bluuebunny/crossref_metadata_2025 huggingface dataset:
Provenance and geotectonic setting of the Palaeoproterozoic Zhongtiao Group and implications for assembly of the North China Craton: whole-rock geochemistry and detrital zircon data
Authors: Li Q. , Liu S. , Wang Z. , Shen Y. , Zhang L. , Zhang J.
Published: August 2011

Geochemical data reveal the contrasting geochemical characteristics of the metasediments in the Jiepailiang and Bizigou formations of the Palaeoproterozoic Zhongtiao Group, North China Craton. High Zr/Sc and SiO
2
/Al
2
O
3
values and especially the evolved and uniform nature of
ε
Nd
(
t
) values plus detrital zircon U–Pb ages and Hf isotopic signatures for the former are consistent with derivation from an evolved felsic source with sedimentary recycling signs. However, lower values of SiO
2
/Al
2
O
3
and Zr/Sc, and higher contents of Fe
2
O
3
* and MgO for the latter indicate input of more mafic components. These geochemical characteristics, combined with the wide range of
ε
Nd
(
t
) values, suggest that these rocks were derived in part from old continental material, dominated by felsic rocks of magmatic origin, and in part from a continental island arc, which accounts for the variable mixture of mafic components. These results suggest that the Zhongtiao Group was deposited after
c
. 2110 Ma, in a back-arc basin, behind an eastward-directed subduction system. Subsequent deformation and metamorphism reflect closure of the oceanic basin between the Eastern and Western blocks of the North China Craton, along the Trans-North China Orogen, contributing to amalgamation of the supercontinental Columbia.

Supplementary material:

Data are available at
http://www.geolsoc.org.uk/SUP18478
.
Turbidite pathways, pore-fluid pressures and productivity in the Central Wales Orefield
Authors: James David M.D.
Published: August 2011

Lodes in the Central Wales Orefield are mineralized oblique-slip normal faults that postdate the regional joints. They developed shortly after the (Acadian) deformation of the Welsh Basin in the late Early Devonian and many were reactivated with further mineralization in the early Carboniferous. Although orefield extent is clearly centred on the structural culmination around the Plynlimon Dome the major areas of lead–zinc production are strongly off-centered. These areas lie on the depositional pathways of three horizons of late Ordovician–early Silurian massive turbidite sandstones. It is argued that these basin-floor sand bodies are preferential sites of lode nucleation and that their distribution controls the size and abundance of the lodes and hence their chances to link laterally and at depth. This in turn controls their ability to capture and transmit mineralizing fluids and thus their chances of hosting large ore deposits. The prime cause of high fluid pressure gradients during the first phase of mineralization was rapid uplift of ‘tight' rock with dehydration fluids from Acadian metamorphism. Second phase fluids probably originated as seawater and were driven by convective overturn at essentially hydrostatic pressures. The stratigraphic control of lode productivity has implications for mineral exploration in such terranes.
Did shortening in thick crust cause rapid Late Cenozoic uplift in the northern Bolivian Andes?
Authors: Lamb Simon
Published: August 2011

This study explores the role of crustal shortening as a mechanism for Late Cenozoic surface uplift in the northern Bolivian Andes between
c
. 16°S and
c
. 19°S, based on new geological cross-sections across the Corque–Corocoro basin in the Altiplano (
c
. 60 km thick crust today), and published radiometric ages of volcanic rocks, in the context of a simple 2D crustal balancing model. Deformation since
c
. 10 Ma (mainly between 10 and 6 Ma) involved 28 ± 7 km of shortening across the Corque–Corocoro basin, with a wider zone of lower crustal strain, and a total of
c
. 70 km of underthrusting in the Subandes. The uplift model is supported by dynamical analyses and is identical within 2σ error to published palaeo-elevation proxies, with 2.5 ± 0.5 km of surface uplift in the Corque–Corocoro basin since
c
. 10 Ma (1.8 ± 0.5 km between 10 and 6 Ma), and 1.6 ± 0.5 km outside the basin. In this way, the Late Cenozoic palaeo-elevation record in the northern Bolivian Andes can be explained within error entirely in terms of the Late Cenozoic crustal thickening expected for the observed history of crustal shortening.
Late Cretaceous–Palaeocene continental rifting in the High Arctic: U–Pb geochronology of the Kap Washington Group volcanic sequence, North Greenland
Authors: Thorarinsson Sigurjon B. , Holm Paul M. , Tappe Sebastian , Heaman Larry M. , Tegner Christian
Published: August 2011

The Kap Washington Group volcanic sequence is exposed on the north coast of Greenland. The sequence was erupted in a continental rift setting during the opening of the Arctic Ocean and provides important geological constraints on the timing of this event. In this study we present the first isotope dilution thermal ionization mass spectrometry U–Pb zircon ages from 10 samples of trachytic to rhyolitic composition. Samples from Lockwood Island (
n
= 4) gave concordant ages between 67.2 ± 0.5 and 61.0 ± 0.3 Ma (2σ). Lavas from Kap Kane (
n
= 5) yielded concordant ages between 70.5 ± 0.3 and 69.7 ± 0.2 Ma. An ignimbrite from the Kap Washington peninsula yielded a concordant age of 68.5 ± 0.3 Ma. The Kap Washington Group sequence and similar occurrences on Ellesmere Island record a prolonged period of continental rift volcanism lasting from 92 to 58 Ma. We propose that this volcanism occurred along the margins of a nascent Eurasia Basin undergoing east–west extension linked to rifting in the Labrador Sea–Baffin Bay system.
Borehole evidence for wing-like clastic intrusion complexes on the western Norwegian margin
Authors: Jackson Christopher A.-L. , Sømme Tor O.
Published: August 2011

