Sharif Digital Repository

In this paper, a novel blind watermarking technique based on quantization is proposed. Quantization is performed in a special domain which converts one dimensional signal to a 2-D one named Point to Point Graph (PPG). Basis of the method is on the separation of this domain into two portions; while, only one portion is quantized. Furthermore, in the dewatermarking procedure, by using the unquantized portion and zero norm, the embedded data can be extracted. The performance of the proposed method is analytically investigated and verified by simulation with artificial Gaussian signals. Experimental results over several audio signals shows the great robustness of the technique in comparison with... 

In this paper, we study the problem of simulating a discrete memoryless channel (DMC) from another DMC under an average-case and an exact model. We present several achievability and infeasibility results, with tight characterizations in special cases. In particular, for the exact model, we fully characterize when a binary symmetric channel can be simulated from a binary erasure channel when there is no shared randomness. We also provide infeasibility and achievability results for the simulation of a binary channel from another binary channel in the case of no shared randomness. To do this, we use the properties of Rényi capacity of a given order. We also introduce a notion of 'channel... 

In this paper, we study the problem of simulating a DMC channel from another DMC channel. We assume that the input to the channel we are simulating is i.i.d. and that the transmitter and receivers are provided with common randomness at limited rates. We prove bounds for simulating point-to-point, MAC and broadcast channels. As a special case, we recover the achievability part of the result of Cuff for point-to-point channel simulation via a noiseless link and shared randomness  

The connectivity between two points in porous media is important for evaluating hydrocarbon recovery in underground reservoirs or toxic migration in waste disposal. For example, the connectivity between a producer and an injector in a hydrocarbon reservoir impact the fluid dispersion throughout the system. The conventional approach, flow simulation, is computationally very expensive and time consuming. Alternative method employs percolation theory. Classical percolation approach investigates the connectivity between two lines (representing the wells) in 2D cross sectional models whereas we look for the connectivity between two points (representing the wells) in 2D aerial models. In this... 

This paper proposes a novel technique to prove a one-shot version of achievability results in network information theory. The technique is not based on covering and packing lemmas. In this technique, we use a stochastic encoder and decoder with a particular structure for coding that resembles both the ML and the joint-typicality coders. Although stochastic encoders and decoders do not usually enhance the capacity region, their use simplifies the analysis. The Jensen inequality lies at the heart of error analysis, which enables us to deal with the expectation of many terms coming from stochastic encoders and decoders at once. The technique is illustrated via four examples: point-to-point... 

Processor allocation in todays many core MPSoCs is a challenging task, especially since the order and requirements of incoming applications are unknown during design stage. To improve network performance, balance the workload across processing cores, or mitigate the effect of hot processing elements in thermal management methodologies, task migration is a method which has attracted much attention in recent years. Runtime task migration was first proposed in multicomputer with load balancing as the major objective. However, specific NoC properties such as limited amount of communication buffers, more sensitivity to implementation complexity, and tight latency and power consumption constraints... 

In this paper, two blind audio watermarking methods using correlated quantization for data embedding with histogram-based detector have been proposed. First, a novel mapping called the point-to-point graph (PPG) is introduced. In this mapping, the value of samples is important as well as the correlation among them. As this mapping increases the dimension of the signal, the data embedding procedure (quantization) will be diversified more securely than that of the 1-D domains such as the time or frequency domains. Hence, two watermarking techniques coined as hard and soft quantization methods based on the quantization of the PPG point radii are suggested. The performance of both techniques is... 

A new technique for coding and decoding of optical signals through the use of polarization is described. In this technique the concept of coding is translated to polarization. In other words, coding is done in such a way that each code represents a unique polarization. This is done by implementing a binary pattern on a spatial light modulator in such a way that the reflected light has the required polarization. Decoding is done by the detection of the received beam's polarization. By linking the concept of coding to polarization we can use each of these concepts in measuring the other one, attaining some gains. In this paper the construction of a simple point-to-point communication where... 

In this paper, we aim to improve the performance and power metrics of packet-switched network-on-chips (NoCs) and benefits from the scalability and resource utilization advantages of NoCs and superior communication performance of point-to-point dedicated links. The proposed method sets up the virtual point-to-point (VIP) connections over one virtual channel (which bypasses the entire router pipeline) at each physical channel of the NoC. We present two schemes for constructing such VIP circuits. In the first scheme, the circuits are constructed for an application based on its task-graph at design time. The second scheme addresses constructing the connections at run-time using a light-weight... 

