Branch Path Research Articles

Automatic Classification of Program Paths Feasibility Using Active Learning

One of the challenging problems that faces the automated test data generation for path testing is the existence of infeasible paths, where no input data can be found to exercise them. Substantial time and effort may be wasted in trying to generate input data to exercise such paths. This paper proposes an active-learning approach to the automatic feasibility classification of program paths. This approach is based on the hypothesis that certain features of program behavior are stochastic processes that exhibit the Markov property, and that the resultant Markov models of individual program paths can be automatically clustered into effective predictors of path feasibility . To this end, the paper presents a technique that represents program paths as Markov models, and a clustering algorithm for Markov models that aggregates them into an effective path feasibility classifier. In this approach, the classifier is a map from program path statistics, namely, edge, branch, or definition-use profiles, to a label for the path, “feasible” or “infeasible”. The presented technique employs the bootstrapping active learning strategy, where the classifier is trained incrementally on a series of labeled instances, to extend its scope of training to be able to succeed in classifying new paths. The paper also presented the results of the experiments that were conducted to evaluate the effectiveness of the three paths feasibility classifiers built by using the proposed technique, and the bootstrapping technique.

A novel shortest path query algorithm

The shortest path query is one of the hot issues in graph research. In view of the low query efficiency and poor scalability caused by the long time of the construction of index and the large scale of index in the existing methods, we propose an associated index strategy based on the single branch path vertices, which is to construct the associated index for the vertex of single branch path vertices and construct the 2-hop label index for the other vertices in order to reduce the size and construction time of index by reducing the number of redundant data storage and graph traversal. Then we propose the corresponding shortest path query algorithm based on the single branch path vertices associated index. And then, we introduce the concept of core vertex for the construction of the 2-hop label index, which can further reduce the number of graph traversal and improve the efficiency of index construction. And we apply it to the shortest path query algorithm for the large graphs. Finally, according to test on the 12 real datasets, we verify the high efficiency of the method proposed in this paper compared with the existing methods from the following aspects, such as the index construction time, the index size and the shortest path query time.

Directed polymers on a disordered tree with a defect subtree

We study the question of how the competition between bulk disorder and a localized microscopic defect affects the macroscopic behavior of a system in the directed polymer context at the free energy level. We consider the directed polymer model on a disordered d-ary tree and represent the localized microscopic defect by modifying the disorder distribution at each vertex in a single path (branch), or in a subtree, of the tree. The polymer must choose between following the microscopic defect and finding the best branches through the bulk disorder. We describe three possible phases, called the fully pinned, partially pinned and depinned phases. When the microscopic defect is associated only with a single branch, we compute the free energy and the critical curve of the model, and show that the partially pinned phase does not occur. When the localized microscopic defect is associated with a non-disordered regular subtree of the disordered tree, the picture is more complicated. We prove that all three phases are non-empty below a critical temperature, and that the partially pinned phase disappears above the critical temperature.

Path generation algorithm for UML graphic modeling of aerospace test software

Aerospace traditional software testing engineers are based on their own work experience and communication with software development personnel to complete the description of the test software, manual writing test cases, time-consuming, inefficient, loopholes and more. Using the high reliability MBT tools developed by our company, the one-time modeling can automatically generate test case documents, which is efficient and accurate. UML model to describe the process accurately express the need to rely on the path is reached, the existing path generation algorithm are too simple, cannot be combined into a path and branch path with loop, or too cumbersome, too complicated arrangement generates a path is meaningless, for aerospace software testing is superfluous, I rely on our experience of ten load space, tailor developed a description of aerospace software UML graphics path generation algorithm.

Study of Virtual Nasopharyngeal Navigation Based on Virtual Endoscopy Technology

With the rapid development of medical imaging technology, computer graphics and visualization technologies, virtual endoscopy technology emerged. It mainly includes 2D medical image segmentation, 3D image reconstruction, path planning and virtual roaming. However, the path planning of virtual endoscopy has become one of the obstacles in this field due to the high irregularity of the nasopharyngeal anatomy structure. In this study, the nasopharynx including meatus nasi, pharyngeal canal, maxillary sinus, frontal sinus, sphenoid sinus, and ethmoid sinus is segmented and 3D reconstructed using MR images. The key technology of virtual endoscopy - center path planning algorithm is implemented based on distance transform. Also, two improved algorithms of center path planning are proposed. One is the selection algorithm of branch path and the other is the extraction algorithm for complex path based on human-computer interaction. These two improved algorithms can not only allow the traditional path planning algorithm to handle multiple branching structure but make roaming path to start at any point. Our experimental results satisfied the needs of clinical practice.

