Miracle-dz/UniFAR-FTUs huggingface dataset:
Average Channel Utilization of CSMA With Geometric Distribution Under Varying Workload

Performance analysis of fixed-size contention window carrier sense multiple-access (CSMA) protocol with geometric distribution for slot selection probability is addressed in the paper. This MAC scheme, called Sift, was initially proposed for large-scale event-driven wireless sensor networks. The goal of the present paper is to evaluate the standard performance measures (throughput, protocol capacity, collision rate, and mean access delay) for geometrically distributed CSMA both in the context of data-centric dense sensor networks and node-centric industrial automation systems. The analytical approach based on the stochastic analysis has been applied. To demonstrate how the protocol is able to cope with bursty traffic, the average throughput defined over a specified workload range has been introduced and examined. Using the average throughput as the performance criterion, the geometric CSMA has been compared to conventional CSMA schemes with uniform distribution. The latter are represented by the classical p-persistent CSMA and the predictive p-persistent CSMA used in LonWorks control networks. It is shown that G-CSMA is overload-tolerant event-driven MAC protocol since the average throughput may be kept on high level in wide range of workload if the shape of geometric distribution is well chosen.
Human Information Retrieval

Information retrieval in the age of Internet search engines has become part of ordinary discourse and everyday practice: "Google" is a verb in common usage. Thus far, more attention has been given to practical understanding of information retrieval than to a full theoretical account. In Human Information Retrieval, Julian Warner offers a transformative overview of information retrieval, synthesizing theories from different disciplines (information and computer science, librarianship and indexing, and information society discourse) and incorporating such disparate systems as WorldCat and Google into a single, robust theoretical framework. There is a need for such a theoretical treatment, he argues, one that reveals the structure and underlying patterns of this complex field while remaining congruent with everyday practice. Warner presents a labor theoretic approach to information retrieval, building on his previously formulated distinction between semantic and syntactic mental labor, arguing that the description and search labor of information retrieval can be understood as both semantic and syntactic in character. Warner's information science approach is rooted in the humanities and the social sciences but informed by an understanding of information technology and information theory. The chapters offer a progressive exposition of the topic, with illustrative examples to explain the concepts presented. Neither narrowly practical nor largely speculative, Human Information Retrieval meets the contemporary need for a broader treatment of information and information systems. History and Foundations of Information Science series
Applying J 2 EE patterns to develop a SOA-based architecture for ecological niche modelling

The purpose of ecological niche modelling is to obtain a probabilistic species distribution based on species localization and environmental data. The problem is highly complex from the architectural viewpoint because its requirements include different distributed, interoperable and integration issues. Monolithic solutions were proposed and implemented but they were not able to achieve all requirements. Therefore, it is not unusual the researcher to need many different software packages to perform a complete ecological niche modelling process. A reference Service Oriented Architecture, SOA, was proposed to improve the previous monolithic solutions and enable many missing functionatilies, such as distributed processing and data exchange among different providers. The proposed architecture was organized into layers and, to implement the application correspondent to this architectural solution, the adoption of standards was required to enable distributed operations and to allow component reuse and the evolution of the ecological niche modelling technique with minimum development and integration efforts. The J2EE patterns were chosen to accomplish part of the implementation task because of its adequacy to the SOA architectural requirements, since essential facilities to implement this category of solutions are contempled by J2EE platform. This work describes the application of J2EE patterns in order to develop and implement a SOA-based architecture for solving the ecological niche modelling problem, offering a highly improved solution to the researchers of the biodiversity area, due to its distributed nature. Besides, as standards solutions were considered in all phases of the system project and development, this implementation does not present the same restritions of the other available software packages for ecological niche modelling, specially related to the integration viewpoint. In addition to solve the ecological niche modelling specific problem, this work shows the patterns application and the main steps required to develop and implement solutions to problems with similar requirements, thus it also may be used as a reference to solve problems in other
The use of deep learning features in a hierarchical classifier learned with the minimization of a non-greedy loss function that delays gratification

Recently, we have observed the traditional feature representations are being rapidly replaced by the deep learning representations, which produce significantly more accurate classification results when used together with the linear classifiers. However, it is widely known that non-linear classifiers can generally provide more accurate classification but at a higher computational cost involved in their training and testing procedures. In this paper, we propose a new efficient and accurate non-linear hierarchical classification method that uses the aforementioned deep learning representations. In essence, our classifier is based on a binary tree, where each node is represented by a linear classifier trained using a loss function that minimizes the classification error in a non-greedy way, in addition to postponing hard classification problems to further down the tree. In comparison with linear classifiers, our training process increases only marginally the training and testing time complexities, while showing competitive classification accuracy results. In addition, our method is shown to generalize better than shallow non-linear classifiers. Empirical validation shows that the proposed classifier produces more accurate classification results when compared to several linear and non-linear classifiers on Pascal VOC07 database.
A variable resource allocation access control algorithm for mobile converged networks

