A SIMD parallel trapezoid rasterization algorithm

An algorithm for the rasterization of trapezoids on the Connection Machine^TM (CM) is described. The input consists of an array of trapezoids, with two horizontal sides, arranged with one trapezoid per processor. (Unless otherwise indicated, “processor” should be taken to mean virtual processor.) Each trapezoid is converted to an edge record and the edge records are then distributed to enough processors so that each processor is responsible for one scanline of one trapezoid. Each processor computes a scan record for its scanline, and the scan records are then distributed to enough processors so that one processor is responsible for a single pixel. Final interpolation of position, and possibly shading information, is performed in parallel for all pixels thus created, and the pixels are then broadcast into a frame buffer array, with depth comparisons being performed at the receiving end to ensure that the nearest pixel appears in the array. The Connection Machine-specific features used by the algorithm are logarithmic time cumulative summing, general communication with comparisons for collision arbitration, and virtual processor sets. Performance is similar to that of good graphics workstations. The intended application is to display data already resident in the machine as the result of some previous computation, when a high-performance graphics workstation is not available.     

Configurable multi-perspective business process models

A configurable process model provides a consolidated view of a family of business processes. It promotes the reuse of proven practices by providing analysts with a generic modeling artifact from which to derive individual process models. Unfortunately, the scope of existing notations for configurable process modeling is restricted, thus hindering their applicability. Specifically, these notations focus on capturing tasks and control-flow dependencies, neglecting equally important ingredients of business processes such as data and resources. This research fills this gap by proposing a configurable process modeling notation incorporating features for capturing resources, data and physical objects involved in the performance of tasks. The proposal has been implemented in a toolset that assists analysts during the configuration phase and guarantees the correctness of the resulting process models. The approach has been validated by means of a case study from the film industry.     

Time prediction on multi-perspective declarative business processes

Process-aware information systems (PAISs) are increasingly used to provide flexible support for business processes. The support given through a PAIS is greatly enhanced when it is able to provide accurate time predictions which is typically a very challenging task. Predictions should be (1) multi-dimensional and (2) not based on a single process instance. Furthermore, the prediction system should be able to (3) adapt to changing circumstances and (4) deal with multi-perspective declarative languages (e.g., models which consider time, resource, data and control flow perspectives). In this work, a novel approach for generating time predictions considering the aforementioned characteristics is proposed. For this, first, a multi-perspective constraint-based language is used to model the scenario. Thereafter, an optimized enactment plan (representing a potential execution alternative) is generated from such a model considering the current execution state of the process instances. Finally, predictions are performed by evaluating a desired function over this enactment plan. To evaluate the applicability of our approach in practical settings we apply it to a real process scenario. Despite the high complexity of the considered problems, results indicate that our approach produces a satisfactory number of good predictions in a reasonable time.     

Language-independent look-ahead for checking multi-perspective declarative process models

Software and Systems Modeling - Declarative process modelling languages focus on describing a process by restrictions over the behaviour, which must be satisfied throughout the whole process...     

A multi-perspective knowledge-based system for customer service management

The e-business arena is a dynamic, complex and demanding environment. It is essential to make optimal reuse of knowledge of customer services across various functional units of the enterprise. On the other hand, it is also important to ensure that the customer service staff can access and be trained up with dynamically updated knowledge that meets the changing business environment of an enterprise in customer services. However, conventional way of customer service management (CSM) is inadequate to achieve the multi-perspective of an enterprise for achieving knowledge acquisition, knowledge diffusion, business automation and business performance measurement so as to drive the continuous improvement of the customer service quality. In this paper, a multi-perspective knowledge-based system (MPKBS) is proposed for CSM. The MPKBS incorporates various artificial intelligence technologies such as case-based reasoning (CBR) and adaptive time-series model which are used for decision analysis, performance measurement and monitoring. A prototype customer service portal has been built based on the MPKBS and implemented successfully in a consultancy business.     

基于UML & SystemC的GPU几何管线光栅化硬件建模

架构与算法是决定GPU性能的重要因素,需要尽可能早地对其进行评估和验证。提出基于统一建模语言(Unified Modeling Language, UML)的模型,详述了针对GPU几何管线架构和线图元光栅化算法建模的过程及方法,并采用SystemC语言实现了事务级建模(Transaction-level Modeling,TLM)模型和仿真。验证了架构和算法的正确性以及模型的有效性和可行性,为RTL设计提供了参考依据。     

RiskM: A multi-perspective modeling method for IT risk assessment

Stakeholder involvement and participation are widely recognized as being key success factors for IT risk assessment. A particular challenge facing current IT risk assessment methods is to provide accessible abstractions on matters of IT risk that attend to both managerial and technical perspectives of the stakeholders involved. In this paper, we investigate whether a conceptual modeling method can address essential requirements in the IT risk assessment domain, and which structural and procedural features such a method entails. The research follows a design research process in which we describe a research artifact, and evaluate it to assess whether it meets the intended goals. In the paper, we specify requirements and assumptions underlying the method construction, discuss the structural specification of the method and its design rationale, present a prototypical application scenario, and provide an initial method evaluation. The results indicate that multi-perspective modeling methods satisfy requirements specific to the IT risk assessment domain, and that such methods, in fact, provide abstractions on matters of IT risk accessible to both a technical and a managerial audience.     

