Dual bus MAN's with multiple-priority traffic

A protocol with strictly preemptive priorities that does not admit low-priority traffic if the load from high-priority traffic exceeds the capacity of the transmission channel in a MAN is presented. The protocol guarantees fairness for transmissions at the highest priority level. By introducing a general characterization of bandwidth allocation schemes for dual bus networks, existing priority mechanisms can be categorized according to the provided quality of service. The unique existence of a bandwidth allocation scheme for multiple priority traffic is shown with a full utilization of the channel capacity, with a fair distribution of bandwidth respective to traffic from a particular priority level, and with preemptive priorities. The performance of the presented protocol is compared to existing proposals for multiple priority mechanisms. It is shown that adopting the new protocol results in shorter access delays for high-priority transmissions. The protocol allows the stations of the network to react quickly to load changes. It is shown that the effectiveness of the priority scheme, compared to priority schemes using the bandwidth-balancing mechanism, is less dependent on increasing the transmission speed of the network     

Structural and composition analysis of Apex™ and Foturan™ photodefinable glasses

Little is known about photostructurable glasses when compared to quartz and the other glass families. This article investigates optical and thermal behavior of the two commercially produced Apex? and Foturan? photosensitive glasses in relation to their composition. A composition analysis is performed on the two glasses using Rutherford backscattering spectrometry, and UV spectroscopy. Cerium and silver were found to exist at higher concentrations in Foturan than in Apex glass. Difference in transmission in the 240–340 nm window is mainly attributed to the different concentrations of cerium and silver in the glasses. Infrared transmission in the range of 2.7–5.0 μm is improved following an annealing process. Structural stability over a different range of temperatures in the two photosensitive glasses is investigated, and is attributed to the silica content at the expense of lithium oxide. Raman spectroscopy shows that the UV-exposed-then-baked photosensitive glass, results in the formation of a uniform crystalline-phase lithium metasilicate with a preponderantly Q₂ species.     

Hall current and gravity effect on magnetomicropolar thermoelastic medium with microtemperatures

This research is concerned with the effect of the gravity on micropolar thermoelastic medium possessing microtemperatures, using the modified Ohm's law taking into consideration the Hall current. The expressions for the physical quantities are obtained using the normal-mode analysis method. The comparisons established numerically and represented graphically in the presence and absence of the gravity, the Hall current effect and the micropolar property.     

Active radio frequency pulse compression using switched resonant delay lines

This paper presents a study and design methodology for enhancing the efficiency of the SLED II rf pulse-compression system [P.B. Wilson, Z.D. Farkas and R.D. Ruth, Linear Accel. Conf., Albuquerque, NM, 1990]. This system employs resonant delay lines as a means of storing rf energy. By making the external quality factor of these lines vary as a function of time, the intrinsic efficiency of the system can reach 100%. However, we demonstrate a considerable increase in efficiency even if the change of the quality factor is limited to a single event in time. During this event, the quality factor of the lines changes from one value to another. The difference between these two values is minimized to simplify the realization of the quality factor switch. We present the system optimum parameters for this case. We also show the extension of this system to two events in time, during which the quality factor of the line changes between three predetermined states. The effects of the losses due to the delay lines and the switch used to change the quality factor are also studied.     

Extreme scale computing: Modeling the impact of system noise in multi-core clustered systems

System noise or Jitter is the activity of hardware, firmware, operating system, runtime system, and management software events. It is shown to disproportionately impact application performance in current generation large-scale clustered systems running general-purpose operating systems (GPOS). Jitter mitigation techniques such as co-scheduling jitter events across operating systems improve application performance but their effectiveness on future petascale systems is unknown. To understand if existing jitter mitigation solutions enable scalable petascale performance, we construct two complementary jitter models based on detailed analysis of system noise from the nodes of a large-scale system running a GPOS. We validate these two models using experimental data from a system consisting of 256 GPOS instances with 8192 CPUs. Based on our models, we project a minimum slowdown of 1.8%, 4.1%, and 6.5% for applications executing on a similar one petaflop system running 1024 GPOS instances and having global synchronization operations once every 100 ms, 10 ms, and 1 ms, respectively. Our projections indicate that–although existing mitigation solutions enable scalable petascale performance–additional techniques are required to contain the impact of jitter on multi-petaflop systems, especially for tightly synchronized applications.     

