A simple dynamic biasing scheme to extend the input/output range of cascode amplifiers is introduced. It requires minimum extra hardware and no additional power consumption. A dynamic biased telescopic op-amp is discussed as an application example. Experimental results of a fabricated test chip in 0.5@mm CMOS technology are presented that verify the proposed technique.
Free-form Sketch
Authors: Haixiong Wang, Lee Markosian
Venue: Proceedings of the 4th Eurographics workshop on Sketch-based interfaces and modeling (2007)

We describe a sketch-based system for modeling 3D shapes based on a new multi resolution shape representation we call a layered mesh. Like subdivision surfaces, layered meshes provide a multi resolution hierarchy of meshes. A key difference is that a layered mesh lets you edit the shape and structure of the mesh at any level of the hierarchy, through the notion of shape primitives organized in a dependency network. The simplest primitives are points and curves, which can be used to define several kinds of parametric surface. Surface scan be inflated or smoothly joined to produce a broad range of shapes. An important feature of the system is the ability to refine shapes and add detail by oversketching primitives, either directly or via the curves that define them. While our user interface is still in development, our initial results show the potential for this approach.
Peer-to-Peer Context Reasoning in Pervasive Computing Environments
Authors: Tao Gu, Hung Keng Pung, Daqing Zhang
Venue: Proceedings of the 2008 Sixth Annual IEEE International Conference on Pervasive Computing and Communications (2008)

In this paper, we propose a peer-to-peer approach to derive and obtain additional context data from low-level context data that may be spread over multiple domains in pervasive computing environments. In this system, peers are self-organized into a semantic peer-to-peer network as the underlying communication substrate. Context reasoning is done in a distributed fashion through logical reasoning according to a set of user-defined rules. Both pull and push services are supported in the system to enable message exchange during the reasoning process. We present our design concepts, and prove the effectiveness of our system through the prototype evaluation.
Building heterogeneous peer-to-peer networks: protocol and analysis
Authors: Kin-Wah Kwong, H. K. Tsang
Venue: IEEE/ACM Transactions on Networking (TON) (2008)

In this paper, we propose a simple protocol for building heterogeneous unstructured peer-to-peer (P2P) networks. The protocol consists of two parts--the joining process and the rebuilding process. The basic idea for the joining process is to use a random walk to assist new incoming peers in selecting their suitable neighbors in terms of capacity and connectivity to achieve load-balancing. The rebuilding process specifies how the nodes should react when they lose links. In particular, we examine two representative schemes, namely the probabilistic-rebuilding scheme and the adaptive-rebuilding scheme. Furthermore, we provide a detailed analysis to investigate our proposed protocol under any heterogenous P2P environment. We prove that the topology structure of the P2P network depends heavily on the node heterogeneity. The analytical results are validated by the simulations. Our framework provides a guideline to engineer and optimize a P2P network in different respects under a heterogeneous environment. The ultimate goal of this paper is to stimulate further research to explore the fundamental issues in heterogeneous P2P networks.