基于多层次多角度分析的网络安全态势感知

精确描述网络系统的安全态势是当前网络安全研究的热点,目前对网络系统安全性的理解和预测,大多进行的是定性方面的分析,并且由于出发点、目的等的不同,很难得到一个让各方都满意的结果。本文在准确感知网络系统安全性相关数据的基础上,提出包括网络安全态势专题评估、要素评估和整体评估的多层次多角度评估模型来对网络系统安全性进行评估,保证了评估结果准确、客观和全面。     

A participative end-user method for multi-perspective business process elicitation and improvement

A business process can be characterized by multiple perspectives (intentional, organizational, operational, functional, interactional, informational, etc). Business process modeling must allow different stakeholders to analyze and represent process models according to these different perspectives. This representation is traditionally built using classical data acquisition methods together with a process representation language such as BPMN or UML. These techniques and specialized languages can easily become hard, complex and time consuming. In this paper, we propose ISEA, a participative end-user modeling approach that allows the stakeholders in a business process to collaborate together in a simple way to communicate and improve the business process elicitation in an accurate and understandable manner. Our approach covers the organizational perspective of business processes, exploits the information compiled during the elicitation of the organizational perspective and touches lightly an interactional perspective allowing users to create customized interface sketches to test the user interface navigability and the coherence within the processes. Thus, ISEA can be seen as a participative end-user modeling approach for business process elicitation and improvement.     

Multi-spectral and multi-perspective video arrays for driver body tracking and activity analysis

This paper presents a novel approach to recognizing driver activities using a multi-perspective (i.e., four camera views) multi-modal (i.e., thermal infrared and color) video-based system for robust and real-time tracking of important body parts. The multi-perspective characteristics of the system provides redundant trajectories of the body parts, while the multi-modal characteristics of the system provides robustness and reliability of feature detection and tracking. The combination of a deterministic activity grammar (called ‘operation-triplet’) and a Hidden Markov model-based classifier provides semantic-level analysis of human activity. The application context for this research is that of intelligent vehicles and driver assistance systems. Experimental results in real-world street driving demonstrate effectiveness of the proposed system.     

Components of a multi-perspective modeling method for designing and managing IT security systems

Information technology (IT) security design and management are a major concern and substantial challenge for IT management. Today’s highly complex business and technological environments and the need to effectively communicate and justify IT security requirements and controls demand methodical support. The modeling method presented in this paper addresses this demand. The method is based on the assumption that enriched enterprise models integrating technological, business, organizational and strategic aspects provide an effective foundation for developing and managing IT security systems and facilitating communication and understanding between stakeholders. The proposed modeling method for designing and managing IT security in organizations accounts for different perspectives and is based on multi-perspective enterprise modeling. The core components of the method, based on analysis of requirements at different levels of abstraction, are: modeling language concepts specifically designed to address security issues, process models that guide the use of the resulting language, and a modeling environment. The method facilitates elaborate representations of the various aspects of IT security at different levels of abstraction and covers the entire lifecycle of IT security systems. It not only supports multi-perspective requirement analysis and design but also enables monitoring and analysis of IT security at runtime. The presented artifact is evaluated with recourse to a research method that enables the configuration of multi-criteria justification procedures.     

LAMP: 3D layered, adaptive-resolution, and multi-perspective panorama—a new scene representation

A compact visual representation, called the 3D layered, adaptive-resolution, and multi-perspective panorama (LAMP), is proposed for representing large-scale 3D scenes with large variations of depths and obvious occlusions. Two kinds of 3D LAMP representations are proposed: the relief-like LAMP and the image-based LAMP. Both types of LAMPs concisely represent almost all the information from a long image sequence. Methods to construct LAMP representations from video sequences with dominant translation are provided. The relief-like LAMP is basically a single extended multi-perspective panoramic view image. Each pixel has a pair of texture and depth values, but each pixel may also have multiple pairs of texture-depth values to represent occlusion in layers, in addition to adaptive resolution changing with depth. The image-based LAMP, on the other hand, consists of a set of multi-perspective layers, each of which has a pair of 2D texture and depth maps, but with adaptive time-sampling scales depending on depths of scene points. Several examples of 3D LAMP construction for real image sequences are given. The 3D LAMP is a concise and powerful representation for image-based rendering.     

Towards communityware

This paper summarizes our recent activities to support people to communicate with each other using public computer network systems. Unlike conventional teleconferencing systems, which are mainly for business meetings, we focus on informal communication in open orgnizations. So far, three different systems have been developed and actually tested.

