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71.
Judith A. Haney 《Journal of Systems Integration》1995,5(4):349-360
This report is a summary of the continuing efforts of several teams at the Naval Surface Warfare Center, Dahlgren Divsion (NSWCDD) to evaluate technologies and to define and refine a process to reengineer Navy legacy CMS-2 code into Ada. This effort involves tool and technology evaluation, methodology definition, and cost model definition.For systems developed in CMS-2, a Navy specific high order language, consideration must be given as to the most cost effective method of converting to the current high order language of choice, i.e., Ada, without losing the legacy lessons learned. NSWCDD engineers evaluated three translation tools, evaluated reverse engineering technologies, and defined both a process and a methodology to incrementally transition Navy CMS-2 code into Ada. The source code used for the evaluation is from the AEGIS Weapon System and the distributed, open environment is the High Performance Distributed Computing Program co-sponsored by the Advanced Research Projects Agency and the AEGIS Program Manager.Many of the issues identified throughout these studies are unresolved, but software engineers are continuing to evaluated the impacts of transitioning to commercial environments and Ada. Some of the issues that are being studied follow: testing of distributed systems; system level integration; lack of time-stamped instrumentation: and reliability in commercial-off-the shelf environments. The Navy is in the early stages of identifying impacts of transitioning to Ada, commercial environments, and distributed architectures. NSWCDD is gathering data to confirm that capturing legacy systems, whether it is code or design ideas, is essential to minimizing the cost and the risk of these transitions. It is also evident that technology is neither mature nor ideal yet to satisfy the identified needs for capturing the legacy of a proven system. Translation, while useful to a point, is not suitable alone as a solution to the transition equation. 相似文献
72.
目的 为探究微波降解EGCG方法制备EGC的效果,以EGC得率最大化为目标,探究微波降解的最佳工艺参数,并建立反映各参数间关系的二次多元方程模型。方法 本研究采用EGCG溶液为原料,运用微波加热降解EGCG制备EGC,通过梯度设置EGCG浓度、微波时长、微波强度三个工艺参数,进行单因素实验、响应面分析及最佳工艺组合验证实验,优化确定EGCG微波降解制备EGC的最佳工艺参数。结果 综合单因素实验及响应面分析,得到的最佳微波降解参数为:EGCG浓度5mg/ml、微波时长3.5min、微波强度为400W,且利用响应面法建立了EGC得率(Y)与EGCG浓度(A)、微波时长(B)、微波强度(C)的二次多元方程模型:Y=59.52+8.38*A+5.38*B+3.53*C-4.04*AB+6.92*AC-9.19*BC-9.99A2+0.0786*B2-15.36*C2,模型中,EGC得率最高可达62.08%。对最佳微波降解工艺参数进行验证实验,EGC得率为63.40%,与模型预测值接近。结论 运用微波降解EGCG制备EGC具有操作简单,可行性高的优势,且EGC得率稳定性高。 相似文献
73.
为降低外转子永磁同步电机(ERPMSM) 作为皮带输送机驱动电机时的永磁体成本并提高电机性能,提出基于响应面法(RSM)和改进多目标粒子群优化(IMOPSO)算法的优化设计方法。在建立电机基本结构的基础上,将永磁体尺寸、气隙长度、槽口宽度等作为优化参数,将永磁体成本、输出转矩、转矩脉动等作为优化目标。通过参数灵敏度分析筛选出显著参数,基于RSM结合有限元仿真建立样本空间,并拟合出优化目标和优化参数的函数关系,通过IMOPSO寻优。最后对比优化前后的方案结果,所提多目标优化算法准确可靠且具有更好的收敛性和多样性,能够在降低永磁体成本的同时优化电机的性能。 相似文献
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76.
