bluuebunny/crossref_metadata_2025_split huggingface dataset:
Analysis of cooperative MIMO transmission system with transmit antenna selection and selection combining
Authors: Karaevli İzzet Levent , Kurt Güneş Karabulut , Altunbaş İbrahim 
Published: November 2010

ABSTRACTError performance of a cooperative system can be enhanced by using transmit and receive diversity techniques at transmission links. The number of transmit/receive RF chain pairs required to achieve full diversity can be decreased to one for each link by using transmit antenna selection (TAS) method at the transmitter and selection combining (SC) method at the receiver. Thus, hardware complexity of a multiple input multiple output (MIMO) cooperative scheme can be significantly reduced when compared to systems that use TAS and maximum ratio combining (MRC). In this paper, we investigate the performance of an amplify‐and‐forward cooperative system where TAS/SC is utilized. We derive the probability density function (pdf) of end‐to‐end SNR of the system for Rayleigh fading channels. By using this pdf, we obtain the exact symbol error rate expressions for M‐PSK and M‐QAM modulations and the exact outage probability expression. We also obtain the asymptotical diversity order using upper and lower bounds of the outage probability expression and show that our system provides the same diversity order as the cooperative system where TAS/MRC is utilized. We verify our results via computer simulations. Copyright © 2010 John Wiley & Sons, Ltd.
DBM-Tree: Trading height-balancing for performance in metric access methods
Authors: Vieira Marcos R. , Traina Caetano , Chino Fabio J. T. , Traina Agma J. M. 
Published: November 2010

Abstract
Metric Access Methods (MAM) are employed to accelerate the processing of similarity queries, such as the range and the k-nearest neighbor queries. Current methods, such as the Slim-tree and the M-tree, improve the query performance minimizing the number of disk accesses, keeping a constant height of the structures stored on disks (height-balanced trees). However, the overlapping between their nodes has a very high influence on their performance. This paper presents a new dynamic MAM called theDBM-tree (Density-Based Metric tree), which can minimize the overlap between high-density nodes by relaxing the height-balancing of the structure. Thus, the height of the tree is larger in denser regions, in order to keep a tradeoff between breadth-searching and depth-searching. An underpinning for cost estimation on tree structures is their height, so we show a non-height dependable cost model that can be applied for DBM-tree. Moreover, an optimization algorithm calledShrink is also presented, which improves the performance of an already builtDBM-tree by reorganizing the elements among their nodes. Experiments performed over both synthetic and real world datasets showed that theDBM-tree is, in average, 50% faster than traditional MAM and reduces the number of distance calculations by up to 72% and disk accesses by up to 66%. After performing the Shrink algorithm, the performance improves up to 40% regarding the number of disk accesses for range andk-nearest neighbor queries. In addition, theDBM-tree scales up well, exhibiting linear performance with growing number of elements in the database.
The weighted gradient: A color image gradient applied to morphological segmentation
Authors: Flores Franklin César , Polidório Airton Marco , Lotufo Roberto de Alencar 
Published: November 2010

AbstractThis paper proposes a method for color gradient computation applied to morphological segmentation of color images. The weighted gradient (with weights estimated automatically), proposed in this paper, applied in conjunction with the watershed from markers technique, provides excelent segmentation results, according to a subjective visual criterion. The weighted gradient is computed by linear combination of the gradients from each band of an image under the IHS color space model. The weights to each gradient are estimated by a systematic method that computes the similarity between the image to compute the gradient and an ”ideal image”, whose histogram has an uniform distribution. Several experiments were done in order to compare the segmentation results provided by the weighted gradient to the results provided by other color space metrics, also according to a subjective criterion, and such comparison is present in this paper.
Frequency domain concurrent channel equalization for multicarrier systems
Authors: D’Agostini Fábio , Júnior Sirlesio Carboni , De Castro Maria C. F. , De Castro Fernando C. C. 
Published: November 2010

