Forecasting and Forecast Combination in Airline Revenue Management Applications

Predicting a variable for a future point in time helps planning for unknown future situations and is common practice in many areas such as economics, finance, manufacturing, weather and natural sciences. This paper investigates and compares approaches to forecasting and forecast combination that can be applied to service industry in general and to airline industry in particular. Furthermore, possibilities to include additionally available data like passenger-based information are discussed

Building information modeling (BIM) and green building index (GBI) assessment framework for non-residential new construction building (NRNC)

The global construction industry endorsed Building Information Modeling (BIM) and its many advantages. However, despite this endorsement, BIM still failed to attract Malaysian companies to use BIM in green building assessment, especially for the assessment of Green Building Index (GBI), and maintain GBI certification during building occupancy using BIM features. The main issue of utilizing BIM as a GBI assessment tool is the applicability of BIM Tools to digitalize GBI credit by design team, which results in the digitization of GBI criteria into BIM Model. This study aims to identify common components related to the capability of BIM to digitalize and assess GBI criteria. These components include BIM uses and tools and GBI criteria and processes. This study applied quantitative and qualitative approaches to collect data. The quantitative approach used questionnaires, which were distributed to 900 GBI members, i.e. GBI certifiers and facilitators. The survey generated a response rate of 32% during eight months of data collection. The results were analyzed using SPSS and SmartPLS. Four model categories were identified, namely, BIM uses, BIM tools, GBI criteria and GBI certification process. These categories were used to assess the BIM–GBI framework. The results obtained from the questionnaire showed that only 16 BIM uses must be included in the BIM execution plan of the GBI project for assessment purposes. The results also showed that the BIM tools present different levels of effect on the GBI criteria. The capability of BIM to assess GBI could be stronger in the design assessment (DA) than in the operation assessment, which supports the suggested BIM–GBI assessment framework. The second data collection was conducted through a focus group interview with BIM and GBI experts. Two interview sessions were conducted. Results show that the assessment method has a significant correlation in the BIM– GBI framework. The following categories were identified for the BIM assessment framework: BIM uses, BIM tools, and control, which were based on the GBI criteria for scoring and certification. Findings from the BIM and GBI assessment method framework show that GBI credits can be digitalized using different BIM uses directly and indirectly assessed by BIM tools for each GBI credit in both GBI assessment process. Based on the qualitative result of this research showed that BIM can help the design team to achieve 55% point in design assessment (DA) only and this helps the building to achieve GBI certification in level 4 of certified rating. On the other hand, 45% points of GBI credits can be digitals in completion and verification assessment (CVA). The framework provides a guide for the design team and facility management in digitalizing and assessing GBI criteria using BIM application during design assessment (DA) and completion and verification assessment (CVA) for new nonresidential constructions. The framework also offers and provides insights that will enable designers to understand the relationship between BIM and GBI criteria, which will contribute to BIM integration in Stage 3 and automate GBI assessment for the Malaysian construction industry

Fuzzy gravity approach for determinants of exports

Purpose: The present study proposes the fuzzy gravity model approach to examine the main factors that affect the export volume of Turkey and whether the European Union Customs Union (EUCU) membership affected the export of it. Design/Methodology/Approach: A fuzzy approach was developed for the gravity model by using these variables. The dependent variable was the export volume of Turkey to 204 countries throughout the whole world, and the explanatory variables were the gross domestic product (GDP) of the countries that are subject to export and their distances to Turkey (dij), populations, whether the seaway transport was possible, and the membership to the EUCU. The last two items were added as dummy variables in the model. Findings: The results showed that gross domestic product (GDP) of the country which Turkey exports to, its being a member of the EUCU, and its population affected the export volume of Turkey positively. However, the distance of the target country to Turkey had a negative effect. The coefficient of distance variable was found to be negative fuzzy and ones of the seaway was fully fuzzy. However, when seaway variable was taken together with distance, it was positive fuzzy, which showed the positive effect of the opportunity of transportation by sea in long distances on export volume. Practical Implications: It is thought that the policies to be established based on these findings will be beneficial in improving the country's exports. Other available fuzzy regression approaches may be tried in future studies to obtain a fuzzy model. In addition, the import or foreign trade structure of Turkey may be dealt with the same approach. Originality/Value: In this study the fuzzy gravity model approach was used as a novelty, which was different from the methods in the literature, because the gravity model is criticized sometimes that its theoretical basis is weak and the relations between dependent variables and explanatory variables are not adequately clear.peer-reviewe

Nuclear Power Plant Operator Reliability Research Based on Fuzzy Math

This paper makes use of the concept and theory of fuzzy number in fuzzy mathematics, to research for the response time of operator in accident of Chinese nuclear power plant. Through the quantitative analysis for the performance shape factors (PSFs) which influence the response time of operators, the formula of the operator response time is obtained based on the possibilistic fuzzy linear regression model which is used for the first time in this kind of research. The research result shows that the correct research method can be achieved through the analysis of the information from a small sample. This method breaks through the traditional research method and can be used not only for the reference to the safe operation of nuclear power plant, but also in other areas

Outliers detection method in fuzzy regression

In the article we propose a method of outliers identification in fuzzy regression. The outliers which occur in the sample may have an important influence on the form of regression equation. That is the reason of a great scientific interest in this issue. Presented method is an equivalent of the method of finding outliers basing on the studentized residuals distribution. To identify outliers there are regression models constructed with an additional explanatory variable for each observation. Next, the significance of fuzzy regression coefficient is analysed considering the additional explanatory variable. The illustrating examples are presented.fuzzy regression, outliers, possibility theory