ppxscal/embedding_network huggingface dataset:
Stagewise Lasso
Authors: Peng Zhao, Bin Yu
Venue: The Journal of Machine Learning Research (2007)

Many statistical machine learning algorithms minimize either an empirical loss function as in AdaBoost, or a penalized empirical loss as in Lasso or SVM. A single regularization tuning parameter controls the trade-off between fidelity to the data and generalizability, or equivalently between bias and variance. When this tuning parameter changes, a regularization "path" of solutions to the minimization problem is generated, and the whole path is needed to select a tuning parameter to optimize the prediction or interpretation performance. Algorithms such as homotopy-Lasso or LARS-Lasso and Forward Stagewise Fitting (FSF) (aka e-Boosting) are of great interest because of their resulted sparse models for interpretation in addition to prediction. In this paper, we propose the BLasso algorithm that ties the FSF (e-Boosting) algorithm with the Lasso method that minimizes the L1 penalized L2 loss. BLasso is derived as a coordinate descent method with a fixed stepsize applied to the general Lasso loss function (L1 penalized convex loss). It consists of both a forward step and a backward step. The forward step is similar to e-Boosting or FSF, but the backward step is new and revises the FSF (or e-Boosting) path to approximate the Lasso path. In the cases of a finite number of base learners and a bounded Hessian of the loss function, the BLasso path is shown to converge to the Lasso path when the stepsize goes to zero. For cases with a larger number of base learners than the sample size and when the true model is sparse, our simulations indicate that the BLasso model estimates are sparser than those from FSF with comparable or slightly better prediction performance, and that the the discrete stepsize of BLasso and FSF has an additional regularization effect in terms of prediction and sparsity. Moreover, we introduce the Generalized BLasso algorithm to minimize a general convex loss penalized by a general convex function. Since the (Generalized) BLasso relies only on differences not derivatives, we conclude that it provides a class of simple and easy-to-implement algorithms for tracing the regularization or solution paths of penalized minimization problems.
Comparative use of processed satellite images in remote sensing of mass movements: Lebanon as a case study
Authors: C. Abdallah, J. Chorowicz, R. Boukheir, D. Dhont
Venue: International Journal of Remote Sensing (2007)

Mass movements (MM) represent a serious threat to human life and activities in most mountainous areas. However, due to the rugged nature of such terrain, it is often difficult to detect such phenomena in remote areas. Hence, satellite imagery offers many attractions for the examination of MM in such environments, especially in less developed nations in which resources are stretched and levels of environmental information limited. There is a need to ensure that the techniques and images used are effective, reliable, and cheap in terms of the amount and accuracy of data that can be extracted. Taking Lebanon as a case study, this paper compares the applicability of different satellite data sensors (Landsat TM (Thematic Mapper), IRS (Indian Remote Sensing Satellite), SPOT4 (Système Probatoire pour l'Observation de la Terre)) and preferred image-processing techniques (False Colour Composite 'FCC', pan-sharpen, principal-component analysis 'PCA', Anaglyph) for the mapping of MM recognized as landslides, rock and debris falls, and earth flows. Results from the imagery have been validated by field surveys and analysis of IKONOS imagery acquired in some locations witnessing major MM during long periods. Then, levels of accuracies of detected MM from satellite imageries were plotted. This study has demonstrated that the anaglyph produced from the two panchromatic stereo-pairs SPOT4 images remains the most effective tool setting the needed 3D properties for visual interpretation and showing a maximum accuracy level of 67%. The PCA pan-sharpened Landsat TM-IRS image gave better results in detecting MM, among other processing techniques, with a maximum accuracy level of 62%.
Time-Related Replication for P2P Storage System
Authors: Kyungbaek Kim
Venue: Proceedings of the Seventh International Conference on Networking (2008)

