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Empirical studies comparing the effectiveness of visual languages versus textual languages have rarely been attempted. We describe an experiment conducted on programmers solving vector and matrix manipulation tasks using the visual language Forms/3, the textual language Pascal, and a textual matrix manipulation language with the capabilities of APL. Our motivation, experimental approach, some of the difficulties experienced in attempting this type of empirical study, and a summary of the experimental results and insights gained are presented. >

The environments that programmers traditionally use for problem-solving-with separate modes and tools for writing, compiling, testing, visualizing and debugging-derive their basic structure from historical accident, and take little advantage of human-computer interaction (HCI) research into the cognitive issues of programming. We believe that neglect of these issues impedes programmers' ability to produce reliable, maintainable software. Visual programming languages (VPLs) have begun to address this problem by creating more flexible, less modal programming environments, and we have taken a step further in this direction. In this paper, we describe a VPL in which programmers can modelessly steer as they specify, visualize, explore and alter the behavior of a program while traveling through the program's logical time. This approach supports two often-neglected cognitive principles that HCI research shows can help programmers in their problem-solving.

We believe concreteness, direct manipulation and responsiveness in a visual programming language increase its usefulness. However, these characteristics present a challenge in generalizing programs for reuse, especially when concrete examples are used as one way of achieving concreteness. In this paper, we present a technique to solve this problem by deriving generality automatically through the analysis of logical relationships among concrete program entities from the perspective of a particular computational goal. Use of this technique allows a fully general form-based program with reusable abstractions to be derived from one that was specified in terms of concrete examples and direct manipulation. >

A class of visual programming languages whose members share a common group of underlying principles is identified. In this class (the demand-driven temporal-assignment visual language model), the elimination of certain duplicate computations is a natural by-product of the model. The potential time and space complexity characteristics for visual languages based on this model are discussed, and a method that makes use of these characteristics is presented. >

Although spreadsheets can be argued to be the most widely used visual programming languages (VPLs) today, most are very limited compared to other VPLs, supporting only a few built-in types and offering only primitive support for code reuse. The inheritance mechanisms of object oriented programming might seem to offer help for the latter problem, but incorporating these mechanisms in a traditional way would introduce concepts foreign to spreadsheets, such as message passing. We present similarity inheritance, a new approach to inheritance that is suitable for seamless integration into the spreadsheet paradigm. We first explain the model independently of any implementation, and then present a prototype implementation in the research spreadsheet VPL Forms/3. We show that bringing inheritance functionality to the spreadsheet paradigm can be done using the widely understood idea of copy/paste. Further, we show why the approach requires the presence of a live, visual environment.

An increasingly common characteristic in visual programming languages (VPLs) is level 4 liveness-the constant monitoring of the system state with continuous redisplay as events arrive and computations progress. However, level 4 liveness can be expensive. We present an implementation method that supports level 4 liveness in declarative VPLs, ensuring without "unreasonable" cost that all values on the screen are correctly updated as computations progress. The method is especially well suited for the growing class of declarative VPLs that display continuously time varying calculations and graphics, such as GUI specification VPLs, event based or reactive VPLs, scientific visualization VPLs, or graphical simulation VPLs.

Until now, attempts to extend the one way constraint evaluation model of the spreadsheet paradigm to support complex objects, such as colored circles or user defined types, have led to approaches featuring either a direct way of creating objects graphically or strong compatibility with the spreadsheet paradigm, but not both. This inability to conveniently go beyond numbers and strings without straying outside the spreadsheet paradigm has been a limiting factor in the applicability of spreadsheets. We present a technique that removes this limitation, allowing complex objects to be programmed directly-and in a manner that fits seamlessly within the spreadsheet paradigm-using direct manipulation and gestures. An empirical study has shown that programmers can use this technique to program complex objects faster and with fewer errors. We show that the graphical definitions technique not only expands the applicability of spreadsheet languages, it also adds to their support for exploratory programming and to their scalability.

Although the idea of reusing code is very appealing, effective reuse has long been acknowledged as a problem. To help address the difficulties, many advocate strong management commitment to code reuse, leading to the treatment of code as an asset to be carefully managed in a well-organized repository. However, the advent of the Web may bring a change to this outlook encouraging informal, loosely-organized code repositories. Already, for both textual and visual languages, informal repositories are beginning to emerge, featuring a high rate of change and few controls over what a producer must do to submit code. We present techniques to address some aspects of code reuse in this kind of informal, evolving environment. These techniques build upon characteristics found in many visual programming languages. Using these techniques, our approach is able to eliminate the special work traditionally required of the producer, while still supporting the consumer's reuse efforts within these immature, evolving repositories.

