Sharif Digital Repository

In this paper, sustainability with respect to transportation sector of the selected countries has been evaluated. Seventy nine countries were initially selected for detailed analysis for the period of 1980-1995. The key dimensions of sustainable development i.e. social, environmental, and economic characteristics are used. Firstly, a set of sustainable transportation indicators has been introduced. Then composite indices of three non-transport groups with respect to four transport modes are calculated. The composite indices are aggregated by the concordance analysis technique to achieve comprehensive transport sustainability indices of countries, and according to these values, the countries... 

In this paper we analyse two variants of SIMON family of light-weight block ciphers against variants of linear cryptanalysis and present the best linear cryptanalytic results on these variants of reducedround SIMON to date. We propose a time-memory trade-off method that finds differential/ linear trails for any permutation allowing low Hamming weight differential/ linear trails. Our method combines low Hamming weight trails found by the correlation matrix representing the target permutation with heavy Hamming weight trails found using a Mixed Integer Programming model representing the target differential/linear trail. Our method enables us to find a 17-round linear approximation for SIMON-48... 

This study tries to characterize national transportation modes to assess balancing and sustainability. Using a pioneer measure for sustainable development (SD), and based on the conformity of the growths of all sectors with transportation modes, the countries are comparatively studied. The proposed measure, elasticity, for each pair of variables indicates the extent to which the two variables have been changing consistently. Indeed the elasticity values are measures of "harmonic development" reflecting sustainability. The study database consisted of key aspects of transportation sustainability in the form of national variables including transportation, economic, social and environmental... 

Information and Communication Technologies (ICTs) are now widely accepted by developing countries as a critical tool in their efforts, so policy makers should develop ICT policies or e-policies in order to monitor and evaluate political, socio-economic and cultural impacts of ICT and also measure progress in the use of ICTs to achieve the development strategies and policies. The paper focuses on the ICT's impacts as an important part in developing e-policies, including a comprehensive model based on system approach, appropriate frameworks for determining affecting and affected elements of ICT and a conceptual framework for analyzing and prioritizing different dimensions of the society. The... 

This paper assesses the cycles and indices of drought in Iran and prepares general maps of the region, which are affected by droughts with 10- and 30-year reversible periods frequency of 1 and 3 years by utilizing statistical methods. To study the condition of drought, some indices have been applied in Yazd Province over a 48-year statistical period (1925-2000). Then with regard to existing statistics (1998-2001), the effect of drought on various issues during the most recent drought cycle have been assessed. © 2005 Taylor & Francis  

Treating cancer encompasses many invasive procedures that can be a source of distress in oncology patients. Distress itself can be a major obstruction in the path of acceptance of treatment and the patient's adaptation to it, thereby reducing its efficiency. These distress symptoms have been found to be prevalent in children suffering from cancer, in a spectrum from mild to critical. In the past years in response to this psychological suffering, researchers have proposed and tested several methods such as relaxation, hypnosis, desensitization, and distraction. This paper propounds a new approach by exploring the effect of utilizing a humanoid robot as a therapy-assistive tool in dealing with... 

For a simple polygon P of size n, we define weak visibility counting problem (WVCP) as finding the number of visible segments of P from a query line segment pq. We present different algorithms to compute WVCP in sub-linear time. In our first algorithm, we spend O(n7) time to preprocess the polygon and build a data structure of size O(n6), so that we can optimally answer WVCP in O(logn) time. Then, we reduce the preprocessing costs to O(n4+ε) time and space at the expense of more query time of O(log5n). We also obtain a trade-off between preprocessing and query time costs. Finally, we propose an approximation method to reduce the preprocessing costs to O(n2) time and space and O(n1/2+ε) query... 

This study aimed to examine the effect of robot assisted language learning (RALL) on the anxiety level and attitude in English vocabulary acquisition amongst Iranian EFL junior high school students. Forty-six female students, who were beginners at the age of 12, participated in this study and were randomly assigned into two groups of RALL (30 students) and non-RALL (16 students). The textbook, the materials, as well as the teacher were the same in the two groups. However in the RALL group, the treatment was given by a teacher accompanied by a humanoid robot assistant. Two questionnaires of anxiety and attitude were utilized to measure the students’ anxiety and attitude (Horwitz et al. 1986;... 

Privacy preservation is an important issue in data publishing. Existing approaches on privacy-preserving data publishing rely on tabular anonymization techniques such as k-anonymity, which do not provide appropriate results for aggregate queries. The solutions based on graph anonymization have also been proposed for relational data to hide only bipartite relations. In this paper, we propose an approach for anonymizing multirelation constraints (ternary or more) with (t,k) hypergraph anonymization in data publishing. To this end, we model constraints as undirected hypergraphs and formally cluster attribute relations as hyperedge with the t-means-clustering algorithm. In addition,... 

The secrecy problem in the state-dependent cognitive interference channel is considered in this paper. In our model, there are a primary and a secondary (cognitive) transmitter–receiver pairs, in which the cognitive transmitter has the message of the primary one as side information. In addition, the channel is affected by two channel state sequences, which are known at the cognitive transmitter and the corresponding receiver, separately. The cognitive transmitter should cooperate with the primary one, and it wishes to keep its message secure at the primary receiver. The achievable equivocation-rate regions for this channel are derived using two approaches: the binning scheme coding and... 

