Rate-distortion optimized tree-structured compression algorithms for piecewise polynomial images Abstract-This paper presents novel coding algorithms based on tree-structured segmentation, which achieve the correct asymptotic rate-distortion (R-D) behavior for a simple class of signals, known as piecewise polynomials, by using an R-D based prune and join scheme. For the one-dimensional case, our scheme is based on binary-tree segmentation of the signal. This scheme approximates the signal segments using polynomial models and utilizes an R-D optimal bit allocation strategy among the different signal segments. The scheme further encodes similar neighbors jointly to achieve the correct exponentially decaying R-D behavior ( ( ) 0 2 ), thus improving over classic wavelet schemes. We also prove that the computational complexity of the scheme is of ( log ). We then show the extension of this scheme to the two-dimensional case using a quadtree. This quadtree-coding scheme also achieves an exponentially decaying R-D behavior, for the polygonal image model composed of a white polygon-shaped object against a uniform black background, with low computational cost of ( log ). Again, the key is an R-D optimized prune and join strategy. Finally, we conclude with numerical results, which show that the proposed quadtree-coding scheme outperforms JPEG2000 by about 1 dB for real images, like cameraman, at low rates of around 0.15 bpp.

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Workflows for quantitative data analysis in the social sciences The background is given as to how statistical analysis is used by quantitative social scientists. Developing statistical analyses requires substantial effort, yet there are important limitations in current practice. This has motivated the authors to create a more systematic and effective methodology with supporting tools. The approach to modelling quantitative data analysis in the social sciences is presented. Analysis scripts are treated abstractly as mathematical functions and concretely as web services. This allows individual scripts to be combined into high-level workflows. A comprehensive set of tools allows workflows to be defined, automatically validated and verified, and automatically implemented. The workflows expose opportunities for parallel execution, can define support for proper fault handling, and can be realised by non-technical users. Services, workflows and datasets can also be readily shared. The approach is illustrated with a realistic case study that analyses occupational position in relation to health. This section introduces the process of statistical analysis as typically carried out in the social sciences, highlights the role of software tools in performing this, and explains the value of workflows as a means of enhancing the capabilities made available to social scientists for analysing quantitative data. It has been seen that current practice in social science research suffers from limitations in how statistical analyses are developed: lack of technical expertise, very limited reuse, restricted public documentation, difficulty in making analyses repeatable by others, lack of high-level workflows, no exploitation of parallel execution, and little integrity checking. Nevertheless the results of statistical analysis in the social sciences can have far-reaching consequences. For example, Government policy on health service provision may be determined by the analysis of a health survey. Consequently it is desirable to improve standards in the analysis of quantitative datasets, particularly with regard to documenting and publishing records of the research.. The work reported in this paper is a response to these issues. The focus has been on effective tools that transfer advanced computing techniques into mainstream social science. It is believed that the objectives for this work in Sect. 1.4 have been addressed. The approach is general, but has been illustrated with statistical analysis scripts in workflows. Reuse of statistical scripts is achieved through shared use of the services created from them, with workflows also being reusable. High-performance computing techniques are used to allow parallel execution where the workflow structure allows it. Formal methods can also be used to check workflows thoroughly prior to deployment and execution.. In the approach presented, statistical analysis scripts are modelled abstractly as mathematical functions and concretely as web services. This permits their composition into high-level workflows using BPEL. The client installation to use workflows is minimal: just a workflow editor like Chive. The client typically communicates with a server, where workflows are generated by Cress and coordinated by ActiveBPEL. Scripts are executed by a designated host or a Condor pool under control of the workflow. The latter improves performance through load sharing and parallel execution.. The Cress notation for statistical analysis workflows has been introduced. This has been illustrated through a realistic case study using actual datasets and statistical scripts supplied by a social scientist. This has demonstrated the viability of the approach. One promising area for future development lies in sharing services and workflows among researchers. This is currently achieved by depositing social science workflows on the Dames server. It is planned to look into how Cress workflows could also be integrated with myExperiment.. Because the approach does not rely on copying the files