Evaluation of MODIS data for improved monitoring of the Caspian Sea

Moderate-Resolution Imaging Spectroradiometer (MODIS) optical and infrared data are used to monitor changes in the Caspian Sea coastline. The information extracted from MODIS images is converted into total water volume and mean lake level by combining a digital elevation model (DEM) with remote-sensing data. The elevation estimates were enhanced by reprocessing the MODIS data at the sub-pixel scale. The water volume variations estimated from MODIS data along with DEM are compared to other estimations derived from altimetry data sets, and show fair agreement.     

Manual materials handling capabilities in non-standard postures.

Research efforts to establish manual materials handling (MMH) capabilities of individuals and populations have been conducted for many years. Most of the previous efforts have explored 'standard postures', utilizing two-handed, symmetric, sagittal plane MMH using unrestricted postures. Recognizing that many industrial MMH activities do not utilize 'standard postures', recent research projects have explored psychophysically determined MMH capacities in a variety of non-standard postures. Among the non-standard postures examined were: twisting while lifting or lowering, lifting and lowering from lying, sitting, kneeling, and squatting positions, and carrying loads under conditions of constricted ceiling heights. This paper presents the results of a series of previous research efforts at Texas Tech University. The results are presented in the form of population capabilities of both males and females for 99 MMH tasks using 'non-standard postures'. The data tables contain means and standard deviations of the data, as well as percentile distributions for the subject populations. Sample sizes for the experimental populations ranged from 45 to 50 subjects of each sex in the first three experiments to 20 subjects of each sex in the fourth set of experiments.     

Joint block and stream cipher based on a modified skew tent map

Image encryption is very different from that of texts due to the bulk data capacity and the high redundancy of images. Thus, traditional methods are difficult to use for image encryption as their pseudo-random sequences have small space. Chaotic cryptography use chaos theory in specific systems working such as computing algorithms to accomplish dissimilar cryptographic tasks in a cryptosystem with a fast throughput. For higher security, encryption is the approach to guard information and prevent its leakage. In this paper, a hybrid encryption scheme that combines both stream and block ciphering algorithms is proposed in order to achieve the required level of security with the minimum encryption time. This scheme is based on an improved mathematical model to cover the defects in the previous discredited model proposed by Masuda. The proposed chaos-based cryptosystem uses the improved Skew Tent Map (STM) RQ-FSTM as a substitution layer. This map is based on a lookup table to overcome various problems, such as the fixed point, the key space restrictions, and the limitation of mapping between plain text and cipher text. It uses the same map as a generator to change the byte position to achieve the required confusion and diffusion effects. This modification improves the security level of the original STM. The robustness of the proposed cryptosystem is proven by the performance and the security analysis, as well as the high encryption speed. Depending on the results of the security analysis the proposed system has a better dynamic key space than previous ones using STM, a double encryption quality and a better security analysis than others in the literature with speed convenience to real-time applications.

     

Stability analysis of hybrid composite dynamical systems: Descriptions involving operators and differential equations

We address the stability analysis of composite hybrid dynamical feedback systems of the type depicted in Fig. 1, consisting of a block (usually the plant) which is described by an operatorLand of a finite-dimensional block described by a system of ordinary differential equations (usually the controller). We establish results for the well-posedness, attractivity, asymptotic stability, uniform boundedness, asymptotic stability in the large, and exponential stability in the large for such systems. The hypotheses of these results are phrased in terms of the I/O properties ofLand in terms of the Lyapunov stability properties of the subsystem described by the indicated ordinary differential equations. The applicability of our results is demonstrated by means of general specific examples (involving C0-semigroups, partial differential equations, or integral equations which determineL).     

A fast method for the determination of the efficiency coefficient of bare CR-39 detector

A fast and simple method for the determination of the efficiency coefficient (η) of bare CR-39 detector is presented and discussed. The efficiency coefficient of bare CR-39 detector is then calculated by different ways and the obtained values are found to be comparable to each other. The average value of η of bare CR-39 is found to be 0.20 ± 0.01 tracks cm⁻² day⁻¹ per Bq m⁻³.     

Bidirectional HMM-based Arabic POS tagging

In this work, we will present a new concept of POS tagging that will be implemented for the Arabic language. Indeed, we will see that in Arabic there are a numerous cases where the determination of the morpho-syntactic state of a word depends on the states of the subsequent words, which represents the theoretical foundation of the approach: how to consider, in addition of the past elements, the future ones. We will then demonstrate how the POS tagging in its statistical application: the HMM, is based mainly on the past elements, and how to combine both direct and reverse taggers to tag the same sequence of words in both senses. Thus, we will propose a hypothesis for the result selecting. In the practical part, we will present, in general, the used resource and the changes made on it. Then we will explain the experiment steps and the parameters collected and presented on graphics, that we will discuss later to lead to the final conclusion.     

