Showing papers in "Journal of the Brazilian Computer Society in 2005"

Systems of exchange values as tools for multi-agent organizations

Abstract: This paper introduces systems of exchange values as tools for the organization of multi-agent systems. Systems of exchange values are defined on the basis of the theory of social exchanges, developed by Piaget and Homans. A model of social organization is proposed, where social relations are construed as social exchanges and exchange values are put into use in the support of the continuity of the performance of social exchanges. The dynamics of social organizations is formulated in terms of the regulation of exchanges of values, so that social equilibrium is connected to the continuity of the interactions. The concept of supervisor of social equilibrium is introduced as a centralized mechanism for solving the problem of the equilibrium of the organization The equilibrium supervisor solves such problem making use of a qualitative Markov Decision Process that uses numerical intervals for the representation of exchange values.

Putting “Cartography” into the History of Cartography: Arthur H. Robinson, David Woodward, and the Creation of a Discipline

Abstract: Arthur Robinson and David Woodward significantly expanded the scope and nature of the history of cartography. Previously, cartographic historians had emphasized the study of map content. As practicing cartographers, Robinson and Woodward promoted the “internal” study of the history of cartographic techniques and design. Robinson used an historically minded rhetoric to define the proper nature of U.S. academic cartography after 1945 and he pursued important studies in the history of thematic mapping. Woodward pioneered the study of map printing. Moreover, he was crucial in transforming the “internal” approach to cartographic history into a discrete discipline focused on the study of maps as human documents. Woodward’s humanistic perspective ultimately formed the foundation of both the multi-volume History of Cartography and Brian Harley’s cartographic theorizing.

Attention on Maps

Abstract: Wilson’s (1998) notion of consilience among disciplines should be a goal for cartographers. Consilience requires important facts and fact-based theories to apply across disciplines. This paper reviews research on visual attention as an example of a topic shared by information science disciplines. Attention is considered as a competition between neural processes that allow information to be selected and emphasized for perceptual processing. Visual attention has been modeled as a spotlight, zoom lens, gradient, and multiple spotlights. It is argued that visual attention can impact multiple map reading processes and that cartographers can use knowledge about the effects of attention on map reading to design more effective maps. Attention can be directed to locations, objects, and features in the visual field and impacts performance on a variety of map reading tasks. Important general questions relating visual attention and map reading are stated and the literature providing answers discussed. The “dark side” of attention is also discussed and linked to the concepts of inhibition of return, visual marking, inattentional blindness, change blindness, and the attentional blink. Specific map-reading processes affected by visual attention are considered that include figure-ground segregation, visual search, and object selection and grouping. Research trends related to cartographic design and map reading are considered for these processes. Future cartographic studies are considered in four categories—vision before attention, vision with attention, vision after attention, and vision without attention. Understanding the role of visual attention in map reading should be a goal of cartographers interested in producing effective maps.

Ontology Issues and Applications Guest Editors’ Introduction

Abstract: Fred Freitas Centro de Informatica Universidade Federal de Pernambuco Caixa Postal 7851 Cidade Universitaria 50732-970 Recife, PE, Brazil fred@cin.ufpe.br Heiner Stuckenschmidt Department of Mathematics and Computer Science Vrije Universiteit Amsterdam De Boelelaan 1081a 1081 HV Amsterdam, The Netherlands heiner@cs.vu.nl Natalya F. Noy Stanford Medical Informatics 251 Campus Drive Stanford, CA 94305-5479, USA noy@stanford.edu

An information retrieval application using ontologies

Abstract: Searching for information in long videos can be a time-consuming experience. In this paper, we describe OnAIR, an ontology-aided information retrieval system applied to retrieve clips from video collections. We used a video collection compiled from interviews with Ana Teixeira, a Brazilian artist. The interviews were made by Paula P. Braga, the domain expert. The interview is developed in the domain of contemporary art and the system uses a domain ontology to expand the queries with related terms. We tested the system with a battery of queries, and we veri.ed that the ontology contributes to the e.ciency improvement in terms of the relevance of retrieved documents. We designed the system to work in a domain-independent way, allowing us to move to other domains by just changing the underlying ontologies and video collections.