Many p2p based wide-area storage systems are appeared to provide scalable storage services with idle resource from many unreliable clients. To minimize the data loss, quick replication is important to replace lost redundancy on other nodes in reaction to failures. The popular approach is the availability based replication which uses the individual node availability. However, with the high churn some replicas leave or fail within similar time. As a result, it requires bursty data traffic and sometimes it loses data. This paper explores the time-related replication which uses the information of the session time to prevent the bursty failures. It tries to get the primary replica which has enough time to replace the lost redundancy. Moreover, the sparse replicas spread on the timeline and the number of overlapped replicas lessens as best it can. Results from a simulation study suggest that the time-related replication keep the high data availability with less data copy traffic.
Finding a longest common subsequence between a run-length-encoded string and an uncompressed string
Authors: J. J. Liu, Y. L. Wang, R. C. T. Lee
Venue: Journal of Complexity (2008)

In this paper, we propose an O(min{mN,Mn}) time algorithm for finding a longest common subsequence of strings X and Y with lengths M and N, respectively, and run-length-encoded lengths m and n, respectively. We propose a new recursive formula for finding a longest common subsequence of Y and X which is in the run-length-encoded format. That is, Y=y"1y"2...y"N and X=r"1^l^"^1r"2^l^"^2...r"m^l^"^m, where r"i is the repeated character of run i and l"i is the number of its repetitions. There are three cases in the proposed recursive formula in which two cases are for r"i matching y"j. The third case is for r"i mismatching y"j. We will look specifically at the prior two cases that r"i matches y"j. To determine which case will be used when r"i matches y"j, we have to find a specific value which can be obtained by using another of our proposed recursive formulas.
A Semi-automatic Extraction Algorithm of Lung Lobar Fissures from HRCT Images Using Ridgelet
Authors: Guodong Zhang, Xin Zhang, Hong Zhao, Peiyu Yan
Venue: Proceedings of the 2008 International Conference on BioMedical Engineering and Informatics - Volume 01 (2008)

The pulmonary fissures are the boundaries between the lobes in the lungs. They are useful for the analysis of pulmonary conformation and the diagnosis of lung disease on a lobar level. This paper introduces a technique for the semi-automatic extraction of lung lobar major fissures on HRCT images. First we get the direction and approximate bound of the fissure using Ridgelet transform, and then use converging area method to locate the fissure area. After that, a method based on gradient operator is used to extract the fissure. At last, we can get a continuous fissure using polynomial fit. We applied the proposed algorithm to 200 HRCT images. The average distance between the results of this algorithm and the manually delineated fissures is less than 1.5 mm, within the range of manual extraction variations. The extracted fissures will be aided to diagnose lung cancer and to assess pulmonary emphysema quantified on lobar level automatically.
A heuristic dynamic programming algorithm for 2D unconstrained guillotine cutting
Authors: Xiang Song, Cheng-Bin Chu, Yi-Yong Nie
Venue: Proceedings of the 5th WSEAS International Conference on Applied Mathematics (2004)

In this paper, a heuristic dynamic-programming recursion is proposed for solving unconstrained 2D knapsack problem efficiently. The algorithm we propose is an incompletely enumerative method, in which some intricate cutting patterns may not be enumerated. Compared with the traditional dynamic-programming, the algorithm gives a high percentage of optimal solutions (93%) with a much lower computational complexity. Some theoretical analyses for the algorithm are performed. Computational results are given for small and medium-sized problems.
A stochastic foundation of available bandwidth estimation: multi-hop analysis
Authors: Xiliang Liu, Kaliappa Ravindran, Dmitri Loguinov
Venue: IEEE/ACM Transactions on Networking (TON) (2008)

