Value-Based Decision to Redevelop Transportation Facilities: A Case Study of an Abandoned Airport

: Value-based decision making is the consideration of function and cost in the decision to select the highest possible option. Reviews to previous studies showed that there is a lack of consideration of the criteria of value in the decision-making process. Hence, this research aims to identify the criteria for redeveloping transportation facilities based on function and cost. The ultimate goal of this research is to select the best value alternative for project redevelopment. An abandoned airport was chosen as the case study to evaluate the decision made by the government to invest in the project of transforming the abandoned airport into a hospital that aims to cater to the increasing demand for healthcare. A quantitative and qualitative approach was applied through literature review, survey, and interview to experts in the area of transportation facilities development. Statistical descriptive analysis was used to analyse the ﬁrst survey, which was to investigate the critical factors under the category of function. The second survey was conducted to select the most valuable alternative for the redevelopment by utilising the Analytical Hierarchy Process (AHP), and it was found that the transportation hub is the most valuable alternative for redeveloping the abandoned airport. The result was then validated by an expert from the industry, and it can be concluded that the value-based decision-making model can be used in enhancing the decision of the redevelopment of transportation facilities by considering both function and cost.


Introduction
Redevelopment is a process of land use development to revitalise the urban space through physical, economic, and social indicators [1,2]. It is necessary for redeveloping urban areas since the global population continues to grow larger with the ageing infrastructure and abandoning of urban manufacturing sites [3]. Lots of consideration need to be taken into account during the decision-making process for the redevelopment. Thus, it is essential to consider multiple criteria that affect redevelopment such as technological, economic and environmental [4]. Changes in lifestyle, policies, and environmental condition are some criteria that may change the productivity of a facility in improving the land value, which may lead to the closure of the facility and its abandonment.
Transportation facilities are one of the most important infrastructures in a country. They serve as a hub that connects different locations and allow travelling between different locations to be done effectively and efficiently. Moreover, they can help to connect the cities in a country and allow development to progress at a higher rate. It is necessary to understand how transportation facilities will affect the development of a country. Therefore, it is important to determine transportation facilities' efficiency and relate their performance to a country's development in all categories [5]. Furthermore, for a transportation facility, it It can be concluded that this paper is needed to enhance the decision for redeveloping the transportation facility. The evaluation process should not be based on criteria of function only, but it needs to include the criteria of cost since the lack of considerations for the "value" of investment for redeveloping property has become the obstacle for sustainable development [18]. Hence, because of the necessity of decision making for redeveloping the valuable transportation facilities, the cost of each alternative needs to be taken into consideration too.

Literature Review
A value-based decision is a unique approach in selecting the best alternative that considers the criteria of both function and cost. Reviews to previous studies related to the implementation of value-based decision as well as project redevelopment have been conducted to build the conceptual model. Reviews on both criteria of function and cost also being further explored to strengthen the conceptual model of this research.

Value-Based Decision Making for Redevelopment
A value-based decision is a structural and analytical process which aims to select an alternative with the lowest cost while having all the required function at the same time maintain its quality and performance [9]. In value-based decision making, desirable benefit and considerable cost are taken into consideration to evaluate the value of the alternatives [18]. According to Pica [20], the value of an investment is defined as the ideal combination of life cycle cost and the function of the goods or services to meet the user's requirements. A value of an alternative can be obtained by comparing function and cost [21]. An alternative can be determined as a valuable alternative if the function is equal with cost, meaning the value of the alternative is one. A high-value alternative will have It can be concluded that this paper is needed to enhance the decision for redeveloping the transportation facility. The evaluation process should not be based on criteria of function only, but it needs to include the criteria of cost since the lack of considerations for the "value" of investment for redeveloping property has become the obstacle for sustainable development [18]. Hence, because of the necessity of decision making for redeveloping the valuable transportation facilities, the cost of each alternative needs to be taken into consideration too.

Literature Review
A value-based decision is a unique approach in selecting the best alternative that considers the criteria of both function and cost. Reviews to previous studies related to the implementation of value-based decision as well as project redevelopment have been conducted to build the conceptual model. Reviews on both criteria of function and cost also being further explored to strengthen the conceptual model of this research.