Mapping the Miasma: Air, Health, and Place in Early Medical Mapping

Abstract: Medical mapping is broadly assumed to have been a nineteenth century reaction both to the appearance of cholera and the social consciousness of principally British reformers. It is however older, more embedded in the scientific enterprise than the social critique, and in the end, more central to both than researchers typically recognize. This paper argues that medical mapping was from its start in the late 1600s principally a tool for the self-conscious testing of spatial propositions, arguing a relationship between health and place, and between the locus of specific disease incidence and suspected sites of local infectious generation. Through the nineteenth century the resulting work--social and medical— typically advanced a miasmatic theory that argued that infectious diseases were generated spontaneously and diffused naturally through the air. This paper reviews the history of medical cartography as a scientific enterprise in the age of miasma, and the importance of this work to social reformers as an outcome rather than a principal impetus to mapping as a critical tool.

Analyzing requirements of knowledge management systems with the support of agent organizations

Abstract: Knowledge Management (KM) is considered by many organizations a key aspect in sustaining competitive advantage. Designing appropriate KM processes and enabling technology face considerable risks, as they must be shaped to respond to specific needs of the organizational environment. Thus, many systems are abandoned or fall into disuse because of inadequate understanding of the organizational context. This motivates current research, which tends to propose agent organizations as a useful paradigm for KM systems engineering. Following these approaches, organizations are analyzed as collective systems, composed of several agents, each of them autonomously producing and managing their own local data according to their own logic, needs, and interpretative schema, i.e. their goals and beliefs. These agents interact and coordinate for goal achievement defining a coherent local knowledge system. This paper presents a novel methodology for analyzing the requirements of a KM system based on an iterative workflow where a pivotal role is played by agent-oriented modeling. Within this approach, the needs for KM systems are traced back to the organization stakeholders’ goals. A case study is used to illustrate the methodology. The relationship of this work with current studies in agent organizations and organizational knowledge management is also discussed. Differently from other works, this methodology aims at offering a practical guideline to the analyst, pointing out the appropriate abstractions to be used in the different phases of the analysis.

Agents organizations : a concise overview

Abstract: Agent organizations are an emergent area of multi-agent systems (MAS) that relies on the notion of openness and heterogeneity of MAS and poses new demands on traditional MAS models. These demands include the integration of organizational and individual perspectives and the dynamic adaptation of models to organizational and environmental changes.

Using a functional ontology of reputation to interoperate different agent reputation models

Abstract: This paper presents a Functional Ontology of Reputation that could be used as a common shared reputation knowledge by agents. Although there is a huge work on agent reputation, each research defines its own basic concepts. Sometimes different meanings are associated to the same term and in other occasions the same meaning is related to different terms. We claim that the reputation knowledge structured as an ontology could be used to enable the semantic integration level involved in the interoperation of software agents using different reputation models. We have illustrated this idea by showing a semantic mapping for the reputation concepts used in three distinct reputation models. That mapping shows how this ontology could act as a common global ontology that supports the semantic integration among these models.

DBM-Tree: trading height-balancing for performance in metric access methods

Abstract: Metric Access Methods (MAM) are employed to accelerate the processing of similarity queries, such as the range and the k-nearest neighbor queries. Current methods, such as the Slim-tree and the M-tree, improve the query performance minimizing the number of disk accesses, keeping a constant height of the structures stored on disks (height-balanced trees). However, the overlapping between their nodes has a very high influence on their performance. This paper presents a new dynamic MAM called theDBM-tree (Density-Based Metric tree), which can minimize the overlap between high-density nodes by relaxing the height-balancing of the structure. Thus, the height of the tree is larger in denser regions, in order to keep a tradeoff between breadth-searching and depth-searching. An underpinning for cost estimation on tree structures is their height, so we show a non-height dependable cost model that can be applied for DBM-tree. Moreover, an optimization algorithm calledShrink is also presented, which improves the performance of an already builtDBM-tree by reorganizing the elements among their nodes. Experiments performed over both synthetic and real world datasets showed that theDBM-tree is, in average, 50% faster than traditional MAM and reduces the number of distance calculations by up to 72% and disk accesses by up to 66%. After performing the Shrink algorithm, the performance improves up to 40% regarding the number of disk accesses for range andk-nearest neighbor queries. In addition, theDBM-tree scales up well, exhibiting linear performance with growing number of elements in the database.