This paper analyzes the asymptotic behavior of packet-train probing over a multi-hop network path P carrying arbitrarily routed bursty cross-traffic flows. We examine the statistical mean of the packet-train output dispersions and its relationship to the input dispersion. We call this relationship the response curve of path P. We show that the real response curve Z is tightly lower-bounded by its multi-hop fluid counterpart F, obtained when every cross-traffic flow on P is hypothetically replaced with a constant-rate fluid flow of the same average intensity and routing pattern. The real curve Z asymptotically approaches its fluid counterpart F as probing packet size or packet train length increases. Most existing measurement techniques are based upon the single-hop fluid curve S associated with the bottleneck link in P. We note that the curve S coincides with F in a certain large-dispersion input range, but falls below F in the remaining small-dispersion input ranges. As an implication of these findings, we show that bursty cross-traffic in multi-hop paths causes negative bias (asymptotic underestimation) to most existing techniques. This bias can be mitigated by reducing the deviation of Z from S using large packet size or long packet-trains. However, the bias is not completely removable for the techniques that use the portion of Sthat falls below F.
Exploiting sink movement for energy-efficient load-balancing in wireless sensor networks
Authors: Gaotao Shi, Minghong Liao, Maode Ma, Yantai Shu
Venue: Proceeding of the 1st ACM international workshop on Foundations of wireless ad hoc and sensor networking and computing (2008)

Prolonging the lifetime is an important design consideration for battery powered wireless sensor networks. In a network with stationary sink, the sensor nodes located near the sink have to relay data from the rest of the network and thus deplete their energy very quickly. A sink mobility strategy was proposed in [1], which manages the sink to move along the periphery of the network for load-balancing. In this paper, based on the work in [1], we study the relationship of the energy efficiency and load-balancing. A novel mobility scheme for sink has been proposed to achieve the energy efficient load-balancing. By this scheme, the sink is controlled to move along a circle trajectory in a stationary for data buffering. All sensed data are forwarded into the annularity area firstly and then collected by the mobile sink. We find the optimum trajectory of sink movement with consideration of energy consumption and load-balancing and present how to find the location for the buffering area. Compared with the static sink scheme and the existing mobile sink scheme, the proposed is the most energy-efficient and it can reduce the load by 95% and 70%, respectively.
Computing all the best swap edges distributively
Authors: P. Flocchini, L. Pagli, G. Prencipe, N. Santoro, P. Widmayer
Venue: Journal of Parallel and Distributed Computing (2008)

Recently great attention has been given to point-of-failure swap rerouting, an efficient technique for routing in the presence of transient failures. According to this technique, a message follows the normal routing table information unless the next hop has failed; in this case, it is redirected towards a precomputed link, called swap; once this link has been crossed, normal routing is resumed. The choice of the swap edge is done according to some optimization criteria on the resulting new route. The amount of precomputed information required in addition to the routing table is rather small: a single link per each destination. Several efficient serial algorithms have been presented to compute this information for several optimization criteria (F"d"i"s"t, F"s"u"m, F"i"n"c"r, F"m"a"x). Only the algorithm corresponding to F"d"i"s"t has been efficiently implemented in a distributed environment, while for the other optimization criteria no distributed solution has been devised yet. In this paper we present protocols, based on a new strategy, that allow the efficient distributed computation of all the optimal swap edges under F"s"u"m, F"i"n"c"r, F"m"a"x. Although considerably more difficult than F"d"i"s"t, these problems can be solved with the same cost. In systems allowing long messages, we develop solution protocols based on the same strategy that use only O(n) messages without increasing the total amount of transmitted data items.
Soft error vulnerability of iterative linear algebra methods
Authors: Greg Bronevetsky, Bronis de Supinski
Venue: Proceedings of the 22nd annual international conference on Supercomputing (2008)

Devices are increasingly vulnerable to soft errors as their feature sizes shrink. Previously, soft error rates were significant primarily in space and high-atmospheric computing. Modern architectures now use features so small at sufficiently low voltages that soft errors are becoming important even at terrestrial altitudes. Due to their large number of components, supercomputers are particularly susceptible to soft errors. Since many large scale parallel scientific applications use iterative linear algebra methods, the soft error vulnerability of these methods constitutes a large fraction of the applications' overall vulnerability. Many users consider these methods invulnerable to most soft errors since they converge from an imprecise solution to a precise one. However, we show in this paper that iterative methods are vulnerable to soft errors, exhibiting both silent data corruptions and poor ability to detect errors. Further, we evaluate a variety of soft error detection and tolerance techniques, including checkpointing, linear matrix encodings, and residual tracking techniques.
Spectral Information Recovery for Compressed Image Restoration
Authors: Jingjing Fu, Feng Wu, Bing Zeng
Venue: Proceedings of the Data Compression Conference (2008)

