Multi-Criteria Decision-Making Framework for Evaluating Historic Sites in Huai’an Ancient Cities

Abstract

The preservation and restoration of historic sites is of great significance to the continuation of a city’s historical heritage and high-quality development. However, the conservation management of historic sites is still in the stage of exploration and improvement. The current states of development and preservation have been facing many problems, such as fragmented and poor states of preservation. It is crucial to retain and revitalize the authenticity of historic sites. A multi-criteria decision-making approach to an innovative evaluation model is proposed. Based on the cultural, social, and economic characteristics of the historical sites, an evaluation index system is constructed and weighted to judge its importance. The results suggest that the statuses of the historic relics at the facet layer have the most significant effect on the preservation of the authenticity of historic sites. The completeness of historic relics ranks first in weight among the evaluation indexes, which suggests that emphasis should be not only on their protection, but also on the preservation of their overall styles. The results will enable urban decision makers to effectively set the priorities of preservation and restoration by regions and stages. Huai’an, a major ancient city along the Beijing–Hangzhou Grand Canal in China, was taken as an empirical case study to validate the feasibility of the evaluation index system and its ability to provide references for the preservation and restoration of historic sites.

1. Introduction

Many national or world heritage sites of historical significance were constructed under economic, social, or religious influences [1,2,3]. Such sites of historical, social, economic, cultural, and aesthetic value deserve to be preserved [4,5]. Contemporary cities face a series of social, economic, and ecological problems. The preservation and restoration of historic sites constitute an important part of the sustainable development of the cities [6,7]. The United Nations Educational, Scientific and Cultural Organization (UNESCO) has adopted a principle of integrity in the preservation of historic sites by integrating the goal of urban heritage preservation with social and economic development [8,9,10]. In China, the current state of the development and preservation of historic sites is facing many problems, such as fragmented preservation, as well as a lack of systematic coordination and specific guidance in implementation [11,12]. In general, historic sites are large in number, small in scale, and scattered in distribution, thus presenting a fragmentation of delineation, which is not conducive to their preservation but also poses difficulties for their management. Historic sites are inferior to historical and cultural blocks in terms of the overall effects of repair and construction control. This is unfavorable for the long-term development and effective utilization of the sites.

This paper explores the factors influencing the preservation and restoration of historic sites, then presents a system for the evaluation of these factors and the multi-dimensional values of the sites. The system can provide a scientific basis for their preservation and restoration. The Beijing–Hangzhou Grand Canal is one of the three major ancient canals in the World. Starting from Hangzhou in the south, it passes by Suzhou, Changzhou, Huai’an, and many other cities before reaching Beijing in the north. Cities such as Hangzhou and Beijing have been extensively studied, but Huai’an requires further attention. Thus, it was selected as a case study for the topic of this paper. The historic sites in Huai’an Ancient City accurately reflect traditional patterns, urban textures, and environmental styles. Thus, they should be preserved and restored because of the great magnitude of their long-standing architecture, streets, watercourses, and other historical and cultural resources.

The remainder of this paper is organized as follows. Section 2 is a review of the literature concerning the background and preservation of historic sites. Section 3 introduces the research objects and methods. Section 4 analyzes the evaluation index system and its validation by an empirical study of three historic sites. Chapter 5 presents the conclusions.

2. Literature Review

2.1. Historic Sites

The term “historic site” can be traced back to The Venice Charter in 1964, which defines historic sites as areas around cultural relics and stresses the importance of their preservation [13,14,15]. The Charter stresses that cultural relics should be considered as a means for the restoration of original historic sites, so appropriate means of expression should be selected. With the rise of “cultural consciousness”, scholars such as Foucault and Derrida began to criticize the modern mechanistic and reductionistic worldview, the limitations of which have gradually become commonly understood [16]. This change in consciousness has shifted views of the preservation of historic sites from rigid mechanisms to respect for cultural and heritage diversity. In 1933, The Athens Charter defines a historic site as an area composed of architectural complexes with historical and cultural heritage [17,18]. In 1987, The Washington Charter enriched the connotations of this definition [19,20] by stating that historic sites are areas with historical significance in towns and cities, including time-honored urban centers and other areas that have retained their historical styles. The concept of historic sites relies on a recognition of the value of the integrity of built-up environments. This recognition has extended to an emphasis on historical and cultural values.

