Heritage

A community without heritage is a community without identity. Preserving heritage is essential to the pride of any nation and through understanding and appreciating it, the future of a community is envisioned and sustained. In a global world, communities’ ways of life and artistic expression are in continuous danger of being diluted. Heritage provides communities a necessary cohesion, social learning and a cultural identity.

Heritage is a semantically laden term. Heritage is associated with everything

inherited by the community from the past which is deemed of value and significance and which can be passed onto next generations. Heritage has been classified into many categories [147, 203, 234]: the first higher level classification is between

natural heritage andcultural heritage.

The United Nations Educational, Scientific and Cultural Organisation (UNESCO) de- fines natural heritage as to involve“natural features, geological and physiographical formations and delineated areas that constitute the habitat of threatened species of animals and plants and natural sites of value from the point of view of science, conservation or natural beauty. It includes nature parks and reserves, zoos, aquaria and botanical gardens” [407].

On the other hand, cultural heritage is defined as:

“the legacy of physical artefacts and intangible attributes of a group or society that are inherited from past generations, maintained in the present and bestowed for the benefit of future generations”

UNESCO [406]

The second major classification of heritage is between tangible heritage and

intangible heritage. Tangible heritage include artefacts, monuments and buildings of archaeological, historical, technological or scientific significance while intangible heritage include oral history and traditions, folk life, dance, customs, religious ceremonies, music, fashion, languages, storytelling among many other activities that have no actual physical presence but nevertheless have significance [147].

A motivation for this work is that neither geographical locations nor device constraints should limit our access to cultural heritage. Unfortunately, there are many challenges to the access, promotion and preservation of heritage in all its forms. The following section discusses to some extent these major challenges.

1.1.1.1 Challenges and Dangers

There are constant dangers for preserving intangible heritage. Many traditions, languages [100], religious practices, folk customs among many others are facing extinction due to many reasons such as cultural hegemony, wars and conflicts and

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political oppression. An example can be given is that of the Syriac Aramaic language which is still spoken in very few villages in Syria and Iraq. The language was historically oppressed and now faces the danger of complete extinction [183]. Tangible heritage has a plethora of challenges of its own. Many are human-made while others are natural. Many artefacts are fragile and difficult to present to the public in museums. Earthquakes, floods, and fires are among the major natural challenges for the preservation of cultural heritage artefacts and monuments. Wars and conflicts, pollution, climate change, acid rain, day to day use and inappropriate handling of artefacts and monuments are among the major human- made challenges to preserve cultural heritage. There are also a set of challenges that are economical in nature such as the lack of funding that hinders the repairment of monuments, the uncontrolled urbanization where sizeable populations inhabit historical cities and the unchecked tourist development [13].

The world was shocked by the barbaric acts of destruction of thousands of precious Neo-Assyrian artefacts, shrines, old churches and mosques in Iraq and Syria by terrorist organisations [101]. Another painful example can be seen in the destruction of the 6th century Buddhas of Bamiyan in 2001 [438]. Even if we remove wars and conflicts out of the picture, many cultural heritage sites have serious problems with accessibility due to geographical barriers and disabilities. We should consider if digitisation can act as a social insurance policy for future generations when time, decay and destruction may remove the artefact but a digital surrogate can remain. In addition, there are real challenges that endanger physical artefacts inside museums [86] such as degradation from day to day use (i.e. wear and tear), and sensitivity to humidity and light conditions [296] which leads to artefacts’ deterioration, in addition, to sensitivity to fluctuations in temperatures [156]. Furthermore, museums often do not have sufficient exhibition space to show their large collections thus a large number of cultural heritage artefacts remain hidden and stored in archives while only a small percentage is shown to the public. For example, the Smithsonian collection alone constitutes more than 150 million artefacts/specimen with less than 2% on display to the public [380] and only 12% are actually prioritised for digitisation [379]. The question is can digital technologies help liberate the 98% from the shadows?

destruction from extreme weather conditions (hurricanes, tornadoes etc.), and from pollution driven problems such as global warming [156] and acid rain, in addition to serious damage from earthquakes, vandalism and wars and conflicts [13]. For example, the marble of many Greek historic monuments including the Acropolis has been unfortunately eroded by the acid rain [13].

In addition, collection based institutions such as zoos, aquariums, botanical gardens and natural history museums are becoming more concerned with conservation issues during the last four decades due to the accelerate rate of deterioration to the environment and the loss of a big variety of animal and plant species [273].

With such pressing challenges, digitisation provides a needed rescue. The follow- ing section discusses the importance of digitising heritage for preservation and dissemination purposes.

1.1.1.2 Heritage and the Digital Domain

The digitisation of a heritage artefact or a monument involves creating a digital surrogate representation of it. Digitisation makes artefacts available to cultural and digital heritage stakeholders such as scholars, historians, museum curators, and members of the community. There is a recent trend for democratising all the aspects involved in the digitisation and dissemination of digital heritage assets. A trend supported by many mobile applications [448], commodity cameras and phones and free open source software.

