Development and applications of an interactive digital filter design program

We have implemented an interactive digital filter design program in the HP 1000 computer at the Department of Electrical Engineering of the University of Washington. This program allows users to design different types of filters interactively with both amplitude and phase responses displayed on graphic devices. The performance of each designed filter can be evaluated conveniently before the best one is chosen and implemented for any particular application. This program can design recursive filters, e.g. Butterworth, Chebyshev and elliptic, or nonrecursive filters with one out of six different windows, i.e. rectangular, triangular, Hann, Hamming, Blackman and Kaiser. The main outputs from this program are coefficients of a transfer function of an analog filter, a digital filter, or both. Therefore, the design of both analog and digital filters is facilitated by using this program. The program is very simple to use and does not require background in analog or digital filter principles in order to run it. The program is written in standard FORTRAN and is about 30 kbytes in size excluding the graphics display routines. Since it uses standard FORTRAN, it can be easily transported to minicomputer and microcomputer systems that have a FORTRAN compiler and minimal graphics capabilities. This program is available for distribution to interested institutions and laboratories.     

Eventor: an authoring system for interactive multimedia applications

Programming, testing, and maintaining interactive multimedia applications (IMAs) are still difficult and expensive, while substantial progress has been made to reduce the burden on authors. As IMAs get larger and more complex the difficulties will increase. To overcome the complexity of such IMAs, we argue that authoring systems should provide such facilities as (1) a traditional and intuitivedivide-and-conquer paradigm for solving large and complex problems in various fields, (2)formal specification of the behaviors of IMAs for checking the syntactic correctness of visual expressions or semantic anomalies, and (3)automatic aids like validation of temporal constraints and verification of visual expressions. In this paper, we investigate the properties of IMAs for recognizing the inherent interactivity and concurrency. We propose a specification method based on Milner'sCalculus of Communicating Systems (CCS), which is a well-known formal mechanism for specifying the concurrency in various distributed applications. We also design and implement an authoring system calledEventor (Event Editor), which is based on CCS and composed of three tools: a Temporal Synchronizer, a Spatial Synchronizer, and a User Interaction Builder. They focus on describing the temporal and spatial synchronizations and user interactions while they rely on existing tools in Intel's Digital Video Interactive (DVI) for supporting other functionalities. By editing a simple computer aided instruction (CAI) application, we illustrate that our specification mechanism is well-suited for handling the interactivity of multimedia applications, and Eventor is a simple, efficient, and powerful enough tool to handle practical applications. Especially the incremental refinement and the formal specification based on the CCS allow Eventor to be extended with formal verifications to cope with large and complex applications.     

Practice and experience with BASIS: An interactive programming system for introductory courses in informatics

The BASIS system is an interactive and conversational system, written in Pascal, to be used in the workshop of the introductory course in informatics. Its language is a subset of Pascal. Based on some years of experience with several versions of the system, we will discuss some implementational aspects.     

Paradigms for the design of interactive drama

The essential purpose of drama, whether it is theatre, film or television, is to evoke subjective experience in its audience. The advent of interactive digital television opens up many new possibilities for the structure and presentation of drama and the way in which people may engage with it. However, the design of interactive, computer-based environments requires theoretical and practical bases that are largely new to the dramatic arts. This paper describes research which is exploring the convergence of ideas and design models from a range of traditional sources including HCl, psychology, the performing arts and media production for this new media form. It starts by reevaluating two traditional dramatic paradigms, Stanislavski's Realism and Brecht's objectivity, and contrasts them with Boal's spect-actor paradigm in which audiences become direct participants in the drama. Although existing technology cannot enable a faithful computer based implementation of the spect-actor paradigm, the model may be approachable in various ways and thus provides a useful goal for designers of interactive drama. The realities of designing and producing interactive drama are illustrated with a practical example. The paper concludes with a discussion of the implications of the work for the design of interactive drama.     

