ppxscal/embedding_network huggingface dataset:
On imputing continuous data when the eventual interest pertains to ordinalized outcomes via threshold concept
Authors: Hakan Demirtas
Venue: Computational Statistics Data Analysis (2008)

Multiple imputation under the multivariate normality assumption has often been considered a workable model-based approach in dealing with incomplete continuous data. A situation where the measurements are taken on a continuous scale with an eventual interest in ordinalized versions via threshold concept is commonly encountered in applied research, especially in medical and social sciences. In practice, researchers ordinarily impute missing values for continuous outcomes under a Gaussian imputation model, and then ordinalize them via pre-specified cutoff points. An alternate strategy is creating multiply imputed data sets after ordinalization under a log-linear imputation model that uses a saturated multinomial structure. In this work, the performances of the two imputation methods were examined on a fairly broad range of simulated incomplete data sets that exhibit varying distributional characteristics such as skewness and multimodality. Behavior of efficiency and accuracy measures was investigated to determine the degree to which the procedures work appositely. The conclusion drawn is that ordinalization before carrying out a log-linear imputation should be the preferred procedure except for a few special cases. It is recommended that researchers use the less common second strategy whenever the interest centers on ordinal quantities that are obtained through underlying continuous measurements. This postulate is probably due to the transformation of non-Gaussian features into better-behaving categorical trends in this particular missing-data environment. This premise preponderates the factual argument that continuous variables intrinsically convey more information, leading to a counter-intuitive, but potentially beneficial result for practitioners.
A 90nm 8×16 FPGA Enhancing Speed and Yield Utilizing Within-Die Variations
Authors: Y. Sugihara, M. Kotani, K. Katsuki, K. Kobayashi, H. Onodera
Venue: Proceedings of the 2007 Asia and South Pacific Design Automation Conference (2007)

We have fabricated an LUT-based FPGA device with functionalities measuring within-die variations in a 90nm process. Measured variations are used to configure each device to maximize the operating frequency by allocating critical paths in faster portions. Variations are measured using ring oscillators implemented as a configuration of the FPGA. Placement optimization using a simple model circuit reveals that performance of the circuit is enhanced by 4% in average, which is the same amount as the measured within-die variations. The yield is enhanced by 32% to the worst case.
Developing realistic capstone projects in conjunction with industry
Authors: Sandra Gorka, Jacob R. Miller, Brandon J. Howe
Venue: Proceedings of the 8th ACM SIGITE conference on Information technology education (2007)

The information technology (IT) industry has the expectation that graduates of IT programs should be productive from day one with little or no additional training. In order to provide graduates who can meet this expectation, experiential learning activities are essential for today's undergraduate student. Experiential learning activities are beneficial at all course levels; however, experiences that occur early in a program are limited by the students' lack of broad-based knowledge in the field and do not provide a capstone experience. While internships and cooperative experiences are perhaps the easiest way to provide such learning activities, they may not be practical for all students. This paper addresses the benefits of developing capstone projects in conjunction with industry and how the authors develop such projects.
On guidelines for safe route redistributions
Authors: Franck Le, Geoffrey G. Xie
Venue: Proceedings of the 2007 SIGCOMM workshop on Internet network management (2007)

Route redistribution (RR) is becoming a critical tool in enterprise network operations. Like BGP, RR is prone to configuration errors, which may result in severe instabilities such as permanent routing loops and oscillations. In response, router vendors have put forth a set of recommendations on how to configure RR. However, the proposed guidelines are mainly derived from anecdotal experience and based on a limited range of parameters. Having not been subjected to systematic validation, their general effectiveness for preventing routing instabilities is largely unknown. This paper shows that the vendor recommendations do not completely eliminate routing instabilities and have severe limitations in terms of domain backup. It then presents a set of new guidelines with provable properties assuring safety, robustness, reachability, and domain backup. Configurations based on these guidelines allow routing domains of a network to safely exchange information and back up each other, thus increasing the robustness of the network against failures.
Output analysis of multiclass fluid models with static priorities
Authors: Elena I. Tzenova, Ivo J. B. F. Adan, Vidyadhar G. Kulkarni
Venue: Performance Evaluation (2008)

We consider a stochastic fluid flow model with a single server and K infinite capacity buffers. The input to the k-th buffer is a Markovian on-off process that transmits fluid at a constant rate p"k while it is on and at rate 0 while it is off. The fluid is emptied from the buffers by a single server at a constant rate @m according to a static priority service discipline in which class 1 fluid has the highest and class K fluid has the lowest priority. The output process of class k is defined to be on if fluid of class k is leaving the buffer at a positive rate and off otherwise. In this paper we derive an exact method for computing the mean on-time and the mean off-time of the output process of class k. We illustrate the method with a numerical example.
Building secure products and solutions
Authors: Ashok K. Gupta, Uma Chandrashekhar, Suhasini V. Sabnis, Frank A. Bastry
Venue: Bell Labs Technical Journal (2007)

