A new approach for constrained chaos synchronization with application to secure data communication

In this paper, a new technique is introduced for chaos secure data communication. In this approach, in addition to the usually used techniques for data encryption, the concept of carrier encryption is introduced to increase the security level of the secure communication scheme. To fulfill this objective, at the transmitting end, two chaotic oscillators are coupled, and a set of inequality time dependent constraints with time dependent bounds is imposed on the generated chaotic signals. Moreover, to increase system complexity and its security level, the imposed set of constraints and their bounds are allowed to be changeable from one time period to another during the transmission process. As a result, the patterns of the generated chaotic signals are completely changed and the chaotic oscillator is completely encrypted. At the receiving end, the newly developed Constrained Smoothed Regularized Least Square (CSRLS) observer is used to synchronize the received constrained chaotic signals and hence retrieve the transmitted data. Using such an approach, the quality of the received information, measured by the Bit Error Rate (BER), is highly improved due to the superior performance of the developed CSRLS observer. The stability of the observer is analyzed, and simulation results are presented to show the efficiency and effectiveness of the proposed secure communication scheme.     

Association of Prooxidant–Antioxidant Balance with Clinical and Laboratory Parameters and Its Relation to Different Drug Regimens in Polycystic Ovary Syndrome Women with Normal BMI

Polycystic ovarian syndrome is one of the most common hormonally leading cause infertility disorders. The effect of oxidant-antioxidant imbalance on disease progression has been studied in many disorders. The present study was aimed to evaluate prooxidant–antioxidant balance (PAB) in patients with polycystic ovarian syndrome compared to healthy subjects. We also studied the possible effect of treatment with available drugs on serum PAB. In this case–control study 100 polycystic ovary syndrome (PCOS) patients and 100 healthy individuals were enrolled in the study. The laboratory features of patients and controls like as serum LH and FSH concentration and hematological examinations were collected. PAB was evaluated by a colorimetric method. Serum PAB value was significantly higher before treatment compared to after treatment and healthy subjects. PAB values were also higher in subjects with irregular menstrual cycle compared to normal subjects. Our results represented that serum PAB values has an indirect significant correlation with serum LH concentration. We also found that drugs regimen containing spironolactone effectively reduced the serum PAB values. Our results showed that PCOS patients had increased level of PAB and treatment with spironolactone mainly decreases the level of serum PAB. Our results indicate that the measurements of PAB may be used as a potential laboratory marker for assessment of PCOS patients.     

Beneficial Effect of Aqueous Garlic Extract on Inflammation and Oxidative Stress Status in the Kidneys of Type 1 Diabetic Rats

One of the most important complications of diabetes is nephropathy. This study investigates the effects of aqueous garlic extract on inflammation and oxidative stress status in the kidneys of diabetic rats. Male rats were divided into four groups- control rats, diabetic rats, garlic extract-treated diabetic rats, garlic extract-treated normal rats. The glucose, urea, uric acid, and creatinine levels were measured in sera using colorimetric methods. To determine the oxidative stress condition in the kidney tissues, total antioxidant capacity (TAC), malondialdehyde (MDA), and total oxidant status (TOS) were measured using colorimetric methods. Inflammation status was evaluated by the determination of tumor necrosis factor-alpha (TNF-α) gene and protein expression using qRT-PCR and ELISA respectively, while nitric oxide (NO) level in these tissues was measured using the Griess method. Histological examination of Kidneys was carried out by H&E staining. The levels of glucose, urea, and uric acid were found to increase in the serum of diabetic rats and decrease in that of diabetic rats after treatment with garlic. Measurement of MDA, TOS, and TAC revealed oxidative stress in diabetic rats, which improved after receiving the extract. The NO and TNF-α protein levels in diabetic rats were higher than those in control rats. After treatment with garlic, the levels of TNF-α protein and NO became close to the normal levels. Histological results confirmed certain other data as well. Garlic has antioxidant properties; therefore, it can reduce oxidative stress, which plays an important role in the development of diabetic nephropathy. Reduction in oxidative stress has beneficial effects on inflammation because it leads to a decrease in the level of TNF-α.     

Robust simultaneous fault detection and control for a class of nonlinear stochastic switched delay systems under asynchronous switching

This paper concerns the simultaneous fault detection and control (SFDC) problem for a class of nonlinear stochastic switched systems with time-varying state delay and parameter uncertainties. The switching signal of detector/controller unit (DCU) is assumed to be with switching delay, which results in the asynchronous switching between the subsystems and DCU. By constructing a switching strategy depending on the state and switching delays, new sufficient conditions expressed by a set of linear matrix inequalities (LMIs) is derived to design DCU gains. This problem is formulated as an H_∞ optimization problem and both mean square exponential stability and fault detection of augmented system are considered. A numerical example is finally exploited to verify the effectiveness and potential of the achieved scheme.     

