A survey of outlier detection in high dimensional data streams

The rapid evolution of technology has led to the generation of high dimensional data streams in a wide range of fields, such as genomics, signal processing, and finance. The combination of the streaming scenario and high dimensionality is particularly challenging especially for the outlier detection task. This is due to the special characteristics of the data stream such as the concept drift, the limited time and space requirements, in addition to the impact of the well-known curse of dimensionality in high dimensional space. To the best of our knowledge, few studies have addressed these challenges simultaneously, and therefore detecting anomalies in this context requires a great deal of attention. The main objective of this work is to study the main approaches existing in the literature, to identify a set of comparison criteria, such as the computational cost and the interpretation of outliers, which will help us to reveal the different challenges and additional research directions associated with this problem. At the end of this study, we will draw up a summary report which summarizes the main limits identified and we will detail the different directions of research related to this issue in order to promote research for this community.     

撞击流反应器制备纳米铜粉的研究

在浸没循环撞击流反应器(SCISR)中,采用五水硫酸铜为原料,以硼氢化钾为还原剂制备纳米铜粉。确定了制备纳米铜粉的适宜工艺条件是:Cu2+的浓度为0.2 mol/L,硼氢化钾与硫酸铜物质的量比为1∶1,氢氧化钾与硼氢化钾物质的量比为9∶1,反应温度为40℃,反应时间为10 min,2%(质量分数)聚乙烯吡咯烷酮用量为80 mL。采用TEM和XRD对产品进行表征。所得产品呈近似球形,直径20³0 nm;纯度高,其收率高于98%。     

Land inputs of trace metals, major elements, particulate organic carbon and suspended solids to an industrial coastal bay of the NE Atlantic

Rivers, streams and municipal and industrial effluents flowing into the Ferrol Ria (NW Spain) were analyzed for dissolved and particulate trace elements (Cd, Cu, Pb, Zn), particulate major elements (Al, Fe, Si), particulate organic carbon and nitrogen (POC and PON), and total suspended solids. Trace metal clean techniques were applied. Mean annual fluxes of these components were calculated. Dissolved trace metal concentrations in the major freshwater inputs were found to be within typical values for uncontaminated rivers: Cd: 0.020-0.035 nM; Cu: 11.7-19.2 nM; Pb: 0.40-0.71 nM and Zn: 18-54 nM. Two sources of suspended particulate matter (SPM) were observed: (i) a detrital SPM, which becomes more important at high river discharges, with metal concentrations tending to lithogenic values; (ii) an organic- and metal-rich SPM, which becomes dominant at low discharges. Municipal and industrial effluents in the northern shore, despite of constitute a minor freshwater contribution to the bay, were responsible for more than 50% of total inputs of Cu, Cd, Pb, Zn, POC and PON. The fluxes of trace metals obtained for the Ferrol Ria are in the range of other inhabited world semi-enclosed embayments.     

Sediment and discharge yields within a minimally disturbed,headwater watershed in North Central Pennsylvania,USA, with an emphasis on Superstorm Sandy

We estimated discharge and suspended sediment (SS) yield in a minimally disturbed watershed in North Central Pennsylvania, USA, and compared a typical storm (September storm, 4.80 cm) to a large storm (Superstorm Sandy, 7.47 cm rainfall). Depending on branch, Sandy contributed 9.7–19.9 times more discharge and 11.5–37.4 times more SS than the September storm. During the September storm, the upper two branches accounted for 60.6% of discharge and 88.8% of SS at Lower Branch; during Sandy these percentages dropped to 36.1% for discharge and 30.1% for SS. The branch with close proximity roads had over two‐three times per area SS yield than the branch without such roads. Hysteresis loops showed typical clockwise patterns for the September storm and more complicated patterns for Sandy, reflecting the multipeak event. Estimates of SS and hysteresis in minimally disturbed watersheds provide useful information that can be compared spatially and temporally to facilitate management.     

