Sharif Digital Repository

This paper presents a new ADC based on using passive charge sharing SAR ADC in a 2-stage pipeline architecture. The charge domain operation of passive charge sharing ADC poses an inherent limitation on its resolution. The proposed architecture increases the achievable resolution with a low power overhead. Designed and simulated in a 0.18um CMOS process, the 12-bits, 40MS/sec ADC core consumes 7mW from a 1.8V supply  

The star graph, as an interesting network topology, has been extensively studied in the past. In this paper, we address some of the combinatorial properties of the star graph. In particular, we consider the problem of calculating the surface area and volume of the star graph, and thus answering an open problem previously posed in the literature. The surface area of a sphere with radius i in a graph is the number of nodes in the graph whose distance from a given node is exactly i. The volume of a sphere with radius i in a graph is the number of nodes within distance i from the given node. In this paper, we derive explicit expressions to calculate the surface area and volume in the star graph.... 

In this paper, the problem of the waveform design for colocated multiple-input multiple-output (MIMO) radars is considered in two parts. In the first part, we design transmit waveform in order to approximate the desired beampattern with low number of samples in the transmitter. Unlike the traditional waveform design methods, in our solution, waveforms are designed for a specific number of samples. Also, the constant envelope constraint that is an important practical constraint is considered. In the second part, we jointly design the transmit waveform and receive filter by a sequential algorithm, considering a priori information of target and interference angle locations. We have evaluated... 

In this paper, we use the regular distribution method to design a perfect load balancing algorithm for an n-star with a maximum error of 1 and a time complexity of 3n(n+1). This algorithm is based on the novel notion of leader trees. A second algorithm proposed in this paper as an enhancement to our first algorithm and uses an arbitrary spanning tree as the leader tree and has a worst time complexity of 2.25n 2-3n+0.75. We also discuss the issue of dynamically selecting the leader tree and hybrid load balancing algorithms in general. Furthermore, we present a hybrid algorithm for load balancing on the star interconnection network which benefits from a diffusion load balancing preprocessing... 

The star graph, as an interesting network topology, has been extensively studied in the past. In this paper, we address some of the combinatorial properties of the star graph. In particular, we consider the problem of calculating the surface area of the star graph, answering an open problem previously posed in [12]. © 2005 IEEE  

In this letter, we consider the problem of waveform design in colocated multiple-input multiple-output radars in order to obtain a desired beampattern. In this problem, practical constraints, such as constant envelope (CE) and low peak-to-average power ratio, are very important. Therefore, we propose a simple method to generate some practical waveforms, such as different versions of phase-shift keying and pulse-amplitude modulation. We map a non-CE to the desired finite alphabet by a mapping function (MP). In the proposed method, first, the values of cross-correlation relationship between the input and the output of MP are calculated in a few points, and then, using radial point... 

In this paper, using the chromatic properties of power graphs we propose a new approach for placing resources in symmetric networks. Our novel placement scheme guarantees a perfect placement when such a solution is feasible in the topology, while in general it answers the question of k-resource placement at a distance d where each non-resource node is able to access k resource nodes within at most d hops away. We define a quasi-perfect graph as a graph whose clique number and chromatic number are equal. We derive important properties of quasi-perfect graphs and use them to find a solution for the resource placement problem. We have also applied the proposed method to find a distant resource... 

As the use of superparamagnetic iron oxide nanoparticles (SPION) in biomedical applications increases (e.g. for targeting drug delivery and imaging), patients are likely to be exposed to products containing SPION. Despite their high biomedical importance, toxicity data for SPION are limited to date. The aim of this study is to investigate the cytotoxicity of SPION and its ability to change cell medium components. Bare and poly(ethylene glycol)-co-fumarate (PEGF)-coated SPION with narrow size distributions were synthesized. The particles were prepared by co-precipitation using ferric and ferrous salts with a molar Fe3+/Fe2+ ratio of 2. Dulbecco's modified Eagle's medium (DMEM) and primary... 

Superparamagnetic iron oxide nanoparticles (SPION) with narrow size distribution and stabilized by polyvinyl alcohol (PVA) were synthesized. The particles were prepared by a coprecipitation technique using ferric and ferrous salts with a molar Fe3+/Fe2+ ratio of 2. Using a design of experiments (DOE) approach, the effect of different synthesis parameters (stirring rate and base molarity) on the structure, morphology, saturation magnetization, purity, size, and size distribution of the synthesized magnetite nanoparticles was studied by various analysis techniques including X-ray powder diffraction (XRD), thermogravimetric analysis (TGA) with differential scanning calorimetry (DSC)... 

