Software Design

In the last twenty years, many different approaches to deal with Computer-Interpretable clinical Guidelines (CIGs) have been developed, each one proposing its own representation formalism (mostly based on the Task-Network Model) execution engine. We propose META-GLARE a shell for easily defining new CIG systems. Using META-GLARE, CIG system designers can easily define their own systems (basically by defining their representation language), with a minimal programming effort. META-GLARE is thus a flexible and powerful vehicle for research about CIGs, since it supports easy and fast prototyping of new CIG systems.

Talk about everything interior designers need to know every day:

Project mangement tools
Sequencing spaces
Design software
Digital presentation
Sustainability guidelines
standard dimensions tabels
Codes and accessibility
Contrast and color rules
paint types
Wall coverings
Flooring Types and specs
Natural and artificial light
Invisible systems
Drawing Basics

Automated medical diagnosis systems based on knowledge-oriented descriptions have gained momentum with the emergence of semantic descriptions. The objective of this paper is to propose a normalized design that solves some of the problems which have been detected by authors in previous tools. The authors bring together two different technologies to develop a new clinical decision support system: description logics aimed at developing inference systems to improve decision support for the prevention, treatment and management of illness and semantic technologies. Because of its new design, the system is capable of obtaining improved diagnostics compared with previous efforts. However, this evaluation is more focused in the computational performance, giving as result that description logics is a good solution with small data sets. In this paper, we provide a well-structured ontology for automated diagnosis in the medical field and a threefold formalization based on Description Logics with the use of Semantic Web technologies.

This paper describes an underwater walking robotic system being developed under the name AQUA, the goals of the AQUA project, the overall hardware and software design, the basic hardware and sensor packages that have been developed, and some initial experiments. The robot is based on the RHex hexapod robot and uses a suite of sensing technologies, primarily based on computer vision and INS, to allow it to navigate and map clear shallow-water environments. The sensor-based navigation and mapping algorithms are based on the use of both artificial floating visual and acoustic landmarks as well as on naturally occurring underwater landmarks and trinocular stereo.

We report on a case study to assess the use of an advanced knowledge-based software design technique with programmers who have not participatedin the technique's development. We use the KIDS approach to algorithm design to construct two global search algorithms that route baggage through a transportation net. Construction of the second algorithm involves extending the KIDS knowledge base. Experience with the case study leads us to integrate the approach with the spiral and prototyping models of software engineering, and to discuss ways to deal with incomplete design knowledge.

Software engineers and programmers deal with repeated problems and situations in the course of software design. This lead to the development of software design patterns, which can be defined as a description of an abstract solution for abstract design problems. Existing approaches to pattern application using computer tools, need the help and guidance of a human designer to select which design pattern to apply. The automation of this task opens the possibility of CASE design tools providing complete automation for the application of design patterns, and the offering new functionalities that can help the software designer to improve systems, and do better software reuse. In this paper we present an approach that automates design pattern selection and application. This approach is based on Case-Based Reasoning and WordNet, showing how they are combined to generate evolved software design diagrams. We also present an experimental study of our approach.

We present a foundational theory of software system re-liability based on components. The theory describes how component developers can design and test their components to produce measurements that are later used by system de-signers to calculate composite system reliability — ...

Security design patterns have been proposed recently as a tool for the improvement of software security during the architecture and design phases. Since the apperance of this research topic in 1997, several catalogs have emerged, and the security pattern community has produced significant contributions, with many related to design. In this paper, we survey major contributions in the state of the art in the field of security design patterns and assess their quality in the context of an established classification. From our results, we determined a classification of inappropriate pattern qualities. Using a Six Sigma approach, we propose a set of desirable properties that would prevent flaws in new design patterns, as well as a template for expressing them.

In this paper, we present an efficient coarse-tofine multiresolution framework for multidimensional scaling and demonstrate its performance on a large-scale nonlinear dimensionality reduction and embedding problem in a texture feature extraction step for the unsupervised image segmentation problem. We demonstrate both the efficiency of our multiresolution algorithm and its real interest to learn a nonlinear low-dimensional representation of the texture feature set of an image which can then subsequently be exploited in a simple clustering-based segmentation algorithm. The resulting segmentation procedure has been successfully applied on the Berkeley image database, demonstrating its efficiency compared to the best existing state-ofthe-art segmentation methods recently proposed in the literature.

