ppxscal/embedding_network huggingface dataset:
Model investigation about the potential of C band SAR in herbaceous wetlands flood monitoring
Authors: F. M. Grings, P. Ferrazzoli, H. Karszenbaum, M. Salvia, P. Kandus, J. C. Jacobo-Berlles, Pablo Perna
Venue: International Journal of Remote Sensing (2008)

Wetlands are areas where the presence of water at or near the soil surface drives the natural system. Imaging radars (SARs) have distinct characteristics which make them of significant value for monitoring and mapping wetland inundation dynamics. The presence or absence of water (which has a much higher dielectric constant than dry or wet soil) in wetlands may significantly alter the signal detected from these areas depending on the dominant vegetation type, density, and height. The objective of this paper is to present our current research efforts to explain and correctly simulate the radar response of wetland vegetation/inundation mixtures, and use simulations as an aid for retrieval applications. The radar response of junco marshes under different flood conditions and vegetation stages is analysed using a set of 13 multipolarization ENVISAT ASAR scenes acquired over the Parana River Delta marshes during the period 2003-2005. The main aspect of the approach followed is the simulation of SAR wave interactions with vegetation and water, using an adapted and improved version of the EM model developed at Tor Vergata University. The results obtained indicate that with the refined EM model, it is possible to represent with a good accuracy VV and HH SAR responses of junco marshes for a variety of environmental conditions. Further work and data are needed to explain measured HV backscattering. The general agreement obtained between simulations and observations permitted the development of a simple retrieval scheme, and estimates of water level below the canopy were obtained for different environmental conditions. RMS errors of forward simulations and retrievals are reported and discussed.
A Wizard of Oz study for an AR multimodal interface
Authors: Minkyung Lee, Mark Billinghurst
Venue: Proceedings of the 10th international conference on Multimodal interfaces (2008)

In this paper we describe a Wizard of Oz (WOz) user study of an Augmented Reality (AR) interface that uses multimodal input (MMI) with natural hand interaction and speech commands. Our goal is to use a WOz study to help guide the creation of a multimodal AR interface which is most natural to the user. In this study we used three virtual object arranging tasks with two different display types (a head mounted display, and a desktop monitor) to see how users used multimodal commands, and how different AR display conditions affect those commands. The results provided valuable insights into how people naturally interact in a multimodal AR scene assembly task. For example, we discovered the optimal time frame for fusing speech and gesture commands into a single command. We also found that display type did not produce a significant difference in the type of commands used. Using these results, we present design recommendations for multimodal interaction in AR environments.
Characterizing the miss sequence of the LRU cache
Authors: Predrag R. Jelenković, Xiaozhu Kang
Venue: ACM SIGMETRICS Performance Evaluation Review (2008)

Renewed interest in caching systems stems from their wide-spread use for reducing the document download latency over the Internet. Since caches are usually organized in a hierarchical manner, it is important to study the performance properties of tandem caches. The first step in understanding this problem is to characterize the miss stream from one single cache since it represents the input to the next level cache. In this regard, we discover that the miss stream from one single cache is approximated well by the superposition of a number of asymptotically independent renewal processes. Interestingly, when this weakly correlated miss sequence is fed into another cache, this barely observable correlation can lead to measurably different caching performance when compared to the independent reference model. This result is likely to enable the development of a rigorous analysis of the tandem cache performance.
'Maximal effective baseline' for conventional SAR interferometry
Authors: Z. Chang, J. Zhang, H. Gong, J. Zhang, W. Zhao
Venue: International Journal of Remote Sensing (2007)

As is well known, perpendicular baselines coming close to the critical baseline will most likely give poor results or even not give any results in conventional SAR interferometry. In the present paper, we put forward a new concept named 'maximal effective baseline' for conventional SAR interferometry, which is intrinsically different from the concept of 'critical baseline'. It is defined as 'an upper limit of perpendicular baseline for specific SAR system, and it is impossible to obtain necessary coherence to implement conventional SAR interferometry as long as the perpendicular baseline of SAR image pair is beyond this upper limit'. Then, the theoretical approach to determine the maximal effective baseline for conventional SAR interferometry is presented, and the concrete values of maximal effective baselines for ERS1/2 and JERS are yielded by analysing various decorrelation sources. Further more, some InSAR experiments have been made to confirm the results. The 'maximal effective baseline' for conventional SAR interferometry is of practical significance in improving the working efficiency of conventional SAR interferometry.
A motion observable representation using color correlogram and its applications to tracking
Authors: Qi Zhao, Hai Tao
Venue: Computer Vision and Image Understanding (2009)