Form based visual programming languages, which include electronic spreadsheets and a variety of research systems, have had a substantial impact on end user computing. Research shows that form based visual programs often contain faults, and that their creators often have unwarranted confidence in the reliability of their programs. Despite this evidence, we find no discussion in the research literature of techniques for testing or assessing the reliability of form based visual programs. The paper addresses this lack. We describe differences between the form based and imperative programming paradigms, and discuss effects these differences have on strategies for testing form based programs. We then present several test adequacy criteria for form based programs, and illustrate their application. We show that an analogue to the traditional "all-uses" dataflow test adequacy criterion is well suited for code based testing of form based visual programs: it provides important error detection ability, and can be applied more easily to form based programs than to imperative programs.

Until now, only users of textual programming languages have enjoyed the fruits of algorithm animation. Users of visual programming languages (VPLs) have been deprived of the unique semantic insights algorithm animation offers. To begin solving this shortcoming, we have seamlessly integrated algorithm animation capabilities into the VPL Forms/3. Our research shows how a declarative VPL that is responsive can provide features not found in other algorithm animation systems.

E-commerce has begun to evolve beyond simple web pages to more sophisticated ways of conducting e-business transactions, such as through electronic advertising, negotiation, and delivery. However, to participate in these advances requires the skills of professional programmers, and end-user owners of small businesses often cannot justify this expense. In this paper, we present FAR, an end-user language to offer and deliver e-services. The novel aspects of FAR are its support of small e-services and its multiparadigm approach to combining ideas from spreadsheets and rule-based programming with drag-and-drop web page layout devices.

Spreadsheets are among the most common form of software in use today. Unlike more traditional forms of software however, spreadsheets are created and maintained by end users with little or no programming experience. As a result, a high percentage of these "programs" contain errors. Unfortunately, software engineering research has for the most part ignored this problem. We have developed a methodology that is designed to aid end users in developing, testing, and maintaining spreadsheets. The methodology communicates testing information and information about the impact of cell changes to users in a manner that does not require an understanding of formal testing theory or the behind the scenes mechanisms. The paper presents the results of an empirical study that shows that, during maintenance, end users using our methodology were more accurate in making changes and did a significantly better job of validating their spreadsheets than end users without the methodology.

Specifying varying speeds and temporal relationships is necessary when programming graphical animations, but support for temporal programming has usually been done by adding new language features to a VPL, and these features must be mastered over and above the other aspects of the VPL. However, some researchers have believed that time should be able to be treated like just another dimension. We explore whether temporal programming can indeed be done using exactly the same devices as in spatial programming in grid-oriented VPLs. Toward this end, we provide a continuum of models aimed at this goal, with their advantages and disadvantages. Also, we identify core issues that help illuminate the essence of the problem.

We define a unit system for end-user spreadsheets that is based on the concrete notion of units instead of the abstract concept of types. Units are derived from header information given by spreadsheets. The unit system contains concepts, such as dependent units, multiple units, and unit generalization, that allow the classification of spreadsheet contents on a more fine-grained level than types do. Also, because communication with the end user happens only in terms of objects that are contained in the spreadsheet, our system does not require end users to learn new abstract concepts of type systems.

Although there has been recent research into ways to design visual programming languages and environments, little attention has been given to systematic testing in these languages, and what work has been done does not address "power" features such as recursion. In this paper, we discuss two possible ways the "What You See Is What You Test" methodology could be extended to accommodate recursion. The approaches are presented in terms of their testing theoretic aspects and then implementation strategies and algorithms. Since the goal is to help the people using these languages, we also present an empirical study and use its results to inform our choice as to which of the two approaches to adopt.

