ppxscal/embedding_network huggingface dataset:
Exploiting unused storage resources to enhance systems' energy efficiency, performance, and fault-tolerance
Authors: Kang G. Shin
Venue:  (2006)

The invention of better fabrication materials and processes in solid-state devices has led to unprecedented technological breakthroughs in computer hardware. Today's system software, however, often cannot take full advantage of the hardware's rapidly improving capabilities, thus resulting in idling resources, e.g., unoccupied memory and disk space. To make hardware operate more efficiently and to reduce the amount of idle resources, this thesis proposes several techniques that can harness such resources to the benefit of users. Although there are many different types of hardware resources, this thesis focuses on the reclamation of idle resources in the storage hierarchy. First, we implemented a pure software technique to reduce the power dissipation of main memory. By aggregating unmapped and unused memory pages and powering down unused memory ranks, a significant amount of energy can be saved with little or no performance degradation. Next, we explored several architectural-level solutions that can more aggressively reduce energy, but at the expense of performance.We also developed techniques to exploit unused disk capacity to improve disks' performance and energy-efficiency. These techniques are realized in our implementation of the Free Space File System (FS2). Unlike traditional file systems where extra disk space is not used, FS2 actively makes use of it to hold replicas of temporally-related data blocks that were poorly placed by the underlying file system. Using contiguous regions of free disk space to place related data blocks closer to one another enables in disk heads to work more efficiently.Free disk space may also be used to enhance the fault-tolerance of disks. The placement of replicas is shown to be critical to both the fault-tolerance and performance of file systems that make use of replicas. However, without a thorough understanding of how disks fail and how data become corrupted when failures occur, good data placement strategies are difficult to devise. We studied a large number of failed disks and analyzed their failure characteristics. This characterization study will help design more fault-tolerant file systems that can take advantage of today's large capacity hard drives.
Decoy Discrimination Using Contact Potentials Based on Delaunay Tessellation of Hydrated Proteins
Authors: Gregory M. Reck, Iosif I. Vaisman
Venue: Proceedings of the 4th International Symposium on Voronoi Diagrams in Science and Engineering (2007)

Three strategies are presented for developing a knowledge-based statistical contact potential from computationally hydrated proteins that may be useful in studies of protein folding and stability. The potentials employ a definition of nearest neighbor contact based on Delaunay tessellation that identifies quadruplets of neighboring residues. The potentials are derived from a large set of proteins with explicit waters of hydration to improve the representation of the protein environment. The decoy discrimination ability of the three potentials as well as an unhydrated potential are evaluated and compared using four sets of publicly available protein decoy structures. The results suggest that the potentials can be used to infer the compatibility of a sequence of residues with a specific protein structure.
A robust routing protocol for wireless mobile ad hoc networks
Authors: Q. Wang, W. C. Wong
Venue: Proceedings of the The 8th International Conference on Communication Systems - Volume 02 (2002)

We first explore route redundancy mechanisms as means to minimize route discovery latencies of MANET protocols. We propose a new scheme AODV-RR (Ad Hoc On-demand Distance Vector Protocol with Redundant Routes) with improved robustness. The presence of redundant routes allows provision of immediate alternative routes to salvage time-critical traffic flows upon link failures. hence increasing throughput and minimizing delay. Further improvements are obtained by adapting Route Expiry Timeout (RET) to mobility at the expense of slight increase in overhead.
On AR modulated harmonics: CRB and parameter estimation
Authors: M. Ghogho
Venue: Proceedings of the Acoustics, Speech, and Signal Processing, 1996. on Conference Proceedings., 1996 IEEE International Conference - Volume 05 (1996)

The problem of estimation of harmonics with randomly time-varying amplitude is addressed. We deduce closed forms of the Cramer-Rao bounds by modeling these fluctuations by a Gaussian or non-Gaussian AR process. For the frequency estimation, the paper compares a parametric approach based on the ARMA representation of the signal and a non-parametric approach based on filtered version of higher-order statistics. Convergence and asymptotic normality of the estimators are established.
On Preconditioned Iterative Methods for Burgers Equations
Authors: Zhong-Zhi Bai, Yu-Mei Huang, Michael K. Ng
Venue: SIAM Journal on Scientific Computing (2007)

