VR and AR Restoration of Urban Heritage: A Virtual Platform Mediating Disagreement from Spatial Conflicts in Korea

This study sought to uncover (1) the disagreement of spatial conflict between urban heritage and surrounding urban structure using two case studies from Korea—the main gate of the royal palace (Gwanghwamun) and the urban park containing celebrity graves (Hyoch’ang Park)—and (2) whether digital heritage restoration may mediate spatial conflict. A historical literature review and field surveys were conducted, with three main findings. First, the place identity of Gwanghwamun and Hyoch’ang Park, rooted in the Josŏn Dynasty, was seriously damaged during the Japanese colonial period. Although there were national attempts to recover the place identities of these sites during the modern period, limitations existed. Second, the restoration of Gwanghwamun’s Wŏltae (podium) and the relocation of Ŭiyŏlsa (the shrine of Hyoch’ang Park), which involved spatial transformation based on heritage, emerged in conflict with their surrounding urban structures—we identify a spatial conflict between local residents and stakeholders’ memories and the histories of these sites. Third, Donŭimun (the west gate of the city wall of the Josŏn Dynasty) digital restoration is a case mediating the conflict by restoring a sense of place in a virtual space and activating the cultural memory of the public by showcasing properties.

Changes in the Townscape of Lampertszásza (Berehove/Beregszász) in the 13th–15th Centuries

Across the River Tisza, there lies a town, Berehove (hereinafter also referred to as Beregszász [Hu]), situated on the north-eastern edge of the Great Hungarian Plain with the wind swaying ears of wheat, on the flatlands surrounded by rustling oak forests, gold-sweating trachyte mountains, and rivers subsiding upon reaching the plain. It is a veritable fairy garden, a small piece of the realm that out foremother, Emese, dreamt of back in the day. Places, just as people, have their own destinies: they emerge, evolve, thrive, and then, if they are destined so, disappear from the stage of history. The very first mention of Berehove dates back to early 1063, recorded under the name Lamperti, as the estate of Prince Lampert, son of Béla I of Hungary. Prince Lampert founded the later town. At the time, a small settlement must have been situated here with the prince’s countryseat inhabited by the garrison and the household servants. Residents of the house were mostly the gamekeepers and huntsmen of Bereg Forest County. To fully uncover the past is not possible – at the very most, some attempts can be made at its reconstruction by drawing on contemporary sources and relying on archaeological research. The mediaeval layout of the settlement is known from the available sources and serves as a basis for the present study in its efforts to reconstruct the settlement image of the historical town centre and to find out why Lampertszásza did not embark on the path of the ‘classic, city wall/fortification’ type of settlement development. The parish church is the only building of the mediaeval townscape that has survived partially, which, however, provides us with indications about the contemporary buildings of the one-time reginal town and the related ‘block of church buildings’.

Microbial-Induced Carbonate Precipitation Improves Physical and Structural Properties of Nanjing Ancient City Walls

The preservation and restoration of heritage sites have always been of key focus in the field of cultural relics. Current restoration methods mainly involve physical or chemical techniques, which are in many cases intrusive, destructive, and irreversible. Hereby, we introduce a novel biological strategy (microbial-induced carbonate precipitation (MICP)) to repair natural and simulated surface cracks on six hundred years’ old wall bricks (part of the Nanjing City Min Dynasty ancient wall, China). X-ray micro computed tomography (X-ray micro-CT) was employed to non-destructively visualize the internal structure of the MICP-treated brick cubes. The results showed that MICP can effectively repair both natural and simulated cracks present on the brick’s surface. The compressive strength of the MICP-treated brick cubes was significantly higher than that of the untreated control cubes (33.56 ± 9.07 vs. 19.00 ± 1.98 kN, respectively). MICP significantly increased the softening coefficient and decreased the water absorption rate (p < 0.05), indicating that the water resistance of the wall bricks can be improved after treatment. The 3D images from X-ray micro-CT, a method that could non-destructively assess the internals of such cultural structures, showed that MICP can effectively repair ancient relics, promoting durability and limiting degradation without affecting the structure. X-ray diffraction analyses showed that MICP generates the same calcite form as that of original bricks, indicating that MICP filler is compatible with the ancient city wall brick. These findings are in line with the concept of contemporary heritage preservation.

