Development and Evaluation of Hull-form Stochastic Optimization Methods for Resistance and Operability

2015 ◽  
Author(s):  
Matteo Diez ◽  
Emilio F. Campana ◽  
Frederick Stern

Hull-form stochastic optimization methods are developed and evaluated for resistance reduction and operability increase, addressing stochastic sea state and operations. The cost/benefit analysis of the design-optimization procedure is presented, by comparison of four hierarchical problems, from stochastic most general to deterministic least general. The parent hull is a 100 m Delft catamaran, with geometrical constraints for maximum variation of length, beam, draft and displacement. Problem 1 is used as a benchmark for the evaluation of the other problems. It is as a multi-objective stochastic optimization for resistance and operability, considering stochastic sea state and speed, but limited to head waves. Problem 2 is a multi-objective stochastic optimization for resistance and motions at fixed sea state and speed. Problem 3 is a multi-objective deterministic optimization for resistance and motions using a single regular wave at fixed speed. Problem 4 is a single-objective deterministic optimization for calm-water resistance at fixed speed. The design optimization is based on hull modifications by the Karhunen-Loève expansion of a free-form deformation space, URANS simulations, regular wave approximations for irregular wave, metamodels and multi-objective particle swarm. The design optimization achieves an 8.7, 23, 53, and 10% average improvement for problems 1, 2, 3, and 4, respectively. Comparing to problem 1, problem 2, 3, 4 optimized designs have average performances 1, 2.1 and 1.7% worse, respectively. The most efficient problem, from computational cost/benefit analysis, is problem 3. Nevertheless, problem 1 is needed in order to evaluate and compare the stochastic performance of the design, and assess the optimization cost/benefit.

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Mohammad Khodabakhshi ◽  
Mehdi Ahmadi

Purpose The paper aims to present an approach to cost-benefit analysis with stochastic data. Determining the type and the values of alternative’s factors are probably the most important issue in this approach. Therefore, in the proposed approach, a competitive advantage model was built to measure the values of alternative’s factors. Then, a satisfactory cost-benefit analysis model with random data was proposed to evaluate the alternatives. The cost-benefit analysis of each alternative was carried out to obtain the real and satisfactory cost-benefit of the decision-maker. Design/methodology/approach This paper is orientationally expressed as a mathematical problem in which the optimization problem needs to analyze the approach. This paper is written based on uncertainty linear optimization. Optimization under uncertainty refers to this branch of optimization where there are uncertainties involved in the data or the model and is popularly known as stochastic optimization problems. Findings As was seen in the purpose part, in this paper, an approach is presented to cost-benefit analysis by the use of competitive advantage with stochastic data. In this regards, a stochastic optimization problem to assess competitive advantage is proposed. This optimization problem recognizes the values of alternative’s factors which is the most important step in cost-benefit analysis. An optimization problem is proposed to cost benefit analysis, as well. Practical implications To investigate different aspects of the proposed approach, a case study with random data of 21 economic projects was considered. Originality/value Cost–benefit analysis is a systematic approach to estimating the strengths and weaknesses of alternatives used to determine options which provide the best approach to achieving benefits while preserving savings. Cost–benefit analysis is related to cost-effectiveness analysis. Benefits and costs are expressed in monetary terms and are adjusted for the time value of money; all flows of benefits and costs over time are expressed on a common basis in terms of their net present value, regardless of whether they are incurred at different times. As seen the paper using competitive advantage tries to determine the values of alternative’s factor. As competitive advantage model analyze the advantages and disadvantages of alternatives, this paper by the use of this idea tries to determine the costs and benefits. Two stochastic optimization problems in the middle of this approach are proposed, which assess competitive advantage and cost–benefit analysis, respectively.


2010 ◽  
Vol 16 (1) ◽  
pp. 5-24 ◽  
Author(s):  
Willem Karel M. Brauers ◽  
Edmundas Kazimieras Zavadskas

The countries of Central and Eastern Europe moved from a previously centrally planned economy to a modern transition economy with strong market aspects. This paper proposes project management as an answer to this transition. Traditional Cost‐Benefit analysis does not respond to this purpose. Indeed Cost‐Benefit analysis is only interested in one specific project and not in a competition between projects. In addition all goals (objectives) have to be translated into money terms, leading sometimes to immoral consequences. On the contrary Multi‐Objective Optimization takes care of different objectives, whereas the objectives keep their own units. However different methods exist for the application of Multi‐Objective Optimization. The authors tested them after their robustness resulting in seven necessary conditions. MOORA (Multi‐Objective Optimization by Ratio analysis) and MULTIMOORA (MOORA plus Full Multiplicative Form), assisted by Ameliorated Nominal Group and Delphi Techniques, satisfy the seven conditions, although in a theoretical way. A simulation exercise illustrates the use of these methods, ideals to be strived for as much as possible. Santrauka Centrinės ir rytų Europos šalys perėjo iš anksčiau centralizuotai planuojamos ūkinės sistemos į šiuolaikinę pereinamąją ūkinę sistemą, kuriai būdingi ryškūs rinkos požymiai. Šiame straipsnyje siūloma projektų vadyba kaip atsakas į perėjimą. Įprastinė kainos ir naudos analizė tam tikslui yra netinkama. Be viso to, kainos ir naudos analizėje neatsižvelgiama į kiekvieną atskirai paimtą projektą bei į konkurenciją tarp tų projektų. Visi tikslai turi būti pakeisti piniginėmis vertėmis. Del to kartais kyla nepageidaujamų pasėkmių. Priešingai tam daugiatikslė optimizacija atsižvelgia į skirtingus tikslus, išsaugant tikslams būdingus mato vienetus. Yra daug įvairių daugiatikslės optimizacijos metodų. Autoriai patikrino jų stipriasias savybęs pagal septynias būtinasias sąlygas. MOORA (daugiatikslė optimizacija santykių dydžių analizės pagrindu) ir MULTIMOORA (MOORA plius pilnoji sandaugos forma), apimanti patobulintą normaliųjų grupių ir Delphi būdus, geriausiai atitinka septynias būtinąsiąs sąlygas taip pat ir teoriniu lygmeniu. Pavyzdžio modelis iliustruoja šiu metodu taikymą, idealai buvo pasiekti tiek, kiek galima.


2011 ◽  
pp. 57-78
Author(s):  
I. Pilipenko

The paper analyzes shortcomings of economic impact studies based mainly on input- output models that are often employed in Russia as well as abroad. Using studies about sport events in the USA and Olympic Games that took place during the last 30 years we reveal advantages of the cost-benefit analysis approach in obtaining unbiased assessments of public investments efficiency; the step-by-step method of cost-benefit analysis is presented in the paper as well. We employ the project of Sochi-2014 Winter Olympic and Paralympic Games in Russia to evaluate its efficiency using cost-benefit analysis for five accounts (areas of impact), namely government, households, environment, economic development, and social development, and calculate the net present value of the project taking into account its possible alternatives. In conclusion we suggest several policy directions that would enhance public investment efficiency within the Sochi-2014 Olympics.


2007 ◽  
pp. 70-84 ◽  
Author(s):  
E. Demidova

This article analyzes definitions and the role of hostile takeovers at the Russian and European markets for corporate control. It develops the methodology of assessing the efficiency of anti-takeover defenses adapted to the conditions of the Russian market. The paper uses the cost-benefit analysis, where the costs and benefits of the pre-bid and post-bid defenses are compared.


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