Crime prediction by data-driven Green’s function method

We develop an algorithm that forecasts cascading events, by employing a Green’s function scheme on the basis of the self-exciting point process model. This method is applied to open data of 10 types of crimes happened in Chicago. It shows a good prediction accuracy superior to or comparable to the standard methods which are the expectation–maximization method and prospective hotspot maps method. We find a cascade influence of the crimes that has a long-time, logarithmic tail; this result is consistent with an earlier study on burglaries. This long-tail feature cannot be reproduced by the other standard methods. In addition, a merit of the Green’s function method is the low computational cost in the case of high density of events and/or large amount of the training data.     

变频技术在数控机床上的应用

介绍了采用数控车床的主轴驱动中变频控制的系统结构与运行模式，并简述了无速度传感器的矢量变频器的基本应用。     

交错型PFC升压控制开关电源电路设计

本文分析和设计了一种基于飞思卡尔公司的MC56800/E为控制芯片的零电压ZVS准谐振开关模式电源。其前级采用功率因数校正(PFC)技术,后级采用全桥逆变、和全桥整流技术,并在高频开关变压器的一次侧采用准谐振软开关技术。实验结果表明,该电路达到了设计标准,有效提高了装置的能效。     

Initiation of business relationships in service-dominant settings

Industrial companies today are becoming increasingly service-oriented and therefore need to shift from selling hardware to valuing services and managing customer relationships. A new and particularly significant challenge for these companies is how to initiate relationships which is an issue that has received surprisingly limited scientific attention. The aim of this study is to develop a conceptualization that explores the dynamics in the relationship initiation process in service-dominant settings. Narratives from three sellers of professional services, augmented with narratives from a buyer's view, form the empirical basis of the study. The dynamics in the relationship initiation process are clarified with three new concepts: status, converter, and inhibitor. The paper concludes with implications of the new conceptualization and suggestions for future research.     

Performance of information criteria for selection of Hawkes process models of financial data

We test three common information criteria (IC) for selecting the order of a Hawkes process with an intensity kernel that can be expressed as a mixture of exponential terms. These processes find application in high-frequency financial data modelling. The information criteria are Akaike’s information criterion, the Bayesian information criterion and the Hannan–Quinn criterion. Since we work with simulated data, we are able to measure the performance of model selection by the success rate of the IC in selecting the model that was used to generate the data. In particular, we are interested in the relation between correct model selection and underlying sample size. The analysis includes realistic sample sizes and parameter sets from recent literature where parameters were estimated using empirical financial intra-day data. We compare our results to theoretical predictions and similar empirical findings on the asymptotic distribution of model selection for consistent and inconsistent IC.     

摄影表现手段探究--现代核磁共振成像技术在艺术摄影中运用的实验研究

摄影的形成是科技进步的结果，为了获取图片这一目的，人类投入大量精力，通过摄影手段创造了许多优秀作品。核磁共振这一技术的诞生让我们燃起对未知的探解，重新看待获取影像的途径。文章通过核磁拍摄果蔬实验形成的作品发现，所得画面色彩丰富、细部新奇、布局精美。与传统摄影方法相比较，其感染力更强。这种新的成像方法，尝试对新技术的捕捉，探索对影像和拍摄技术的创新，丰富了摄影手段，为后续更深的摄影创作提供了新的可能。     

自适应GTR比例驱动电路的分析研究

本文介绍为航空静止变流器中的直流变换器而研制的ＧＴＲ基极驱动电路。在研究了功率晶体管对基极驱动电路要求的基础上，提出了一种能适应功率管参数的离散性和进行自调节的新型比例驱动电路，并分析了这种新型驱动电路的工作原理和设计方法。     

A New Kind of Marketing: Creating Micro-Niches Using Resonance Marketing

ABSTRACT

Marketing has been dramatically changed by the Internet, the old rules do not apply. The Web allows companies to create products using micro-segmentation for target markets that are extremely small. Firms that want to be successful have to learn about resonance marketing. Resonance marketing used in conjunction with cause marketing and/or multicultural marketing can help a company find new market niches, charge premium prices. It can also be of great value to those interested in starting a small business.     

A model for interest rates with clustering effects

We propose a model for short-term rates driven by a self-exciting jump process to reproduce the clustering of shocks on the Euro overnight index average (EONIA). The key element of the model is the feedback effect between the absolute value of jumps and the intensity of their arrival process. In this setting, we obtain a closed-form solution for the characteristic function for interest rates and their integral. We introduce a class of equivalent measures under which the features of the process are preserved. We infer the prices of bonds and their dynamics under a risk-neutral measure. The question of derivatives pricing is developed under a forward measure, and a numerical algorithm is proposed to evaluate caplets and floorlets. The model is fitted to EONIA rates from 2004 to 2014 using a peaks-over-threshold procedure. From observation of swap curves over the same period, we filter the evolution of risk premiums for Brownian and jump components. Finally, we analyse the sensitivity of implied caplet volatility to parameters defining the level of self-excitation.     

从向导式旅游解说的受众与对象研究反思旅游教育现状

从旅游学术探究旅游解说系统主要涉及解说受众、解说对象、解说者、解说活动和解说语言等。旅游解说不仅对旅游经历、体验有着有效的作用，而且还是旅游区的一种有效管理工具。鉴于国外对其理论与实践皆十分重视，而我国研究相对薄弱，试图在国内理论研究中有所创新。欲通过对向导式旅游解说受众与对象的共振模型研究，对我国现行旅游教育给予有效的启示。