走进数字图书馆

本文针对数字图书馆的概念,特征及数字图书馆的业务工作和对馆员的知识结构要求等问题进行了探讨。同时阐述了建设中国数字图书馆对社会产生积极影响。     

Towards coalgebraic behaviourism

In this paper we show that it is possible to model observable behaviour of coalgebras independently from their internal dynamics, but within the general framework of representing behaviour by a map into a “final” coalgebra.In the first part of the paper we characterise Set-endofunctors F with the property that bisimilarity of elements of F-coalgebras coincides with having the same observable behaviour. We show that such functors have the final coalgebra of a rather simple nature, and preserve some weak pullbacks. We also show that this is the case if and only if F-bisimilarity corresponds to logical equivalence in the finitary fragment of the coalgebraic logic.In the second part of the paper, we present a construction of a “final” coalgebra that captures the observable behaviour of F-coalgebras. We keep the word “final” quoted since the object we are going to construct need not belong to the original category. The construction is carried out for arbitrary Set-endofunctor F, throughout the construction we remain in Set, but the price to pay is the introduction of new morphisms. The paper concludes with a hint to a possible application to modelling weak bisimilarity for coalgebras.     

Towards language-to-language transformation

This paper proposes a simplicity-oriented approach and framework for language-to-language transformation of, in particular, graphical languages. Key to simplicity is the decomposition of the transformation specification into sub-rule systems that separately specify purpose-specific aspects. We illustrate this approach by employing a variation of Plotkin’s Structural Operational Semantics (SOS) for pattern-based transformations of typed graphs in order to address the aspect ‘computation’ in a graph rewriting fashion. Key to our approach are two generalizations of Plotkin’s structural rules: the use of graph patterns as the matching concept in the rules, and the introduction of node and edge types. Types do not only allow one to easily distinguish between different kinds of dependencies, like control, data, and priority, but may also be used to define a hierarchical layering structure. The resulting Type-based Structural Operational Semantics (TSOS) supports a well-structured and intuitive specification and realization of semantically involved language-to-language transformations adequate for the generation of purpose-specific views or input formats for certain tools, like, e.g., model checkers. A comparison with the general-purpose transformation frameworks ATL and Groove, illustrates along the educational setting of our graphical WebStory language that TSOS provides quite a flexible format for the definition of a family of purpose-specific transformation languages that are easy to use and come with clear guarantees.

     

Towards Pseudonymous e-Commerce

The lack of privacy is one of the main reasons that limits trust in e-commerce. Current e-commerce practice enforces a customer to disclose her identity to the e-shop and the use of credit cards makes it straightforward for an e-shop to know the real identity of its customers. Although there are some payment systems based on untraceable tokens, they are not as widely used as credit cards. Furthermore, even without buying anything, a customer is already disclosing some information about who or where she may be by just connecting to the e-shop's web server and leaving behind an IP-address. In this paper, we present novel components that enable secure pseudonymous e-commerce. On the one hand, these components allow a customer to browse through an e-shop, select goods, and pay the goods with her credit card such that neither the e-shop operator nor the credit card issuer nor an eavesdropper is able to get any information about the customer's identity. On the other hand, it is guaranteed that none of the involved parties is able to act dishonestly during the credit card payment. Such a system could greatly enhance trust in e-commerce since it overcomes the customers' privacy concerns.     

Towards systolizing compilation

Summary A scheme for the compilation of imperative or functional programs into systolic programs is demonstrated on matrix composition/decomposition and Gauss-Jordan elimination. Using this scheme, programs for the processor network Warp and for several transputer networks have been generated. Christian Lengauer holds a Dipl. Math. (1976) from the Free University of Berlin, and an M.Sc (1978) and Ph.D. (1982) in Computer Science from the University of Toronto. He was an Assistant Professor of Computer Sciences at The University of Texas at Austin from 1982 to 1989 and is presently a Lecturer in Computer Science at the University of Edinburgh. His past research has been in the areas of systolic design, formal semantics and program construction, and automated theorem proving. Michael Barnett received a B.A. in Computer Science from Brooklyn College/City University of New York in 1985, and is currently a Ph.d. candidate at the University of Texas at Austin, where he has been since 1986. From 1985 to 1986 he worked at IBM's T.J. Watson Research Center. His current research interests include formal methods, programming methodology, and functional programming. Duncan G. Hudson III received the B.A. degree in computer sciences from The University of Texas at Austin in 1987 and the M.S.C.S. degree in computer sciences from The University of Texas at Austin in 1989. He has worked as a Graduate Research Assistant at The University of Texas at Austin in the areas of graphical parallel programming environments, parallel numerical algorithms, and objectoriented programming languages for parallel architectures and as a Software Design Engineer at Texas Instruments in the areas of objectoriented databases and parallel image understanding. He is currently a Ph.D. candidate in the Department of Computer Sciences at The University of Texas at Austin. His current research interests include parallel architectures and algorithms and parallelizing compilers.This research was supported in part by the following funding agencies: through Carnegie-Mellon University by the Defense Advanced Research Projects Agency monitored by the Space and Naval Warfare Systems Command under Contract N00039-87-C-0251 and by the Office of Naval Research under Contracts N00014-87-K-0385 and N00014-87-K-0533; through Oxford University by the Science and Engineering Research Council under Contract GR/E 63902; through the University of Texas at Austin by the Office of Naval Research under Contract N00014-86-K-0763 and by the National Science Foundation under Contract DCR-8610427