The use of an enterprise ontology to support knowledge management in software development environments

Abstract: Software engineering is knowledge-intensive activity and knowledge is thought to be the most important asset in an organization. Therefore this paper presents an approach to support Knowledge Management in Software Development Environments that is strongly based on ontologies: Enterprise Oriented Software Development Environments. After describing the components of such environments, this paper focuses on the Enterprise Ontology and on three tools developed based on this ontology: a ‘yellow pages’ tool which shows the distribution of competencies in the organization, a tool to support the allocation of people to software projects and a graphic tool for representing and visualizing organizational processes.

Elements of Cartography: Tracing Fifty Years of Academic Cartography

Abstract: When Arthur Robinson published the first edition of Elements of Cartography in 1953, it marked a major change in academic cartography. Erwin Raisz’s General Cartography, first published in 1938 and revised in 1948, had been the standard text. Robinson’s book represented the metamorphosis in cartography after WWII and set the standard for the second half of the twentieth century. A review of the book’s contents through its 6 editions reveals the prevalent thinking in cartography during a dynamic period in the history of cartography. Through it we can trace changes from hand-drawn maps to the rise of GIS and remote sensing. Although Elements is no longer the major textbook, its impact was enormous. This paper traces the history of late twentieth century cartography through the pages of Elements of Cartography. A content analysis of all six editions of Elements of Cartography was done to determine the emphasis on various aspects of cartography. An analysis of Erwin Raisz’s two editions of General Cartography was also included in order to note the changes in content and philosophy from pre-war to post-war cartography.

Automatic formation and analysis of multi-agent virtual organization

Abstract: Virtual organization refers to the temporary teaming of enterprises. By sharing physical, human and knowledge resources via information technologies, a virtual organization enables member enterprises to share skills, costs, access to one another’s markets and, at the same time decrease the risk of investments. To realize this new generation of business model, the ability to form and operate virtual enterprise is very important. The paper describes our experience gained by implementing a multiagent system that simulates an artificial marketplace, for which we have derived several decision-making mechanisms in various stages of a virtual organization. We presented a negotiation protocol and a bid selection algorithm for agents to form a virtual organization. We adopted the Motivational Quantities framework to support the agent’s local reasoning process. In order to better understand the organizational problem, we adapted a statistical model that predicts the expected rewards of individual agents and the performance of the virtual organization. The comparison and analysis of the results from both the simulation and the model prediction are also presented in this paper.

Analyzing, modeling and predicting organizational effects in a distribuited sensor network

Abstract: The organizational design of a distributed system defines how entities act and interact to achieve local and global objectives. We describe how a system employing different types of organizational techniques has been used to address the challenges posed by a distributed sensor network environment. The high-level, multi-agent architecture of this realworld system is given in detail, and we provide empirical results demonstrating the effects the organization has on the system’s performance across several different metrics. As with any design, the particular approach that is employed makes trade-offs, some of which are obvious and some more subtle. The presence of such trade-offs motivates the need for a better understanding of precisely how the organization influences large and small-scale behaviors. To address this need, we first demonstrate how a collection of analytic models can be developed to predict such effects. This experience is then used to ground the presentation of a more comprehensive, domain-independent organizational modeling language called ODML. The structure and capabilities of ODML are explained through the construction of a unified model of our sensor network organization. We then show that this model provides an accurate prediction of the original empirical results.

Using AOP to bring a project back in shape: the ourgrid case

Abstract: The design and development of distributed software is a complex task. This was not different in OurGrid, a project whose objective was to develop a free-to-join grid. After two years of development, it was necessary to redesign OurGrid in order to cope with the integration problems that emerged. This paper reports our experience in using Aspect-Oriented Programming (AOP) in the process of redesigning the OurGrid middleware. The essential direction of our approach was to get the project (and the software) back in shape. We discuss how the lack of separation of concerns created difficulties in the project design and development and how AOP has been introduced to overcome these problems. In particular, we present the event-based pattern designed to better isolate the middleware concerns and the threads. Besides, we also present the aspects designed for managing the threads and for aiding the testing of multithreaded code. We also highlight the lessons learned in the process of regaining control of the software.