To investigate the hypothesis that respiratory gas exchange and, in particular, the O2consumption (V˙o2) response to exercise is altered after a 21-day expedition to 6,194 m, five male climbers (age 28.2 ± 2 yr; weight 76.9 ± 4.3 kg; means ± SE) performed a progressive and prolonged two-step cycle test both before and 3–4 days after return to sea level. During both exercise tests, a depression ( P < 0.05) inV˙o2(l/min) and an increase ( P < 0.05) in minute ventilation (V˙e btps; l/min) and respiratory exchange ratio were observed after the expedition. These changes occurred in the absence of changes in CO2production (l/min). During steady-state submaximal exercise, net efficiency, calculated from the rates of the mechanical power output to the energy expended (V˙o2) above that measured at rest, increased ( P < 0.05) from 25.9 ± 1.6 to 31.3 ± 1.3% at the lighter power output and from 24.4 ± 1.3 to 29.5 ± 1.5% at the heavy power output. These changes were accompanied by a 4.5% reduction ( P< 0.05) in peak V˙o2(3.99 ± 0.17 vs. 3.81 ± 0.18 l/min). After the expedition, an increase ( P < 0.05) in hemoglobin concentration (15.0 ± 0.49 vs. 15.8 ± 0.41 g/100 ml) was found. It is concluded that, because resting V˙o2was unchanged, net efficiency is enhanced during submaximal exercise after a mountaineering expedition when the exercise is performed soon after return to sea level conditions.

To investigate the hypothesis that intrinsic changes in sarcoplasmic reticulum (SR) Ca2+-sequestration function can be implicated in postcontractile depression (PCD) of force in humans, muscle tissue was obtained from the vastus lateralis and determinations of maximal Ca2+uptake and maximal Ca2+-ATPase activity were made on homogenates obtained before and after the induction of PCD. Eight untrained females, age 20.6 ± 0.75 yr (mean ± SE), performed a protocol consisting of 30 min of isometric exercise at 60% maximal voluntary contraction and at 50% duty cycle (5-s contraction and 5-s relaxation) to induce PCD. Muscle mechanical performance determined by evoked activation was measured before (0 min), during (15 and 30 min), and after (60 min) exercise. The fatiguing protocol resulted in a progressive reduction ( P < 0.05) in evoked force, which by 30 min amounted to 52% for low frequency (10 Hz) and 20% for high frequency (100 Hz). No force restoration occurred at either 10 or 100 Hz during a 60-min recovery period. Maximal SR Ca2+-ATPase activity (nmol ⋅ mg protein−1⋅ min−1) and maximal SR Ca2+uptake (nmol ⋅ mg protein−1⋅ min−1) were depressed ( P < 0.05) by 15 min of exercise [192 ± 45 vs. 114 ± 8.7 and 310 ± 59 vs. 205 ± 47, respectively; mean ± SE] and remained depressed at 30 min of exercise. No recovery in either measure was observed during the 60-min recovery period. The coupling ratio between Ca2+-ATPase and Ca2+uptake was preserved throughout exercise and during recovery. These results illustrate that during PCD, Ca2+uptake is depressed and that the reduction in Ca2+uptake is due to intrinsic alterations in the Ca2+pump. The role of altered Ca2+sequestration in Ca2release, cytosolic-free calcium, and PCD remains to be determined.

Is it possible to achieve some of the benefits of formal testing within the informal programming conventions of the spreadsheet paradigm? We have been working on an approach that attempts to do so via the development of a testing methodology for this paradigm. Our "What You See Is What You Test" (WYSIWYT) methodology supplements the convention by which spreadsheets provide automatic immediate visual feedback about values by providing automatic immediate visual feedback about "testedness". In previous work we described this methodology (G. Rothermal et al., 1998). We present empirical data about the methodology's effectiveness. Our results show that the use of the methodology was associated with significant improvement in testing effectiveness and efficiency, even with no training on the theory of testing or test adequacy that the model implements. These results may be due at least in part to the fact that use of the methodology was associated with a significant reduction in overconfidence.

Visual programming languages aim to promote usability, but are rarely examined for it. One reason is the difficulty of designing successful experimental evaluations. We propose the cognitive walkthrough as an aid to improve experimental designs. This is a novel application of an HCI-derived technique designed for evaluating interfaces rather than experiments. The technique focuses on the potential difficulties of novice users and is therefore particularly suited for evaluating the programming situation, which is knowledge-based and non-routine. We describe an empirical study performed without benefit of a walkthrough and show how the study was improved by a series of walkthroughs. We found the method to be quick to use, effective at improving the experimental design, and usable by non-specialists.

