Guide to Archaeostratigraphic Classification and Terminology: Definitions and Principles

Abstract

Recent developments in archaeological research have highlighted the need to build up a Guide to Archaeostratigraphic Classification and Terminology. Its preparation was undertaken by Workshop 2 (“Classification et Terminologie Archéostratigraphiques”) in the context of the International Geological Correlation Programme. The paper below is the first version of this Guide project; it is intended to propose some basic definitions and principles.     

The Implications of Policy Stability for Renewable Energy Innovation in the United States, 1974–2009

Government support and commitment are of particular importance for renewable energy technology innovation activities, which are highly contingent on policy and market uncertainty. The research focus of this article is to examine the relationship between policy stability in public resource allocation and policy outcomes in renewable energy technologies. With time‐series cross‐sectional analyses, we test effects of both the stability and magnitude of federal R&D expenditures on patent applications in five renewable energy sectors (i.e., solar, wind, hydropower, geothermal, and bioenergy) from 1974 to 2009. The findings show that technology innovation is affected by both the magnitude and stability of government financial commitment. Nevertheless, when industries perceive government support over longer time frames, the magnitude effect loses explanatory power to the stability effect. In addition to federal R&D expenditures, policies pertaining to technology commercialization and marketization are a critical determinant of innovation activities. This study demonstrates that incremental, predictable, and credible expenditures facilitate renewable energy technology development. Conversely, a boom‐bust cycle of resource support fails to translate policy goals into intended results.     

Performance evaluation of a multi-image 3D reconstruction software on a low-feature artefact

Nowadays, multi-image 3D reconstruction is an active research field and a number of commercial and free software tools have been already made available to the public. These provide methods for the 3D reconstruction of real world objects by matching feature points and retrieving depth information from a set of unordered digital images. This is achieved by exploiting computer vision algorithms such as Structure-From-Motion (SFM) and Dense Multi-View 3D Reconstruction (DMVR). In this work, we evaluate the performance of a low-cost commercial SFM–DMVR software by digitising a Cycladic woman figurine. Although the surface properties of the specific artefact are considered 3D laser scanner friendly, its almost featureless white-grey surface composes a challenging digitisation candidate for image based methodologies as no strong feature points are available. We quantify the quality of the 3D data produced by the SFM–DMVR software in relation to the data produced by a high accuracy 3D laser scanner in terms of surface deviation and topological errors. We question the applicability and efficiency of two digitisation pipelines (SFM–DMVR and laser scanner) in relation to hardware requirements, background knowledge and man-hours. This is achieved by producing a complete 3D digital replica of the Cycladic artefact by following both pipelines.     

3D model of the Can Sadurní cave

Graphic and metric information about the site and its environment and about the different structures and artefacts located are indispensable for the optimal management of an archaeological excavation. A Geographic Information System (GIS) proves useful in managing and analysing information and data obtained from different sources. Two techniques of data capture, Terrestrial Laser Scanning (TLS) and close range photogrammetry, are used to generate accurate and high-resolution 3D models of a cave, the silos and a combustion structure at the Can Sadurní site (Begues, NE Spain). This site is especially noteworthy on account of its complete stratigraphy of the Catalonian Holocene. The capture and processing of the photogrammetric and TLS data used to generate 3D models are discussed in detail. These models cannot be obtained by classic archaeological techniques since the record is made layer by layer, approximately one decimetre apart, with the result that the information between the layers is lost. Our findings highlight the potential of these techniques for obtaining accurate and photorealistic models that facilitate a complete analysis of the available information at an archaeological site.     

Mapping by matching: a computer vision-based approach to fast and accurate georeferencing of archaeological aerial photographs

To date, aerial archaeologists generally apply simple rectification procedures or more expensive and time-consuming orthorectification algorithms to correct their aerial photographs in varying degrees for geometrical deformations induced by the topographical relief, the tilt of the camera axis and the distortion of the optics. Irrespective of the method applied, the georeferencing of the images is commonly determined with ground control points, whose measurement and identification is a time-consuming operation and often limits certain images from being accurately georeferenced. Moreover, specialised software, certain photogrammetric skills, and experience are required. Thanks to the recent advances in the fields of computer vision and photogrammetry as well as the improvements in processing power, it is currently possible to generate orthophotos of large, almost randomly collected aerial photographs in a straightforward and nearly automatic way. This paper presents a computer vision-based approach that is complemented by proven photogrammetric principles to generate orthophotos from a range of uncalibrated oblique and vertical aerial frame images. In a first phase, the method uses algorithms that automatically compute the viewpoint of each photograph as well as a sparse 3D geometric representation of the scene that is imaged. Afterwards, dense reconstruction algorithms are applied to yield a three-dimensional surface model. After georeferencing this model, it can be used to create any kind of orthophoto out of the initial aerial views. To prove the benefits of this approach in comparison to the most common ways of georeferencing aerial imagery, several archaeological case studies are presented. Not only will they showcase the easy workflow and accuracy of the results, but they will also prove that this approach moves beyond current restrictions due to its applicability to datasets that were previously thought to be unsuited for convenient georeferencing.     

