Slicing of Web Applications Using Source Code Analysis

Program slicing revealed a useful way to limit the search of software defects during debugging and to better understand the decomposition of the application into computations. The web application is very widely used for spreading business throughout the world. To meet the desire of the customers, web applications should have more quality and robustness. Slicing, in the ?eld of web application, helps disclosing relevant information and understanding the internal system structure. This in turn helps in debugging, testing and in improving the program comprehensibility. The system dependence graph is an appropriate data structure for slice computation, in that it explicitly represents all dependencies that have to be taken into account in slice determination. We have extended the system dependence graph to Web-Application Dependence Graph (WADG). We have developed a partial tool for automatic generation of the WADG and computation of slices. In our literature survey, we found that most of the automatic graph generation tools are byte-code based. But, our tool uses the dependency analysis from the source code of the given program. We have presented three case studies by taking open source web programs and applying our techniques and slicing algorithm. We have found that the slices computed is correct and precise, which will be help full for program debugging and testing. Construction of the system dependence graph for Web applications is complicated by the presence of dynamic code. In fact, a Web application builds the HTML code to be transmitted to the browser at run time. Knowledge of such code is essential for slicing

Vacuum and hover tests of a dihedral–anhedral tip composite rotor

This paper presents test data from vacuum and hover tests of a 2.8-ft-radius dihedral–anhedral tip composite rotor. The paper describes the blades, their fabrication, properties, instrumentation, the test conditions, and the data acquired. The blades were Mach-scaled to a generic but representative modern rotor. Vacuum chamber tests measured rotating frequencies and strains. Hover tests measured performance, blade loads, pitch-link loads, and strains under steady and cyclic loading conditions. Three-dimensional finite element structural models were developed to ensure completeness and consistency of property definition. The three-dimensional analysis was also used for a preliminary assessment of the test data. The test data revealed that the dihedral–anhedral tip influences the torsional and higher frequencies of a rotor blade significantly. The oscillatory blade loads show patterns consistent with the vertical center-of-gravity offset introduced by the tip. The surface strains reveal interesting higher-harmonic patterns of loading particularly near the dihedral junction

The Role of Xantphos in forming an Elusive dirhodium-η1-allyl Intermediate in a Rh(II)-Catalyzed Allylic Alkylation: A Combined Computational and Experimental Study

The use of dirhodium tetracarboxylate catalysts in multicomponent reactions involving allylic alkylation has been a formidable challenge to synthetic chemists. A unique strategy by means of catalyst structure modification in the presence of an external ligand, Xantphos, has recently enabled their efficient use in one-pot reactions involving carbene insertion into X–H bonds followed by allylic alkylation. However, the origin of the novel reactivity and the mechanism of such reactions remain unclear. Herein, we report a combined computational and experimental mechanistic study to shed light on the ligand-enabled catalyst structure modification and its implication in catalysis. This unique reactivity is enabled by the dissociation of an octanoate bridge driven by κ2-Xantphos ligation to the dirhodium core of the catalyst. This in turn allows for a hitherto unknown oxidative addition with the Rh(II) catalyst resulting in a dirhodium-η1-allyl species. For the first time, we confirm the presence of such a species in solution through in situ NMR and cyclic voltammetry experiments in line with DFT calculations. Alongside, we study the role of the base and solvent in generating the nucleophilic partner that can trap the electrophilic allylic species. This study is expected to guide future catalyst design, including chiral variants, for exploring newer modes of reactivity and selectivity using dirhodium catalysis