Ralf Steinmetz

Bio: Ralf Steinmetz is an academic researcher from Technische Universität Darmstadt. The author has contributed to research in topics: Quality of service & The Internet. The author has an hindex of 49, co-authored 917 publications receiving 14843 citations. Previous affiliations of Ralf Steinmetz include Lancaster University & IBM.

i-LAND: an interactive landscape for creativity and innovation

Abstract: We describe the i-LAND environment which constitutes an example of our vision of the workspaces of the future, in this case supporting cooperative work of dynamic teams with changing needs. i-LAND requires and provides new forms of human-computer interaction and new forms of computer-supported cooperative work. Its design is based on an integration of information and architectural spaces, implications of new work practices and an empirical requirements study informing our design. i-LAND consists of several roomware components, i.e. computer-aug- mented objects integrating room elements with information technology. We present the current realization of i-LAND in terms of an interactive electronic wall, an interactive table, two computer-enhanced chairs, and two bridges for the Passage-mechanism. This is complemented by the description of the creativity support application and the technological infrastructure. The paper is accompanied by a video figure in the CHI99 video program.

A media synchronization survey: reference model, specification, and case studies

Abstract: Researchers have addressed multimedia synchronization from various perspectives. The major issues include how to specify and how to implement synchronization. Especially in the specification area a variety of techniques have been published and implemented. This survey summarizes briefly synchronization requirements, presents a multimedia synchronization reference model, shows details of various specification approaches and applies the reference model to compare existing prominent approaches as case studies.

Human perception of jitter and media synchronization

Abstract: Multimedia synchronization comprises both the definition and the establishment of temporal relationships among media types. The presentation of 'in sync' data streams is essential to achieve a natural impression, data that is 'out of sync' is perceived as being somewhat artificial, strange, or even annoying. Therefore, the goal of any multimedia system is to enable an application to present data without no or little synchronization errors. The achievement of this goal requires a detailed knowledge of the synchronization requirements at the user interface. The paper presents the results of a series of experiments about human media perception that may be used as 'quality of service' guidelines. The results show that skews between related data streams may still give the effect that the data is 'in sync' and gives some constraints under which jitter may be tolerated. The author uses the findings to develop a scheme for the processing of nontrivial synchronization skew between more than two data streams.

Peer-to-Peer Systems and Applications

Abstract: Part I Peer-to-Peer: Notion, Areas, History and Future: What is this Peer-to-Peer about?- Past and Future.- Application Areas.- Part II Unstructured Peer-to-Peer Systems: First and Second Generation of Peer-to-Peer Systems.- Random Graphs, Small-Worlds and Scale-Free Networks.- Part III Structured Peer-to-Peer Systems: Distributed Hash Tables.- Selected DHT Algorithms.- Reliability and Load Balancing in DHTs.- P-Grid: Dynamics of Self-Organizing Processes in Structured P2P Systems.- Part IV Peer-to-Peer-Based Applications: Application-Layer Multicast.- ePost.- Distributed Computing - GRID Computing.- Web Services and Peer-to-Peer.- Part V Self-Organization: Characterization of Self-Organization.- Self-Organization in Peer-to-Peer Systems.- Part VI Search and Retrieval: Peer-to-Peer Search and Scalability.- Algorithmic Aspects of Overlay Networks.- Schema-Based Peer-to-Peer Systems.- Supporting Information Retrieval in Peer-to-Peer Systems.- Hybrid Peer-to-Peer Systems.- Part VII Peer-to-Peer Traffic and Performance Evaluation: ISP Platforms under a Heavy Peer-to-Peer Workload.- Traffic Characteristics and Performance Evaluation of Peer-to-Peer Systems.- Part VIII Peer-to-Peer in Mobile and Ubiquitous Environments: Peer-to-Peer in Mobile Environments.- Spontaneous Collaboration in Mobile P2P Networks.- Epidemic Data Dissemination for Mobile Peer-to-Peer Lookup Services.- Peer-to-Peer and Ubiquitious Computing.- Part IX Business Applications and Markets: Business Applications and Revenue Models.- Peer-to-Peer Market Management.- A Peer-to-Peer Framework for Electronic Markets.- Part X Advanced Issues: Security-Related Issues in Peer-to-Peer Networks.- Accounting in Peer-to-Peer Systems.- The PlanetLab Platform

