Extracting and analyzing semantic relatedness between cities using news articles   总被引：1，自引：0，他引：1  

Yingjie Hu  Xinyue Ye  Shih-Lung Shaw 《International journal of geographical information science》2017,31(12):2427-2451

News articles capture a variety of topics about our society. They reflect not only the socioeconomic activities that happened in our physical world, but also some of the cultures, human interests, and public concerns that exist only in the perceptions of people. Cities are frequently mentioned in news articles, and two or more cities may co-occur in the same article. Such co-occurrence often suggests certain relatedness between the mentioned cities, and the relatedness may be under different topics depending on the contents of the news articles. We consider the relatedness under different topics as semantic relatedness. By reading news articles, one can grasp the general semantic relatedness between cities; yet, given hundreds of thousands of news articles, it is very difficult, if not impossible, for anyone to manually read them. This paper proposes a computational framework which can ‘read’ a large number of news articles and extract the semantic relatedness between cities. This framework is based on a natural language processing model and employs a machine learning process to identify the main topics of news articles. We describe the overall structure of this framework and its individual modules, and then apply it to an experimental dataset with more than 500,000 news articles covering the top 100 US cities spanning a 10-year period. We perform exploratory visualizations of the extracted semantic relatedness under different topics and over multiple years. We also analyze the impact of geographic distance on semantic relatedness and find varied distance decay effects. The proposed framework can be used to support large-scale content analysis in city network research.  相似文献   

Structural geometry of the early Precambrian terrane south of Coimbatore in the “Palghat Gap”, southern India     

K. Naha  R. Srinivasan  G. K. Deb 《Journal of Earth System Science》1997,106(4):237-247

The ENE-plunging macroscopic folds, traced by calc gneiss interbanded with marble and sillimanite schist within the Peninsular Gneiss around Suganapuram in the ‘Palghat gap’ in southern India, represent structures of the second generation (D₂). They have folded the axial planes of a set of D₁ isoclinal folds on stratification coaxially, so that the mesoscopic D₁ folds range from reclined in the hinge zones, through inclined to upright in the limb zones of the D₂ folds. Orthogonal relation between stratification and axial planar cleavage, and ‘M’ shaped folds on layering locate the hinge zones of the D₁ folds, whereas folds on axial planar cleavage with ‘M’ shaped folds are the sites of the D₂ fold hinges. Extreme variation in the shapes of the isoclinal D₁ folds from class 1B through class 1C to nearly class 2 of Ramsay is a consequence of buckling followed by flattening on layers of widely varying viscosity contrast. The large ENE-trending structures in this supracrustal belt within the Peninsular Gneiss in the ‘Palghat gap’ could not have evolved by reorientation of NS-trending structures of the Dharwar tectonic province to the north by movement along the Moyar-Bhavani shear zone which marks the boundary between the two provinces. This is because the Moyar and Bhavani faults are steep dipping reverse faults with dominant dip-slip component. Deceased  相似文献   

A major seismogenic fault in a 'silent area': the Castrovillari fault (southern Apennines, Italy)     

F. R. Cinti  L. Cucci  D. Pantosti  G. D'Addezio  M. Meghraoui 《Geophysical Journal International》1997,130(3):595-605

Large historical earthquakes in Italy define a prominent gap in the Pollino region of the southern Apennines. Geomorphic and palaeoseismological investigations in this region show that the Castrovillari fault (CF) is a major seismogenic source that could potentially fill the southern part of this gap. The surface expression of the CF is a complex, 10–13 km long set of prominent scarps. Trenches across one scarp indicate that at least four surface-faulting earthquakes have occurred along the CF since Late Pleistocene time, each producing at least 1 m of vertical displacement. The length of the fault and the slip per event suggest M =6.5-7.0 for the palaeoearthquakes. Preliminary radiocarbon dating coupled with historical considerations imply that the most recent of these earthquakes occurred between 380 BC and 1200 AD, and probably soon after 760 AD; no evidence for this event has been found in the historical record. We estimate a minimum recurrence interval of 1170 years and a vertical slip rate of 0.2-0.5 mm yr^-1 for the CF, which indicates that the seismic behaviour of this fault is comparable to other major seismogenic faults of the central-southern Apennines. The lack of mention or the mislocation of the most recent event in the historical seismic memory of the Pollino region clearly shows that even in Italy, which has one of the longest historical records of seismicity, a seismic hazard assessment based solely on the historical record may not be completely reliable, and shows that geological investigations are critical for filling possible information gaps.  相似文献   

江苏常熟—太仓5.1级地震前兆异常的识别     

鲁宗良 《地震地磁观测与研究》1992,13(1):40-45

本文讨论了當熟—太仓5.1级地震前,邻近地区曾多次出现小震震群,形成一个空区之后,在黄海“老震区”出现相对的波形异常。研究结果表明,这些空区和波形异常的出现,除了与地质条件有关外,还显示了出现主震前兆异常的可能性。  相似文献   

