ＶＲ/ＭＲ技術を用いた歴史観光のＩＴ活用に関する研究

観光の新しい形が求められている．わが国の経済を支える大きな産業の一つとして，観光業に大きな期待が集まっている．観光地の魅力を高めるために，観光資源を抱える各地の自治体では様々な模索を続けており，観光のIT 活用はその目玉となっている．インターネットを利用した観光案内は広く普及し，すでに多くの旅行者が使用する社会インフラとなっている．差別化のために新しい技術が積極的に試まれており，バーチャルリアリティ(VR)やミックストリアリティ(MR)はその一つである．観光の心理学的分析によれば，観光が動機づけ・学習・訪問・感動・再訪のサイクルで成り立つとされている．各段階をIT 活用によって魅力的にしようという提案がなされており，スマートツーリズム構想として知られている．とくに訪問先の現地の魅力をよりよく伝えて感動を深めるための手段が課題となっている．文化財をデジタルデータ化する技術はデジタルアーカイビングと呼ばれ，VR/MR 技術を用いてデジタル化された文化財を鑑賞する試みがなされており，感動深化のために観光への融合が標榜されている．本研究では，VR/MR を使ったデジタルアーカイブの展示の観光応用を試み，実用化へ向けた提案を行う．古代飛鳥京があった奈良県高市郡明日香村において，飛鳥時代を題材にして往時の建物や街並みをCG を用いて仮想復元したVR コンテンツを制作し用意した．遺跡が存在したとされる場所においてVR コンテンツを鑑賞できるように，屋外で使用できる歴史体験端末を開発し実証実験を行った．とくに観光応用における課題の一つが移動にあると見定めて，移動中にVR/MR コンテンツを楽しむことのできる運用を試みた．VR/MR の観光応用は実例が少ないため，大小さまざまな課題が残されている．そこで次の2 つの形式の運用を試みた．・ガイドツアーのサポートツールとしてモバイル型VR/MR 装置を用いる運用・多人数が同時に移動しながら体験できるMR モビリティシステムとしての運用観光イベントとして一般の訪問客から参加者を募り，体験終了後にアンケート調査の協力をお願いし，観光応用の可能性を調査した．その結果，VR/MR の観光応用の有用性と課題を確認できた．VR/MR を観光に導入する大きな目的は観光地の魅力を深めて観光客に現地に足を運んでもらうことであり，歴史観光体験の感動の深化をVR/MR技術で実現するための課題と要件を検討していく．VR/MR の観光応用に関する課題は，運用面における課題および技術面における課題の2 つの側面がある．運用面における課題は，環境を壊さない導入方法，従来のサービスを壊さない導入方法，現地における運用，コミュニケーションの促進，移動の有効活用が重要であると考え，2 つの試行の結果を基に解決方法の検討をおこなった．ガイドツアーのサポートツールとしてモバイル型VR/MR 装置を用いる運用では，特に運用者が現地のボランティアガイドであることに留意して，システムを受け入れてもらいやすいように近いしやすく使いやすいようにすることに配慮した．技術優先とせずに，従来の観光サービスを後押しするようにVR/MR システムを導入することが重要であると考える．技術面での課題は，現時点では特に音による臨場感の向上，VR/MR 特有のコンテンツ編集コストの削減手法が重要であると考えた．MR モビリティシステムを用いた運用において，移動に伴い場面が転換していくようなストーリー仕立ての演出を行うことでエンターテイメント性の向上が期待できる．観光においてエンターテイメント性は重要な要件の一つである．移動中のユーザーの位置・姿勢に伴って，映像とともに音も空間を持った表現にすると臨場感を向上できる．また，映像を360 度任意の方向に眺める自由が与えられている多くのMRシステムのようにユーザーの行動の自由の幅が広すぎると，コンテンツ制作者の意図とは合わずに体験者が視線を送っていない方向で演出されているイベントに気が付かないという問題がある．演出についても，音声により気配を感じさせることによって，ユーザーの視線方向を暗に誘導することができ，その幅を広げることができる．VR/MR のコンテンツ制作は，通常のCG やアニメーションコンテンツの制作と異なり，実際に存在した事物の復元をするためわずかな記録や現存する事物の情報を基にして，最大限史実に近い形で仮想復元する必要がある点に難しさがある．特に日本の古代建造物は多くが木造であり，災害等で失われ現存していないことが多い．しかしながら，礎石や石敷きなど石でできた構造物の一部は残されている史跡が多い．そこで，現存する石敷きの情報を基にして簡単な操作によって自然に石敷きの編集をできる手法を開発した．このようにデジタルアーカイブの情報の欠落部分を容易に自然に復元するための編集手法は今後重要になってくるだろう．電気通信大学201