Data from a borehole on the Norwegian margin indicate that a strata-concordant amplitude anomaly within the Upper Cretaceous succession represents a 15 m thick sandbody that was either intruded in the subsurface or extruded on the palaeo-seabed. This observation implies that spatially related, strata-discordant anomalies are the seismic expression of sandstone dykes, thereby supporting previous geometry-based interpretations of the origin of these amplitude anomalies. Furthermore, this study indicates that thickness of an intrusion may be overestimated if based solely on seismic reflection mapping, and that this may lead to erroneous calculation of the ratio between depositional and intruded sandstone.
Spatiotemporal Models for Data-Anomaly Detection in Dynamic Environmental Monitoring Campaigns
Authors: Dereszynski Ethan W. , Dietterich Thomas G.
Published: August 2011

The ecological sciences have benefited greatly from recent advances in wireless sensor technologies. These technologies allow researchers to deploy networks of automated sensors, which can monitor a landscape at very fine temporal and spatial scales. However, these networks are subject to harsh conditions, which lead to malfunctions in individual sensors and failures in network communications. The resulting data streams often exhibit incorrect data measurements and missing values. Identifying and correcting these is time-consuming and error-prone. We present a method for real-time automated data quality control (QC) that exploits the spatial and temporal correlations in the data to distinguish sensor failures from valid observations. The model adapts to each deployment site by learning a Bayesian network structure that captures spatial relationships between sensors, and it extends the structure to a dynamic Bayesian network to incorporate temporal correlations. This model is able to flag faulty observations and predict the true values of the missing or corrupt readings. The performance of the model is evaluated on data collected by the SensorScope Project. The results show that the spatiotemporal model demonstrates clear advantages over models that include only temporal or only spatial correlations, and that the model is capable of accurately imputing corrupted values.
Multiple-Target Tracking With Binary Proximity Sensors
Authors: Singh Jaspreet , Kumar Rajesh , Madhow Upamanyu , Suri Subhash , Cagley Richard
Published: August 2011

Recent work has shown that, despite the minimal information provided by a binary proximity sensor, a network of these sensors can provide remarkably good target tracking performance. In this article, we examine the performance of such a sensor network for tracking multiple targets. We begin with geometric arguments that address the problem of counting the number of distinct targets, given a snapshot of the sensor readings. We provide necessary and sufficient criteria for an accurate target count in a one-dimensional setting, and provide a greedy algorithm that determines the minimum number of targets that is consistent with the sensor readings. While these combinatorial arguments bring out the difficulty of target counting based on sensor readings at a given time, they leave open the possibility of accurate counting and tracking by exploiting the evolution of the sensor readings over time. To this end, we develop a particle filtering algorithm based on a cost function that penalizes changes in velocity. An extensive set of simulations, as well as experiments with passive infrared sensors, are reported. We conclude that, despite the combinatorial complexity of target counting, probabilistic approaches based on fairly generic models of trajectories yield respectable tracking performance.
PDA
Authors: He Wenbo , Liu Xue , Nguyen Hoang Viet , Nahrstedt Klara , Abdelzaher Tarek
Published: August 2011

Providing efficient data aggregation while preserving data privacy is a challenging problem in wireless sensor networks research. In this article, we present two privacy-preserving data aggregation schemes for additive aggregation functions, which can be extended to approximate MAX/MIN aggregation functions. The first scheme---
Cluster-based Private Data Aggregation
(CPDA)---leverages clustering protocol and algebraic properties of polynomials. It has the advantage of incurring less communication overhead. The second scheme---
Slice-Mix-AggRegaTe
(SMART)---builds on slicing techniques and the associative property of addition. It has the advantage of incurring less computation overhead. The goal of our work is to bridge the gap between collaborative data collection by wireless sensor networks and data privacy. We assess the two schemes by privacy-preservation efficacy, communication overhead, and data aggregation accuracy. We present simulation results of our schemes and compare their performance to a typical data aggregation scheme (TAG), where no data privacy protection is provided. Results show the efficacy and efficiency of our schemes.
Analysis of Deterministic Tracking of Multiple Objects Using a Binary Sensor Network
Authors: Busnel Yann , Querzoni Leonardo , Baldoni Roberto , Bertier Marin , Kermarrec Anne-Marie
Published: August 2011

Let consider a set of anonymous moving objects to be tracked in a binary sensor network. This article studies the problem of associating deterministically a track revealed by the sensor network with the trajectory of an unique anonymous object, namely the
multiple object tracking and identification
(MOTI) problem. In our model, the network is represented by a sparse connected graph where each vertex represents a binary sensor and there is an edge between two sensors if an object can pass from one sensed region to another one without activating any other sensor. The difficulty of MOTI lies in the fact that the trajectories of two or more objects can be so close that the corresponding tracks on the sensor network can no longer be distinguished (track merging), thus confusing the deterministic association between an object trajectory and a track.