Users at different levels of domain experience have very different needs. For example, a system designed to assist domain novices may frustrate experts and vice-versa. This is one of several challenges specific to building decision support systems for experience-centered domains. Examples of experience-centered domains include medical diagnosis [37], chess [15], [16], as well as most professional design or planning tasks [24]

This poster describes a technique for reconstructing tomographic images generated by a minitomograph scanner for soil science developed by Embrapa Agricultural Instrumentation using a parallel DSP architecture with an HEPC2E board from Hunt Engineering with two TMS320C40 processors from Texas Instruments. The software designed for visualization of bi-and tri-dimensional images uses Code Composer tool combined with Parallel C from 3L and Borland Builder C++. Reconstruction and interpolation tasks were distributed throughout the platform processors, using parallel algorithms in order to improve speed and processing power. The work resulted in an increase of about 15% in the system speed when compared with that reached using a classical platform at 200 MHz.

The methodology of recursive partition and amalgamation in biostatistics is presented and a FORTRAN program for its implementation, RECPAM, is described. RECPAM can be used to obtain classifications of patients according to several criteria commonly occurring in clinical biostatistics: an example is prognostic classification based on survival data. Classes are defined by simple statements, expressed in clinical terms, about predictor variables (e.g. prognostic factors). Special features of RECPAM are: the possibility of implementing a variety of classification criteria, the integration of recursive partition and amalgamation, and the availability of several strategies for constructing classification trees. A simple example to illustrate input and output features is given. The scope and flexibility of RECPAM will be illustrated in greater detail in a subsequent paper.

Microarray based transcription profiling is now a consolidated methodology and has widespread use in areas such as pharmacogenomics, diagnostics and drug target identification. Large-scale microarray studies are also becoming crucial to a new way of conceiving experimental biology. A main issue in microarray transcription profiling is data analysis and mining. When microarrays became a methodology of general use, considerable effort was made to produce algorithms and methods for the identification of differentially expressed genes. More recently, the focus has switched to algorithms and database development for microarray data mining. Furthermore, the evolution of microarray technology is allowing researchers to grasp the regulative nature of transcription, integrating basic expression analysis with mRNA characteristics, i.e. exon-based arrays, and with DNA characteristics, i.e. comparative genomic hybridization, single nucleotide polymorphism, tiling and promoter structure. In this article, we will review approaches used to detect differentially expressed genes and to link differential expression to specific biological functions.

EPA is undertaking an effort to develop a new set of modeling tools for the estimation of emissions produced by on-road and off-road mobile sources. The product of this effort will be the Multi-scale mOtor Vehicle & equipment Emission System, hereby known as MOVES. The design of MOVES is guided by the following four considerations:(1) the model should encompass all pollutants (eg, HC, CO, NOx, particulate matter, air toxics, and greenhouse gases) and all mobile sources at the levels of resolution needed for the ...

Uncertainty can be harmful in some cases and beneficial in other cases. At the beginning, the software universe only appreciates the beneficial side of uncertainty, although it took advantage of it. Software is practically useless without uncertainty. Nowadays, uncertainty is more used as a tool but this is not recognized and it causes several problems. In that sense, this work proves uncertainty can be used as a tool in order: 1) to simplify descriptive and uncertainty complexity; it means, to reduce development and maintenance effort. 2) To analyse and forecast key properties of software engineering components. 3) To appreciate relations between these components and the harmonic place corresponding to each of them. In short, this work proves uncertainty dimension is a basic element in the current theoretical framework of software engineering.

We define three abstract protocols which are appropriate for characterising communications in real-time system designs. These protocols abstract from details of distribution and synchronisation. This makes them suitable for use early in the design process, before the details of hardware network and software design deployment are finalised. The specifications are given in CSP, and are shown by model-checking to be valid abstractions of various distributed and local implementations. The utility of the protocols is demonstrated by showing that important properties can be established of designs which employ them, such as whether data must be processed once, or whether it may be processed more than once

Binary component-based software updates that are efficient, safe and generic still remain a challenge. Most existing deployment systems that achieve this goal have to control the complete software environment of the user which is a barrier to adoption for both software consumers and producers. Binary change set composition is a technique that can be applied to deliver incremental, binary updates for component-based software systems in an efficient and non-intrusive way. This way application updates can be delivered more frequently, with minimal additional overhead for users and without sacrificing the benefits of component-based software development.