Three-Dimensional Structural Analysis of Temple 16 and Rosalila at Copan Ruinas

Temple 16 is an ancient Maya structure located at the heart of the Copán Ruinas Acropolis in Western Honduras. Temple 16 contains several earlier structures within it that were built on top of each other throughout Copán’s history. One of these earlier structures, Rosalila, is one of the most culturally significant structures within the Acropolis due to its preservation. An intricate series of archeological tunnels have been excavated throughout Temple 16 to allow for its study. However, significant cracking has been observed within Rosalila and several tunnels have experienced partial collapse. This not only poses a life safety issue for those utilizing the tunnels, but also demonstrates the risk to invaluable cultural heritage. To this end, this thesis aims to provide a rigorous structural assessment of Temple 16 and the buried Rosalila structure, accounting for its complex 3D tunnel system, to understand the leading causes of tunnel collapse and structure deterioration. Geometric data was collected of the acropolis, Temple 16, Rosalila, and the complex network of tunnels using a combination of ground-based lidar and uncrewed aerial systems. The resulting point clouds were vectorized to yield a series of connected surfaces, which were then meshed as a solid to facilitate finite element analysis. Analyses were conducted to understand both the current stress distribution within Temple 16 as well as to study the impact of various hypothetical tunnel backfilling scenarios to provide recommendations for preservation and tunnel safety. The generated finite element models were analyzed under three water saturation levels to account for the impact of heavy rainy seasons and water infiltration on the stress levels of the tunnels. From the analyses, sixty-three highly stressed areas were identified among the current tunnel system, with most of them being close or directly underneath Rosalila. From the tested hypothetical backfilling scenarios, it was found that, backfilling excavated sections can improve or worsen these stress concentrations depending on the location of the tunnel within the system. Finally, by analyzing Rosalila’s current geometry, it was observed that the structure experiences high levels of stress on its southern side due to its location within Temple 16. From this, it was concluded that fixing exposed areas of Rosalila that were affected by excavation on its southern side can significantly alleviate the existing deterioration and improve the stress flow in these areas. Advisors: Christine E. Wittich & Richard L. Wood

Experimental and Numerical evaluation of mine pillar design

Mining is an art of extracting valuable minerals or other geological materials from the earth, usually from an ore body, vein or (coal) seam with minimum unit cost within acceptable social, legal, and regulatory constraints. There are two major methods of underground mining of coal: Bord& Pillar Method and Longwall Method. Pillars are mostly encountered in the former method. Pillar is the structural element and form an integral part of a mine on which the stability of the mine depends. A pillar support is intended to control rock mass displacement right through the zone of influence of mining, while mining activities proceeds. If pillars are made too small increasing the extraction percentage, it would affect the stability of the mine and vice-versa. An economic design of a support system implies that ore committed to pillar support be minimum, while fulfilling the vital requirements of assuring the global stability of the mine structure. This project critically studies the different optimum combination of pillar dimensions that could be effectively incorporated in the mines. Geotechnical factors of a nearby underground coal mine has been determined in the laboratory. Different approaches of pillar design have been compared. Variation of safety factors with width to height ratio of pillar, extraction percentage and depth of cover has been determined and conclusion has been made. The safety and feasibility of mining method is obtained through an optimum correlation between safety factor and extraction percentage. Numerical modeling has been done to evaluate the maximum stress induced over the pillar and gallery and also to calculate the deformation in the pillar and the sagging in gallery due to induced stress. ANSYS.13 3-D software was used in numerical modeling. Different mining parameters were changed to measure the effects on stress behavior, deformation and sagging in gallery

Stability Assessment of Salt Cavern Roof Beam for Compressed Air Energy Storage in South-Western Ontario

