Enabling high-dimensional range queries using <Emphasis Type="Italic">k</Emphasis>NN indexing techniques: approaches and empirical results

Many modern search applications are high-dimensional and depend on efficient orthogonal range queries. These applications span web-based and scientific needs as well as uses for data mining. Although k-nearest neighbor queries are becoming increasingly common due to mobile and geospatial applications, orthogonal range queries in high-dimensional data remain extremely important and relevant. For efficient querying, data is typically stored in an index optimized for either kNN or range queries. This can be problematic when data is optimized for kNN retrieval and a user needs a range query or vice versa. Here, we address the issue of using a kNN-based index for range queries, as well as outline the general computational geometry problem of adapting these systems to range queries. We refer to these methods as space-based decompositions and provide a straightforward heuristic for this problem. Using iDistance as our applied kNN indexing technique, we also develop an optimal (data-based) algorithm designed specifically for its indexing scheme. We compare this method to the suggested naïve approach using real world datasets. The data-based algorithm consistently performs better.     

Empirical process of long-range dependent sequences when parameters are estimated

In this paper, we study the asymptotic behavior of empirical processes when parameters are estimated, assuming that the underlying sequence of random variables is long-range dependent. We show completely different phenomena compared to i.i.d. situation, as well as compared to ordinary empirical processes of long-range dependent sequences. Applications include Kolmogorov–Smirnov and Cramer–Smirnov–von Mises goodness-of-fit statistics.     

Mental health literacy,stigma, and help-seeking behaviors among male college students

Objective: Mental health literacy (MHL) is low in college-aged men potentially resulting in impaired mental wellbeing. This study assessed MHL, psychosocial determinants, and help-seeking behaviors among male university students. Participants: Male undergraduate and graduate students were surveyed in Spring 2017 (n = 1,242) at a large southeastern university in the United States. Methods: Preexisting validated scales for MHL, psychosocial determinants, and help-seeking intention were used in measurement and demographic variables were collected. T-tests and one-way ANOVA were performed to measure differences between groups. Results: Participants showed low scores for all constructs with statistically significant differences between undergraduate and graduate students, as well as between races and major classifications. Undergraduate men had moderate MHL and low intentions to seek professional care. Conclusions: Interventions focusing on increasing mental health knowledge and improving beliefs can improve MHL among male college students. Further, interventions should be tailored for racial groups and major classifications.     

Older age and a higher EHRA score allow higher levels of frailty syndrome to be predicted in patients with atrial fibrillation

Background: There is no research that evaluates the relationship between the severity of the symptoms of atrial fibrillation (AF), the presence of frailty syndrome and acceptance of the illness.

Methods: The study included 132 patients aged 72.7?±?6.73 with diagnosed AF. The severity of the symptoms of AF was determined according to European Heart Rhythm Association (EHRA) guidelines, frailty syndrome was assessed using the Tilburg frailty indicator (TFI) and the acceptance of the illness was assessed using the acceptance of illness scale (AIS). A standard statistical comparison and multiple regression analysis using the stepwise method were performed.

Results: In patients with AF, frailty was 5.31?±?2.69 (TFI). Frailty syndrome was diagnosed in 59.8% of the AF patients who had a score of 7.17?±?1.72. A higher level of EHRA score was connected with a smaller degree of the acceptance of the illness p?=?0.0000. The multiple regression model indicated that age (p?=?0.0009) and the severity of the symptoms (p?=?0.0001) are important predictors of frailty syndrome.

Conclusions: There is a relationship between the presence of frailty syndrome and the intensity of the symptoms and the acceptance of AF. Age and the EHRA score permitted higher levels of frailty syndrome to be predicted.     

Statistical Inference for Curved Fibrous Objects in 3D – Based on Multiple Short Observations of Multivariate Autoregressive Processes

This paper deals with statistical inference on the parameters of a stochastic model, describing curved fibrous objects in three dimensions, that is based on multivariate autoregressive processes. The model is fitted to experimental data consisting of a large number of short independently sampled trajectories of multivariate autoregressive processes. We discuss relevant statistical properties (e.g. asymptotic behaviour as the number of trajectories tends to infinity) of the maximum likelihood (ML) estimators for such processes. Numerical studies are also performed to analyse some of the more intractable properties of the ML estimators. Finally the whole methodology, i.e., the fibre model and its statistical inference, is applied to appropriately describe the tracking of fibres in real materials.     

波兰第三共和国新近历史的研究状况

20世纪80年代,波兰史学界围绕当代史展开了激烈的争论,并出现了两种新近历史形象的对立,即正式历史与未经过审查出版的对立性历史。新近历史焦点在于确认主体——历史学家——与他的研究客体相比较,在时间上靠近被讨论或者被记录下来的事件,在时间线上不可能有一个固定点,它随流逝的时间及可延伸的历史情景而行进。波兰对新近历史新形象的讨论无疑是更完整的波兰历史研究的一部分。这些讨论的参照点既有与我们有关过去知识的新形式相关的争论及其在美国和西欧学术中呈现的社会地位,也有在其他后共产党国家致力于历史形象的全国性争论。