Dense subgraph maintenance under streaming edge weight updates for real-time story identification

Recent years have witnessed an unprecedented proliferation of social media. People around the globe author, everyday, millions of blog posts, social network status updates, etc. This rich stream of information can be used to identify, on an ongoing basis, emerging stories, and events that capture popular attention. Stories can be identified via groups of tightly coupled real-world entities, namely the people, locations, products, etc, that are involved in the story. The sheer scale and rapid evolution of the data involved necessitate highly efficient techniques for identifying important stories at every point of time. The main challenge in real-time story identification is the maintenance of dense subgraphs (corresponding to groups of tightly coupled entities) under streaming edge weight updates (resulting from a stream of user-generated content). This is the first work to study the efficient maintenance of dense subgraphs under such streaming edge weight updates. For a wide range of definitions of density, we derive theoretical results regarding the magnitude of change that a single edge weight update can cause. Based on these, we propose a novel algorithm, DynDens, which outperforms adaptations of existing techniques to this setting and yields meaningful, intuitive results. Our approach is validated by a thorough experimental evaluation on large-scale real and synthetic datasets.     

Effect of scraped-surface tube cooler temperatures on the physical properties of palm oil margarine

The effects of scraped-surface tube cooler temperatures on the isothermal solid fat content (SFC) of palm oil margarine during processing and on margarine consistency (yield value, g/cm²), SFC, and polymorphic changes in storage were studied. SFC was measured in the mixing tank after leaving the tube cooler and the pin worker. The SFC at the tube cooler exit was proportional to the amount of cooling; a higher SFC was produced by more extreme cooling treatment. The SFC of all margarines were reduced in the pin worker, and the reduction was related to the initial SFC profile of palm oil. Margarine samples were stored at 28°C for 28 d and tested daily. Margarine processed at 25°C in the tube cooler had the highest consistency and the least change in SFC, but by the second week crystals had transformed into the β form. Uniform product consistency and SFC were observed in margarines processed at 20 and 15°C. These margarines retained the β′ crystal form for 3 and 4 wk, respectively. The best palm oil margarine was obtained with a tube cooler temperature of 15°C and a residence time of 1.8 min.     

Protein folding transition states: elicitation of Hammond effects by 2,2,2-trifluoroethanol

Adaptation of the techniques of classical physical-organic chemistry to the study of protein folding has led to our current detailed understanding of the transition states. Here, we have applied a series of structure--activity relationships to analyse the effects on protein folding transition states of 2,2,2-trifluoroethanol (TFE), a reagent that is usually assumed to act by stabilising secondary structure. The folding and unfolding of the highly alpha-helical tetramerisation domain of p53 provides a useful paradigm for analysing its effects on kinetics: The first step of its folding consists of an association reaction with little, if any, formation of secondary structure in the transition state; and the final step of the folding reaction involves just the formation of bonds at subunit interfaces, with the alpha-helical structure being completely formed. We have systematically measured the effects of TFE on two sets of structure--activity relationships. The first is for Phi values, which measure the degree of non-covalent bond formation at nearly every position in the transition state. The second is for relative effects of the denaturant, guanidinium chloride, on kinetics and equilibria, which measure the gross position of the transition state on the reaction co-ordinate. We find that TFE modulated the kinetics by a variety of effects other than that on secondary structure. In particular, there were Hammond effects, movement of the position of the transition state along the reaction co-ordinate, which either significantly speeded up or slowed down protein unfolding, depending on the particular mutant examined. The gross effects of TFE on protein folding kinetics are thus not a reliable guide to the structures of transition states.     

"SSR模式"在《空间信息技术导论》教学中的应用

分析了在网络技术广泛应用的背景下教与学的特点和面临的问题,结合<空间信息技术导论>课程的特点,阐述了在教学中应用"自学-讨论-科学研究"教学模式的具体做法.     

嗜酸氧化亚铁硫杆菌驯化条件的研究

随着办研究氧化亚铁硫杆菌结果表明,最佳培养温度为30℃左右,最佳生长pH为2.0～2.5,最佳生长初始Fe2＋浓为0115mol/L左右,在进行细菌培养时接种量取10%比较恰当。低pH值和高浓度Fe2＋驯化后,在培养温度30℃、初始pH值1.5、初始Fe2＋浓度25g/L条件下,氧化亚铁硫杆菌仍能保持一定的Fe2＋氧化活性,6天Fe2＋氧化率可达82.28%,Fe2＋平均氧化速率达3.43g/L/d,pH值的变化是先上升后下降,最后稳定在1.81。     

Temperature distribution and dynamic control of secondary cooling in slab continuous casting

To predict and optimize the temperature distribution of slab continuous casting in steady operational state, a three-dimensional model (named offline model) based on the heat transfer and solidification theories was developed. Both heat transfer and flux distribution characteristics of the nozzle sprays on the slab were considered, and the complicated boundary condi-tions, such as spray cooling, natural convection, thermal radiation as well as contact cooling of individual rolls were involved in the model. ...     

电信网安全防护中的信令防护技术

信令安全是电信网安全研究中的一个重要课题,总结了现有针对信令的主动防护与被动防护技术,提出了一种基于＂插入＂方式的信令防护技术,设计了2种不同的隐形接入方式,实现了在不需要对网络进行改造,也不改变现有网络拓扑与配置前提下的一种行之有效的信令防护的快速部署。     

脱硫石膏－粉煤灰活性掺合料设计及水化特性

针对电厂两大工业废渣--烟气脱硫石膏及粉煤灰,通过试验研发用于混凝土的活性复合矿物掺合料.以适当比例复合后的脱硫石膏及粉煤灰等量取代水泥掺入到水泥砂浆中,通过活性激发措施,以胶砂流动度、早期强度以及强度发展规律等作为控制指标探索脱硫石膏及粉煤灰的最优配比,同时通过微细观结构的SEM观测评价脱硫石膏-粉煤灰活性矿物掺合料在水泥基材料中的作用效应.结果表明,脱硫石膏及粉煤灰以1:2的比例复合等量取代水泥30%掺入水泥砂浆中,可获得较为优异的胶砂流动度、早期强度,而后期强度能赶上甚至超过基准水泥胶砂;SEM表明由于脱硫石膏及其它外加组分的活性激发效应,粉煤灰的活性得到有效激发,早期有明显的钙矾石生成.脱硫石膏-粉煤灰复合矿物掺合料的研发可大量消纳燃煤电厂的工业废渣,且在水泥基材料体系中具有优异的水化及低成本特性,具有显著的"绿色"效应,符合中国"可持续发展"的战略要求.     

企业安全生产事故隐患治理体系

安全生产领域事故隐患是由人的不安全行为、物的不安全状态、不良作业环境及安全管理缺陷4个方面因素综合作用造成的.笔者利用安全系统工程的方法,从企业安全生产可持续发展的角度,提出建立事故隐患治理体系的方法和方案,包括隐患排查、评估、分级、评价和整改,其对生产企业事故排查、隐患治理、隐患监管具有一定的现实意义.     

两种电子温度等离子体系统中的电子束流不稳定性

在一个包含两种不同温度电子的等离子系统中,用一维全粒子模拟模型研究电子束流不稳定性.在模拟模型中,考虑了离子与电子的实际质量比与将离子看成是静止不动的背景离子相比,在一维全粒子模拟中噪声要低,并且由于离子的原因电子束流不稳定性变弱.由于电子速度分布出现的平台和一维全粒子模拟模型中电子洞的形成使得孤波产生,在模拟中该孤波沿着电子束流的反方向传播.