Millions of people program to support their work but don't call themselves programmers. The field of end-user software engineering is concerned with helping these people create reliable, dependable, and reusable programs, without distracting them from their primary tasks. This special issue of IEEE Software presents a selection of research from this field, providing a glimpse of some of the exciting advances made in past 10 years of research and development.

Although there has been considerable research into ways to design visual programming environments to improve the processes of creating new programs and of understanding existing ones, little attention has been given to helping users of these environments test their programs. This feature would be particularly important for systems aimed at end users, since testing is the primary device they use to determine whether their programs are correct. To help address this need, we introduce two visual approaches to testing large grids in spreadsheet systems. This work scales up a visual testing methodology we previously developed for individual cells. The approaches are tightly integrated into Forms/3, a visual spreadsheet language, and communication with the user happens solely through the use of checkbox devices and coloring mechanisms. The intent of this work is to bring to end users at least some of the benefits of formalized notions of testing, without requiring knowledge of testing beyond a naive level.

Observation 2: Researchers in visual programming languages would like to take advantage of the new choices afforded by Observation 1 to design "better" languages than were possible before. Although there are many possible views as to what it means for one programming language to be better than another, most agree that programming language A is better than another programming language B if humans are more likely to correctly create, understand, and/or change a program using A than using B.

Continuous visual feedback is becoming a common feature in direct-manipulation systems of all kinds -- from demonstrational macro builders to spreadsheet packages to visual programming languages featuring direct manipulation. But does continuous visual feedback actually help in the domain of programming? There has been little investigation of this question, and what evidence there is from related domains points in conflicting directions. To advance what is know about this issue, we conducted an empirical study to determine whether the inclusion of continuous visual feedback into a direct-manipulation programming system helps with one particular task: debugging. Our results were that although continuous visual feedback did not significantly help with debugging in general, it did significantly help with debugging in some circumstances. Our results also indicate three factors that may help determine those circumstances.

Until now, only users of textual programming languages have enjoyed the fruits of algorithm animation. Users of visual programming languages (VPLs) have been deprived of the unique semantic insights algorithm animation offers, insights that would foster the understanding and debugging of visual programs. To begin solving this shortcoming, we have seamlessly integrated algorithm animation capabilities into Forms/3, a declarative VPL in which evaluation is the continuous maintenance of a network of one-way constraints. Our results show that a VPL that uses this constraint-based evaluation model can provide features not found in other algorithm animation systems.

Objective: To determine whether gMSDx status correlates with additional measures of disease activity and can assist with differential diagnosis of MS. Background Multiple Sclerosis (MS) is an autoimmune and neurodegenerative disease. No single biomarker can be used to reliably establish a diagnosis of MS, or to differentiate it from other diseases. In addition to specific features of CNS autoimmunity in MS, serologic evidence of general autoimmunity, including elevated ANA and EBV titers, has been reported. A recently commercialized test (gMSDx from Glycominds) that measures antibodies against specific glycans (GAGA4 IgM, or GM) indicates 57% sensitivity and 89-91% specificity for MS diagnosis when positive. Increased titers result in less sensitivity, but greater specificity. Glycans are major surface components of cells including white blood cells and anti-glycan antibodies are reported to be produced in response to pathogens. Specific anti-glycan antibodies have been demonstrated in both MS and Crohn9s Disease. Design/Methods: Medical records of patients referred for treatment or evaluation of possible multiple sclerosis or central nervous system inflammatory disease were examined for biographical information, disease characteristics and serologic and CSF data, including serum GAG4 IgM. Results: In this cohort, 90% of patients with a definite diagnosis of MS were either serum positive for oligoclonal bands (OCB) or anti-glycan antibodies, while only 10 % of patients were positive for both. CSF from 60% of patients were gMSDx positive, but negative for OCB. Females were more likely to be positive, concurring with other reports. Conclusions: The data suggest lack of correlation between the presence of (OCB) and anti-glycan antibodies, measured by the Glycominds test. This may reflect pathogenetic heterogeneity in the MS population. Additional study is required to more firmly establish the utility of this specific biomarker in MS. Supported by: USC Undergraduate Provost Fellowship. Donation from the Keough Family. Disclosure: Dr. Burnett has received personal compensation for activities with Biogen Idec, Serono, Inc., Pfizer Inc, Bayer Healthcare, Acorda Therapeutics, and Teve Neuroscience. Dr. Kabadi has nothing to disclose.