The syntax of interactive command languages: A framework for design

Various qualities of simple command languages, such as ease of use and flexibility, are defined in terms of syntax. Certain design attributes—namely style, structure and level of abstraction—are described for command languages, and these attributes are shown to strongly influence the defined qualities. Commands are designed for three functions to show how the design trade-offs are made in light of the qualities and attributes discussed.     

A frame-based knowledge software tool for developing interactive robots

A knowledge-based software tool for developing interactive robot applications, called SPAK, has been developed. The “world” of interest is represented in a SPAK knowledge base by using a frame knowledge technique. This technique is chosen because it can represent the world meaningfully and naturally. Relationships among frames, which represent things in the world, and actions to be taken when certain things occur can be specified. In action, SPAK perceives changes in the environment, updates the knowledge base if needed, and generates output actions according to the knowledge contents. To support robotic applications, extensions to the conventional frame model are proposed. Various robotic applications can run cooperatively on top of SPAK. Each can easily make use of the knowledge available, and share its knowledge with others. A SPAK knowledge editor allows simple and intuitive development and modification of robot applications. To demonstrate these benefits, a prototype system and a sample robot application are developed. A multiagent technique is employed to combine various robotic components, both hardware and software, together. A sample dialogue manager for managing interactions with humans runs as an application on SPAK.     

An initial industrial evaluation of interactive search-based testing for embedded software

Search-based software testing promises the ability to generate and evaluate large numbers of test cases at minimal cost. From an industrial perspective, this could enable an increase in product quality without a matching increase in the time and effort required to do so.Search-based software testing, however, is a set of quite complex techniques and approaches that do not immediately translate into a process for use with most companies.For example, even if engineers receive the proper education and training in these new approaches, it can be hard to develop a general fitness function that covers all contingencies. Furthermore, in industrial practice, the knowledge and experience of domain specialists are often key for effective testing and thus for the overall quality of the final software system. But it is not clear how such domain expertise can be utilized in a search-based system.This paper presents an interactive search-based software testing (ISBST) system designed to operate in an industrial setting and with the explicit aim of requiring only limited expertise in software testing. It uses SBST to search for test cases for an industrial software module, while also allowing domain specialists to use their experience and intuition to interactively guide the search.In addition to presenting the system, this paper reports on an evaluation of the system in a company developing a framework for embedded software controllers. A sequence of workshops provided regular feedback and validation for the design and improvement of the ISBST system. Once developed, the ISBST system was evaluated by four electrical and system engineers from the company (the ‘domain specialists’ in this context) used the system to develop test cases for a commonly used controller module. As well as evaluating the utility of the ISBST system, the study generated interaction data that were used in subsequent laboratory experimentation to validate the underlying search-based algorithm in the presence of realistic, but repeatable, interactions.The results validate the importance that automated software testing tools in general, and search-based tools, in particular, can leverage input from domain specialists while generating tests. Furthermore, the evaluation highlighted benefits of using such an approach to explore areas that the current testing practices do not cover or cover insufficiently.     

Localized tensor-based solvers for interactive finite element applications using C++ and Java

This paper presents techniques for solving systems of equations arising in finite element applications using a localized, tensor-based approach. The approach is localized in that a major part of the solution responsibility is delegated to vector degree-of-freedom objects, rather than residing solely in a global solver working on a monolithic data structure. The approach is tensor-based in that the fundamental quantities used for computation are considered to be second-order tensors. The localized data structure strategy provides the benefits of an efficient sparse and symmetric storage scheme without requiring complex implementation code. The tensor-based aspect of the approach can bring substantial performance benefits by increasing the granularity at which solution algorithms deal with their data. Java and C++ implementations of interactive finite element programs are used to demonstrate performance that is competitive with other available solvers, especially in the case of problems for which interactive analysis is feasible on commonly available hardware.     

Q'Nial: A portable interpreter for the nested interactive array language,Nial

The Q'Nial interpreter combines ideas from APL and Lisp implementations to provide a rich programming environment that supports several paradigms of programming. The interpreter is structured to reflect the division of Nial semantics into levels corresponding to zero-, first-and second-order objects. The paper describes the design of the interpreter, discusses constraints imposed by the desire to achieve portability and comments on what has been learned in building an interpreter in this style.     