We study the Newton method and a fixed-point method for solving the system of nonlinear equations arising from the Sinc-Galerkin discretization of the Burgers equations. In each step of the Newton method or the fixed-point method, a structured subsystem of linear equations is obtained and needs to be solved numerically. In this paper, preconditioning techniques are applied to solve such linear subsystems. The bounds for eigenvalues of the preconditioned matrices are derived and numerical examples are given to illustrate the effectiveness of the proposed methods. We also find that a combination of the Newton/fixed-point iteration with the preconditioned GMRES method is quite efficient for the Sinc-Galerkin discretization of the Burgers equations.
Dimensionality Reductions in &#x2113;2 that Preserve Volumes and Distance to Affine Spaces
Authors: Avner Magen
Venue: Discrete Computational Geometry (2007)

Let X be a subset of n points of the Euclidean space, and let 0 < &#x03b5; < 1. A classical result of Johnson and Lindenstrauss [JL] states that there is a projection of X onto a subspace of dimension O(&#x03b5;-2 log n) with distortion &#x2264; 1+ &#x03b5;. We show a natural extension of the above result to a stronger preservation of the geometry of finite spaces. By a k-fold increase of the number of dimensions used compared with [JL], a good preservation of volumes and of distances between points and affine spaces is achieved. Specifically, we show how to embed a subset of size n of the Euclidean space into a O(&#x03b5;-2 log n)-dimensional Euclidean space, so that no set of size s &#x2264; k changes its volume by more than (1 + &#x03b5;s-1. Moreover, distances of points from affine hulls of sets of at most k - 1 points in the space do not change by more than a factor of 1 + &#x03b5;. A consequence of the above with k = 3 is that angles can be preserved using asymptotically the same number of dimensions as the one used in [JL]. Our method can be applied to many problems with high-dimensional nature such as Projective Clustering and Approximated Nearest Affine Neighbour Search. In particular, it shows a first polylogarithmic query time approximation algorithm to the latter. We also show a structural application that for volume respecting embedding in the sense introduced by Feige [F], the host space need not generally be of dimensionality greater than polylogarithmic in the size of the graph.
Image denoising via wavelet-domain spatially adaptive FIR Wiener filtering
Authors: H. Zhang
Venue: Proceedings of the Acoustics, Speech, and Signal Processing, 2000. on IEEE International Conference - Volume 04 (2000)

Wavelet domain denoising has recently attracted much attention, mostly in conjunction with the coefficient-wise wavelet shrinkage proposed by Donoho (see IEEE Trans. Inform. Theory, vol.41, no.3, p.613-27, May 1995). While shrinkage is asymptotically minimax-optimal, in many image processing applications a mean-squares solution is preferable. Most MMSE solutions that have appeared so far are based on an uncorrelated signal model in the wavelet domain, resulting in scalar (pixel-wise) operations. However, the coefficient clustering often observed in the wavelet domain indicates that coefficients are not independent. Especially in the case of undecimated discrete wavelet transform (UDWT), both the signal and noise components are non-white, thus motivating a more powerful model. This paper proposes a simple yet powerful extension to the pixel-wise MMSE wavelet denoising. Using an exponential decay model for autocorrelations, we present a parametric solution for FIR Wiener filtering in the wavelet domain. This solution takes into account the colored nature of signal and noise in UDWT, and is adaptively trained via a simple context model. The resulting Wiener filter offers impressive denoising performance at modest computational complexity.
Rediscovering learning: a survey of factors that affect student learning in engineering education
Authors: V. Hawks
Venue: Proceedings of the 26th Annual Frontiers in Education - Volume 01 (1996)