Many security vulnerabilities in current information technology (IT) solutions and products are the result of a piecemeal &ldquo;strap-on&rdquo; security approach. The inclusion of many security add-ons, such as firewalls, antivirus software, intrusion detection systems (IDSs), and intrusion prevention systems (IPSs), may imply that the security objectives were an afterthought, not adequately defined initially, or that the required security objectives were never met by the individual system components. In fact, a &ldquo;grounds-up&rdquo; approach to security, where each component is individually secure, in a defined network deployment scenario helps meet the need of minimal risk exposure. Security should not be bolted on&semi; rather, it should be the prime consideration from the beginning and throughout the entire lifecycle&mdash;from concept to deployment and ongoing operation for each product in the solution. Given the ever-increasing sophistication of attacks, developing and monitoring secure products have become increasingly difficult. Despite the wide-scale awareness of common security flaws in software products, e.g., buffer overflows, resource exhaustion, and structured query language (SQL) injection, the same flaws continue to exist in some of the current products. The objective of this paper is to introduce a technology-agnostic approach to integrating security into the product development lifecycle. The approach leverages the Bell Labs Security Framework, the foundation of the International Telecommunication Union, Telecommunication Standardization Sector (ITU-T) X.805 global standard. Building this framework into the product lifecycle supports the goal of realizing secure products. The security framework can be applied to any product domain to facilitate security requirements analysis and the development of usable tools such as checklists, guidelines, and security policies. The application of Bell Labs Security Framework concepts and its use in the development of secure products are illustrated using the example of a centrally managed firewall product. &copy; 2007 Alcatel-Lucent.
Low-Power, High-Performance Architecture of the PWRficient Processor Family
Authors: Tse-Yu Yeh
Venue: IEEE Micro (2007)

The dual-core PA6T-1682M system on chip (SoC) is the first design in the PWRficient family of high-performance, low-power processor designs that target server-class performance with low power consumption. The heart of the PA6T-1682M is the PA6T core, which implements the 64-bit IBM Power Architecture. The SoC implements extensive features that support embedded and mobile low-power applications.
Evolutionary Programming with Operator Adaptation
Authors: Yong Liu
Venue: Proceedings of the 7th IEEE International Conference on Computer and Information Technology (2007)

This paper investigated evolutionary programming with operator adaptation at both population level and individ- ual level. The fitness distributions were employed to update operators at population level while the immediate reward or punishment from the feedback of mutations was applied to change operators at individual level. Experimental re- sults had shown that long jump operators could actually have smaller average winning step sizes. Through observ- ing the evolution of step sizes and fitness distribution values for each mutation operator, it was discovered that small- stepping operator could become the only dominant opera- tor while other more capable operators with long jumps had only been applied at rather low probabilites.
Teaching object oriented programming computer languages: learning based on projects
Authors: G. M. Ferreira, M. Z. Nascimento, K. D. R. Assis, R. P. Ramos
Venue: Proceedings of the International Conference on Software Engineering Advances (2007)

This work proposes to describe a teaching approach for introductory laboratory course in object-oriented programming and its respective teacher's experience. The profile of the first classes of freshmen, with different career goals, enrolled in Interdisciplinary Bachelor of Science and Technology at Federal University of ABC is presented. Educational methodology adopted in the lab using tutorials and a project-based learning approach is also discussed. Furthermore, some statistics about assessment of a student class in response to the learning activities, and its respective analysis are shown. And finally their evaluation about this educational approach is presented.
On Autonomous Logic Nets of Threshold Elements
Authors: S. Yajima, T. Ibaraki, I. Kawano
Venue: IEEE Transactions on Computers (1968)

Abstract A model of autonomous logic nets composed of n threshold elements is presented and several properties of a single threshold element are generalized to this model. The number of these nets is shown to be 2kn³(½=k=l) for completely specified machines. The capacity of the net is defined and conjectured to be 2, similar to the case of a single threshold element. P and NPN classifications of the machines are proposed and applied to the enumeration of all periodic sequences of length 2n(n=4) realizable by this net. The state assignment problem of the net is also treated. The existence of transition diagrams which cannot be realized by this model for any state assignment, or of those that can be realized for any state assignment, is shown, and it turns out that almost all completely specified machines belong to the former class when n is sufficiently large. Considering the synthesis of a net, an application of learning procedure is also discussed and it is pointed out that only periodic sequences of length 2" can be learned automatically.
Using concept maps to navigate complex learning environments
Authors: Susan L. Miertschin, Cheryl L. Willis
Venue: Proceedings of the 8th ACM SIGITE conference on Information technology education (2007)