The article presents several results. We first show that MOTI cannot be solved on a general graph of ideal binary sensors even by an omniscient external observer if all the objects can freely move on the graph. Then we describe restrictions that can be imposed a priori either on the graph, on the object movements, or on both, to make the MOTI problem always solvable. In the absence of an omniscient observer, we show how our results can lead to the definition of distributed algorithms that are able to detect when the system is in a state where MOTI becomes unsolvable.
Dependable and Secure Sensor Data Storage with Dynamic Integrity Assurance
Authors: Wang Qian , Ren Kui , Yu Shucheng , Lou Wenjing
Published: August 2011

Recently, distributed data storage has gained increasing popularity for efficient and robust data management in wireless sensor networks (WSNs). The distributed architecture makes it challenging to build a highly secure and dependable yet lightweight data storage system. On the one hand, sensor data are subject to not only Byzantine failures, but also dynamic pollution attacks, as along the time the adversary may modify/pollute the stored data by compromising individual sensors. On the other hand, the resource-constrained nature of WSNs precludes the applicability of heavyweight security designs. To address the challenge, in this article we propose a novel dependable and secure data storage scheme with dynamic integrity assurance. Based on the principle of secret sharing and erasure coding, we first propose a hybrid share generation and distribution scheme to achieve reliable and fault-tolerant initial data storage by providing redundancy for original data components. To further dynamically ensure the integrity of the distributed data shares, we then propose an efficient data integrity verification scheme exploiting the techniques of algebraic signature and spot-checking. The proposed scheme enables individual sensors to verify in one protocol execution the correctness of all the pertaining data shares simultaneously in the absence of the original data. Extensive security analysis shows that the proposed scheme has strong resistance against various data pollution attacks. The efficiency of the scheme is demonstrated by experiments on sensor platforms Tmote Sky and iMote2.
Remix nation
Authors: Tushnet Rebecca
Published: August 2011

Assessing the threat the anticircumvention provisions of the Digital Millennium Copyright Act pose for fair use.
In praise of 'Wilkes, Wheeler, and Gill'
Authors: Campbell-Kelly Martin
Published: August 2011

Reflections on the first textbook on programming.
Corporate social responsibility and global IT outsourcing
Authors: Babin Ron , Briggs Steve , Nicholson Brian
Published: August 2011

How to improve IT outsourcing relationships while doing good for society.
ACM CTO roundtable on mobile devices in the enterprise
Authors: Creeger Mache
Published: August 2011

Finding solutions as growth and fragmentation complicate mobile device support.
Arrogance in business planning
Authors: Vixie Paul
Published: August 2011

Technology business plans that assume no competition---ever.
Satisfiability modulo theories
Authors: De Moura Leonardo , Bjørner Nikolaj
Published: August 2011

Checking the satisfiability of logical formulas, SMT solvers scale orders of magnitude beyond custom ad hoc solvers.
Calculating and improving ROI in software and system programs
Authors: Cantor Murray
Published: August 2011

The investment value of innovation follows from a technology's uncertain net present value and derived ROI calculations.
A model for spectra-based software diagnosis
Authors: Naish Lee , Lee Hua Jie , Ramamohanarao Kotagiri
Published: August 2011

This article presents an improved approach to assist diagnosis of failures in software (fault localisation) by ranking program statements or blocks in accordance with to how likely they are to be buggy. We present a very simple single-bug program to model the problem. By examining different possible execution paths through this model program over a number of test cases, the effectiveness of different proposed spectral ranking methods can be evaluated in idealised conditions. The results are remarkably consistent to those arrived at empirically using the Siemens test suite and Space benchmarks. The model also helps identify groups of metrics that are equivalent for ranking. Due to the simplicity of the model, an optimal ranking method can be devised. This new method out-performs previously proposed methods for the model program, the Siemens test suite and Space. It also helps provide insight into other ranking methods.
FlagRemover
Authors: Binkley David W. , Harman Mark , Lakhotia Kiran
Published: August 2011

Search-Based Testing is a widely studied technique for automatically generating test inputs, with the aim of reducing the cost of software engineering activities that rely upon testing. However, search-based approaches degenerate to random testing in the presence of flag variables, because flags create spikes and plateaux in the fitness landscape. Both these features are known to denote hard optimization problems for all search-based optimization techniques. Several authors have studied flag removal transformations and fitness function refinements to address the issue of flags, but the problem of loop-assigned flags remains unsolved. This article introduces a testability transformation along with a tool that transforms programs with loop-assigned flags into flag-free equivalents, so that existing search-based test data generation approaches can successfully be applied. The article presents the results of an empirical study that demonstrates the effectiveness and efficiency of the testability transformation on programs including those made up of open source and industrial production code, as well as test data generation problems specifically created to denote hard optimization problems.
A survey on representation, composition and application of preferences in database systems
Authors: Stefanidis Kostas , Koutrika Georgia , Pitoura Evaggelia
Published: August 2011

