ppxscal/embedding_network huggingface dataset:
Almost tight upper bounds for lower envelopes in higher dimensions
Authors: M. Sharir
Venue: Proceedings of the 1993 IEEE 34th Annual Foundations of Computer Science (1993)

We show that the combinatorial complexity of the lower envelope of n surfaces or surface patches in d-space (d/spl ges/3), all algebraic of constant maximum degree, and bounded by algebraic surfaces of constant maximum degree, is O(n/sup d-1+/spl epsi//), for any /spl epsi/>0; the constant of proportionality depends on /spl epsi/, d, and the shape and degree of the surface patches and of their boundaries. This is the first nontrivial general upper bound for this problem, and it almost establishes a long-standing conjecture that the complexity of the envelope is O(n/sup d-2//spl lambda//sub q/(n)) for some constant q depending on the shape and degree of the surfaces (where /spl lambda//sub q/(n) is the maximum length of (n,q) Davenport-Schinzel sequences). We also present a randomized algorithm for computing the envelope in three dimensions, with expected running time O(n/sup 2+/spl epsi//), and give several applications of the new bounds.
Location-aware routing protocol with dynamic adaptation of request zone for mobile ad hoc networks
Authors: Tzay-Farn Shih, Hsu-Chun Yen
Venue: Wireless Networks (2008)

One possibility direction to assist routing in Mobile Ad Hoc Network (MANET) is to use geographical location information provided by positioning devices such as global positioning systems (GPS). Instead of searching the route in the entire network blindly, position-based routing protocol uses the location information of mobile nodes to confine the route searching space into a smaller estimated range. The smaller route searching space to be searched, the less routing overhead and broadcast storm problem will occur. In this paper, we proposed a location-based routing protocol called LARDAR. There are three important characteristics be used in our protocol to improve the performance. Firstly, we use the location information of destination node to predict a smaller triangle or rectangle request zone that covers the position of destination in the past. The smaller route discovery space reduces the traffic of route request and the probability of collision. Secondly, in order to adapt the precision of the estimated request zone, and reduce the searching range, we applied a dynamic adaptation of request zone technique to trigger intermediate nodes using the location information of destination node to redefine a more precise request zone. Finally, an increasing-exclusive search approach is used to redo route discovery by a progressive increasing search angle basis when route discovery failed. This progressive increased request zone and exclusive search method is helpful to reduce routing overhead. It guarantees that the areas of route rediscovery will never exceed twice the entire network. Simulation results show that LARDAR has lower routing cost and collision than other protocols.
On the recognition of context-free languages using accepting hybrid networks of evolutionary processors
Authors: Florin Manea
Venue: International Journal of Computer Mathematics (2007)

In this paper we approach the problem of constructing an accepting device for the class of context-free languages, based on a newly defined computational model: Accepting Hybrid Network of Evolutionary Processors (AHNEPs). Although it is known that AHNEPs are Turing complete, and, consequently, for every context-free language, seen as a recursively enumerable language, we can construct an AHNEP that simulates the Turing machine accepting it, we choose a direct approach: the AHNEPs we design simulate the computation done by a non-deterministic push-down automata accepting the language. This approach leads to a more economic AHNEP since the number of processors we use depends linearly on the number of states and the number of working symbols of the automaton, while for the network obtained in the general case of recursively enumerable languages, the number of processors is linear in the number of states, but quadratic in the number of working symbols of a Turing machine accepting the given language. Finally, we particularize the AHNEP architecture we proposed in order to recognize regular languages. We obtain an upper bound for the number of processors needed close to that known for generating hybrid networks of evolutionary processors.
Bilateral Symmetry Detection for Real-time Robotics Applications
Authors: Wai Ho Li, Alan M. Zhang, Lindsay Kleeman
Venue: International Journal of Robotics Research (2008)