A concept map is a graphical representation of relationships among concepts. Willis and Miertschin suggested the use of technology-based concept mapping as an active learning strategy that can enhance learning and thinking skills, particularly among students native to a digital environment [16]. In addition, modern concept mapping software tools enable instructors and students to create visual navigation structures through complex knowledge domains. The authors find value in visual navigation structures for their relevance to organizing and simplifying learning environments and for their appeal to visual learners. This paper investigates different ways to develop digital interactive concept maps (CMaps) to help students navigate complex knowledge domains, such as the content of a course or a curriculum. CMaps can be used to present information in a nonsequential way or in several different ways, depending on the need. Interactivity enables students to easily locate digital information artifacts pertinent to a concept (media files, slide presentations, web pages, etc.) by clicking on links associated with a CMap node representing the course concept or category. A review of recent literature is provided, different software tools are compared, and the authors document their personal experience. This material is based upon work supported by the National Science Foundation under Grant No. 0511672.
How Big Can You Think? Challenges at the Frontier
Authors: Dimitri Kusnezov
Venue: Computing in Science and Engineering (2007)

The world is on the threshold of a remarkable era of computing, in which raw computational power is no longer the limiting factor. The author argues that today's approach to computational science requires revision. This is becoming critical as simulation exerts greater influence on high-consequence decisions with societal impact.
Simulation Based Verification of Energy Storage Architectures for Higher Class Tags supported by Energy Harvesting Devices
Authors: A. Janek, Ch. Trummer, Ch. Steger, R. Weiss, J. Preishuber-Pfluegl, M. Pistauer
Venue: Proceedings of the 10th Euromicro Conference on Digital System Design Architectures, Methods and Tools (2007)

Enhanced RFID tag technology especially in the UHF frequency range provides extended functionality like high operating range and sensing and monitoring capabilities. Such functionality requiring extended system structures including data acquisition units, real time clocks and active transmitters causes a high energy consumption of the tag and requires an on board energy store (battery). As a key parameter of the reliability of an RFID system is the lifetime, the energy budget of the higher class tag has to be as balanced as possible. This can be achieved by using energy harvesting devices as additional power supply. The PowerTag 1 project and thus this paper proposes special energy storage structures interfacing energy harvesting devices and dealing with their special requirements for the use with battery-driven higher class UHF RFID tags. Different implementation variants of such structures are compared by using accurate simulation models of the various parts of the system. The results of the simulations are compared to manufacturer given and guaranteed system performance parameters of a state-of-the-art higher class UHF RFID system.
Automatic Web Services Composition Using Combining HTN and CSP
Authors: Incheon Paik, Daisuke Maruyama
Venue: Proceedings of the 7th IEEE International Conference on Computer and Information Technology (2007)

Semantic Web services and their composition portend a future where the Web can behave more intelligently for solving general real-life problems. To solve such real-life problems requires a set of appropriate services to be composed via planning, scheduled, and then executed: those are logical services composition, physical composition, and execution. Web service composition is the most difficult aspect and is our focus. In this paper, we propose a framework combining logical composition (using HTN) and physical composition (using CSP) for automatic services composition. The framework covers the entire procedures to deal with a user's request, domain analysis of the request, task flow decision and CSP creation by the planner, and solving the CSP by a distributed CSP solver for intelligent Web service composition. Implementation of the framework and an evaluation of it in terms of various problem solving types are then explained. We also discuss the necessity and synergy effect of the combined HTN and CSP for a framework that automates Web service composition and execution. Keywords Web Services Composition, Logical Composition, Physical Composition, Planning, CSP
Molecular weight and processing effects on the dissolution properties of thin poly(methyl methacrylate) films
Authors: A. Kokkinis, E. S. Valamontes, D. Goustouridis, Th. Ganetsos, K. Beltsios, I. Raptis
Venue: Microelectronic Engineering (2008)