The restoration of compressed images typically focuses on the removing of spatial artifacts caused by quantization error rather than the recovery of spectral information in compressed images. In this paper, we attempt to solve the compressed image restoration by considering the recovery of spectral information in compressed images. To this end, we convert this recovery problem to a route searching process in the high dimensional vector space spanned by all DCT coefficients. Since there are huge number of routes in the search space, we present two crucial issues in route construction: how to decide the nodes along the searching route and how to restrict the route within a reasonable sub-space. Total variation (TV) based regularization is applied to determine all the nodes in the searching process, and two constraints on the DCT coefficients are proposed to prune the searching space. Experimental results of our algorithm show a remarkable improvement in both PSNR and visual quality.
Statistical modeling and simulation of threshold variation under dopant fluctuations and line-edge roughness
Authors: Yun Ye, Frank Liu, Sani Nassif, Yu Cao
Venue: Proceedings of the 45th annual Design Automation Conference (2008)

The threshold voltage (Vth) of a nanoscale transistor is severely affected by random dopant fluctuations and line-edge roughness. The analysis of these effects usually requires atomistic simulations that are too expensive computationally for statistical circuit design. In this work, we develop an efficient SPICE simulation method and statistical transistor model that accurately predict threshold variation as a function of dopant fluctuations and gate length change caused by sub-wavelength lithography and gate etching process. By understanding the physical principles of atomistic simulations, we (a) identify the appropriate method to divide a non-uniform gate into slices in order to map those fluctuations into the device model; (b) extract the variation of Vth from the strong-inversion region instead of the leakage current, benefiting from the linearity of the saturation current with respect to Vth and (c) propose a compact model of Vth variation that is scalable with gate size and the amount of dopant and gate length fluctuations. The proposed SPICE simulation method is fully validated against atomistic simulation results. Given the post-lithography gate geometry, this approach correctly models the variation of device output current in all operating regions. Based on the new results, we further project the amount of Vth variation at advanced technology nodes, to help shed light on the challenges of future robust circuit design.
Review of "The Definitive Guide to the Xen Hypervisor" (Prentice Hall Open Source Software Development Series) David Chisnall, Prentice Hall PTR, 2007, $49.99, ISBN: 013234971X
Authors: Harry J. Foxwell
Venue: Queue (2008)

The Definitive Guide to the Xen Hypervisor (Prentice Hall Open Source Software Development Series) David Chisnall, Prentice Hall PTR, 2007, $49.99, ISBN: 013234971X.
An Extended Concurrency Control Service for CORBA
Authors: Nima Sharifimehr, Samira Sadaoui
Venue: Proceedings of the 19th Australian Conference on Software Engineering (2008)

Distributed transaction processing is the best solution for providing enterprise software systems with high performance. However, it needs an environment that assures consistency beside high concurrency. Therefore in this paper we extend the Concurrency Control Service (CCS) of CORBA with new features, such as generic calling context, fault tolerance and deadlock management. The most outstanding feature of ECCS is the generic calling context that makes it applicable for both transactional and non-transactional clients. Through fault tolerance considerations, ECCS supports long-duration distributed transactions in addition to short-duration ones. Deadlock management efficiently prevents any deadlock occurrences. The experimentations show that we successfully included all the new capabilities with an acceptable amount of overhead and without negatively affecting the scalability of CCS.
Understanding human-battery interaction on mobile phones
Authors: Ahmad Rahmati, Angela Qian, Lin Zhong
Venue: Proceedings of the 9th international conference on Human computer interaction with mobile devices and services (2007)

