waashk/dblp huggingface dataset:
the syntactic and semantic correctness of pictorial configurations to query geographic databases by pql. in the field of geographic information systems, one important issue is related to define a sound method of syntactic and semantic correctness analysis for queries which can lead to multiple interpretations for the system and for the user. in this paper, we propose an approach in order to determine the exact syntactic and semantic interpretations of geographic configurations that are involved in queries for a pictorial query language. this language, called pql, supports interactive manipulation of geographic elements letting users directly to express a query by drawing. we put in evidence and underline all the syntactically correct pictorial configurations among geographic objects which represent the topological relationships. then, upon such analysis we determine the semantic correctness of configurations depending on the stored geographic data, and the detection of the ambiguities. we propose different solutions to determine the semantic correctness integrating the result of such approach to the set of pql operators. finally, we show the capability of such approach to resolve the ambiguities which arise from the formulation of complex queries involving multiple geographic objects.
design and implementation of component-based adaptive web presentations. engineering adaptive web applications implies the development of content that can be automatically adjusted to varying client devices and user preferences. to meet this requirement, the amacont project recently introduced a component-based xml document format. configurable document components encapsulating adaptive behavior and layout are used on different abstraction levels in order to support flexible reuse for effective web page generation. this paper focuses on the process of designing and implementing such component-based adaptive web presentations. based on the model-driven specification framework from the hera project, different phases of adaptation design are identified and their realization using amacont components is explained. finally, a pipeline-based document generator for dynamically publishing component structures to different web output formats is described.
a modular approach to build structured event-based systems. event-based systems are developed and used as a coordination model to integrate components in loosely coupled systems. research and product development focused so far on efficiency issues but neglected methodological support to build such systems. in this paper, we present the modular design and implementation of an event system which supports scopes and event mappings, two new and powerful structuring methods that facilitate engineering and coordination of components in event-based systems. the approach is based on a trace-based specification method adapted from temporal logic.
verification of coordinated exception handling. an important challenge faced by the developers of fault-tolerant distributed systems is to build fault tolerance mechanisms that are reliable. to achieve the desired levels of reliability, the development of mechanisms for detecting and handling errors should be rigorous or formal. in this paper, we present an approach to modeling and verifying fault-tolerant distributed systems that use exception handling as the main fault tolerance mechanism. the proposed approach is based on a formal model for specifying the structure of a system in terms of cooperating participants that handle exceptions in a coordinated manner. we use a medical control system as a case study to validate the proposed approach.
an extensible architecture-based framework for coordination languages. the dynamic and heterogeneous nature of distributed systems make the development of distributed applications a difficult task. various tools, such as middleware systems, component systems, and coordination languages, offer support to the application developer at different levels.there are several coordination systems that integrate such tools into a complete environment to build applications from heterogeneous components. to achieve extensibility they usually have a layered architecture: an application is first mapped to a middle layer and then to a target system. but this approach hides the specific features of a target system from the developer, as they are not represented in the middle layer, and often induces additional run-time overhead.in this paper we introduce the extensible coordination framework ecf that allows developers to build efficient distributed applications which exploit the specific features of the target systems. support for target systems and application domains are encapsulated by extension modules. modules can be built on top of other modules to support refined functionality.
automated terrain generation using lidar and waterbody survey data. lidar data provides a dense and precise sampling of ground elevations on land, but not of bathymetric elevations in a waterway. by supplementing lidar data with densely interpolated waterway survey data, terrain models can be generated to approximate lidar-derived topography combined with waterway bathymetry. three-dimensional interpolation techniques are used to generate a dense waterway bathymetry, as well as the bounding region to clip and fill the lidar data with this bathymetry. consequently, the resulting terrain is fit for both visualization and further processing in hydraulic and hydrological models.
reflection-based implementation of java extensions: the double-dispatch use-case. reflection-based libraries could sometimes be used to extend the expressive power of java without modifying the language nor the virtual machine. in this paper, we present the advantages of this approach together with general guidelines allowing such implementations to be practicable. then, we show how these principles have been applied to implement an efficient and general double-dispatch solution for java.