Landscapes of Desire in the Poetry of Vittorio Sereni

The article studies trasformismo (party-switching) in Italian regional councils, examining Lombardy, Emilia Romagna, Tuscany, and Puglia from 1970 to 2010. Although lato sensutrasformismo – enrollment in the mixed group and party switches among the electoral lists – also has empirical relevance at regional level, stricto sensutrasformismo – the transition from the majority to the opposition, or vice versa – was quantitatively negligible. In the transition from the first to the second phase of the Italian Republic (after 1994), the regional system was reorganized according to a government model in which there is a clear distinction between the roles of the majority and the opposition, by virtue of the direct election of presidents from 1995 onwards. Thus, the thesis formulated by Giovanni Sabbatucci is confirmed: trasformismo is a pattern of government from the ‘center’ of the political space, which is a very different option from the adversarial model of democracy which has emerged in the regions over the last two decades. As a result, this also seems to confirm the neo-institutionalistic thesis expressed by Robert D. Putnam in his classic Making Democracy Work: Civic Traditions in Modern Italy (1993), according to which ‘institutions shape politics’ and the behavior of its actors.     

Inherent Characteristics of 2D Alluvial Formations Subjected to In-Plane Motion

ABSTRACT

We investigate the inherent characteristics of 2D basins subjected to vertically propagating P-SV waves using the finite difference approach. The ratio of fundamental frequencies between an inhomogeneous basin (f₀) and its equivalent flat layers (f_h) is found to be a function of both its outer overall geometry and inner geometric formation. 2D resonance can occur in inhomogeneous basins under certain conditions, and the f₀/f_h can be used to demarcate deep from shallow basin behaviors. With other conditions remaining the same, changing a basin from homogeneity to inhomogeneity results in a lower f₀/f_h and makes 2D resonance less likely to occur.     

基于关节臂扫描的文物精细三维信息留取

基于关节臂和高清摄影进行重庆大足千手观音现状信息留取和精细三维重建具有现状的真实、完整记录,可为现场修复提供参考,为此,提出一种新的基于关节臂高精度扫描的文物精细三维信息获取方法,利用关节臂对文物进行扫描,获得高精度几何数据,在此基础上建立超精细三维建模,同时利用人工选取控制点来获取高分辨率影像。基于本方法所获得的精细三维信息可以用于三维统计、虚拟修复和变化检测等方面,为文物的现场保护修复工作提供科学依据,并为其他文物精细三维重建提供参考。最后以重庆大足石刻造像为例,验证了该方法的可行性与有效性。     

The Newport Medieval Ship,Wales, United Kingdom

The Newport Ship is the most substantial late medieval vessel excavated and recovered in Britain in recent years. It was abandoned after extensive salvage, possibly following attempts at repairs to the hull. More than 23 m of the clinker‐built ship were recovered, along with significant artefact and environmental assemblages. Finds point to strong Iberian connections during the active life of the ship, which arrived in Newport in the Severn Estuary, after the spring of AD 1468. The dismantling and recovery of the ship has enabled detailed recording using innovative 3D digital techniques and approaches to hypothetical reconstruction. Publication includes a digital archive hosted by the Archaeological Data Service, a substantial report and this article.     

The Policy Sciences of Social Media

Twitter, Facebook, and other social media are increasingly touted as platforms not merely for networks of friends and for private diversion, but as vehicles that allow ordinary people to enter and influence the many arenas of public life. On the surface, the disparate and shapeless population of “i‐reporters,” policy “tweeters,” and anonymous news web site “commentators” would appear to challenge the comparatively well‐defined cast of professional diplomats, journalists, and propagandists that Harold D. Lasswell identified as policy‐oriented communicators. However, to illuminate the roles and impacts of social media in politics and policymaking, insights from Lasswell's “science of communication” must be embedded in Lasswell's broader lessons on value assets and outcomes. A closer look at the so‐called democratizing functions of social media in politics reveals the influence of powerful intermediaries who filter and shape electronic communications. Lasswell's insights on the likelihood of increased collaboration among political elites and skilled, “modernizing intellectuals” anticipates contemporary instances of state actors who recruit skilled creators and users of social media—collaborations that may or may not advance experiments in democracy. Lasswell's decision process concept is deployed to discover social media's strengths and weaknesses for the practicing policy scientist.