Over the last decades quota violations have become a norm for OPEC countries. However, the academic literature on OPEC focuses more on its production behavior than on analyzing the quota allocation process or characterizing quota violation patterns. This paper offers a theoretical model with empirical evidence to explain OPEC members’ incentives for abiding or violating quotas. We first offer a cartel model with a quota allocation rule and an endogenous capacity choice. The model highlights the trade-off between building spare capacity to bargain for a higher legitimate quota versus risking quota violation punishment. Using the quarterly data from 1995 to 2007, we empirically support the... 

The main security service in the connected world of cyber physical systems necessitates to authenticate a large number of nodes privately. In this paper, the private authentication problem is considered, that consists of a certificate authority, a verifier, many legitimate users (prover) and any arbitrary number of illegitimate users. Each legitimate user wants to be authenticated (using his personal key) by the verifier, while simultaneously wants to stay completely anonymous (even to the verifier and the CA). On the other hand, an illegitimate user must fail to authenticate himself. We analyze this problem from an information theoretical perspective. First, we propose a general interactive... 

In this paper, the relation between gain and resolution of an ideal analog optical differentiator in two different cases and their fundamental limits are investigated. Based on this relation, a figure of merit for comparison of the designed differentiators in recent papers is proposed. The differentiators are optimized using this figure of merit, and they are compared with each other to determine the best one. Also, a new differentiator is presented based on the dielectric slab waveguide in which the trade-off between its gain and resolution is easily controllable, and its best operating point is determined. © 2020 Optical Society of America under the terms of the OSA Open Access Publishing... 

We consider the anonymous mutual authentication problem, which consists of a certificate authority, single or multiple verifiers, many legitimate users (provers) and any arbitrary number of illegitimate users. The legal verifier and a legitimate user must be mutually authenticated to each other using the user's key, while the identity of the user must stay unrevealed. An attacker (illegitimate prover) as well as an illegal verifier must fail in authentication. A general interactive information theoretic framework in a finite field is proposed, where the normalized total key rate as a metric for reliability is defined. Maximizing this rate has a trade-off with establishing anonymity. The... 

Optimal allocation of resources for R&D on new energy technologies is an important issue in the process of development of energy system models. In this study, a model of R&D planning in energy sector has been developed and it is then linked to the energy system model. Energy system model is used as a tool for the technology assessment and prioritization of new energy technologies is evaluated with the help of this model. Based on the economic and environmental impact of new technologies, the optimal allocation of resources for R&D of new technology is estimated with the help of the R&D planning model. The conceptual formulation of the model and its integration with the energy technology... 

We consider the effect of caching in wireless networks where fading is the dominant channel effect. First, we propose a one-hop transmission strategy for cache-enabled wireless networks, which is based on exploiting multi-user diversity gain. Then, we derive a closed-form result for throughput scaling of the proposed scheme in large networks, which reveals the inherent trade-off between cache memory size and network throughput. Our results show that substantial throughput improvements are achievable in networks with sources equipped with large cache size. We also verify our analytical result through simulations  

A new algorithm for learning jointly reconstructive and discriminative dictionaries for sparse representation (SR) is presented. While in a usual dictionary learning algorithm like K-SVD only the reconstructive aspect of the sparse representations is considered to learn a dictionary, in our proposed algorithm, which we call K-LDA, the discriminative aspect of the sparse representations is also addressed. In fact, K-LDA is an extension of K-SVD in the case that the class informations (labels) of the training data are also available. K-LDA takes into account these information in order to make the sparse representations more discriminate. It makes a trade-off between the amount of... 

A method to design a tunable low noise amplifier (LNA) for multiband receivers is proposed. This paper also presents a single-ended to differential conversion (S2DC) topology which improves the LNA linearity without degrading its noise performance. Combining input tuning with S2DC in a single stage reduces power consumption of the LNA and decreases effects of supply noise. An LNA has been designed based on the proposed method for 2.3-4.8 GHz in a 0.18 μm CMOS technology. Simulations show an IIP3 of -3.2 dBm, a less than 3.7 dB noise figure (NF), a voltage gain of 24 dB in the whole frequency range. The LNA draws 13.1 mW from a 1.8 V supply. The results indicate that the proposed tuning... 

The spread of influence in social networks is studied in two main categories: progressive models and non-progressive models (see, e.g., the seminal work of Kempe et al. [8]). While the progressive models are suitable for modeling the spread of influence in monopolistic settings, non-progressive models are more appropriate for non-monopolistic settings, e.g., modeling diffusion of two competing technologies over a social network. Despite the extensive work on progressive models, non-progressive models have not been considered as much. In this paper, we study the spread of influence in the non-progressive model under the strict majority threshold: given a graph G with a set of initially... 

Recommender systems are in the center of network science, and they are becoming increasingly important in individual businesses for providing efficient, personalized services and products to users. Previous research in the field of recommendation systems focused on improving the precision of the system through designing more accurate recommendation lists. Recently, the community has been paying attention to diversity and novelty of recommendation lists as key characteristics of modern recommender systems. In many cases, novelty and precision do not go hand in hand, and the accuracy-novelty dilemma is one of the challenging problems in recommender systems, which needs efforts in making a...