a content classification and filtering server for the internet. the amazing growth of the web in recent years, which includes content inappropriate for some classes of users, has gone hand in hand with increasingly sophisticated mobile access devices (e.g., cell phones). in this context, a major challenge is the dynamic adaptation of content, which allows these devices to access any given content independently of its original format, allied to a number of added value services such as virus scanning, language translation and content filtering. this article proposes and implements a content classification and filtering server inserted into a content adaptation architecture based on the internet content adaptation protocol (icap). the proposed solution does not depend on hardware or software characteristics of access devices, for the service is done externally through edge devices (e.g., proxies).
from modeling to enactment of distributed workflows: an agent-based approach. this paper proposes an agent-based approach which seamlessly supports the phases of modeling and enactment of distributed workflows. an agent-based distributed workflow model is basically obtained by instantiating a mas (multi-agent system) meta-model for the management of distributed workflows by means of a workflow schema based on the workflow patterns. in order to enact an obtained agent-based model, a jade-based workflow enactment framework, directly designed upon the mas meta-model, was developed.
multi-coordination of mobile agents: a model and a component-based architecture. this paper proposes a model along with a reference software architecture enabling multi-coordination between distributed and mobile software agents. multi-coordination allows agents to choose among a variety of different coordination spaces and patterns which best fit their dynamic communication and synchronization needs. it can be fruitfully exploited by agents in heterogeneous and dynamic environments like the internet where the mutable conditions of communications and computing usually affect both the currently agreed workflow and the performances of agent-based applications. the proposed model centers on high-level events which can be locally emitted and/or received by agents and which unify access to and exploitation of underlying coordination spaces and agent server resources. the model is supported by a component-based architecture which provides agent management and notably agent coordination through a coordination context dynamically assembled with a set of different local and/or global coordination spaces. a prototypical implementation of the architecture was also carried out using java and the voyager orb middlewares.
lemp: lightweight efficient multicast protocol for video on demand. in this paper, we propose a new scalable application-layer protocol, specifically designed for data streaming applications with large client sets. this is based upon a control hierarchy of successive levels for the clients, has minimal overhead with constant number of messages per client, and is robust to client and network failures, making it suitable for wireless environments. the video server bandwidth utilization is also significantly reduced. we present an analysis and simulation results, showing that lemp is near optimum in terms of performance.
visualization of neuronal fiber connections from dt-mri with global optimization. diffusion tensor mri (dt-mri) provides valuable 3d data describing diffusion characteristics of water molecules in the human brain. from dt-mri, it is hoped that neuronal fiber connections among cortical regions can be reliably extracted and adequately interpreted. to achieve this goal, several significant challenges persist. in this paper, by means of dynamic programming we have developed a global fiber reconstruction algorithm enabling efficient visualization of neuronal connections queried by both the start and end points on the fly. besides an inherent ability to handle noisy datasets, our algorithm also naturally addresses situations where neuronal fibers branch or cross each other. we demonstrate the efficacy of our approach with visualization of neuronal connections among activated brain cortical regions detected by functional mri (fmri).
time-varying, multivariate volume data reduction. large-scale supercomputing is revolutionizing the way science is conducted. a growing challenge, however, is understanding the massive quantities of data produced by large-scale simulations. the data, typically time-varying, multivariate, and volumetric, can occupy from hundreds of gigabytes to several terabytes of storage space. transferring and processing volume data of such sizes is prohibitively expensive and resource intensive. although it may not be possible to entirely alleviate these problems, data compression should be considered as part of a viable solution, especially when the primary means of data analysis is volume rendering. in this paper we present our study of multivariate compression, which exploits correlations among related variables, for volume rendering. two configurations for multidimensional compression based on vector quantization are examined. we emphasize quality reconstruction and interactive rendering, which leads us to a solution using graphics hardware to perform on-the-fly decompression during rendering.
methods for learning classifier combinations: no clear winner. this work compares two approaches to finding effective topic-independent classifier combinations. we suggest a new federated approach and compare it against the global approach. our results indicate that the relative effectiveness of these approaches depends on the measure used to evaluate them. we suggest explanations for these results.