In 2005, the Chinese Code for the Preservation of Historical and Cultural Cities defines historic sites as areas of a certain scale that have retained a rich variety of cultural relics, remains, and architecture. These characteristics should truly reflect the ethnic or local features and traditional styles of specific historical periods [21]. Announcing the second batch of national historical and cultural cities in 1986, the State Council defined historic sites as blocks, architectural complexes, towns, and villages that have relatively concentrated distributions of cultural relics and historic sites that fully reflect the ethnic or local features and traditional styles of specific historical periods [22,23]. In sum, there are three specific criteria for a site to be regarded as historic: complete historical styles, authentic historical remains, and a certain scale and basic consistency in style within the field of view.

2.2. Research on Historic Sites

There are several reasons for the degradation of historic sites. First, exposure to natural or human hazards leads to their deterioration, and even destruction. Second, wars cause the destruction of historic sites in cities. Third, the rapid development of cities threatens to confine, or even replace historic sites with modern structures [1]. Therefore, the preservation and renewal of historic sites have become important issues. Studies on historic sites have gradually extended from single historical constructions to historic sites and their surroundings, thereby presenting a trend of gradual expansion from points to surfaces and stressing the importance of these sites and their economic and social environments. The preservation and restoration of historic sites are expounded in this paper from the perspectives of theory and practice.

A.

Theory of preservation and restoration of historic sites

Theories about the preservation of historic sites in Western countries have roughly gone through four stages. During the large-scale social transformation of the Industrial Revolution that began in the 18th century, there was a weak social consciousness regarding the preservation of historic sites, so no theory of targeted preservation was formulated. In the 19th century, urban renewal emerged as a response to urban decay and adjustment of renewal modes due to the Industrial Revolution [24]. In the 20th century, a trend of progressive renewal and sustainable development drove a series of worldwide regulations and constitutions, as well as bore a range of theories, such as “organic renewal”, “preservation of integrity”, and “continuous renovation” [25]. In the 21st century, the diversification of sustainable renewal theories, such as “urban healing” and “urban regeneration”, has shifted the preservation of historic sites from simply controlled preservation to a focus on the revival and strengthening of historic site functions [26]. Chinese scholars started their research on historic sites later than Western scholars, but followed similar paths. In 1961, the State Council promulgated the Provisional Regulations on Protection and Administration of Cultural Relics to establish a system of major protected cultural relics and sites. With the development of urbanization, the preservation of historic sites received more attention. Numerous theories about the preservation and restoration of historic sites have emerged. Among these theories is the “organic restoration” theory by Wu [27], the “self-organization model”, the “urban catalyst theory”, the “organic micro-circulation restoration model”, the “small-scale progressive model”, and the “environmental micro-restoration model” [28,29]. Theories about the preservation and renewal of historic sites have appeared with their bases on the statuses and characteristics of historic sites in specific periods, so classifications should be made with a view to the specific stage of research on preservation and renewal for solving related problems in more effective and targeted manners.

B.

Practice of preservation and restoration of historic sites

The preservation and restoration of historic sites vary across different countries. France introduced The Malraux Art in 1962. As the first country in the world to enact a modern law on heritage preservation, it has accumulated rich experience in the preservation and restoration of historic sites [30]. France strongly emphasizes protecting historic sites from destruction by modern urban construction while preserving and developing them, as well as other sites of significant cultural heritage. In 1967, the United Kingdom released the Civic Amenities Act, which stipulates that areas of special architectural, artistic, and historical value are protected [31,32]. In particular, special attention should be paid to keeping intact areas with architecture of special value and historical significance. Western countries tend to emphasize the integrity and authenticity of historic sites and the continuity of life.

Related scholars have also investigated the preservation and restoration of historic sites with regard to social management, planning methods, application of new technologies, etc. [33,34,35]. In terms of social management, the urban renewal plans of the United States, France, and Germany in the early 1960s emphasized the “theory of public participation” and laid foundations for such participation in the preservation of historic sites. Paul Davidoff proposed “Advocacy Planning” [36]. In 1969, Arnstein put forward the theory of the “civic engagement ladder” [37] and argued that the public should actively participate [38]. In terms of planning methods, regenerative design and joint design methods have been recently widely embraced [26]. Regenerative design is mainly employed to achieve environmental resilience and reduce the damage caused by natural disasters and human activities. New methods for the preservation and renewal of historic sites are frequently being introduced.

Overall, the academic community has a relatively mature understanding of the theory and practice of the preservation and restoration of a historic site. Theories are based on the status and characteristics of its historic period. In practice, there is the mode of physical style renovation based on urban planning and block revitalization with a view to residential and commercial functions. The purpose is to enhance economic vitality while retaining the forms of the site. Studies have focused on heritage preservation, physical environment improvement, tourism development, and social problems. There has been a transition from outward appearances to the inner essence in following the organic circulation levels of “physical spaces, cultural factors, and material economy”. Micro-factors are supplemented in the evaluation system and the evaluation factors for the preservation and renewal of historic sites are classified into three types: statuses of historic relics, basic environmental conditions, and degree of tourism development. In response to the lack of a simple quantitative method in urban planning decision making, this paper proposes a suitable one.