Preferences have been traditionally studied in philosophy, psychology, and economics and applied to decision making problems. Recently, they have attracted the attention of researchers in other fields, such as databases where they capture soft criteria for queries. Databases bring a whole fresh perspective to the study of preferences, both computational and representational. From a representational perspective, the central question is how we can effectively represent preferences and incorporate them in database querying. From a computational perspective, we can look at how we can efficiently process preferences in the context of database queries. Several approaches have been proposed but a systematic study of these works is missing. The purpose of this survey is to provide a framework for placing existing works in perspective and highlight critical open challenges to serve as a springboard for researchers in database systems. We organize our study around three axes: preference representation, preference composition, and preference query processing.
Application-specific signatures for transactional memory in soft processors
Authors: Labrecque Martin , Jeffrey Mark C. , Steffan J. Gregory
Published: August 2011

As reconfigurable computing hardware and in particular FPGA-based systems-on-chip comprise an increasing number of processor and accelerator cores, supporting sharing and synchronization in a way that is scalable and easy to program becomes a challenge.
Transactional Memory
(TM) is a potential solution to this problem, and an FPGA-based system provides the opportunity to support TM in hardware (HTM). Although there are many proposed approaches to HTM support for ASICs, these do not necessarily map well to FPGAs. In particular in this work we demonstrate that while
signature
-based conflict detection schemes (essentially bit-vectors) should intuitively be a good match to the bit parallelism of FPGAs, previous approaches result in unacceptable multicycle stalls, operating frequencies, or false-conflict rates. Capitalizing on the reconfigurable nature of FPGA-based systems, we propose an application-specific signature mechanism for HTM conflict detection. Our evaluation uses real and projected FPGA-based soft multiprocessor systems that support HTM and implement threaded, shared-memory network packet processing applications. We find that our application-specific approach: (i) maintains a reasonable operating frequency of 125 MHz, (ii) achieves a 9% to 71% increase in packet throughput relative to signatures with bit selection on a 2-thread architecture, and (iii) allows our HTM to achieve 6%, 54%, and 57% increases in packet throughput on an 8-thread architecture versus a baseline lock-based synchronization for three of four packet processing applications studied, due to reduced false synchronization.
Optimizing memory bandwidth use and performance for matrix-vector multiplication in iterative methods
Authors: Boland David , Constantinides George A.
Published: August 2011

Computing the solution to a system of linear equations is a fundamental problem in scientific computing, and its acceleration has drawn wide interest in the FPGA community [Morris et al. 2006; Zhang et al. 2008; Zhuo and Prasanna 2006]. One class of algorithms to solve these systems, iterative methods, has drawn particular interest, with recent literature showing large performance improvements over General-Purpose Processors (GPPs) [Lopes and Constantinides 2008]. In several iterative methods, this performance gain is largely a result of parallelization of the matrix-vector multiplication, an operation that occurs in many applications and hence has also been widely studied on FPGAs [Zhuo and Prasanna 2005; El-Kurdi et al. 2006]. However, whilst the performance of matrix-vector multiplication on FPGAs is generally I/O bound [Zhuo and Prasanna 2005], the nature of iterative methods allows the use of on-chip memory buffers to increase the bandwidth, providing the potential for significantly more parallelism [deLorimier and DeHon 2005]. Unfortunately, existing approaches have generally only either been capable of solving large matrices with limited improvement over GPPs [Zhuo and Prasanna 2005; El-Kurdi et al. 2006; deLorimier and DeHon 2005], or achieve high performance for relatively small matrices [Lopes and Constantinides 2008; Boland and Constantinides 2008]. This article proposes hardware designs to take advantage of symmetrical and banded matrix structure, as well as methods to optimize the RAM use, in order to both increase the performance and retain this performance for larger-order matrices.
Application-Specific FPGA using heterogeneous logic blocks
Authors: Parvez Husain , Marrakchi Zied , Kilic Alp , Mehrez Habib
Published: August 2011

This work presents a new automatic mechanism to explore the solution space between Field Programmable Gate Arrays (FPGAs) and Application-Specific Integrated Circuits (ASICs). This new solution is termed as an Application-Specific Inflexible FPGA (ASIF) [Parvez et al. 2009]. An ASIF can be considered as an FPGA with reduced flexibility, or as a reconfigurable ASIC that can implement a set of application circuits which will operate at mutually exclusive times. Execution of different application circuits can be switched by loading their respective bitstream on an ASIF. An ASIF that is reduced from a heterogeneous FPGA is termed as a heterogeneous ASIF. It is shown that a standard-cell-based heterogeneous ASIF for a set of 10 opencore application circuits is 9.6 times smaller than a single-driver mesh-based heterogeneous FPGA. The area gap between ASIC and ASIF is not too significant; however, it can be reduced by designing repeatedly used components of ASIF in full-custom. Unlike an ASIC, an ASIF is a reprogrammable device that can be used to reprogram new or modified circuits at a limited scale.
An FPGA-based accelerator for LambdaRank in Web search engines
Authors: Yan Jing , Xu Ning-YI , Cai Xiong-FEI , Gao Rui , Wang Yu , Luo Rong , Hsu Feng-HSIUNG
Published: August 2011