used by workflows, it can scale up adequately for large datasets. Cress has also been demonstrated on very complex workflows (up to 26 pages of diagrammatic description). However, it would be useful to carry out actual performance measurements with larger datasets and more extended analyses.. Preliminary investigations have looked into using Cress for orchestrating the analyses performed in neuroscience. Here, the building blocks are completely different (programs to analyse empirical data from neural measurements). The suitability of the approach will also be investigated for environmental science workflows, e.g. the analysis of crop data or fishery data. This work is a contribution to data-intensive scientific research. In particular, it offers a workflow-based solution for performing large-scale statistical analysis in a more modular, reusable and efficient way. Computational workflows are not new, but the approach described in the paper offers distinctive advantages. Although scientific workflows have been developed in some disciplines, notably for bioinformatics, their application to quantitative social science is novel. Apart from the preliminary efforts on the NeISS project mentioned in Sect. 2.2, the work presented here on social science workflows is unique as far as the authors are aware.. Some approaches have been designed to pre-populate analytical scripts in quantitative social science applications. For example e-STAT (Sect. 2.1) supports templates in alternative statistical languages. Other approaches have focused on data processing rather than analysis. For example, PanelWhiz (http://www.panelwhiz.eu) prepares data extraction codes for Stata, and the Minnesota Population Center (http:// www.ipums.org) uses a data extraction syntax generator. These cater for specific forms of data processing and analysis, whereas the workflow approach in this article applies much more generically across the many and varied tasks in quantitative social research.. The Cress notation, toolset and methodology used in the work are mature, having been under development for 15 years. However, the specific developments to support statistical workflows are new. The strengths of Cress are as follows:. • The Cress notation is straightforward and easily learned by non-specialists. As noted in Sect. 4.1, the usability of Cress by developers has been successfully demonstrated.. • Cress has demonstrated its flexibility by being used in multiple areas: Intelligent Network, Internet telephony, Interactive Voice Response, Web Services, Grid Services and Device Services.. • Cress eases workflow analysis by providing high-level languages for formal verification and formal validation (Clove and Mustard). Some verification can be performed without any effort by the workflow developer. More specialised verification is possible, and is eased by automatic translation from high-level properties into temporal logic. Formal validation is more pragmatic and based on developer-defined tests. These can also be reused for performance checking.. • The Cress toolset is portable (being written in Perl and Java) and has been run on multiple platforms.. The case studies already conducted using the workflow approach are encouraging evidence that it will be suitable for social scientists and will scale up to larger problems. This section presents related work by others on e-social science and computational workflows. Some general techniques can be adapted to support workflows for quantitative data analysis.

O O B I I O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O B I I


Biomedical ontologies: what part-of is and isn't Mereological relations such as part-of and its inverse has-part are fundamental to the description of the structure of living organisms. Whereas classical mereology focuses on individual entities, mereological relations in biomedical ontologies are generally asserted between classes of individuals. In general, this practice leaves some basic issues unanswered: type constraints of mereological relations, e.g., concerning artifacts and biological entities, the relation between parthood and time, inferred parts and wholes as well as a delimitation of parthood against spatial inclusion. Furthermore, mereological relations can be asserted not only between physical objects but also between biological processes and medical procedures. We analyze these ambiguities and make suggestions for a standardization of mereological relations in biomedical ontologies. It is widely recognized that the construction of biomedical ontologies should obey formal ontological criteria, a necessary condition for interoperability between human and electronic agents. Beside is-a, the class subsumption relation, the mereological relations part-of and its inverse has-part play a pivotal role in all ontologies which describe the structure of biological organisms and their constituents. A wide variety of partonomies are present in the Foundational Model of Anatomy (FMA) [1, 2] , the NCI thesaurus [3] , the anatomy schemata of the GALEN CORE model [4] , the SNOMED CT [5] anatomy branch, the Gene Ontology [6] , and in the diverse ontologies of the Open Biomedical Ontologies (OBO) platform [7] . Several authors [8] [9] [10] grant the relation part-of the status of a foundational relation. This is supported by top-level ontologies such as DOLCE [11] , BFO [12] , and GOL [13] .. It is critical to any effort of ontology engineering in a given domain that relations characterized as foundational are formally