2.3. Determination of Evaluation Indexes

Firstly, the core issues of historic sites are identified by explanations of the underlying concepts, such as historical relics, historical architecture, surrounding environmental quality, cultural values, traditional styles, and local characteristics. Secondly, existing evaluation indexes for the preservation and renewal of historic sites are assembled from the literature review. The indexes mainly concern surrounding environments, historical architecture, tourism functions, supporting social amenities, ecological environments, commercial development, and public satisfaction [39]. The core issues related to the preservation and restoration of historic sites are based on a preliminary interpretation focusing on three facets: statuses of historic relics, basic environmental conditions, and degree of tourism development, as detailed in

Table 1. Core issues related to the preservation and restoration of historic sites.

Core Issues	Key Contents
Statuses of historic relics	Preservation: In the first half of the 20th century, theories about preservation and restoration, such as “organic restoration”, “preservation of integrity”, and “continuous renovation”, emerged [40,41,42].
	Renovation: France has taken a gradual approach through the macro-, meso-, and micro-levels to provide an operable basis for the style renovation of historic sites. The United States preserves the historical styles of cities through urban design. The UK has adopted “theme planning” and “action area planning” to improve the architecture, environments, transportation, and landscapes of historic sites [43,44,45].
Basic environmental conditions	Physical spaces: to improve the living conditions of inhabitants, as well as solve urban congestion and other problems. Residential orientation means that the material revival of a historical block prioritizes the residential functions, but also gives due consideration to other functions [46,47,48].
	Social problems, such as residential space differentiation and urban poverty, have been addressed through the active improvement of the living conditions of vulnerable groups around the world, such as the North Village (South Korea), Brindley of Birmingham (UK), and the Heiksch Community (Germany) [49,50,51].
Degree of tourism development	The preservation and maintenance of historic sites alone cannot give full play to their historical and cultural value. One effective way to bring their value into play is tourism development based on their heritage resources. The Castlefield Block of Manchester, England, has developed cultural and tourism industries based on local featured architecture and industrial landscapes, thus converting the historic site into a new highlight of the city [52,53,54].

.

An evaluation index system of influencing factors based on these core issues can be constructed on the principles of scientificity, comprehensiveness, and representativeness of the statuses of historic relics, basic environmental conditions, and degree of tourism development. The main indexes have been drawn from the green building evaluation system [55,56], the historic site and public space livability evaluation system [57,58], the historic site public satisfaction evaluation system [59,60], and the spatial vitality evaluation system [61,62]. The evaluation index system has been supplemented by on-site observations and expert interviews. A literature review has uncovered three evaluation facets and nine evaluation indexes, which are detailed in

Table 2. Evaluation indexes for the preservation and restoration of historic sites.

Evaluation Facet	Evaluation Index	Description
D1: Statuses of historic relics	C1: Completeness of historic relics	Integrity of architectural styles and the degree of retention of street spaces [40,41].
	C2: Harmonization with surroundings	Harmonization of architectural forms and the degree of integration with the new city [63,64].
	C3: Innovation degrees of transformation and utilization	Use of modern techniques and languages for the upgrading and innovation of traditional architectural spaces, thereby meeting the needs of modern people [65,66].
D2: Basic environmental conditions	C4: Convenience of transportation	Organization, supporting services, accessibility, and continuity of transportation. The transportation supporting services include parking lots, safe passage, sidewalks, road greening, and so on [67,68].
	C5: Living conditions of inhabitants	Adherence to the people-oriented principle to safeguard the interests of the inhabitants and minimize adverse effects [48,69].
	C6: Comfort degrees of public spaces	Landscape architecture, service facilities, ecological environments, etc. [70,71].
D3: Degree of tourismdevelopment	C7: Sightseeing and tourism	Experience of cultural landscapes, the cultural inheritance of historic sites, etc. [53,72].
	C8: Dining and shopping	Transformation of houses into commercial storefronts through spatial replacements, thereby accommodating the needs of tourists for dining, shopping, and entertainment [54,73].
	C9: Accommodations	Repair and transformation of residential buildings to create suitable experiential and residential spaces for tourists [74,75].

. Figure 1 shows the structure of a hierarchical evaluation system that facilitates systematic thinking for evaluation.

