A Calculus for “environment-aware” computation

We present a calculus for modelling “environment-aware” computations, that is computations that adapt their behaviour according to the capabilities of the environment. The calculus is an imperative, object-based language with extensible objects, equipped with a labelled transition semantics. A notion of bisimulation, lifting to computations a correspondence between the capabilities of different environments, is provided. Bisimulation can be used to prove that a program is “cross-environment”, i.e., it has the same behaviour when run in different environments.     

Visualizing “typical” and “exotic” Internet traffic data

The threat of cyber attacks motivates the need to monitor Internet traffic data for potentially abnormal behavior. Due to the enormous volumes of such data, statistical process monitoring tools, such as those traditionally used on data in the product manufacturing arena, are inadequate. “Exotic” data may indicate a potential attack; detecting such data requires a characterization of “typical” data. We devise some new graphical displays, including a “skyline plot,” that permit ready visual identification of unusual Internet traffic patterns in “streaming” data, and use appropriate statistical measures to help identify potential cyberattacks. These methods are illustrated on a moderate-sized data set (135,605 records) collected at George Mason University.     

Stochastic programming and scenario generation within a simulation framework: An information systems perspective

Stochastic programming brings together models of optimum resource allocation and models of randomness to create a robust decision-making framework. The models of randomness with their finite, discrete realisations are called scenario generators. In this paper, we investigate the role of such a tool within the context of a combined information and decision support system. We explain how two well-developed modelling paradigms, decision models and simulation models can be combined to create “business analytics” which is based on ex-ante decision and ex-post evaluation. We also examine how these models can be integrated with data marts of analytic organisational data and decision data. Recent developments in on-line analytical processing (OLAP) tools and multidimensional data viewing are taken into consideration. We finally introduce illustrative examples of optimisation, simulation models and results analysis to explain our multifaceted view of modelling. In this paper, our main objective is to explain to the information systems (IS) community how advanced models and their software realisations can be integrated with advanced IS and DSS tools.     

“Electric” Zip Tips™, Preliminary Results

Induction based fluidics (IBF), a new, simple patented approach for transporting liquids in the micro and the macro world, is discussed. Electric fields are shown to energize liquid/s in a container/s to execute an array of purposes. IBF is shown uniquely to energize N liquids in simple off the shelf devices, inductively. We discuss calibration and other issues, as we demonstrate how simple devices can dispense nanoliters and microliters with high precision and accuracy. Furthermore, we show preliminary single and eight channel data for the Zip Tip™ made by Millipore where the device transports liquids “electrically.” We briefly consider how such new devices, “electric” Zip Tips™, might automate desalting and the placement of digests for MALDI TOF analysis.     

Undergraduate students' use of information elicited during e-mail “tutorials”

This study considers those questions posed by students during e-mail “tutorials” to elicit information from “guest lecturers” and the use of that information by students in their essays. The “tutorials” were conducted for students in the U.K. by a “guest lecturer” in France. The “guest lecturer” was accredited as a tutor on the module for which the students were enrolled, and participated in the module by the provision of lecture notes prior to the e-mail tutorials. Data for the study, drawn from a comparative education assignment set for undergraduate students enrolled on the module, comprised surveys of students' perceived IT capabilities and attitudes towards IT, analyses of students' questions and analyses of students' essays. The findings of the study indicate (1) that tutees tend to pose questions to elicit information or clarification rather than to elicit the viewpoint or opinions of the “guest lecturer” and (2) that two-thirds of tutees' essays cited information elicited from the “guest lecturer”.     

Learning algorithm for multimodal optimization

We present a new evolutionary algorithm—“learning algorithm” for multimodal optimization. The scheme for reproducing a new generation is very simple. Control parameters, of the length of the list of historical best solutions and the “learning probability” of the current solutions being moved towards the current best solutions and towards the historical ones, are used to assign different search intensities to different parts of the feasible area and to direct the updating of the current solutions. Results of numerical tests on minimization of the 2D Schaffer function, the 2D Shubert function and the 10D Ackley function show that this algorithm is effective and efficient in finding multiple global solutions of multimodal optimization problems.     

A “mixed” small gain and passivity theorem in the frequency domain

We show that the negative feedback interconnection of two causal, stable, linear time-invariant systems, with a “mixed” small gain and passivity property, is guaranteed to be finite-gain stable. This “mixed” small gain and passivity property refers to the characteristic that, at a particular frequency, systems in the feedback interconnection are either both “input and output strictly passive”; or both have “gain less than one”; or are both “input and output strictly passive” and simultaneously both have “gain less than one”. The “mixed” small gain and passivity property is described mathematically using the notion of dissipativity of systems, and finite-gain stability of the interconnection is proven via a stability result for dissipative interconnected systems.     