grounded and robust with regard to individual interpretations in order to prevent human-dependent semantic bias. This requirement is roughly fulfilled for the well-studied is-a relation [14] . However, it has been shown that matters become more complicated when not arbitrary classes but properties or universals and their changes over time are considered [15] [16] [17] [18] .. In this paper, we concentrate on the mereological relations part-of and has-part. The work on these relations, as far as their assertion between individual entities is concerned, is extensive [19] . In biomedical ontologies, attempts to provide formal foundations for mereological relations are more recent [20, 9, 21, 22] . Here, in contrast to standard mereology, Part-Of and Has-Part denote relations between classes (such as in Part-Of (Cell Nucleus, Cell)) and not relations between individuals, and they consequently have different properties. Moreover, parthood relations between classes are complex and go beyond what has been formalized in standard mereology. Related ontological questions that need to be answered prior to the construction of for-mal bio-medical ontologies generally fall into the following categories:. • Parthood between material and non-material entities: Are left ventricles parts of hearts, and is the boundary of this liver part of this liver? • Parthood over time: Is a lost hair or a surgically removed appendix still part of the body? Is a tissue sample in a laboratory still part of the organism from which it was taken? • Parthood and spatial location: Are transplanted organs part of the donor organism, the receptor organism, or both? Is a given molecule part of the cell in which it is located at a given moment? Is a tooth filling part of a tooth? • Parthood between occurrents: Is the suturing process part of an appendectomy, or is the interphase part of mitosis?. Obviously, such mereological puzzles are concerned with basic classes of biological entities and are, hence, relevant to medicine (e.g., transplanted organs, tissue samples, and heart ventricles) as well as to cell and molecular biology.. The formal treatment of mereological relations in biomedical ontologies is still insufficient. We claim that the specific aspects of partonomic bio-medical structures pointed out above need to be made more explicit. Otherwise, implicit assumptions in the different uses of Part-Of and Has-Part will vary among ontology engineers, users and applications; unintended interpretations may occur, and, as a consequence, system interoperability may be at risk.. In the following, we will first clarify basic ontological categories and then discuss mereological relations between individuals and between classes of individuals. We will, furthermore, address dimensions in which part-of related ambiguities still exist: time-dependent parthood, parthood vs. location, and parts of occurrents. Our proposals focus on the practice of ontology engineering in the biomedical domain. None of these proposals are entirely new. We, therefore, refrain from formal definitions and restrict ourselves to natural language. More detailed formalisms can be found in the literature cited. In this paper, we have shown that the way mereological relations are specified in biomedical ontologies is insufficient. In the common practice of carrying over instancelevel relations to a class-level, ambiguities inherently arise, which, however, can be resolved by introducing clear definitions. Another aspect is taking time into account, both with regard to continuants and occurrents. Here, again, clear definitions are helpful in order to determine what the standard reading of part-of is and is not.. Both on the level of instances and on the level of classes there is a fundamental difference between parthood and (spatial) location. Whereas it is, for various reasons, relatively easy to specify what is meant by Ôa is located in b,Õ it is much more intricate to differentiate it from Ôa is a part of bÕ or Ôa is contained in b.Õ This is particularly the case when relations between changing objects and objects at different levels of granularity are considered. Difficulties also arise when both, biological and non-biological entities, are taken into account.. We presented a methodology that addresses at least some issues raised. This methodology is to consider under which circumstances the fact that a is located in b implies that a is a part of b. We showed that taking into account facts about relative location over time, as well as facts about participation in biological functionalities often provides necessary and sufficient conditions that support valid inferences of facts about parthood from facts about location. Due to this reason we consider located-in as a foundational relation in its own right.. This has practical implications for using ontologies as the backbone of formal reasoning systems. There are typical reasoning patterns which exploit mereotopological characteristics of biological entities, e.g. the propagation of properties, as extensively discussed in [40, 64, 65, 52, 21] . For these purposes, a clear distinction between parthood and containment is fundamental.. The limitations of our approach are mostly due to vague boundaries between kinds, controversial conceptualizations of the lives of biological objects of different types, conflicts between functionality and genetic origin, and an imprecise understanding of biological functionality, for which a well-founded ontological account is still required.