澜沧—耿马地震前的地震活动条带与空区   总被引：1，自引：0，他引：1  

范杨 《地震研究》1991,14(2):122-126

1988年11月6日滇西南发生了澜沧7.6级、耿马7.2级强烈地震,两震相距70公里。本文分析了大震活动的条带与空区特征。这两次地震之前既有M≥4.5地震活动条带,又有M≥3.5地震空区,条带与空区相连接。空区是震前三年多开始出现,震前半年消失的;条带是前一年多时间内形成的,条带的迅速形成深入到空区之内,促使了空区的消失。澜沧7.6级地震发生在两个条带的交汇部位,也是条带的端部、空区的边缘;耿马7.2级地震则发生在空区之内。  相似文献   

四川省地震重点监视防御区未来地震潜势的研究     

闻学泽  陈农 《四川地震》1992,(1):1-25

本文通过历史地震及现今地震活动性的分析、活断层分段理论及地震空区理论的应用、地震平均复发间隔及复发条件概率的估算以及多学科专家综合评估方法的引入，对川西鲜水河－安宁河－则木河断裂和滇东小江断裂带（中－北段）上15个不同段落的地震潜势进行了深入的研究。进一步修正并重新圈绘出位于鲜水河－安宁河－则木河断裂带上的四川省地震重点监视防御区，其范围：北起道孚县的葛卡或者松林口一带，南至西昌市，沿鲜水河－安宁河－则木河主干断裂带展布，全长约350千米。按对未来地震震级估计的不同，该区可分成3段。第1段位于葛卡或松林口至康定之间，震级估计为7±1／4级；第2段位于康定与石棉之间，估计的震级是61／2±1／4；第3段位于石棉至西昌之间，震级估计为7－71／2。此外，研究结果还显示了小江断裂带上的新塘湾和寻甸一嵩明两个段落未来15年内强震发生的概率相对较高。  相似文献   

苏联斋桑7.3级地震前地震活动的某些特征     

白超英  曲延军 《内陆地震》1990,4(4):351-355

1990年6月14日苏联斋桑7.3级强震发生在重力异常梯度带的拐弯处;强震前存在明显的M_s≥3.5级地震围成的空区;空区走向为北西西向,与斋桑强震发震构造走向一致,长轴约170km。1990年2月14日4.0级地震可视为信号震。最后初步讨论了阿勒泰活动区的地震趋势。  相似文献   

Sensitivity Analysis of Air Gap Motion with Respect to Wind Load and Mooring System for Semi-Submersible Platform Design   总被引：1，自引：1，他引：0  

霍发力  聂焱  杨德庆  董刚  崔锦 《海洋工程》2016,(4):535-548

A design of semi-submersible platform is mainly based on the extreme response analysis due to the forces experienced by the components during lifetime. The external loads can induce the extreme air gap response and potential deck impact to the semi-submersible platform. It is important to predict air gap response of platforms accurately in order to check the strength of local structures which withstand the wave slamming due to negative air gap. The wind load cannot be simulated easily by model test in towing tank whereas it can be simulated accurately in wind tunnel test. Furthermore, full scale simulation of the mooring system in model test is still a tuff work especially the stiffness of the mooring system. Owing to the above mentioned problem, the model test results are not accurate enough for air gap evaluation. The aim of this paper is to present sensitivity analysis results of air gap motion with respect to the mooring system and wind load for the design of semi-submersible platform. Though the model test results are not suitable for the direct evaluation of air gap, they can be used as a good basis for tuning the radiation damping and viscous drag in numerical simulation. In the presented design example, a numerical model is tuned and validated by ANSYS AQWA based on the model test results with a simple 4 line symmetrical horizontal soft mooring system. According to the tuned numerical model, sensitivity analysis studies of air gap motion with respect to the mooring system and wind load are performed in time domain. Three mooring systems and five simulation cases about the presented platform are simulated based on the results of wind tunnel tests and sea-keeping tests. The sensitivity analysis results are valuable for the floating platform design.  相似文献   

基于Solr的空间数据语义搜索研究     

韩学仁  王青山  郭勇 《测绘与空间地理信息》2016,(2):104-107

随着互联网技术的飞速发展,基于网络地图的空间数据搜索成为人们获取空间信息的重要手段。文章分析了当前地图搜索的不足和瓶颈,阐述了其在处理空间语义方面的缺陷,提出了一种基于Solr的空间数据语义搜索方案:将全文检索引擎Solr应用到空间数据搜索中;同时,引入自然语言处理和本体技术,实现基于自然语言查询的空间数据语义搜索。最后建立原型系统进行验证,证明了该方案的可行性和有效性。  相似文献   

Exploration of spatiotemporal and semantic clusters of Twitter data using unsupervised neural networks     

Enrico Steiger  Bernd Resch  Alexander Zipf 《International journal of geographical information science》2016,30(9):1694-1716

ABSTRACT

The investigation of human activity patterns from location-based social networks like Twitter is an established approach of how to infer relationships and latent information that characterize urban structures. Researchers from various disciplines have performed geospatial analysis on social media data despite the data’s high dimensionality, complexity and heterogeneity. However, user-generated datasets are of multi-scale nature, which results in limited applicability of commonly known geospatial analysis methods. Therefore in this paper, we propose a geographic, hierarchical self-organizing map (Geo-H-SOM) to analyze geospatial, temporal and semantic characteristics of georeferenced tweets. The results of our method, which we validate in a case study, demonstrate the ability to explore, abstract and cluster high-dimensional geospatial and semantic information from crowdsourced data.  相似文献