3. Research Objects and Methods

3.1. Study Area: Historic Sites in Huai’an

The Beijing–Hangzhou Grand Canal [76,77], built during the Spring and Autumn Periods, is the longest and largest ancient canal in the world. Huai’an is located in the Inner Canal section. It emerged during the Xia, Shang, and Zhou dynasties, then flourished in the Ming and Qing dynasties. As the center connecting the canals between the north and the south, it played an essential role in maintaining the economic lifeline of the feudal empire and witnessed the unique cultural tradition of canal transportation in ancient times. In 1986, Huai’an was listed as one of the Historical and Cultural Cities. It has more than 2200 years of history, which is rich in historical sites and cultural relics. It was once known as the “four metropolises” along the canal with Suzhou, Hangzhou, and Yangzhou. Figure 2 highlights the important position of Huai’an. The mansions of the Director-Generals of Grain Transport and the Grand Canal during the Ming and Qing dynasties were built here. The three historic sites of Fuma Lane, the Dutian Temple, and Hexia Ancient Town in Huai’an were selected as the research objects [78,79,80] because they are located beside the Grand Canal and have retained their tangible and intangible cultural heritage.

As shown in Figure 3a, Fuma Lane is located the northwest of Zhenhuai Building. It is about 300 m long. During the Ming Dynasty, Emperor Ming Hui built an ancestral hall for Captain Huang Chen in this lane, so it was called Fuma Lane. It still maintains the street pattern of the Ming and Qing dynasties. Figure 3b, the Dutian Temple is located in the Qingjiangpu District of Huai’an, covering an area of about 19.8 hectares with a construction area of 24.2 hectares. It was raised during the Qianlong period of the Qing Dynasty and contained 36 historical relics, such as the Dutian Temple, Wenhui Nunnery, and Bilu Nunnery. Figure 3c, Hexia Ancient Town, is located in Huai’an District, Huai’an. It was established at the end of the Spring and Autumn Period and had a history of about 2500 years. At present, Hexia Ancient Town maintains the architectural style, street layout, and stone roads of the Ming and Qing dynasties. The historical style is well preserved, and the representative streets and bridges within are Huzui Street, Estimated Clothes Street, Flower Lane, Tea Lane, and Luo Jia Bridge.

3.2. Multi-Criteria Decision-Making (MCDM)

Common in social and economic life, MCDM problems can be divided into three categories: selection, ranking, and classification. MCDM can help a decision maker rank a limited number of feasible solutions according to the merits of specific attributes to select an ideal solution that meets the decision makers’ needs [81,82]. This study used a combination of qualitative and quantitative research methods. The MCDM method can help decision makers, in different cases of historic lot preservation and renewal, to evaluate and select the solution that collected the urban planners’ ideal by ranking the advantages and disadvantages based on the characteristics of each solution’s respective attributes. Among the many multiple scenario evaluation, the commonly used analysis methods are Simple Additive Weighting (SAW) [83,84], Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) [85,86], Elimination et Choice Translating Reality (ELECTRE) [81,87], and AHP [88,89]. SAW is too simple, while TOPSIS needs to be simplified. Therefore, AHP applied in evaluating historical sites is beneficial for urban decision makers to make better decisions. The evaluation index system proposed in this paper for the preservation of historic sites can provide recommendations and references to administrative staff responsible for urban decision making. The thinking styles of such staff are usually not suited to excessively complex evaluation models. Hence, the analytic hierarchy process (AHP) was selected.

3.2.1. Concept and Application of Analytic Hierarchy Process

AHP was proposed by T.L. Saaty in the mid-1970s. It treats a multi-criteria decision-making problem as a complex system. In uncertain circumstances, the target is decomposed first into multiple aspects or criteria, then into several layers of multiple indexes, to determine the priority weight of each factor in each layer over a certain factor in the previous layer. Then, the final weights of various alternative solutions in the overall target are calculated and the solution with the largest final weight is identified as the optimal one [88]. Thus far, AHP has been applied to all kinds of decision-making and planning projects, such as large-scale system design, risk management, and historical architecture, in nearly 20 countries or regions [90]. Therefore, AHP is a key method for urban decision makers in urban planning studies.

3.2.2. Calculation Steps

The practical application of AHP [91] in problem solving can generally be divided into six steps: (1) identification of the problem; (2) formulating a hierarchical model; (3) construction of a judgment matrix; (4) single layer sorting; (5) overall hierarchical ranking; (6) consistency check. The last three steps must be performed layer by layer throughout the entire process and are described in detail below.