Course resolution earth observation satellites offer large data sets with daily observations at global scales. These data sets represent a rich resource that, because of the high acquisition rate, allows the application of time-series analysis methods. To research the application of these time-series analysis methods to large data sets, it is necessary to turn to highperformance computing (HPC) resources and software designs. This article presents an overview of the development of the HiTempo platform, which was designed to facilitate research into time-series analysis of hyper-temporal sequences of satellite image data. The platform is designed to facilitate the exhaustive evaluation and comparison of algorithms, while ensuring that experiments are reproducible. Early results obtained using applications built within the platform are presented. A sample model-based change detection algorithm based on the extended Kalman filter has been shown to achieve a 97% detection success rate on simulated data sets constructed fromMODIS time series. This algorithm has also been parallelized to illustrate that an entire sequence of MODIS tiles (415 tiles over 9 years) can be processed in under 19 minutes using 32 processors.

Lack of good user interfaces has been a major impediment to the acceptance and routine use of health-care professional workstations. Health-care providers, and the environment in which they practice, place strenuous demands on the interface. User interfaces must be designed with greater consideration of the requirements, cognitive capabilities, and limitations of the end-user. The challenge of gaining better acceptance and achieving widespread use of clinical information systems will be accentuated as the variety and complexity of multi-media presentation increases. Better understanding of issues related to cognitive processes involved in human-computer interactions is needed in order to design interfaces that are more intuitive and more acceptable to health-care professionals. Critical areas which deserve immediate attention include: improvement of pen-based technology, development of knowledge-based techniques that support contextual presentation, and development of new strategies and metrics to evaluate user interfaces. Only with deliberate attention to the user interface, can we improve the ways in which information technology contributes to the efficiency and effectiveness of health-care providers.

Design patterns, which encapsulate common solutions to the recurring design problems, have contributed to the increased reuse, quality and productivity in software design. We argue that hardware design patterns could be used for customizing and integrating the Intellectual Property (IP) components into Systemon-Chip designs. We formulate the role of design patterns in HW design, and describe their implementation using metaprogramming. We propose a Wrapper design pattern for adapting the behavior of the soft IPs, and demonstrate its application to the communication interface synthesis.

Quality improvement is central to Infection Prevention and Control (IPC) programs. Challenges may occur when applying quality improvement methodologies like process control charts, often due to the limited exposure of typical IPs. Because of this, our team created an open-source database with a process control chart generator for IPC programs. The objectives of this report are to outline the development of the application and demonstrate application using simulated data. We used Research Electronic Data Capture (REDCap Consortium, Vanderbilt University, Nashville, TN), R (R Foundation for Statistical Computing, Vienna, Austria), and R Studio Shiny (R Foundation for Statistical Computing) to create an open source data collection system with automated process control chart generation. We used simulated data to test and visualize both in-control and out-of-control processes for commonly used metrics in IPC programs. The R code for implementing the control charts and Shiny application c...

R. A R M O N AND Y. KOTT. 1993. A rapid, simple and sensitive direct bacteriophage presence detection method for 500 ml drinking water samples has been developed. The method includes a glass device consisting of a jar containing the water sample and an immersible probe filled with solidified soft agar containing bacterial host cells. Host bacteria in logarithmic phase were added to the experimental volume and the probe was submerged. T h e entire device was incubated in a water bath at 36°C. Plaques of somatic bacteriophage infecting Escherichia coli strain CN, , could be detected within 3 h. Male-specific bacteriophages infecting E. coli F + amp were detected within 6 h. Bacteriophage infecting the anaerobe Bacteroides fragilis subsp. fragilis HSP40 were detected after 8 h. Application of this device and the associated technique, enabled a one-step detection of 1 pfu of E. coli or Bact. fragilis specific bacteriophage in 500 ml drinking water samples.

In the last years, multi-agent systems (MAS) have proved more and more successful. The need of a quality software engineering approach to their design arises together with the need of new methodological ways to address important issues such as ontology representation, security concerns and production costs. The introduction of an extensive pattern reuse practice can be determinant in cutting down the time and cost of developing these systems. Patterns can be extremely successful with MAS (even more than with objectoriented systems) because the great encapsulation of agents allows an easier identification and disposition of reusable parts. In this paper we discuss our approach to the pattern reuse that is a phase of a more comprehensive approach to agent-oriented software design.