In this paper, we consider the bacterial point-to-point communication problem with one transmitter and one receiver by considering the ligand receptor binding process. The most commonly investigated signalling model, referred to as the Level Scenario (LS), uses one type of a molecule with different concentration levels for signaling. An alternative approach is to employ multiple types of molecules with a single concentration level, referred to as the Type Scenario (TS). We investigate the trade-offs between the two scenarios for the ligand receptor from the capacity point of view. For this purpose, we evaluate the capacity using numerical algorithms. Moreover, we derive an upper bound on the... 

predicting the latency between hosts in the internet can play a significant rolein the improvement of the performance of many services that use latency distances among hosts as a decision making input. Although, the information regarding the point to point delay among internet peers is required in many applications, such information is not easily available to the peers. Latency data acquisition requires a considerableamount of measurements to be performed at each node in order for that node to keep a recordof its latency to all the other nodes. Moreover, the measurements need to be regularly repeated in order to be updatedagainst the network dynamics where the latency values are frequently... 

In this paper, we aim to improve the performance and power metrics of packet-switched network-on-chips (NoCs) and benefits from the scalability and resource utilization advantages of NoCs and superior communication performance of point-to-point dedicated links. The proposed method sets up the virtual point-to-point (VIP) connections over one virtual channel (which bypasses the entire router pipeline) at each physical channel of the NoC. We present two schemes for constructing such VIP circuits. In the first scheme, the circuits are constructed for an application based on its task-graph at design time. The second scheme addresses constructing the connections at run-time using a light-weight... 

Network-on-Chip (NoC) paradigm has emerged as a revolutionary methodology to integrate numerous IP blocks on a single chip. The achievable performance of adopting NoCs is constrained by the performance limitation mainly imposed by the metal wires that are the physical realization of communication channels. According to the International Technology Roadmap for Semiconductors (ITRS) report, new interconnect paradigms providing huge bandwidth is in need for future products. The current wired channels have limited bandwidth, and consequently, they limit the performance enhancements that NoC architectures can provide. Optical interconnects are capable of achieving better performance via... 

Swimming microrobots have a variety of applications including drug delivery, sensing, and artificial fertilization. Their small size makes onboard actuation very hard, and therefore an external source such as the magnetic field is a practical way to steer and move the robot. In this paper, we have designed a novel microrobot steered by magnetic paddles. We have also discussed design parameters where, based on the conducted simulation, the robot speed reaches 520 um/s. It is shown that the microrobot speed depends on the robot paddle dimensions. According to the microrobots motion characteristics and their different reactions to the same input, we have designed a steering strategy for... 

In this study, the authors propose a processor allocation mechanism for run-time assignment of a set of communicating tasks of input applications onto the processing nodes of a chip multiprocessor, when the arrival order and execution lifetime of the input applications are not known a priori. This mechanism targets the on-chip communication and aims to reduce the power and latency of the network-on-chip employed as the communication infrastructure. In this work, the authors benefit from the advantages of non-contiguous processor allocation mechanisms, by allowing the tasks of the input application mapped onto disjoint regions (submeshes) and then virtually connecting them by bypassing the... 

A gyroless deterministic attitude determination algorithm based on simulation of sun in eclipse is stated in this paper and has been compared to stochastic filters like extended Kalman filter and unscented Kalman filter. Attitude determination with low cost sensors such as magnometer and sun sensor results in usage of recursive algorithms such as Kalman filter which has the probability of divergence, but with deterministic point to point algorithm such as the one introduced in this paper we can be sure to have an attitude determination with a fixed maximum error. Proposed method has been compared with Extended Kalman Filter and Unscented Kalman filter due to its modeling error, robustness... 

In this paper, a novel quantization based watermarking method is proposed. For blind detection, a set of nonlinear convex functions based on geometric mean are investigated. In order to achieve minimum distortion, the optimum function set is found. The algorithm is implemented on the approximation coefficients of wavelet transform for natural images. In order to make the algorithm more robust and imperceptible, a new transform domain called Point to Point Graph (PPG), which converts a 1-D signal to a 2-D one, has been used. The error probability of the proposed scheme is analytically investigated. Simulation results show that this algorithm has great robustness against common attacks such as... 

A method to setup virtual point-to-point links between the cores of a packet-switched network-on-chip is presented in this paper which aims at reducing the NoC power consumption and delay. The router architecture proposed in this paper provides packet-switching, as well as a number of virtual point-to-point, or VIP (VIrtual Point-to-point) for short, connections. This is achieved by designating one virtual channel at each physical channel of a router to bypass the router pipeline. The mapping and routing algorithm exploits these virtual channels and tries to virtually connect the source and destination nodes of high-volume communication flows during task-graph mapping and route selection...