The use of network delay estimation for multimedia data retrieval

Multimedia data have specific temporal presentation requirements. For example in video conferencing applications the voice and images of the participants must be delivered and presented synchronously. These requirements can be achieved by scheduling or managing system resources. We present a technique called limited a priori scheduling (LAP) to manage the delivery channel from source to destination for digital multimedia data. By using delay estimation a LAP scheduler can retrieve stored digital media spanning arbitrary networks with unspecified delays. The use of delay estimation also facilitates selective degradation of service in bandwidth and buffer limited situations. Such degradation enables the continuous real-time playout and synchronization of various media arriving from different sources. The performance of the LAP scheduler is described based on implementation and experimentation using Ethernet     

An algebraic characterization of planar graphs

A cycle in a graph is a set of edges that covers each vertex an even number of times. A cocycle is a collection of edges that intersects each cycle in an even number of edges. A bicycle is a collection of edges that is both a cycle and a cocycle. The cycles, cocycles, and bicycles each form a vector space over the integers modulo two when addition is defined as symmetric difference of sets. In this paper we examine the relationship between the left-right paths in a planar graph and the cycle space, cocylce space, and bicycle space. We show that planar graphs are characterized by the existence of a diagonal—a double cover by tours that interacts with the cycle space, cocycle space, and bicycle space in a special manner. This generalizes a result of Rosenstiehl and Read that characterized those planar graphs with no nonempty bicycles. © 1995 John Wiley & Sons, Inc.     

On webs of maximum rank

This paper contains two results on webs of maximal rank. First, we show that at each point, the web normals for a codimension-r web of maximum r-rank are (r−1)-dimensional generators of a rational normal scroll in the projectivized tangent space to the web domain, an extension of a theorem of Chern and Griffiths in the case r=2 [5]. We use this statement to deduce that webs of maximum rank are almost-Grassmannizable in the sense of Akivis [1]. Second, we show that there are exceptional (that is, maximum rank, but not algebraizable) webs W(2n, n, 2) for all n≥2. The construction relies on the properties of zero-cycles on algebraic K3 surfaces.     

Multimedia synchronization protocols for broadband integratedservices

Protocols to provide synchronization of data elements with arbitrary temporal relationships of both stream and non-stream broadband traffic types are proposed. It is specified that the provision of a synchronization function be performed within a packet switched network, and, accordingly, a two-level communication architecture is presented. The lower level, called the network synchronization protocol (NSP), provides the ability to establish and maintain individual connections with specified synchronization characteristics. The upper level, the application synchronization protocol (ASP), supports an integrated synchronization service for multimedia applications. The ASP identifies the temporal relationships among an application's data objects and manages the synchronization of arriving data for playout. The proposed NSP and ASP are mapped to the session and application layers of the open-systems-interconnection (OSI) reference model, respectively     

Formation constants for the complexes of orthophosphate with magnesium and hydrogen ions

The system of orthophosphate, magnesium and hydrogen ions in aqueous solution at 25 degrees and I = 0.2M chloride has been characterized by means of glass-electrode potentiometry. Protonation constants for orthophosphate species and formation constants for the complexes MgH(2)PO(+)(4), MgHPO(4), MgPO(4)(-) and MgOH(+) are reported.     

Intensity-induced stopband bending in periodic nonlinearmultilayers

A simple and physically appealing theory is developed to describe the intensity-induced “bending” of the stopband region of nonlinear multilayered devices. The theory is subsequently used to graphically map the general response of devices as a function of input intensity and phase detuning. Deeper insight into conventional (known) phenomena is obtained, while new phenomena are revealed, such as “hard” optical limiting, intensity discrimination, and a new arrangement for bistability     

A high-efficiency 200 W average power copper HyBrID laser

The high-power, high efficiency copper HyBrID laser has been scaled to large bore (6 cm), with an active length of 200 cm, to generate, as an oscillator, an average output power of 201 W at 1.9% efficiency (based on stored energy) in the green (510.6 nm) and yellow (578.2 nm). For an output power of 120 W, the efficiency reached 3.2%, when the pulse recurrence frequency was 17 kHz. The factors which make the interacting circuit superior to conventional capacitor transfer circuits for the excitation of copper lasers are discussed     

Increased sample throughput in HPLC using sample switching

Summary Column switching methods are described which demonstrate an alternative approach to the reduction of analytical time in HPLC. Although most methods use a combination of techniques, it has been possible to group them into major categories involving column cleanup, sample cleanup, multicolumn methods and boxcar chromatography. Presented at the 15th International Symposium on Chromatography, Nürnberg, October 1984