Development of Java based RFID application programmable interface for heterogeneous RFID system

Developing RFID based applications is a painstakingly difficult endeavor. The difficulties include non-standard software and hardware peripherals from vendors, interoperability problems between different operating systems as well as lack of expertise in terms of low-level programming for RFID (i.e. steep learning curve). In order to address these difficulties, a reusable RFIDTM API (RFID Tracking & Monitoring Application Programmable Interface) for heterogeneous RFID system has been designed and implemented. The API has been successfully employed in a number of application prototypes including tracking of inventories as well as human/object tracking and tagging. Here, the module has been tested on a number of different types and configuration of active and passive readers including that LF and UHF Readers.     

Study of generalized delay-timers in alarm configuration

In process plants, alarms are configured to notify operators of any abnormalities or faults. However, in practice a majority of raised alarms are false or nuisance and create problems for operators as they face an increasing number of alarms to handle. Adding delay-timers is a simple technique that can reduce this problem and is widely exercised in industry. In this work we propose a generalized delay-timer framework where instead of consecutive n samples in the conventional case, n₁ out of n consecutive samples (n₁ ≤ n) are considered to raise an alarm. For the generalized delay-timer, three important performance indices, namely, the false alarm rate (FAR), the missed alarm rate (MAR) and the expected detection delay (EDD), are calculated using Markov processes. Moreover, the performance and sensitivity of generalized delay-timers are compared with conventional delay-timers.     

Mesoscale eddies and variability of chlorophyll-a in the Sea of Oman

Satellite-derived (TOPEX/Poseidon, Jason-1, Jason-2, SeaWIFS (Sea-Viewing Wide Field-of-View Sensor) and MODIS (Moderate Resolution Imaging Spectroradiometer) Aqua) weekly and monthly products for sea surface height, sea surface temperature (SST) and chlorophyll-a (CHL) concentration were used to analyse the trends of physical–biological coupling. In the variability of chlorophyll, no interannual trends were found for the Sea of Oman (1997–2008). However, the variation of chlorophyll within the annual cycle has increased. A similar tendency was evaluated for the variability of the energy of mesoscale eddies. The median level of kinetic energy and the coefficient of variation of this energy within the annual cycle both increased from 1997 through 2008.     

Movement-Assisted Connectivity Restoration in Wireless Sensor and Actor Networks

Recent years have witnessed a growing interest in applications of wireless sensor and actor networks (WSANs). In these applications, a set of mobile actor nodes are deployed in addition to sensors in order to collect sensors' data and perform specific tasks in response to detected events/objects. In most scenarios, actors have to respond collectively, which requires interactor coordination. Therefore, maintaining a connected interactor network is critical to the effectiveness of WSANs. However, WSANs often operate unattended in harsh environments where actors can easily fail or get damaged. An actor failure may lead to partitioning the interactor network and thus hinder the fulfillment of the application requirements. In this paper, we present DARA, a Distributed Actor Recovery Algorithm, which opts to efficiently restore the connectivity of the interactor network that has been affected by the failure of an actor. Two variants of the algorithm are developed to address 1- and 2-connectivity requirements. The idea is to identify the least set of actors that should be repositioned in order to reestablish a particular level of connectivity. DARA strives to localize the scope of the recovery process and minimize the movement overhead imposed on the involved actors. The effectiveness of DARA is validated through simulation experiments.     

Al-Alaoui operator and the new transformation polynomials for discretization of analogue systems

The “new transformation polynomials for discretization of analogue systems” was recently introduced. The work proposes that the discretization of 1/s ⁿ should be done independently rather than by raising the discrete representation of 1/s to the power n. Several examples are given in to back this idea. In this paper it is shown that the “new transformation polynomials for discretization of analogue systems” is exactly the same as the parameterized Al-Alaoui operator. In the following sections, we will show that the same results could be obtained with the parameterized Al-Alaoui operator. This research was supported, in part, by the University Research Board of the American University of Beirut.     