authenticity in a reliable protocol for mobile computing. we consider a known protocol for reliable multicast in distributed mobile systems where mobile hosts communicate with a wired infrastructure by means of wireless technology. the original specification of the protocol does not take into consideration any notion of computer security: an adversary may eavesdrop on communications between hosts and inject packets over the wireless links. we suggest a secured version of the protocol providing authenticity and integrity of packets over the wireless links. the secure mechanisms introduced rely on two different techniques: secure wireless channels and 1-time signature schemes. further, we outline the formal verification of part of the secured protocol.
echo-cardiography on the web: design and set-up of a virtual community of experts. nowadays digital ultrasound-cardiovascular devices are able to send out directly digital images and films (still and loop modes). thanks to the large adoption of such devices, the echocardiographic world is facing new ways of exchanging images and collaborate. what we present in this paper is a digital echo-lab system composed by a web site, supporting and coordinating the work of specialists and a teleconsulting desktop application for second opinion (carolin), designed around echo-cardiography needs. the web solution is suitable for echocardiography because stored loops have dimensions, which are compatible (in terms of mbytes) with present internet bandwidth limitations. the web site is integrated with a largely adopted peer-2-peer telemedicine teleconsultation tool (carolin) allowing it to act as a bridge between carolin's world and on-line web information sharing (suitable for students or virtual communities). we will also discuss the modeling process adopted to catch real users' needs: in most cases users do not have clear visions of how such technologies could improve their work and also developers do not know details of physicians work, that is why we need a precise modeling process.
node splitting algorithms in tree-structured high-dimensional indexes for similarity search. content-based searches and retrievals in multimedia and image databases use high-dimensional indexing structures for organizing the features of the objects. most of those index structures are tree-structured whose nodes have a limit on the number of entries describing the subtrees rooted at those nodes. when index trees are built by repeated insertion of entries, nodes need to be split and the tree balanced accordingly. node-splitting algorithms eventually determine the final structure of the tree which will have a profound effect on the search performance. this paper presents a comparative study of several node splitting algorithms for a typical high-dimensional indexing structure. the algorithms are implemented and tested on an image database and the results are presented.
response order rearrangement on a caching proxy for reducing www latency. recently, the explosive growth of the www (world wide web) has been causing serious performance degradation on the internet. one of the approaches of addressing this problem is the use of proxy caching, where a proxy cache is placed close to a set of clients and delivers web content to them faster than the origin server. on the other hand, the ability of http/1.1 (hypertext transfer protocol) has been enhanced by the introduction of pipelined requests, which allow a client to make multiple requests without waiting for each response. however, previous research on proxy caching has not fully investigated the impact of pipelined requests. in this paper, we propose 'http-ror (http with response order rearrangement)', a new approach toward reducing the user-perceived latency, and consider pipelined requests to caching proxies. we then show analytical performance evaluations and practical evaluations in several experimental environments.
towards system software for physical space applications. in ubiquitous computing era, the notion of context-awareness will play an important role. an application should be aware of its operating context for supporting and enriching human activities. such contextual information is required to be captured as seamlessly as possible through interaction between users and surrounding environments. this leads to the need for dealing with a wide variety of contextual information from a physical world.in this paper, we propose a conceptual framework, bazaar, for modeling the physical world and for manipulating the model. it constructs the model with self-descriptive objects represented as a set of triples. also, a programming model allows a developer to intuitively manipulate the model and develop an application. moreover, we report experiences with building sample applications.
"take me with you!": a case study of context-aware application integrating cyber and physical spaces. context-awareness is one of the exciting research topics in a ubiquitous computing environment, which is expected to create some new business and/or services by using sensors and actuators. especially, context information from cyber space allows a system to extend its information space both temporalily and spatially. however, many applications do not regard context information from cyber space as a information source of future tense. this keeps applications from being aware of a wide variety of context.we have developed a system software "contextdistillery", which enables an application developer to obtain context information incrementally without taking account of descriptive information, meta-context information. next, we have built an application "take me with you!", which exemplifies the notion of physical/cyber space integration.this paper reports a case study of the application development. discussions of findings through the application development are presented. moreover, an architecture for realizing more practical notions of context-awareness is introduced based on the discussions.