Determinacy in static analysis for jQuery

Static analysis for JavaScript can potentially help programmers find errors early during development. Although much progress has been made on analysis techniques, a major obstacle is the prevalence of libraries, in particular jQuery, which apply programming patterns that have detrimental consequences on the analysis precision and performance. Previous work on dynamic determinacy analysis has demonstrated how information about program expressions that always resolve to a fixed value in some call context may lead to significant scalability improvements of static analysis for such code. We present a static dataflow analysis for JavaScript that infers and exploits determinacy information on-the-fly, to enable analysis of some of the most complex parts of jQuery. The analysis combines selective context and path sensitivity, constant propagation, and branch pruning, based on a systematic investigation of the main causes of analysis imprecision when using a more basic analysis. The techniques are implemented in the TAJS analysis tool and evaluated on a collection of small programs that use jQuery. Our results show that the proposed analysis techniques boost both precision and performance, specifically for inferring type information and call graphs.

Type refinement for static analysis of JavaScript

Static analysis of JavaScript has proven useful for a variety of purposes, including optimization, error checking, security auditing, program refactoring, and more. We propose a technique called type refinement that can improve the precision of such static analyses for JavaScript without any discernible performance impact. Refinement is a known technique that uses the conditions in branch guards to refine the analysis information propagated along each branch path. The key insight of this paper is to recognize that JavaScript semantics include many implicit conditional checks on types, and that performing type refinement on these implicit checks provides significant benefit for analysis precision. To demonstrate the effectiveness of type refinement, we implement a static analysis tool for reporting potential type-errors in JavaScript programs. We provide an extensive empirical evaluation of type refinement using a benchmark suite containing a variety of JavaScript application domains, ranging from the standard performance benchmark suites (Sunspider and Octane), to open-source JavaScript applications, to machine-generated JavaScript via Emscripten. We show that type refinement can significantly improve analysis precision by up to 86% without affecting the performance of the analysis.

Using Load Method to Determine Bifurcation Point and Branch Path Based on FEM

Based on the basic principle of load disturbance method to implement equilibrium path transformation, this paper puts forward a new load method to deal with structural bifurcation point instability based on FEM. The unloading step obliterates the disturbance entirely, and the load method can get exact bifurcation point. The simple example demonstrates that the load method is practical and effective.

Modular Decomposition of Flow Chart Path Method and its Application

Modular decomposition is the key to simplify complex system. In this paper product function model is built based on flow chart description of energy, substance/material information. According to dependency relationship of function, function modularization is done respectively with module defining ways of main path method (MPM), branch path method (BPM) and conversion-conduction method (CCM). And modular decomposition of flow chart path method is established, concerned procedures and cautions during the implementing course are defined, and the purpose and effectiveness of modular decomposition of flow chart pass are confirmed through case analysis.

Effects of age-related increases in sapwood area, leaf area, and xylem conductivity on height-related hydraulic costs in two contrasting coniferous species

Knowledge of vertical variation in hydraulic parameters would improve our understanding of individual trunk functioning and likely have important implications for modeling water movement to the leaves. Specifically, understanding how foliage area (A l), sapwood area (A s), and hydraulic specific conductivity (k s) vary with canopy position to affect leaf-specific conductivity (LSC) and whole-tree leaf-specific hydraulic conductance (K l) may explain some of the contrasting patterns of A l/A s reported in the literature. The general aim of the study was to characterize and compare the aboveground relationships between cumulative A l, A s, and k s for two Pacific Northwest coniferous species with contrasting sapwood areas to give insight into size-related design of trees for water transport through changes in LSC and K l. The 230-year-old ponderosa pine (Pinus ponderosa) trees had slightly smaller basal diameters than the 102-year-old Douglas-fir (Pseudostuga menziesii) trees, but contained 85% sapwood at the base compared to 30% in Douglas-fir. At the tree base, there was no evidence that A l/A s decreased with tree age or with tree size. In both species, A l/A s of branches was significantly higher than A l/A s at the tree base, but it was not different from A l/A s measured in the trunks at the top of the tree. Douglas-fir had higher A l/A s at the base than did ponderosa pine (0.42 vs. 0.24 m2 cm−2), similar patterns of change in A l/A s with height, and similar values of k s, such that LSC in Douglas-fir was 77% the value of LSC in ponderosa pine. Compensating changes to increase LSC between short and tall trees occurred through an increased in k s in tall trees but not through a reduction in A l. LSC increased logarithmically with branch path length or trunk path length whereas K l decreased significantly from top to base of old trees, but not between sections from old and young trees of similar cambial age. Even though ponderosa pine had three times more sapwood than Douglas-fir, this study revealed a common relationship of declining K l with increasing tree height and diameter between the two species, within age classes and among trees. There was no compensating decrease in A l/A s as trees got taller, which showed that a homeostasis in K l was not maintained during growth. The trend of higher allocation of biomass to sapwood over leaves in ponderosa pine is consistent with this species’ tendency to inhabit drier sites than Douglas-fir.