Synchronization properties in multimedia systems

Abstract: Multimedia is defined as the integrated generation, representation, processing, storage, and dissemination of independent machine-processable information expressed in multiple time-dependent and time-independent media such as data, graphics, drawings, voice, audio, and video. The characteristics of synchronization mechanisms desirable for central and distributed multimedia systems are addressed. The concept of multimedia objects as components of an object-based model for a multimedia system is introduced. The essential new synchronization requirement is restricted blocking together with synchronization features covering real-time aspects. Existing synchronization mechanisms can be altered or new ones defined to meet these requirements. >

I and i

Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

Machine learning

Abstract: Machine Learning is the study of methods for programming computers to learn. Computers are applied to a wide range of tasks, and for most of these it is relatively easy for programmers to design and implement the necessary software. However, there are many tasks for which this is difficult or impossible. These can be divided into four general categories. First, there are problems for which there exist no human experts. For example, in modern automated manufacturing facilities, there is a need to predict machine failures before they occur by analyzing sensor readings. Because the machines are new, there are no human experts who can be interviewed by a programmer to provide the knowledge necessary to build a computer system. A machine learning system can study recorded data and subsequent machine failures and learn prediction rules. Second, there are problems where human experts exist, but where they are unable to explain their expertise. This is the case in many perceptual tasks, such as speech recognition, hand-writing recognition, and natural language understanding. Virtually all humans exhibit expert-level abilities on these tasks, but none of them can describe the detailed steps that they follow as they perform them. Fortunately, humans can provide machines with examples of the inputs and correct outputs for these tasks, so machine learning algorithms can learn to map the inputs to the outputs. Third, there are problems where phenomena are changing rapidly. In finance, for example, people would like to predict the future behavior of the stock market, of consumer purchases, or of exchange rates. These behaviors change frequently, so that even if a programmer could construct a good predictive computer program, it would need to be rewritten frequently. A learning program can relieve the programmer of this burden by constantly modifying and tuning a set of learned prediction rules. Fourth, there are applications that need to be customized for each computer user separately. Consider, for example, a program to filter unwanted electronic mail messages. Different users will need different filters. It is unreasonable to expect each user to program his or her own rules, and it is infeasible to provide every user with a software engineer to keep the rules up-to-date. A machine learning system can learn which mail messages the user rejects and maintain the filtering rules automatically. Machine learning addresses many of the same research questions as the fields of statistics, data mining, and psychology, but with differences of emphasis. Statistics focuses on understanding the phenomena that have generated the data, often with the goal of testing different hypotheses about those phenomena. Data mining seeks to find patterns in the data that are understandable by people. Psychological studies of human learning aspire to understand the mechanisms underlying the various learning behaviors exhibited by people (concept learning, skill acquisition, strategy change, etc.).

Out of the Crisis

Abstract: According to W. Edwards Deming, American companies require nothing less than a transformation of management style and of governmental relations with industry. In Out of the Crisis, originally published in 1982, Deming offers a theory of management based on his famous 14 Points for Management. Management's failure to plan for the future, he claims, brings about loss of market, which brings about loss of jobs. Management must be judged not only by the quarterly dividend, but by innovative plans to stay in business, protect investment, ensure future dividends, and provide more jobs through improved product and service. In simple, direct language, he explains the principles of management transformation and how to apply them.

Computer vision : a modern approach = 计算机视觉 : 一种现代的方法

Abstract: From the Publisher: The accessible presentation of this book gives both a general view of the entire computer vision enterprise and also offers sufficient detail to be able to build useful applications. Users learn techniques that have proven to be useful by first-hand experience and a wide range of mathematical methods. A CD-ROM with every copy of the text contains source code for programming practice, color images, and illustrative movies. Comprehensive and up-to-date, this book includes essential topics that either reflect practical significance or are of theoretical importance. Topics are discussed in substantial and increasing depth. Application surveys describe numerous important application areas such as image based rendering and digital libraries. Many important algorithms broken down and illustrated in pseudo code. Appropriate for use by engineers as a comprehensive reference to the computer vision enterprise.