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Evidence of Hypertext in the scholarly archive This paper attempts to substantiate recent observations about the development of hypertext rhetoric in scholarly archives by reporting the results of some simple quantitative studies of the use by researchers of a major scholarly archive. Dalgaard's recent article [3] argues that the part of the Web that constitutes the scientific literature is composed of increasingly linked archives. He describes the move in the online communications of the scientific community towards an expanding zone of second-order textuality, of an evolving network of texts commenting on, citing, classifying, abstracting, listing and revising other texts. In this respect, archives are becoming a network of texts rather than simply a classified collection of texts. He emphasizes the definition of hypertext as multi-linear text, in contrast to the simple definition of a hypertext as 'a document with links in'.. The HEP archive (www.arxiv.org) is one of the pre-eminent examples of a scholarly archive, consisting of the pre-and reprint articles (submitted by the authors) in the area of High Energy Physics. Its user community is technically sophisticated, having been on the 'cutting edge' of web dissemination of research communications (in fact, it was for just this community that the Web was developed), and has long had a culture of sharing prepublication documentation, even before the widespread use of personal computers.. The OpCit project (opcit.eprints.org, funded under the NSF/DLI 2 programme) started as a project to interlink the texts stored in the HEP archive and is now involved in providing more general metatextual services for such archives. As part of its remit, it has been investigating the way in which researchers and users of the archive have been using it to deposit and read new research results, and to try to understand the influence of the archive on the way that scientific publication has been changing over the last decade. The HEP archive is not only a repository of the scholarly literature, it is an embodiment of it and a focus of the process of scholarly communication between researchers. The role of the computer as evidenced in these results is to increase the interactivity of the scholarly process, diminishing the latencies and barriers between reading and writing and enhancing the scholarly community's ability to create a complex, multiplybranched (hyper) text.

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Cerebral Substrates of Musical Imagery Musical imagery refers to the experience of "replaying" music by imagining it inside the head. Whereas visual imagery has been extensively studied, few people have investigated imagery in the auditory domain. This article reviews a program of research that has tried to characterize auditory imagery for music using both behavioral and cognitive neuroscientific tools. I begin by describing some of my behavioral studies of the mental analogues of musical tempo, pitch, and temporal extent. I then describe four studies using three techniques that examine the correspondence of brain involvement in actually perceiving vs. imagining familiar music. These involve one lesion study with epilepsy surgery patients, two positron emission tomography (PET) studies, and one study using transcranial magnetic stimulation (TMS). The studies converge on the importance of the right temporal neocortex and other right-hemisphere structures in the processing of both perceived and imagined nonverbal music. Perceiving and imagining songs that have words also involve structures in the left hemisphere. The supplementary motor area (SMA) is activated during musical imagery; it may mediate rehearsal that involves motor programs, such as imagined humming. Future studies are suggested that would involve imagery of sounds that cannot be produced by the vocal tract to clarify the role of the SMA in auditory imagery. Many people experience the sounds of music in two distinct but related manners. Listening to live or recorded music is, of course, the way we commonly think of enjoying music. However, many people also report that they can reexperience music by imagining it in their heads. This can be pleasurable or not, depending on the circumstances, but in either case, the experience appears to be a vivid one, even among people untrained in music. In fact, I am often asked how to "stop" a tune from obsessively intruding into everyday thoughts. Highly trained musicians report that they can use auditory imagery to help them in their everyday tasks, such as "hearing" music as they read musical notation.. In recent years, I have studied the characteristics of this auditory imagery experience, initially from a behavioral perspective and more recently from a cognitive neuroscientific perspective. I have been most interested in the auditory imagery experiences of untrained or moderately trained musicians, although many interesting questions derive from considering experts as well. My paradigms and experimental logic have been derived partly from the more extensive literature in visual imagery; other approaches have been created anew as the need arose. In studying any mental imagery, the challenge is to externalize what is essentially an internal experience to examine what it means to have, in the case of musical imagery, a "tune inside the head."

