In this paper, we propose an algorithm for detecting deadlocks in a distributed Nested Transaction. This algorthms does not require that the global wait-for graph be built and maintained nor that the edges of a global wait-for graph be followed in order for deadlocks to be detected. Our algorithm uses the fact that transactions are organized in a tree structure. Each transaction maintains a representative wait-for graph that summarizes the waiting conditions in the subtree below the transaction. Deadlocks can be detected by individually checking these condensed wait-for graph.
Marta Rukoz received an under-graduate degree in Computer Science from the Central University of Venezuela in 1981, a Masters degree from Simon Bolivar University in 1985, and a Ph.D. from the Pierre et Marie Curie, Paris VI University in France. She was a member of the faculty at the Central University of Venezuela from 1982–1985 and returned in 1989 where she is currently a Professor Agregado. From 1987–1989 she worked at the University of Paris Nord. Professor Rukoz's research interests include: distributed algorithms, distributed databases, and Petri net models.A preliminary draft of this paper appears in Bermond J, Raynal M (eds) Proceedings of distributed algorithms. Lect Notes Comput Sci. vol. 392. Springer, Berlin Heidelberg New York, 1989 相似文献
Investigated the effects of deindividuating conditions (i.e., anonymity) on the behaviors and feelings of self-differentiated and less self-differentiated individuals. 40 male 17–18 yr olds were divided on the basis of their scores on the portable rod-and-frame test into self-differentiated and undifferentiated groups. Each S was exposed to transgressive and prosocial behavior of 2 group members who were confederates. Exposure to the models' behavior occurred under conditions of anonymity or identifiability. Additionally, measures of Ss' feelings were taken. Data indicate that relative to identifiability conditions, the transgressions and prosocial actions of the models had stronger effects on the behaviors of undifferentiated Ss under anonymity conditions. Also, undifferentiated Ss felt less self-conscious and less inhibited under anonymity than identifiability conditions. The behaviors and feelings of self-differentiated Ss were relatively unaffected by the anonymity–identifiability manipulation. A conceptual link between self-differentiation, self-awareness, and deindividuation is proposed. (22 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
In parametric design, changing values of parameters to get different solution instances to the problem at hand is a paramount operation. One of the main issues when generating the solution instance for the actual set of parameters is that the user does not know in general which is the set of parameter values for which the parametric solution is feasible. Similarly, in constraint-based dynamic geometry, knowing the set of critical points where construction feasibility changes would allow to avoid unexpected and unwanted behaviors.We consider parametric models in the Euclidean space with one internal degree of freedom. In this scenario, in general, the set of values of the variant parameter for which the parametric model is realizable and defines a valid shape is a set of intervals on the real line.In this work we report on our experiments implementing the van der Meiden Approach to compute the set of parameter values that bound intervals for which the parametric object is realizable. The implementation is developed on top of a constructive, ruler-and-compass geometric constraint solver. We formalize the underlying concepts and prove that our implementation is correct, that is, the approach exactly computes all the feasible interval bounds. 相似文献
Multimedia Tools and Applications - This work describes an end-to-end approach for real-time human action recognition from raw depth image-sequences. The proposal is based on a 3D fully... 相似文献
The most widely used technique to allow for parallel simulations in molecular dynamics is spatial domain decomposition, where the physical geometry is divided into boxes, one per processor. This technique can inherently produce computational load imbalance when either the spatial distribution of particles or the computational cost per particle is not uniform. This paper shows the benefits of using a hybrid MPI+OpenMP model to deal with this load imbalance. We consider LAMMPS (Large-scale Atomic/Molecular Massively Parallel Simulator), a prototypical molecular dynamics simulator that provides its own balancing mechanism and an OpenMP implementation for many of its modules, allowing for a hybrid setup. In this work, we extend the current OpenMP implementation of LAMMPS and optimize it and evaluate three different setups: MPI-only, MPI with the LAMMPS balance mechanism, and hybrid setup using our improved OpenMP version. This comparison is made using the five standard benchmarks included in the LAMMPS distribution plus two additional test cases. Results show that the hybrid approach can deal with load balancing problems better and more effectively (50% improvement versus MPI-only for a highly imbalanced test case) than the LAMMPS balance mechanism (only 43% improvement) and improve simulations with issues other than load imbalance.
With the advent of new cable and satellite services, and the next generation of digital TV systems, people are faced with an unprecedented level of program choice. This often means that viewers receive much more information than they can actually manage, which may lead them to believe that they are missing programs that could likely interest them. In this context, TV program recommendation systems allow us to cope with this problem by automatically matching user’s likes to TV programs and recommending the ones with higher user preference.This paper describes the design, development, and startup of queveo.tv: a Web 2.0 TV program recommendation system. The proposed hybrid approach (which combines content-filtering techniques with those based on collaborative filtering) also provides all typical advantages of any social network, such as supporting communication among users as well as allowing users to add and tag contents, rate and comment the items, etc. To eliminate the most serious limitations of collaborative filtering, we have resorted to a well-known matrix factorization technique in the implementation of the item-based collaborative filtering algorithm, which has shown a good behavior in the TV domain. Every step in the development of this application was taken keeping always in mind the main goal: to simplify as much as possible the user task of selecting what program to watch on TV. 相似文献
Statistical machine translation (SMT) is based on alignment models which learn from bilingual corpora the word correspondences
between source and target language. These models are assumed to be capable of learning reorderings. However, the difference
in word order between two languages is one of the most important sources of errors in SMT. In this paper, we show that SMT
can take advantage of inductive learning in order to solve reordering problems. Given a word alignment, we identify those
pairs of consecutive source blocks (sequences of words) whose translation is swapped, i.e. those blocks which, if swapped,
generate a correct monotonic translation. Afterwards, we classify these pairs into groups, following recursively a co-occurrence
block criterion, in order to infer reorderings. Inside the same group, we allow new internal combination in order to generalize
the reorder to unseen pairs of blocks. Then, we identify the pairs of blocks in the source corpora (both training and test)
which belong to the same group. We swap them and we use the modified source training corpora to realign and to build the final
translation system. We have evaluated our reordering approach both in alignment and translation quality. In addition, we have
used two state-of-the-art SMT systems: a Phrased-based and an Ngram-based. Experiments are reported on the EuroParl task,
showing improvements almost over 1 point in the standard MT evaluation metrics (mWER and BLEU). 相似文献
A method has been recently presented to predict the net primary production (NPP) of Mediterranean forests by integrating conventional and remote-sensing data. This method was based on the use of two models, C-Fix and BIOME-BGC, whose outputs are combined with estimates of stem volume and tree age to predict the NPP of the examined ecosystems. This article investigates the possibility of deriving these two forest attributes from airborne high-resolution lidar data. The research was carried out in the San Rossore pine forest, a test site in Central Italy where several investigations have been conducted. First, estimates of stand stem volume and tree age were obtained from lidar data by application of a simplified method based on existing literature and a few ground measurements. The accuracy of these stand attributes was assessed by comparison with the independent ground data derived from a recent forest inventory. Next, the stem volume and tree age estimates were used to drive the NPP modelling strategy, whose outputs were evaluated against the inventory measurements of current annual increment (CAI). The simplified lidar data processing method produces stand stem volume and tree age estimates having moderate accuracy, which are useful to feed the modelling strategy and predict CAI at a stand level. This method's success raises the possibility of integrating ecosystem modelling techniques and lidar data for the simulation of net forest carbon fluxes. 相似文献