WebTOP: A 3D interactive system for teaching and learning optics

WebTOP is a three-dimensional, Web-based, interactive computer graphics system that helps instructors teach and students learn about waves and optics. Current subject areas include waves, geometrical optics, reflection and refraction, polarization, interference, diffraction, lasers, and scattering. Some of the topics covered are suited for introductory level physics students while others are suited for intermediate optics students. WebTOP is developed with a flexible interface to suit the various needs of instructors and students. Many of the features lend themselves to classroom use or self-guided study. WebTOP is implemented using VRML, Java, JavaScript, and VRML’s Java EAI.     

A unified theory for software production

The central problem of software engineering, namely an overall strategy for the successful production of large-scale software, has not yet been solved. Various techniques do exist for separate sections of the production process, but largely owing to the huge costs involved, it is virtually impossible to perform controlled experiments to test their validity, or to compare competing methodologies. One alternative way of deciding which techniques are to be preferred is to set up a science of software management, and to evaluate methodologies within its framework. This paper is a first step towards such a science. It notes similarities between certain techniques for structuring the programming group, the program modules, the testing process and the actual code itself. A theory is then deduced which enables programming managers to choose from among the wide selection of available techniques those which are applicable to the specific system to be written.     

A remote display QoE improvement scheme for interactive applications in low network bandwidth environment

Screen transmission is an essential part of Desktop as a Service (DaaS) which directly influence the quality of experience (QoE). In this paper, we propose a novel QoE improvement scheme that dynamically controls the quality setting of the image compression before the screen transmission to decrease response time of the system still maintaining the satisfactory image quality, hence improves the QoE in interactive applications in a band-limited environment. The proposed scheme first selects the best quality setting appropriate for current network bandwidth quota, then uses the remaining bandwidth to improve the quality setting of low motion regions without any adverse effect on response time. To enable the adaptive quality selection and image quality refinement, we propose a compressed image file size inference model and a block priority calculation method respectively. Particularly, we implement our QoE Improvement Scheme to work with screen content coding. Both quantitative measurements and users’ evaluations in the experiments show that our QoE improvement scheme improves QoS as well as QoE by utilizing the available network bandwidth efficiently.     

Graphical models for interactive POMDPs: representations and solutions

We develop new graphical representations for the problem of sequential decision making in partially observable multiagent environments, as formalized by interactive partially observable Markov decision processes (I-POMDPs). The graphical models called interactive influence diagrams (I-IDs) and their dynamic counterparts, interactive dynamic influence diagrams (I-DIDs), seek to explicitly model the structure that is often present in real-world problems by decomposing the situation into chance and decision variables, and the dependencies between the variables. I-DIDs generalize DIDs, which may be viewed as graphical representations of POMDPs, to multiagent settings in the same way that I-POMDPs generalize POMDPs. I-DIDs may be used to compute the policy of an agent given its belief as the agent acts and observes in a setting that is populated by other interacting agents. Using several examples, we show how I-IDs and I-DIDs may be applied and demonstrate their usefulness. We also show how the models may be solved using the standard algorithms that are applicable to DIDs. Solving I-DIDs exactly involves knowing the solutions of possible models of the other agents. The space of models grows exponentially with the number of time steps. We present a method of solving I-DIDs approximately by limiting the number of other agents’ candidate models at each time step to a constant. We do this by clustering models that are likely to be behaviorally equivalent and selecting a representative set from the clusters. We discuss the error bound of the approximation technique and demonstrate its empirical performance.     

GEOFILE: an interactive program in basic for creating and editing data files

GEOFILE is a versatile, interactive program in BASIC for the creation and editing of data files. These files consist of a two-dimensional array of numerical values, rows corresponding to different parameters, and columns to different samples. In addition to numerical values, the files also contain strings corresponding to sample numbers, sample labels, and parameter symbols. Rapid and successful file creation is assisted by the large number of error-traps in the program and comprehensive file editing is accomplished partly through a simple routine which uses an alphanumeric grid to identify data items. Files created and/or edited may be stored on disk for subsequent use in a variety of other programs such as graph plotting or statistical analysis.     

