Sharif Digital Repository

Compressed images such as JPEG when transmitted over communication channels are susceptible to channel noise and/or erasure, which causes losses of blocks of pixels or macroblocks. Recovery of a large block in an image is a difficult task. In this paper we propose a novel method that addresses this problem and can exactly recover a lost block. Moreover, the proposed algorithm is fast enough to be implemented in real time. Simulation results show that our method is faster than previous methods proposed in the literature with less distortion  

In this paper, we integrate an assertion-based verification methodology with our object-oriented system-level synthesis methodology to address the problem of HW/SW co-verification. In this direction a system-level assertion language is defined. The system-level assertions can be used to monitor the current state of system or flow of transactions. These assertions are automatically converted to "monitor hardware" or "monitor software" during the system-level synthesis process depending on their type and also synthesis style of their corresponding functions. The synthesized assertions are functionally equivalent to their original system-level assertions, and hence, can be reused to verify the... 

Purpose - This study aims to present compatible computational fluid dynamics procedure for calculation of incompressible three-dimensional time-dependent flow with complicated free surface deformation. A computer software is developed and validated using a variety of academic test cases. Design/methodology/approach - Two fluids are modeled as a single continuum with a fluid property jump at the interface by solving a scalar transport equation for volume fraction. In conjunction, the conservation equations for mass and momentum are solved using fractional step method. Here, a finite volume discretisation and colocated arrangement are used. Findings - The developed code results in accurate... 

Dependability evaluation of embedded systems due to the integration of hardware and software parts is difficult to analyze. In this paper, we have proposed an experimental method to determine sensitivity to soft errors in an embedded system exploiting Altera SRAM-based FPGAs. The evaluation is performed using both the hardware and software parts of the embedded system in a single framework. To do this, the HDL hardware model of the target system as well as the C-written software codes of the target system, are required. Both permanent and transient faults are injected into the partially- or fully-synthesizable hardware of the target system and this can be performed during the design cycle of... 

Analysis of multi dimensional interactions of flow of energy in passenger vehicle is a complex task that necessitates development and utilization of analytical tools. Development of analytical tools with high complexity is usually based on conclusions of many concepts and theories from different scientific disciplines. In this approach, Passenger vehicle is supposed to be organized in the form of a firm and appears in the market that oriented towards establishing an effective energy supply system which may be identified as delivering the product (person kilometer or tone kilometer) with minimum operation costs. To this end, an optimization model named power software founded on theory of firm... 

In this paper, we describe an innovative method to model and solve spatio-temporal behavior of nuclear reactor cores via three-dimensional multilayer cellular neural networks. This method uses electrical elements and the existing duality between neutronic and thermal-hydraulic parameters of nuclear reactors. The relevant electrical circuit can be simulated by existing professional electrical circuit software. This research goes beyond our previous efforts to use a neural computing approach in the nuclear field. Modeling and solving simple nuclear reactor kinetic equations is now expanded to a complete dynamic calculation, integrating the core thermal-hydraulic models and the relevant... 

In this paper we introduce a mathematical modeling tool (called Classic General Model: CGM) for the general problem of hardware-software codesign so that different partitioning algorithms can be easily and quickly developed and compared in this same framework. CGM introduces a simple but efficient model which supports single/multiprocessor, primal and dual approaches, fine or coarse granularity. CGM determines solutions by stating Mapping, Implementation and Permutation arrays. For judging among solutions of a certain algorithm, an Objective Function is defined. After modeling the problem by CGM we have a classic problem: finding the best values for elements of three arrays to optimize the... 

We have recently introduced a high-level extension for stochastic activity networks (SANs) called coloured stochastic activity networks (CSANs). CSANs have several distinguishing properties, which make them quite appropriate for modeling and evaluation of software performance and dependability. CSANs have introduced a construct called coloured place for data manipulation. A coloured place holds a list of tokens of a userdefined token type. CSAN models can be evaluated by state space analysis techniques or discrete-event simulation. However, their state spaces will become very large, even for a small CSAN model. For efficient evaluation of these models by state space analysis methods, we will... 

This paper presents a software-based error detection scheme called enhanced committed instructions counting (ECIC) for embedded and real-time systems using commercial off-the-shelf (COTS) processors. The scheme uses the internal performance monitoring features of a processor, which provides the ability to count the number of committed instructions in a program. To evaluate the ECIC scheme, 6000 software induced faults are injected into a 32-bit Pentium® processor. The results show that the error detection coverage varies between 90.52% and 98.18%, for different workloads. © 2004 Elsevier Ltd. All rights reserved  

In this article by employing the principle of continuum damage mechanics and solving the governing equations using finite element technique, the damage process in a composite media like a human long bone has been studied. To do this, primarily a CT scan of a femur is converted to proper model usable for a F.E. model. After applying load incrementally with monotonic nature, the state of stress or strain in each element and consequently in medium are calculated using finite element software. Based on the principle of continuum damage and the value of stress in each element, the damage rate is calculated and the mechanical properties at that point are updated for the next step of loading. This... 

