Browsing functions in three-dimensional space for digital libraries

In order to get useful information from various kinds of information sources, we first apply a searching process with query statements to retrieve candidate data objects (called a hunting process in this paper) and then apply a browsing process to check the properties of each object in detail by visualizing candidates. In traditional information retrieval systems, the hunting process determines the quality of the result, since there are only a few candidates left for the browsing process. In order to retrieve data from widely distributed digital libraries, the browsing process becomes very important, since the properties of data sources are not known in advance. After getting data from various information sources, a user checks the properties of data in detail using the browsing process. The result can be used to improve the hunting process or for selecting more appropriate visualization parameters. Visualization relationships among data are very important, but will become too time-consuming if the amount of data in the candidate set is large, for example, over one hundred objects. One of the important problems in handling information retrieval from a digital library is to create efficient and powerful visualization mechanisms for the browsing process. One promising way to solve the visualization problem is to map each candidate data object into a location in three-dimensional (3D) space using a proper distance definition. In this paper, we will introduce the functions and organization of a system having a browsing navigator to achieve an efficient browsing process in 3D information search space. This browsing navigator has the following major functions: ?1. Selection of features which determine the distance for visualization, in order to generate a uniform distribution of candidate data objects in the resulting space. ?2. Calculation of the location of the data objects in 2D space using the selected features. ?3. Construction of 3D browsing space by combining 2D spaces, in order to find the required data objects easily. ?4. Generation of the oblique views of 3D browsing space and data objects by reducing the overlap of data objects in order to make navigation easy for the user in 3D space. ?Examples of this browsing navigator applied to book data are shown. Received: 15 December 1997 / Revised: June 1999     

Model-based detection,segmentation, and classification for image analysis using on-line shape learning

Detection, segmentation, and classification of specific objects are the key building blocks of a computer vision system for image analysis. This paper presents a unified model-based approach to these three tasks. It is based on using unsupervised learning to find a set of templates specific to the objects being outlined by the user. The templates are formed by averaging the shapes that belong to a particular cluster, and are used to guide a probabilistic search through the space of possible objects. The main difference from previously reported methods is the use of on-line learning, ideal for highly repetitive tasks. This results in faster and more accurate object detection, as system performance improves with continued use. Further, the information gained through clustering and user feedback is used to classify the objects for problems in which shape is relevant to the classification. The effectiveness of the resulting system is demonstrated in two applications: a medical diagnosis task using cytological images, and a vehicle recognition task. Received: 5 November 2000 / Accepted: 29 June 2001 Correspondence to: K.-M. Lee     

Touch-Space: Mixed Reality Game Space Based on Ubiquitous, Tangible, and Social Computing

This paper presents a novel computer entertainment system which recaptures human touch and physical interaction with the real-world environment as essential elements of the game play, whilst also maintaining the exciting fantasy features of traditional computer entertainment. Our system called ‘Touch-Space’ is an embodied (ubiquitous, tangible, and social) computing based Mixed Reality (MR) game space which regains the physical and social aspects of traditional game play. In this novel game space, the real-world environment is an essential and intrinsic game element, and the human’s physical context influences the game play. It also provides the full spectrum of game interaction experience ranging from the real physical environment (human to human and human to physical world interaction), to augmented reality, to the virtual environment. It allows tangible interactions between players and virtual objects, and collaborations between players in different levels of reality. Thus, the system re-invigorates computer entertainment systems with social human-to-human and human-to-physical touch interactions. Correspondence to: Professor A. Cheok, National University of Singapore, 10 Kent Ridge Crescent, Singapore 119260. Email: adriancheok@nus.edu.sg     

Necessary and sufficient conditions on information for causal message ordering and their optimal implementation

Summary. This paper formulates necessary and sufficient conditions on the information required for enforcing causal ordering in a distributed system with asynchronous communication. The paper then presents an algorithm for enforcing causal message ordering. The algorithm allows a process to multicast to arbitrary and dynamically changing process groups. We show that the algorithm is optimal in the space complexity of the overhead of control information in both messages and message logs. The algorithm achieves optimality by transmitting the bare minimum causal dependency information specified by the necessity conditions, and using an encoding scheme to represent and transmit this information. We show that, in general, the space complexity of causal 0message ordering in an asynchronous system is , where is the number of nodes in the system. Although the upper bound on space complexity of the overhead of control information in the algorithm is , the overhead is likely to be much smaller on the average, and is always the least possible. Received: January 1996 / Accepted: February 1998     

Application-controlled memory management in a single address space environment

With reference to a memory management system supporting the single address space abstraction and a uniform, persistent view of storage, we present a set of mechanisms that allow applications to exert explicit control over memory management activities. These mechanisms make it possible to move the contents of a virtual page to primary memory for fast processor access, or to push these contents back to secondary memory to free primary memory space. Our memory management scheme allows programs to exploit the memory reference pattern of the underlying algorithms, thereby improving utilisation of the system storage resources. This result is illustrated by using significant examples of memory management activities implemented at the application program level. Published online: 8 February 2001     