In the past, digitisation of heritage artefacts required specialist equipment and expertise, but nowadays it is as easy as using commonly available phones, cameras and freely available software. Digital heritage artefacts, sculptures and buildings are captured and digitally reconstructed through techniques such as Photogram- metry [338], 3D Scanning [55] often called laser scanning and topographical techniques [314].

Digital heritage artefacts and virtual reconstructions are used by scholars, profes- sionals in culture heritage, and museum curators to document museum artefacts, heritage sites and archaeological finds. They help facilitate the study of heritage material without being bound to physical access and temporal constraints. Digital reconstructions can restore lost heritage such as the example of the Buddhas of Bamiyan which were digitally reconstructed from images after their destruc-

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tion [438]. In addition, virtual spaces act in some respect as a valid surrogate of the actual physical space [200]. For this thesis, one aspect we are concerned with is the quality of service in the provision of such digital experiences.

In addition, digital technologies serve a role to engage the community and foster participation, and preserve local cultural heritage which is viewed to be at risk. 3D models and reconstructions can be effective in promoting useful discussions and dialogues concerning heritage significance and where users can engage with new and novel perspectives of the history of the area and local heritage.

However with all the benefits of digitisation, there are understandably many fears, concerns and even sometimes anathema from a part of the heritage research community when it comes to digitisation or simulation of heritage [438]. There is a concern that the real interpretation, meaning and context of the heritage material would be stripped away by the surrogate digital reconstruction. People would attribute a fake, inaccurate and sometimes misleading interpretation to the simulation. As a concrete example, the virtual reconstruction of the St Andrews Cathedral in OpenSim [298] created by the Open Virtual World research group which the author of this thesis is part of, might create the impression of authenticity while in actuality the reconstruction is nothing but a hypothesis of how the cathedral might have looked like in its pristine days based on historical, and architectural records.

Another concern raised usually by archaeologists is that 3D reconstructions could become “closed boxes” thus could not be evaluated adequately and scientifically. Furthermore, these reconstructions can be without any particular purpose and would focus more on sophisticated computer graphics and artistic beauty rather than on being useful tools to help solve particular scientific challenges [75].

These concerns are highly debatable as many consider simulations and digital duplications of authentic artefacts a stimulus to increase their fame and awareness in the public [438]. In this thesis, we are concerned only with the quality of service of such environments in heterogeneous devices such as phones and desktop platforms and not with their authenticity or the debate surrounding that.

Despite the benefits of digitisation in cultural heritage, it is by no mean a long term preservation solution nor is a substitute for preservation efforts from the dangers and challenges explained in Section 1.1.1.1.

Today there is a broader use of end devices such as tablets and phones. As of 2018, 19.1 exabyte of Internet traffic per month comes from mobile devices [389] and as of February 2019, total web traffic of mobile devices excluding tablets accounted for 47.96 % of web page views worldwide. Over 60% of mobile phone web page views comes from the Asia continent [390]. These statistics show how much these devices are becoming a daily reality in our life. In many countries around the world such as the USA, mobile usage superseded the usage of desktop personal computers when it comes to the number of web visits [401].

This shows that the penetration of mobile devices is getting higher with each year. People connect their phones to a myriad of network connections ranging from WiFi broadband, 4G, 3G to 2G especially in rural areas. This leads to a major concern of how to view and engage with digitised material on the web for people in rural areas or in places with average or low internet speed. The average Internet broadband speed in 2017 varied enormously across the globe with countries on one side of the spectrum such as Yemen with an average speed of just 0.31 Mbps and Niger with average speed of 0.83 Mbps and on the other side, countries benefiting from high average speeds such as Singapore with 60.39 Mbps and Sweden with 46 Mbps [239]. Figure 1.1 shows the average Internet broadband speed across the globe.

Figure 1.1: Map showing average World Internet Broadband speed [239]

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ability to deliver digital heritage. A person in rural areas of Inverness in Scotland, is interested and willing to engage with high-end digital heritage objects in a virtual museum in Athens as much as a person living in London. Same can be said about countries in Africa or Asia. There is a need for a system that could adapt the delivery of the content to the device and network situation thereby achieving the best possible user experience.

The central aim of this thesis is to provide a solution that achieves adaptivity for 3D Web content in Web-Based Virtual Museums across heterogeneous devices and network regimes while achieving the best possible user experience. The thesis investigates the Quality of Service (QoS) and Quality of Experience (QoE) of the 3D Web used in Digital Heritage (DH) applications, particularly in Web-Based Virtual Museums.

This research adopts an empirical-based approach as defined by Campbell and Stanley [68] aiming to further the understanding of cultural heritage stakeholders and computer scientists of the QoS and QoE of different 3D Web components through a set of experiments culminating in the design and development of Hannibal, a QoS & QoE aware adaptive engine implemented in a virtual museum context.

One of the trends in digital heritage is dedicated to the design and implementation of Virtual Museums (VMs) [167]. In order to define and understand what a“Virtual Museum” is, it is pertinent to formally define first what a“Museum” is.