Taxon ordering in phylogenetic trees by means of evolutionary algorithms.

BackgroundIn in a typical "left-to-right" phylogenetic tree, the vertical order of taxa is meaningless, as only the branch path between them reflects their degree of similarity. To make unresolved trees more informative, here we propose an innovative Evolutionary Algorithm (EA) method to search the best graphical representation of unresolved trees, in order to give a biological meaning to the vertical order of taxa.MethodsStarting from a West Nile virus phylogenetic tree, in a (1 + 1)-EA we evolved it by randomly rotating the internal nodes and selecting the tree with better fitness every generation. The fitness is a sum of genetic distances between the considered taxon and the r (radius) next taxa. After having set the radius to the best performance, we evolved the trees with (λ + μ)-EAs to study the influence of population on the algorithm.ResultsThe (1 + 1)-EA consistently outperformed a random search, and better results were obtained setting the radius to 8. The (λ + μ)-EAs performed as well as the (1 + 1), except the larger population (1000 + 1000).ConclusionsThe trees after the evolution showed an improvement both of the fitness (based on a genetic distance matrix, then close taxa are actually genetically close), and of the biological interpretation. Samples collected in the same state or year moved close each other, making the tree easier to interpret. Biological relationships between samples are also easier to observe.

An Efficient 4-D 8PSK TCM Decoder Architecture

This paper presents an efficient architecture for a 4-D eight-phase-shift-keying trellis-coded-modulation (TCM) decoder. First, a low-complexity architecture for the transition metric unit is proposed based on substructure sharing. This scheme significantly reduces the required computation without degrading the performance. Then, a new hybrid T -algorithm for a Viterbi decoder is developed by applying a T-algorithm on both branch metrics (BMs) and path metrics (PMs). TCM encoders usually employ high-rate convolutional codes that yield many more transition paths per state than low-rate codes do. This makes it feasible to purge unnecessary additions by applying the T -algorithm on BMs. Applying the T-algorithm on BMs instead of PMs allows one to move the ?search-for-the-optimal? operation out of the add-compare-select-unit (ACSU) loop. Hence, the clock speed will not be affected. In addition, by combining the T-algorithm on BMs and the T-algorithm on PMs, the hybrid T -algorithm can reduce the computations required with the conventional T-algorithm on PMs by as much as 50%.

Generalizing neural branch prediction

Improved branch prediction accuracy is essential to sustaining instruction throughput with today's deep pipelines. Traditional branch predictors exploit correlations between pattern history and branch outcome to predict branches, but there is a stronger and more natural correlation between path history and branch outcome. We explore the potential for exploiting this correlation. We introduce piecewise linear branch prediction , an idealized branch predictor that develops a set of linear functions, one for each program path to the branch to be predicted, that separate predicted taken from predicted not taken branches. Taken together, all of these linear functions form a piecewise linear decision surface. We present a limit study of this predictor showing its potential to greatly improve predictor accuracy. We then introduce a practical implementable branch predictor based on piecewise linear branch prediction. In making our predictor practical, we show how a parameterized version of it unifies the previously distinct concepts of perceptron prediction and path-based neural prediction. Our new branch predictor has implementation costs comparable to current prominent predictors in the literature while significantly improving accuracy. For a deeply pipelined simulated microarchitecture our predictor with a 256-KB hardware budget improves the harmonic mean normalized instructions-per-cycle rate by 8% over both the original path-based neural predictor and 2Bc- gskew . The average misprediction rate is decreased by 16% over the path-based neural predictor and by 22% over 2Bc- gskew .

