LOC Workshop on Etexts, Library of Congress [books to read in a lifetime TXT] 📗

said, the issue of reuse (how much one can take apart and reuse in other applications) was not being well considered. He also raised the issue of active versus passive use, one aspect of which is how much information will be manipulated locally by users. Most people, he argued, may do a little browsing and then will wish to print. LYNCH was uncertain how these resources would be used by the vast majority of users in the network environment.

LYNCH next said a few words about X-Windows as a way of differentiating between network access and networked information. A number of the applications demonstrated at the Workshop could be rewritten to use X across the network, so that one could run them from any X-capable device- -a workstation, an X terminal—and transact with a database across the network. Although this opens up access a little, assuming one has enough network to handle it, it does not provide an interface to develop a program that conveniently integrates information from multiple databases. X is a viewing technology that has limits. In a real sense, it is just a graphical version of remote log-in across the network. X-type applications represent only one step in the progression towards real access.

LYNCH next discussed barriers to the distribution of networked multimedia information. The heart of the problem is a lack of standards to provide the ability for computers to talk to each other, retrieve information, and shuffle it around fairly casually. At the moment, little progress is being made on standards for networked information; for example, present standards do not cover images, digital voice, and digital video. A useful tool kit of exchange formats for basic texts is only now being assembled. The synchronization of content streams (i.e., synchronizing a voice track to a video track, establishing temporal relations between different components in a multimedia object) constitutes another issue for networked multimedia that is just beginning to receive attention.

Underlying network protocols also need some work; good, real-time delivery protocols on the Internet do not yet exist. In LYNCH’s view, highly important in this context is the notion of networked digital object IDs, the ability of one object on the network to point to another object (or component thereof) on the network. Serious bandwidth issues also exist. LYNCH was uncertain if billion-bit-per-second networks would prove sufficient if numerous people ran video in parallel.

LYNCH concluded by offering an issue for database creators to consider, as well as several comments about what might constitute good trial multimedia experiments. In a networked information world the database builder or service builder (publisher) does not exercise the same extensive control over the integrity of the presentation; strange programs “munge” with one’s data before the user sees it. Serious thought must be given to what guarantees integrity of presentation. Part of that is related to where one draws the boundaries around a networked information service. This question of presentation integrity in client-server computing has not been stressed enough in the academic world, LYNCH argued, though commercial service providers deal with it regularly.

Concerning multimedia, LYNCH observed that good multimedia at the moment is hideously expensive to produce. He recommended producing multimedia with either very high sale value, or multimedia with a very long life span, or multimedia that will have a very broad usage base and whose costs therefore can be amortized among large numbers of users. In this connection, historical and humanistically oriented material may be a good place to start, because it tends to have a longer life span than much of the scientific material, as well as a wider user base. LYNCH noted, for example, that American Memory fits many of the criteria outlined. He remarked the extensive discussion about bringing the Internet or the National Research and Education Network (NREN) into the K-12 environment as a way of helping the American educational system.

LYNCH closed by noting that the kinds of applications demonstrated struck him as excellent justifications of broad-scale networking for K-12, but that at this time no “killer” application exists to mobilize the K-12 community to obtain connectivity.

******

+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

DISCUSSION Dearth of genuinely interesting applications on the network a slow-changing situation The issue of the integrity of presentation in a networked environment Several reasons why CD-ROM software does not network

+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

During the discussion period that followed LYNCH’s presentation, several additional points were made.

LYNCH reiterated even more strongly his contention that, historically, once one goes outside high-end science and the group of those who need access to supercomputers, there is a great dearth of genuinely interesting applications on the network. He saw this situation changing slowly, with some of the scientific databases and scholarly discussion groups and electronic journals coming on as well as with the availability of Wide Area Information Servers (WAIS) and some of the databases that are being mounted there. However, many of those things do not seem to have piqued great popular interest. For instance, most high school students of LYNCH’s acquaintance would not qualify as devotees of serious molecular biology.

Concerning the issue of the integrity of presentation, LYNCH believed that a couple of information providers have laid down the law at least on certain things. For example, his recollection was that the National Library of Medicine feels strongly that one needs to employ the identifier field if he or she is to mount a database commercially. The problem with a real networked environment is that one does not know who is reformatting and reprocessing one’s data when one enters a client server mode. It becomes anybody’s guess, for example, if the network uses a Z39.50 server, or what clients are doing with one’s data. A data provider can say that his contract will only permit clients to have access to his data after he vets them and their presentation and makes certain it suits him. But LYNCH held out little expectation that the network marketplace would evolve in that way, because it required too much prior negotiation.

