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English to Chinese: link data General field: Tech/Engineering Detailed field: IT (Information Technology)
Source text - English Introduction
The World Wide Web has radically altered the way we share knowledge by lowering the barrier to publishing and accessing documents as part of a global information space. Hypertext links allow users to traverse this information space using Web browsers, while search engines index the documents and analyse the structure of links between them to infer potential relevance to users' search queries (Brin & Page, 1998). This functionality has been enabled by the generic, open and extensible nature of the Web (Jacobs & Walsh, 2004), which is also seen as a key feature in the Web's unconstrained growth.
Despite the inarguable benefits the Web provides, until recently the same principles that enabled the Web of documents to flourish have not been applied to data. Traditionally, data published on the Web has been made available as raw dumps in formats such as CSV or XML, or marked up as HTML tables, sacrificing much of its structure and semantics. In the conventional hypertext Web, the nature of the relationship between two linked documents is implicit, as the data format, i.e. HTML, is not sufficiently expressive to enable individual entities described in a particular document to be connected by typed links to related entities.
However, in recent years the Web has evolved from a global information space of linked documents to one where both documents and data are linked. Underpinning this evolution is a set of best practices for publishing and connecting structured data on the Web known as Linked Data. The adoption of the Linked Data best practices has lead to the extension of the Web with a global data space connecting data from diverse domains such as people, companies, books, scientific publications, films, music, television and radio programmes, genes, proteins, drugs and clinical trials, online communities, statistical and scientific data, and reviews. This Web of Data enables new types of applications. There are generic Linked Data browsers which allow users to start browsing in one data source and then navigate along links into related data sources. There are Linked Data search engines that crawl the Web of Data by following links between data sources and provide expressive query capabilities over aggregated data, similar to how a local database is queried today. The Web of Data also opens up new possibilities for domain-specific applications. Unlike Web 2.0 mashups which work against a fixed set of data sources, Linked Data applications operate on top of an unbound, global data space. This enables them to deliver more complete answers as new data sources appear on the Web.
The remainder of this paper is structured as follows. In Section 2 we provide an overview of the key features of Linked Data. Section 3 describes the activities and outputs of the Linking Open Data project, a community effort to apply the Linked Data principles to data published under open licenses. The state of the art in publishing Linked Data is reviewed in Section 4, while section 5 gives an overview of Linked Data applications. Section 6 compares Linked Data to other technologies for publishing structured data on the Web,before we discuss ongoing research challenges in Section 7.
English to Chinese: Stereoscopy General field: Tech/Engineering Detailed field: Photography/Imaging (& Graphic Arts)
Source text - English Stereoscopy, or the creation and display of stereo images, has its own technology and vocabulary, so there are a few concepts and terms that you need to become familiar with. Normal photography has one camera, or eye, to record a scene that produces a single “flat” picture (Figure 5-34). Stereoscopy uses two cameras to capture two views of the scene at slightly different angles to produce a stereo pair of images (Figure 5-35). If the stereo pair is projected in such a way as to present these slightly different views to each eye, the illusion of depth will be introduced into the picture.
Parallax refers to how different the two views are. If an object is close to the viewer, the differences will be greater (more parallax), and if an object is far away, the differences will be less (less parallax). Another thing that affects parallax is the interpupillary distance (IPD) marked in Figure 5-35. For humans, this is the distance between our two pupils (2.5 inches for the average adult), and for stereo cameras, it is the distance between the centers of their lenses. Increasing the interpupillary distance also increases the parallax.
Disparity is the measure of the pixel offset for an object between the left and right views. Figure 5-36 illustrates how the disparity changes as an object starts in front of the screen and then moves behind it. It also shows how the eyes change convergence with the apparent depth of the object. The left example has the object in front of the screen and exhibits a lot of disparity with the red view shifted to the right. The right example shows the object behind the screen and the red view is now shifted to the left. Note that the middle example shows the object at the screen depth and has no disparity at all.
Translation - Chinese 立体摄像，即立体图像的拍摄和放映。目前已经出现了关于立体摄像的专有技术和词汇, 也就是说你需要熟悉一些相关概念和术语。在通常的摄影过程中，需要有一台摄像机，或者“人眼”，去记录下产生单张平面图像的场景（如图5-34）。而在立体摄像中，需要用到两台摄像机，从两个略有不同的视角进行拍摄，分别摄下两幅立体图像（如图5-35）。如果立体图像对通过略有不同的视角被放映出来，传递给左右眼，那么将会使人眼产生一种图像有“深度”的错觉。