Response of Semiconductor Medium of Variable Thermal Conductivity Due to Laser Pulses with Two-Temperature through Photothermal Process

Silicon - A novel model of variable thermal conductivity of semiconductor medium in two-temperature theory is studied. The Photothermal excitation due to laser pulses is investigated. The governing...     

Fiducial feature reduction analysis for electrocardiogram (ECG) based biometric recognition

Although the electrocardiogram (ECG) has been a reliable diagnostic tool for decades, its deployment in the context of biometrics is relatively recent. Its robustness to falsification, the evidence it carries about aliveness and its rich feature space has rendered the deployment of ECG based biometrics an interesting prospect. The rich feature space contains fiducial based information such as characteristic peaks which reflect the underlying physiological properties of the heart. The principal goal of this study is to quantitatively evaluate the information content of the fiducial based feature set in terms of their effect on subject and heart beat classification accuracy (ECG data acquired from the PhysioNet ECG repository). To this end, a comprehensive set of fiducial based features was extracted from a collection of ECG records. This feature set was subsequently reduced using a variety of feature extraction/selection methods such as principle component analysis (PCA), linear discriminant analysis (LDA), information-gain ratio (IGR), and rough sets (in conjunction with the PASH algorithm). The performance of the reduced feature set was examined and the results evaluated with respect to the full feature set in terms of the overall classification accuracy and false (acceptance/rejection) ratios (FAR/FRR). The results of this study indicate that the PASH algorithm, deployed within the context of rough sets, reduced the dimensionality of the feature space maximally, while maintaining maximal classification accuracy.     

Isozyme polymorphism of esterases in the genus Lanistes (Mollusca:Prosobranchiata) and genetic analysis of populations

Esterases from the digestive gland of the snails Lanistes carinatus and Lanistes bolteni collected from Egyptian governorates were extracted and analyzed using starch gel electrophoresis and five substrates. Twelve esterase bands were detected in both Lanistes species. The esterase bands were distributed in three main zones, which could be classified as acetylesterases, carboxylesterases, and cholinesterases. Depending on the substrates specificity, inhibition properties, and relative mobility of esterase bands, the three zones of esterase activity could be traced to eight genetic loci. Locality-specific loci were found. Inter- and intrapopulation variations are discussed. There is an absence of equilibria at all esterase loci in all populations studied, and a high proportion of genetic diversity in different esterase loci. The absence of interspecific variations proves that Lanistes snails in Egypt belong to one species.     

A programmable architecture for the provision of hybrid services

The success of new service provision platforms will largely depend on their ability to blend with existing technologies. The advent of Internet telephony, although impressive, is unlikely to make telephone customers suddenly turn in favor of computers. Rather, customers display increasing interest in services that span multiple networks (especially Internet protocol-based networks and the telephone and cellular networks) and open new vistas. We refer to these services as hybrid services and propose an architecture for their provision. This architecture allows for programming the service platform elements (i.e., network nodes, gateways, control servers, and terminals) in order to include new service logics. We identify components that can be assembled to build these logics by considering a service as a composition of features such as address translation, security, call control, connectivity, charging, and user interaction. Generic service components are derived from the modeling of these features. We assure that our proposal can be implemented even in existing systems in return for slight changes. These systems are required to generate an event when a special service is encountered. The treatment of this event is handled by an object at a Java service layer. Java has been chosen for its platform-neutrality property and its embedded security mechanisms. Using our architecture, we design a hybrid closed user group service