A nexus of Cyber-Geography and Cyber-Psychology: Topos/“Notopia” and identity in hacking

This paper explores the Cyber-Psychological and Cyber-Geographic aspects of hacking and hacktivism. An examination of the literature related to hackers and hacking reveals a complex nexus of spatial (including cyber-spatial such as “Notopia”) and psychological aspects of hacking, from which emerges a central question of how humans perceive and manipulate their cyber-identities. Concealing (real and cyber) identities is typical in hacking. With our progressive acculturation with identity-less and place-less modes of existence, our cyber-identities through time may be studied from within John Locke’s criterion of “memory” and the spatial-geographical criterion of identity.     

Alias types for “environment-aware” computations

In previous work with Bono we introduced a calculus for modelling “environment-aware” computations, that is computations that adapt their behavior according to the capabilities of the environment. The calculus is an imperative, object-based language (with extensible objects and primitives for discriminating the presence or absence of attributes of objects) equipped with a small-step operational semantics.In this paper we define a type and effect system for the calculus. The typing judgements specify, via constraints, the shape of environments which guarantees the correct execution of expressions and the typing rules track the effect of expression evaluation on the environment. The type and effect system is sound w.r.t. the operational semantics of the language.     

“To be recorded” analysis in reverse-mode automatic differentiation

The automatic generation of adjoints of mathematical models that are implemented as computer programs is receiving increased attention in the scientific and engineering communities. Reverse-mode automatic differentiation is of particular interest for large-scale optimization problems. It allows the computation of gradients at a small constant multiple of the cost for evaluating the objective function itself, independent of the number of input parameters. Source-to-source transformation tools apply simple differentiation rules to generate adjoint codes based on the adjoint version of every statement. In order to guarantee correctness, certain values that are computed and overwritten in the original program must be made available in the adjoint program. For their determination we introduce a static data-flow analysis called “to be recorded” analysis. Possible overestimation of this set must be kept minimal to get efficient adjoint codes. This efficiency is essential for the applicability of source-to-source transformation tools to real-world applications.     

Tool Integration with Triple Graph Grammars - A Survey

Nowadays, typical software and system engineering projects in various industrial sectors (automotive, telecommunication, etc.) involve hundreds of developers using quite a number of different tools. Thus, the data of a project as a whole is distributed over these tools. Therefore, it is necessary to make the relationships of different tool data repositories visible and keep them consistent with each other. This still is a nightmare due to the lack of domain-specific adaptable tool and data integration solutions which support maintenance of traceability links, semi-automatic consistency checking as well as update propagation. Currently used solutions are usually hand-coded one-way transformations between pairs of tools. In this article we present a rule-based approach that allows for the declarative specification of data integration rules. It is based on the formalism of triple graph grammars and uses directed graphs to represent MOF-compliant (meta) models. As a result we give an answer to OMG's request for proposals for a MOF-compliant “queries, views, and transformation” (QVT) approach from the “model driven application development” (MDA) field.     

Fixed-lag demodulation of discrete noisy measurements of FM signals

This paper considers an application of some recent results of fixed-lag smoothing algorithms to the demodulation of discrete noisy measurements of FM signals. The problem is attacked by first modelling the communications system in terms of a finite dimensional nonlinear stochastic system and relating the resulting model to an estimation problem for which approximate solutions can be obtained. Performance results are presented, using the modified truncated second order filtering algorithm. The results illustrate that if delay is allowed in arriving at an “on-line” optimum estimate, significant improvement can be obtained by even a very moderate fixed-lag.     

“Tryin to make a dolla outa fifteen cent”: Teaching composition with the Internet at an HBCU

Drawing upon nearly a decade of experience, I describe the challenges and advantages of teaching composition with the Internet at Howard University; I also explore the implications for other historically Black colleges and universities (HBCUs). First, I discuss the digital divide that has made it so difficult for many HBCU faculty members and students to access the Internet for composition courses. Next, I describe how students and I succeeded in harnessing the Internet not only to practice high-level writing skills but to “do cultural work”: to establish online “safe houses” for African American English, to collaborate with White North Americans and Black South Africans, and to publish Afrocentric material on the Web. In closing, I identify the pedagogical strategies that turned the Internet into a productive tool for the students in my writing courses.     