AbstractReceivers for wireless Orthogonal Frequency Division Multiplexing (OFDM) systems usually perform the channel estimation based on pilot carriers in known positions of the channel spectrum. Interpolation between pilot carriers is applied to determine the channel transfer function in all carrier frequencies. Channel variations along time are compensated by means of interpolation between successive channel estimates on the same carrier frequency. However, not rarely, the fast channel variations exceed the time interpolator capability, as is the case for mobile operation. In this article we present a new channel compensation technique based on the concurrent operation of two stochastic gradient timedomain algorithms, one which minimizes a cost function that measures the received signal energy dispersion and other which minimizes the Euclidean distance between the received digital modulation symbols and the ones in the reference constellation assigned to each OFDM sub-channel. Results show that the new technique advantageously improves the system robustness to fast channel variations since, with a low computational cost, it dramatically reduces the demodulator symbol error rate even when the receiver is operating in an intense dynamic multipath scenario.
Ginga-NCL: the declarative environment of the Brazilian digital TV System
Authors: Soares Luiz Fernando Gomes , Rodrigues Rogério Ferreira , Moreno Márcio Ferreira 
Published: November 2010

Abstract
As in all main terrestrial DTV Systems, the Brazilian middleware, named Ginga, supports both declarative applications (through its presentation, or declarative, environment Ginga-NCL) and procedural applications (through its execution, or procedural, environment Ginga-J). Since hybrid applications are common, either type of Ginga application may make use of facilities of both presentation and execution application environments. This paper focuses on the presentation environment Ginga-NCL. The main Brazilian inovations are then presented, regarding the Ginga architecture, the declarative NCL language specification, the editing commands for live application production, and the transport data structure.
An integrated role-based approach for modeling, designing and implementing multi-agent systems
Authors: Zhang Xiaoqin , Xu Haiping , Shrestha Bhavesh 
Published: November 2010

AbstractTo facilitate the development of multi-agent systems and improve the reusability, robustness and feasibility of these systems, we have developed a role-based agent development framework (RADE). In this paper, we present an integrated approach for modeling, designing and implementing multi-agent systems using RADE. We describe the design of agents and motivations within such framework. We introduce a practical approach for modeling agent’s motivation and specifying agent’s goals, where a role-agent mapping mechanism is developed based on this design. Dynamic task allocation is achieved through the creation of role instances and the mapping from role instances to agents. We also introduce the RTÆMS language based on the extension of TÆMS to model the plan tree for each goal. This representation enables the reuse of general planning/scheduling and collaboration/cooperation mechanisms developed in multi-agent system research community. We have developed an automatic agent generation interface and also implemented a simple demo system in health care domain.
Automated formal specification generation and refinement from requirement documents
Authors: Cabral Gustavo , Sampaio Augusto 
Published: November 2010

AbstractThe automatic generation of formal specifications from requirements suppresses the complexity of formal models manual creation and reveals the immediate benefits of its usage, such as the possibility to carry out refinements, and property verification, which contributes to project cost reduction and quality improvement. This paper proposes a Controlled Natural Language (CNL), a subset of English, used to write use case specifications according to a template. From these use cases a complete strategy and tools enable the generation of process algebraic formal models in the CSP notation. We define templates that represent requirements at different levels of abstraction, capturing different views of the system behavior. Moreover, a refinement notion is defined to connect the generated CSP models through an event mapping relation between abstract and concrete models. This notion is further applied to detail use case specifications and to automate its execution.
Helly property, clique raphs, complementary graph classes, and sandwich problems
Authors: Dourado Mitre C. , Petito Priscila , Teixeira Rafael B. , de Figueiredo Celina M. H. 
Published: November 2010

