Optical Network Design for a Multiline-Rate Carrier-Grade Ethernet Under Transmission-Range Constraints

Ethernet is a success story in local area networks (LAN). Efforts for extending its boundaries beyond LAN to the carriers' backbone networks are in progress. We study the problem of designing reliable and cost-efficient high-rate (100 Gbit/s) carrier-grade Ethernet in a multiline-rate optical network under signal transmission-range constraints. Reliability is achieved using shared-path protection at the connection level (Ethernet tunnel in this study). We construct an auxiliary graph, called mixed topology (MT), using which it is possible to: 1) identify traffic grooming possibilities; 2) select a path which requires the minimum amount of 3R regeneration; and 3) effectively choose the data rate of the channel to be established. Our algorithms, tested on the 17-node German network, resulted in lower network cost and higher resource utilization compared with other schemes.     

Bond strength tests on deformed reinforcement in normal weight concrete

The primary aim of the research which is described in this paper was to investigate the effect of lateral pressure on the bond strength of deformed reinforcement set in normal weight concrete. A large number of tests was undertaken in which the main variables affecting bond strength were investigated. These included concrete strength, reinforcing bar diameter, concrete cover, lateral pressure, position of casting and bar spacing. A brief review of the small number of earlier investigations involving lateral pressures is provided. The paper provides details of the test specimens, the test apparatus and procedure, as well as typical results selected from approximately three hundred results. It draws conclusions on the appropriateness of the test method and the effects of the variables on the bond stress ratio and on bond strength.

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Résumé Le but principal de ces recherches était d'étudier l'effet de l'effort tranchant sur l'adhérence des armatures crantées placées dans du béton ordinaire. Un grand nombre d'essais ont été effectués pour étudier les principales variables qui influencent l'adhérence, y compris la résistance du béton, le diamètre des barres de renforcement, l'épaisseur d'enrobage, l'effort tranchant, la mise en place et le positionnement des barres. On résume le petit nombre de recherches antérieures sur ce sujet. L'article décrit les éprouvettes, l'appareillage et les procédures d'essais, ainsi que des résultats types choisis parmi environ 300 résultats d'essais. Il présente des conclusions sur l'applicabilité de la méthode d'essais et les effets des variables sur le rapport contrainte d'adhérence et sur l'adhérence.

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Editorial note Prof. Dr. P. E. Regan is a RILEM Senior Member and a member of the Editorial Group of TC 090-FMA, Fracture Mechanics of concrete-Applications.     

Production planning optimization with physical programming

This paper proposes an optimization-based model for production planning, and physical programming as an effective method to optimize the production planning process within this model's framework. This model seeks to minimize cost and manufacturing time, while maximizing production rate. The physical programming method is shown to offer an effective setting to address the conflicting nature of these objectives. A numerical example is provided, which illustrates the flexibility of such optimization-based models, and of this paper's model in particular. The ready inclusion of realistic production constraints and goals brings practical significance to this approach.     

Comparing the efficiency of artificial neural networks in sEMG-based simultaneous and continuous estimation of hand kinematics

Surface Electromyography (sEMG) plays a key role in many applications such as control of Human-Machine Interfaces (HMI) and neuromusculoskeletal modeling. It has strongly nonlinear relations to joint kinematics and reflects the subjects’ intention in moving their limbs. Such relations have been traditionally examined by either integrated biomechanics and multi-body dynamics or gesture-based classification approaches. However, these methods have drawbacks that limit their usability. Different from them, joint kinematics can be continuously reconstructed from sEMG via estimation approaches, for instance, the Artificial Neural Networks (ANNs). The Comparison of different ANNs used in different studies is difficult, and in many cases, impossible. The current study focuses on fairly evaluating four types of ANN over the same dataset and conditions in proportional and simultaneous estimation of 15 hand joint angles from 10 sEMG signals. The presented ANNs are Feedforward, Cascade-Forward, Radial Basis Function (RBFNN), and Generalized Regression (GRNN). Each ANN is applied to its special parametric study. All the methods efficiently solved the regression problem of the complex multi-input multi-output bio-system. The RBFNN has the best performance over the others with a 79.80% mean correlation coefficient over all joints, and its accuracy reaches as high as 92.67% in some joints. Interestingly, the highest accuracy over individual joints is 93.46%, which is achieved via the GRNN. The good accuracy suggests that the proposed approaches can be used as alternatives to the previously adopted ones and can be employed effectively to synchronously control multi-degrees of freedom HMI and for general multi-joint kinematics estimation purposes.     

Resistivity surveys near a waste-disposal site in the Qasr Tuba area of central Jordan

Direct current (DC) Schlumberger resistivity sounding and dipole-dipole resistivity profiling experiments were conducted at the border of an 2.2 long×1 km wide open waste disposal site in central Jordan. The site is on an approximately 20 m thick limestone, chert and chalk rock sequence and is surrounded by a series of hills. Lying upstream of an urban area, agricultural land and numerous groundwater wells, any contamination spreading from the waste disposal site could have a serious effect on the people and the environment. In this study, the subsurface resistivity distribution was mapped and compared with the data obtained from boreholes and aerial photographs. DC resistivity methods were found to be a fast and inexpensive data collection tool. The results obtained will be of use for engineering preparations and the operation of the site, as well as for monitoring any future pollution.      

The role of desalination in bridging the water gap in Jordan

The water resources of Jordan have always been scarce. The demand for water in the country exceeds the available resources and the gap between the water supply and demand is continuously increasing. Furthermore, the quality of water resources has dramatically deteriorated in recent years, which prevented the utilization of some resources. To secure the economic sustainability of the country, it is important at this stage to consider non-conventional water resources, such as sea and brackish water desalination. This study examines the water resources of Jordan, projected water demand, and the gap between the demand and supply based on two scenarios. The possibility of closing this gap by water desalination was investigated. Both sea and brackish water desalination were considered. The analysis revealed that seawater desalination process is economically infeasible for domestic water uses at this stage. This is attributed to that Jordan is not an oil producing country and the location of sea shoreline in Aqaba is on the Red Sea, away from the consumption centers. However, seawater desalination may be a viable option for tourist and industrial enterprises that will be established as a result of the new Law of Aqaba Free Zone. The most convenient and realistic option for Jordan in the short term, is the desalination of brackish water by reverse osmosis (RO). The brackish water with total dissolved solids between 2000-10000 mg/l is available from many aquifers and springs of the country. The study concluded that Jordan is facing a severe water crisis. Until recently, the water planners have not given the water desalination the required attention as a potential source of water supply. Taking into account the progress that is being achieved in the field of desalination technology, Jordan has to consider the desalination option more seriously and to start building a national capacity in the field of water desalination. It was emphasized that desalination is not a substitute to traditional water resources, it is rather a supplementary source that can contribute in bridging the water gap of the country.