Bilateral symmetry is a salient visual feature of many man-made objects. In this paper, we present research that uses bilateral symmetry to identify, segment and track objects in real time using vision. Apart from the assumption of symmetry, the algorithms presented do not require any object models, such as color, shape or three-dimensional primitives. In order to counter the high computational cost of traditional symmetry detection methods, a novel computationally efficient algorithm is proposed. To investigate symmetry as an object feature, our fast detection scheme is applied to the tasks of object detection, segmentation and tracking. We find that objects with a line of symmetry can be segmented without relying on color or shape models by using a dynamic programming approach. Object tracking is achieved by estimating symmetry line parameters using a Kalman filter. The tracker operates at 40 frames per second on 640 x 480 video while running on a standard laptop PC. We use 10 difficult real-world tracking sequences to test our approach. We also quantitatively analyze symmetry as a tracking feature by comparing detected symmetry lines against ground truth. Color tracking is also performed to provide a qualitative comparison.
Mobilization by demonstration: using traces to re-author existing web sites
Authors: Jeffrey Nichols, Tessa Lau
Venue: Proceedings of the 13th international conference on Intelligent user interfaces (2008)

Today's web pages provide many useful features, but unfortunately nearly all are designed first and foremost for the desktop form factor. At the same time, the number of mobile devices with different form factors and unique input and output facilities is growing substantially. The Highlight re-authoring environment addresses these problems by allowing users to start with existing sites they already use and create mobile versions that are customized to their tasks and mobile devices. This "re-authoring" is performed through a combination of demonstrating desired interactions with an existing web site and directly specifying content to be included on mobile pages. The system has been tested successfully with a variety of existing sites. A study showed that novice users were able to use the system to create useful mobile applications for sites of their own choosing.
A handy imaging system for precision agriculture studies
Authors: Y. J. Lee, K. W. Chang, Y. Shen, T. M. Huang, H. L. Tsay
Venue: International Journal of Remote Sensing (2007)

An inexpensive imaging system able to take various narrow-band images and placed on platforms of various heights can be very useful to many remote-sensing studies, particularly for researchers in precision agriculture areas. A handy imaging system, composed of an Electrim EDC-1000L monochrome camera, a Canon PHF6 1.4 lens, a set of Andover bandpass filters, and an Advantech PCA6751 single board computer, was built up and installed with corresponding self-developed application software. The system had been deployed on platforms such as a mobile high-lift crane and helicopter to acquire various narrow-band images. This simplified imaging system may help greatly in performing validation tests on many stress-identification indices and related algorithms derived from ground spectroradiometer measurements.
Function approximation using artificial neural networks
Authors: Zarita Zainuddin, Ong Pauline
Venue: Proceedings of the 12th WSEAS International Conference on Applied Mathematics (2007)

Function approximation, which finds the underlying relationship from a given finite input-output data is the fundamental problem in a vast majority of real world applications, such as prediction, pattern recognition, data mining and classification. Various methods have been developed to address this problem, where one of them is by using artificial neural networks. In this paper, the radial basis function network and the wavelet neural network are applied in estimating periodic, exponential and piecewise continuous functions. Different types of basis functions are used as the activation function in the hidden nodes of the radial basis function network and the wavelet neural network. The performance is compared by using the normalized square root mean square error function as the indicator of the accuracy of these neural network models.
Rotating register allocation with multiple rotating branches
Authors: Suhyun Kim, Soo-Mook Moon
Venue: Proceedings of the 22nd annual international conference on Supercomputing (2008)

