Barriers of the development of web-based training in agricultural higher education system in Iran: A case study of Hamadan Bu Ali Sina University,Iran

Recently, higher education systems seek to use network-based and Internet-based information technologies in education, teaching and learning. E-learning in Iran higher education system has been started since 2003, however, its development has been very slow. The present study is a survey research. The participants of the study are faculty members, graduates and PhD students in Agriculture in Bu Ali Sina University. Total number of participants were analyzed (n?=?500). The accuracy of indicators and items in the questionnaire (face validity) has been confirmed by specialists. A questionnaire was used to collect data. Reliability was calculated by using Cronbach Alpha. In this study, Factor analysis is used to achieve the key factors. The results show that deficiency of executives, lack of learners’ motivation, infrastructural barriers, restriction of credit, and software and hardware limitations are the main problems in the development of web-based training. At the end of the article, some recommendations are presented aiming to accelerate electronic training in Iran’s higher education system.     

Israeli public diplomacy toward the United States: a network and narrative approach

Israel’s public diplomacy efforts in the U.S. are aimed at garnering American public support for Israeli foreign policy. This study aims to identify the networks of Israeli public diplomacy toward the United States. Using the theoretical frameworks of networked public diplomacy and strategic narrative, the authors try to understand how network strategy is used and information is circulated to create a strategic narrative. Therefore, the two methods of social network analysis and qualitative content analysis are applied to identify the networks of Israeli public diplomacy in the United States and the content produced by it. The study finds that in Israel’s public diplomacy model, the networking method stands in contrast to its government-oriented strategic narrative. Thus, new forms of communication are applied to conduct old strategies. The research identifies four types of actors who apply new public diplomacy techniques and dissects the strategic narrative they employ to affect the American public in the service of Israeli interests. Despite the effort to apply new forms of public diplomacy, strategic narrative production and dissemination remain highly governmental and closed, which is indicative of the persistence of old forms of public diplomacy.     

Symmetry properties of tetraammine platinum(II) with C_(2v) and C_(4v) point groups

INTRODUCTION The simplicity and elegance of some of theapplications of graph theory to chemistry can perhapsonly be compared with the results from group theorydealing with symmetry as a basic quality of a system.In some problems connectivity and symmetry arecombined and the question of determining symmetryproperties of graph becomes important. Given here are some definitions and notations.An automorphism of a graph G is a permutation g ofthe vertex set of G with the property that, for an…     

A sliding mode approach to H∞ synchronization of master–slave time-delay systems with Markovian jumping parameters and nonlinear uncertainties

In this paper, a sliding-mode approach is proposed for exponential H_∞ synchronization problem of a class of master–slave time-delay systems with both discrete and distributed time-delays, norm-bounded nonlinear uncertainties and Markovian switching parameters. Using an appropriate Lyapunov–Krasovskii functional, some delay-dependent sufficient conditions and a synchronization law, which include the master–slave parameters are established for designing a delay-dependent mode-dependent sliding mode exponential H_∞ synchronization control law in terms of linear matrix inequalities. The controller guarantees the H_∞ synchronization of the two coupled master and slave systems regardless of their initial states. Two numerical examples are given to show the effectiveness of the method.     

Estimation of the range of energy flow

The paper relates the power engineering problem of the extremal values of effective energy flow to a well established branch of mathematics; namely, the spectral analysis of linear operators. Variation of the effective energy flow in a linear time-invariant power distribution system is studied in the light of numerical range of the operator representing the system [Eqs. (18, 19)]. A knowledge of this range and its extremal values depends on the evaluation of eigenvalues and eigenvectors of a complex network function. In most cases an exact evaluation is practically unattainable (Section V). Simple and practical estimations of the energy dissipation range are presented. The novel spectral approach to energy problems may hopefully find useful applications in power transmission and distribution.     

