Sharif Digital Repository

This paper presents an analysis of the effects and propagation of faults in the open-core 32-bit OpenRISC 1200 microprocessor. The analysis is based on a total of 13,000 transient faults injected into 65 parts of the CPU module in the OpenRISC 1200 core described at the RTL model. A comparison of the effects of faults on the various parts of the CPU including the pipeline's registers, the CPU component such as the register file, the control unit, and the ALU, and the data and address buses is done. It is shown that about 30%, 40% and 27% of injected faults terminated in address, data, and control errors respectively. About 28% of all injected faults resulted in failures. © 2008 IEEE  

By the immense growth of the Web-Based Social Networks (WBSNs), the role of trust in connecting people together through WBSNs is getting more important than ever. In other words, since the probability of malicious behavior in WBSNs is increasing, it is necessary to evaluate the reliability of a person before trying to communicate with. Hence, it is desirable to find out how much a person should trust another one in a network. The approach to answer this question is usually called trust inference. In this paper, we propose a new trust inference algorithm (Called RN-Trust) based on the resistive networks concept. The algorithm, in addition to being simple, resolves some problems of previously... 

A novel burst correction coding for correction of bulk errors in block-based image coding is developed. The algorithm makes artificial correlation between image pixels that distorts the image. By choosing appropriate parameters, one can control this distortion to lie in acceptable ranges. Our method can exactly correct an erroneously decoded block when using lossless codecs. In the presence of lossy codecs, the algorithm encounters a processing error which makes a noisy image after correction. The Wiener filter is used to reduce this noise. Experimental results show that our method can correct corrupted large blocks in images; the ability that other previously reported approaches have not... 

This paper presents an FPGA-based fault injection tool, called FITO that supports several synthesizable fault models for dependability analysis of digital systems modeled by Verilog HDL. Using the FITO, experiments can be performed in real-time with good controllability and observability. As a case study, an OpenRISC 1200 microprocessor was evaluated using an FPGA circuit. About 4000 permanent, transient, and SEU faults were injected into this microprocessor. The results show that the FITO tool is more than 79 times faster than a pure simulation-based fault injection with only 2.5% FPGA area overhead. © 2008 IEEE  

In assembly level programming we need to know the mnemonic of each assembly instruction. But it is not so easy to remember mnemonics of all instructions, while the instruction set of Pentium processor includes 280 instructions. In this paper we introduce a new programming approach to assembly level programming in which most important assembly instructions (about 100 instructions) can be substituted for simple equivalents. These equivalent instructions are based on simple familiar operators and make a large simplification in assembly programming. This new language has a free format structure and hence is called Free Format Assembly Language. Evaluating the performance of this language using a... 

Here a special state variable feedback or state feedback for short is introduced with the main objective of providing a convenient method for decoupling a MIMO transfer matrix. Decoupling in general and decoupling via state feedback in particular offer obvious advantages in the design and synthesis of controllers for MIMO systems. The early parts of this paper deal with the eigenvalues, poles, and zeros as well as the controllability and observability properties of the proposed closed-loop system as compared with those of the open-loop system. The proposed method is tested on a model of a realistic physical system and results are illustrated. © 2008 IEEE  

After the emergence of modern technologies in the field of information technologies (IT), virtual learning has attained a new form. The way of announcing exams' grades is an important topic in e-learning. For announcing exams' grades on the web, various methods have been proposed. In this paper, first some common methods for announcing students' grades are reviewed, then three new methods which are named "Virtual Grade", "Steganography Grades", and "Grade HIP" are introduced and the result of implementing these methods for announcing the grades of some courses at the some Iranian universities are provided. Also these methods and their results are analyzed. Finally these three new methods are... 

In this paper a new class of invertible watermarking approach based on quantization has been introduced. Based on the necessary conditions (blindness, reversibility and imperceptibility), a set of linear convex functions which satisfy these requirements are found. Then the optimum of this function set with the least distortion has been selected. The main advantage of this method is that the inserted distortion can be easily controlled by adjusting quantization levels. The low computational complexity is another advantage of this method. Experimental results show that the proposed algorithm achieves higher embedding capacity while its distortion is lower than other invertible watermarking... 

High reliability, low power consumption and high performance are key objectives in the design of NoCs. These three design objectives should be considered simultaneously in order to have an optimal design. This paper proposes a method to reduce power consumption of an application specific NoC. This is done in two steps: 1) Extra virtual channels are used in the router architecture to increase the performance in an application specific NoC, and 2) The amount of the performance gain is then set to the initial point using frequency scaling technique, hence reducing the power consumption, without corruption of reliability. The simulation results show that the method can reduce the power... 

Several methodologies with their own characteristics have been proposed in the area of agent-oriented software engineering. Consequently, deciding which methodology to select in a specific case is an important issue and it can lead to decrease software development cost and effort. Thus, importance of evaluation of methodologies will be highlighted in choosing the appropriate methodology in the development process of an application. It can also help in developing new methodologies and improving existing ones. In this paper, we are going to provide an evaluation framework of agent oriented methodologies. To demonstrate the usage of the suggested framework, it is applied to evaluate two... 