In modern Web search engines, Neural Network (NN)-based learning to rank algorithms is intensively used to increase the quality of search results. LambdaRank is one such algorithm. However, it is hard to be efficiently accelerated by computer clusters or GPUs, because: (i) the cost function for the ranking problem is much more complex than that of traditional Back-Propagation(BP) NNs, and (ii) no coarse-grained parallelism exists in the algorithm. This article presents an FPGA-based accelerator solution to provide high computing performance with low power consumption. A compact deep pipeline is proposed to handle the complex computing in the batch updating. The area scales linearly with the number of hidden nodes in the algorithm. We also carefully design a data format to enable streaming consumption of the training data from the host computer. The accelerator shows up to 15.3X (with PCIe x4) and 23.9X (with PCIe x8) speedup compared with the pure software implementation on datasets from a commercial search engine.
SHMEM+
Authors: Aggarwal Vikas , George Alan D. , Yoon Changil , Yalamanchili Kishore , Lam Herman
Published: August 2011

Reconfigurable Computing (RC) systems based on FPGAs are becoming an increasingly attractive solution to building parallel systems of the future. Applications targeting such systems have demonstrated superior performance and reduced energy consumption versus their traditional counterparts based on microprocessors. However, most of such work has been limited to small system sizes. Unlike traditional HPC systems, lack of integrated, system-wide, parallel-programming models and languages presents a significant design challenge for creating applications targeting scalable, reconfigurable HPC systems. In this article, we extend the traditional Partitioned Global Address Space (PGAS) model to provide a multilevel integration of memory, which simplifies development of parallel applications for such systems and improves developer productivity. The new multilevel-PGAS programming model captures the unique characteristics of reconfigurable HPC systems, such as the existence of multiple levels of memory hierarchy and heterogeneous computation resources. Based on this model, we extend and adapt the SHMEM communication library to become what we call SHMEM+, the first known SHMEM library enabling coordination between FPGAs and CPUs in a reconfigurable, heterogeneous HPC system. Applications designed with SHMEM+ yield improved developer productivity compared to current methods of multidevice RC design and exhibit a high degree of portability. In addition, our design of SHMEM+ library itself is portable and provides peak communication bandwidth comparable to vendor-proprietary versions of SHMEM. Application case studies are presented to illustrate the advantages of SHMEM+.
An analytical model for multilevel performance prediction of Multi-FPGA systems
Authors: Holland Brian , George Alan D. , Lam Herman , Smith Melissa C.
Published: August 2011

Power limitations in semiconductors have made explicitly parallel device architectures such as Field-Programmable Gate Arrays (FPGAs) increasingly attractive for use in scalable systems. However, mitigating the significant cost of FPGA development requires efficient design-space exploration to plan and evaluate a range of potential algorithm and platform choices
prior
to implementation. The authors propose the RC Amenability Test for Scalable Systems (RATSS), an analytical model which enables straightforward, fast, and reasonably accurate performance prediction prior to implementation by extending current modeling concepts to multi-FPGA designs. RATSS provides a comprehensive strategic model to evaluate applications based on the computation and communication requirements of the algorithm and capabilities of the FPGA platform. The RATSS model targets data-parallel applications on current scalable FPGA systems. Three case studies with RATSS demonstrate nearly 90% prediction accuracy as compared to corresponding implementations.
Leveraging reconfigurability in the hardware/software codesign process
Authors: Shannon Lesley , Chow Paul
Published: August 2011

Current technology allows designers to implement complete embedded computing systems on a single FPGA. Using an FPGA as the implementation platform introduces greater flexibility into the design process and allows a new approach to embedded system design. Since there is no cost to reprogramming an FPGA, system performance can be measured on-chip in the runtime environment and the system's architecture can be altered based on an evaluation of the data to meet design requirements.

In this article, we discuss a new hardware/software codesign methodology tailored to reconfigurable platforms and a design infrastructure created to incorporate on-chip design tools. This methodology utilizes the FPGA's reconfigurability during the design process to profile and verify system performance, thereby reducing system design time. Our current design infrastructure includes: a system specification tool, two on-chip profiling tools, and an on-chip system verification tool.
Digital reconstruction of pavilions described in an ancient Indian architectural treatise
Authors: Das Vinay Mohan , Garg Yogesh K.
Published: August 2011

Digital documentation and reconstruction is a comparatively recent phenomenon in the history of architectural heritage documentation and conservation. It has emerged as a result of technological development, especially in computer applications that have extended our capabilities to cope up with the knowledge systems of increasing broad range and complexity.

For most people, including architects, heritage and conservation mean historical buildings and their conservation. However, there is another facet to it that is not well recognized; the area of “literary architectural heritage, ” that is, the literature on historical architecture. In the literary architectural heritage of India, many architectural treatises are available for graphical documentation of the built examples described in them. This article aims to present digital graphical documentation of the pavilions described in the
Mayamatam
, an architectural treatise of ancient India.

