Introduction

Author(s):  
Richard Neer

What conditions must be met, what has to be in place, for an artifact or a work of art to be visible as such? At some level the answer is simple: the lights must be on. Quickly, however, the issues become more complex and turn out to vary from discipline to discipline. Not everything is visible at every time, which means that not every research program can see the same things. Material conditions are certainly important, but so are perceptual capacities, technologies of visualization, protocols of classification, and a great deal more. Archaeology is, among other things, the science of making things visible. It does so by digging them out of the ground; what time has hidden, the archaeologist reveals. The discipline is, as a result, keenly attuned to the material conditions under which such visibility becomes possible. Those conditions can be institutional, practical, and technological—funding, permits, and tools, be they picks and shovels or ground penetrating radar. But the conditions that archaeology investigates can also be historical, in the sense that, even in the distant past, visibility was neither uniform nor given. Historical agents, no less than time, may do the work of concealment: burying things, hiding them, rendering them variously obscure. It follows that archaeologists excavate more than artifacts. Equally, they excavate the conditions of each artifact’s potential visibility: the material conditions under which entities in a past world could be conspicuous and obtrusive, or recede into an unremarkable background. In short, they excavate relations no less than things—hence, by extension, a potential stratification in who saw what and at what time. Art history, on the other hand, tends to take visibility for granted. Integral to the discipline is a vast infrastructure of imaging and autopsy, from ArtSTOR to high-quality printing to travel grants—all committed to what Michael Fried has called “the primordial convention” that pictures and sculptures are meant to be beheld. This commitment exceeds the requirements of empirical research: even the most thorough technical documentation and the most meticulous description will, by broad consensus, be no substitute for seeing the object with one’s own eyes.

2002 ◽  
Vol 27 (4) ◽  
pp. 25-32 ◽  
Author(s):  
Susan M. Allen

The Getty Research Institute (GRI) is one of four programs of the J. Paul Getty Trust, an international cultural and philanthropic institution devoted to the visual arts, all of which reside at the Getty Center situated high on a beautiful hilltop in Brentwood, California. (The other programs of the Getty Trust are the J. Paul Getty Museum, the Getty Conservation Institute, and the Getty Grant Program.) From the beginning it was understood that the GRI would develop a research program in the discipline of art history and more generally the humanities, and that a library would support its work. Since its founding the GRI has, in fact, developed a major library as one of its programs alongside those for scholars, publications, exhibitions and a multitude of lectures, workshops and symposia for scholars, students and the general public. What is now known as the Research Library at the GRI has grown to be a significant resource and this article focuses on its history, the building that houses it, its collections and databases, and access to them all.


Antiquity ◽  
2011 ◽  
Vol 85 (330) ◽  
pp. 1402-1417 ◽  
Author(s):  
Christopher Loveluck ◽  
Yossi Salmon

In this neat investigation of a harbour site, the authors show how much can be learnt by site survey — and by surface plotting and remote mapping in particular. Here the excavations are used to pilot the geophysics, rather than the other way round, and ground-penetrating radar is employed to show not just where features are, but their sequence and their current vulnerability. This exemplary project demonstrates how, in modern approaches to fieldwork, sites are to be studied rather than excavated, comprehended rather than stripped.


2014 ◽  
Vol 556-562 ◽  
pp. 2719-2722
Author(s):  
Cun Chang Qin ◽  
Hui Lin Zhou ◽  
Qi Ming Yu ◽  
Xi Yuan

The grout behind the lining segments have a powerful influence on the long-term basis in shield tunnel construction in gravel sand and round gravel layers. Grouting layer detection in the shield construction is important. Two aspects are usually be used to evaluate the effectiveness of the grout treatment, one is the thickness of the Grouting layer and the other is to determine the presence and distribution of any damage in grouting layer. This study reports on the applications of the ground penetrating radar (GPR) and associated work carried out on Nanchang Metro line 1, Jiangxi province of China. After raw data preprocessing the results of the radar image are used to evaluate the thickness and hidden trouble of the grout layer automatically.