(1)

Construction of a judgment matrix

The factors of the same layer are subjected to pairwise comparison, thereby allowing judgment of the relative importance of the factors in each layer. Pairwise comparison is performed using a ratio of 1–9. For a group of n factors in the matrix, it is necessary to perform n(n − 1)/2 pairs of comparison. Then, the comparison results of these n factors are placed at the top of a pairwise comparison matrix A. Along the diagonal, there are n ratios used to compare the factors with each other, so they have a constant value of 1. The A value at the bottom of the matrix is the reciprocal of the value at the topmost diagonal position:

$$A=\left[a_{ij}\right]=\left[\begin{array}{cccc}1& a_{12}& \dots & a_{1n}\\ 1/a_{12}& 1& \dots & a_{2n}\\ \dots & \dots & \dots & \dots \\ 1/a_{1n}& 1/a_{2n}& \dots & 1\end{array}\right],$$

(1)

If the weight of a factor is given, it can also be expressed as:

$$A=\left[a_{ij}\right]=\left[\begin{array}{cccc}1& a_{12}& \dots & a_{1n}\\ 1/a_{12}& 1& \dots & a_{2n}\\ \dots & \dots & \dots & \dots \\ 1/a_{1n}& 1/a_{2n}& \dots & 1\end{array}\right]=\left[\begin{array}{cccc}{W}_1/W_1& W_1/W_2& \dots & W_1/W_n\\ W_2/W_1& W_2/W_2& \dots & W_2/W_n\\ \dots & \dots & \dots & \dots \\ W_n/W_1& W_n/W_2& \dots & W_n/W_n\end{array}\right]$$

(2)

where

$$a_{ij}=w_i/w_j,a_{ij}=1/a_{ji},W={[W_1,W_2,\dots ,W_n]}^T=\left[\begin{array}{c}{W}_1\\ W_2\\ \begin{array}{c}\dots \\ W_n\end{array}\end{array}\right]$$

(3)

where W_ij denotes the weight of factor i and a_ij denotes the ratio of relative importance between two factors (i = 1,2,…, n; j = 1,2,…, n).

(2)

Calculations of eigenvalues and eigenvectors

The eigenvalues and eigenvectors are used to solve the weights of the factors in each layer. An eigenvector is calculated by multiplying the factors in each column, taking the geometric mean of their products, and performing the following normalization:

$$W_i=\frac{{\left({\prod }_{j=1}^n{a}_{ij}\right)}^{\frac{1}{n}}}{{\sum }_{i=1}^n{\left({\prod }_{j=1}^n{a}_{ij}\right)}^{\frac{1}{n}}},i,j=1,2,\dots ,n$$

(4)

Pairwise comparison matrix A can be multiplied by solved eigenvector W_i to obtain a new eigenvector ${W_i}^{\prime }$, of which each vector value can be divided by the corresponding vector value of the original vector W_i, thereby obtaining the arithmetic mean (λ_max) of each value:

$$AW={\lambda }_{max}·W,$$

(5)

$$A=\left[\begin{array}{cccc}{W}_1/W_1& W_1/W_2& \dots & w_1/w_n\\ W_2/W_1& W_2/W_2& \dots & w_2/w_n\\ \dots & \dots & & \dots \\ W_n/W_1& W_n/W_2& \dots & w_n/w_n\end{array}\right]\left[\begin{array}{c}{W}_1\\ W_2\\ \dots \\ W_n\end{array}\right]=\left[\begin{array}{c}{W_1}^{\prime }\\ {W_2}^{\prime }\\ \dots \\ {W_n}^{\prime }\end{array}\right],$$

(6)

where

$${\lambda }_{max}=\frac{1}{n}(\frac{{W_1}^{\prime }}{W_1}+\frac{{W_2}^{\prime }}{W_2}+\dots +\frac{{W_n}^{\prime }}{W_n}).$$

(7)

(3)

Consistency check

The data placed into the pairwise comparison matrix are usually obtained from subjective expert judgments and influenced by many factors, so achieving consistency can be challenging. Therefore, it is necessary to conduct a consistency check and obtain the consistency index (C.I.):

$$C.I.=\frac{{\lambda }_{max}-n}{n-1}.$$

(8)

where ${\lambda }_{max}$ denotes the maximum eigenvalue of matrix A and n denotes the number of influencing factors. When C.I. is 0, these n factors are perfectly consistent in importance under a certain criterion. When C.I. is greater than 0, there are disagreements between the experts. Therefore, a smaller value of C.I. indicates higher consistency. Saaty suggested that C.I. be less than 0.1. In this paper, after repeated in-depth interviews with the selected experts, the opinions of all experts and scholars passed the consistency check.