Aiming at the problems of high access rejection probability and low resource usage ratio of traditional access control algorithms for mobile converged networks, a distributed shared resource allocation model is proposed. The features of multiple access networks resource allocation and quality of service (QoS) level are also discussed. A variable resource allocation access control algorithm (VRAACA) is presented. In this algorithm, the resource is re-adjusted according to the require QoS level and system efficient. Experimental results demonstrate that the VRAACA is better than other traditional algorithms in access successful ratio, system resource utilization and system efficient, so the VRAACA is suitable for the application of access control in mobile converged networks.
Reducing Quantization Noise to Boost Efficiency and Signal Bandwidth in Delta–Sigma-Based Transmitters

This paper introduces two new techniques to enhance both efficiency and signal bandwidth in delta-sigma-based transmitters. At first step, a technique called quantization noise reduction (QNR), is introduced to enhance the coding efficiency. By filtering out part of the quantization noise in the whole band of the signal, while the signal envelope is maintained almost constant, the coding efficiency is improved without imposing any additional nonlinearity or distortion to the system. By utilizing this technique for an orthogonal frequency division multiplexing (OFDM) signal with 1.25-MHz bandwidth and 80 times oversampling, with 8.1-dB peak-to-average power ratio (PAPR), the coding efficiency is improved from 8.8% to 14.5% while the signal-to-noise distortion ratio (SNDR) of the system remains 43 dB. In the next step by using a controlled filtering on in-band quantization noise along with QNR technique, the bandwidth of the signal and efficiency are increased simultaneously without losing as much linearity. The second technique is called quantization noise reduction with in-band filtering or (QNRIF). QNRIF is applied on an OFDM signal with 1.25-MHz bandwidth, with the same PAPR and only 16 times oversampling. The result for the coding efficiency is improved from 7.7% to 18.7% with 41-dB SNDR.
Fabrication of nanocontacts for molecular devices using nanoimprint lithography

We present a simple process to fabricate gold nanocontacts with a gap as small as sub-10 nm. This method uses a two-step process of nanoimprint lithography (NIL) and electromigration. First, 20 nm wide gold nanowires were fabricated by NIL on a silicon dioxide substrate. Then by passing an electric current through a nanowire, the nanowire is split into two wires with a gap as small as sub-10 nm by electromigration. This fabrication method offers a fast and effective process for producing large numbers of nanocontacts for use in molecular self-assembly, and thus greatly enhances the probability of successful capture of single molecules.
Genomic and Biochemical Analysis of the Diaminopimelate and Lysine Biosynthesis Pathway in Verrucomicrobium spinosum: Identification and Partial Characterization of L,L-Diaminopimelate Aminotransferase and UDP-N-Acetylmuramoylalanyl-D-glutamyl-2,6-meso-Diaminopimelate Ligase

The Gram-negative bacterium Verrucomicrobium spinosum has attracted interest in recent years following the sequencing and annotation of its genome. Comparative genomic analysis of V. spinosum using diaminopimelate/lysine metabolic genes from Chlamydia trachomatis suggests that V. spinosum employs the L,L-diaminopimelate aminotransferase (DapL) pathway for diaminopimelate/lysine biosynthesis. The open reading frame corresponding to the putative dapL ortholog was cloned and the recombinant enzyme was shown to possess L,L-diaminopimelate aminotransferase activity in vitro. In vivo analysis using functional complementation confirmed that the dapL ortholog was able to functionally complement an E. coli mutant that confers auxotrophy for diaminopimelate and lysine. In addition to its role in lysine biosynthesis, the intermediate diaminopimelate has an integral role in peptidoglycan biosynthesis. To this end, the UDP-N-acetylmuramoylalanyl-d-glutamyl-2,6-meso-diaminopimelate ligase ortholog was also identified, cloned, and was shown to possess meso-diaminopimelate ligase activity in vivo. The L,L-diaminopimelate aminotransferase pathway has been experimentally confirmed in several bacteria, some of which are deemed pathogenic to animals. Since animals, and particularly humans, lack the genetic machinery for the synthesis of diaminopimelate/lysine de novo, the enzymes involved in this pathway are attractive targets for development of antibiotics. Whether dapL is an essential gene in any bacteria is currently not known. V. spinosum is an excellent candidate to investigate the essentiality of dapL, since the bacterium employs the DapL pathway for lysine and cell wall biosynthesis, is non-pathogenic to humans, facile to grow, and can be genetically manipulated.
Resolving a zoological mystery: the kouprey is a real species