Intention-to-treat (ITT) in randomized controlled trials involves keeping participants in the treatment groups to which they were randomized regardless of whether they withdraw following randomization. Intention-totreat is a strategy for maintaining the integrity of randomization and strengthening the trial's internal validity. Although ITT is advocated by the Consolidated Standards of Reporting Trials (CONSORT) guidelines, there is confusion about what ITT means and little specific advice on how to achieve it. The purpose of this article is to present definitions of ITT and to suggest strategies for implementing ITT as a total design strategy in nursing clinical trials. Recommendations are offered regarding study planning, study design, subject retention, sampling, data collection, data analysis, and reporting within the context of ITT. ß

The testing and debugging of complex programs has always been one of the most cost-determining factors in software design. This is even more true when parallel programs are considered. Debugging them is often based on a debugging cycle. First we make an assumption about the probable source of the bug, and next the validity of this assumption is verified. By repeatedly applying this technique, we try to limit the search-space until eventually the bug is resolved. There is a great need however for powerful high-level tools that enable the localization of bugs without indulging in this time-consuming error-prone debugging cycle. This paper describes such a high-level debugging tool, based on the animation of a program on its hierarchical-graphical representation.

Water resources management is increasingly dealing with competing demands for fixed or diminishing available supplies. In this , the allocation and accounting of water consumption between competing users, including environmental uses, plays a critical role. Various software tools have been developed to cover aspects of water resources planning and allocation, operation, and catchment management. In line with the requirements of water management agencies, attention is turning to the development of integrated tools with a broad range of capabilities that include water resource planning under different climatic and allocation policies, water supply under various operating rules and user behaviour, and catchment management and ecosystem condition assessment under different management regimes. This paper describes a preliminary software structure for water allocation, planning and management, starting from the basic concepts of availability, supply, demand and accounting, and outlining t...

On May 18, 2009, British computer scientist Stephen Wolfram
officially launched a new search product called Wolfram
j
Alpha
(WA). This launch was preceded by months of speculation and
hype online about exactly what WA would be and how it would
compare to Google and other search engines. This article will
explore the basic features of WA, show some example queries
and results, and discuss the usefulness and limitations of this
new tool.
KEYWORDS  Computation, Internet, search engines, Wolfram
|Alpha

The analysis of UCR data provides a basis for crime prevention in the United States as well as a sound decision making tool for policy makers. The decisions made with the use of UCR data range from major funding for resource allocation down to patrol distribution by local police departments. The FBI collects and maintains the database of the Uniform Crime Reports (UCR), from 18,000 reporting police agencies nationwide. However, many of these data sets have missing, incomplete, or incorrect data points that render crime analysis less effective. UCR experts have stated that in the current form UCR data is unreliable and sporadic. Efforts have previously been made to design a software application to correct these necessary problems, but the application was deemed insufficient due to limited portability and usability. Software requirements restricted potential users and the user interface was ineffective. However, this previous work describes the functions needed to effectively clean and assess UCR data. This paper describes the design of an application used to clean, process, and correct UCR data so that ideal policy decisions can be made. Erroneous portions of the data will be found using the outlier detection function that is based on a statistical model of anomalous behavior. These methods incorporate sponsor specifications and user requirements. This project builds upon the GRASP (Geospatial Repository for Analysis and Safety Planning) project's goal of sharing information between law enforcement agencies. Eventually

Objectives. To implement and evaluate the effects of a simulated hospital pharmacy module using an electronic medical record on student confidence and abilities to perform hospital pharmacist duties. Design. A module was developed that simulated typical hospital pharmacist tasks. Learning activities were modified based upon student feedback and instructor assessment. Assessments. Ninety-seven percent of respondents reported full-time hospital internship experience and 72% had electronic medical record experience prior to completing the module. Mean scores on confidence with performing typical hospital pharmacist tasks significantly increased from the pre-module survey to the post-module survey from 1.5-2.9 (low comfort/confidence) to 2.0-3.4 (moderate comfort/confidence). Course assessments confirmed student achievement of covered competencies. Conclusions. A simulated hospital pharmacy module improved pharmacy students' hospital practice skills and their perceived comfort and confidence in completing the typical duties of a hospital pharmacist.