4. Results and Discussion

4.1. Weight Analysis of Evaluation Indexes

As per T.L. Saaty on the suitable sample size of judges, the number of experts should be limited to seven or eight for the sake of consistency [92]. To take into account the characteristics of urban planning and decision making, as well as to improve the scientificity of the research and the accuracy of our conclusions, we selected experts and scholars according to the principle that factors such as specialty, region, and field of research can be compared transversely and longitudinally. A total of 11 experts in the fields of urban and rural planning (3), architecture (3), environmental ecology (2), and Huai’an Construction Industry Association (3) were interviewed. Each had an in-depth understanding of the historic sites in Huai’an and worked with preservation and restoration. First, they considered how to validate the effectiveness of the evaluation index system. Then, they performed pairwise comparisons on the above three evaluation facets and nine evaluation indexes. They also responded to questionnaires, of which 11 were validated by a consistency check (C.I. < 0.1).

Table 3. Weight statistics of various evaluation indexes for the preservation and restoration of historic sites.

Facet	Facet Weight	Evaluation Index	Index Weight	Comprehensive Weight	Ranking
D1 Statuses of historic relics	0.652	C1 Completeness of historic relics	0.548	0.357	1
		C2 Harmonization with surroundings	0.158	0.103	3
		C3 Innovation degrees of transformation and utilization	0.294	0.192	2
D2 Basic environmental conditions	0.179	C4 Convenience of transportation	0.236	0.042	7
		C5 Living conditions of inhabitants	0.203	0.036	8
		C6 Comfort degrees of public spaces	0.561	0.101	4
D3 Degree of tourism development	0.169	C7 Sightseeing and tourism	0.525	0.089	5
		C8 Dining and shopping	0.188	0.031	9
		C9 Accommodations	0.287	0.049	6

provides the weight statistics of various evaluation indexes for preserving and restoring historic sites.

In the facet layer, D₁ accounts for the largest weight (0.652), whereas D₃ has the smallest (0.169). Therefore, in the preservation and restoration of historic sites, primary consideration should be given to retaining the authenticity of historic relics. The top three indexes are C₁, C₃, and C₂, whereas the bottom two are C₅ and C₈, thus suggesting that emphasis should be placed not only on the protection of authentic historic relics but also on the preservation of the overall style, as well as the harmonization between the styles of the relics and their surroundings so that local historical styles could be continued. For the transformation and utilization of historic sites, gradual renovation should be adopted.

4.2. Empirical Study

The country with the most historical sites in the world is Italy, followed by China. Therefore, it is of great significance to choose Huai ‘an as the research study [93]. The data provided by the experts are subjected to a consistency check. After each evaluation index and its weights have been qualified, they can be used to determine the priority index (PI) of each solution proposed for the target layer. The value of PI can be acquired from the weight W_i solved as described in Equations (1)–(4) and the score X_ij of each index in each solution i can be acquired through simple weighting:

$${PI}_i={\sum }_{j=1}^n{W}_j\ast X_{ij}$$

(9)

where PI is used to judge the excellence of historic sites. Fuma Lane, Dutian Temple, and Hexia Ancient Town have similarities and differences between them.

Table 4. Descriptions of historic sites with evaluation indexes.

Index	Fuma Lane (O1)	Dutian Temple (O2)	Hexia Ancient Town (O3)
C1 Completeness of historic relics	Retained the historical styles and traditional street patterns of the Ming and Qing dynasties	About 200 years old	Retained architectural styles of the Ming and Qing dynasties
C2 Harmonization with surroundings	Disharmony between modern decorations and traditional street styles	Poor construction quality, diversified building forms, and disharmony with the style of the historic site	Loss of the authenticity of some historical buildings after repairs; harmonization and unification in style for most buildings
C3 Innovation degrees of transformation and utilization	Construction of new tourism distribution center and cultural exhibition center	Emergence of new tourist attractions based on the integration of Taoist culture and tourism	Repairing ancient buildings, demolishing old buildings, lacking features
C4 Convenience of transportation	Narrow streets, insufficient parking spaces, and inconvenient transportation	Narrow streets and uneven roads, impossible for motor vehicles to pass through	Retained traditional stone-paved roads, smooth traffic organization, and sufficient parking spaces
C5 Living conditions of inhabitants	Very old buildings, outdated infrastructure, and poor living conditions	Very old buildings, outdated infrastructure, and serious population aging	Inadequate preservation of dwellings
C6 Comfort degrees of public spaces	Insufficient public communication spaces, serious river pollution, disordered greening landscapes, and serious occupancy of public spaces	Lack of green landscapes and scattering of many low-efficiency, idle spaces	Clear rivers, beautiful green landscapes, and comfortable public spaces
C7 Sightseeing and tourism	Retained overall architectural styles of the Ming and Qing dynasties, which are characterized by blue bricks, black tiles, carved wooden windows, and ancient houses. Together with modern shops, the site offers rich experiences.	Presence of traditional architecture of the styles prevailing in the Ming and Qing dynasties, including religious architecture, former residences of celebrities, modern commercial relics, and numerous ancient dwellings	Profound cultural treasures, excellent tourism cultural resources, such as cultural customs, architectural arts, and folk customs
C8 Dining and shopping	Distributed with traditional gourmet food stores, coffee shops, and milk tea shops. Lack of diversity in types of businesses	Slow development of commerce and dining because only a small number of shops meet the daily living needs of residents	Distributed traditional gourmet food stores, photography shops, calligraphy and art shops, etc.; diversity in types of businesses
C9 Accommodations	Short tourist stays, lack of functions such as homestays	Mainly inhabited by locals; lacking functions such as homestays	Accommodations available around the scenic area