Value-Based Decision Making for Redevelopment
A value-based decision is a structural and analytical process which aims to select an alternative with the lowest cost while having all the required function at the same time maintain its quality and performance [9]. In value-based decision making, desirable benefit and considerable cost are taken into consideration to evaluate the value of the alternatives [18]. According to Pica [20], the value of an investment is defined as the ideal combination of life cycle cost and the function of the goods or services to meet the user's requirements. A value of an alternative can be obtained by comparing function and cost [21]. An alternative can be determined as a valuable alternative if the function is equal with cost, meaning the value of the alternative is one. A high-value alternative will have value more than once, which means that it gives more functions/benefits than the cost. In contrast, a low-value alternative has a value of less than one, which means that the functions/benefits received are deficient compared to the expenses. To evaluate the alternatives of the redevelopment, numerical data on both function and cost are necessary. AHP is a suitable approach to select the best alternatives for development by considering the criteria of function and cost [18]. Life cycle cost (LCC) is used as the approach for getting the weight on the cost of each alternative. LCC is the useful economics construct that underlies the entire lifespan of the asset from conception to demolition which includes construction, maintenance, operation, occupation, and end-of-life cost [20,22,23]. The formula for calculating LCC is as follows: where: C ic -Initial cost C inst -Delivery and installation cost C e -Energy cost C o -Operational cost C m -Maintenance cost C s -Downtime cost C d -Decommissioning cost

Reviews to Previous Case Studies of Decision Making in the Redevelopment Project
In this era of urbanisation, redevelopment is vital as the decrease in available space to accommodate the urban sprawl and new construction. Urban redevelopment is a process of revitalising an existing developed area [16]. Moreover, redevelopment aids in optimising urban land use [24]. It is necessary to evaluate and identify the impacts of redevelopment based on multiple criteria such as technical, economic, social, and environmental indicators [3,4,[25][26][27]. However, effective decision support is required to minimise the uncertainties and risks when solving the challenges in construction project information flows [4]. In addition to this, there is a lack of focus on technical and design aspects, as well as the effects brought about by redevelopment towards cultural, social, economic, and environmental sustainability during the redevelopment process [27]. Therefore, several recent studies [3,4,15,16,25,28,29] have recommended that a new model shall be developed or revise the existing techniques to make a more reliable decision for redevelopment. It has been found that several case studies are being conducted by researchers around the globe. Each of the case studies is discussed in the following subsections. The case studies were also reviewed to investigate the suitable and potential criteria for developing the conceptual model of this research. The criteria are further discussed in Section 2.3.

Old Equipment Repair Factory in Vilnius
The redevelopment of an old equipment repair factory in Vilnius was evaluated based on three alternatives which were the renovation of the existing building to adapt to current needs while maintaining or slightly altering the original object and its previous defined function (a 1 ), renovating the building into loft-type housing while maintaining its architectural-urban expression (a 2 ), and demolition of the current building and implementing a new construction project (a 3 ) [4]. The selection of the alternatives was based on a list of parameters that can be grouped under economic, environmental, and technological aspects. The criteria were analysed by using the initial decision-making matrix while the Weighted Aggregated Sum Product Assessment method with grey numbers (WASPAS-G) was applied to prioritise the results. To reach a reliable decision, the redevelopment project was then validated by using Multiple Criteria Decision Making (MCDM) and Building Information Modelling (BIM) techniques. The results showed that a 2 is the best alternative, followed by a 3 and a 1 . Pier Arts Centre (PAC) was being assessed after its renovation based on technical, social, and economic sustainability pillars [27]. Social and economic impacts of PAC were assessed through statistical analysis as well as a quantitative and qualitative method based on a list of indicators whereas the environmental impacts were evaluated using energy benchmarking and modelling. The renovation of PAC had indicated that redevelopment brings positive impacts to local social, cultural, and economic development [27].

Villages in the City (ViCs) in Shen Zhen
China underwent rapid urbanisation due to its massive economic reformation which led to the need for urban land redevelopment in the so-called "villages in the city" (ViCs) [15]. The poor infrastructure and disorganized built environment of ViCs affected sustainable development. Residents of ViCs near the redevelopment projects were interviewed to evaluate the effect of indirect displacement related to the rising housing prices and rents after redevelopment [29]. It was found that the location of the land and its existing rent were the main influencers for redeveloping industrial sites [15].

Abandoned Railway Lines in Italy
There are more than 7500 km of disused railways in Italy and the railway line which is about 16.5 km between the city of Pinerolo and the Pellice Valley was selected for redevelopment purposes [30]. The best alternatives for the revitalisation of the abandoned railways based on the environmental and socio-economic impacts and the performances of each alternative were evaluated by using a value tree. The listed alternatives were greenway, rail-banking, an extension of the urban railway service, old station recovery, and no action [30]. The results showed that the best solution was to requalify the disused railways as a greenway which converts the abandoned railways into a green corridor [30].