Abstract
A sandwich problem for property π asks whether there exists a sandwich graph of a given pair of graphs which has the desired property π Graph sandwich problems were first defined in the context of Computational Biology as natural generalizations of recognition problems. We contribute to the study of the complexity of graph sandwich problems by considering the Helly property and complementary graph classes. We obtain a graph class defined by a finite family of minimal forbidden subgraphs for which the sandwich problem is NP-complete. A graph is clique-Helly when its family of cliques satisfies the Helly property. A graph is hereditary clique-Helly when all of its induced subgraphs are clique-Helly. The clique graph of a graph is the intersection graph of the family of its cliques. The recognition problem for the class of clique graphs was a long-standing open problem that was recently solved. We show that the sandwich problems for the graph classes: clique, clique-Helly, hereditary clique-Helly, and clique-Helly nonhereditary are all NP-complete. We propose the study of the complexity of sandwich problems for complementary graph classes as a mean to further understand the sandwich problem as a generalization of the recognition problem.
CinBalada: A multiagent rhythm factory
Authors: Sampaio Pablo Azevedo , Ramalho Geber , Tedesco Patrícia 
Published: November 2010

AbstracCinBalada is a system for automatic creation of polyphonic rhythmic performances by mixing elements from different musical styles. This system is based on agents that act as musicians playing percussion instruments in a drum circle. Each agent has to choose from a database the rhythm pattern of its instrument that satisfies the “rhythmic role” assigned to him in order to produce a collectivelyconsistent rhythmic performance. A rhythmic role is a concept that we proposed here with the objective of representing culture-specific rules for creation of polyphonic performances.
A hybrid heuristic for the multi-plant capacitated lot sizing problem with setup carry-over
Authors: Nascimento Mariá C. V. , Toledo Franklina M. B. 
Published: November 2010

Abstract
This paper addresses the capacitated lot sizing problem (CLSP) with a single stage composed of multiple plants, items and periods with setup carry-over among the periods. The CLSP is well studied and many heuristics have been proposed to solve it. Nevertheless, few researches explored the multi-plant capacitated lot sizing problem (MPCLSP), which means that few solution methods were proposed to solve it. Furthermore, to our knowledge, no study of the MPCLSP with setup carry-over was found in the literature. This paper presents a mathematical model and a GRASP (Greedy Randomized Adaptive Search Procedure) with path relinking to the MPCLSP with setup carry-over. This solution method is an extension and adaptation of a previously adopted methodology without the setup carry-over. Computational tests showed that the improvement of the setup carry-over is significant in terms of the solution value with a low increase in computational time.
Ontology matching for dynamic publication in semantic portals
Authors: Lachtim Fernanda Aparecida , de Carvalho Moura Ana Maria , Cavalcanti Maria Cláudia 
Published: November 2010

Abstract
Semantic portals are characterized for storing and structuring content according to specific domain ontologies. This content is represented through ontological languages, which enable not only adding semantic value to information treatment, but also inferring new knowledge from it. Publication in a semantic portal is typically done by instantiating its ontology, and this is often performed manually or through the use of specific forms. However, in order to keep portals constantly up-to-date, it is necessary to provide means for a more dynamic publication, integrating the portal content with information retrieved from different ontology-based sites on the same or on complementary domains. Reusing information from different ontologies requires specific and efficient mechanisms to align them, taking into account syntactical and semantical conflicts. This paper proposes an extension of the Crosi Mapping System, a matching mechanism which calculates similarities between ontologies. Some of its original algorithms have been enriched with additional functionality. This extension, namede-CMS, has been evaluated using the OAEI ontology alignment benchmark, and results show an increase of 69% in alignment precision when compared to the CMS original version. In order to illustrate its use, thee-CMS strategy was applied to SiGePoS, a System for Generating Semantic Portals. The semantic module, one of the system components, implements the alignment mechanism between ontologies, which is performed by thee-CMS.
A practical approach to cystic lung disease on HRCT
Authors: Beddy Peter , Babar Judith , Devaraj Anand 
Published: November 2010