A Comparative Computer Simulation of Dendritic Morphology

Computational modeling of neuronal morphology is a powerful tool for understanding developmental processes and structure-function relationships. We present a multifaceted approach based on stochastic sampling of morphological measures from digital reconstructions of real cells. We examined how dendritic elongation, branching, and taper are controlled by three morphometric determinants: Branch Order, Radius, and Path Distance from the soma. Virtual dendrites were simulated starting from 3,715 neuronal trees reconstructed in 16 different laboratories, including morphological classes as diverse as spinal motoneurons and dentate granule cells. Several emergent morphometrics were used to compare real and virtual trees. Relating model parameters to Branch Order best constrained the number of terminations for most morphological classes, except pyramidal cell apical trees, which were better described by a dependence on Path Distance. In contrast, bifurcation asymmetry was best constrained by Radius for apical, but Path Distance for basal trees. All determinants showed similar performance in capturing total surface area, while surface area asymmetry was best determined by Path Distance. Grouping by other characteristics, such as size, asymmetry, arborizations, or animal species, showed smaller differences than observed between apical and basal, pointing to the biological importance of this separation. Hybrid models using combinations of the determinants confirmed these trends and allowed a detailed characterization of morphological relations. The differential findings between morphological groups suggest different underlying developmental mechanisms. By comparing the effects of several morphometric determinants on the simulation of different neuronal classes, this approach sheds light on possible growth mechanism variations responsible for the observed neuronal diversity.

Weakest bus, most loaded transmission path and critical branch identification for voltage security reinforcement

Maximum power transmission and inadequate voltage control are the two main aspects associated with voltage security analysis. Once weak buses are found by the assessment function, enhancement control actions be may recommended. This paper presents a sequential iterative method to reinforce system conditions. A simple illustrative 34-bus system is used to show the adequacy and efficiency of the power flow reduction through the “critical branch” of the “most loaded transmission path”. Both concepts are introduced in this paper.

Quality-of-Service Mechanisms in All-IP Wireless Access Networks

In this paper, we focus on resource reservation protocol (RSVP)-based quality-of-service (QoS) provisioning schemes under Internet protocol (IP) micromobility. We consider QoS provisioning mechanisms for on-going RSVP flows during handoff. First, the rerouting of RSVP branch path at a crossover router (CR) at every handoff event can minimize resource reservation delays and signaling overheads, and in turn the handoff service degradation can be minimized. We show that RSVP branch path rerouting scheme could give a good tradeoff between the resource reservation cost and the link usage. Second, the new RSVP reservation can be made along the branch path toward the CR via a new base station in advance, while the existing reservation path is maintained, and in turn the on-going flow can be kept with the guaranteed QoS. We also show that seamless switching of RSVP branch path could provide the QoS guarantee by adaptively adjusting the pilot signal threshold values. Third, during RSVP resource reservation over wireless link, dynamic resource allocation scheme is used to give a statistical guarantee on the handoff success of on-going flows. We finally obtain the forced termination probability of guaranteed service flows, the average system time of best effort flows by using a transition rate matrix approach.

自律分散性を有する連動システムの提案 : 直線用・分岐用2種類のユニットからなるユニット連動システムの構成と安全性検証

自律分散性を有する連動システムの提案 : 直線用・分岐用2種類のユニットからなるユニット連動システムの構成と安全性検証

Reliable RSVP path reservation for multimedia communications under an IP micromobility scenario

We focus on how quality of service (QoS) guarantees can be provided for RSVP flows during handoff events in an IP micromobility network. For this purpose, RSVP message delays and signaling overheads should be minimized, and handoff service disruption should also be minimized. By rerouting the RSVP branch path at a crossover router at every handoff event, and establishing the new RSVP path between the CR and new BS in advance while the existing reservation path is maintained, ongoing RSVP flows can be kept with the guaranteed QoS. We propose the seamless switching of an RSVP branch path for soft handoff, and also show that this scheme could provide QoS guarantee with simulation and examples.

A statistical analysis of dendritic morphology's effect on neuron electrophysiology of CA3 pyramidal cells

Changes in CA3 pyramidal cell morphology have a significant effect on cell electrophysiology. Models of 16 pyramidal cells with uniform channel distribution were constructed from neuroanatomical data. Somatic injection of current produced distinct and different firing modes: spiking, bursting, and plateauing. Results show that the change in diameter as a function of the branch distance and path length from the soma is an indicator of firing behavior. Spike rate significantly correlated with dendritic length, surface area, bifurcations, terminations, and branch order. We conclude that dendritic morphology can significantly influence the qualitative and quantitative electrophysiological behavior of neurons.

A combined compiler and architecture technique to control multithreaded execution of branches and loop iterations

Simultaneous Speculation Scheduling ( S 3 ) is a combined compiler and architecture technique to control multiple path execution. It can be used for dual path branch speculation in case of unpredictable branches and for multiple path speculative execution of loop iterations in case of loop-carried dependences that make parallel execution otherwise impossible. We apply S 3 In situations where purely static techniques cannot prove data independence. S 3 can be seen as a cost-effective alternative to purely dynamic speculation techniques. We explain the S 3 technique and discuss the requirements on possible target architectures. We further compare S 3 to other speculation techniques.