Criteria for Redevelopment Decision Making
Based on the previous studies, there are four main criteria with a list of sub-criteria. The impacts of redevelopment and the factors affecting redevelopment are evaluated based on these criteria. Therefore, they can be used as a reference in this study in developing the value-based decision-making model, as summarised in Table 1.

Methodology
The research flow is shown in Figure 2. This research starts with identifying and analysing the criteria for the redevelopment of transportation facilities. Reviews of previous studies have been conducted to identify the possible criteria for the redevelopment. A pilot study through an interview with experts was also conducted in the preliminary stage to evaluate the feasibility of research and the criteria for the redevelopment. Then, a questionnaire was prepared based on the identified criteria from the grounded theory. The first survey aims to identify and prioritise the most important and relevant criteria of function for the redevelopment of transportation facilities. A primary survey was administered to the stakeholders of transportation facilities in Malaysia. The data collected were analysed through a scatter plot analysis of mean and standard deviation to prioritise and select criteria for redeveloping the abandoned airport. In addition to this, potential decision-makers for the second survey were also identified from this primary survey. From this first survey, the top 5 criteria of function were selected to be the main criteria in the decision-making model which are further proceeded with AHP in the second survey.  [15,29] Social During the literature review, it was also found that social factors are necessary, whereby some of the criteria support the improvement of economic development.
Households in poverty [28] Population in zero car households [28] Tourism rate [30] Physical activity [25] In the second step, a qualitative approach was adopted. A pairwise comparison between each criterion and alternatives was conducted through the second survey. Five potential decision-makers with the background of developer, contractor, and politician have been selected to answer the questionnaires. On the other hand, the initial cost as well as operational and maintenance cost for each of the alternatives were obtained through online resources and validated by the expert. The local priorities for the alternatives based on function and cost were derived from the data collected through the Analytical Hierarchy Process (AHP). AHP was chosen as the method in selecting the best alternative for the redevelopment since there are multiple decision criteria considered in the selection. This method is applicable for a single decision-maker, however, this study involved 5 respondents as decision-makers, and the result from each decision-maker is compared for further analysis. The best valuable alternative for redeveloping the abandoned airport was synthesised through the AHP model and finally validated by an expert. The AHP method is considered a systematic method that presents several issues in the form of a hierarchy [36]. The AHP method has been used in this research due to the need to involve experts in the investigated issue, and not only basing outcomes on specific research data and analysis [37].

Pilot Study
A pilot study was conducted with two experts who specialised in project development and transportation engineering. Both experts hold around 20 years of experience. The main purpose of conducting the pilot study is to evaluate the feasibility of the research also to verify the identified criteria from previous studies. Based on the pilot study, 9 criteria were nominated as the function for redeveloping the abandoned airport. The criteria were selected based on the agreement from both candidates whereas if there is any disagreement from any side, the criteria will not be considered. Therefore, only green development, building safety, comfortability, building age, type of land use, accessibility to public transport, building materials, the economic condition of local communities, and the capability to attract tourists were selected as the criteria for redeveloping the abandoned airport in the primary survey. Besides that, both experts have suggested a transportation hub as the alternative for redeveloping the abandoned airport. In addition to this, the experts also proposed to rebuild the airport, shopping mall, hotel, or food court. The results from the pilot study are summarised in Table 2.

Pilot Study
A pilot study was conducted with two experts who specialised in project development and transportation engineering. Both experts hold around 20 years of experience. The main purpose of conducting the pilot study is to evaluate the feasibility of the research also to verify the identified criteria from previous studies. Based on the pilot study, 9 criteria were nominated as the function for redeveloping the abandoned airport. The criteria were selected based on the agreement from both candidates whereas if there is any disagreement from any side, the criteria will not be considered. Therefore, only green development, building safety, comfortability, building age, type of land use, accessibility to public transport, building materials, the economic condition of local communities, and the capability to attract tourists were selected as the criteria for redeveloping the abandoned airport in the primary survey. Besides that, both experts have suggested a transportation hub as the alternative for redeveloping the abandoned airport. In addition to this, the experts also proposed to rebuild the airport, shopping mall, hotel, or food court. The results from the pilot study are summarised in Table 2. Table 2. Results from the pilot study.