Patient safety in outpatient surgery: the viewpoint of the healthcare providers

The objective of this study is to understand the viewpoint of healthcare providers with regard to patient safety in outpatient surgery settings. Two methods were used to gather data from the healthcare providers: (1) questionnaire with open-ended questions about six predefined stages of the patient care process; (2) survey with closed questions. With the first method, the main quality and safety of care issues concerned communication to patients, coordination of reports and forms, patient and staff time pressures and standards of care. The first two stages of the outpatient surgery process, i.e. patient work-up prior to day of surgery and patient admission and preparation on the day of surgery, yielded many more comments than the other four stages. The results of the structured questionnaire show that, overall, the healthcare providers report high quality of care provided by themselves (98%) and their surgery centre (96%). With regard to patient safety (i.e. cancellations of surgeries, patient safety problems and serious mistakes), there was a clear difference in perceptions reported by the physicians vs. the nurses and other staff. Nurses and other staff were more likely to report patient safety problems than physicians. The combination of qualitative data from the initial questionnaire and the quantitative data from the structured questionnaire provides a rather complete view of the outpatient surgery staff perceptions of quality and safety of care. This research highlights the importance of getting input from the healthcare providers regarding the quality and safety of care rather than relying only on traditional measures about patient outcomes.     

A Multi-Stage Secure IoT Authentication Protocol

The Internet of Things (IoT) is a network of heterogeneous and smart devices that can make decisions without human intervention. It can connect millions of devices across the universe. Their ability to collect information, perform analysis, and even come to meaningful conclusions without human capital intervention matters. Such circumstances require stringent security measures and, in particular, the extent of authentication. Systems applied in the IoT paradigm point out high-interest levels since enormous damage will occur if a malicious, wrongly authenticated device finds its way into the IoT system. This research provides a clear and updated view of the trends in the IoT authentication area. Among the issues covered include a series of authentication protocols that have remained research gaps in various studies. This study applies a comparative evaluation of authentication protocols, including their strengths and weaknesses. Thus, it forms the foundation in the IoT authentication field of study. In that direction, a multi authentication architecture that involves secured means is proposed for protocol authentication. Informal analysis can affect the security of the protocols. Burrows-Abadi-Needham (BAN) logic provides proof of the attainment of mutual authentication. NS3 simulator tool is used to compare the performance of the proposed protocol to verify the formal security offered by the BAN logic.     

Numerical simulation of tensile strength of upset welded joints with experimental verification

Resistance upset welding (UW) is a widely used process for joining metal parts. In this process current, time and upsetting force are three parameters that affect the quality of welded products. This paper considers numerical simulation and experimental investigation of UW process parameters. The investigated parameters include heating and post-weld heating current and their corresponding duration as well as interference of the part features that form the joint. In this study, evaluation of tensile strength of the welded joint with variation of the process parameters is also reported. For numerical analysis, a two-dimensional axisymmetric model using a coupled electro-thermal finite element method is developed to study the thermal behavior of the welded joints. The results of this numerical simulation are used to determine the status of the weldment and therefore evaluate the quality of the weld at the joint. Both numerical and experimental results suggest an optimum set of welding parameters, i.e. time and electrical current that yields a maximum value for the tensile strength of the joint. Also the effects of post-weld heating time and current on the tensile strength are evaluated and show that these parameters have a remarkable effect on improving tensile strength of the weldment.     

Simultaneous measurements of thermal conductivity and diffusivity of Se80Te20-xInx (x = 2, 4, 6 and 10) chalcogenide glasses at room temperature

Measurements of thermal conductivity and thermal diffusivity of twin pellets of Se₈₀Te_20-xIn_x (x = 2, 4, 6 and 10) glasses, prepared under a load of 5 tons were carried out at room temperature using transient plane source (TPS) technique. The measured values of both thermal conductivity and diffusivity were used to determine the specific heat per unit volume of the said materials in the composition range of investigation. Results indicated that both the values of thermal conductivity and thermal diffusivity increased with the addition of indium at the cost of tellurium whereas the specific heat remained almost constant. This compositional dependence behaviour of the thermal conductivity and diffusivity has been explained in terms of the iono-covalent type of bond which In makes with Se as it is incorporated in the Se-Te glass.