On mining approximate and exact fault-tolerant frequent itemsets

Robust frequent itemset mining has attracted much attention due to the necessity to find frequent patterns from noisy data in many applications. In this paper, we focus on a variant of robust frequent itemsets in which a small amount of “faults” is allowed in each item and each supporting transaction. This problem is challenging since computing fault-tolerant support count is NP-hard and the anti-monotone property does not hold when the amount of allowable faults is proportional to the size of the itemset. We develop heuristic methods to solve an approximation version of the problem and propose speedup techniques for the exact problem. Experimental results show that our heuristic algorithms are substantially faster than the state-of-the-art exact algorithms while the error is acceptable. In addition, the proposed speedup techniques substantially improve the efficiency of the exact algorithms.     

虎奶菇菌丝体细胞壁成分分析及多糖结构表征

该文以液态发酵的虎奶菇(Pleurotus tuber-regium,PTR)菌丝体为原料,对PTR菌丝体细胞壁(PTR-MCW)的组分进行分析,并阐明细胞壁骨架结构。采用不同提取强度的溶剂分离MCW的可溶性成分,对各组分进行含量测定、化学成分分析及基本结构表征。结果表明,PTR-MCW主要由4部分组成:热水提多糖和蛋白质复合物的外层,常温碱提的杂多糖部分,热碱提的高度支化杂多糖部分和碱不溶性多糖-几丁质复合物部分,这4种组分在PTR-MCW中的比例为2.06∶22.06∶46.97∶18.95。占主要组分的热碱提多糖经纯化后得到纯多糖MHA-I,单糖组成和甲基化分析表明其糖苷键类型包括T-木糖、T-鼠李糖、T-葡萄糖、1,3-葡萄糖、1,6-葡萄糖、1,4-葡萄糖、1,3,6-葡萄糖、1,4,6-葡萄糖、1,3,6-甘露糖,摩尔比为2.01∶1.00∶27.64∶8.19∶38.22∶20.88∶14.38∶6.98∶3.22,该多糖的分支度(degree of branching,DB)为0.45,FT-IR分析鉴定MHA-I中主要为β-糖苷键。SEC-MALLS分析表明,超支化杂多糖MHA-I的分子量为4.502×10^4 g/mol,回转半径为33.2 nm。电镜结果显示,MHA-I为具有超支化结构的多糖,在干燥的粉末状态下呈现准球形结构。该研究成果为虎奶菇多糖的开发及活性研究提供一定的理论依据。     

Spouse criticism and support: Their association with coping and psychological adjustment among women with rheumatoid arthritis.

Examined whether psychological adjustment of women with rheumatoid arthritis would be related to the support and criticism the patient received from the husband. Interviews were conducted with the husbands of 103 women with rheumatoid arthritis. Spouse interviews were content coded for critical remarks. Wives completed a revised version of the Ways of Coping Scale and a scale of the perceived supportiveness of the spouse. Husbands completed rating scales assessing their perceived vulnerability to illness and the degree of burden they experienced in providing assistance to their wives. Path analyses revealed that patient adjustment was significantly related to the attitude of the spouse. Patients with a highly critical spouse engaged in more maladaptive coping behaviors and reported a poorer psychological adjustment. Independent of spousal criticism, patients who perceived their spouse as being supportive engaged in more adaptive coping. A path model was fit to the data that suggested that the spouse may affect adjustment indirectly through influencing the patient's selection of adaptive or maladaptive coping responses. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

AdaBoost Models for Corporate Bankruptcy Prediction with Missing Data

Very little existing research in corporate bankruptcy prediction discusses modeling where there are missing values. This paper investigates AdaBoost models for corporate bankruptcy prediction with missing data. Three AdaBoost models integrated with different imputation methods are tested on two data sets with very different sample sizes. The experimental results show that the AdaBoost algorithm combined with imputation methods has strong predictive accuracy in both data sets and it is a useful alternative for bankruptcy prediction with missing data.     

Robust Statistical Methods for Empirical Software Engineering

There have been many changes in statistical theory in the past 30 years, including increased evidence that non-robust methods may fail to detect important results. The statistical advice available to software engineering researchers needs to be updated to address these issues. This paper aims both to explain the new results in the area of robust analysis methods and to provide a large-scale worked example of the new methods. We summarise the results of analyses of the Type 1 error efficiency and power of standard parametric and non-parametric statistical tests when applied to non-normal data sets. We identify parametric and non-parametric methods that are robust to non-normality. We present an analysis of a large-scale software engineering experiment to illustrate their use. We illustrate the use of kernel density plots, and parametric and non-parametric methods using four different software engineering data sets. We explain why the methods are necessary and the rationale for selecting a specific analysis. We suggest using kernel density plots rather than box plots to visualise data distributions. For parametric analysis, we recommend trimmed means, which can support reliable tests of the differences between the central location of two or more samples. When the distribution of the data differs among groups, or we have ordinal scale data, we recommend non-parametric methods such as Cliff’s δ or a robust rank-based ANOVA-like method.     