No. Criteria Required for Redeveloping The Abandoned Airport Expert (A) Expert (B)
1.
Green development Strongly agree Agree 2.
Design complexities Disagree Agree 3.
The time required for the construction work Neutral Neutral 4.
Building safety Agree Neutral 5.
Building age Agree Agree 7.
Floor-to-area ratio and floor level Disagree Disagree 9.
Type of land use Strongly agree Strongly agree 10.
Accessibility to public transport Agree Agree 11.
Building materials Neutral Strongly agree 12.
The economic condition of the local communities Agree Agree 13.
The capability of the property to attract tourists Neutral Agree 14.
Ability to facilitate outdoor activities by the local communities Disagree Agree The suggestion of alternatives for redeveloping the abandoned airport.
• Hotel • Rebuild the airport

Survey 1: Prioritising the Decision Criteria
Survey 1 aims to collect data from the stakeholders and potential users to prioritise the criteria and potential alternatives for redeveloping the abandoned airport. A Likert scale was used to capture the perspective of respondents on their agreement to the criteria of function to be considered in redeveloping the abandoned airport. This is necessary for achieving research objectives. A total of 86 responses were obtained from the primary survey. Referring to Figure 3a, 73% of the respondents have an educational level of bachelor's degree and 12% of the respondents are at SPM level. Besides that, the percentage of the respondents having a master's degree and diploma are equal at 5%. Only 2% of the respondents completed their studies up to doctorate level, whereas 3% of the respondents selected others. Additionally, in Figure 3b, 36% of the respondents have a background of studies in education followed by 22% with a background in engineering studies. Next were the fields of study of business and finance, accounting, and quantity surveying at 7%, 6%, and 3% respectively. Twenty-six percent of the respondents have academic qualifications in other fields such as construction and property management, operation management, economics, and medicine. selected others. Additionally, in Figure 3b, 36% of the respondents have a background of studies in education followed by 22% with a background in engineering studies. Next were the fields of study of business and finance, accounting, and quantity surveying at 7%, 6%, and 3% respectively. Twenty-six percent of the respondents have academic qualifications in other fields such as construction and property management, operation management, economics, and medicine. From the survey, the mean and standard deviation of each criterion are calculated; afterwards, they are plotted in the scatter plot of mean and standard deviation. The scatter plot of mean and standard deviation analysis was used to rank the criteria of function. The scatter plot analysis is presented in Figure 3, the axis (x) is the mean value, and the ordinate (y) is the standard deviation value. The top five rankings of the criteria were chosen as the main criteria of function for redeveloping the abandoned airport. Referring  From the survey, the mean and standard deviation of each criterion are calculated; afterwards, they are plotted in the scatter plot of mean and standard deviation. The scatter plot of mean and standard deviation analysis was used to rank the criteria of function. The scatter plot analysis is presented in Figure 3, the axis (x) is the mean value, and the ordinate (y) is the standard deviation value. The top five rankings of the criteria were chosen as the main criteria of function for redeveloping the abandoned airport. Referring to Figure 4, the analysis showed that all criteria fall under Region 3 which indicates that all criteria have a high mean and high standard deviation. Therefore, the criteria in this region with lower standard deviation were prioritised first. Based on Table 3, building materials have the highest mean of 4.3953 and the lowest standard deviation of 0.8849, hence, it is the most important criteria for project redevelopment decision making. Besides, accessibility to public transport is ranked after building materials with a mean of 4.3837 and a standard deviation of 0.8966. Building safety and economic condition of local communities share the same mean of 4.2907. However, the standard deviation of economic condition of local communities is lower than the building's safety, as illustrated in Figure 4. This indicates that the economic condition of local communities is more important than the building's safety for project redevelopment decision making. Hence, the economic condition of local communities is selected as the third main criterion for redeveloping the abandoned airport. In addition to this, comfortability is chosen as the fourth main criterion because of its lower standard deviation as compared to other criteria. Lastly, the type of land use is selected as one of the main criteria with a mean of 4.1395 and a standard deviation of 0.9476 which is slightly higher than the standard deviation of comfortability of 0.9258. Based on the result, the five criteria of function that are included in the AHP decision-making model are building materials, the economic condition of local communities, accessibility to public transport, type of land use, and comfortability.  Five potential alternatives which are to rebuild the airport, transportation hub, food court, shopping mall, and hotel were listed in the survey form. The respondents were  Five potential alternatives which are to rebuild the airport, transportation hub, food court, shopping mall, and hotel were listed in the survey form. The respondents were asked to arrange the listed alternatives from the most to the least suitable potential alternatives. They were also allowed to suggest potential alternatives for redeveloping the abandoned airport. Figure 5 shows the ranking of potential alternatives from the stakeholders. It shows that 49.4% of the respondents have chosen to rebuild the airport as their first choice followed by turning it into a transportation hub at 27.7%. On the other hand, none of the respondent selected a hotel as their first choice of alternative. In short, the most potential alternative can be arranged in the order to rebuild the airport followed by a transportation hub, food court, shopping mall and hotel. Respondents also suggested redeveloping the abandoned airport into mixed development which consists of residential and commercial components, car parts, eco-friendly park, entertainment hub and theme park. However, the alternative of rebuilding the airport was rejected because the government has decided to build a new airport in another part of Kapit-Tunoh. In addition to this, on 4 July 2020, Deputy Health Minister Datuk Aaron Ago Dagang suggested building a new hospital in Kapit [14]. According to Borneo Post [14], the new hospital was proposed to be constructed at the abandoned airport site for a long-term plan to cater to the increasing demand for healthcare by the local communities. Therefore, the alternative of rebuilding the abandoned airport was replaced with plans for a hospital. Moreover, the food court can be classified under both transportation hub and shopping mall, too. Based on the majority rating preference of the stakeholders and decision from the government, three potential alternatives for redeveloping the abandoned airport are a hospital, transportation hub, and shopping mall. increasing demand for healthcare by the local communities. Therefore, the alternative of rebuilding the abandoned airport was replaced with plans for a hospital. Moreover, the food court can be classified under both transportation hub and shopping mall, too. Based on the majority rating preference of the stakeholders and decision from the government, three potential alternatives for redeveloping the abandoned airport are a hospital, transportation hub, and shopping mall.

