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1.
How do we measure and improve the quality of a hierarchical ontology?   总被引:1,自引:0,他引:1  
Hierarchical ontologies enable organising information in a human-machine understandable form, but constructing them for reuse and maintainability remains difficult. Often supporting tools available lack formal methodological underpinning and their developers are not supported by any concomitant metrics. The paper presents a formal underpinning to provide quality metrics of a taxonomy hierarchical ontology and proposes a methodology for semi-automatic building of maintainable taxonomies. Users provide terms to be used to describe different ontological elements as well as their attributes and their ranges of values. The methodology uses the formalised metrics to assess the quality of the users input and proposes changes according to given quality constraints. The paper illustrates the metrics and the methodology in constructing and repairing two medium size well-known taxonomies.  相似文献   

2.
We analyze the convergence of quasi-Newton methods in exact and finite precision arithmetic using three different techniques. We derive an upper bound for the stagnation level and we show that any sufficiently exact quasi-Newton method will converge quadratically until stagnation. In the absence of sufficient accuracy, we are likely to retain rapid linear convergence. We confirm our analysis by computing square roots and solving bond constraint equations in the context of molecular dynamics. In particular, we apply both a symmetric variant and Forsgren's variant of the simplified Newton method. This work has implications for the implementation of quasi-Newton methods regardless of the scale of the calculation or the machine.  相似文献   

3.
The amendment of patent law of India in 2005 to fulfill her international obligation under the TRIPS Agreement (World Trade Organization Agreement on Trade Related Intellectual Property Rights) was an outcome of an attempt to balance the competing interests of several stakeholders, including indigenous pharmaceutical companies, multi-national pharmaceutical companies, non-governmental organizations and civil society groups concerned with access to affordable drugs. The adverse consequence of this delicate balancing is introduction of some provisions in the Act whose compatibility with the TRIPS Agreement is questionable, and which therefore are prone to litigations. Section 107A(b) of the amended patent law dealing with parallel imports is one such provision, which, if interpreted word for word could have significant connotations for the rights of a patent owner. This article aims to examine the inconsistencies intrinsic in Section 107A(b) and discusses the divergences in the Indian patent law associated with the doctrine of exhaustion and parallel imports. This article also proposes legal amendments with a view to eliminate inconsistencies intrinsic in the section and enlarge the ambit of the exhaustion principle conceptualized therein, while concurrently remaining compliant with the TRIPS Agreement.  相似文献   

4.
The problem of automated visual surveillance has spawned a lively research area, with 2005 seeing three conferences or workshops and special issues of two major journals devoted to the topic. These alone are responsible for somewhere in the region of 240 papers and posters on automated visual surveillance before we begin to count those presented in more general fora. Many of these systems and algorithms perform one small sub-part of the surveillance task, such as motion detection. But even with low level image processing tasks it is often difficult to compare systems on the basis of published results alone. This review paper aims to answer the difficult question “How close are we to developing surveillance related systems which are really useful?” The first section of this paper considers the question of surveillance in the real world: installations, systems and practises. The main body of the paper then considers existing computer vision techniques with an emphasis on higher level processes such as behaviour modelling and event detection. We conclude with a review of the evaluative mechanisms that have grown from within the computer vision community in an attempt to provide some form of robust evaluation and cross-system comparability.  相似文献   

5.
Toffoli  Tommaso 《Natural computing》2019,18(3):489-512
Natural Computing - Hadn’t this question already been answered? We all know about computation-universal Turing Machines. And we know that any such machine can simulate a space–time...  相似文献   

6.
The utilization of the results of control theory in the process control field has been lagging behind other application fields such as aerospace by many years. It is argued that the availability of high capacity computing at low price will change this situation and that new powerful control techniques can now be implemented in process control.  相似文献   

7.
Knowledge and Information Systems - Existing well-investigated Predictive Process Monitoring techniques typically construct a predictive model based on past process executions and then use this...  相似文献   

8.
Many crop models use the NRCS Curve Number method to estimate runoff, but the simplified assumptions of this method are rarely considered in model uncertainty assessments. The associated uncertainty may be high for cropping systems with a significant part of bare soil like vineyards, specifically under a Mediterranean climate. In this work, we evaluate for a vineyard crop model the structure uncertainty coming from its uncertain runoff module. We introduce a new method based on additional knowledge about the runoff process and on a mathematical property of the model structure. Situations characterized in terms of soil water content and mean runoff conditions are studied for two applications of the vineyard model and guidelines for model users are derived. This work shows that uncertainty quantification can benefit from the knowledge of mathematical properties of a model and provide clear guidelines to model users.  相似文献   

