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Emin Gabrielyan

Publications and source records attributed to Emin Gabrielyan.

4 recordsLinked to original sources

Dynamic routing based on call quality

The telephony over IP (ToIP) is becoming a new trend in technology widely used nowadays in almost all business sectors. Its concepts rely on transiting the telephone communications through the IP network. Today, this technology is deployed increasingly what the cause of emergence of companies is offering this service as Switzernet. For several highly demanded destinations, recently fake vendors appeared in the market offering voice termination but providing only false answer supervision. The answered signal is returned immediately and calls are being charged without being connected. Different techniques are used to keep the calling party on the line. One of these techniques is to play a record of a ring back tone (while the call is already being charged). Another, more sophisticated technique is to play a human voice randomly picked up from a set of records containing contents similar to: hello, hello, I cannot hear you Apart the fact that the fallaciously established calls are charged at rates of real calls, such malicious routes seriously handicap the switching process. The system does not detect a failure on signaling level and is unable to attempt the call via backup routes, the call technically being already connected. Once the call flow falls into such trap, the calls will continue being routed via the fraudulent route until a manual intervention.

cs.NI

The basics of line moire patterns and optical speedup

We are addressing the optical speedup of movements of layers in moire patterns. We introduce a set of equations for computing curved patterns, where the formulas of optical speedup and moire periods are kept in their simplest form. We consider linear movements and rotations. In the presented notation, all periods are relative to the axis of movements of layers and moire bands. KEYWORDS: moire patterns, line moire, superposition images, optical speedup, moire speedup, moire magnification, periodic moire

physics.optics

Reliable Multi-Path Routing Schemes for Real-Time Streaming

In off-line streaming, packet level erasure resilient Forward Error Correction (FEC) codes rely on the unrestricted buffering time at the receiver. In real-time streaming, the extremely short playback buffering time makes FEC inefficient for protecting a single path communication against long link failures. It has been shown that one alternative path added to a single path route makes packet level FEC applicable even when the buffering time is limited. Further path diversity, however, increases the number of underlying links increasing the total link failure rate, requiring from the sender possibly more FEC packets. We introduce a scalar coefficient for rating a multi-path routing topology of any complexity. It is called Redundancy Overall Requirement (ROR) and is proportional to the total number of adaptive FEC packets required for protection of the communication. With the capillary routing algorithm, introduced in this paper we build thousands of multi-path routing patterns. By computing their ROR coefficients, we show that contrary to the expectations the overall requirement in FEC codes is reduced when the further diversity of dual-path routing is achieved by the capillary routing algorithm.

cs.NI

Fault-Tolerant Real-Time Streaming with FEC thanks to Capillary Multi-Path Routing

Erasure resilient FEC codes in off-line packetized streaming rely on time diversity. This requires unrestricted buffering time at the receiver. In real-time streaming the playback buffering time must be very short. Path diversity is an orthogonal strategy. However, the large number of long paths increases the number of underlying links and consecutively the overall link failure rate. This may increase the overall requirement in redundant FEC packets for combating the link failures. We introduce the Redundancy Overall Requirement (ROR) metric, a routing coefficient specifying the total number of FEC packets required for compensation of all underlying link failures. We present a capillary routing algorithm for constructing layer by layer steadily diversifying multi-path routing patterns. By measuring the ROR coefficients of a dozen of routing layers on hundreds of network samples, we show that the number of required FEC packets decreases substantially when the path diversity is increased by the capillary routing construction algorithm.

cs.NI