A rotating register file is an architectural support for software pipelining, where many registers can be renamed at once when a rotating branch is executed. It has primarily been used for overcoming the cross-iteration register overwrites in modulo-scheduled, straight-line or if-converted loops. Recently, a new technique has been proposed to use rotating registers for loops with arbitrary control flows, scheduled by enhanced pipeline scheduling (EPS). EPS generates many hard-to-delete copies to overcome the cross-iteration register overwrites, but these copies may cause a stall in addition to taking resources. The proposed technique eliminates those copies by allocating rotating registers, avoiding a serious slowdown caused by them. Unfortunately, it could not eliminate enough copies, as much as those removed by the unroll-based copy elimination technique, although both techniques employ the same abstraction called an extended live range (ELR). This is due to the limitation that only a branch edge can be a rotating branch, while any edge can be an unrolling edge. In this paper, we propose an enhanced rotating register allocation technique where we can use more than one rotating branches in order to eliminate more copies. This requires an extension of the theory of ELR and the rotating register allocation algorithm. Our experimental results indicate that our proposed technique can eliminate 20% more copies than the previous technique, which results in a performance improvement as much as more than 10%.
Safe open-nested transactions through ownership
Authors: Kunal Agrawal, I-Ting Angelina Lee, Jim Sukha
Venue: Proceedings of the twentieth annual symposium on Parallelism in algorithms and architectures (2008)

Researchers in transactional memory (TM) have proposed open-nested transactions for increasing concurrency. The idea is to ignore "low-level" memory operations of the open-nested transaction when detecting conflicts for its parent transaction, and instead perform abstract concurrency control for the "high-level" operation that nested transaction represents. Unfortunately, because the TM runtime is unaware of the different levels of memory, an unconstrained use of open-nested commits can lead to anomalous program behavior. We propose ownership-aware transactional memory (OATM) which explicitly incorporates the notion of modules into the TM system, and requires that transactions and data be associated with specific transactional modules or Xmodules. When a transaction in the OATM commits, the TM system uses this information about Xmodules and commits a piece of data differently depending on whether the current Xmodule owns the data or not. We call this commit mechanism ownership-aware commit, and it is a hybrid between an open-nested and closed-nested commit. Moreover, we give a set of precise constraints on interactions and sharing of data among the Xmodules based on familiar notions of abstractions. We prove that OATM has has clean memory-level semantics and can guarantee serializability by modules, which is an adaptation of multilevel serializability from databases to TM. Finally, we prove that if transactions in the process of aborting obey restrictions on their memory footprint, the OATM is free from semantic deadlock.
Enhancing the behavior of interior-point methods via identification of variables
Authors: María D. González-Lima
Venue: Optimization Methods Software (2007)

In many linear programming models of real life problems the solution set is not bounded. The presence of unbounded variables in the solution set can severely hurt the practical performance of primal-dual interior-point methods for linear programming that generate iterates which follow closely the central path or converge to the analytic center. In this work we study the effect of the unbounded variables by analysing the numerical behavior of the LSSN algorithm proposed by González-Lima, Tapia and Potra 1. when applied to linear problems with unbounded solution sets. We discuss the numerical behavior of the algorithm and we present a numerical procedure, based on the performance of the algorithm, to identify and remove the unbounded variables and related constraints. We develop theoretical support for the procedure and experimental evidence of its performance.
Towards patterns tree of gene coexpression in eukaryotic species
Authors: Haiyun Wang, Qi Wang, Xia Li, Bairong Shen, Min Ding, Ziyin Shen
Venue: Bioinformatics (2008)

Motivation: Cellular pathways behave coordinated regulation activity, and some reported works also have affirmed that genes in the same pathway have similar expression pattern. However, the complexity of biological systems regulation actually causes expression relationships between genes to display multiple patterns, such as linear, non-linear, local, global, linear with time-delayed, non-linear with time-delayed, monotonic and non-monotonic, which should be the explicit representation of cellular inner regulation mechanism in mRNA level. To investigate the relationship between different patterns, our work aims to systematically reveal gene-expression relationship patterns in cellular pathways and to check for the existence of dominating gene-expression pattern. By a large scale analysis of genes expression in three eukaryotic species, Saccharomyces cerevisiae, Caenorhabditis elegans and Human, we constructed gene coexpression patterns tree to systematically and hierarchically illustrate the different patterns and their interrelations. Results: The results show that the linear is the dominating expression pattern in the same pathway. The time-shifted pattern is another important relationship pattern. Many genes from the different pathway also present coexpression patterns. The non-linear, non-monotonic and time-delayed relationship patterns reflect the remote interactions between the genes in cellular processes. Gene coexpression phenomena in the same pathways are diverse in different species. Genes in S.cerevisiae and C.elegans present strong coexpression relationships, especially in C.elegans, coexpression is more universal and stronger due to its special array of genes. However in Human, gene coexpression is not apparent and the human genome involves more complicated functional relationships. In conclusion, different patterns corresponding to different coordinating behaviors coexist. The patterns trees of different species give us comprehensive insight and understanding of genes expression activity in the cellular society. Contact:whywhy_flying@163.com; wtq_flying@hotmail.com Supplementary information: Supplementary data are available at Bioinformatics online.
Atmospheric correction algorithm for MERIS above case-2 waters
Authors: Th. Schroeder, I. Behnert, M. Schaale, J. Fischer, R. Doerffer
Venue: International Journal of Remote Sensing (2007)