The kouprey is a rare and enigmatic forest ox discovered by scientists in Cambodia only in 1937. Numerous morphological hypotheses have been proposed for the origin of the kouprey: that it is a species closely related to banteng and gaur, two other wild oxen of southeast Asia; a morphologically divergent species placed in a separate genus, named Novibos; a wild species linked to aurochs and domestic cattle; a vicariant population of banteng; a feral cattle; or a hybrid of banteng with either zebu cattle, gaur or water buffalo. In a recent paper, which gained a lot of media coverage, Galbreath et al. analysed mitochondrial DNA sequences and concluded that the kouprey never existed as a wild, natural species, and that it was a feral hybrid between banteng and zebu cattle. Here we analyse eight DNA markers—three mitochondrial regions and five nuclear fragments—representing an alignment of 4582 nucleotides for the holotype of the kouprey and all related species. Our results demonstrate that the kouprey is a real and naturally occurring species, and show that Cambodian populations of banteng acquired a mitochondrial genome of kouprey by natural introgressive hybridization during the Pleistocene epoch.
A hypergraph-based storage policy for RDF version management system

Versioning schemes for RDF data can play an important role in the management of Semantic web based information. The storage space and the version retrieval is one of the most significant aspects in version management. However, the existing methods have limitations in that they are not efficient in constructing the version. Therefore, there is a need for new and improved techniques that achieve better performance. In this paper, we proposed a hypergraph-based storage policy for RDF version management, which exploits hyperedges and vertices to maintain the information of version. This scheme enables us to reduce the space overhead and reconstruct a specific version efficiently. In addition, we proposed an optimization technique, which results in considerable space saving. An experimental study with RDF data sets shows the proposed storage policy achieved reduced storage space and efficiently reconstructed the version.
New Developments in String Gravity and String Cosmology.A Summary Report

New Developments in String Gravity and String Cosmology are reported: 1-String driven cosmology and its Predictions. 2-The primordial gravitational wave background in string cosmology. 3-Non-singular string cosmologies from Exact Conformal Field Theories. 4-Quantum Field Theory, String Temperature and the String Phase of de Sitter space-time, 5-Hawking Radiation in String Theory and the String Phase of Black Holes. 6-New Dual Relation between Quantum Field Theory regimes and String regimes in Curved Backgrounds, and the 'QFT/String Tango'. 7- New Coherent String States and Minimal Uncertainty Principle in WZWN models
Framework for Providing Security and Energy saving Using Elliptic Curve Cryptography in Wireless Sensor Networks

In this recent years wireless sensors attracted the wireless sensor networks due to the significant advances in minimization. Wireless sensor networks consist of autonomous sensor nodes attached to one or more base stations. Wireless networks of low-power sensing devices are poised to become a ubiquitous part of the computing landscape. As Wireless sensor networks continues to grow, they become vulnerable to attacks and hence the need for effective security mechanisms. Due to these well accepted limitations, WSN is not able to deal with traditional cryptographic algorithms and symmetric based cryptographic schemes don’t scale well when the number of sensor nodes increases. Sensor nodes should be resilient to attacks. Since WSN suffer from many constraints including low battery life, lower processing power, small memory and wireless communication channel. In this paper we propose an energy efficient secure framework that proves the integrity, authentication, and also provides secure communication among the sensor nodes by using the public key algorithm.
Weak consistency as a last resort

It is well-known that using a replicated service requires a tradeoff between availability and consistency. Eventual Linearizability represents a midpoint in the design spectrum, since it can be implemented ensuring availability in worst-case periods and providing strong consistency in the regular case. In this paper we show how Eventual Linearizability can be used to support master-worker schemes such as workload sharding in Web applications. We focus on a scenario where sharding maps the workload to a pool of servers spread over an unreliable wide-area network. In this context, Linearizability is desirable, but it may prevent achieving sufficient availability and performance. We show that Eventual Linearizability can significantly reduce the time to completion of the workload in some settings.
Thermalization in Relativistic Outflows and the Correlation between Spectral Hardness and Apparent Luminosity in Gamma-Ray Bursts