9.
This paper is an in-depth study of qualitative physical reasoning about one particular scenario: using a box to carry a collection of objects from one place to another. Specifically we consider the plan, plan1 “Load objects uCargo into box oBox one by one; carry oBox from location l1 to location l2”. We present qualitative constraints on the shape, starting position, and material properties of uCargo and oBox and on the characteristics of the motion that suffice to make it virtually certain that plan1 can be successfully executed. We develop a theory, consisting mostly of first-order statements together with two default rules, that supports an inference of the form “If conditions XYZ hold, and the agent attempts to carry out plan1 then presumably he will succeed”. Our theory is elaboration tolerant in the sense that carrying out the analogous inference for carrying objects in boxes with lids, in boxes with small holes, or on trays can reuse much of the same knowledge. The theory integrates reasoning about continuous time, Euclidean space, commonsense dynamics of solid objects, and semantics of partially specified plans.  相似文献   

10.
Abstract

A Vigenère cipher applies a single short key repeatedly to encrypt a plaintext. If a cryptanalyst correctly finds out the key length, the ciphertext can be divided into multiple instances of shift cipher and be broken by frequency analysis. To determine the key length, the twist algorithm, an alternate method to the standard Kasiski and Friedman tests, was recently proposed. In this article, we propose the twist+ algorithm, an improved twist algorithm, which can estimate the key length more accurately than the original twist algorithm.  相似文献   

11.
In many practical problems, we must optimize a set function, i.e., find a set A for which f(A)→max, where f is a function defined on the class of sets. Such problems appear in design, in image processing, in game theory, etc. Most optimization problems can be solved (or at least simplified) by using the fact that small deviations from an optimal solution can only decrease the value of the objective function; as a result, some derivative must be equal to 0. This approach has been successfully used, e.g., for set functions in which the desired set A is a shape, i.e., a smooth (or piece-wise smooth) surface. In some real-life problems, in particular, in the territorial division problem, the existing methods are not directly applicable. For such problems, we design a new simple differential formalism for optimizing set functions. ©1999 John Wiley & Sons, Inc.  相似文献   

12.

User participation in the design process may be an axiom of quality design but in the design of interactive, innovative computer systems, user participation may be neither feasible nor desirable. Here, user centred methodologies miss the point. If computers are a medium rather than a tool, then we need a new design paradigm that recognizes the difference between using a product and experiencing a show. In this paper the role of users in interactive systems design within the context of Multimedia product development is discussed. The main features of Multimedia product development are outlined through reference to an empirical study of two organizations and the role of users in the design process is discussed. Finally a different design paradigm is suggested.  相似文献   

13.
Personalization is a strategic tool for product or service differentiation, especially when competition is keen in the market. Many personalization strategies have been developed and realized with this in mind. Little is known about the impact of different personalization strategies, regarding different personalization dimensions on customer retention, however. This has resulted in a lack of consensus on how best to design personalization strategies. To address the related issues, this study identifies the dimensions of personalization, and investigates the effect of each dimension on customer retention. It does so by implementing actual personalization systems corresponding to two factorial design experiments involving 372 participants. Multiple analysis of covariance reveals the effectiveness of each dimension and interactions among them. This study consequently proposes the optimal combination of personalization dimensions that leads to customer satisfaction and loyalty.  相似文献   

14.
The design of the database is crucial to the process of designing almost any Information System (IS) and involves two clearly identifiable key concepts: schema and data model, the latter allowing us to define the former. Nevertheless, the term model is commonly applied indistinctly to both, the confusion arising from the fact that in Software Engineering (SE), unlike in formal or empirical sciences, the notion of model has a double meaning of which we are not always aware. If we take our idea of model directly from empirical sciences, then the schema of a database would actually be a model, whereas the data model would be a set of tools allowing us to define such a schema.The present paper discusses the meaning of model in the area of Software Engineering from a philosophical point of view, an important topic for the confusion arising directly affects other debates where model is a key concept. We would also suggest that the need for a philosophical discussion on the concept of data model is a further argument in favour of institutionalizing a new area of knowledge, which could be called: Philosophy of Engineering.  相似文献   

15.
Some of our recent observations suggest that mental rotation may be important for reduction of motion sickness in microgravity as well as in the microgravity simulator. Therefore, we suggest that development of the ability to perform mental rotation may be important for adaptation to many virtual environments. Training virtual environment operators to perform mental rotation may enhance operator performance both by increasing their ability to "locomote in" and manipulate that environment and by reducing motion sickness associated with transitions between virtual and normal environments.  相似文献   

16.
In general terms, Social Presence is a feeling of togetherness regardless of spatial or temporal separation. It is a socioemotional attitude that reflexively centres on other people, via perceptions of their affective attitudes towards oneself. Communication technologies contribute to the maintenance of close personal relationships by facilitating welcome and timely socioemotional presence in the mind of an absent other. Presence of this kind may be ‘in the moment’ of communication and also persist over time, as it is ‘topped up’ through repeated interactions. In this paper, we consider how type of personal relationship and degree of physical separation might condition the Social Presence value of a range of media. We report ratings of Closeness and Social Presence that were gathered over 21 days by 64 participants about the close personal relationships that were meaningful to them. We contrast the communication media they chose to use across four relationship types and whether separations were in the same or in a different city. Our findings are used to discuss new ways of thinking about the connection between people who care about one another, and the meaning of the void that separates them, through the time course of Social Presence and Closeness experiences.  相似文献   

