The Stratosphere platform for big data analytics

We present Stratosphere, an open-source software stack for parallel data analysis. Stratosphere brings together a unique set of features that allow the expressive, easy, and efficient programming of analytical applications at very large scale. Stratosphere’s features include “in situ” data processing, a declarative query language, treatment of user-defined functions as first-class citizens, automatic program parallelization and optimization, support for iterative programs, and a scalable and efficient execution engine. Stratosphere covers a variety of “Big Data” use cases, such as data warehousing, information extraction and integration, data cleansing, graph analysis, and statistical analysis applications. In this paper, we present the overall system architecture design decisions, introduce Stratosphere through example queries, and then dive into the internal workings of the system’s components that relate to extensibility, programming model, optimization, and query execution. We experimentally compare Stratosphere against popular open-source alternatives, and we conclude with a research outlook for the next years.     

A hybrid swarm intelligence algorithm for the travelling salesman problem

Abstract: We present a hybrid model named HRKPG that combines the random‐key search method and an individual enhancement scheme to thoroughly exploit the global search ability of particle swarm optimization. With a genetic algorithm, we can expand the area of exploration of individuals in the solution space. With the individual enhancement scheme, we can enhance the particle swarm optimization and the genetic algorithm for the travelling salesman problem. The objective of the travelling salesman problem is to find the shortest route that starts from a city, visits every city once, and finally comes back to the start city. With the random‐key search method, we can search the ability of the particle and chromosome. On the basis of the proposed hybrid scheme of HRKPG, we can improve solution quality quite a lot. Our experimental results show that the HRKPG model outperforms the particle swarm optimization and genetic algorithm in solution quality.     

Exact solutions of the cubic–quintic Swift–Hohenberg equation and their bifurcations

Many systems of physical interest may be modelled by the bistable Swift–Hohenberg equation with cubic–quintic nonlinearity. We construct a two-parameter family of exact meromorphic solutions of the time-independent equation and use these to construct a one-parameter family of exact periodic solutions on the real line. These are of two types, differing in their symmetry properties, and are connected via an exact heteroclinic solution. We use these exact solutions as initial points for numerical continuation and show that some of these lie on secondary branches while others fall on isolas. The approach substantially enhances our understanding of the solution space of this equation.     

Using a new strategy to optimize the bump design parameters in flip chip packages

Flip chip technology has rapidly progressed in concert with the high speed and small dimension trends in electronic devices. The bump interconnects design dominates the performance of a flip chip package. This study produced a new strategy to optimize the geometric design parameters of the bump from the electrical standpoint. The first incident voltage was employed as the optimization objective function in order to reduce the response time delay in the binary command as well as maintain the chip level efficiency. Genetic algorithms were used for the search routines to evaluate the best bump geometric solutions. Two cases, 1.5 v V and 3.3 v V power supply voltage, were adopted to conduct this research in both air and underfill environments. The results show that the standoff height and the bump pitch determined in the underfill environment are greater than in the air environment. As the power supply voltage increases, the standoff height and bump pitch become more significant. A powerful optimal window for bump design parameters is thus established.     

Origin and evolution of voids in electroless Ni during soldering reaction

The interfacial voids in Ni₂SnP were studied by high-resolution transmission electron microscopy. These voids were found to be responsible for many types of failure in electronic solder joints, but so far, detailed investigation of these voids has been pursued in a only few studies because of the need for advanced analytical techniques. The interaction of Sn₃Ag_0.5Cu with electroless Ni/immersion Au was investigated in this study. The microstructures during reflow were quenched to understand the evolution of these voids. Different peak reflow temperatures were adopted to analyze the change in the void density. Then, the effect of the number of reflow cycles on the void density was investigated. Two types of interfacial voids were found: one in the Ni₃P region and the other in the Ni₂SnP region. The voids in Ni₂SnP were connected to each other to form a void line. The void density increased with the number of reflow cycles, but not with the peak reflow temperature. These results confirmed that the voids in Ni₂SnP were more fragile and responsible for most of the interfacial cracks. Void nucleation and coalescence were modeled on the basis of the Johnson–Mehl–Avrami–Kolmogorov theory. The experimental data agreed well with the model data. The mechanism of the void nucleation and coalescence was then discussed.     