Making Workflow Change Acceptable

Virtual professional communities are supported by network information systems composed from standard Internet tools. To satisfy the interests of all community members, a user-driven approach to requirements engineering is proposed that produces not only meaningful but also acceptable specifications. This approach is especially suited for workflow systems that support partially structured, evolving work processes. To ensure the acceptability, social norms must guide the specification process. The RENISYS specification method is introduced, which facilitates this process using composition norms as formal representations of social norms. Conceptual graph theory is used to represent four categories of knowledge definitions: type definitions, state definitions, action norms and composition norms. It is shown how the composition norms guide the legitimate user-driven specification process by analysing a case on the development of an electronic law journal.     

Exploring Context-aware Information Push

Despite much interest over recent years in the area of context-aware computing, there are still a number of significant gaps in our understanding of the HCI issues associated with such systems. One particular issue that remains relatively unexplored is how to design around the apparently conflicting goals of adapting to changes in context while at the same time adhering to the principle of predictability. In this paper, we describe our exploration into this issue through two alternative designs of an interactive context-aware tourist guide. One original design was based around information pull, i.e. the emphasis is on the user to decide when context-aware information is presented. Our second design incorporates the notion of information push whereby the actual presentation of context-aware information is triggered by contextual events, e.g. changes in the user’s location or changes to the opening times of attractions. Through the evaluation of these alternative designs we hope to gain a better understanding of the usability implications relating to push vs. pull in both this specific domain and in interactive context-aware systems in general.     

Modelling Off-the-Shelf Information Systems Requirements: An Ontological Approach

Requirements for choosing off-the-shelf information systems (OISR) differ from requirements for development of new information systems in that they do not necessarily provide complete specifications, thus allowing flexibility in matching an existing IS to the stated needs. We present a framework for OISR conceptual models that consists of four essential elements: business processes, business rules, information objects and required system services. We formalise the definitions of these concepts based on an ontological model. The ontology-based OISR model provides a framework to evaluate modelling languages on how appropriate they are for OISR requirements specifications. The evaluation framework is applied to the Object-Process Methodology, and its results are compared with a similar evaluation of ARIS. This comparison demonstrates the effectiveness of the ontological framework for evaluating modelling tools on how well they can guide selection, implementation and integration of purchased software packages.     

An effective admission control mechanism for variable-bit-rate video streams

For admission control in real-time multimedia systems, buffer space, disk bandwidth and network bandwidth must be considered. The CBR-based mechanisms do not use system resources effectively, since media data is usually encoded with VBR compression techniques. We propose an admission control mechanism based on a VBR data model that has a dynamic period length. In our mechanism, the period can be adaptively changed to maximize the performance, considering both disk bandwidth and buffer space. To compare the performance, extensive simulations are conducted on RR, SCAN, and GSS schemes which have the dynamic period length and the static period length.     

A Context/Communication Information Agent

We are developing a Context/Communication Information Agent (CIA), an autonomous software agent that proactively searches for the right information at the right time. Our goal is to design and evaluate a system that leverages what people naturally do, using this knowledge to retrieve information, and presenting it with a minimal cost of disruption to the users. In this paper, we describe the results a low-fidelity prototype performed in a meeting situation, the design space for such an application, and our plans for continued investigation.     

Discovery and Integration of Mobile Communications in Everyday Life

We report on the results of a study in which 19 new mobile telephone users were closely tracked for the first six weeks after service acquisition. Results show that novices tend to rapidly modify their perceptions of social appropriateness around mobile phone use, that actual nature of use frequently differs from initial predictions, and that comprehension of service-based technologies can be problematic. We also describe instances and features of mobile telephony practice. When in use, mobile phones occupy multiple social spaces simultaneously, spaces with norms that sometimes conflict: the physical space of the mobile phone user and the virtual space of the conversation.     

Building Distributed Context-Aware Applications

Context-aware applications gather information from sensors about their users and operating environment. Sensor handling is a complicated issue that makes it hard and time-consuming to develop context-aware applications. This paper shows how dynamic discovery protocols can be employed to deal with the physical distribution of sensors and the need to share sensors between many applications. We report on our experiences from building a position-aware application using the dynamic discovery protocol that is part of the Jini software infrastructure for distributed systems.     