17.
The aim of this study was to explore how human factors were taken into account in the development of a new type of drilling equipment. This study is part of a larger project on the understanding of human factors in the design and implementation of automated drilling technology. The principal study was a longitudinal study lasting 4 years that involved 43 interviews, offshore and onshore observations, and two surveys. The analysis in this paper is based on seven informants who were either part of the design team or the paramount project team developing new automated drilling technology for an offshore oil- and gas-producing installation in the same development project, in addition to project documents. The informants were interviewed using semi-structured interviews, and grounded theory based on the coding process of Strauss and Corbin (Basics of qualitative research: grounded theory procedures and techniques. Sage, Newbury Park, 1990) was used to analyse the data. The core category was found to be insufficient human factor analyses performed in the development phase due to the two main categories, namely (1) insufficient information coordination and (2) narrow focus in different phases of the project. This was found to contribute to increased costs, low user-friendliness, and end users’ insufficient knowledge of safe usage and potential risks. Our conclusion was that homogenous top competence involving technical aspects contributed to developers’ lack of understanding of the need for sufficient analyses of end user requirements and of the tasks that would be affected by the new technology. Hence, we argue that technological development could benefit from including human factors experts from the project’s outset to bridge the gap between the lack of relevant information and sufficient information on which to base development decisions. In addition, we contend that performing human factors analyses throughout the development of a project would be beneficial due to the potential of hindering cultural aspects such as a non-questioning culture, which is viewed as a hazard in high-risk organizations.  相似文献   

18.
We explore one aspect of the structure of a codified legal system at the national level using a new type of representation to understand the strong or weak dependencies between the various fields of law. In Part I of this study, we analyze the graph associated with the network in which each French legal code is a vertex and an edge is produced between two vertices when a code cites another code at least one time. We show that this network distinguishes from many other real networks from a high density, giving it a particular structure that we call concentrated world and that differentiates a national legal system (as considered with a resolution at the code level) from small-world graphs identified in many social networks. Our analysis then shows that a few communities (groups of highly wired vertices) of codes covering large domains of regulation are structuring the whole system. Indeed we mainly find a central group of influent codes, a group of codes related to social issues and a group of codes dealing with territories and natural resources. The study of this codified legal system is also of interest in the field of the analysis of real networks. In particular we examine the impact of the high density on the structural characteristics of the graph and on the ways communities are searched for. Finally we provide an original visualization of this graph on an hemicyle-like plot, this representation being based on a statistical reduction of dissimilarity measures between vertices. In Part II (a following paper) we show how the consideration of the weights attributed to each edge in the network in proportion to the number of citations between two vertices (codes) allows deepening the analysis of the French legal system.  相似文献   

19.
The current interfaces of smart TVs (STVs) lack an effective customization that is consistent with the needs of older adults. Accordingly, this study investigates the usability problems encountered by older adults when using STVs, and it identifies solutions to the most frequent problem. In the pilot study, a usability test was conducted and the difficulty of focus manipulation was found to be the most frequent one. Then in the main study, an experiment was conducted to evaluate two solutions (i.e., maintaining consistent element size and adding arrow hints), which involved remote control (RC) and touchscreen interaction (TI) input methods. Fifty-three older adults were recruited to participate in the study and thus four findings were found. First, the task completion time for manipulating focus increases with age and it rapidly increases after 75 years of age. Second, using a simplified RC can significantly improve the task effectiveness and decrease the number of keystrokes and the completion time for manipulating focus when compared with TI. While when using TI, after adding arrow hints to the STV interface the task completion time and the number of keystrokes are reduced. Third, for both input methods, when the interface comprises elements with inconsistent sizes, adding arrow hints was observed to enhance the task effectiveness and shorten the task completion time. However, the arrow hints were counterproductive when the element sizes were consistent. Fourth, the majority of elderly participants preferred to use arrow hints in the STV interface.  相似文献   

20.
It is now widely recognized that Sendmail, the most widely used UNIX mailer, has certain security gaps, many of which are discovered and reported on a daily basis by researchers and users. One such researcher is Wietse Venema. Venema is a programmer and inventor of numerous irreplaceable tools for UNIX administrators. Examples include SATAN (created together with the equally well known researcher, Dan Farmer) and TCPWrappers, of note recently for allegedly having been illicitly distributed with a Trojan horse inside by a group of malicious hackers. For some time now, Venema has been pointing out to the scientific community just why Sendmail will never be completely secure. Naturally, criticism of a product should be accompanied by suggestions — or better yet — alternatives. Thus, Venema, during his time with the T.J. Watson research laboratories, was driven to launch the Postfix project (a.k.a. Vmailer or Secure Mailer) under the auspices of IBM. As Venema says, there is a dual objective: to give the user an alternate Mail Transfer Agent (MTA) to Sendmail while creating a secure mailer like the well-known Qmail, another program in this category, created by Dan Bernstein.  相似文献   

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