Mobile phone users have to deal with limited battery lifetime through a reciprocal process we call human-battery interaction (HBI). We conducted three user studies in order to understand HBI and discover the problems in existing mobile phone designs. The studies include a large-scale international survey, a one-month field data collection including quantitative battery logging and qualitative inquiries from ten mobile phone users, and structured interviews with twenty additional mobile phone users. We evaluated various aspects of HBI, including charging behavior, battery indicators, user interfaces for power-saving settings, user knowledge, and user reaction. We find that mobile phone users can be categorized into two types regarding HBI and often have inadequate knowledge regarding phone power characteristics. We provide qualitative and quantitative evidence that problems in state-of-the-art user interfaces has led to under-utilized power-saving settings, under-utilized battery energy, and dissatisfied users. Our findings provide insights into improving mobile phone design for users to effectively deal with the limited battery lifetime. Our work is the first to systematically address HBI on mobile phones and is complementary to the extensive research on energy-efficient design for a longer battery lifetime.
Location Information Look-Up for Intelligent Handover Decision
Authors: Soohong Park, Minho Lee, Cheolju Hwang
Venue: Proceedings of the 22nd International Conference on Advanced Information Networking and Applications - Workshops (2008)

IEEE 802.21 standard is developing media independent handover service which is consist of three services, Media Independent Command Service, Media Independent Event Service, and Media Independent Information Service. Media Independent Information Service provides a framework by which a Media Independent Handover Function both in a mobile node and in a network can discover and obtain homogeneous and heterogeneous network information within a geographical area to facilitate handovers. Also, Media Independent Information Service includes support for various Information Elements providing information that is essential for a handover module in the mobile node to make intelligent handover decision stored in Information Server. To do so, the mobile node has to discover at least one available Information Server in networks. This paper proposes a new mechanism in conjunction with DHCP to discover various network information stored somewhere in Internet. Also, implementation has shown that the proposed mechanism can be a convenient and valuable IS location information discovery mechanism in some cases.
Heuristic Algorithms for Replication Transition Problem in the Grid Systems
Authors: Chun-Chen Hsu, Pangfeng Liu, Chien-Min Wang
Venue: Proceedings of the 2008 Eighth IEEE International Symposium on Cluster Computing and the Grid (2008)

We study the replication transition problem (RTP) in the Grid systems. Most distributed systems replicate data to increase data access efficiency. A replication strategy dictates where the replicas arestored in respond to data access pattern, and a good strategy can improve data access efficiency. However, the access patternin a distributed system is constantly changing. As a result a good replication strategy must evolve accordingly. The replication transition problem is to seek an efficient transition from one replication strategy to another in order to cope with the dynamic data access pattern. This paper focuses on the RTP problem for Grid systems in four communication models that have different communication capabilities, i.e., whether message forwarding is allowed and whether network capacity is uniform among different links. We show that there exists a polynomial time algorithm that provides optimal solution for the RTP problem when forwarding is not allowed and the communication links are uniform. We also propose heuristic algorithms for solving variants of the RTP problem and conduct experiments to evaluate their performances. The experimental results indicate that our proposed heuristics are very effective.
An Autonomous Algorithm for Construction of Energy-conscious Communication Tree in Wireless Sensor Networks
Authors: Katsumi Onodera, Toshiaki Miyazaki
Venue: Proceedings of the 22nd International Conference on Advanced Information Networking and Applications - Workshops (2008)

In wireless sensor networks, it is useful to construct a tree communication network topology in order to effectively collect sensed data from sensor nodes at a sink node. In the tree, the sink node should be a root node, and all the data sensed in the sensor nodes are transferred to the sink node using the tree connections. Compared to other topologies such as the mesh and random topologies, the tree topology does not request any routing protocols because each route from a sensor node to the sink node is uniquely decided after the tree structure is constructed. In this paper, we propose an autonomous algorithm for tree creation and its maintenance. It can extend the lifetime of the sensor network and support efficient data aggregation by balancing the communication tree structure automatically. Moreover, our algorithm simply manages all the involved sensor nodes and creates a tree structure by using them. Thus, this algorithm can be applied to actual sensor networks along with other algorithms or protocols. After describing the algorithm, some experimental results are shown to prove its effectiveness and robustness.