Convexity of the Energy Domain

A basic theorem describing the convexity of the energy domain for the general family of linear time-invariant (active or passive, reciprocal or non-reciprocal, lumped or distributed, single variable or multivariable) physical system {T} is proved.Theorem: Let F = P + jQ represent the complex energy associated with any linear physical system T (n-port). For any specified excitation of frequency s and the family of constant energy content input signals {i:∥i∥= constant}, the point F describes a convex domain in the {P;Q} plane.Part I contains a mathematical and a network theoretic proof of the foregoing theorem. In Part II the geometric nature of the energy loci for the two-ports is examined. It is shown that for all two-ports with double eigenvalves the energy domain is circular. For two-ports with distinct eigenvalves, the convex energy domain is an ellipse. The geometric characterization of this elliptic domain is examined and examples verified by computer.The concept of convexity is frequently exploited in optimization of energy in electric power system and quadratic cost functions in control theory. In this respect the central theorem of this paper, its proof and geometric ramifications should prove to be of basic interest for all linear systems.     

Angular region: a measure of underdamped behavior

The natural modes of an underdamped dynamical system are given by the characteristic numbers of the quadratic operator pencil

$\text{P(s)=s}{}^2\text{I+sB+A,}$

where the operator A depends on the dissipative and reactive elements of the system, while B depends solely on the reactive elements. The operator P(s) for every applied stimulus vector signal x must satisfy:

$\text{(Bx,x)}{}^2\text{<4(Ax,x).}$

A measure of underdamped behaviour is suggested by predetermining an angular region |φ| containing all natural modes of the system,

$\text{|}\text{tan}\text{φ|?}\text{[4(Ax,x)?(Bx,x)}{}^2\text{]}{}^{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{(Bx,x)}\text{.}$

When a comparison between positive operators A and B is available, say B²=KA, then

$\text{|}\text{tan}\text{φ|?}\text{√(4?K}{}^2\text{)}\text{K}\text{.}$

The paper is motivated by Duffin-Krein-Gohberg's earlier mathematical contributions.     

Defending recommender systems by influence analysis

Collaborative filtering (CF) is a popular method for personalizing product recommendations for e-commerce applications. In order to recommend a product to a user and predict that user’s preference, CF utilizes product evaluation ratings of like-minded users. The process of finding like-minded users forms a social network among all users and each link between two users represents an implicit connection between them. Users having more connections with others are the most influential users. Attacking recommender systems is a new issue for these systems. Here, an attacker tries to manipulate a recommender system in order to change the recommendation output according to her wish. If an attacker succeeds, her profile is used over and over again by the recommender system, making her an influential user. In this study, we applied the established attack detection methods to the influential users, instead of the whole user set, to improve their attack detection performance. Experiments were conducted using the same settings previously used to test the established methods. The results showed that the proposed influence-based method had better detection performance and improved the stability of a recommender system for most attack scenarios. It performed considerably better than established detection methods for attacks that inserted low numbers of attack profiles (20–25 %).     

Teacher-directed learning in view-independent face recognition with mixture of experts using single-view eigenspaces

We propose a new model for view-independent face recognition by multiview approach. We use the so-called “mixture of experts”, ME, in which, the problem space is divided into several subspaces for the experts, and the outputs of experts are combined by a gating network. In our model, instead of leaving the ME to partition the face space automatically, the ME is directed to adapt to a particular partitioning corresponding to predetermined views. To force an expert towards a specific view of face, in the representation layer, we provide each expert with its own eigenspace computed from the faces in the corresponding view. Furthermore, we use teacher-directed learning, TDL, in a way that according to the pose of the input training sample, only the weights of the corresponding expert are updated. The experimental results support our claim that directing the experts to a predetermined partitioning of face space improves the performance of the conventional ME for view-independent face recognition. In particular, for 1200 images of unseen intermediate views of faces from 20 subjects, the ME with single-view eigenspaces yields the average recognition rate of 80.51% in 10 trials, which is noticeably increased to 90.29% by applying the TDL method.