Consulting support during conceptual database design in the presence of redundancy in requirements specifications: an empirical study

This study examines the efficacy of a consulting system for designing conceptual databases in reducing data modelling errors. Seventy-two subjects participated in an experiment requiring modelling of two tasks using the consulting system. About half the subjects used the treatment version and the other half used the control version. The control version resembled the treatment version in the look and feel of the interface; however, it did not embed the rules and heuristics that were included in the treatment version.Research findings suggest that subjects using the treatment version significantly outscored their control version counterparts. There was an interaction effect between system and prior knowledge—subjects who scored low in a pre-test benefited the most from the treatment version.This study has demonstrated that a consulting system can significantly reduce the incidence of errors committed by designers engaged in conceptual database modelling. Further, the system is robust and can prevent errors even in the presence of redundancy in user requirements.     

Integration of CORBA and object relational databases

CORBA is widely accepted as the open international standard for modelling and building comprehensive distributed systems. In most cases, CORBA architects have adopted relational databases for storage of persistent data. Among the issues that usually face architecture designers considering how to combine CORBA and standard relational database standards are fault tolerance, performance, and the extensibility and scalability of the systems. The research team involved with this paper found that the ODMG object database concept is useful to solve the issues encountered when integrating CORBA and relational database standards. The reference architecture, which the team devises, integrates CORBA and relational databases without compromise on the necessary transactional properties. The CORBA standard object transaction service and concurrency control service are reused. The team also develop an object relational data modelling tool—Latte—that supports the overall design intention as well the development paradigms for the proposed architecture. The implementation of the system is useful to CORBA, ODMG, and relational database architects because it provides a unified modelling and programming paradigm capable of solving the problems of managing mission-critical distributed data. Thus, we present a case study of combining different international standards to build a comprehensive system.     

Using a knowledge learning framework to predict errors in database design

Conceptual data modeling is a critical but difficult part of database development. Little research has attempted to find the underlying causes of the cognitive challenges or errors made during this stage. This paper describes a Modeling Expertise Framework (MEF) that uses modeler expertise to predict errors based on the revised Bloom's taxonomy (RBT). The utility of RBT is in providing a classification of cognitive processes that can be applied to knowledge activities such as conceptual modeling. We employ the MEF to map conceptual modeling tasks to different levels of cognitive complexity and classify current modeler expertise levels. An experimental exercise confirms our predictions of errors. Our work provides an understanding into why novices can handle entity classes and identifying binary relationships with some ease, but find other components like ternary relationships difficult. We discuss implications for data modeling training at a novice and intermediate level, which can be extended to other areas of Information Systems education and training.     

How do instructional designers use automated instructional design tool?

The purpose of this study was to investigate the use of an automated design tool by naive, novice, and expert instructional designers. A talk-aloud protocol, attitude survey, performance assessment, and direct observation were used to gather data. While the expert designers used the tool, they used it as a word processor with a rich database of instructional strategies. The novice designers relied on the tool for advice, guidance, and assistance in completing all the design tasks. Non-designers used the tool for learning about design.     

A conceptual database design approach based on rules and heuristics

Conceptual and logical database design are complex tasks for non-expert designers. Currently, the popular data models for conceptual and logical database design are the entity–relationship (ER) and the relational model, respectively. Logical design methodologies for relational databases have relied on mathematically rigorous approaches which are impractical, or textbook approaches which do not provide the rich constructs to capture real applications. Consequently, designers have to use their intuition to develop their own rules and heuristics. There is a need, therefore, to develop practical rules and heuristics that can be used to handle the complexity of design in real applications. This paper proposes a realistic and detailed approach for conceptual design using the ER model for relational databases. The approach is based on four rules that specify the order in which various types of relationships must be modelled, three rules that pertain to detection of derived relationships, and three heuristics based on observation of constructs in real applications. The approach is illustrated by many examples.     

Articulation of web site design constraints: Effects of the task and designers’ expertise

This paper aims at contributing to a better understanding of the cognitive activities of web site designers and, more precisely, their articulation and satisfaction of various design constraints. In this paper, we first present an experiment in which professional and novice designers have to evaluate a web site developed for reflecting usability errors identified in web sites. Then, the results obtained in this evaluation task are compared with results previously obtained in a design task, in which professional and novice designers had to create a web site. Data analyses focused on the number and nature of constraints articulated by designers in these two types of tasks (evaluation vs design). In particular, we distinguished constraints linked with the client of the site and constraints linked with the future web users. The obtained results show effects of both the level of expertise and the task. While designing, all of the designers focused mainly on constraints linked with the client. In contrast, while evaluating the web site, novices focused on constraints linked with the user, whereas professionals shared their attention between these two kinds of constraints (client vs user-oriented constraints). Based on these results, we conclude with ways for supporting designers’ activities.     