N-version programming has been proposed as a method of incorporating fault tolerance into software. Multiple versions of a program (i.e. ''N'') are prepared and executed in parallel. Their outputs are collected and examined by a voter,a nd, if theya re not identical, it is assumed that the majority is correct. This method depends for its reliability improvement on the assumption that programs that have been developed independently will fail independently.I nt his paper an experiment is described in which the fundamental axiom is tested. Atotal of twenty sevenversions of a program were prepared independently from the same specification at twou niversities and then subjected to one million tests. The results of the tests revealed that the programs were individually extremely reliable but that the number of tests in which more than one program failed was substantially more than expected. The results of these tests are presented along with an analysis of some of the faults that were found in the programs. Background information on the programmers used is also summarized. The conclusion from this experiment is that N-version programming must be used with care and that analysis of its reliability must include the effect of dependent errors.

A simple to use method was installed for the measurement of wounds contaminated with plutonium and americium by using a semiconductor detector. This technique does not explicitly require the knowledge of the detector efficiency but uses a plant 24tAm calibration source. A computer programme has also been developed for the quantification of the contamination according to the shape and the depth of the contaminant in the wound.

Meal lipids (LIP) and proteins (PRO) may influence the effect of insulin doses based on carbohydrate (CHO) counting in patients with type 1 diabetes (T1D). We developed a smartphone application for CHO, LIP, and PRO counting in daily food and assessed its usability in real-life conditions and potential usefulness. Ten T1D patients used the android application for 1 week to collect their food intakes. Data included meal composition, premeal and 2-hour postmeal blood glucose, corrections for hypo- or hyperglycemia after meals, and time for entering meals in the application. Meal insulin doses were based on patients' CHO counting (application in blinded mode). Linear mixed models were used to assess the statistical differences. In all, 187 meals were analyzed. Average computed CHO amount was 74.37 ± 31.78 grams; LIP amount: 20.26 ± 14.28 grams and PRO amount: 25.68 ± 16.68 grams. Average CHO, LIP, and PRO contents were significantly different between breakfast and lunch/dinner. The...

The focus of this paper is to have a critical look at the current game design literature through the analytical lenses of the current state of the art in design research. The aim is not to create yet another prescriptive framework for game design but rather an attempt to connect the game design studies to general design studies in a stimulating way.

This paper concerns the use of Information and Communications Technology (ICT) in music classrooms, with the focus on the secondary school music curriculum in the United Kingdom. In particular, it reports on a study of learners in a UK school using software designed to support practical music skills. The paper begins by briefly raising and summarising some key issues for the use of ICT in the UK music curriculum arising from current research and practice in music education. In this context the study is described, which was carried out in a British secondary school with 36 pupils in year 8 (aged %13). This study investigated whether a commercial CD-ROM entitled Teach Me Piano Deluxe, which was designed to teach music practical skills was able to support pupilsÕ acquisition of music keyboard skills. The results showed that there was a significant improvement in reading music (staff) notation and rhythm skills. The study suggests that this is one of the ways in which ICT may be useful for learning practical music skills in the music classrooms. Such potential improvement in practical skills may, in turn, enable pupils to approach music-based activities such as: composing, performing or listening in the classrooms, with greater confidence, a deeper level of understanding, and appreciation.

An emerging common trend in model-based design of embedded software and systems is the adoption of Domain-Specific Modeling Languages (DSMLs). While abstract syntax metamodeling enables the rapid and inexpensive development of DSMLs, the specification of DSML semantics is still a hard problem. In previous work, we have developed methods and tools for the semantic anchoring of DSMLs. Semantic anchoring introduces a set of reusable "semantic units" that provide reference semantics for basic behavioral categories using the Abstract State Machine (ASM) framework. In this paper, we extend the semantic anchoring framework to heterogeneous behaviors by developing a method for the composition of semantic units. Semantic unit composition reduces the required effort from DSML designers and improves the quality of the specification. The proposed method is demonstrated through a case study.

Object-oriented metrics have been validated empirically as measures of design complexity. These metrics can be used to mitigate potential problems in the software complexity. However, there are few studies that were conducted to formulate the guidelines, represented as threshold values, to interpret the complexity of the software design using metrics. Classes can be clustered into low and high risk levels using threshold values. In this paper, we use a statistical model, derived from the logistic regression, to identify threshold values for the Chidamber and Kemerer (CK) metrics. The methodology is validated empirically on a large open-source system-the Eclipse project. The empirical results indicate that the CK metrics have threshold effects at various risk levels. We have validated the use of these thresholds on the next release of the Eclipse project-Version 2.1-using decision trees. In addition, the selected threshold values were more accurate than those were selected based on either intuitive perspectives or on data distribution parameters. Furthermore, the proposed model can be exploited to find the risk level for an arbitrary threshold value. These findings suggest that there is a relationship between risk levels and object-oriented metrics and that risk levels can be used to identify threshold effects.