An Ethnographic Study of the Computational Strategies of a Group of Young Street Vendors in Beirut

This study examines the computational strategies of ten young street vendors in Beirut by describing, comparing, and analyzing the computational strategies used in solving three types of problems in two settings: transactions in the workplace, word problems, and computation exercises in a school-like setting. The results indicate that vendors' use of semantically-based mental computational strategies was more predominant in transactions and word problems than in computation exercises whereas written school-like computational strategies were used more frequently in computation exercises than in word problems and transactions. There was clear evidence of more effective use of logico-mathematical properties in transactions and word problems than in computation exercises. Moreover, the success rate associated with each of transactions and word problems was much higher than that associated with computation exercises.This revised version was published online in September 2005 with corrections to the Cover Date.     

非政府组织在天文学科普方面的作用

古代伊朗科学家曾对科学,特别是天文学做出过重大贡献。当代的伊朗科学家继承了这一传统,并致力于向公众传播科学。21世纪初,由一批科学家、热心科学传播的社会人士和私营企业组成的非政府组织积极筹建马什哈德天文馆、科学中心等科普场馆。本文通过这一案例,讨论了非政府组织在科普场馆建设和科学传播中的作用、问题和可行性,并介绍了马什哈德天文学会为此采取的相应对策。     

An evaluation of information behaviour studies through the Scholarly Capital Model

Influence and capital are two concepts used to evaluate scholarly outputs, and these can be measured using the Scholarly Capital Model as a modelling tool. The tool looks at the concepts of connectedness, venue representation, and ideational influence using centrality measures within a social network. This research used co‐authorships and h‐indices to investigate authors who have published papers in the field of information behaviour between 1980 and 2015 as extracted from Web of Science. The findings show a relationship between the authors’ connectedness and the venue (journal) representation. It could be seen that the venue (journal) influences the chance of citation, and equally, the prestige (centrality) of authors probably raises the citations of the journals. The research also shows a significant positive relationship between the venue representation and ideational influence. This means that a research work that is published in a highly cited journal will find more visibility and will receive more citations.     

AFAR: adaptive fuzzy ant-based routing for communication networks

We propose a novel approach called adaptive fuzzy ant-based routing （AFAR）, where a group of intelligent agents （or ants） builds paths between a pair of nodes, exploring the network concurrently and exchanging obtained information to update the routing tables. Routing decisions can be made by the fuzzy logic technique based on local information about the current network state and the knowledge constructed by a previous set of behaviors of other agents. The fuzzy logic technique allows multiple constraints such as path delay and path utilization to be considered in a simple and intuitive way. Simulation tests show that AFAR outperforms OSPF, AntNet and ASR, three of the currently most important state-of-the-art algorithms, in terms of end-to-end delay, packet delivery, and packet drop ratio. AFAR is a promising alternative for routing of data in next generation networks.     

Information Needs: Developing Personas of Humanities Scholars

A persona represents a group of target users that share common behavioural characteristics. The personas method, an approach to systems design, has been receiving significant attention from practitioners. However, only anecdotal evidence currently exists for the effectiveness of personas and there have been criticisms about its validity as a scientific approach to research. This paper attempts to demonstrate how incorporating personas may lead to better understand the information needs of humanities scholars. Humanities scholars in an advanced ICT environment in the Hashemite Kingdom of Jordan are sampled as a case. Previous studies show that the humanities scholars have a significant negative relation with ICT use; they are using it less than scientists and social scientists, and they demonstrate a significantly higher use of library facilities than other academics. There is also a lack of up-to-date international research on the humanities scholars' information needs that takes into account recent rapid increases in the availability of ICT infrastructure, especially the Internet. As such, the objective of this study is to understand the information needs of humanities scholars and the effect of the electronic environment on their information seeking behaviour using personas. This study is conducted within a conceptual framework based on an integration of existing models of information-seeking behaviour, along with additional new elements representing the information context environment, such as languages, decision to seek and format of information resources. The four personas that were uncovered in this study may be able to effectively communicate the actual information needs of the humanities scholars through the personal narrative, name, and face, which continuously will remind the academic library of what their users really want and need from their services. This study also lays the foundation for future research by identifying variables of interest, and building construct validity through the themes of information needs that emerged.     

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 %).