Evaluating schedule delay causes for private participating public construction works under the Build-Operate-Transfer model

Project delivery method of Build-Operate-Transfer (BOT) increases the commencement probability of public construction works through private investments. Public construction works worldwide that adopt the BOT model as their project delivery method are increasing gradually. Although many BOT projects have been implemented at various stages, some projects encounter major obstacles for advancement. This study attempts to identify the delay causes in various stages of BOT projects. Opinions of BOT participants’ replies are solicited using two questionnaire surveys. Those outcomes are analyzed using by traditional statistical methods and structural equation modeling method. Study results reveal that the stage of ‘negotiation and signing of concession agreement’ is the most essential stage, in which ‘improper contract planning,’ ‘debt problem’ and ‘uncertainty on political issues and government-finished items’ are the most significant delay causes. Identified causes of delay can be used to prevent the postponement of future BOT projects.     

Anomalous first normal stress difference behavior of polymer nanocomposites and liquid crystalline polymer composites

The first normal stress difference (N₁) behavior of polymer nanocomposites and liquid crystalline polymer (LCP) composites is a measure of elasticity and is affected by shear stress as a result of morphological alterations at the molecular and nanostructure levels. In this study, the steady shear rheological behaviors of polylactide (PLA) and nanographite platelet (NGP) bionanocomposites containing 1, 2, 3, and 5 wt% nanofiller were investigated. The shear rheological properties of glass fiber‐filled LCPs (filler aspect ratio > 100) were also examined. One of the objectives of this study was to obtain a correlation between N₁, filler contents, and shear stress/rate of the measurements. The results suggest that N₁ in PLA/NGP bionanocomposites is dependent on the level of filler loading as well as the shear rate beyond a critical value. For the LCP systems, N₁ is positive for the unfilled and negative for the glass fiber‐filled LCPs, respectively. A novel rectangular hyperbola model was successfully developed and utilized to fit the N₁ data of the neat PLA and PLA/NGP composites as well as the unfilled LCPs. The anomalous N₁ behavior of PLA/NGP and LCP composites was also thoroughly discussed in this study. POLYM. ENG. SCI., 54:1300–1312, 2014. © 2013 Society of Plastics Engineers     

Novel Temperature Stable Li2MnO3 Dielectric Ceramics with High Q for LTCC Applications

Novel microwave dielectric ceramics in the Li₂MnO₃ system with high Q prepared through a conventional solid‐state route had been investigated. All the specimens exhibited single phase ceramics sintered in the temperature range 1140°C–1230°C. The microwave dielectric properties of Li₂MnO₃ ceramics were strongly correlated with sintering temperature and density. The best microwave dielectric properties of ε_r = 13.6, Q × f = 97 000 (GHz), and τ_f = ?5.2 ppm/°C could be obtained as sintered at 1200°C for 4 h. BaCu(B₂O₅) (BCB) could effectively lower the sintering temperature from 1200°C to 930°C and slightly induced degradation of the microwave dielectric properties. The Li₂MnO₃ ceramics doped with 2 wt% BaCu(B₂O₅) had excellent dielectric properties of ε_r = 11.9, Q × f = 80 600 (GHz), and τ_f = 0 ppm/°C. With low sintering temperature and good dielectric properties, the BCB added Li₂MnO₃ ceramics are suitable candidates for LTCC applications in wireless communication system.     

Ion exchange recovery of Ni(II) from simulated electroplating waste solutions containing anionic ligands

Ion exchange is widely used for the recovery and removal of metals from process and waste streams in chemical process industries. The Na-form of strong-acid Purolite NRW-100 resin was used to recover Ni(II) from a simulated electroplating waste solution containing NiSO4, NH4Cl, NaH2PO4, and citrate. A set of mass balance equations that take into account possible aqueous complexation reactions was used to establish the pH diagram of Ni(II) species in the presence of anionic ligand citrate or phosphate. Experiments were performed as a function of initial solution pH (0.5-6.0), initial concentration of Ni(II) (0.85-11.9 mol/m3), and temperature (15-45 degrees C). It was shown that the amount of Ni(II) exchanged leveled off when the equilibrium pH was higher than around 2.5. The exchange isotherms obtained at various equilibrium pH values were well fitted by the Langmuir equation. The enthalpy of Ni(II) exchange was also evaluated based on the Langmuir constant. Finally, the kinetics of the present ion exchange process was analyzed.