2007 ◽  
Vol 7 (6) ◽  
pp. 755-763 ◽  
Author(s):  
M. Metwaly

Abstract. Low and non-metallic landmines are one of the most difficult subsurface targets to be detected using several geophysical techniques. Ground penetrating radar (GPR) performance at different field sites shows great success in detecting metallic landmines. However significant limitations are taking place in the case of low and non-metallic landmines. Electrical resistivity imaging (ERI) technique is tested to be an alternative or confirmation technique for detecting the metallic and non-metallic landmines in suspicious cleared areas. The electrical resistivity responses using forward modeling for metallic and non-metallic landmines buried in dry and wet environments utilizing the common electrode configurations have been achieved. Roughly all the utilized electrode arrays can establish the buried metallic and plastic mines correctly in dry and wet soil. The accuracy differs from one array to the other based on the relative resistivity contrast to the host soil and the subsurface distribution of current and potential lines as well as the amplitude of the noises in the data. The ERI technique proved to be fast and effective tool for detecting the non-metallic mines especially in the conductive environment whereas the performances of the other metal detector (MD) and GPR techniques show great limitation.


2021 ◽  
Author(s):  
Alexandre Lisboa Lago ◽  
Welitom Rodrigues Borges ◽  
José Sidney Barros ◽  
Elizângela de Sousa Amaral

Abstract The town of Teresina, in the state of Piauí, Brazil, presents a history of land sinking processes. Two sinking events deserve to be highlighted, the first occurred in 1999 at Simplício Mendes street and the other occurred on July 31, 2008, at Francisco Mendes street. In order to identify possible shallow caves and associated structures, the Geological Survey of Brazil/CPRM developed a Ground Penetrating Radar (GPR) study to verify the occurrence of reflection patterns characteristic of these dissolution structures. In the field, the team conducted GPR sections along streets with a history of collapse. The GPR results obtained with shielded antennas of 200MHz allowed the identification of old areas of collapse of the terrain, to a maximum depth of 3 meters. In addition, the results obtained by this study show the potential of applying the GPR method in the characterization of the subsoil of paved streets, making it possible to identify various layers: asphalt, actual pavement, subgrade pavement, soil, saprolite, and mixed material. The high clay content of the subsoil does not allow the GPR to investigate further depths in the research area. The interpretation of aeromagnetometric data shows that the occurrence of sinkholes is associated with magnetic lineaments mainly in the NW-SE direction and enhances the understanding of the structural framework of the study area.


Author(s):  
M. S. Sudakova ◽  
M. L. Vladov ◽  
M. R. Sadurtdinov

Within the ground penetrating radar bandwidth the medium is considered to be an ideal dielectric, which is not always true. Electromagnetic waves reflection coefficient conductivity dependence showed a significant role of the difference in conductivity in reflection strength. It was confirmed by physical modeling. Conductivity of geological media should be taken into account when solving direct and inverse problems, survey design planning, etc. Ground penetrating radar can be used to solve the problem of mapping of halocline or determine water contamination.


2017 ◽  
Vol 3 (1) ◽  
pp. 73-83
Author(s):  
Rahmayati Alindra ◽  
Heroe Wijanto ◽  
Koredianto Usman

Ground Penetrating Radar (GPR) adalah salah satu jenis radar yang digunakan untuk menyelidiki kondisi di bawah permukaan tanah tanpa harus menggali dan merusak tanah. Sistem GPR terdiri atas pengirim (transmitter), yaitu antena yang terhubung ke generator sinyal dan bagian penerima (receiver), yaitu antena yang terhubung ke LNA dan ADC yang kemudian terhubung ke unit pengolahan data hasil survey serta display sebagai tampilan output-nya dan post  processing untuk alat bantu mendapatkan informasi mengenai suatu objek. GPR bekerja dengan cara memancarkan gelombang elektromagnetik ke dalam tanah dan menerima sinyal yang dipantulkan oleh objek-objek di bawah permukaan tanah. Sinyal yang diterima kemudian diolah pada bagian signal processing dengan tujuan untuk menghasilkan gambaran kondisi di bawah permukaan tanah yang dapat dengan mudah dibaca dan diinterpretasikan oleh user. Signal processing sendiri terdiri dari beberapa tahap yaitu A-Scan yang meliputi perbaikan sinyal dan pendektesian objek satu dimensi, B-Scan untuk pemrosesan data dua dimensi  dan C-Scan untuk pemrosesan data tiga dimensi. Metode yang digunakan pada pemrosesan B-Scan salah satunya adalah dengan  teknik pemrosesan citra. Dengan pemrosesan citra, data survey B-scan diolah untuk didapatkan informasi mengenai objek. Pada penelitian ini, diterapkan teori gradien garis pada pemrosesan citra B-scan untuk menentukan bentuk dua dimensi dari objek bawah tanah yaitu persegi, segitiga atau lingkaran. 


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