Evaluation of Best Alternative Using AHP
The second survey was conducted to collect data from five decision-makers. It aims to prioritise and select the best value alternative for redeveloping the abandoned airport. Five main criteria of function and three potential alternatives were selected from a primary survey for pairwise comparison through a questionnaire. In the first section of the second survey form, the criteria of function were compared to each other with a scale of 1-9. In the second section, each alternative was compared to each other based on the five different main criteria. The five main criteria are building materials (f1), the economic condition of local communities (f2), accessibility to public transport (f3), types of land use (f4), and comfortability (f5). Besides that, the initial cost (c1) and operational and maintenance cost (c2) for each alternative were identified as the criteria of cost. Three alternatives were proposed which are transportation hub (a1), shopping mall (a2), and hospital (a3). The decision hierarchy model is presented in Figure 6.
A value-based decision is a decision-making process that considers the criteria of both function and cost. In the AHP model, the weight of each criterion of function was calculated from the responses given by respondents as mentioned above. For getting the weight of the criteria of cost, the authors used LCC to calculate the cost as data for com-

Evaluation of Best Alternative Using AHP
The second survey was conducted to collect data from five decision-makers. It aims to prioritise and select the best value alternative for redeveloping the abandoned airport. Five main criteria of function and three potential alternatives were selected from a primary survey for pairwise comparison through a questionnaire. In the first section of the second survey form, the criteria of function were compared to each other with a scale of 1-9. In the second section, each alternative was compared to each other based on the five different main criteria. The five main criteria are building materials (f 1 ), the economic condition of local communities (f 2 ), accessibility to public transport (f 3 ), types of land use (f 4 ), and comfortability (f 5 ). Besides that, the initial cost (c 1 ) and operational and maintenance cost (c 2 ) for each alternative were identified as the criteria of cost. Three alternatives were proposed which are transportation hub (a 1 ), shopping mall (a 2 ), and hospital (a 3 ). The decision hierarchy model is presented in Figure 6.
A value-based decision is a decision-making process that considers the criteria of both function and cost. In the AHP model, the weight of each criterion of function was calculated from the responses given by respondents as mentioned above. For getting the weight of the criteria of cost, the authors used LCC to calculate the cost as data for comparison and calculating the weight. Finally, it was used to evaluate the value of each alternative as further discussed in Section 4.3.8. Data for cost were obtained from [14,38]. In addition to this, the demographic profiles of five potential decision-makers are discussed and demonstrated in Table 4. The responses of each decision-maker are discussed in More than 20 years Contractor Director 5 More than 20 years Developer Director All the respondents had been to Kapit and were familiar with the demographic of Kapit and its development. Four out of five respondents had work experience of more than 15 years. The occupations of the respondents include developer, contractor, and politician. In addition to this, three of the respondents are directors of organizations while the other two respondents are a member of parliament and a project coordinator. They were chosen as potential decision-makers as they are highly experienced in property development and construction. The backgrounds of each decision-maker are presented in  All the respondents had been to Kapit and were familiar with the demographic of Kapit and its development. Four out of five respondents had work experience of more than 15 years. The occupations of the respondents include developer, contractor, and politician. In addition to this, three of the respondents are directors of organizations while the other two respondents are a member of parliament and a project coordinator. They were chosen as potential decision-makers as they are highly experienced in property development and construction. The backgrounds of each decision-maker are presented in Table 4. The details of calculation and analysis on the AHP decision making for each respondent are presented in Appendix A.