Investigating designers’ and users’ cognitive representations of products to assist inclusive interaction design

There is strong evidence of the importance of good interaction design in the creation of intuitive-use products. However, there is also a strong indication, both in the literature and in the study with designers documented in this paper, that despite this evidence designers get little support in adequately representing, analysing and comparing design and user information. Since designers require a practical and relatively easy-to-use support tool that would enable them to better understand cognitive processes of users and evaluate the accessibility and usability of different product features, this paper proposes the Goals-Actions-Beliefs-Objects (GABO) modelling approach that can form the basis of such a tool for designers. The four distinct stages of the GABO approach are designed to assess and compare designers and users’ understanding and usage of everyday products. The evaluation results of the GABO approach with eight product designers have indicated that designers find it useful and effective in identifying the key similarities and differences in the understanding of designers and users.     

Real-time performance modelling of a Sustained Attention to Response Task

Vigilance declines when exposed to highly predictable and uneventful tasks. Monotonous tasks provide little cognitive and motor stimulation and contribute to human errors. This paper aims to model and detect vigilance decline in real time through participants' reaction times during a monotonous task. A laboratory-based experiment adapting the Sustained Attention to Response Task (SART) is conducted to quantify the effect of monotony on overall performance. Relevant parameters are then used to build a model detecting hypovigilance throughout the experiment. The accuracy of different mathematical models is compared to detect in real time – minute by minute – the lapses in vigilance during the task. It is shown that monotonous tasks can lead to an average decline in performance of 45%. Furthermore, vigilance modelling enables the detection of vigilance decline through reaction times with an accuracy of 72% and a 29% false alarm rate. Bayesian models are identified as a better model to detect lapses in vigilance as compared with neural networks and generalised linear mixed models. This modelling could be used as a framework to detect vigilance decline of any human performing monotonous tasks.

Statement of Relevance: Existing research on monotony is largely entangled with endogenous factors such as sleep deprivation, fatigue and circadian rhythm. This paper uses a Bayesian model to assess the effects of a monotonous task on vigilance in real time. It is shown that the negative effects of monotony on the ability to sustain attention can be mathematically modelled and predicted in real time using surrogate measures, such as reaction times. This allows the modelling of vigilance fluctuations.     

Touch and design: novel haptic interfaces for the generation of high quality surfaces for industrial design

This paper presents the results of a research project aimed at developing haptic tools for virtual shape modelling resembling real tools like rakes and sandpaper used by modelers and designers in the real workshop. The developed system consists of a CAD (computer aided design) system enhanced with intuitive designer-oriented interaction tools and modalities. The system requirements have been defined on the basis of the observation of designers during their daily work, and translating the way they model shapes using hands and craft tools into specifications for the modelling system based on haptic tools.     

Maintenance error reduction strategies in nuclear power plants, using root cause analysis

This study proposes a conceptual model of maintenance tasks to facilitate the identification of root causes of human errors in carrying out such tasks in nuclear power plants. Based on this model, an external/internal classification scheme was developed to discover the root causes of human errors. As a consequence, certain policies pertaining to human error prevention or correction were proposed.     

Integration of task networks and cognitive user models using coloured Petri nets and its application to job design for safety and productivity

Changes of task demands due to unforeseen events and technological changes can cause variations in job design such as modifications to job procedures and task allocation. Failure to adapt to job design variations can lead to human errors that may have severe consequences for system safety. Existing techniques for task modelling cannot adequately model how task networks can be adapted to changing work conditions and task demands. Therefore, there is a need to integrate task networks with cognitive user models that indicate how operators process information, make decisions, or cope with suspended tasks and errors. The work described here presents a tool for integrating task and cognitive models using coloured Petri nets. The cognitive user model comprises two modules of attention management (selective and divided attention), a module of memory management of suspended tasks and a module of work organization. Performance Shaping Factors (e.g., workload, fatigue and mental-tracking load) are calculated at any point in time to take into account the context of work (e.g., competing activities, errors and suspended tasks). Different types of human error can be modelled for rule-based behaviours required in proceduralized work environments. Simulation analysis and formal analysis techniques can be applied to process control tasks to verify job procedures, workload management strategies and task allocation schemes in response to technological changes and unfamiliar events.     

Privacy threats in a mobile enterprise social network

The ‘Instant Knowledge’ system is an enterprise based social network that aims to introduce employees of the enterprise to contacts within the organization who may have skills relevant to particular tasks. The skills database is maintained through context-aware devices, and mobile devices in particular. The aim is to populate the database automatically based on user context data and to provide automatic introductions, again based on context data. This paper examines the security and privacy implications of this system and shows that while threat modelling on its own provides a solid base from which to secure the system, this is not enough to ensure that all privacy issues are considered. This is demonstrated by applying a mis-use case analysis that shows how personal identifying information can be inadvertantly leaked to malicious parties.     

Redefining the role of computers in architecture: from drafting/modelling tools to knowledge-based design assistants

The use of computers for automating the processes of design and manufacture promised significant improvements in designer's productivity and products' quality, neither of which, so far, have been realized in architectural design.This paper argues that in order to realize such improvements the modelling/drafting role computers have been assigned in architectural design should be changed, so that computers will become intelligent assistants to designers, relieving them from the need to perform the more trivial design tasks and augmenting their decision making capabilities.To support this argument, architectural design is modelled as a search process in a space of alternative solutions, seeking one or more solutions that satisfy certain design criteria. Design is shown to be a special case of general problem-solving processes, and thus comprised of two major components: design states and the generator/test cycle that facilitates transitions between them. It is then shown that the symbolic representation capabilities of computers qualify them to simulate such design states and the generate/test cycle, using techniques that were developed independently in the fields of geometric modelling and artificial intelligence. A conceptual framework of a knowledge-based computer-aided design system, which brings these techniques to bear on architectural problems, is presented, and its potential for increasing the utility of computers in the design of buildings is discussed.     