Research in this area will enrich the knowledge base of architecture. Having this information in a digital format like CAD drawings, virtual 3D models would result in better communication, storage, and retrieval for editing, modifications, and analysis. This digital documentation and representation provides the possibility of being used as a teaching aid for students and architects and also for recovering lost knowledge in the context of partially destroyed structures. For architects and designers, who constantly search for new ways, the digital presentation of ancient Indian pavilions provide a design tool for discovering new patterns to be used in contemporary architecture.
Kolmogorov Complexity in Randomness Extraction
Authors: Hitchcock John M. , Pavan A. , Vinodchandran N. V.
Published: August 2011

We clarify the role of Kolmogorov complexity in the area of randomness extraction. We show that a computable function is an almost randomness extractor if and only if it is a Kolmogorov complexity extractor, thus establishing a fundamental equivalence between two forms of extraction studied in the literature: Kolmogorov extraction and randomness extraction. We present a distribution
Mk
based on Kolmogorov complexity that is complete for randomness extraction in the sense that a computable function is an almost randomness extractor if and only if it extracts randomness from
Mk
.
On the Power of Isolation in Planar Graphs
Authors: Kulkarni Raghav
Published: August 2011

We study (deterministic) isolation for certain structures in directed and undirected planar graphs. The motivation for undertaking such a study comes from recent positive results on this topic. For example: Bourke et al. [2009] isolate a directed path in planar graphs and subsequently Datta et al. [2010b] isolate a perfect matching in bipartite planar graphs. Our first observation is that sufficiently strong (and plausible) isolations for certain structures in planar graphs would have strong consequences such as:
NL
⊆ ⊕
L
, Bipartite-Matching ∈
NC
, and
NP
⊆ ⊕
P
. Our second observation is that although we do not yet have such strong isolations for arbitrary planar graphs, we do have them for bipartite planar graphs, that is,
non-bipartiteness
is the main bottleneck.
On the design of perturbation-resilient atomic commit protocols for mobile transactions
Authors: Ayari Brahim , Khelil Abdelmajid , Suri Neeraj
Published: August 2011

Distributed mobile transactions utilize commit protocols to achieve atomicity and consistent decisions. This is challenging, as mobile environments are typically characterized by frequent perturbations such as network disconnections and node failures. On one hand environmental constraints on mobile participants and wireless links may increase the resource blocking time of fixed participants. On the other hand frequent node and link failures complicate the design of atomic commit protocols by increasing both the transaction abort rate and resource blocking time. Hence, the deployment of classical commit protocols (such as two-phase commit) does not reasonably extend to distributed infrastructure-based mobile environments driving the need for perturbation-resilient commit protocols.

In this article, we comprehensively consider and classify the perturbations of the wireless infrastructure-based mobile environment according to their impact on the outcome of commit protocols and on the resource blocking times. For each identified perturbation class a commit solution is provided. Consolidating these subsolutions, we develop a family of fault-tolerant atomic commit protocols that are tunable to meet the desired perturbation needs and provide minimized resource blocking times and optimized transaction commit rates. The framework is also evaluated using simulations and an actual testbed deployment.
Emulating human observers with bayesian binning
Authors: Endres Dominik , Christensen Andrea , Omlor Lars , Giese Martin A.
Published: August 2011

Natural body movements arise in the form of temporal sequences of individual actions. During visual action analysis, the human visual system must accomplish a temporal segmentation of the action stream into individual actions. Such temporal segmentation is also essential to build hierarchical models for action synthesis in computer animation. Ideally, such segmentations should be computed automatically in an unsupervised manner. We present an unsupervised segmentation algorithm that is based on Bayesian Binning (BB) and compare it to human segmentations derived from psychophysical data. BB has the advantage that the observation model can be easily exchanged. Moreover, being an exact Bayesian method, BB allows for the automatic determination of the number and positions of segmentation points. We applied this method to motion capture sequences from martial arts and compared the results to segmentations provided by humans from movies that showed characters that were animated with the motion capture data. Human segmentation was then assessed by an interactive adjustment paradigm, where participants had to indicate segmentation points by selection of the relevant frames. Results show a good agreement between automatically generated segmentations and human performance when the trajectory segments between the transition points were modeled by polynomials of at least third order. This result is consistent with theories about differential invariants of human movements.
Evolving spiking networks with variable memristors
Authors: Howard Gerard , Gale Ella , Bull Larry , de Lacy Costello Ben , Adamatzky Andy
Published: August 2011

This paper presents a spiking neuro-evolutionary system which implements memristors as neuromodulatory connections, i.e. whose weights can vary during a trial. The evolutionary design process exploits parameter self-adaptation and a constructionist approach, allowing the number of neurons, connection weights, and inter-neural connectivity pattern to be evolved for each network. Additionally, each memristor has its own conductance profile, which alters the neuromodulatory behaviour of the memristor and may be altered during the application of the GA. We demonstrate that this approach allows the evolutionary process to discover beneficial memristive behaviours at specific points in the networks. We evaluate our approach against two phenomenological realworld memristive implementations, a theoretical "linear memristor", and a system containing standard connections only. Performance is evaluated on a simulated robotic navigation task.
An Iron Regulatory Gene Signature Predicts Outcome in Breast Cancer
Authors: Miller Lance D. , Coffman Lan G. , Chou Jeff W. , Black Michael A. , Bergh Jonas , D'Agostino Ralph , Torti Suzy V. , Torti Frank M.
Published: August 2011