Best Alternative Selected by Respondent 1
Based on the opinion of respondent 1, type of land use (f 4 ) is the most important criterion for redeveloping the abandoned airport with a weightage of 0.51713 followed by the economic condition of local communities (f 2 ), with a weightage of 0.24571, as shown in Table 5. The third most important criterion is accessibility to public transport (f 3 ), followed by building materials (f 1 ) and comfortability (f 5 ). In addition, the alternatives were compared with each other based on different main criteria. The summary of the data from respondent 1 is shown in Table 5. From the results, respondent 1 feels that a shopping mall (a 2 ) is the potential alternative for redeveloping the abandoned airport by considering the criteria of function only with a total weightage of 0.60717. The choices are then followed by transportation hub (a1) and hospital (a 3 ) with a weightage of 0.26628 and 0.12655, respectively. Ability to improve the land value is becoming important in redeveloping buildings [39]. Looking at the location of the abandoned airport, which is surrounded by residential buildings, the selected alternative becomes possible since there will be demand for it. The alternative suits the criteria for improving the land value. Referring to Table 6, respondent 2 thinks that the economic condition of local communities (f 2 ) is the most important criterion for redeveloping the abandoned airport with a weightage of 0.59137. The second most important criterion is type of land use (f 4 ), followed by accessibility to public transport (f 3 ), building materials (f 1 ), and comfortability (f 5 ). The weights for the criteria are 0.15247, 0.12761, 0.08821, and 0.04035, respectively. Additionally, the alternatives were compared with each other based on different main criteria. Table 6 shows the synthesis of the data from respondent 2. From the synthesized results, transportation hub (a 1 ) is the most potent alternative as chosen by respondent 2, followed by shopping mall (a 2 ) and hospital (a 3 ) with a weightage of 0.70565, 0.22076, and 0.07359 accordingly. The respondent agrees with keeping the building use as a transportation facility, but changes its function into a transportation hub; this is because the respondent is greatly concerned about the economic condition of the local communities. Participation of the local communities becomes crucial in keeping the sustainability of the building, particularly in economic and social aspects. This finding relates to the results found by Chang and Kuo [40], Yeh et al. [41], and Khalil et al. [42]. Referring to Table 7, the economic condition of local communities (f 2 ) has the highest weightage of 0.56517. Hence, respondent 3 has rated it as the most important criterion for redeveloping the abandoned airport. Besides that, accessibility to public transport (f 3 ) is the second most important criterion with a weightage of 0.20462, followed by building materials (f 1 ), with a weightage of 0.12476. According to respondent 3, type of land use (f 4 ) is the fourth most important criteria for project redevelopment. However, he had the same opinion as other respondents, whereby comfortability (f 5 ) is the least important criteria in decision making for the abandoned airport. The results from respondent 3 are synthesised in Table 7. Based on the results, respondent 3 thinks that transportation hub (a 1 ) is the most probable alternative with a weightage of 0.69818. On the other hand, the second potential alternative is a hospital (a 3 ) and the third potential alternative is a shopping mall (a 2 ). This preference of respondent 3 is similar to that of respondent 2, whereby both have a similar perspective in placing the economic condition of local communities as the most important criterion in keeping the sustainability of both economic and social aspects [40][41][42], thus the selected alternative is a transportation hub. Respondent 4 thinks that access to public transport (f 3 ) is the most important criterion when deciding on the redevelopment of the abandoned airport. According to Table 8, the weightage of accessibility to public transport (f 3 ) is 0.50294, as rated by respondent 4. The economic condition of local communities (f 2 ) has the second-highest weightage of 0.24601, followed by building materials (f 1 ), with a weightage of 0.14295. These criteria are followed by the weights of type of land use (f 4 ) and comfortability (f 5 ), 0.07990 and 0.02820, respectively, which are ranked at number 4 and 5. Based on Table 8, hospital (a 3 ) is the most probable alternative as decided by respondent 4 with a weightage of 0.72867. The alternatives are then arranged in the order of transportation hub (a 1 ), with a weightage of 0.21875 and shopping mall (a 2 ), with a weightage of 0.05259. Although respondent 4 expressed concern about accessibility to public transport, the best alternative for the redevelopment according to them is the hospital. The result appears to be based on the accumulative analysis of the other criteria. The hospital can enhance the land value of the building by looking at the provided demand. It was found that communities contribute to the sustainability of the hospital [43]. Based on Table 9, building materials (f 1 ) with a weightage of 0.50710 is the most important criterion for redeveloping an abandoned airport, as rated by respondent 5. Type of land use (f 4 ) has a weightage of 0.25111, ranked at number 2, followed by the economic condition of local communities (f 2 ), with a weightage of 0.13636. In addition to this, the weightage of accessibility to public transport (f 3 ) is 0.07695, whereas that of comfortability Sustainability 2021, 13, 4959 15 of 24 (f 5 ) is 0.02848. According to respondent 5, transportation hub (a 1 ) has the highest weightage from the synthesised results, as tabulated in Table 9. It is the most probable alternative for project redevelopment with a weightage of 0.64441. Apart from that, the weightage of the hospital (a 3 ) is 0.29760 with a ranking of 2. Lastly, shopping mall (a 2 ) is the least suitable potential alternative from the view of respondent 5. 4.3.6. Best Alternative Selected by All Respondents Table 10 shows the synthesised result of AHP on the alternatives when considering the five criteria of function for redeveloping the abandoned airport. The ranking of the alternatives is concluded by considering the opinions of the five potential decisionmakers. The results show that the ranking order of the alternatives from the ones with the most potential to those with the least is the transportation hub (a 1 ), hospital (a 3 ), and shopping mall (a 2 ). The result presented in Table 10 is the rank of alternative without considering cost, i.e., a decision based on function only. The result of the value-based decision, which considers both function and cost, is presented in Table 11 and further explained in Section 4.3.7. Initial cost (c 1 ) and operational and maintenance cost (c 2 ) have been identified and considered in value-based decision making for the redevelopment of an abandoned airport. In this research, the transportation hub was assumed to be similar to the shopping mall structural design and have similar operational and maintenance cost. Hence, the initial costs of a transportation hub and shopping mall range from USD542.42 to USD723.22 per m 2 , whereas the hospital involves costs of USD843.76 to USD1165.19 per m 2 [44]. Additionally, according to Lin [2], the monthly operational and maintenance cost for the transportation hub and shopping mall is USD8.288 per m 2 . On the other hand, the total expenditure on public hospitals in Malaysia in 2017 was USD3,830,812,978.30 [38,45,46]. According to the Ministry of Health of Malaysia [47], the total number of official beds in Malaysia was 42,302, with an average size of 204 m 2 per bed. Hence, the operational and maintenance cost of a hospital is estimated at USD32.615 per m 2 per month. For the AHP matrix and weightage calculations, the alternative with the lower cost was preferred. Based on Table 11, hospital (a 3 ) has the greatest loss of 0.873016. Hence, transportation hub (a 1 ) and shopping mall (a 2 ) will be of greater potential by considering the criteria of cost only.