An experimental set-up based on multiwavelength interferometry, is applied in order to study in-situ the dissolution process of thin resist films. The interference function was the basis for a fitting algorithm, which analyses the experimental data and evaluates the progress of the resist thickness with time. The dissolution of various PMMA molecular weights (15K, 350K, 996K) and resist thicknesses (20-300nm), in various developers, consisting of mixtures of methyl iso butyl ketone (MIBK), iso propanol (IPA), H"2O at various relative concentrations, was studied. Surface dissolution inhibition was shown in unexposed resists with high molecular weights and increased thickness in the case of MIBK-IPA 1-1 and IPA-H"2O 7-3 developers. After that the whole dissolution process evolved at a steady rate. Dissolution of thick films proved to be unpredictable showing complex dissolution curves. Low molecular weight resists presented a smooth dissolution curve without dissolution inhibition. Samples exposed with small DUV doses, exhibited dissolution behavior similar to the unexposed cases, whereas high exposure doses, within the lithographically useful range, led to smooth dissolution behavior. In the case of MIBK-IPA 1-3 developer significant swelling was observed.
Fox-ga: A genetic algorithm for generating and analyzing battlefield courses of action
Authors: J. L. Schlabach, C. C. Hayes, D. E. Goldberg
Venue: Evolutionary Computation (1999)

This paper describes FOX-GA, a genetic algorithm (GA) that generates and evaluates plans in the complex domain of military maneuver planning. FOX-GA's contributions are to demonstrate an effective application of GA technology to a complex real world planning problem, and to provide an understanding of the properties needed in a GA solution to meet the challenges of decision support in complex domains. Previous obstacles to applying GA technology to maneuver planning include the lack of efficient algorithms for determining the fitn ess of plans. Detailed simulations would ideally be used to evaluate these plans, but most such simulations typically require several hours to assess a single plan. Since a GA needs to quickly generate and evaluate thousands of plans, these methods are too slow. To solve this problem we developed an efficient evaluator (wargamer) that uses course-grained representations of this problem domain to allow appropriate yet intelligent trade-offs between computational efficiency and accuracy. An additional challenge was that users needed a diverse set of significantly different plan options from which to choose. Typical GA's tend to develop a group of “best” solutions that may be very similar (or identical) to each other. This may not provide users with sufficient choice. We addressed this problem by adding a niching strategy to the selection mechanism to insure diversity in the solution set, providing users with a more satisfactory range of choices. FOX-GA's impact will be in providing decision support to time constrained and cognitively overloaded battlestaff to help them rapidly explore options, create plans, and better cope with the information demands of modern warfare.
Improving SystemC simulation through Petri net reductions
Authors: N. Savoiu
Venue: Proceedings of the 2nd ACM/IEEE International Conference on Formal Methods and Models for Co-Design (2005)

With the growing acceptance of SystemC in co-design environments there is a need to further improve the simulation performance of complex designs. Our previous work has shown that simulation performance can be improved by carefully restructuring such designs. As a well known formal model for concurrent systems with a good balance between their expressive power and the theoretical results available for correlating structural properties with behavior, free-choice Petri nets were an ideal candidate for formalizing our restructuring technique. To do so we show how SystemC code can be mapped onto such nets followed by how such a labeled net can be reduced in a semantics preserving way. The end result is a restructured design which, as our experiments show, has improved simulation performance over the original models.
TCP Behaviour with Changes in Access Link Bandwidth and Delay During Vertical Handoffs
Authors: Laila Daniel, Markku Kojo
Venue: Proceedings of the The 2007 International Conference on Next Generation Mobile Applications, Services and Technologies (2007)

In this paper we study TCP performance in the presence of vertical handoffs between access networks with widely varying link characteristics. TCP being an end-to-end protocol has performance problems as its behaviour depends on the end-to-end path characteristics which are likely to be affected by a vertical handoff. We carry out a systematic study of TCP behaviour and the consequent problems that arise in various handoff scenarios between networks with different bandwidth and delay characteristics. This study can serve as a basis to evaluate any modifications to the TCP algorithm to adapt to a vertical handoff.
Collective caching: application-aware client-side file caching
Authors: Wei-keng Liao, K. Coloma, A. Choudhary
Venue: Proceedings of the High Performance Distributed Computing, 2005. HPDC-14. Proceedings. 14th IEEE International Symposium (2005)

Parallel file subsystems in today's high-performance computers adopt many I/O optimization strategies that were designed for distributed systems. These strategies, for instance client-side file caching, treat each I/O request process independently, due to the consideration that clients are unlikely related with each other in a distributed environment. However, it is inadequate to apply such strategies directly in the high-performance computers where most of the I/O requests come from the processes that work on the same parallel applications. We believe that client-side caching could perform more effectively if the caching subsystem is aware of the process scope of an application and regards all the application processes as a single client. In this paper, we propose the idea of "collective caching" which coordinates the application processes to manage cache data and achieve cache coherence without involving the I/O servers. To demonstrate this idea, we implemented a collective caching subsystem at user space as a library, which can be incorporated into any message passing interface implementation to increase its portability. The performance evaluation is presented with three I/O benchmarks on an IBM SP using its native parallel file system, GPFS. Our results show significant performance enhancement obtained by collective caching over the traditional approaches.