Innovations in technology, curricula and programs in engineering education are all directed toward the improvement of learning for engineering and technology students. In pursuit of these beneficial tools as a support to learning, the basics of learning, as the student sees them and as proven by experience and research, must not be forgotten. Extensive surveying has been done in the College of Engineering and Technology at Brigham Young University to identify factors that promote learning. Over 1000 students and alumni in the college were surveyed to identify the key facilitators of learning. Results show an interesting shift of some factors which are important to active students but not as important to alumni, while other factors maintain a strong position regardless of the student's level of or the alumnus's time in the field. Some of these factors include faculty knowledge and interest in teaching, grades and grading methods, hands-on experience and type of homework. A report is also given of a survey of students who had participated in classes that use a teaching method in which students are given full control over their grade. The intent of this method is to oblige students to accept responsibility for learning and to be more interested in understanding and applying the course material than in competing for a grade. The ACM Portal is published by the Association for Computing Machinery. Copyright © 2010 ACM, Inc. Terms of Usage Privacy Policy Code of Ethics Contact Us Useful downloads: Adobe Acrobat QuickTime Windows Media Player Real Player
AHIR: A Hardware Intermediate Representation for Hardware Generation from High-level Programs
Authors: Sameer D. Sahasrabuddhe, Hakim Raja, Kavi Arya, Madhav P. Desai
Venue: Proceedings of the 20th International Conference on VLSI Design held jointly with 6th International Conference: Embedded Systems (2007)

We present AHIR, an intermediate representation (IR), that acts as a transition layer between software compilation and hardware synthesis. Such a transition layer is intended to take advantage of optimisations available in the software compiler flow, and also to provide freedom to the low-level synthesiser, to explore options for application-specific implementations. Two operations become possible - reuse of computational resources across different modules in the design, and generation of an application-specific memory subsystem for faster data accesses. AHIR presents a decoupled view of the program, in terms of control flow, data flow and memory accesses. Each module in AHIR is a triplet consisting of a control-path, datapath and a symbolic association between the two. Memory is represented only by load-store operators, while the memory subsystem is separately designed by the implementor. In the program-to-hardware flow, a module in AHIR corresponds to a function in C. A complete program is a callgraph of functions, which is translated to a set of modules. The call-graph is restricted to be a DAG; recursion is not allowed. The representation is generated by a back-end in the software compiler, which runs after all source-level optimisations have been performed by relevant passes.
Advanced Experiments to Education Technical High School Students for Creation of Ubiquitous Networked Society
Authors: Kazuhisa Taniguchi, Ryuji Kaneda, Mika Kunishige, Aki Kojiri, Kaori Maeda, Reiji Aibara
Venue: Proceedings of the 2007 International Symposium on Applications and the Internet Workshops (2007)

The outcome of the current research on ubiquitous computing and networking affects the next generation. In other words, young generation is in charge of creating ubiquitous network world. In this paper, we describe our technical and educational trials to educate high school students, who will live in ubiquitous networked society. One topic is the experimental activity using IPv6 and remote control techniques. In the experiment, the high school students have developed the virtual environment of a ubiquitous networked society. Another topic is the development of a learning program to educate the students. Expanding the experiments, we are forwarding a plan to make a practical curriculum of the high school to educate the students who have required technology and ability in creation of ubiquitous networked world.
Managing Tcl's namespaces collaboratively
Authors: Don Libes
Venue: Proceedings of the 5th conference on Annual Tcl/Tk Workshop 1997 - Volume 5 (1997)

The NIST Identifier Collaboration Service (NICS) is a proposed service to encourage collaboration among researchers and developers when choosing identifiers, far in advance of when it might ordinarily occur. This would support and enhance standards development activities, and development and communications in a variety of fields from software development to system administration. Implementation of this system would provide immediate and significant time and cost-savings to many technology administrators, researchers, developers, and implementors world-wide. This paper describes the benefits of NICS to the Tcl community. This paper also briefly describes the implementation of NICS which is Tcl-based internally.
On Solving Block Toeplitz Systems Using a Block Schur Algorithm
Authors: Kyle Gallivan, Srikanth Thirumalai, Paul Van Dooren
Venue: Proceedings of the 1994 International Conference on Parallel Processing - Volume 03 (1994)