This paper presents a special form of color correlogram as representation for object tracking and carries out a motion observability analysis to obtain the optimal correlogram in a kernel based tracking framework. Compared with the color histogram, where the position information of each pixel is ignored, a simplified color correlogram (SCC) representation encodes the spatial information explicitly and enables an estimation algorithm to recover the object orientation. In this paper, based on the SCC representation, the mean shift algorithm is developed in a translation-rotation joint domain to track the positions and orientations of objects. The ability of the SCC in detecting and estimating object motion is analyzed and a principled way to obtain the optimal SCC as object representation is proposed to ensure reliable tracking. Extensive experimental results demonstrate SCC as a viable object representation for tracking.
Row-wise parallel predicate evaluation
Authors: Ryan Johnson, Vijayshankar Raman, Richard Sidle, Garret Swart
Venue: Proceedings of the VLDB Endowment (2008)

Table scans have become more interesting recently due to greater use of ad-hoc queries and greater availability of multi-core, vector-enabled hardware. Table scan performance is limited by value representation, table layout, and processing techniques. In this paper we propose a new layout and processing technique for efficient one-pass predicate evaluation. Starting with a set of rows with a fixed number of bits per column, we append columns to form a set of banks and then pad each bank to a supported machine word length, typically 16, 32, or 64 bits. We then evaluate partial predicates on the columns of each bank, using a novel evaluation strategy that evaluates column level equality, range tests, IN-list predicates, and conjuncts of these predicates, simultaneously on multiple columns within a bank, and on multiple rows within a machine register. This approach outperforms pure column stores, which must evaluate the partial predicates one column at a time. We evaluate and compare the performance and representation overhead of this new approach and several proposed alternatives.
A physically based satellite rainfall estimation method using fluid dynamics modelling
Authors: F. J. Tapiador
Venue: International Journal of Remote Sensing (2008)

A cloud motion winds (CMW) method is presented for improving quantitative rainfall estimation advection schemes that use both infrared (IR) and passive microwave (PMW) satellite data. Advection schemes are used to provide quantitative rainfall estimates by combining more direct PMW rainfall estimates with more frequent IR cloud top temperature measures using a two-step technique: (1) PMW estimates are transported along CMW trajectories calculated with an advection scheme at subpixel resolution; and (2) PMW estimates are calibrated using the IR gradient along those trajectories. These schemes outperform traditional methods of satellite rainfall estimation but no clear physical basis for the procedure has yet been described. Here, the physical basis for the image processing techniques used in advection techniques is described. It is shown that geostationary satellite-derived CMW from IR sensors can be modelled in terms of fluid dynamics using Navier-Stokes equations. This approach allows for modelling the problem as equivalent to the flow of a brightness temperature field, also providing subpixel resolution and unlimited rotation/deformation possibilities. The method is illustrated with rainfall estimates from a numerical weather prediction (NWP) model and with 3-hourly PMW products as simulation data, obtaining consistent results.
Adaptive insertion policies for managing shared caches
Authors: Aamer Jaleel, William Hasenplaugh, Moinuddin Qureshi, Julien Sebot, Simon Steely,  Jr., Joel Emer
Venue: Proceedings of the 17th international conference on Parallel architectures and compilation techniques (2008)

Chip Multiprocessors (CMPs) allow different applications to concurrently execute on a single chip. When applications with differing demands for memory compete for a shared cache, the conventional LRU replacement policy can significantly degrade cache performance when the aggregate working set size is greater than the shared cache. In such cases, shared cache performance can be significantly improved by preserving the entire working set of applications that can co-exist in the cache and preserving some portion of the working set of the remaining applications. This paper investigates the use of adaptive insertion policies to manage shared caches. We show that directly extending the recently proposed dynamic insertion policy (DIP) is inadequate for shared caches since DIP is unaware of the characteristics of individual applications. We propose Thread-Aware Dynamic Insertion Policy (TADIP) that can take into account the memory requirements of each of the concurrently executing applications. Our evaluation with multi-programmed workloads for 2-core, 4-core, 8-core, and 16-core CMPs show that a TADIP-managed shared cache improves overall throughput by as much as 94%, 64%, 26%, and 16% respectively (on average 14%, 18%, 15%, and 17%) over the baseline LRU policy. The performance benefit of TADIP is 2.6x compared to DIP and 1.3x compared to the recently proposed Utility-based Cache Partitioning (UCP) scheme. We also show that a TADIP-managed shared cache provides performance benefits similar to doubling the size of an LRU-managed cache. Furthermore, TADIP requires a total storage overhead of less than two bytes per core, does not require changes to the existing cache structure, and performs similar to LRU for LRU friendly workloads.
Multi-objective flexible job shop schedule: Design and evaluation by simulation modeling
Authors: Li-Ning Xing, Ying-Wu Chen, Ke-Wei Yang
Venue: Applied Soft Computing (2009)