Abstract
A lung cyst is defined as a round parenchymal lucency or area of low attenuation with a thin wall. They are not uncommon findings on high-resolution (HR) thoracic computed tomography (CT) and when identified, they require explanation. The differential diagnosis for diseases characterised by lung cysts is broad ranging from isolated chest disorders to rare multisystem diseases. This article provides a practical approach for evaluating lung cysts on HRCT, highlighting disorders in which the HRCT findings can be diagnostic as well as conditions where correlation with clinical history or biopsy is required.
PEACE AGREEMENTS OR PIECES OF PAPER? THE IMPACT OF UNSC RESOLUTION 1325 ON PEACE PROCESSES AND THEIR AGREEMENTS
Authors: Bell Christine , O'Rourke Catherine 
Published: November 2010

AbstractOn the 31 October 2000 UNSC Resolution 1325 was adopted. The resolution provided for a range of measures aimed at the inclusion of women in the prevention, management and resolution of conflict. In particular, several of the resolution's provisions addressed the role of women and gender in peace negotiations and agreements. This article examines whether and how Resolution 1325 has impacted on the drafting of peace agreements. We analyse explicit references to women and gender in peace agreements from 1990 to 2010, providing a quantitative and qualitative assessment of the extent to which women and gender are addressed. We conclude by using our findings and analysis to address the relationship of feminist intervention to international law, and debates around the strategies and trade-offs which underlie feminist promotion and use of UN Security Council Resolutions in particular.
Microbial methanol uptake in northeast Atlantic waters
Authors: Dixon Joanna L , Beale Rachael , Nightingale Philip D 
Published: November 2010

Abstract
Methanol is the predominant oxygenated volatile organic compound in the troposphere, where it can significantly influence the oxidising capacity of the atmosphere. However, we do not understand which processes control oceanic concentrations, and hence, whether the oceans are a source or a sink to the atmosphere. We report the first methanol loss rates in seawater by demonstrating that 14C-labelled methanol can be used to determine microbial uptake into particulate biomass, and oxidation to 14CO2. We have found that methanol is used predominantly as a microbial energy source, but also demonstrated its use as a carbon source. We report biological methanol oxidation rates between 2.1 and 8.4 nmol l−1 day−1 in surface seawater of the northeast Atlantic. Kinetic experiments predict a Vmax of up to 29 nmol l−1 day−1, with a high affinity Km constant of 9.3 nm in more productive coastal waters. We report surface concentrations of methanol in the western English channel of 97±8 nm (n=4) between May and June 2010, and for the wider temperate North Atlantic waters of 70±13 nm (n=6). The biological turnover time of methanol has been estimated between 7 and 33 days, although kinetic experiments suggest a 7-day turnover in more productive shelf waters. Methanol uptake rates into microbial particles significantly correlated with bacterial and phytoplankton parameters, suggesting that it could be used as a carbon source by some bacteria and possibly some mixotrophic eukaryotes. Our results provide the first methanol loss rates from seawater, which will improve the understanding of the global methanol budget.
Tuning the reactivity of semiconductor surfaces by functionalization with amines of different basicity
Authors: Bent Stacey F. , Kachian Jessica S. , Rodríguez-Reyes Juan Carlos F. , Teplyakov Andrew V. 
Published: November 2010

Surface functionalization of semiconductors has been the backbone of the newest developments in microelectronics, energy conversion, sensing device design, and many other fields of science and technology. Over a decade ago, the notion of viewing the surface itself as a chemical reagent in surface reactions was introduced, and adding a variety of new functionalities to the semiconductor surface has become a target of research for many groups. The electronic effects on the substrate have been considered as an important consequence of chemical modification. In this work, we shift the focus to the electronic properties of the functional groups attached to the surface and their role on subsequent reactivity. We investigate surface functionalization of clean Si(100)-2 × 1 and Ge(100)-2 × 1 surfaces with amines as a way to modify their reactivity and to fine tune this reactivity by considering the basicity of the attached functionality. The reactivity of silicon and germanium surfaces modified with ethylamine (CH
3
CH
2
NH
2
) and aniline (C
6
H
5
NH
2
) is predicted using density functional theory calculations of proton attachment to the nitrogen of the adsorbed amine to differ with respect to a nucleophilic attack of the surface species. These predictions are then tested using a model metalorganic reagent, tetrakis(dimethylamido)titanium (((CH
3
)
2
N)
4
Ti, TDMAT), which undergoes a transamination reaction with sufficiently nucleophilic amines, and the reactivity tests confirm trends consistent with predicted basicities. The identity of the underlying semiconductor surface has a profound effect on the outcome of this reaction, and results comparing silicon and germanium are discussed.
The necessity of adjusting tests of protein category enrichment in discovery proteomics
Authors: Louie Brenton , Higdon Roger , Kolker Eugene 
Published: November 2010