hierarchical binary histograms for summarizing multi-dimensional data. the need to compress data into synopses of summarized information often arises in many application scenarios, where the aim is to retrieve aggregate data efficiently, possibly trading off the computational efficiency with the accuracy of the estimation. a widely used approach for summarizing multi-dimensional data is the histogram-based representation scheme, which consists in partitioning the data domain into a number of blocks (called buckets), and then storing summary information for each block. in this paper, a new histogram-based summarization technique which is very effective for multi-dimensional data is proposed. this technique exploits a multi-resolution organization of summary data, on which an efficient physical representation model is defined. the adoption of this representation model (based on a hierarchical organization of the buckets) enables some storage space to be saved w.r.t. traditional histograms, which can be invested to obtain finer grain blocks, thus approximating data with more detail. experimental results show that our technique yields higher accuracy in retrieving aggregate information from the histogram w.r.t. traditional approaches (classical multi-dimensional histograms as well as other types of summarization technique).
an adaptive three-dimensional dct compression based on motion analysis. in this paper, we propose an adaptive 3d-dct compression technique, which dynamically determines an optimal size of the video cube based on the motion analysis. the technique consists of two steps: (a) it analyses the motion within a small (16x16) video cube of eight successive frames, and (b) it selects the size of the cube based on the motion analysis and applies the 3d-dct algorithm on the selected video cube. the effectiveness of the proposed technique is illustrated by implementing it to a number of video sequences with low, medium, and high motion.
a framework for resource-aware knowledge discovery in data streams: a holistic approach with its application to clustering. mining data streams is a field of increase interest due to the importance of its applications and dissemination of data stream generators. most of the streaming techniques developed so far have not addressed the need of resource-aware computing in data stream analysis. the fact that streaming information is often generated or received onboard resource-constrained computational devices such as sensors and mobile devices motivates the need for resource-awareness in data stream processing systems. in this paper, we propose a generic framework that enables resource-awareness in streaming computation using algorithm granularity settings in order to change the resource consumption patterns periodically. this generic framework is applied to a novel threshold-based micro-clustering algorithm to test its validity and feasibility. we have termed this algorithm as ra-cluster. ra-custer is the first stream clustering algorithm that can adapt to the changing availability of different resources. the experimental results showed the applicability of the framework and the algorithm in terms of resource-awareness and accuracy.
hardware/software 2d-3d backprojection on a sopc platform. the reduction of image reconstruction time is needed to spread the use of pet for research and routine clinical practice. in this purpose, this article presents a hardware/software architecture for the acceleration of 3d backprojection based upon an efficient 2d backprojection. this architecture has been designed in order to provide a high level of parallelism thanks to an efficient management of the memory accesses which would have been otherwise strongly slowed by the external memory. the reconstruction system is embedded in a sopc platform (system on programmable chip), the new generation of reconfigurable circuit. the originality of this architecture comes from the design of a 2d adaptative and predictive cache (2d-ap cache) which has proved to be an efficient way to overcome the memory access bottleneck. thanks to a hierarchical use of this cache, several backprojection operators can run in parallel, accelerating in this manner noteworthy the reconstruction process. this 2d reconstruction system will next be used to speed up 3d image reconstruction.
a functional architecture for self-aware routers. in this paper, we first present the concept of self-configuration and self-provisioning applied into the scope of the ip routers. a global view of the concepts which are addressed in this document is given, considering the automation level of the operations, and their communication schemes. the node characteristics that are taken into account in the definition of self-configuration and self-provisioning mechanisms are also detailed, introducing the second part of the paper. in this part, a reference architecture for a self-configuration router is given, allowing the community to have a common understanding on the expected functionalities by such routers. an evaluation of the existing proposals to address part of all the issues raised by self-configuration is also presented.
using xml to implement abstraction for model checking. model checking has become one of the most powerful methods for automatic verification of software systems. however it is widely accepted that this technique is only usable when the behavior of the system to be analyzed is given by small models, in order to avoid the state explosion problem. the paper presents &alpha;spin, an xml-based tool for obtaining abstract versions from a given model written in promela, which can be verified with the model checker spin. this tool follows the theoretical basis presented in [9].