describes these three historic sites in terms of the above nine evaluation indexes.

Because of the complexity of determining the value of each evaluation index, pairwise comparisons are employed to obtain the score of each index in each solution. The three historic sites are subjected to pairwise comparisons with regard to each evaluation index. The calculation steps are the same as those of the above pairwise comparison matrix.

Table 5. Scoring of an expert for an example.

Evaluation Element	C1:C2	C1:C3	C2:C3
Degree of importance	3:1	5:1	3:1

shown the scoring of an expert for an example on the evaluation dimension “C₁”, “C₂” and “C₃”.

Therefore, the following pairwise comparison matrix A can be obtained:

$$A=\left[\begin{array}{ccc}1& 3& 5\\ \frac{1}{3}& 1& 3\\ \frac{1}{5}& \frac{1}{3}& 1\end{array}\right]$$

The sum of columns is calculated, and the results are shown in

Table 6. The sum of columns.

Evaluation Element	C1	C2	C3
C1	1	3	5
C2	1/3	1	3
C3	1/5	1/3	1
sum of columns	1.533	4.333	9

.

Each value in the matrix is standardized, and the calculation results are shown in

Table 7. Standardization.

Evaluation Element	C1	C2	C3
C1	0.653	0.692	0.556
C2	0.217	0.231	0.333
C3	0.130	0.077	0.111

.

The weight value of each factor can be obtained by calculating the average value of the row vector, and the results are shown in

Table 8. The value of weight.

Evaluation Element	Weight
C1	(0.653 + 0.692 + 0.556)∕3 = 0.634
C2	(0.217 + 0.231 + 0.333)∕3 = 0.260
C3	(0.130 + 0.077 + 0.111)∕3 = 0.106

.

According to Formula (7), the value of λ_max is 3.037. Then, according to Formula (8), the C.I. value is 0.019. According to T.L. Saaty, it is best when the C.I. is less than 0.1. Therefore, the expert’s assessment results are consistent with the identification of consistency. By analogy, the evaluation results of other experts are calculated, and the weight results of evaluation indicators for protection and renewal of historic lot are obtained. The evaluation results of the three historic sites are provided in

Table 9. Evaluation results of the three historic sites.

Facet	Evaluation Index	Comprehensive Weight	O1	O2	O3	PI (O1)	PI (O2)	PI (O3)
D1 Statuses of historic relics	C1 Completeness of historic relics	0.357	0.205	0.413	0.382	0.073	0.147	0.136
	C2 Harmonization with surroundings	0.103	0.237	0.302	0.461	0.024	0.031	0.047
	C3 Innovation degrees of transformation and utilization	0.192	0.406	0.334	0.260	0.078	0.064	0.050
D2 Basic environmental conditions	C4 Convenience of transportation	0.042	0.239	0.177	0.584	0.010	0.007	0.025
	C5 Living conditions of inhabitants	0.036	0.208	0.280	0.512	0.007	0.010	0.018
	C6 Comfort degrees of public spaces	0.101	0.262	0.141	0.597	0.026	0.014	0.060
D3 Degree of tourism development	C7 Sightseeing and tourism	0.089	0.337	0.213	0.450	0.030	0.019	0.040
	C8 Dining and shopping	0.031	0.280	0.132	0.588	0.009	0.004	0.018
	C9 Accommodations	0.049	0.160	0.223	0.616	0.008	0.011	0.030
Value of PI						0.266	0.308	0.426

.