Integrated Perspective on AHP Model
The most valuable alternative for redeveloping the abandoned airport is selected by considering the criteria of function and cost. Besides that, value is defined as the function of the building over its life cycle cost [8]. The alternative will only be accepted when the value is more than 1 while the alternative with a value of less than 1 will be rejected. Referring to Table 12, the transportation hub (a 1 ) is selected as the most valuable alternative with the highest value of 2.754932 as compared to others. On the other hand, based on the result shown in Table 10, the hospital (a 3 ) is ranked above the shopping mall (a 2 ) when considering the criteria of function only. However, when the cost is taken into consideration, a shopping mall (a 2 ) will be more valuable than a hospital (a 3 ) as the alternative for redeveloping the abandoned airport. Table 12 shows that the value of the hospital (a 3 ) is 0.456892 while the value of the shopping mall is 1.112002, which is more than 2 times higher than that of the hospital. This is because the cost of owning a hospital is extremely high compared to that of a shopping mall. Hence, the proposal of the government to build the hospital on the abandoned site is rejected as the value of the hospital is lower than 1. Figure 7 illustrates the value of the alternatives based on the scatter plot. It shows that the alternatives located above the baseline are valuable for project redevelopment. Keeping the sustainability of a building is a challenge, and it needs the support of its surroundings, particularly the local communities as the users of the building [40][41][42]. Thus, it is necessary to investigate the demand on the building use to be able to predict the revenue or benefits that can be obtained to be able to develop a valuable building. With this finding, it can be concluded that value-based decision making becomes necessary to apply in selecting the most suitable alternative, particularly in the development of a project [18,48].

Validation of Criteria through Previous Studies
Building materials (f 1 ), the economic condition of local communities (f 2 ), accessibility to public transport (f 3 ), type of land use (f 4 ), and comfortability (f 5 ) were chosen as the criteria for redeveloping the abandoned airport and validated through previous studies, as shown in Table 13. The importance of the criteria of function was arranged in the order of f 2 > f 4 > f 3 > f 1 >f 5. The ranking of function criteria, based on average weightage calculated from the weightage in Tables 5-9 for each respondent, is presented in Table 13. Furthermore, the cost of the facilities must be considered in the preliminary stage as the redevelopment of a project is highly influenced by the cost of the facilities [24,30].