Changes in iron regulation characterize the malignant state. However, the pathways that effect these changes and their specific impact on prognosis remain poorly understood. We capitalized on publicly available microarray datasets comprising 674 breast cancer cases to systematically investigate how expression of genes related to iron metabolism is linked to breast cancer prognosis. Of 61 genes involved in iron regulation, 49% were statistically significantly associated with distant metastasis-free survival. Cases were divided into test and training cohorts, and the supervised principal component method was used to stratify cases into risk groups. Optimal risk stratification was achieved with a model comprising 16 genes, which we term the iron regulatory gene signature (IRGS). Multivariable analysis revealed that the IRGS contributes information not captured by conventional prognostic indicators (HR = 1.61; 95% confidence interval: 1.16–2.24; P = 0.004). The IRGS successfully stratified homogeneously treated patients, including ER+ patients treated with tamoxifen monotherapy, both with (P = 0.006) and without (P = 0.03) lymph node metastases. To test whether multiple pathways were embedded within the IRGS, we evaluated the performance of two gene dyads with known roles in iron biology in ER+ patients treated with tamoxifen monotherapy (n = 371). For both dyads, gene combinations that minimized intracellular iron content [anti-import: TFRCLow/HFEHigh; or pro-export: SLC40A1 (ferroportin)High/HAMPLow] were associated with favorable prognosis (P < 0.005). Although the clinical utility of the IRGS will require further evaluation, its ability to both identify high-risk patients within traditionally low-risk groups and low-risk patients within high-risk groups has the potential to affect therapeutic decision making. Cancer Res; 71(21); 6728–37. ©2011 AACR.
Proteolytic Activation of Pro-Macrophage-Stimulating Protein by Hepsin
Authors: Ganesan Rajkumar , Kolumam Ganesh A. , Lin S. Jack , Xie Ming-Hong , Santell Lydia , Wu Thomas D. , Lazarus Robert A. , Chaudhuri Amitabha , Kirchhofer Daniel
Published: August 2011

Macrophage-stimulating protein (MSP) is a plasminogen-related growth factor and ligand for the receptor tyrosine kinase RON. The MSP/RON system promotes wound healing and invasive tumor growth and suppresses proinflammatory immune response. MSP binding to RON requires proteolytic conversion of the inactive single-chain form (pro-MSP) into the disulfide-linked α/β heterodimer. The pro-MSP cleavage sequence (Ser-Lys-Leu-Arg483↓Val484) closely matches the substrate recognition sequences of hepsin, a type II transmembrane serine protease, that is overexpressed in several cancers. Here, we show that recombinant hepsin cleaves pro-MSP at the consensus site Arg483-Val484 with superior efficiency compared with the known activators MT-SP1 and hepatocyte growth factor activator (HGFA). At least 50% of pro-MSP was processed within 1 hour at a hepsin concentration of 2.4 nmol/L and at a molar enzyme to substrate ratio of 1:500. An uncleavable single-chain variant of MSP weakly bound to a RON–Fc fusion protein, whereas hepsin-cleaved MSP bound with a KD of 10.3 nmol/L, suggesting that the high-affinity binding site in MSP β-chain was properly formed. LNCaP prostate cancer cells overexpressing hepsin on the cell surface efficiently activated pro-MSP, which was blocked by a specific anti-hepsin antibody. Incubation of pro-MSP with hepsin led to robust RON-mediated phosphorylation of mitogen-activated protein kinase, ribosomal S6 protein, and Akt in human A2780 ovarian carcinoma cells stably expressing RON protein. In macrophages, pro-MSP with hepsin induced chemotaxis and attenuated lipopolysaccharide-dependent production of nitric oxide. These findings suggest that the MSP/RON signaling pathway may be regulated by hepsin in tissue homeostasis and in disease pathologies, such as in cancer and immune disorders. Mol Cancer Res; 9(9); 1175–86. ©2011 AACR.
ADAM12 Produced by Tumor Cells Rather than Stromal Cells Accelerates Breast Tumor Progression
Authors: Fröhlich Camilla , Nehammer Camilla , Albrechtsen Reidar , Kronqvist Pauliina , Kveiborg Marie , Sehara-Fujisawa Atsuko , Mercurio Arthur M. , Wewer Ulla M.
Published: August 2011