We present an interpretation of the phenomenological relations between the spectral peak, isotropic luminosity, and duration of long gamma-ray bursts that have been discovered by Amati and coworkers, Ghirlanda and coworkers, Firmani and coworkers, and Liang & Zhang. In our proposed model, a jet undergoes internal dissipation which prevents its bulk Lorentz factor from exceeding 1/θ (θ being the jet opening angle) until it escapes from the core of its progenitor star, at a radius of order 1010 cm; dissipation may continue at larger radii. The dissipated radiation will be partially thermalized, and we identify its thermal peak (Doppler boosted by the outflow) with Epk. The radiation comes, in effect, from within the jet photosphere. The nonthermal, high-energy part of the GRB emission arises from Comptonization of this radiation by relativistic electrons and positrons outside the effective photosphere. This model can account naturally not only for the surprisingly small scatter in the various claimed correlations, but also for the normalization, as well as the slopes. It then has further implications for the jet energy, the limiting jet Lorentz factor, and the relation of the energy, opening angle and burst duration to the mass and radius of the stellar stellar progenitor. The observed relation between pulse width and photon frequency can be reproduced by inverse Compton emission at ~1014 cm from the engine, but there are significant constraints on the energy distribution and isotropy of the radiating particles.
How Attention Affects Spatial Resolution Attention Is a Selective Process

We summarize and discuss a series of psychophysical studies on the effects of spatial covert attention on spatial resolution, our ability to discriminate fine patterns. Heightened resolution is beneficial in most, but not all, visual tasks. We show how endogenous attention (voluntary, goal driven) and exogenous attention (involuntary, stimulus driven) affect performance on a variety of tasks mediated by spatial resolution, such as visual search, crowding, acuity, and texture segmentation. Exogenous attention is an automatic mechanism that increases resolution regardless of whether it helps or hinders performance. In contrast, endogenous attention flexibly adjusts resolution to optimize performance according to task demands. We illustrate how psychophysical studies can reveal the underlying mechanisms of these effects and allow us to draw linking hypotheses with known neurophysiological effects of attention. Each time we open our eyes we are confronted with an overwhelming amount of information. Yet, we seemingly understand our visual world effortlessly. To make sense of a scene, we need to detect, localize, and identify relevant information. By focusing on a certain location or aspect of the visual scene, attention allows us to selectively process information, prioritizing some aspects of information while ignoring others. Attention lies at the crossroads between perception and cognition, bringing together scientists using psychophysics, neurophysiolo-gy, neuroimaging, and computational neuroscience techniques. Significant advances in visual attention have been facilitated by fruitful cross talk among these fields and levels of analyses. The interest in visual attention has exponentially grown; a PubMed search yields more than 3500 articles dealing with visual attention since 1970 (" visual attention " in title or abstract), with half of them published since 2008 (Fig. 1). Changes in an ob-server's attentional state while keeping the retinal image constant can affect perceptual performance and appearance , as well as the activity of " sensory " neurons throughout visual cortex. Selective attention arises from the brain's limited capacity to process information. The fixed amount of overall energy available to the brain and the high bioenergetic cost of the neuronal activity involved in cortical computation require the use of efficient representational codes that rely on a sparse collection of active neurons, as well as the flexible allocation of metabolic resources according to task demands. These energy limitations allow only a small fraction of the machinery to be engaged concurrently , and provide a neurophysiological basis for selective attention (Lennie 2003; Carrasco 2011). The notion that stimuli compete for limited …
Concurrency Control for Real Time Groupware

Groupware systems use computers and networks to facilitate collaborative working. With reference to shared data objects they may be contrasted with, for example, distributed databases where the emphasis is on protecting and hiding the actions of concurrent users from each other. Groupware versions of applications such as document editors and spreadsheets must support a model where there are multiple concurrent readers and writers whose actions are visible to each other. Furthermore, if the groupware application is intended for interactive use then its responsiveness becomes an important feature and this also impacts on the selection of a concurrency control policy for the system. * This work is supported by JISC/NTI 229, "Distributed SuperComputing: High Speed Scalable Networking", alias WARP.
Estimating the Empirical Cost Function of Routines with Dynamic Workloads

A crucial aspect in software development is understanding how an application's performance scales as a function of its input data. Estimating the empirical cost function of individual routines of a program can help developers predict the runtime on larger workloads and pinpoint asymptotic inefficiencies in the code. While this has been the target of extensive research in performance profiling, a major limitation of state-of-the-art approaches is that the input size is assumed to be determinable from the program's state prior to the invocation of the routine to be profiled, failing to characterize the scenario where routines dynamically receive input values during their activations. This results in missing workloads generated by kernel system calls (e.g., in response to I/O or network operations) or by other threads, which play a crucial role in modern concurrent and interactive applications. Measuring dynamic workloads poses several challenges, requiring shared-memory communication between threads to be efficiently traced. In this paper we present a new metric and an efficient algorithm for automatically estimating the size of the input of each routine activation. We provide examples showing that our metric allows the estimation of the empirical cost functions of complex applications more precisely than previous approaches. An extensive experimental investigation on a variety of benchmarks shows that our metric can be integrated in a Valgrind-based profiler incurring overheads comparable to other prominent heavyweight dynamic analysis tools.