How not to build a world wireless network: German–British rivalry and visions of global communications in the early twentieth century

Abstract

Edward Snowden’s revelations laid bare an unprecedented scale of state influence on communications technology. But government elites have frequently shaped technological development through their beliefs about potentially nefarious uses of communications. This article argues that beliefs about how other states or groups might use a technology can shape innovation. In particular, German visions about the British use of cables spurred German investment in developing wireless telegraphy. Germans imagined that the British were using cable technology to damage Germany’s reputation, spy on Germany and ‘poison’ neutral countries against the Central Powers. The German government and military at first created a colonial wireless network to bypass British cables. In World War I, however, they sought to establish a world wireless network. In the end, innovation was significantly shaped by how Germans imagined their enemies’ uses of communications technology.     

Marconi,masculinity and the heroic age of science: wireless telegraphy at the British Association meeting at Dover in 1899

Abstract

In September 1899, at the annual meeting of the British Association for the Advancement of Science (BAAS) in Dover, Guglielmo Marconi’s wireless telegraphy system was used to transmit messages across the English Channel (and across a national border) for the first time. This achievement represented a highly effective performance of scientific masculinity and constitutes a key turning point in an important struggle between competing interpretations of invention and innovation as masculine practices within British science. The British Association tended to favor a narrative of scientific research as a collectivist, international, gentlemanly-amateur pursuit, largely confined to the laboratory. Marconi, by contrast, explained the development of wireless telegraphy as the achievement of his own genius. Appealing not only to the established scientific elite but to a range of non-traditional audiences, and stressing the possibilities or ‘imagined uses’ of his technology even more so than his actual results, he succeeded in commanding unprecedented influence.     

基于物联网技术的博物馆室内环境监测

物联网是传感器技术、无线通信技术、网络和嵌入式计算机技术交叉渗透的产物,随着物联网概念的提出,其技术得到了飞速发展,并且在社会多个领域取得了成功应用。针对当前博物馆环境监测存在的问题与难点,提出了基于物联网技术的博物馆室内环境监测系统的总体设计方案,在此基础上,分别给出了传感器节点、汇聚节点的软硬件设计方案,该设计具有低功耗、低成本、扩展灵活等优点。构建的测试平台验证了该系统良好的可行性与稳定性。     

南京市对外交通节点与酒店之间游客流动空间特征分析

利用旅游攻略数据,构建关系网络,探讨南京市对外交通节点与酒店之间游客流动这一特殊旅游流的空间特征,研究表明:1在节点方面,酒店的流入度、流出度和中心度均呈现出较为明显的圈层结构,高数值区域分布在城市中心的南北两端,外围区域数值较低,游客选择的酒店集中于夫子庙街道、健康路街道、梅园新村街道、玄武门街道;对外交通节点中,南京火车站中心度最高,铁路在南京旅游对外交通中作用突出。2在网络方面,随着流量阀值增加,整个网络的连通性不断增强,且流量分布更加均衡;核心对外交通节点与酒店集中分布街道在整个网络中起着重要的支配作用。3游客选择酒店并非集聚在对外交通节点周边,距离在酒店选择中所起作用不强,而与景点空间分布存在较强相关性。     

Life on horseback: palaeopathology of two Scythian skeletons from Alexandropol,Ukraine

In 2006, two skeletons were analysed that were previously excavated from the periphery of a Scythian burial mound, near the village of Alexandropol in southern Ukraine. Dated to ca. 325 BC, both remains are male. The first is that of a youth in his late teens who exhibits indications of biological stress and degenerative changes to the spine in the form of a Schmorl's node. The second is a middle‐aged individual with extensive healed lesions due to trauma to the right humerus and clavicle with associated bony changes of the elbow and spine. Stable isotope analyses indicate a diet based on C3 plants. Their skeletons suggest a rigorous life on horseback. Both may have served as sacrificial victims. Historical records document the strangulation of attendants and their placement around the periphery of royal burial mounds. Grave goods suggest that both were warriors, although the youth lacks the traumatic injuries exhibited by the older male. The individuals from Alexandropol may have served a Scythian king in life and in death. Copyright © 2008 John Wiley & Sons, Ltd.     