In this article, we describe a low-cost, dual-virtual-CPU hardware technology for embedded-systems security. We also present a case study of a programmable software design to exploit such hardware. This design integrates a rich operating system without requiring significant changes to it, while maintaining preemptive and real-time properties, exception handling, and power management.

Software Design and Media Design - tools to designMobile and Sensory Interfaces and Interactive EnvironmentsGeert de HaanCommunication, Media and Information TechnologySection Media Technology / Human Centered ICTRotterdam University of Applied SciencesP.O.Box 25035, 3001 HA, RotterdamThe [email protected]  paper  discusses  ETAG,  a  formal  model  for  design representation, and ETAG-based design, a method for user interface  design,  and  the  two  principal  facilities  they provide  to  accommodate  different  types  of  users  in  the design  of  user  interfaces.  The  paper  starts  with  an introduction  of  ETAG  as  a  design  representation.  This  is followed by a description of ETAG-based design and using the  notation  to  represent  relevant  aspects  of  the  work context.    Next,    we    discuss    the    differences    between computer  software  design  and  media  product  design, concluding  that  media  design  is  a  much  more  flexible, iterative  process  and  prototyping-based  process  in  which adaptation  of  the  design  of  mobile  applications  extends into    the    maintenance    phase.    To    cover    further developments towards  focussing  on user needs and wishes by  means  of  co-design  practices,  and  to  cover  for ubiquitous  computing  and  interaction  with  sensors  and interactive  environments,  we  propose  to  use  sensory  labs and  to  create  living  labs  to move  the  usability  lab into the real world

The long-term successful use of synthetic seismograms in traditional seismic reflection studies suggests that their implementation for high-resolution non-impulsive seismic sources would also be beneficial. We present here ChirCor v1.0, a program for managing physical-log data (P-wave velocity and density) and chirp-sonar seismograms, also equipped with a synthetic-trace generator, that could be used for correlating real seismograms to synthetics. The software, designed with a user-friendly graphic interface, is intended mainly for oceanographers and marine geologists as a tool for correlating highresolution seismic images and sediment cores. ChirCor v1.0 will be distributed as freeware for non-commercial purposes. We provide instructions regarding the use of the program together with a description of the algorithms implemented in the code; we also include an example of how to operate with the program based on the data collected during the MARMARA2001 marine geological expedition. r

'Open Source' is a 20 Á/40 year old approach to licensing and distributing software that has recently burst into public view. Against conventional wisdom this approach has been wildly successful in the general software market */probably because the openness lets programmers the world over obtain, critique, use, and build upon the source code without licensing fees. Linux, a UNIX-like operating system, is the best known success. But computer scientists at the University of California, Berkeley began the tradition of software sharing in the mid 1970s with BSD UNIX and distributed the major internet network protocols as source code without a fee. Medical informatics has its own history of Open Source distribution: Massachusetts General's COSTAR and the Veterans Administration's VISTA software have been distributed as source code at no cost for decades. Bioinformatics, our sister field, has embraced the Open Source movement and developed rich libraries of open-source software. Open Source has now gained a tiny foothold in health care (OSCAR GEHR, OpenEMed). Medical informatics researchers and funding agencies should support and nurture this movement. In a world where open-source modules were integrated into operational health care systems, informatics researchers would have real world niches into which they could engraft and test their software inventions. This could produce a burst of innovation that would help solve the many problems of the health care system. We at the Regenstrief Institute are doing our part by moving all of our development to the open-source model.

Software design is increasingly being recognized as an important factor in student learning when interacting with interactive geometry software (IGS). A categorization of the operations possible within an IGS is used to identify and analyse design decisions made in a number of current IGS programs: Cabri II Plus, Cabri 3D, Cinderella, GeoGebra and Geometer’s Sketchpad. The analysis, in the context of exploring the area of a circle, is focused on construction, dragging, and alternative spatial and semantic views. A wide diversity of both design issues and individual design decisions was identified, illustrating both the scarcity of research in this area and a number of inevitable tensions, such as between functionality and complexity, and between static and dynamic geometry, related to which future research questions might be posed.