Flexible job shop schedule is very important in both fields of combinatorial optimization and production management. In this paper, a simulation model is presented to solve the multi-objective flexible job shop scheduling problem. The proposed model has been coded by Matlab which is a special mathematical computation language. After modeling the pending problem, the model is validated by five representative instances based on practical data. The results obtained from the computational study have shown that the proposed approach is a feasible and effective approach for the multi-objective flexible job shop scheduling problem.
Household type load's effects on photovoltaic systems
Authors: Nazmi Ekren, Nevzat Onat, Safak Saglam
Venue: WSEAS Transactions on Circuits and Systems (2008)

The solar energy is one of the most important energy sources available because, besides the fact that it is not polluting the environment and it helps to the reduction of green house effect, it is free of charge and it can be easily converted to other forms of energy. Clean and renewable energy production is getting more attractive due to global warming, environmental factors and decrease in conventional energy sources. Photovoltaic cells will be a good alternative against the conventional energy sources in the near future, with their decreasing costs and increasing efficiencies. Photovoltaic cells (PV) are exposed to a lot of various loads depending on their increasing usage areas. Among the energy expenses for a building, the lighting system can contribute up to 50% of the total electrical consumption, and especially large quantities of energy are used in schools and office buildings. For that reason lighting devices are important energy consuming units in our daily life. In this study different load effects on PV cells are examined experimentally. D.C. and A.C. load behaviors are analyzed in switching and in steady state regime and their power-time curves are obtained for the demand of system power. Negative effects of the inverter circuit, which is used for feeding A.C. loads on the system, are expressed experimentally.
Functionally-Generalised MOQA Operations
Authors: Thierry Vallee
Venue: Electronic Notes in Theoretical Computer Science (ENTCS) (2009)

The programming language MOQA was designed by Michel Schellekens in [Schellekens M.: Compositional Average-Case Analysis, Preprint, submitted to the Journal of ACM (2006), 78p.; M.P. Schellekens, A Modular Calculus for the Average Cost of Data Structuring, Springer book to appear (2008), 250 pp.] specifically to facilitate the average execution time analysis of its programs. MOQA is based on a special data structure and an associated suite of operations. This special data structure, said here as labeled partial orders (lpo), is a pair (P,@?) such that P=(X,@?) is a poset and @?:X@?L a strictly increasing bijection between X and a totally ordered set L. MOQA basic operations are defined on lpo's under some restrictions. These restrictions guarantee the main property of MOQA's operations, said here as Automatic Random Preservation. Random Preservation (RP) is a fundamental property used to calculate the average time of programs, opening the way to a (semi-)automation of this calculation in MOQA. In the paper, we introduce functionally-generalised versions of some MOQA basic operations. Those versions are defined with more natural restrictions and in a more general way than the correspondent MOQA operations. As a consequence of their greater generality, they are not RP on all their domains in contrast to MOQA operations. Nevertheless, they have two good properties. The first one is that they have the intended semantics. For instance, the generalised split actually splits any lpo into two parts using a label as a pivot. The second one is that the subdomains on which they are RP are strictly bigger than the domains where MOQA basic operations are defined and RP. A tractable characterisation of those RP subdomains is an open problem and its solution would be an important step toward an implementation of the functionally-generalised operations as Automatic RP operations.
A Flexible Approach for Planning Schema Matching Algorithms
Authors: Fabien Duchateau, Zohra Bellahsene, Remi Coletta
Venue: Proceedings of the OTM 2008 Confederated International Conferences, CoopIS, DOA, GADA, IS, and ODBASE 2008. Part I on On the Move to Meaningful Internet Systems: (2008)

Most of the schema matching tools are assembled from multiple match algorithms, each employing a particular technique to improve matching accuracy and making matching systems extensible and customizable to a particular domain. The solutions provided by current schema matching tools consist in aggregating the results obtained by several match algorithms to improve the quality of the discovered matches. However, aggregation entails several drawbacks. Recently, it has been pointed out that the main issue is how to select the most suitable match algorithms to execute for a given domain and how to adjust the multiple knobs (e.g. threshold, performance, quality, etc.). In this article, we present a novel method for selecting the most appropriate schema matching algorithms. The matching engine makes use of a decision tree to combine the most appropriate match algorithms. As a first consequence of using the decision tree, the performance of the system is improved since the complexity is bounded by the height of the decision tree. Thus, only a subset of these match algorithms is used during the matching process. The second advantage is the improvement of the quality of matches. Indeed, for a given domain, only the most suitable match algorithms are used. The experiments show the effectiveness of our approach w.r.t. other matching tools.
On the predictive power of shortest-path weight inference
Authors: Andrew Coyle, Miro Kraetzl, Olaf Maennel, Matthew Roughan
Venue: Proceedings of the 8th ACM SIGCOMM conference on Internet measurement (2008)