Validation of Criteria through Previous Studies
Building materials (f1), the economic condition of local communities (f2), accessibility to public transport (f3), type of land use (f4), and comfortability (f5) were chosen as the criteria for redeveloping the abandoned airport and validated through previous studies, as shown in Table 13. The importance of the criteria of function was arranged in the order of f2 > f4 > f3 > f1 >f5. The ranking of function criteria, based on average weightage calculated from the weightage in Tables 5-9 for each respondent, is presented in Table 13. Furthermore, the cost of the facilities must be considered in the preliminary stage as the redevelopment of a project is highly influenced by the cost of the facilities [24,30]. Table 13. Validation of criteria through previous studies.

Function
Average Weightage Ranking Sources Building materials (f1) 0.18485 4th Building materials are important in deciding alternatives for project redevelopment to ensure green development [15].
The economic condition of local communities (f2) 0.35692 1st The socio-economic factor is significantly correlated with project redevelopment as the economic condition can increase redevelopment brings [25,28]. Accessibility to public transport (f3) 0.21092 3rd Accessibility of the project site is the key determinant for project redevelopment [15].
Type of land use (f4) 0.21555 2nd Type of land use is one of the most important factors affecting project redevelopment as it can affect property values [15,28].
Comfortability of the building such as control and indoor quality is important for sustainable project redevelopment [27,32].

Function Average Weightage Ranking Sources
Building materials (f 1 ) 0.18485 4th Building materials are important in deciding alternatives for project redevelopment to ensure green development [15].
The economic condition of local communities (f 2 ) 0.35692 1st The socio-economic factor is significantly correlated with project redevelopment as the economic condition can increase redevelopment brings [25,28]. Accessibility to public transport (f 3 ) 0.21092 3rd Accessibility of the project site is the key determinant for project redevelopment [15].
Type of land use (f 4 ) 0.21555 2nd Type of land use is one of the most important factors affecting project redevelopment as it can affect property values [15,28].
Comfortability (f 5 ) 0.03176 5th Comfortability of the building such as control and indoor quality is important for sustainable project redevelopment [27,32].

Empirical Validation
The most valuable alternative for redeveloping the abandoned airport to improve its economical operational performance was identified based on value-based decision making; a study also confirmed the applicability of value-based decision in enhancing the sustainable performance of buildings [21] [A1]. Empirical validation aims to validate the acceptance of value-based decision making in the industry. An interview session was carried out with an expert who has an industrial background and has expertise in construction project management, value management, and real estate development.
According to the expert, the result of a transportation hub as the most valuable alternative for redeveloping the abandoned airport is accepted. He agrees that among the three alternatives, the transportation hub will be the most valuable alternative because it serves the same function as the abandoned airport which provides transportation services to the local communities. Hence, the initial cost for developing the transportation hub will be lower as compared to the hospital. In addition to this, the expert suggested that the criteria of cost can be divided into two, initial cost and life cycle cost, to enhance the value-based decision-making model [18]. In short, the value-based decision-making model is accepted to be adopted in the construction industry to help the stakeholders to make a decision based on the value of the properties [48].

Conclusions
To implement the value-based decision for redeveloping the transportation facilities, the function needs to be compared with the cost of each alternative for the redevelopment. Based on the research, an abandoned airport was chosen to validate the process to select the best value alternative for redeveloping the transportation facilities by considering the criteria of cost and function through the Analytical Hierarchy Process (AHP) Model. The value-based decision helps in enhancing the selection of choices by the project stakeholders. It should be noted that the result depends on the criteria of function and cost found in the preliminary survey and maximises the profit gained from the development by selecting the alternatives with the lowest cost while maintaining the intended function and quality. In addition, the background of research methodology for value-based decision making is outlined, which consists of value-based analysis and multi-criteria analysis. In the value-based analysis, the function of the alternative is divided by its cost. However, in multicriteria decision making, the criteria of function and cost need to be compared to each other to obtain the value for each alternative. In short, the value-based decision-making model was successfully developed from the research. The reliability of the model was validated by an expert and is accepted to be used in the construction industry. In this research, the best-value alternative is selected by averaging the results from each potential decision-maker. However, to improve value-based decision making, mutual agreement among the decision-makers shall be achieved. Hence, future research is required on the selection of the alternatives based on the negotiation support system.