This paper presents a block Schur algorithm to obtain a factorization of a symmetric block Toeplitz matrix. We develop a version based on block hyperbolic Householder reflectors by adapting the representation schemes for block Householder reflectors to the hyperbolic case. If a singular principal submatrix is encountered during the factorization, the matrix is perturbed and an approximate factorization is obtained. This is then combined with iterative refinement to obtain the final solution.
PointguardTM: protecting pointers from buffer overflow vulnerabilities
Authors: Crispin Cowan, Steve Beattie, John Johansen, Perry Wagle
Venue: Proceedings of the 12th conference on USENIX Security Symposium - Volume 12 (2003)

Despite numerous security technologies crafted to resist buffer overflow vulnerabilities, buffer overflows continue to be the dominant form of software security vulnerability. This is because most buffer overflow defenses provide only partial coverage, and the attacks have adapted to exploit problems that are not well-defended, such as heap overflows. This paper presents PointGuard, a compiler technique to defend against most kinds of buffer overflows by encrypting pointers when stored in memory, and decrypting them only when loaded into CPU registers. We describe the PointGuard implementation, show that PointGuard's overhead is low when protecting real security-sensitive applications such as OpenSSL, and show that PointGuard is effective in defending against buffer overflow vulnerabilities that are not blocked by previous defenses.
Store Atomicity for Transactional Memory
Authors: Jan-Willem Maessen, Arvind
Venue: Electronic Notes in Theoretical Computer Science (ENTCS) (2007)

We extend the notion of Store Atomicity [Arvind and Jan-Willem Maessen. Memory model = instruction reordering + store atomicity. In ISCA '06: Proceedings of the 33rd annual International Symposium on Computer Architecture, 2006] to a system with atomic transactional memory. This gives a fine-grained graph-based framework for defining and reasoning about transactional memory consistency. The memory model is defined in terms of thread-local Instruction Reordering axioms and Store Atomicity, which describes inter-thread communication via memory. A memory model with Store Atomicity is serializable: there is a unique global interleaving of all operations which respects the reordering rules and serializes all the operations in a transaction together. We extend Store Atomicity to capture this ordering requirement by requiring dependencies which cross a transaction boundary to point in to the initiating instruction or out from the committing instruction. We sketch a weaker definition of transactional serialization which accounts for the ability to interleave transactional operations which touch disjoint memory. We give a procedure for enumerating the behaviors of a transactional program-noting that a safe enumeration procedure permits only one transaction to read from memory at a time. We show that more realistic models of transactional execution require speculative execution. We define the conditions under which speculation must be rolled back, and give criteria to identify which instructions must be rolled back in these cases.
How to shadow every byte of memory used by a program
Authors: Nicholas Nethercote, Julian Seward
Venue: Proceedings of the 3rd international conference on Virtual execution environments (2007)

Several existing dynamic binary analysis tools use shadowmemory-they shadow, in software, every byte of memory used by a program with another value that says something about it. Shadow memory is difficult to implement both efficiently and robustly. Nonetheless, existing shadow memory implementations have not been studied in detail. This is unfortunate, because shadow memory is powerful-for example, some of the existing tools that use it detect critical errors such as bad memory accesses, data races, and uses of uninitialised or untrusted data. In this paper we describe the implementation of shadow memory in Memcheck, a popular memory checker built with Valgrind, a dynamic binary instrumentation framework. This implementation has several novel features that make it efficient: carefully chosen data structures and operations result in a mean slow-down factor of only 22.2 and moderate memory usage. This may sound slow, but we show it is 8.9 times faster and 8.5 times smaller on average than a naive implementation, and shadow memory operations account for only about half of Memcheck's execution time. Equally importantly, unlike some tools, Memcheck's shadow memory implementation is robust: it is used on Linux by thousands of programmers on sizeable programs such as Mozilla and OpenOffice, and is suited to almost any memory configuration. This is the first detailed description of a robust shadow memory implementation, and the first detailed experimental evaluation of any shadow memory implementation. The ideas within are applicable to any shadow memory tool built with any instrumentation framework.
A study of how online learning resource are used
Authors: Mimi Recker, Sarah Giersch, Andrew Walker, Sam Halioris, Xin Mao, Bart Palmer
Venue: Proceedings of the 7th ACM/IEEE-CS joint conference on Digital libraries (2007)

