7 results
Search Results
Now showing 1 - 7 of 7
Master Thesis Irak'ta Petrol ve Gaz İşleme Tesisleri için İnşaat Projelerinin Risk Değerlendirmesi(2021) Dawood, Muhanned Samır Dawood; Aminbakhsh, SamanPetrol ve gaz, en önemli ekonomik kaynaklardan biridir ve Irak'taki doğal rezervlerin ana arteri olarak kabul edilmektedir. Bu tür rezervlerle ilişkili işleme tesislerinin inşasında yer alan şirketler ve kurumlar, küresel ekonomide çok önemli bir role sahiptir. Öte yandan, Irak'ın sermaye bütçesi büyük ölçüde petrolun gelirlerinin oranına bağlıdır. Bu bağlamda, birçok araştırmacı, petrol ve gaz işleme tesisleri ile ilgili olan inşaat projeleri ile ilgili riskleri belirlemeye ve analiz etmeye çalışmış zaman, maliyet ve kalite gibi kritik başarı faktörleri üzerindeki etkilerin ortadan kaldirmal için çeşitli yöntemler ve pratik planlar önermişlerdir. Bu çalışmanın amacı, Irak'ın petrol ve gaz sektöründeki inşaat projelerinin ana hedefleri arasında istenen dengeyi tehdit eden risklerin benzer şekilde belirlenmesidir. Bu amaç için, literatür taramasının bulguları, akademik çevrelerden, profesyonellerden ve karar alma otoritelerinden ampirik veriler toplamak için bilimsel alanda yaygın olarak atıfta bulunulan 70 risk öğesini içeren çevrimiçi bir anket geliştirmek için kullanılır. Katılımcılar, Irak'ın Petrol Bakanlığı, Kuveyt Enerji, Bağdat Üniversitesi, Kerbala ve Al-Dorra rafinerileri gibi farklı devletin kurumları ve sivil toplumun kuruluşları ve / veya şirketlerinden seçilir. 143 uzman ve risk derecelendirmelerine ilişkin genel bilgiler beşli Likert ölçeği kullanılarak derlenmiştir. Sekiz risk kategorisi altında gruplandırılarak, risk faktörlerinin her biri için olasılık düzeyi ve etki belirlenir. Yanıt verenlerden toplanan verilere dayanarak, tanımlanan riskleri değerlendirmek ve sıralamak için risk matrisleri geliştirilir; bununla birlikte, ilişkili risk yanıtları burada en yüksek on faktör için önerilmektedir. Toplanan yanıtların istatistiksel analizi için SPSS ve Microsoft Excel programları kullanılmış ve verilerin tutarlılığı Cronbach's Alpha güvenirlik katsayısı kullanılarak doğrulanmıştır. Sonuçlar, projelerin başarısını dolaylı olarak etkileyebilecek en önemli risk unsurlarının, 'Küresel petrol ve gaz fiyatlarında istikrarsızlık' ve 'işgücüne yapılan ödemelerde gecikme' olduğuna işaret ediyor.Article Citation - WoS: 2Citation - Scopus: 2Optimizing Three-Dimensional Trade-Off Problem of Time-Cost Over Multi-Mode Projects With Generalized Logic(Mdpi, 2024) Aminbakhsh, Saman; Abdulsattar, Abdulrahman M.Clients typically tend to aim for reasonable prices, minimum possible makespans, and the best quality for the construction projects that they engage in. Evidently, weighing the available offers and coming up with an optimal decision can pose challenges for the decision makers. In this regard, the generation of a tool that helps decision makers strike a proper balance among the conflicting project objectives (i.e., time, cost, and quality) is imperative. To this end, this study proposes a method which assists in the selection of the best compromise choices among the options available for each of the project activities. In addition to the time and cost, the proposed method is designed to bring the quality aspect into the equation as well. To quantify the quality, a value referring to the weighted importance and performance of each activity is used. The proposed method is based on a modified multi-objective genetic algorithm (GA) that incorporates the domination concept for the selection of the best solutions out of the potential candidates. The GA-based method is capable of handling an unlimited number of precedence relationships for each activity, and above all, it is able to capture and unravel any type of logical relationship. This very feature significantly improves the practical relevance of this research, as the parallelization of activities is a common practice in real-life projects. Planners benefit from the various types of relationships (i.e., Start to Start, Start to Finish, Finish to Start, and Finish to Finish), and the concept of lag time frequently introduces parallelization into the network. Overlapped activities, in turn, help reduce the unwanted idle times and speed up the project significantly. Accordingly, in order to demonstrate the application and effectiveness of the proposed model, it has been used in the solution of four time-cost-quality (TCQ) trade-off problems, three of which are generated within the context of this paper. The practiced instances include a small benchmark TCQT problem with 18 activities taken from the literature in addition to more complex 29- and 63-activity TCQTPs produced herein based on benchmark time-cost trade-off problems. The performance of the presented approach is ultimately examined over a large-scale, real-case construction project with over four hundred activities and generalized logic in an unprecedented attempt to validate a model in the realm of TCQTPs. The successful results of the experiments reveal the effectiveness of the proposed model and corroborate the feasibility of its application by the planners amidst arduous decision-making processes.Article Citation - WoS: 31Citation - Scopus: 39A Transformative Solution for Construction Safety: Blockchain-Based System for Accident Information Management(Elsevier, 2023) Ahmadisheykhsarmast, Salar; Aminbakhsh, Saman; Sonmez, Rifat; Uysal, FurkanEffective management of accident information is a crucial component of safety management within the construction industry, as it reflects the safety performance of the company and allows them to identify the root causes of accidents and prevent similar accidents in the future. However, existing safety information systems provide self-owned, isolated, and centralized environments and fail to present a secure, transparent, and trustworthy platform for monitoring and management of accident information. To address these issues, this paper presents a novel decentralized blockchain-based system for accident/incident information management of construction projects. The proposed system leverages the benefits and advantages of blockchain, smart contracts, and decentralized IPFS storage to address the security transparency, tampering, and trustworthiness issues of the conventional approaches. The proposed system is simulated by using real-world construction accident data to demonstrate how blockchain technology can provide a novel solution to assure security, transparency, authenticity, availability, and immutability of the accident/incident data for improving safety management.Article Citation - Scopus: 1An Enhanced Guided Stochastic Search With Repair Deceleration Mechanism for Very High-Dimensional Optimization Problems of Steel Double-Layer Grids(Springer, 2024) Azad, Saeid Kazemzadeh; Aminbakhsh, Saman; Gandomi, Amir H.Finding reasonably good solutions using a fewer number of objective function evaluations has long been recognized as a good attribute of an optimization algorithm. This becomes more important, especially when dealing with very high-dimensional optimization problems, since contemporary algorithms often need a high number of iterations to converge. Furthermore, the excessive computational effort required to handle the large number of design variables involved in the optimization of large-scale steel double-layer grids with complex configurations is perceived as the main challenge for contemporary structural optimization techniques. This paper aims to enhance the convergence properties of the standard guided stochastic search (GSS) algorithm to handle computationally expensive and very high-dimensional optimization problems of steel double-layer grids. To this end, a repair deceleration mechanism (RDM) is proposed, and its efficiency is evaluated through challenging test examples of steel double-layer grids. First, parameter tuning based on rigorous analyses of two preliminary test instances is performed. Next, the usefulness of the proposed RDM is further investigated through two very high-dimensional instances of steel double-layer grids, namely a 21,212-member free-form double-layer grid, and a 25,514-member double-layer multi-dome, with 21,212 and 25,514 design variables, respectively. The obtained numerical results indicate that the proposed RDM can significantly enhance the convergence rate of the GSS algorithm, rendering it an efficient tool to handle very high-dimensional sizing optimization problems.Master Thesis Türk İnşaat Sektöründe 3B Baski Teknolojisinin Benimsenmesini Etkileyen Ana Etkenler ve Engeller(2025) Latifiilkhechi, Leva; Aminbakhsh, Saman; Akçay, Emre CanerBu çalışmada, Türk inşaat sektöründe 3B baskı teknolojisinin benimsenmesini etkileyen temel faktörler incelenmiştir. Bu doğrultuda, kapsamlı bir literatür taraması sonucunda 27 teşvik edici ve 19 engelleyici faktör belirlenmiş olup, bu faktörlerin değerlendirmesi 106 uzmandan oluşan bir anket çalışması ile yapılmıştır. Bu faktörlerin önemi, Göreceli Önem İndeksi (GÖİ) kullanılarak değerlendirilmiş ve ardından Analitik Hiyerarşi Prosesi (AHP) ile faktörlerin önem düzeyleri belirlenmiştir. 