Looking into the TESSERACT: Time-drifts in event streams using series of evolving rolling averages of completion times

Business processes are dynamic and change due to diverse factors. While existing approaches aim to detect drifts in the process structure, Tesseract looks for temporal drifts in activity interim times. This orthogonal view on the process extends the traditional data cube of events – case id, activities and timestamps – by a fourth dimension and improves the operational support by a visualization of temporal drifts in real-time.Insights about temporal deviations lead to an augmented awareness of imminent failures or improved service times. The detection of related structural concept drifts can be improved by early warning, as operation times of critical parts often increase before they catastrophically fail.     

Simultaneous heat exchanger network synthesis for direct and indirect heat transfer inside and between processes

Process plants are typically divided into different process parts having specific processing tasks with possibly different ownership. Heat integration between these processes can increase the energy- and economic efficiency for both the overall plant and the individual processes. In this paper we present a heat exchanger network synthesis MINLP-model that allows simultaneous heat integration directly between streams in the same process and both directly and indirectly between streams in different processes. The indirect heat transfer is accomplished by using intermediate streams. Two examples, one small explanatory one and one from the literature, are optimized. The results verify that the model works logically.     

Real-time data mining of massive data streams from synoptic sky surveys

The nature of scientific and technological data collection is evolving rapidly: data volumes and rates grow exponentially, with increasing complexity and information content, and there has been a transition from static data sets to data streams that must be analyzed in real time. Interesting or anomalous phenomena must be quickly characterized and followed up with additional measurements via optimal deployment of limited assets. Modern astronomy presents a variety of such phenomena in the form of transient events in digital synoptic sky surveys, including cosmic explosions (supernovae, gamma ray bursts), relativistic phenomena (black hole formation, jets), potentially hazardous asteroids, etc. We have been developing a set of machine learning tools to detect, classify and plan a response to transient events for astronomy applications, using the Catalina Real-time Transient Survey (CRTS) as a scientific and methodological testbed. The ability to respond rapidly to the potentially most interesting events is a key bottleneck that limits the scientific returns from the current and anticipated synoptic sky surveys. Similar challenge arises in other contexts, from environmental monitoring using sensor networks to autonomous spacecraft systems. Given the exponential growth of data rates, and the time-critical response, we need a fully automated and robust approach. We describe the results obtained to date, and the possible future developments.     

实现数字电视机顶盒选单广告功能的研究

提供了一种数字电视机顶盒选单广告功能的实现方式,给出了重要问题的解决办法。通过数字电视机顶盒选单广告功能的实现,可使广电网络公司以少量的投入获得更大的经济效益。     

新型多参数水质分析仪流路控制系统的设计

以单片机为核心,运用十联体电磁阀、三通阀和微型步进蠕动泵等流控器件设计新型多流路控制系统.对比测试结果表明,该系统能完成20多种流路切换,进样速度快,加样误差小于1%,能快速、高效地清洗进样通道,并避免交叉污染,而且成本低、不易堵塞、稳定性良好.     

对喷流协同蒸汽相变对燃煤细颗粒脱除性能的影响

以燃煤锅炉产生的含尘热烟气为对象,采用电称低压冲击器（electrical low pressure impactor,ELPI）和Vaisala-HMT337型温湿度变送器等测试仪器,研究倾斜对喷流与蒸汽相变相结合的方法对燃煤细颗粒的脱除性能,实验考查烟气对喷流速、烟气对喷间距、蒸汽添加量、除雾器类型、添加润湿剂等对细颗粒脱除效率的影响规律。研究结果表明：采用对喷流和蒸汽相变技术相结合的方法可以高效脱除细颗粒物;细颗粒脱除效率随烟气对喷间距的增大先提高后降低,随烟气流速和蒸汽添加量的增大而提高;相变室出口安装丝网除雾器的脱除效果优于采用板波纹除雾器;烟气中添加挥发性乙二醇润湿剂对细颗粒脱除有一定的促进效果。