Expression of ADAM12 is low in most normal tissues but is markedly increased in numerous human cancers, including breast carcinomas. We have previously shown that overexpression of ADAM12 accelerates tumor progression in a mouse model of breast cancer (PyMT). In this study, we found that ADAM12 deficiency reduces breast tumor progression in the PyMT model. However, the catalytic activity of ADAM12 seems to be dispensable for its tumor-promoting effect. Interestingly, we show that ADAM12 endogenously expressed in tumor-associated stroma in the PyMT model does not influence tumor progression, but that ADAM12 expression by tumor cells is necessary for tumor progression in these mice. This finding is consistent with our observation that in human breast carcinoma, ADAM12 is almost exclusively located in tumor cells and, only rarely, seen in the tumor-associated stroma. We hypothesized, however, that the tumor-associated stroma may stimulate ADAM12 expression in tumor cells, on the basis of the fact that TGF-β1 stimulates ADAM12 expression and is a well-known growth factor released from tumor-associated stroma. TGF-β1 stimulation of ADAM12-negative Lewis lung tumor cells induced ADAM12 synthesis, and growth of these cells in vivo induced more than 200-fold increase in ADAM12 expression. Our observation that ADAM12 expression is significantly higher in the terminal duct lobular units (TDLU) adjacent to human breast carcinoma compared with TDLUs found in normal breast tissue supports our hypothesis that tumor-associated stroma triggers ADAM12 expression. Mol Cancer Res; 9(11); 1449–61. ©2011 AACR.
Long-Term Outcome of Patients With Isolated Thin Discrete Subaortic Stenosis Treated by Balloon Dilation
Authors: de Lezo José Suárez , Romero Miguel , Segura José , Pan Manuel , de Lezo Javier Suárez , Pavlovic Djordje , Mazuelos Francisco , Delgado Mónica , Mesa Dolores
Published: August 2011

Background—

Transluminal balloon tearing of the membrane in a thin discrete subaortic stenosis is an alternative to membrane surgical resection. However, the long-term outcome of patients with isolated thin discrete subaortic stenosis treated by transluminal balloon tearing remains unknown.

Methods and Results—

This 25-year study describes findings from 76 patients with isolated thin discrete subaortic stenosis who underwent percutaneous transluminal balloon tearing of the membrane and were followed up for a mean period of 16±6 years. The age at presentation had a wide range (2–67 years). The mean age at treatment was 19±16 years. Immediately after treatment, the subvalvular gradient decreased from 70±27 to 18±12 mm Hg (
P
<0.001). No significant postprocedural aortic regurgitation was observed. After a mean follow-up time of 16±6 years, 11 patients (15%) developed restenosis, 3 patients (4%) progressed to muscular obstructive disease, and 1 patient (1.3%) developed a new distant obstructive membrane. Twelve patients (16%) were redilated at a mean of 5±3 years after their first treatment, and 4 patients (5%) underwent surgery at a mean of 3±2 years after their first treatment. Fifty-eight patients (77%) remained alive and free of redilation or surgery at follow-up. Larger annulus diameter and thinner membranes were independent factors associated with better long-term results.

Conclusions—

Most patients (77%) with isolated thin discrete subaortic stenosis treated with transluminal balloon tearing of the membrane had sustained relief at subsequent follow-ups without restenosis, the need for surgery, progression to muscular obstructive disease, or an increase in the degree of aortic regurgitation.
Exercise Oscillatory Ventilation in Systolic Heart Failure
Authors: Murphy Ryan M. , Shah Ravi V. , Malhotra Rajeev , Pappagianopoulos Paul P. , Hough Stacyann S. , Systrom David M. , Semigran Marc J. , Lewis Gregory D.
Published: August 2011

Background—

Exercise oscillatory ventilation (EOV) is a noninvasive parameter that potently predicts outcomes in systolic heart failure (HF). However, mechanistic insights into EOV have been limited by the absence of studies relating EOV to invasive hemodynamic measurements and blood gases performed during exercise.

Methods and Results—

Fifty-six patients with systolic HF (mean±SEM age, 59±2 years; left ventricular ejection fraction, 30±1%) and 19 age-matched control subjects were studied with incremental cardiopulmonary exercise testing. Fick cardiac outputs, filling pressures, and arterial blood gases were measured at 1-minute intervals during exercise. We detected EOV in 45% of HF (HF+EOV) patients and in none of the control subjects. The HF+EOV group did not differ from the HF patients without EOV (HF−EOV) in age, sex, body mass index, left ventricular ejection fraction, or origin of HF. Univariate predictors of the presence of EOV in HF, among measurements performed during exercise, included higher right atrial pressure and pulmonary capillary wedge pressure and lower cardiac index (CI) but not Pa
co
2
or Pa
o
2
. Multivariate logistic regression identified that low exercise CI is the strongest predictor of EOV (odds ratio, 1.39 for each 1.0-L · min
−1
· m
−2
decrement in CI; 95% confidence interval, 1.14–1.70;
P
=0.001). Among HF patients with EOV, exercise CI was inversely related to EOV cycle length (
R
=−0.71) and amplitude (
R
=−0.60; both
P
<0.001). In 11 HF+EOV subjects treated with 12 weeks of sildenafil, EOV cycle length and amplitude decreased proportionately to increases in CI.

Conclusion—

Exercise oscillatory ventilation is closely related to reduced CI and elevated filling pressures during exercise and may be an important surrogate for exercise-induced hemodynamic impairment in HF patients.

Clinical Trial Registration—

URL:
http://www.clinicaltrials.gov
. Unique identifier: NCT00309790.