Due to the intermittent nature of renewable energy sources, application of energy storage systems is an important part of the development in support of clean technologies. Compressed Air Energy Storage (CAES) plants can provide utility scale storage by compressing air into a reservoir during off-peak period and generating electricity by expanding the air when energy demand is high. CAES is a proven technology that offers various services to the power network and provides flexible load management; however, site selection is a critical step during the design process of a plant. Salt deposits are recognized as potentially suitable geological layers for a compressed air energy storage system. In south-western Ontario, salt beds of the Salina Group of the Michigan basin provide suitable salt deposits for the excavation of storage caverns. Only two salt beds of the Salina Group are thick enough for excavation of a cavern, these are known as the unit A2 and unit B salt beds. In the case of an underground storage system, stability and serviceability of the storage cavern must be investigated using geomechanical models. Geomechanical issues may cause serious damage to the cavern, which could stop the system from functioning. The stability of the cavern roof layer has been investigated using voussoir beam theory. This method has been widely used to model rock mass behavior around underground openings. The results of the analytical solution have been validated against an existing case and verified by using a Universal Distinct Element Code (UDEC). The stress distribution within roof beams is investigated and upper and lower limits of roof size have been determined. Based on the findings from numerical analyses, assumptions of the voussoir method iv oversimplify the problem and cause inaccurate results. Hence, the selected iterative solution has been modified using a nonlinear approach. The updated procedure significantly enhanced the consistency of the results obtained from analytical solution with numerical models. To demonstrate validity of the modifications, a systematic parametric study has been included by using a wide range of beam parameters. The impact of creep behavior of the roof beam was examined by adding the deformation due to steady state creep to the elastic response of the beam. Also, the effect of the pressure difference around the cavern roof has been examined to determine maximum and minimum pressure inside the cavern with respect to size of the roof layer

ARCHITECTURE ESTIMATION FROM SPARSE IMAGES USING GRAMMATICAL SHAPE PRIORS FOR CULTURAL HERITAGE

The estimation and reconstruction of 3D architectural structures is of great in- terest in computer vision, as well as cultural heritage. This dissertation proposes a novel approach to solve the di??cult problem of estimating architectural structures from sparse images and e??ciently generating 3D models from estimation results for cultural heritage. This approach takes as input one plan drawing image and a few fac¸ade images, and provides as output the volumetric 3D models which represent the structures in the sparse images. Support of this research goal has motivated new investigations in underlying structure estimation problems including detecting structural feature points in 2D images, decomposing plan drawings into semantically meaningful shapes for medieval castles, estimating rectangular and Gothic fac¸ades using shape priors, and estimating complete 3D models for architectural structures using a novel volumetric shape grammar. Major outstanding challenges in each of these topic areas are addressed resulting in contributions to current state-of-the-art as it applied to these di??cult problems

Geotechnical Engineering for the Preservation of Monuments and Historic Sites III

The conservation of monuments and historic sites is one of the most challenging problems facing modern civilization. It involves, in inextricable patterns, factors belonging to different fields (cultural, humanistic, social, technical, economical, administrative) and the requirements of safety and use appear to be (or often are) in conflict with the respect of the integrity of the monuments. The complexity of the topic is such that a shared framework of reference is still lacking among art historians, architects, structural and geotechnical engineers. The complexity of the subject is such that a shared frame of reference is still lacking among art historians, architects, architectural and geotechnical engineers. And while there are exemplary cases of an integral approach to each building element with its static and architectural function, as a material witness to the culture and construction techniques of the original historical period, there are still examples of uncritical reliance on modern technology leading to the substitution from earlier structures to new ones, preserving only the iconic look of the original monument. Geotechnical Engineering for the Preservation of Monuments and Historic Sites III collects the contributions to the eponymous 3rd International ISSMGE TC301 Symposium (Naples, Italy, 22-24 June 2022). The papers cover a wide range of topics, which include: 　 - Principles of conservation, maintenance strategies, case histories - The knowledge: investigations and monitoring - Seismic risk, site effects, soil structure interaction - Effects of urban development and tunnelling on built heritage - Preservation of diffuse heritage: soil instability, subsidence, environmental damages The present volume aims at geotechnical engineers and academics involved in the preservation of monuments and historic sites worldwide

Proceedings of the 8th International Conference on Civil Engineering

This open access book is a collection of accepted papers from the 8th International Conference on Civil Engineering (ICCE2021). Researchers and engineers have discussed and presented around three major topics, i.e., construction and structural mechanics, building materials, and transportation and traffic. The content provide new ideas and practical experiences for both scientists and professionals