In this paper, we propose a novel approach to extract a network of half adders from the gate-level net-list of an addition circuit while no internal equivalences exist. The technique begins with a gatelevel net-list and tries to map it into word-level adders based on an efficient bit-level adder representation. It will be shown that the proposed technique is suitable for several gate-level architectures of multipliers, as it extracts adder components in a step-wise method. This approach can also be generalized to other arithmetic circuits. In order to evaluate the effectiveness of our approach, we run it on several arithmetic circuits and compare experimental results with those of... 

This paper investigates fault effects and error propagation in a FlexRay-based network with hybrid topology that includes a bus subnetwork and a star subnetwork "The investigation is based on about 43500 bit-flip fault injection inside different parts of the FlexRay communication controller. To do this, a FlexRay communication controller is modeled by Verilog HDL at the behavioral level. Then, this controller is exploited to setup a FlexRay-based network composed of eight nodes (four nodes in the bus subnetwork and four nodes in the star subnetwork). The faults are injected in a node of the bus subnetwork and a node of the star subnetwork of the hybrid network. Then, the faults resulting in... 

In this work, we extend a numerical tool capable of solving compressible and incompressible gas flows to study the momentum and heat transfer rates in micro/nano channels with high aspect ratio (L/H = 8000), where the compressibility effect is dominant. The constant heat flux thermal boundary condition is firstly applied at the wall. Next, the flow regime is extended to the early transition regime employing a high order slip velocity boundary condition based on the kinetic theory assumptions. The accuracy of the present results in the slip flow regimes is evaluated against other available theoretical and experimental results. The thermal and compressibility effects on the pressure and... 

People usually use trust and reputation to cope with uncertainty which exists in the nature and routines. The existing approaches for inferring trust rely on homogeneous relations. In other words, trust is just inferred by a homogeneous relation. In this paper, we present a new model for inferring trust using heterogeneous social networks; we use relation extraction to make a trust relation from the other relation such as friendship and the college relation and then introduced an algorithm to infer trust using extracted relation. In order to get higher performance, we extend relation extraction problem by proposing a genetic algorithm. This algorithm is more scalable, interpretable and... 

Agile software development methodologies have been greeted with enthusiasm by many software developers, yet their widespread adoption has also resulted in closer examination of their strengths and weaknesses. While analyses and evaluations abound, the need still remains for an objective and systematic appraisal of Agile processes specifically aimed at defining strategies for their improvement. We provide a review of the strengths and weaknesses identified in Agile processes, based on which a Strengths-Weaknesses-Opportunities-Threats (SWOT) analysis of the processes is performed. We suggest this type of analysis as a useful tool for highlighting and addressing the problem issues in Agile... 

Reconfigurability for a component of a distributed component-based system means ability to replace the component with a new one, in presence of the other components. In this context, substitutability and compatibility of components should be analyzed. In this paper, we use I/O-Constraint Automata to model behavior of components and propose enough formalism for substitutability and compatibility analysis. We show that in the context of distributed non-blocking components, there is a relation weaker than usual simulation relation in automata theory for notion of substitutability. We illustrate the relation between substitutability and compatibility to reason about the reconfigurability of a... 

Nowadays the Internet users are from different ages and groups. Disabled people are a group of the Internet users. Some websites are especially created for these people. One group of the disabled people are deaf persons. They have a special talking language which is named sign language. Here we present a method to encourage them, esp. children, to learn the sign language. In this method, when a deaf person wants to enter a website which is created for deaf persons, a word is shown as a movie using a sign language. The user should recognize the word and select it from a list. If the user understands the sign language and recognizes the word, he/she can enter the website. This project has been... 

After the emergence of modern technologies in recent years, learning methods have attained a new form. Using game consoles as educational tools is a new idea which is gained attracted by some researchers. This paper proposes a new method for improving English lab classes using Sony PSP (PlayStation Portable) handheld game consoles especially for Iranian schools. © 2008 IEEE  

Ultrasound waves have been used in these days for most surgeries. They are applied to remove body tissues through surgery, for example in removing eye lens in cataract surgery. In a nutshell, a 3mm incision near cornea has been created and then after, a folded lens will be implanted and the patient can be released soon after the operation. The process is done by a vibrating metal tip in order to emulsify the lenses and the small particles will aspirate the debris through the hollow center of the tip. The problem of this procedure in some cases is thermal damage. This research addresses the aforementioned problem through an important parameter, different operating modes of the system. The... 

Routing is a very important matter for ad hoc networks which means choosing the suitable and correct path for transferring data from a source node to a destination node. Today, the methods using several paths for routing are attended very much. In this paper, a new plan in multiple paths On-Demand Distance Vector (AODV) routing is presented which its routing is based on the distance of nodes from the center of the network. In this new routing algorithm, the number of dropped packets will be decreased and indeed this will be happened with more balancing in the network. This claim will be proved by some simulations using ns2 (network simulator)