Dealing with fuzziness in active mobile database systems

Current needs of industry required the development of advanced database models like active mobile database systems. An active mobile database system can be designed by incorporation of triggering rules into a mobile computing environment in which the users are able to access a collection of database services using mobile and non-mobile computers at any location. Fuzzy concepts are adapted to the field of databases in order to deal with ambiguous, uncertain data. Fuzziness comes into picture in active mobile databases especially with spatial queries on moving objects. Incorporating fuzziness into rules would also improve the effectiveness of active mobile databases as it provides much flexibility in defining rules for the supported application. In this paper we present some methods to adapt the concepts developed for fuzzy systems to active mobile databases.     

A new coefficient estimation method for autoregressive systems using cumulants

Autoregressive (AR) system identification with only output measurements is a well‐known problem in various science and engineering areas such as spectral estimation and speech processing. This paper addresses the problem of estimating the coefficients of an AR model from third‐order cumulants of the noisy observations of the system output. The system is driven by a zero‐mean independent and identically distributed (i.i.d) non‐Gaussian sequence. The input sequence is not observed. Simulation results are presented that demonstrate the performance of the new approach and compare it with a recently developed technique. Copyright © 2001 John Wiley & Sons, Ltd.     

Dynamic Modelling and Stability Analysis of Model-Scale Helicopters Under Wind Gust

The purpose of this paper is to present the stabilization (tracking) with motion planning of a reduced-order model having 3 Degrees Of Freedom (DOF). This last one represents a scale model helicopter mounted on an experimental platform. It deals with the problem of disturbance reconstruction acting on the autonomous helicopter, the disturbance consists in vertical wind gusts. The objective is to compensate these disturbances and to improve the performances of the control. Consequently, a nonlinear simple model with 3DOF of a helicopter with unknown disturbances is used. Three approaches of robust control are compared via simulations: a robust nonlinear feedback control, an active disturbance rejection control based on a nonlinear extended state observer and backstepping control.     

Prediction of Bank Erosion in a Reach of the Sacramento River and its Mitigation with Groynes

The paper reports on the prediction of flow in a reach of the Sacramento River with focus on a part of the river’s bank where serious erosion has occurred. The simulations were obtained using a three-dimensional Navier–Stokes solver which utilized body-fitted coordinates to represent the complex river bathymetry. Comparative predictions were obtained using a two-dimensional, depth-averaged formulation. Local (nested) mesh refinement was employed to provide the necessary resolution of the bank geometry in the region of interest. The study focuses on the assessment of the effectiveness of a particular arrangement of groynes which was found in physical model studies to significantly reduce the rate of erosion in the region under consideration. To validate the computational models, predictions were first obtained for the case of turbulent flow in a straight rectangular channel with one groyne. Measurements of velocity and boundary shear stress were used for model validation. For the reach of the Sacramento River under consideration, velocity measurements obtained in the large-scale physical model were also used to check the computational model prior to its use for prediction of the river flow with groynes. Here, too, both depth-averaged and three-dimensional computations were performed with the objective being to determine the influence of the groynes on the flow velocity. The bank erosion rate was estimated by coupling the ‘excess shear stress’ method to the computed mean velocity field. The results show that for the groynes configuration that was found optimal in the physical-model studies, and that was actually implemented in the Sacramento River, the groynes are effective in reducing the bank erosion of the affected zone but at the cost of transferring a far less severe problem further downstream.     

Improving the viability of Bifidobacterium bifidum BB-12 and Lactobacillus acidophilus LA-5 in white-brined cheese by microencapsulation

The viability of Bifidobacterium bifidum BB-12 and Lactobacillus acidophilus LA-5 microencapsulated by either an extrusion or an emulsion technique and used in white-brined cheese was monitored. Both microencapsulation techniques were effective in keeping the numbers of probiotic bacteria higher than the level of the therapeutic minimum (>10⁷ cfu g^?1). While the counts of probiotic bacteria decreased approximately 3 log in the control cheese in which probiotics were used as free cells, the decrease was more limited in the cheeses containing microencapsulated cells (approximately 1 log). Medium- and long-chain free fatty acid contents of the cheeses with immobilized probiotics were much higher than in the control cheese. Similarly, cheeses made with immobilized probiotics contained higher acetaldehyde and diacetyl levels than the control. Experimental cheeses containing microencapsulated probiotics were not different from the control cheese in terms of sensory properties.