Parallel tempering simulation of the three-dimensional Edwards–Anderson model with compact asynchronous multispin coding on GPU

Monte Carlo simulations of the Ising model play an important role in the field of computational statistical physics, and they have revealed many properties of the model over the past few decades. However, the effect of frustration due to random disorder, in particular the possible spin glass phase, remains a crucial but poorly understood problem. One of the obstacles in the Monte Carlo simulation of random frustrated systems is their long relaxation time making an efficient parallel implementation on state-of-the-art computation platforms highly desirable. The Graphics Processing Unit (GPU) is such a platform that provides an opportunity to significantly enhance the computational performance and thus gain new insight into this problem. In this paper, we present optimization and tuning approaches for the CUDA implementation of the spin glass simulation on GPUs. We discuss the integration of various design alternatives, such as GPU kernel construction with minimal communication, memory tiling, and look-up tables. We present a binary data format, Compact Asynchronous Multispin Coding (CAMSC), which provides an additional 28.4% speedup compared with the traditionally used Asynchronous Multispin Coding (AMSC). Our overall design sustains a performance of 33.5 ps per spin flip attempt for simulating the three-dimensional Edwards–Anderson model with parallel tempering, which significantly improves the performance over existing GPU implementations.     

Treatment adherence difficulties among children with cancer: the role of parenting style

Investigated the prevalence of treatment adherence problems among children undergoing cancer treatment and explored the relationship of sociodemographic factors, child functional status, and parenting style to these difficulties. Nurse ratings of adherence difficulties encountered during the cancer treatment regimen were completed on 77 children and their caregivers. A subset of caregivers also completed a measure of parenting attitudes and practices. Results indicated that certain adherence difficulties were related to the child's age and functional status, the family's socioeconomic status (SES), and parenting style. The child's age was related to adherence to procedure-related tasks; younger children had more frequent problems with completing these tasks. More functional children had a greater number of adherence problems. Families with a lower SES had more difficulties with timeliness and cancellations/delays of clinic appointments and promptness of reporting of the child's reactions to treatment. Children of caregivers who had a more "supportive" parenting style (were more sensitive to children's input, had a less restrictive attitude towards parenting, and were more nurturant) canceled and delayed fewer appointments, were on time more frequently for appointments, and reported reactions to treatment with less delay. Implications of these findings for future research on treatment adherence and for clinical interventions are discussed.     

Finding conclusion stability for selecting the best effort predictor in software effort estimation

Background: Conclusion Instability in software effort estimation (SEE) refers to the inconsistent results produced by a diversity of predictors using different datasets. This is largely due to the “ranking instability” problem, which is highly related to the evaluation criteria and the subset of the data being used. Aim: To determine stable rankings of different predictors. Method: 90 predictors are used with 20 datasets and evaluated using 7 performance measures, whose results are subject to Wilcoxon rank test (95 %). These results are called the “aggregate results”. The aggregate results are challenged by a sanity check, which focuses on a single error measure (MRE) and uses a newly developed evaluation algorithm called CLUSTER. These results are called the “specific results.” Results: Aggregate results show that: (1) It is now possible to draw stable conclusions about the relative performance of SEE predictors; (2) Regression trees or analogy-based methods are the best performers. The aggregate results are also confirmed by the specific results of the sanity check. Conclusion: This study offers means to address the conclusion instability issue in SEE, which is an important finding for empirical software engineering.     

Tilted Spiro‐Type Thermally Activated Delayed Fluorescence Host for ≈100% Exciton Harvesting in Red Phosphorescent Electronics with Ultralow Doping Ratio

Despite promising efficiency, the high fabrication cost due to the required high concentrations of noble metal based phosphors is still problematic for phosphorescent organic light‐emitting diodes (PhOLEDs). This situation becomes even serious considering some practical applications need high luminance, which in turn requires a higher concentration of emitters. A paradigm shift to circumvent these issues can be development of materials that are able to operate efficiently in very low concentrations ( < 1 wt%). Here, two thermally activated delayed fluorescence hosts ( OSTFPCN and OSTFPB ) with tilted spiro geometry, small singlet‐triplet splitting ( Δ E _st), and effective resonance energy transfer are developed. Within expectation, record performances with a power efficiency of 63.6 lm W^?1 and an external quantum efficiency (EQE) of 31.2% for the red phosphor Ir(MDQ)₂(acac) (2.0 wt%) are achieved with OSTFPCN as host. Additionally, a high power efficiency around 58 lm W^?1 is also gained even at an ultralow dopant concentration of 0.5 wt% for a OSTFPB based device. Mechanism studies demonstrate that efficiency roll‐off can be effectively suppressed in such low concentrations. These findings pave a new way to exploit low cost and high efficiency PhOLEDs.     

Mobile Fair Diary: hybrid interface for taking,browsing and sharing context-aware notes

This paper describes the Mobile Fair Diary (MFD), which is designed to allow a housing fair customer to make a personalized digital recording of his/her visit to a hectic fairground for later use. The MFD is a hybrid interface service comprising of an application for a camera equipped smart phone and a website accessed by a PC. The smart phone application is used for taking context-aware notes such as visual codes, photos, dictations and text. The notes are uploaded onto a website, where they can be viewed with a PC in a contextually ordered view for browsing, organizing and sharing. The MFD was empirically evaluated in a real-life environment of use with genuine end users by a large-scale field trial at a national housing fair. The results testify to the very successful design of the MFD with high usefulness.