ON THE OPTIMAL LOCATION OF SENSORS IN MULTI-STOREYED BUILDINGS

A new approach has been developed for finding optimal location of sensors in 3D multi-storeyed buildings. This approach is based on the compact probabilistic representation of acceleration response in terms of its covariance matrix. For a specified number of sensors, the optimal location has been taken to be the one for which the computed covariance matrix is closest to the exact covariance matrix of the random field constituted by the acceleration response process. It has been found that the determined sensor locations match favourably with those predicted by earlier studies for the special case of shear buildings. Further, the optimality of the determined sensor locations has also been verified by identifying the system parameters from the time series data and comparing them with those of the Finite Element Model.     

Integrating Multi‐Sensor Remote Sensing Data for Land Use/Cover Mapping in a Tropical Mountainous Area in Northern Thailand

Accurate mapping of land use/cover conditions provides essential information for managing natural resources and is critical for further examination of land use/cover change and its subsequent impacts on the environment. Remote sensing offers a means of acquiring land use/cover data in a timely manner, with optical remote sensing images commonly being used in land use/cover related studies. The persistent cloud cover during the rainy season in Southeast Asia, however, presents a challenge for using optical images in land use/cover mapping. Integrating multi‐sensor images of different spectral domains is thus desirable because more information can be extracted to improve the mapping accuracy. The purpose of this study is to assess the potential of using multi‐sensor data sets for land use/cover mapping in a tropical mountainous area in northern Thailand. Optical data from Landsat Thematic Mapper, radar images from Advanced Land Observing Satellite/Phased Array type L‐band Synthetic Aperture Radar (PALSAR), and topographical data were used, providing complementary information on land use/cover. Classification and accuracy assessment were conducted for 12 different combinations of the data sets. The results suggested that short crop mapping using multi‐temporal Phased Array type L‐band Synthetic Aperture Radar images offered insights into the distributions of crop and paddy fields. Because of the mountainous environment of the study area, combining topographic data of elevation and slope into the classification greatly reduced the confusion between different land use/cover types. Improvement of classification accuracy was evident especially in separating evergreen and deciduous forests from other vegetation types and discriminating urban village and the fallow field classes.     

Potential of satellite based sensors for studying distribution of archaeological sites along palaeo channels: Harappan sites a case study

A large number of remote sensing based studies have shown evidence of a prominent river system, which has become buried under sand cover of Thar Desert sometime during late Holocene. This major river has been identified as Sarasvati, a legendary river mentioned in ancient Indian texts. This region is rich with archaeological sites of Harappan civilization (2500–500 BC). The present study has utilised digital image processing and enhancements techniques on multisensor satellite data followed by field investigations to reconfirm known traces and detect hitherto unknown traces of palaeochannels of Sarasvati river through parts of Indus alluvial plain in Thar desert. Potentials of IRS-P4 OCM (Primarily an Ocean Color Sensor, with eight narrow spectral channels, high radiometric resolution of 12 bits and large swath of 1420 m) could be exploited for the first time to detect hitherto unknown traces of palaeochannels of Sarasvati river through sand dune topography of Thar desert in parts of Western Rajasthan in India and adjoining parts of Pakistan by applying Principal Component Analysis technique. Pattern of palaochannels indicate westward migration of the Sarasvati river in parts of Indus alluvial plain. Database of more than 1000 archaeological sites compiled from various published sources, prepared in GIS environment could be utilised to understand their relationship with identified courses of the Sarasvati palaeochannels. Through this study it was found that there is a large spread of Mature Harappan (2200–1700 BC) sites along the palaeochannel of the Sarasvati and its tributaries in north-west India, but late Harappan (1700–1500 BC) sites are limited to further west in adjoining regions of Pakistan indicating that the shift of cluster of settlements have followed the pattern of river migration towards west. Digital terrain modelling by superimposing archaeological sites on SRTM DEM along with draped satellite data (Resourcesat-1 AWiFS and IRS-1D LISS-III) has helped in identifying geomorphological guides for archaeological investigations such as presence of relict natural levees seen as raised mounds and coincidence of known archaeological sites over them. It is suggested that other relict natural levees or raised mounds adjoining the identified palaochannel courses may be taken up for further archaeological exploration.     

低功耗、长时效、可靠传输的无线传感器  网络技术现状及进展

无线传感器网络技术作为物联网关键技术之一,得到了很多研究团队和行业应用的关注。无线传感器网络节点大多采用的电池供电,能量供应有限。因此,如何能减少节点的能量损耗使网络能够长时效稳定的工作,是无线传感网络在行业实际应用中需要解决的关键技术问题。本研究从低功耗、长时效和可靠传输三方面对传感器网络技术进行阐述,并对现有W SN实现低功耗、长时效、可靠传输的技术进行分类。