The weighted gradient: a color image gradient applied to morphological segmentation

Abstract: This paper proposes a method for color gradient computation applied to morphological segmentation of color images. The weighted gradient (with weights estimated automatically), proposed in this paper, applied in conjunction with the watershed from markers technique, provides excelent segmentation results, according to a subjective visual criterion. The weighted gradient is computed by linear combination of the gradients from each band of an image under the IHS color space model. The weights to each gradient are estimated by a systematic method that computes the similarity between the image to compute the gradient and an ”ideal image”, whose histogram has an uniform distribution. Several experiments were done in order to compare the segmentation results provided by the weighted gradient to the results provided by other color space metrics, also according to a subjective criterion, and such comparison is present in this paper.

A new approach for regularized image interpolation

Abstract: This paper presents a non-iterative regularized inverse solution to the image interpolation problem. This solution is based on the segmentation of the image to be interpolated into overlapping blocks and the interpolation of each block, separately. The purpose of the overlapping blocks is to avoid edge effects. A global regularization parameter is used in interpolating each block. In this solution, a single matrix inversion process of moderate dimensions is required in the whole interpolation process. Thus, it avoids the large computational cost due to the matrices of large dimensions involved in the interpolation process. The performance of this approach is compared to the standard iterative regularized interpolation scheme and to polynomial based interpolation schemes such as the bicubic and cubic spline techniques. A comparison of the suggested approach with some algorithms implemented in the commercial ACDSee software has been performend in the paper. The obtained results reveal that the suggested solution has a better performance as compared to other algorithms from the MSE and the edges preservation points of view. Its computation time is relatively large as compared to traditional algorithms but this is acceptable when image quality is the main concern.

Ecolingua: a Formal ontology for data in ecology

Abstract: Ecolingua is an ontology for ecological quantitative data, which has been designed through reuse of a conceptualisation of quantities and their physical dimensions provided by theEngMath family of ontologies. A hierarchy of ecological quantity classes is presented together with their definition axioms in first-order logic. An implementation-level application of the ontology is discussed, by way of which conceptual ecological models are synthesised from data annotations inEcolingua through reuse of existing model structures.

Looking Closer: A Guide to Making Bird’s-eye Views of National Park Service Cultural and Historical Sites

Abstract: The US National Park Service (NPS) has long used large-scale panoramas, also known as bird’s-eye views, to portray park sites where buildings and other human-made features are plentiful. This paper examines these bird’s-eye views, most of which were produced by nationally renowned contract illustrators in a wide range of artistic styles. Both their traditional and digital work receive attention. A brief historical review looks at the antecedents of current NPS products dating back to the Renaissance. The practical second half of the paper focuses on how the NPS now designs these bird’s-eye views with 3D software, with an eye toward cost savings. Topics include viewing parameters in a 3D scene, preparingDEMs, modeling buildings, designing trees, and creating environmental special effects. Two dozen full-color illustrations supplement the text.

A swarm based approach to adapt the structural dimension of agents' organizations

Abstract: One of the well studied issues in multi-agent systems is the standard action-selection problem where a goal task can be performed in different ways, by different agents. Also the sequence of these actions can influence the goal achievement or its quality. This class of problems has been tackled under different approaches. At the high-level coordination one, the specification of the organizational issues is crucial. However, in dynamic environments, agents must be able to adapt to the changing organizational goals, available resources, their relationships to the presence of another agents, and so on. This problem is a key one in multi-agent systems and relates to models of learning and adaptation, such as those observed among social insects. The present paper tackles the process of generating, adapting, and changing multi-agent organization dynamically at system runtime, using a swarm inspired approach. This approach is used here mainly for task allocation with low need of pre-planning and specification, and no need of explicit coordination. The results of our approach and another quantitative one are compared here and it is shown that in dynamic domains, the agents adapt to changes in the organization, just as social insects do.