The evaluation of access costs in object databases

Unfortunately, there is at present nothing to assist the system architect at design-time to determine whether a proposed architecture based on an object-oriented database system will perform as required. The problem is complex, the choice of suitable modelling approach difficult, and a construction of a model is often abstruse. In this paper we concentrate on a major model component: that describing the access of objects in a centralised database. We present the background for the research (modern corporate IS architectures), the choices we have made, the prototype design, and the mathematical model of the cost of object database access. We conclude the paper by describing a validation of the model and how it can be generalised. The paper has a number of objectives: first, to dispel the myth that performance modelling of object-oriented systems is an immensely difficult task; second, to show that techniques which have been in existence for some time for modelling are applicable, with some modification, to aspects of object-oriented database performance prediction; and, third, to detail a specific case study of access cost modelling which provides enough information to be replicated by other workers across a number of object-oriented database products.     

Using task analysis to improve usability of fatigue modelling software

The design of any interactive computer system requires consideration of both humans and machines. Software usability is one aspect of human–computer interaction that can benefit from knowledge of the user and their tasks. One set of methods for determining whether an application enables users to achieve their predetermined goals effectively and efficiently is task analysis. In the present study, a task analysis was applied to the graphical user interface of fatigue modelling software used in industry. The task analysis procedure allowed areas of usability improvement to be identified and then addressed with alternate interface prototypes. The present method of task analysis illustrates a practical and efficient way for software designers to improve software usability, user effectiveness and satisfaction, by involving users in the design process.     

A simulation modelling tool for Distributed Virtual Environments

Distributed Virtual Environments simulate the behaviour and activities of a great number of users interacting in a virtual world over a wide area network. The size of the virtual worlds and the tremendous number of users that these environments are called to support require additional bandwidth and computational resources. For supporting large-scale Distributed Virtual Environments, extended infrastructure is needed in terms of both hardware and software. However, both researchers and application designers do not always have access to such an extended infrastructure and the assessment and evaluation of developed performance improvement techniques becomes extremely difficult. To address this issue, this paper presents a simulation modelling tool, called STEADiVE for networked servers Distributed Virtual Environments that could be used by designers for evaluating the performance of their approaches under different scenarios and system settings. The validation of the simulation modelling tool has showed that it achieves high accuracy in representing a real DVE system. STEADiVE comes to fill in the gap in the area of simulation tools for these systems.     

Scheduling algorithm based on prefetching in MapReduce clusters

Due to cluster resource competition and task scheduling policy, some map tasks are assigned to nodes without input data, which causes significant data access delay. Data locality is becoming one of the most critical factors to affect performance of MapReduce clusters. As machines in MapReduce clusters have large memory capacities, which are often underutilized, in-memory prefetching input data is an effective way to improve data locality. However, it is still posing serious challenges to cluster designers on what and when to prefetch. To effectively use prefetching, we have built HPSO (High Performance Scheduling Optimizer), a prefetching service based task scheduler to improve data locality for MapReduce jobs. The basic idea is to predict the most appropriate nodes for future map tasks based on current pending tasks and then preload the needed data to memory without any delaying on launching new tasks. To this end, we have implemented HPSO in Hadoop-1.1.2. The experiment results have shown that the method can reduce the map tasks causing remote data delay, and improves the performance of Hadoop clusters.     

A unified approach to content-based and fault-tolerant music recognition

In this paper, we propose a unified approach to fast index-based music recognition. As an important area within the field of music information retrieval (MIR), the goal of music recognition is, given a database of musical pieces and a query document, to locate all occurrences of that document within the database, up to certain possible errors. In particular, the identification of the query with regard to the database becomes possible. The approach presented in this paper is based on a general algorithmic framework for searching complex patterns of objects in large databases. We describe how this approach may be applied to two important music recognition tasks: The polyphonic (musical score-based) search in polyphonic score data and the identification of pulse-code modulation audio material from a given acoustic waveform. We give an overview on the various aspects of our technology including fault-tolerant search methods. Several areas of application are suggested. We describe several prototypic systems we have developed for those applications including the notify! and the audentify! systems for score- and waveform-based music recognition, respectively.     

Knowledge acquisition using VRML and the unified modelling language: the case of the RGB computer room

This paper describes the development of knowledge acquisition strategies for computing systems that aid designers in the construction of intelligent, heterogeneous, dynamic computational models of the built environment. The project uses a structure–behaviour–function model of the environment. The modelling strategy uses Virtual Reality Modelling Language (VRML) as a prototyping tool for constructing the built environment models. Unified Modelling Language (UML), a visual object oriented modelling language, is used in a reverse engineering mode as part of the knowledge acquisition strategy.