Accounting and billing software and user reactions: An interactive diagnostic audit trail

The selection of an accounting and billing software (ABS) system is a complicated process. The overall satisfaction derived from a system depends on many variables. This study analyzes the influence of ABS (predictor) variables on overall satisfaction. It confirms our hypotheses that ease of operation, computer reliability, and ease of programming are the major determinants of overall computer user satisfaction. These factors were used in the design of an ABS diagnostic system based on audit trails (DSAT).     

TrackGen: An interactive track generator for TORCS and Speed-Dreams

TrackGen is an online tool for the generation of tracks for two open-source 3D car racing games (TORCS and Speed Dreams). It integrates interactive evolution with procedural content generation and comprises two components: (i) a web frontend that maintains the database of all the evolved populations and manages the interaction with users (by collecting users evaluations and providing access to the evolved tracks) and (ii) an evolutionary/content-generation backend that runs both the evolutionary algorithm and generates the actual game content that is available through the web frontend. The first prototype of the tool was presented in July 2011 but advertised only to researchers; the first official version which generated tracks only for TORCS was released to the game community in September 2011; due to the many requests, we released a new version soon afterwards, in January 2012, with support for Speed Dreams (the fork of TORCS focused on visual realism and graphic quality) that has been online since then. From January 2012 until July 2014, TrackGen had more than 7600 unique visitors who visited the website around 11,500 times and viewed 85,500 pages; it was employed to evolve more than 8853 tracks, and it was used to download 12,218 tracks. Some of the tracks evolve by our system have been also included in the TORCS distribution.     

A comparison of meta-heuristic search for interactive software design

Advances in processing capacity, coupled with the desire to tackle problems where a human subjective judgment plays an important role in determining the value of a proposed solution, has led to a dramatic rise in the number of applications of Interactive Artificial Intelligence. Of particular note is the coupling of meta-heuristic search engines with user-provided evaluation and rating of solutions, usually in the form of Interactive Evolutionary Algorithms (IEAs). These have a well-documented history of successes, but arguably the preponderance of IEAs stems from this history, rather than as a conscious design choice of meta-heuristic based on the characteristics of the problem at hand. This paper sets out to examine the basis for that assumption, taking as a case study the domain of interactive software design. We consider a range of factors that should affect the design choice including ease of use, scalability, and of course, performance, i.e. that ability to generate good solutions within the limited number of evaluations available in interactive work before humans lose focus. We then evaluate three methods, namely greedy local search, an evolutionary algorithm and ant colony optimization (ACO), with a variety of representations for candidate solutions. Results show that after suitable parameter tuning, ACO is highly effective within interactive search and out-performs evolutionary algorithms with respect to increasing numbers of attributes and methods in the software design problem. However, when larger numbers of classes are present in the software design, an evolutionary algorithm using a naïve grouping integer-based representation appears more scalable.     

A two-level queueing system for interactive browsing and searching of video content

This paper presents a two-level queueing system for dynamic summarization and interactive searching of video content. Video frames enter the queueing system; some insignificant and redundant frames are removed; the remaining frames are pulled out of the system as top-level key frames. Using an energy-minimization method, the first queue removes the video frames that constitute the gradual transitions of video shots. The second queue measures the content similarity of video frames and reduces redundant frames. In the queueing system, all key frames are linked in a directed-graph index structure, allowing video content to be accessed at any level-of-detail. Furthermore, this graph-based index structure enables interactive video content exploration, and the system is able to retrieve the video key frames that complement the video content already viewed by users. Experimental results on four full-length videos show that our queueing system performs much better than two existing methods on video key frame selection at different compression ratios. The evaluation on video content search shows that our interactive system is more effective than other systems on eight video searching tasks. Compared with the regular media player, our system reduces the average content searching time by half.