Sachin Mohal 《Materials and Manufacturing Processes》2017,32(3):263-273
The demand for miniaturized products having a glossy surface or nano-level surface is increasing exponentially in automobile, aerospace, biomedical, and semiconductor industries. The mirror-like surface finish has generated a need to develop advanced machining processes. The addition of powder particle into electric discharge machining (EDM) oil is considered a promising technique to achieve surface integrity at the miniaturization level. In this research, the Al–10%SiCp metal matrix composite (MMC) has been machined after mixing the appropriate amount of multiwalled carbon nanotubes (MWCNTs) into the EDM dielectric fluid. An advanced experimental setup has been designed and fabricated in the laboratory for conducting the experiments. This proposed technology is called nano powder mixed electric discharge machining (NPMEDM). The input parameters of NPMEDM are also optimized using central composite rotatable design (CCRD) based on response surface methodology (RSM) in order to obtain the best surface finish and material removal rate (MRR). The MRR has been increased by 38.22% and surface finish has been improved by 46.06% after mixing the MWCNTs into the EDM dielectric fluid. The results indicate that the combination of parameters A5, B5, C5, and D5 might have produced maximum MRR, whereas A1, B1, C1, and D3 have produced minimum surface roughness (SR). 相似文献
77.
Most of the published literature on robust design is basically concerned with a single response. However, the reality is that common industrial problems usually involve several quality characteristics, which are often correlated. Traditional approaches to multidimensional quality do not offer much information on how much better or worse a process is when finding optimal settings. Köksoy and Fan [Engineering Optimization 44 (8): 935–945] pointed out that the upside-down normal loss function provides a more reasonable risk assessment to the losses of being off-target in product engineering research. However, they only consider the single-response case. This article generalizes their idea to more than one response under possible correlations and co-movement effects of responses on the process loss. The response surface methodology has been adapted, estimating the expected multivariate upside-down normal loss function of a multidimensional system to find the optimal control factor settings of a given problem. The procedure and its merits are illustrated through an example. 相似文献
78.
Reliability Analysis Method on Repairable System with Standby Structure Based on Goal Oriented Methodology 下载免费PDF全文
Xiao‐jian Yi B.S. Dhillon Jian Shi Hui‐na Mu Hai‐ping Dong 《Quality and Reliability Engineering International》2016,32(7):2505-2517
This paper presents a reliability analysis method on repairable system with standby structure based on goal oriented (GO) methodology. Firstly, a new combination of GO operator, which is composed of a new logical GO operator named Type 18A operator and a new auxiliary GO operator named Type 20 operator, is created to represent standby mode. The availability formula of standby equipment with translation exception is deduced based on Markov process theory. Then, the application method of combination of GO operator for standby mode and the analysis process of repairable system with standby structure based on GO method are proposed. Thirdly, this new combination of GO operator is applied in availability analysis of the hydraulic oil supply system of power‐shift steering transmission. Finally, the results obtained by the new GO method are compared with the results of fault tree analysis, Monte Carlo simulation, GO methods using Type 2 operator and Type 18 operator to represent the standby mode, respectively. And the comparison results show that this new GO method is applicable and reasonable for reliability analysis of repairable system with standby structure. All in all, this paper provides guidance for reliability analysis of repairable systems with standby structure. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
79.
以炼铁烧结机头除尘灰(烧结灰)为实验原料,通过XRF、XRD、SEM-EDS手段对原料进行表征,采用酸性硫脲法浸出烧结灰提取银。在单因素实验的基础上,使用响应曲面法(RSM)对烧结灰中提取银的工艺条件进行优化,以炼铁烧结灰中银的浸出率为响应值,选取对硫脲浸出烧结灰提银过程有显著影响的变量(反应温度、硫脲浓度、浸出时间)作为考察因素,采用Central Composite Design(CCD)中心设计方案以三因素五水平设计实验,得到最优的提银工艺条件,并获得拟合度高的二阶多项式模型。结果表明:硫脲浸出烧结灰中银的最佳工艺为反应温度50℃、硫脲浓度22g/L、浸出时间90min;在最佳提取条件下,银浸出率的模型预测值为89.38%,实验真实银的浸出率为89.9%,其相对误差为0.52%,表明实际值与模型预测值接近,可用于预测烧结灰提取银的浸出过程。 相似文献
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