One of the ways of giving a considerable handle on the account of developing this processes using simulating software. In this work the primary simulation in Aspen plus software done for comparison of various equations of state. Hence, for preparation of one reliable and exact model, the primary prepared model studied for different kinds of Equations of state, activity coefficient and calculation methods of Equilibrium constant in existing simulator software bed. Designing Dimethyl Ether pilot plant on the basis of reactor simulation is achieved by using the compatibility between simulation data and empirical data relevant to the industrial unit. The constants of the kinetic model were... 

This paper presents a new method to analyze the bidding strategies of Generating Companies (GENCOs) with regard to demand elasticity. It is assumed that the available information of each GENCO about its opponents is incomplete and only the minimum and maximum generation levels of their opponents, as well as their fuel type, are known. In the proposed methodology, GENCOs prepare their strategic bids according to a Supply Function Equilibrium (SFE) model. GENCOs will change their bidding strategies until Nash equilibrium points are obtained. The general Algebraic Modeling System (GAMS) has been used to solve the maximization modules using the MINOS optimization software with non Linear... 

[Context and Motivation] Software requirements are affected by the knowledge and confidence of software engineers. Analyzing the interrelated impact of these factors is difficult because of the challenges of assessing knowledge and confidence. [Question/Problem] This research aims to draw attention to the need for considering the interrelated effects of confidence and knowledge on requirements quality, which has not been addressed by previous publications. [Principal ideas/results] For this purpose, the following steps have been taken: 1) requirements quality was defined based on the instructions provided by the ISO29148:2011 standard, 2) we selected the symptoms of low qualified... 

The paper presents a comparison of steam methane reforming (SMR), sorption enhanced steam methane reforming (SE-SMR), auto-thermal reforming (ATR), and sorption enhanced auto-thermal reforming (SE-ATR) in a fixed bed reformer for hydrogen production. A one-dimensional, unsteady-state heterogeneous reactor model for each process which includes mass and thermal dispersion in the direction of flow and axial pressure distribution, has been simulated using gPROMS® 4.0.1 model builder, while CEA and Aspen Plus® have been employed to analyze the equilibrium performance and simulate the process flowsheets of individual process respectively. The performance of the individual hydrogen production... 

Scrum is currently the most widely used agile methodology. However, it is regarded as a framework rather than a concrete process. Unfortunately, the resources available on Scrum do not explicitly define its variable parts and do not offer proper guidance on how to resolve those variabilities. Process (re)configuration is thus left to Scrum Retrospective sessions; this can delay the vital decisions that can significantly improve the process before problems arise. This paper aims to address the problems associated with configuring/reconfiguring Scrum by identifying all the variabilities (variation points) in the Scrum framework, along with the situations where a variation point can be resolved... 

Scrum is currently the most widely used agile methodology. However, it is regarded as a framework rather than a concrete process. Unfortunately, the resources available on Scrum do not explicitly define its variable parts and do not offer proper guidance on how to resolve those variabilities. Process (re)configuration is thus left to Scrum Retrospective sessions; this can delay the vital decisions that can significantly improve the process before problems arise. This paper aims to address the problems associated with configuring/reconfiguring Scrum by identifying all the variabilities (variation points) in the Scrum framework, along with the situations where a variation point can be resolved... 

This paper describes a new method for analyzing the bidding strategies of Generating Companies (GENCOs) in the Independent System Operator (ISO) point of view. ISO uses these results to detect the participants that have the potential for market power or actual exercise of market power. ISO models all GENCOs with perfect information. The proposed methodology uses the marginal cost of GENCOs as an initial point for bidding strategies of GENCOs and improves bidding strategies based on the objective function of GENCOs, the state of them in each hour of the day and with regard to ISO's market clearing problem. ISO tries to maximize the social welfare or minimize consumer's payments. The model... 

Analysis of multi dimensional interactions of flow of energy in passenger vehicle is a complex task that necessitates development and utilization of analytical tools. Development of analytical tools with high complexity is usually based on conclusions of many concepts and theories from different scientific disciplines. In this approach, Passenger vehicle is supposed to be organized in the form of a firm and appears in the market that oriented towards establishing an effective energy supply system which may be identified as delivering the product (person per mileage removable) with minimum operation costs. To this end, an optimization model named POWER software founded on theory of firm of... 

System fault-tree analysis is a technique for modeling dependability that is in widespread use. For systems such as embedded systems that include both hardware and software, the integration of hardware and software fault trees has proved problematic. In this paper, we present a method for reliability and safety analysis of embedded systems modeled by SystemC language. The evaluation is based on the fault trees generated from both hardware and software parts of the embedded systems described in the unified language. The unified modeling of both hardware and software of embedded systems using SystemC enables designers to be early aware from the safety and reliability of their designs more... 

Optical Character Recognition (OCR) softwares are widely used in the office automation systems. One of the first steps in the recognition of the documents is to segment the input image. Various methods have been offered for the English language. For the Persian/Arabic Language, however, no complete method has been found yet. In this paper we present a new page segmentation method for Persian/Arabic printed texts. This method has been inspired by the effect of the spreading of ink on paper. One of the most important characteristics of this method is its non-sensitivity to rotation