Multiphysics modeling and optimization of mechatronic multibody systems

Modeling mechatronic multibody systems requires the same type of methodology as for designing and prototyping mechatronic devices: a unified and integrated engineering approach. Various formulations are currently proposed to deal with multiphysics modeling, e.g., graph theories, equational approaches, co-simulation techniques. Recent works have pointed out their relative advantages and drawbacks, depending on the application to deal with: model size, model complexity, degree of coupling, frequency range, etc. This paper is the result of a close collaboration between three laboratories, and aims at showing that for “non-academic” mechatronic applications (i.e., issuing from real industrial issues), multibody dynamics formulations can be generalized to mechatronic systems, for the model generation as well as for the numerical analysis phases. Model portability being also an important aspect of the work, they must be easily interfaced with control design and optimization programs. A global “demonstrator”, based on an industrial case, is discussed: multiphysics modeling and mathematical optimization are carried out to illustrate the consistency and the efficiency of the proposed approaches.     

Mining for trigger events with survival analysis

This paper discusses a new application of data mining, quantifying the importance of responding to trigger events with reactive contacts. Trigger events happen during a customer’s lifecycle and indicate some change in the relationship with the company. If detected early, the company can respond to the problem and retain the customer; otherwise the customer may switch to another company. It is usually easy to identify many potential trigger events. What is needed is a way of prioritizing which events demand interventions. We conceptualize the trigger event problem and show how survival analysis can be used to quantify the importance of addressing various trigger events. The method is illustrated on four real data sets from different industries and countries.     

The ability of the Millon Clinical Multiaxial Inventory--Third Edition to detect malingering.

This study investigated the ability of the Millon Clinical Multiaxial Inventory--Third Edition (MCMI-III) to discriminate students malingering psychopathology (n=106) from bona fide psychiatric inpatients (n=202). Students were randomly assigned to a fake-bad or an honest-responding condition. Analyses investigated the ability of the modifier indices to discriminate fake-bad group participants from the psychiatric inpatients. Scale X raw cutoff score >178 yielded a positive predictive power (PPP) of 0.0, a negative predictive power (NPP) of 63.1, and a hit rate of 63.1%. Optimal cutoff scores were developed. Scale X Base Rate (BR) >84 provided a PPP of 55.6, an NPP of 72.1, and a hit rate of 65.2%. Scale Y BR     

New encapsulation development for fine pitch IC devices

The continuous reduction of chip size driven by the market demand has a significant impact on circuit design and assembly process of IC packages. Shrinking chip size and increasing I/O counts require finer bond pad pitch and bond pad size for circuitry layout. As a result, serious wire deflection during transfer molding process could make adjacent wires short, and this issue becomes more critical as a smaller wire diameter has to be applied for the finer pitch wire bonded IC devices.This paper presents a new encapsulation process development for 50 μm fine pitch plastic ball grid array package. Since reduced wire diameter decreases the bending strength of bonded wires significantly, wire deflection during molding process becomes quite serious and critical. Experiments on conventional transfer molding were conducted to evaluate wire span threshold with 23.0 μm diameter gold wire. The results show that the wire span threshold is about 4.1 mm, which is much shorter than the wire span threshold of over 5.0 mm for wire with 25.4 μm diameter. Finite element analysis shows there is a significant difference in the wire deflection between 23.0 μm gold wire and 25.4 μm gold wire diameter under the same action of mold flow. A novel encapsulation method is introduced using non-sweep solution. The wire span could be extended to over 5.0 mm with wire sweep less than 1%. Reliability tests conducted showed that all the units passed 1000 temperature cycles (−55 to 125 °C) with JEDEC moisture sensitivity level 2a (60 °C/60% relative humidity for 120 h) and 3 times reflow (peak temperature at 220–225 °C). It is believed that this solution could efficiently overcome the risk of wire short issues and improve the yield of ultra fine pitch wire bonds in high-volume production.     

利用试井资料评价压裂地质效果

依据裂缝井试井解释理论，利用实测试井资料对压裂地质效果进行了深入剖析。通过部分探井措施后增产效果实例研究，把压裂地质效果分为三种类别；并从地质角度出发，详细分析了优选压裂井层的依据。为油气井合理开发和制定增产措施提供参考依据。     

Energy management for commercial servers

Servers: high-end, multiprocessor systems running commercial workloads, have typically included extensive cooling systems and resided in custom-built rooms for high-power delivery. Recently, as transistor density and demand for computing resources have rapidly increased, even these high-end systems face energy-use constraints. Commercial-server energy management now focuses on conserving power in the memory and microprocessor subsystems. Because their workloads are typically structured as multiple application programs, system-wide approaches are more applicable to multiprocessor environments in commercial servers than techniques that primarily apply to single-application environments, such as those based on compiler optimizations.     

Complementary Justice: Effects of "Poor but Happy" and "Poor but Honest" Stereotype Exemplars on System Justification and Implicit Activation of the Justice Motive.

It was hypothesized that exposure to complementary representations of the poor as happier and more honest than the rich would lead to increased support for the status quo. In Study 1, exposure to "poor but happy" and "rich but miserable" stereotype exemplars led people to score higher on a general measure of system justification, compared with people who were exposed to noncomplementary exemplars. Study 2 replicated this effect with "poor but honest" and "rich but dishonest" complementary stereotypes. In Studies 3 and 4, exposure to noncomplementary stereotype exemplars implicitly activated justice concerns, as indicated by faster reaction times to justice-related than neutral words in a lexical decision task. Evidence also suggested that the Protestant work ethic may moderate the effects of stereotype exposure on explicit system justification (but not implicit activation). (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Modeling language acquisition in atypical phenotypes.

An increasing number of connectionist models have been proposed to explain behavioral deficits in developmental disorders. These simulations motivate serious consideration of the theoretical implications of the claim that a developmental disorder fits within the parameter space of a particular computational model of normal development. The authors examine these issues in depth with respect to a series of new simulations investigating past-tense formation in Williams syndrome. This syndrome and the past-tense domain are highly relevant because both have been used to make strong theoretical claims about the processes underlying normal language acquisition. The authors conclude that computational models have great potential to advance psychologists' understanding of developmental deficits because they focus on the developmental process itself as a pivotal causal factor in producing atypical phenotypic outcomes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The effects of attrition on baseline comparability in randomized experiments in education: A meta-analysis.

Using meta-analysis, randomized experiments in education that either clearly did or clearly did not experience student attrition were examined for the baseline comparability of groups. Results from 35 studies suggested that after attrition, the observed measures of baseline comparability of groups did not differ more than would be expected given sampling error. The degree of either overall or differential attrition did not relate to baseline comparability, a finding that held under sensitivity analyses. Also, both overall and differential attrition rates were unrelated to posttest effect sizes. All of these analyses, however, lacked sufficient statistical power to detect small but potentially meaningful effects. Results suggest caution is warranted when applying quality scales and other blanket rules pertaining to attrition that are meant to either serve as inclusion-exclusion criteria or in scoring study quality. Much greater attention is needed to both the reporting of attrition in primary studies and to the development of conceptual and empirical models of the attrition process. These developments would aid further investigation of the relation between attrition and study outcomes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

常减压蒸馏装置换热网络的节能优化

利用夹点技术理论对耗能严重的某炼油厂常减压蒸馏装置进行用能诊断分析;并结合热力学原理得到两种优化换热网络,节能效果显著。