Reverse engineering of the Internet is a valuable activity. Apart from providing scientific insight, the resulting datasets are invaluable in providing realistic network scenarios for other researchers. The Rocketfuel project attempted this process, but it is surprising how little effort has been made to validate its results. This paper concentrates on validating a particular inference methodology used to obtain link weights on a network. There is a basic difficulty in assessing the accuracy of such inferences in that a non-unique set of link-weights may produce the same routing, and so simple measurements of accuracy (even where ground truth data are available) do not capture the usefulness of a set of inferred weights. We propose a methodology based on predictive power to assess the quality of the weight inference. We used this to test Rocketfuel's algorithm, and our tests suggest that it is reasonably good particularly on certain topologies, though it has limitations when its underlying assumptions are incorrect.
Automated defect inspection of light-emitting diode chips using neural network and statistical approaches
Authors: Hong-Dar Lin
Venue: Expert Systems with Applications: An International Journal (2009)

This research explores the automated visual inspection of surface blemishes that fall across two different background textures in a light-emitting diode (LED) chip. Water-drop defects, commonly found on chip surface, impair the appearance of LEDs as well as their functionality and security. Automated inspection of a water-drop defect is difficult because the blemish has a semi-opaque appearance and a low intensity contrast with the rough exterior of the LED chip. Moreover, the blemish may fall across two different background textures, which further increases the difficulties of defect detection. The one-level Haar wavelet transform is used to decompose a chip image and extract four wavelet characteristics. Then, wavelet-based neural network (WNN) and wavelet-based multivariate statistical (WMS) approaches are proposed individually to integrate the multiple wavelet characteristics. Finally, the back-propagation algorithm of WNN and T^2 test of WMS individually judge the existence of water-drop defects. Experimental results show that both of the proposed methods achieve above 95% and 92% detection rates and below 7.5% and 5.8% false alarm rates, respectively.
A request-routing framework for SOA-based enterprise computing
Authors: Thomas Phan, Wen-Syan Li
Venue: Proceedings of the VLDB Endowment (2008)

Enterprises may use a service-oriented architecture (SOA) to provide a streamlined interface to their business processes. To scale up the system, each tier in a composite service usually deploys multiple servers for load distribution and fault tolerance. Such load distribution across multiple servers within the same tier can be viewed as horizontal load distribution. One limitation of this approach is that load cannot be further distributed when all servers in the same tier are fully loaded. In complex multi-tiered systems, a single business process may actually be implemented by multiple different computation pathways among the tiers, each with different components, in order to provide resiliency and scalability. Such SOA-based enterprise computing with multiple implementation options gives opportunities for vertical load distribution across tiers. In this paper, we propose a requestrouting framework for SOA-based enterprise computing that takes into consideration both horizontal and vertical load distribution. Through experimentation we show that our algorithm and methodology scale well up to a large system configuration comprising up to 1000 workflow requests to a complex composite service with multiple implementations. We also show that a combination of both horizontal and vertical load distributions gives the maximum flexibility to improve performance and fault tolerance.
Improving performance on mobile ad hoc networks by using proxy service
Authors: G. E. Rizos, D. C. Vasiliadis, E. Stergioy
Venue: WSEAS TRANSACTIONS on COMMUNICATIONS (2008)

In this paper, we present the role of proxy service in a MANET environment. MANET is specifically characterized by high mobility of network nodes and frequent changes of direct visibility. High dynamicity affects the design and implementation of distributed applications by significantly increasing their complexity, to consider not only routing and node configuration issues, but also the possible mobility of software components and the loss of direct connectivity during service provisioning. The proxy role is assigned dynamically in a completely decentralized way. Proxies exploit code mobility to install only when and where needed. In this work, we estimate and compare the performance of routing protocols for ad-hoc networks, namely Ad Hoc On-Demand Distance Vector protocol (AODV) and Dynamic Source Routing (DSR). We use the file transfer protocol to measure the performance of our model. The protocol provides file downloading from a dynamically discovered service component available in a MANET locality, even if the server moves during file transfer.
Access control over uncertain data
Authors: Vibhor Rastogi, Dan Suciu, Evan Welbourne
Venue: Proceedings of the VLDB Endowment (2008)

Access control is the problem of regulating access to secret information based on certain context information. In traditional applications, context information is known exactly, permitting a simple allow/deny semantics. In this paper, we look at access control when the context is itself uncertain. Our motivating application is RFID data management, in which the location of objects and people, and the associations between them is often uncertain to the system, yet access to private data is strictly defined in terms of these locations and associations. We formalize a natural semantics for access control that allows the release of partial information in the presence of uncertainty and describe an algorithm that uses a provably optimal perturbation function to enforce these semantics. To specify access control policies in practice, we describe UCAL, a new access control language for uncertain data. We then describe an output perturbation algorithm to implement access control policies described by UCAL. We carry out a set of experiments that demonstrate the feasibility of our approach and confirm its superiority over other possible approaches such as thresholding or sampling.