This paper defines a model of teacher practice ("teaching as design"), and describes a professional development curriculum in which K-12 teachers design learning activities using resources and tools from education digital libraries. It then presents preliminary findings from an application of this model in which teachers' artifacts are analyzed to learn how online learning resources are used in situ. Initial results suggest that learning resources of a smaller granularity are more likely to be adapted or improvised upon in teacher-designed learning activities, which further supports teachers' becoming contributors of online resources and active participants in an education cyberinfrastructure.
Collecting and Sharing Location-based Content on Mobile Phones in a Zoo Visitor Experience
Authors: Kenton O'Hara, Tim Kindberg, Maxine Glancy, Luciana Baptista, Byju Sukumaran, Gil Kahana, Julie Rowbotham
Venue: Computer Supported Cooperative Work (2007)

The augmentation of visitor experiences with location-based technologies has been available for some time. Through in-depth studies of users during these experiences the field is building a rich picture of user behaviour in relation to certain location-based technologies. However, little work has explored the use of mobile camera phones and 2D barcodes on situated signs and their properties as a way of delivering such augmented visitor experiences. In this paper we present a study of people engaged in such a location-based experience at London zoo in which they use mobile camera phones to read 2D barcodes on signs at the animal enclosures in order to access related content. Through the fieldwork we highlight the social and collaborative aspects of the experience and how particular characteristics of the mobile phone and barcode technology shape these behaviours. The paper also highlights some of the non-instrumental aspects of the location-based experience, in particular in relation to the importance of collecting location-based content. We explore the social aspects of collecting as well as certain competitive elements it introduces into people's behaviour. This creates an interesting tension in that aspects of the application encourage cooperation and sharing among the visitors whereas others encourage competition. In the course of presenting the fieldwork, we explore this tension further.
Human Responsibility for Autonomous Agents
Authors: Ben Shneiderman
Venue: IEEE Intelligent Systems (2007)

Automated or autonomous systems can sometimes fail harmlessly, but they can also destroy data, compromise privacy, and consumeresources, such as bandwidth or server capacity. What's more troubling is that automated systems embedded in vital systems can causefinancial losses, destruction of property, and loss of life. Controlling these dangers will increase trust while enabling broader use ofthese systems with higher degrees of safety. Obvious threats stem from design errors and software bugs, but we can't overlook mistakenassumptions by designers, unanticipated actions by humans, and interference from other computerized systems. This article is part of aspecial issue on Interacting with Autonomy.
Design of the core modules for multimedia packet processing in a novel home gateway
Authors: Young-Choong Park, Chan-su Yoon, Kwang-mo Jung
Venue: Proceedings of the The 8th International Conference on Communication Systems - Volume 02 (2002)

Recently, there has been much effort in providing information technology into home appliances. Home network may link appliances, sensors, actuators, switches, controllers, and user interfaces to create novel applications and provide an infrastructure for multimedia distribution. However, there are various technologies of the home networking, which makes it difficult to give only one solution. Many developers and standardization organizations considers a home gateway as a good solution. In this paper, we propose a new architecture of a home gateway supporting various home network technologies such as IEEE1394, Bluetooth, LonWorks, wireless LAN, HPNA or implement Bluetooth technology using IP as a test model for our home gateway.