They can be ranked as follows in descending order of the value of PI: Hexia Ancient Town, Dutian Temple (Qingjiangpu), and Fuma Lane. The results show that Hexia Ancient Town and Dutian Temple are the best preserved and restored, but Fuma Lane requires more resources. The degree of Convenience of transportation (C₄) and the Comfort degrees of public spaces (C₆) of Hexia ancient town scored high. Therefore, the value of PI is the highest. Hexia ancient town was listed as one of the critical historical locations for preservation in 2002. Since then, it has been protected and developed with a large investment. There are cities with more than 1000 years of history and complete historical locations in various regions of China, and these should be preserved and reused intact. From Table 5, city decision makers can judge, based on MCDM, the importance of each index, and thus, make systematic decisions.

4.3. Suggestion

In response to the demands for the preservation and renewal of historic sites in the new stage, an evaluation system that combines qualitative and quantitative as well as subjective and objective factors is established along three dimensions: historical culture, material space, and tourism development. By comprehensively evaluating the preservation statuses of the historic sites in Huai’an, optimization measures are put forward for their preservation and inheritance. First, the principle of integrity among the cultural values should be adopted to preserve the textures, styles, and patterns of historic sites while their historical and cultural elements should be integrated to provide systematic preservation and reflect the historical context. Authenticity should be emphasized in the preservation and repair, but the combination of appropriate innovations and support with modern life should be achieved. Second, supporting public service facilities and municipal infrastructure should be improved to raise the public’s quality of life and satisfaction. Public service facilities, community service centers, health service stations, fitness squares, and green squares should be renovated and augmented to meet the needs of daily public life. For municipal infrastructure, efforts should be made to improve the road networks and optimize the traffic environments without changes to the spatial scales or styles of streets with historic sites. Water supply drainage, power, telecommunications, health services, and other municipal infrastructure should be perfected. Finally, tourism should be developed in a reasonable manner with respect for the indigenous residents. The preservation and renewal of historic sites should give due consideration to the activation and utilization of historical architecture, appropriately highlight local traditional life and cultural customs, add commercial spaces that serve indigenous residents and tourists alike, and improve the service functions of historic sites to revitalize them.

5. Conclusions

Combining multi-criteria decision making with the analytic hierarchy process (AHP), we formulated a hierarchical evaluation index system for the factors influencing the preservation and restoration of historic sites. The system would help urban decision makers to effectively set the priorities of preservation and restoration efforts according to the opinions of professionals and experts, such as academic researchers, industry operators, and government policymakers. The effectiveness of this system was validated through a case study. The results indicate that AHP can be employed to effectively construct an evaluation index system of influencing factors for the preservation and restoration of historic sites. Moreover, this system is scientific and easy to operate.

The advantages of the evaluation index system are as follows. (1) This system effectively combines targets with data, concretizes the evaluation targets, and decomposes them into multiple indexes that are easier to calculate by layer-by-layer decomposition and simplification. (2) The system draws upon the experiences and suggestions of the experts, who provide references for determining the weights of the indexes. (3) This system guarantees the scientificity of the weights. In the calculation of index weights, this system provides a validity and consistency check on expert evaluation to ensure the reasonableness and scientificity of subjective judgments, thereby achieving a perfect combination of qualitative judgments and quantitative research. Therefore, AHP has many advantages, such as the combinations of qualitative with quantitative analyses, subjective with objective analyses, and analyses with concrete practice.

According to the evaluation of the factors influencing the preservation and restoration of historic sites, the statuses of historic relics account for the largest weight, thus occupying an important position in preservation and restoration. For the key historic sites of an old urban area where historic buildings have suffered severe damage but the urban texture remains, it is feasible to restore the historical style of the entire area through moderate reconstruction. However, it is necessary to carefully explore restoration techniques to ensure “restoring the old as the old”. The structures being restored should be integrated into the historical environment of the area to the maximum extent possible in order to maintain the continuity and integrity of the historical environment, as well as achieve harmonization with the overall style of the area.

The factors influencing the preservation and restoration of historic sites were analyzed by AHP. The findings in this paper can provide practical guidance for such efforts. The statuses of historic relics are the most important influencing factor. Further in-depth research should be conducted to clarify and formulate the modes and mechanisms of preservation and restoration in accordance with the goals of sustainable development. The study area and samples of this study require expansion. Differences in histories, cultures, and customs mean that the characteristics of historic sites would vary across different countries and regions. Therefore, the selection of only three historic sites in Huai’an, China, for investigation and empirical research has certain limitations, which would require the study area to be expanded to other regions or countries.