Citywide: Supporting Interactive Digital Experiences Across Physical Space

The Citywide project is exploring ways in which technology can provide people with rich and engaging digital experiences as they move through physical space, including historical experiences, performances and games. This paper describes some initial results and experiences with this project based upon two prototype demonstrators. In the first, we describe an application in which a search party explores an archaeological site, uncovering enacted scenes within the virtual world that are of a historical relevance to their particular physical location. In the second, we describe a museum experience where participants explore an outdoors location, hunting for buried virtual artifacts that they then bring back to a museum for a more detailed study. Our demonstrators employ a varied set of devices, including mobile wireless interfaces for locating hotspots of virtual activity when outdoors, to give different experiences of the virtual world depending upon location, task, available equipment and accuracy of tracking. We conclude by discussing some of the potential advantages of using an underlying shared virtual world to support interactive experiences across extended physical settings.     

New Active Tools for Supporting Narrative Structures

Constructing stories is a type of playing that involves mobilizing the storyteller’s imagination and finding original ways to convey narrative intentions. When a child invents a story, there is a natural interaction with the local environment and the use of various means of expression. We adopted a user-centered approach to design POGO, a playful environment which utilizes the child’s physical environment and sensory modalities. Pogo is a system of active tools that enable children to create stories by connecting physical and virtual environments. By providing children with the possibility of capturing and manipulating images and various media, and combining them in sequential form, Pogo triggered new strategies in the construction of narrative logic, time and space, in the construction of the episodes and in the visual narration. Correspondence to: Fran?oise Decortis, Psychology and Education Sciences Department, University of Liege, 4000 Liege, Belgium. Email:francoise.decortis@ulg.ac.be     

Using 3D Sound to Improve the Effectiveness of the Advanced Driver Assistance Systems

Future generation cars will be characterized by a wide range of Information Technology (IT) services providing safety and infotainment. This makes the car an information intensive environment where the visual channel is overloaded, putting the safety of drivers and passengers in jeopardy. We propose the use of a 3D auditory display to provide information from the Advanced Driver Assistance Systems. This reduces the eye-off-road time, exploiting the human capability to associate sounds with positions in space. Preliminary lab tests reveal the suitability of this approach. The system still has to be carefully tuned and personalized to achieve usability and reliability, but we think that it provides a complementary channel that is specially useful in low visibility conditions.     

Can We Ever Escape from Data Overload? A Cognitive Systems Diagnosis

Data overload is a generic and tremendously difficult problem that has only grown with each new wave of technological capabilities. As a generic and persistent problem, three observations are in need of explanation: Why is data overload so difficult to address? Why has each wave of technology exacerbated, rather than resolved, data overload? How are people, as adaptive responsible agents in context, able to cope with the challenge of data overload? In this paper, first we examine three different characterisations that have been offered to capture the nature of the data overload problem and how they lead to different proposed solutions. As a result, we propose that (a) data overload is difficult because of the context sensitivity problem – meaning lies, not in data, but in relationships of data to interests and expectations and (b) new waves of technology exacerbate data overload when they ignore or try to finesse context sensitivity. The paper then summarises the mechanisms of human perception and cognition that enable people to focus on the relevant subset of the available data despite the fact that what is interesting depends on context. By focusing attention on the root issues that make data overload a difficult problem and on people’s fundamental competence, we have identified a set of constraints that all potential solutions must meet. Notable among these constraints is the idea that organisation precedes selectivity. These constraints point toward regions of the solution space that have been little explored. In order to place data in context, designers need to display data in a conceptual space that depicts the relationships, events and contrasts that are informative in a field of practice.     

Specifying and Analysing System-Level Inter-Component Interfaces

In control systems, the interfaces between software and its embedding environment are a major source of costly errors. For example, Lutz reported that 20–35% of the safety-related errors discovered during integration and system testing of two spacecraft were related to the interfaces between the software and the embedding hardware. Also, the software’s operating environment is likely to change over time, further complicating the issues related to system-level inter-component communication. In this paper we discuss a formal approach to the specification and analysis of inter-component communication using a revised version of RSML (Requirements State Machine Language). The formalism allows rigorous specification of the physical aspects of the inter-component communication and forces encapsulation of communication-related properties in well-defined and easy-to-read interface specifications. This enables us both to analyse a system design to detect incompatibilities between connected components and to use the interface specifications as safety kernels to enforce safety constraints.     

Appearance-based visual learning and object recognition with illumination invariance

This paper describes a method for recognizing partially occluded objects under different levels of illumination brightness by using the eigenspace analysis. In our previous work, we developed the “eigenwindow” method to recognize the partially occluded objects in an assembly task, and demonstrated with sufficient high performance for the industrial use that the method works successfully for multiple objects with specularity under constant illumination. In this paper, we modify the eigenwindow method for recognizing objects under different illumination conditions, as is sometimes the case in manufacturing environments, by using additional color information. In the proposed method, a measured color in the RGB color space is transformed into one in the HSV color space. Then, the hue of the measured color, which is invariant to change in illumination brightness and direction, is used for recognizing multiple objects under different illumination conditions. The proposed method was applied to real images of multiple objects under various illumination conditions, and the objects were recognized and localized successfully.