CD-ROM software does not network for a variety of reasons, LYNCH said. He speculated that CD-ROM publishers are not eager to have their products really hook into wide area networks, because they fear it will make their data suppliers nervous. Moreover, until relatively recently, one had to be rather adroit to run a full TCP/IP stack plus applications on a PC-size machine, whereas nowadays it is becoming easier as PCs grow bigger and faster. LYNCH also speculated that software providers had not heard from their customers until the last year or so, or had not heard from enough of their customers.

******

+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

BESSER Implications of disseminating images on the network; planning the distribution of multimedia documents poses two critical implementation problems Layered approach represents the way to deal with users’ capabilities Problems in platform design; file size and its implications for networking Transmission of megabyte size images impractical Compression and decompression at the user’s end Promising trends for compression A disadvantage of using X-Windows A project at the Smithsonian that mounts images on several networks *

+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

Howard BESSER, School of Library and Information Science, University of Pittsburgh, spoke primarily about multimedia, focusing on images and the broad implications of disseminating them on the network. He argued that planning the distribution of multimedia documents posed two critical implementation problems, which he framed in the form of two questions: 1) What platform will one use and what hardware and software will users have for viewing of the material? and 2) How can one deliver a sufficiently robust set of information in an accessible format in a reasonable amount of time? Depending on whether network or CD-ROM is the medium used, this question raises different issues of storage, compression, and transmission.

Concerning the design of platforms (e.g., sound, gray scale, simple color, etc.) and the various capabilities users may have, BESSER maintained that a layered approach was the way to deal with users’ capabilities. A result would be that users with less powerful workstations would simply have less functionality. He urged members of the audience to advocate standards and accompanying software that handle layered functionality across a wide variety of platforms.

BESSER also addressed problems in platform design, namely, deciding how large a machine to design for situations when the largest number of users have the lowest level of the machine, and one desires higher functionality. BESSER then proceeded to the question of file size and its implications for networking. He discussed still images in the main. For example, a digital color image that fills the screen of a standard mega-pel workstation (Sun or Next) will require one megabyte of storage for an eight-bit image or three megabytes of storage for a true color or twenty-four-bit image. Lossless compression algorithms (that is, computational procedures in which no data is lost in the process of compressing [and decompressing] an image—the exact bit-representation is maintained) might bring storage down to a third of a megabyte per image, but not much further than that. The question of size makes it difficult to fit an appropriately sized set of these images on a single disk or to transmit them quickly enough on a network.

With these full screen mega-pel images that constitute a third of a megabyte, one gets 1,000-3,000 full-screen images on a one-gigabyte disk; a standard CD-ROM represents approximately 60 percent of that. Storing images the size of a PC screen (just 8 bit color) increases storage capacity to 4,000-12,000 images per gigabyte; 60 percent of that gives one the size of a CD-ROM, which in turn creates a major problem. One cannot have full-screen, full-color images with lossless compression; one must compress them or use a lower resolution. For megabyte-size images, anything slower than a T-1 speed is impractical. For example, on a fifty-six-kilobaud line, it takes three minutes to transfer a one-megabyte file, if it is not compressed; and this speed assumes ideal circumstances (no other user contending for network bandwidth). Thus, questions of disk access, remote display, and current telephone connection speed make transmission of megabyte-size images impractical.

BESSER then discussed ways to deal with these large images, for example, compression and decompression at the user’s end. In this connection, the issues of how much one is willing to lose in the compression process and what image quality one needs in the first place are unknown. But what is known is that compression entails some loss of data. BESSER urged that more studies be conducted on image quality in different situations, for example, what kind of images are needed for what kind of disciplines, and what kind of image quality is needed for a browsing tool, an intermediate viewing tool, and archiving.

BESSER remarked two promising trends for compression: from a technical perspective, algorithms that use what is called subjective redundancy employ principles from visual psycho-physics to identify and remove information from the image that the human eye cannot perceive; from an interchange and interoperability perspective, the JPEG (i.e., Joint Photographic Experts Group, an ISO standard) compression algorithms also offer promise. These issues of compression and decompression, BESSER argued, resembled those raised earlier concerning the design of different platforms. Gauging the capabilities of potential users constitutes a primary goal. BESSER advocated layering or separating the images from the applications that retrieve and display them, to avoid tying them to particular software.

BESSER detailed several lessons learned from his work at Berkeley with Imagequery, especially the advantages and disadvantages of using X-Windows. In the latter category, for example, retrieval is tied directly to one’s data, an intolerable situation in the long run on a networked system. Finally, BESSER described a project of Jim Wallace at the Smithsonian Institution, who is mounting images in a extremely rudimentary way on the Compuserv and Genie networks and is preparing to mount them on America On Line. Although the average user takes over thirty minutes to