The development and validation of an atmospheric correction algorithm designed for the Medium Resolution Imaging Spectrometer (MERIS) with special emphasis on case-2 waters is described. The algorithm is based on inverse modelling of radiative transfer (RT) calculations using artificial neural network (ANN) techniques. The presented correction scheme is implemented as a direct inversion of spectral top-of-atmosphere (TOA) radiances into spectral remote sensing reflectances at the bottom-of-atmosphere (BOA), with additional output of the aerosol optical thickness (AOT) at four wavelengths for validation purposes. The inversion algorithm was applied to 13 MERIS Level1b data tracks of 2002-2003, covering the optically complex waters of the North and Baltic Sea region. A validation of the retrieved AOTs was performed with coincident in situ automatic sun-sky scanning radiometer measurements of the Aerosol Robotic Network (AERONET) from Helgoland Island located in the German Bight. The accuracy of the derived reflectances was validated with concurrent ship-borne reflectance measurements of the SIMBADA hand-held field radiometer. Compared to the MERIS Level2 standard reflectance product generated by the processor versions 3.55, 4.06 and 6.3, the results of the proposed algorithm show a significant improvement in accuracy, especially in the blue part of the spectrum, where the MERIS Level2 reflectances result in errors up to 122% compared to only 19% with the proposed algorithm. The overall mean errors within the spectral range of 412.5-708.75 nm are calculated to be 46.2% and 18.9% for the MERIS Level2 product and the presented algorithm, respectively.
A SVM-Based Change Detection Method from Bi-Temporal Remote Sensing Images in Forest Area
Authors: Dengkui Mo, Hui Lin, Jiping Li, Hua Sun, Zhuo Zhang, Yujiu Xiong
Venue: Proceedings of the First International Workshop on Knowledge Discovery and Data Mining (2008)

The reliability of support vector machines for classifying multi-spectral images of remote sensing has been proven in various studies. In this paper, we investigate their applicability for land cover change detection in forest regions. Firstly, multidate remote sensing images are co-registered and we have stacked the NDVI index layers of two dates in red, green, blue bands composite to perform a supervised classification. Secondly, sample pixels were manually selected from changed and unchanged area to be used in the training stage. Thirdly, for each pixel SVM produces a single output through its decision function, high detection overall accuracy (>96%) and overall Kappa coefficient (>0.89) were achieved using two Landsat images covering an 8-years period in study area. Lastly, SVM-based change detection with different kernel functions was compared using statistical evaluations. Keywords: change detection, support vector machines, classification, forest, remote sensing.
GUARANTEED COST CONTROL FOR A CLASS OF UNCERTAIN SWITCHED DELAY SYSTEMS: AN AVERAGE DWELL-TIME METHOD
Authors: Rui Wang, Jun Zhao
Venue: Cybernetics and Systems (2007)