3B baskı teknolojisinin daha hızlı inşaat, iş kazalarının azalması, enerji verimliliğinin artması ve karmaşık tasarımların daha kolay uygulanması gibi avantajlar sunduğu görülse de, bu teknolojinin benimsenmesini engelleyen başlıca zorluklar arasında 3B Beton Baskı için yeterli düzenlemelerin ve yapı kodlarının eksikliği, büyük ölçekli uygulamalar konusunda sınırlı bilgi ve yalıtım malzemelerinin yetersizliği yer almaktadır. Araştırma sonuçları, malzeme israfını azaltma ve daha fazla özelleştirme imkânı sağlama gibi faktörlerin 3B baskının inşaat sektöründe benimsenmesinde en önemli etmen olduğunu, gözetim maliyetlerinin azaltılmasının ise en az önemli teşvik edici faktör olduğunu ortaya koymuştur. Diğer yandan, siber güvenlik riskleri, potansiyel iş kayıpları ve basılı yapıların katmanlı ve pürüzlü yüzeyleri, en kritik engeller olarak belirlenmiştir. Bu araştırma, 3B baskı teknolojisinin inşaat sektörüne entegrasyonunun artırılması için bu etmenlerin ve engellerin hedefe yönelik stratejilerle ele alınması gerektiğini vurgulamaktadır.Article Semiautomated Delay Analysis Method Selection for Construction Projects: A Rule-Based Approach(ASCE-Amer Soc Civil Engineers, 2026) Agar, Mehmet; Sonmez, Rifat; Aminbakhsh, SamanGiven the availability of various delay analysis methods, each yielding different results, the proper selection of an appropriate methodology is of paramount importance. Despite the necessity for automation to resolve delay conflicts, the current literature lacks an automated approach to assist contractors and project owners in reaching a consensus on selecting the most suitable delay analysis method without requiring a third party. Hence, to bridge the gap between theoretical research and practical application in achieving an automated delay analysis method, a novel rule-based expert system has been proposed. A structured, multiphase methodology that includes a review of existing methods, identification of key facts, determination of facts and expert rules, development of a forward chaining inference engine, and validation stages is used. Five real-world case examples and the decisions of experts for 15 hypothetical case examples are used for validation. The case examples demonstrate that the system can successfully automate the selection of the most appropriate delay analysis method and support a transparent, systematic approach to managing delays in construction projects. Furthermore, the system can foster consensus among project stakeholders during the selection of a delay analysis method and has the potential to contribute to the resolution of delay disputes.Article Citation - WoS: 3Citation - Scopus: 3Ε-Constraint Procedures for Pareto Front Optimization of Large Size Discrete Time/Cost Trade-Off Problem(Elsevier, 2025) Aminbakhsh, Saman; Sonmez, Rifat; Atan, TankutThe discrete time/cost trade-off problem (DTCTP) optimizes the project duration and/or cost while considering the trade-off between activity durations and their direct costs. The complete and non-dominated time-cost profile over the set of feasible project durations is achieved within the framework of Pareto front problem. Despite the importance of Pareto front optimization in project and portfolio management, exact procedures have achieved very limited success in solving the problem for large size instances. This study develops exact procedures based on combinations of mixed-integer linear programming (MILP), epsilon-constraint method, network and problem reduction techniques, and present new bounding strategies to solve the Pareto problem for large size instances. This study also provides new large size benchmark problem instances aiming to represent the size of real-life projects for the DTCTP. The new instances, therefore, are generated to include up to 990 activities and nine execution modes. Computational experiments reveal that the procedures presented herein can remarkably outperform the state-of-the-art exact methods. The new exact procedures enabled obtaining the optimal Pareto front for instances with serial networks that include more than 200 activities for the first time.