On the design of ontology-driven workflow flexibilization mechanisms

Abstract: Workflow management systems usually interpret a workflow definition rigidly. However, there are real life situations where users should be allowed to deviate from the prescribed static workflow definition for various reasons, including lack of information and unavailability of the required resources. To flexibilize workflow execution, this paper first proposes mechanisms that allow execution to proceed in the presence of incomplete information, by adopting presuppositions, and in the presence of negative information, by suggesting execution alternatives. Then, the paper presents an architecture for a workflow system, driven by ontologies that capture semantic relationships between workflows and resources. The architecture includes a component which uses matching techniques to find alternatives for workflows and resources.

Large-scale Topographic Web Maps Using Scalable Vector Graphics

Abstract: With the advent of the Internet, particularly the World Wide Web, the use and demand for online maps has grown very rapidly. Large scale topographic maps from the United States Geological Survey (USGS) at a scale of 1:24,000 have been traditionally distributed in paper form. To make these maps available to a larger number of people, rasterized versions are now available from various sources. Instead of the common raster format presentation, the solution presented here is based on a vector approach using Scalable Vector Graphics (SVG), a relatively new vector format describing vector graphics for the Web. SVG provides many advantages compared to the use of a raster-based presentation, such as the quality of the graphical representation, maintenance, actualization, interactivity, and extensibility through other Web programming languages. The purpose of this research is to propose an optimal and logical structure for a SVG document with a minimal file size that would be universally applicable to all USGS large scale topographic maps while maintaining the graphic quality at a comparable level with maps presented on paper. The study shows that SVG is a promising technology for delivering high quality, fully-vector topographic maps via the Internet, both in terms of graphic quality and interactivity.

A Lua-based AOP Infrastructure

Abstract: In this paper we describe an aspect-oriented infrastructure to handle dynamic AOP based on the Lua language. This infrastructure is composed of AspectLua, a Lua extension that allows the declaration of aspects, and a meta-object protocol, LuaMOP, that unifies the introspective and reflective mechanisms provided by Lua. Aspects are defined in isolation using AspectLua and then they are weaved through LuaMOP. An important feature of AspectLua is to allow the association of aspects with undeclared elements of the application code (anticipated join points). Furthermore, it combines a range of features to make AOP easier and powerful.

Miscommunicating With Isoline Preference Maps: Design Principles for Thematic Maps

Abstract: Gould and White (1968) introduced the measurement and isoline mapping of regional preferences, producing preference or “isoeutope” maps. As cartographers know, the decision to employ isoline mapping as a cartographic display technique is valid insofar as certain assumptions are met, notably the assumption that the variable being mapped reflects an underlying continuum. This assumption is doubtful in the case of a variable such as regional preference insofar as it is based on rankings or ratings of existing regional units such as states for which human cognition is not continuous. The implications of mapping preference with isolines are discussed, particularly with respect to the attitudes the maps reflect and the cognitive responses they elicit in viewers. We argue that isoline mapping of data such as state preferences produces misleading impressions of intraregional variation and is neither necessary nor desirable. Alternative methods for the collection and cartographic display of regional preference data are discussed. Notably, we propose the use of “psuedo-Chernoff” faces as an appropriate technique.

From Drawer to Digital: A Statewide Collaboration for Building Digital Historic Map Collections

Abstract: Nowadays, when you tell someone you recently visited a map library, it’s hard for them to discern whether you mean virtually or in person. The two comprehensive public universities in Nevada are building complementary digital collections of historic maps of interest to the region to enable virtual map library visits. This article briefly describes the two university library map collections, discusses the criteria that were used to select maps to be digitized, provides insight into some of the scanning issues and how they were resolved, discusses technical considerations in using CONTENTdm®, and talks about metadata issues in the collaborative effort. The conclusion provides insight into what has been learned and why the project is important as a foundation for the future.

Unusual Displays of DEMs

Abstract: Three procedures for producing new ways to visualize landforms as maps or images derived from Digital Elevation Models (DEMs) are given. One procedure is used to create a highly detailed circular gray scale image from an azimuthal distribution. A second procedure utilizes the principles associated with x-ray tomography for the construction of a volumetric map from DEM cross-sectional ‘slices’. The conversion of a DEM to a Digital Distance Model (DDM) comprises the third procedure, to provide ‘side-looking’ views of the DEM in a variety of map formats including stereograms. DEMs generated from Mars Orbital Laser Altimeter (MOLA) data were used to produce illustrations utilizing the three procedures.