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Building a General Purpose Pedagogical Agent in a Web-Based Multimedia Clinical Simulation System for Medical Education Abstract-In medical education, pedagogical agents are widely used by computer learning systems to simulate tutors and/or mimic tutoring interactions, as well as offering just-in-time and adaptive feedback. Although the theoretical aspect of the pedagogical agents has been well-documented in literature, relatively fewer efforts have been made on how a pedagogical agent should be implemented in a real multimedia computerized simulation learning environment. In this paper, we propose a general purpose pedagogical agent architecture and implement it in the multimedia medical simulation Web-based learning system called Health Information Network Teaching System (HINTS) to further facilitate students' learning and thereby make the HINTS a more helpful educational tool. Our focus is the design of the general purpose pedagogical architecture and its implementation in a multimedia computerized simulation learning environment. A preliminary students' performance evaluation result is also reported. We analyzed how to evaluate the students' performance and how the hints were given by the pedagogical agent. The system has been installed in the National Cheng Kung University Medical Center, Tainan, Taiwan for trial purposes. Some experiments have been conducted and the results have shown that the pedagogical agent indeed help the students in their learning process. T HE problem-based learning (PBL) model [1] , [2] , [3] has its roots in the apprenticeship or learning-by-doing method. It emphasizes a "real-world" approach to learning: a student-centered process that is both constructive and collaborative and has been widely used in medical education [4] , [5] . In practice, instructors must not only be experts in their specific knowledge domain, but also be specially trained as guides to entertain, motivate, and provide hints to their students. Therefore, although PBL is a very effective learning method in some cases, it is usually a very labor-intensive and time-consuming process for the instructors. Since the World Wide Web and multimedia technology have attracted a great deal of attention as a vehicle for delivering e-Learning, some medical schools and centers have incorporated multimedia computerized PBL into their clinical training curriculum to make PBL clinical education more efficient [7] , [8] . The theoretical aspect of the multimedia computerized PBL has been studied extensively in [9] , [10] which described it as online authentic learning. Therefore, we will not repeat the details of the theoretical foundation and concepts. However, current multimedia computerized PBL systems still have some drawbacks that may impair the efficiency of the students' learning. For instance, they do not really emulate the traditional PBL clinical education where the teachers can not only entertain, motivate, and provide hints for the students but also diagnose the students' misconceptions and resolve them. Therefore, although multimedia computerized PBL clinical education is more efficient than traditional methods in terms of the labor involved, it may be less effective. However, an agent-assisted, computer-based architecture may be employed as a promising medium for implementing a multimedia computerized PBL environment [11] , [12] , [13] .. We have implemented an interactive multimedia computerized PBL clinical education system called Health Information Network Teaching System (HINTS) [14] . In the HINTS system, students: 1) are puzzled and challenged by the patient's problems; 2) try to interactively get more information needed from the system, such as questioning the patients and ordering various laboratory tests, as well as getting the associated multimedia information from the system, such as Computed Tomography (CT) images and the sound of the patient's heart beats; and 3) work on their ways in an attempt to diagnose and cure the patient's problem. In other words, the HINTS can simulate the stepby-step scenario of a real clinical case in a clinical setting without using 3D virtual reality techniques-the 3D visual effects. The details will be described later on. In other words, the HINTS simulates the clinical setting and enables students to work on the virtual patient to practice their diagnostic thinking processes and skills.. Although the theoretical aspect of the pedagogical agents has been well-documented in literature [15] , [16] , [17] , [18] , less efforts have been made on how a pedagogical agent should be implemented in a real computerized simulation learning environment. We propose and implement here a general purpose pedagogical agent architecture that inhabits the HINTS to further facilitate the students' learning and make the HINTS more effective and efficient for learning. In the domain of learning, "effectiveness" describes the learning outcomes (better grades) whereas "efficiency" is always associated with time (studying faster) [6] . Although our focus is the design of the pedagogical architecture and its implementation, a preliminary students' performance evaluation result is reported. The result shows that the agent can make the learning more efficient. However, a more in-depth evaluation of the effectiveness of the system is still needed in the future. We will follow the same definitions in this paper. In Section 2, we present how the HINTS really works in practice and briefly describes the theoretical backgrounds of the pedagogical agent adopted by HINTS. In Section 3, since the pedagogical agent has to evaluate the student's performance in order to decide how to provide timely hints to the students, we will discuss how the student performance is evaluated in the HINTS. We will also describe how the pedagogical agent works from the students' point of view to facilitate their learning. In Section 4, the architecture of the pedagogical agent and some implementation issues are discussed. In Section 5, we will report the results of our experiments with the system. Finally, we will offer our conclusions in the Section 6.

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