Amersfoort’s city walls

The development of Amersfoort’s two city walls can be divided into five periods. The first city wall was built in the first period 1259-1379. Although Amersfoort had been granted a charter in 1259, construction of the wall did not commence until after a serious assault by troops from the duchy of Gelre (Geulders) in 1274. The defensive wall was made stronger on that side, probably in expectation of more attacks from that direction. Between 1380 and 1500 Gelre troops attacked Amersfoort on multiple occasions and offensive firepower increased. Interestingly, Amersfoort opted to build a second city wall rather than reinforcing the existing one, considerably increasing the size of the city in the process. However, the project proved difficult to finance, defend and maintain, most likely due to the stagnating economy. Instead of being demolished after the second wall was in place, the first wall was reinforced with abutting houses, thereby becoming a kind of rampart within a rampart. The new fortifications turned out to be ineffective and in 1501 the city council decided to demolish the first city wall. This freed up space for a second generation of wall houses, mostly built from reused stone and with their front elevation on the trajectory of the first wall, with the exception of the houses along Krankeledenstraat and the southern section of Breestraat. In this same period, up until 1644, there was an attempt to strengthen Amersfoort’s defences. Several fortification plans were drawn up, none of which was implemented in its entirety, most probably due to a lack of financial resources. The ramparts that were realized are concentrated in the south-west since in this period the possibility of a new Spanish incursion was greater than any threat from Gelre. In the third period, 1645-1828, the council’s approval of additional openings in the city wall marked the beginning of a gradual deterioration of the defensive works. They had always been a big budget item, yet they had not been particularly effective. Accordingly, the council decided to convert the fortifications into lucrative functions. The Davidsbolwerk, for example, was turned into a cemetery. The most extensive demolition probably started in 1778 when it was also decided to dismantle various outer and inner gates in the second city wall. By 1829 the fortifications had entirely lost their defensive function and the city council proposed converting the outer line into a green pathway encircling the city, which would have resulted in the disappearance of all remaining traces of the wall. However, this was averted in 1844 by a national ban on the demolition of fortifications and they were subsequently integrated with the walking route. City planners continued to submit applications for demolition but encountered fierce resistance from heritage organizations. In addition, many remnants avoided demolition because most urban expansion occurred outside the historical centre. This resulted in a concomitant shift in the economic focus so that the fortifications no longer needed to be sacrificed to industrial development. Towards the end of the nineteenth century, with appreciation for the heritage value of fortifications growing, money became available for their restoration and Amersfoort’s historical centre was declared a conservation area.

AN ANALYSIS METHOD OF THE AMOUNT OF BRICKS USED IN PUZHOU ANCIENT CITY WALL BASED ON SLAM

The calculation of the amount of bricks used in the area of falling-off is of great significance to the restoration of the ruins of ancient cities In order to support the digital restoration of the city wall of Puzhou Ancient City Site, this paper analyzed and calculated the amount of outer cladding brick of the city wall based on SLAM data. Firstly, the point cloud data of Puzhou city wall is obtained by SLAM technology. Secondly, the original point cloud is processed by Geomagic Studio software, and the area of the damaged area is accurately measured from the packaging model. Finally, based on the characteristics of brick masonry of ancient city walls, this paper estimates the amount of brick used in the area where the external wall of drum tower falls off, thus providing data support for the repair and maintenance of Puzhou ancient city.

A METHOD FOR MONITORING BULGE OF ANCIENT CITY WALL AFTER REPAIR

The ancient city wall is affected by factors such as environment and man-made factors, and the formed bulging disease is particularly prominent, and even caused irreversible damage to the ancient city wall. Therefore, the bulging monitoring after the repair of the city wall should be the top priority of the deformation monitoring of the city wall. This paper proposes a new plan for monitoring the bulge after the repair of the city wall. According to the point cloud data before the repair, the characteristic plane is fitted to determine the bulge range of the city wall, and then observation signs are placed on the surface of the repaired city wall at the corresponding location where the bulging deformation is severe. By using a total station to monitor the space coordinates of the observation signs, the deformations perpendicular to the wall can be obtained through coordinate conversion, and then the bulging of the repaired city wall can be determined. The actual application results show that this method can effectively monitor the swelling of the ancient city wall after the repair.