Abstract
Motivation: Enrichment tests are used in high-throughput experimentation to measure the association between gene or protein expression and membership in groups or pathways. The Fisher's exact test is commonly used. We specifically examined the associations produced by the Fisher test between protein identification by mass spectrometry discovery proteomics, and their Gene Ontology (GO) term assignments in a large yeast dataset. We found that direct application of the Fisher test is misleading in proteomics due to the bias in mass spectrometry to preferentially identify proteins based on their biochemical properties. False inference about associations can be made if this bias is not corrected. Our method adjusts Fisher tests for these biases and produces associations more directly attributable to protein expression rather than experimental bias.
Results: Using logistic regression, we modeled the association between protein identification and GO term assignments while adjusting for identification bias in mass spectrometry. The model accounts for five biochemical properties of peptides: (i) hydrophobicity, (ii) molecular weight, (iii) transfer energy, (iv) beta turn frequency and (v) isoelectric point. The model was fit on 181 060 peptides from 2678 proteins identified in 24 yeast proteomics datasets with a 1% false discovery rate. In analyzing the association between protein identification and their GO term assignments, we found that 25% (134 out of 544) of Fisher tests that showed significant association (q-value ≤0.05) were non-significant after adjustment using our model. Simulations generating yeast protein sets enriched for identification propensity show that unadjusted enrichment tests were biased while our approach worked well.
Contact: eugene.kolker@seattlechildrens.org
Supplementary information: Supplementary data are available at Bioinformatics online.
Maturation Stress Generation in Poplar Tension Wood Studied by Synchrotron Radiation Microdiffraction
Authors: Clair Bruno , Alméras Tancrède , Pilate Gilles , Jullien Delphine , Sugiyama Junji , Riekel Christian 
Published: November 2010

Abstract
Tension wood is widespread in the organs of woody plants. During its formation, it generates a large tensile mechanical stress called maturation stress. Maturation stress performs essential biomechanical functions such as optimizing the mechanical resistance of the stem, performing adaptive movements, and ensuring the long-term stability of growing plants. Although various hypotheses have recently been proposed, the mechanism generating maturation stress is not yet fully understood. In order to discriminate between these hypotheses, we investigated structural changes in cellulose microfibrils along sequences of xylem cell differentiation in tension and normal wood of poplar (Populus deltoides × Populus trichocarpa ‘I45-51’). Synchrotron radiation microdiffraction was used to measure the evolution of the angle and lattice spacing of crystalline cellulose associated with the deposition of successive cell wall layers. Profiles of normal and tension wood were very similar in early development stages corresponding to the formation of the S1 layer and the outer part of the S2 layer. Subsequent layers were found with a lower microfibril angle (MFA), corresponding to the inner part of the S2 layer of normal wood (MFA approximately 10°) and the G layer of tension wood (MFA approximately 0°). In tension wood only, this steep decrease in MFA occurred together with an increase in cellulose lattice spacing. The relative increase in lattice spacing was found close to the usual value of maturation strains. Analysis showed that this increase in lattice spacing is at least partly due to mechanical stress induced in cellulose microfibrils soon after their deposition, suggesting that the G layer directly generates and supports the tensile maturation stress in poplar tension wood.