Who benefits from virtuality?

For educational software to take advantage of contemporary views of learning, instructional designers need to employ design models that incorporate the variety of ideas that are based on constructivist frameworks for developing learning environments. These environments, if well designed, can support learner construction of knowledge, however, such frameworks are based upon arguments that learners should be placed in authentic environments that incorporate sophisticated representations of context through such constructs as “virtual worlds”. Within these environments the learner is supported by visual metaphors constructed to represent the information structure and how the “world” operates. This paper will discuss the framework employed in the development of several virtual solutions and the process by which they were constructed.     

Review of several stochastic speech unit models

Hidden Markov models are commonly used for speech unit modelling. This type of model is composed of a non-observable or “hidden” process, representing the temporal structure of the speech unit, and an observation process linking the hidden process with the acoustic parameters extracted from the speech signal.Different types of hidden processes (Markov chain, semi-Markov chain, “expanded-state” Markov chain) as well as different types of observation processes (discrete, continuous, semi-continuous—multiple processes) are reviewed, showing their relationships. The maximum likelihood estimation of two-stage stochastic process parameters is presented in an a posteriori probability formalism. An intepretation of the expectation-maximization algorithm is proposed and the practical learning algorithms for hidden Markov models and hidden semi-Markov models are compared in terms of computation structure, probabilistic justification and complexity.This presentation is illustrated by experiments on a multi-speaker 130 isolated word recognition system. The implementation techniques are detailed and the different combinations of state occupancy modelling techniques and observation modelling techniques are studied from a practical point of view.     

Information retrieval expert system “matchmaker”

This paper describes the information system used to search for a potential matrimonial partner. The search is based on comparison of the subject's record, which consists of his/her answers to about 400 items of a specially designed questionnaire, to the records of the potential partners. The basic principle of the system is representation of the set of candidates for the client with psychological warnings about potential “conflict zones” in relationships between client and candidate rather than a ranking of candidates based on hypothetical “psychological compatibility” indices.     

Computational modeling issues and methods for the “regulatory problem” in engineering – Solutions to the structural dynamics and static frame problems

Many of the problems addressed through engineering analysis include a set of regulatory (or other) probabilistic requirements that must be demonstrated with some degree of confidence through the analysis. Problems cast in this environment can pose new challenges for computational analyses in both model validation and model-based prediction. The “regulatory problems” given for the “Sandia challenge problems exercise”, while relatively simple, provide an opportunity to demonstrate methods that address these challenges. This paper describes and illustrates methods that can be useful in analysis of the regulatory problem. Specifically, we discuss:

(1) an approach for quantifying variability and uncertainty separately to assess the regulatory requirements and provide a statement of confidence; and

(2) a general validation metric to focus the validation process on a specific range of the predictive distribution (the predictions near the regulatory threshold).

These methods are illustrated using the challenge problems. Solutions are provided for both the static frame and structural dynamics problems.

“The Spotting Accelerator™”, Customizable Head Assembly For Advanced Microarraying

Microarraying technologies have emerged as key tools for determining genomic expression. The quality of gene arrays is reliant on spotting pins for production of uniform spots, which are consistent in volume, shape, size and alignment.Point Technologies, Inc., has developed an advanced spotting technology. Emphasis has been placed on producing the “perfect spots” customized to each microarraying application. Uniform surface texturing such as highly polished or matte finishes, and hydrophilic/hydrophobic zonal coating is produced using Point Technologies' proprietary micro-machining technology. Microfabrication also permits the production of advanced pin designs, and high density, high throughput print-head assemblies of 1536 pins and greater. Point Technologies specializes in the micro-electrochemical machining of spotting pins in any size, shape and configuration.Presented data will demonstrate spotting pin design solutions, such as: variety of tip dimensions, surface finishes, specialized coatings, and material options instrumental in producing the ideal spot size, shape and spot density during extended usage.     

CAD — State of the art and a tentative forecast

The most important contemporary phenomenon in the mechanical engineering applications of CAD is the very rapid proliferation of systems, even in small and medium companies, driven by market imperatives and attracted by vastly improved cost/performance indices. The systems have expanded “upwards” from drafting to the modelling and analysis areas and “downstream” to process planning and documentation.Outstanding trends for the future are the use of knowledge-engineering techniques for problem solving, of novel database structures for intergrating data-growth over the product cycle, and of distributed architectures for building cooperative systems.