This paper deals with the problem of guaranteed cost robust control for a class of uncertain switched delay systems composed of controllable and uncontrollable subsystems. By making use of the scheme of average dwell time and under the condition that the activation time ratio between controllable subsystems and uncontrollable ones is not less than a specified constant, the state feedback controllers are derived in terms of linear matrix inequalities (LMIs) such that the resulting closed-loop system is exponentially stable for all admissible uncertainties and has a weighted guaranteed cost upper bound. As an example, the controller design for an AV-8A Harrier VTOL aircraft illustrates the effectiveness of the proposed approach.
IMS Application Servers: Roles, Requirements, and Implementation Technologies
Authors: Hechmi Khlifi, Jean-Charles Grégoire
Venue: IEEE Internet Computing (2008)

The IP multimedia subsystem (IMS) defines a generic architecture to support communication services over a Session Initiation Protocol (SIP) infrastructure. In the IMS architecture, application servers host and execute the IMS service logic. These servers can be SIP application servers, open services architecture (OSA) application servers, or a customized applications for mobile networks using enhanced logic (Camel) service environment. Some technologies used in telephony and voice-over-IP (VoIP) application servers are also applicable to IMS application servers, but such servers have some unique requirements that could limit the extent to which these technologies can meet them.
Simulation Applications Based on Digital Terrain Models Integrated in Web3D Viewers and Graphic Engines
Authors: F. Sanz Adán, E. Jiménez Macías, E. Martínez Cámara, M. Pérez de la Parte
Venue: Proceedings of the Tenth International Conference on Computer Modeling and Simulation (2008)

Digital terrain models constitute the base of terrain visualization applications, used to visualize in an easy and powerful way a great quantity of information obtained from the terrain, such as occurs in virtual terrain visualization systems, used to know and enjoy land, training simulations, determination of visual impacts, etc. But these models can also be used as the base for other applications that simulate events concerning the terrain, in other to estimate their effects, such us development of roads, mines, dams, and general building works, establishment of water behaviour in rivers or dams, real military strategy simulation, simulation of natural phenomena such as floods, volcanic eruptions, landslides and avalanches, etc.This work shows the steps and methodology followed to develop a virtual terrain visualization application, based on Web3D viewers and graphic engines, as well as the simulation applications developed in both cases in order to simulate effects and optimise actuations.
Assigning game server roles in mobile ad-hoc networks
Authors: Oliver Wellnitz, Lars Wolf
Venue: Proceedings of the 2006 international workshop on Network and operating systems support for digital audio and video (2006)

Over the last couple of years, multi-player games have become more and more popular. Additionally, new mobile devices now have sufficient resources to play these multi-player games in mobile and wireless networks. As the classic centralised game server design is unsuited for mobile ad-hoc networks, a group of nodes can take the role of a distributed game server. This group of nodes can provide the necessary redundancy which is needed in the dynamic environment of a mobile ad-hoc network. In this paper we present a modified dominating set algorithm for server selection which uses local information to determine well-suited nodes from the group of players. Our algorithm uses three phases (discovery, determination and marking) to calculate an initial server set and adjusts to network changes during the game. We implemented our server selection algorithm in NS-2 and evaluated its behaviour in two different realistic scenarios for mobile games (schoolyard and train) as well as in an artificial stress scenario.
Simplifying the Dualized Threading Model of RTSJ
Authors: Pablo Basanta-Val, Marisol García-Valls, Iria Estévez-Ayres
Venue: Proceedings of the 2008 11th IEEE Symposium on Object Oriented Real-Time Distributed Computing (2008)

Current RTSJ (The Real-Time Specification for Java) threading model is dualized: programmers have to decide between the high predictability offered by its region-based model and the flexibility offered by its garbage-collected model. Up to now, there is not a unique type of thread that offers, in a single entity, the highest predictability, and flexibility together. This lack has serious consequences on the programmer who has to deal with new and sometimes non-trivial mechanisms, such as queues of objects or the No-heap Real-Time Threads, to avoid the priority inversion caused by the garbage collector. In order to tackle these issues and provide an improved and more generalized programming model, the authors propose an extension to the current threading model that unifies the RTSJ threading model: the RealtimeThread++ extension.