This paper introduces a new class of interconnection networks named star-pyramid. An n-level star-pyramid is formed by piling up star graphs of dimensions 1 to n in a hierarchy, connecting any node in each i-dimensional star, 1 < i ? n, to a node in the (i - 1)-dimensional star whose index is reached by removing the i symbol from the index of the former node in the i-dimensional star graph. Having extracted the properties of the new topology, featuring topological properties, a minimal routing algorithm, a simple but efficient broadcast algorithm, Hamiltonicity and pancyclicity, we then compare the network properties of the proposed topology and the well-known pyramid topology. We show that... 

This paper introduces a new class of interconnection networks named star-pyramid. An n-level star-pyramid is formed by piling up star graphs of dimensions 1 to n in a hierarchy, connecting any node in each i-dimensional star, 1 < i ≤ n, to a node in the (i - 1)-dimensional star whose index is reached by removing the i symbol from the index of the former node in the i-dimensional star graph. Having extracted the properties of the new topology, featuring topological properties, a minimal routing algorithm, a simple but efficient broadcast algorithm, Hamiltonicity and pancyclicity, we then compare the network properties of the proposed topology and the well-known pyramid topology. We show that... 

In this paper, we propose a new approach in computing interference distribution and outage probability for uplink CDMA cellular networks. In this approach, we model time-varying interference as a discrete-time Markov chain with flexible approximation and find its steady state distribution. Our approach is based on tracing the time variation of the effective factors in interference such as spatial locations, activity status, and shadowing status for the connected users. To this end, we approximate shadowing with several discrete levels by Lloyd algorithm. Moreover, we incorporate correlation properties of the shadowing status in our model. Then, we map the effective factors onto the... 

This paper introduces a new class of interconnection networks named Star-Pyramid, SP(n). A star-pyramid of dimension n is formed by piling up star graphs of dimensions 1 to n in a hierarchy, connecting any node in each i-dimensional star, 1< i ≤ n, to a node in (i - 1)-star whose index is reached by removing the i symbol from the index of the former node in the i-star graph. Having extracted the properties of the new topology, featuring topological properties, a simple routing algorithm and Hamiltonicity then we compare the network properties of the proposed topology and the well-known pyramid topology. We show that the star-pyramid is more fault-tolerant and has less network diameter than... 

The possibility of photonuclear transmutation of 93Zr, a highly radioactive nuclear waste with a half-life of 1.53 million years, into 92Zr its stable isotope, through a (γ, n) reaction has been analytically evaluated in this paper. By focusing Intensities more than 1020 W/cm2 onto a solid target, high energy electron generation, Bremsstrahlung and photonuclear reactions have been observed. Using the available data, the number of reactions that produced 92Zr, have been analytically calculated. In addition, this work has shown that the laser intensity, irradiation time and repetition rate of laser have strong and direct effects on the yield of 92Zr and the number of reactions. Irradiating a... 

For risk free application of nanoparticles in life science, energy and the environment, it is essential to understand their biological fate and potential toxicity. The application of iron oxide nanoparticles for drug delivery has been one of the most promising researches in the field of nanotechnology. However, there are two major problems associated with magnetically targeted deliveries that still need close attention: • As the drug is coated on to the particle surfaces, there is the possibility of faster drug release (Burst Effect). Therefore, after reaching to the specific site, there is very low amount of drug for delivery. To overcome this problem, some researchers have used conjugation... 

In recent years, the construction of high-rise buildings as an urban development strategy has been accepted in many megacities. High-rise buildings have positive as well as negative impacts on urban environments. Therefore, the environmental impact assessment of high-rise buildings for establishing strategies to ensure sustainable and resilient urban development is essential. In this study, the environmental impact of high-rise buildings with a resilient development mindset was assessed. Resilience mindset provides an approach for including the uncertainties and interdependence of systems and processes for planning new sustainable developments and assessment methods. The corresponding... 

Superparamagnetic iron oxide nanoparticles (SPIONs) are promising materials for various biomedical applications including targeted drug delivery and imaging, hyperthermia, magneto-transfections, gene therapy, stem cell tracking, molecular/cellular tracking, magnetic separation technologies (e.g. rapid DNA sequencing), and detection of liver and lymph node metastases. The most recent applications for SPIONs for early detection of inflammatory, cancer, diabetes and atherosclerosis have also increased their popularity in academia. In order to increase the efficacy of SPIONs in the desired applications, especial surface coating/characteristics are required. The aim of this article is to review...