Visual programming language research has evolved greatly since its early days. At first, attempts at visual programming mostly took the form of flowchart-like diagrams. But in recent years, a wide number of innovative approaches have been incorporated into visual languages, including object-oriented programming, form-based programming, programming by demonstration, and dataflow programming. Unfortunately, while many of these systems represent important ideas, only a few have been successful as complete visual programming languages. This tutorial explains why this is true, and describes ways in which the problem can be addressed.This tutorial explores the issues behind the successes and failures of earlier approaches from a design perspective. It identifies characteristics of successful visual programming languages, and explains how to design an object-oriented language that maintains those characteristics. It shows solutions to a number of problems by looking at existing visual programming languages, including Prograph.

The increasing influence of visual technology on language environments that has resulted from the increasing availability of workstations is discussed. An evolution that began with the relatively straightforward translation of textual techniques into corresponding visual techniques and has progressed to uses of visual techniques that have no natural parallel using purely textural techniques is traced. Visual user interfaces, visual editing, and visual languages are surveyed. >

The present study deals with the criteria by which patients evaluate their physicians. Since the patient is typically a layman confronting a professional, the process of evaluation problems becomes problematic. Therefore, an attempt was made to: (a) investigate the specific behavioural expectations held by patients regarding physician role performance; and (b) explore the relative importance of perceived physician affective, procedural and administrative conformity in determining both the patients' general satisfaction and their assessment of physicians' technical competence. Two hundred and thirty-one patients, randomly selected from a Family Medical Centre in Winnipeg, Canada, responded to a mailed questionnaire which contained a Physician Conformity Index and measures of patient satisfaction and perception of physician technical competence. A correlational analysis of the data disclosed that the principal relationship appears to be between perceived physician affective conformity and general patient satisfaction. The findings of this study indicate that perceived physician conformity to patients' affective expectations is considerably more important in determining the patients' evaluation of physicians' role performance than perceived conformity to either procedural or administrative expectations. The paper concludes with a discussion of the various factors which may explain why this dimension of the patient—physician relationship plays such a major part in shaping patients' expectations and evaluation of perceived physician behaviour.

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Many machine-learning algorithms learn rules of behavior from individual end users, such as task-oriented desktop organizers and handwriting recognizers. These rules form a “program” that tells the computer what to do when future inputs arrive. Little research has explored how an end user can debug these programs when they make mistakes. We present our progress toward enabling end users to debug these learned programs via a Natural Programming methodology. We began with a formative study exploring how users reason about and correct a text-classification program. From the results, we derived and prototyped a concept based on “explanatory debugging”, then empirically evaluated it. Our results contribute methods for exposing a learned program’s logic to end users and for eliciting user corrections to improve the program’s predictions.

The purpose of this study was to investigate the hypothesis that a single, extended session of heavy exercise would be effective in inducing adaptations in energy metabolism during exercise in the absence of increases in oxidative potential. Ten healthy males [maximal aerobic power (V˙o2 peak) = 43.4 ± 2.2 (SE) ml ⋅ kg−1⋅ min−1] participated in a 16-h training session involving cycling for 6 min each hour at ∼90% of maximal oxygen consumption. Measurements of metabolic changes were made on tissue extracted from the vastus lateralis during a two-stage standardized submaximal cycle protocol before (Pre) and 36–48 h after (Post) the training session. At Pre, creatine phosphate (PCr) declined ( P < 0.05) by 32% from 0 to 3 min and then remained stable until 20 min of exercise at 60%V˙o2 peakbefore declining ( P < 0.05) by a further 35% during 20 min of exercise at 75%V˙o2 peak. Muscle lactate (mmol/kg dry wt) progressively increased ( P < 0.05) from 4.59 ± 0.64 at 0 min to 17.8 ± 2.7 and 30.9 ± 5.3 at 3 and 40 min, respectively, whereas muscle glycogen (mmol glucosyl units/kg dry wt) declined ( P < 0.05) from a rest value of 360 ± 24 to 276 ± 31 and 178 ± 36 at similar time points. During exercise after the training session, PCr and glycogen were not as depressed ( P < 0.05), and increases in muscle lactate were blunted ( P < 0.05). All of these changes occurred in the absence of increases in oxidative potential as measured by the maximal activities of citrate synthase and malate dehydrogenase. These findings are consistent with other studies, namely, that muscle metabolic adaptations to regular exercise are an early adaptive event that occurs before increases in oxidative potential.