Model optymalizacji czasuwymiany floty. Analiza porównawcza flot miejskiego transportu publicznego z zastosowaniem symulacji Monte Carlo

[Otro] W niniejszej pracy przedstawiono analiz¿ kosztów pracy i utrzymania flot transportowych w dwóch krajach: Hiszpanii i Brazylii. Dla celów analizy, zaproponowano model optymalizacji stanowi¿cy po¿¿czenie tradycyjnej Analizy Kosztów Cyklu ¿ycia (LCC) oraz modelu symulacji Monte Carlo. wyniki potwierdzi¿y trafno¿¿ modelu oraz pokaza¿y, ¿e koszty ponoszone w przypadku floty brazylijskiej by¿y ni¿sze. Zaproponowany model mo¿e znale¿¿ zastosowanie zarówno w praktyce jak i w dalszych badaniach.[EN] This paper presents a comparative analysis of operation and maintenance costs of the transport fleets in two countries: Spain and Brazil. For this analysis, the research proposed an optimization model which is a combination of the traditional Life Cycle Cost Analysis methodology (LCC) and simulation model Monte Carlo. The results indicated the successful of model and show the lower cost in the Brazilian fleet. The evidences may be useful for other practices and researches.Macian Martinez, V.; Tormos, B.; De Sa-Riechi, JL. (2017). Time Replacement Optimization Model: Comparative Analysis of Urban Transport Fleets Using Monte Carlo Simulation. Eksploatacja i Niezawodnosc - Maintenance and Reliability. 19(2):151-157. doi:10.17531/ein.2017.2.1S15115719

Optimal fleet replacement: A case study on a Spanish urban transport fleet

[EN] Optimizing the average annual cost of a bus fleet has become an increasing concern in transport companies management around the world. Nowadays, there are many tools available to assist managerial decisions, and one of the most used is the cost analysis of the life cycle of an asset, known as ``life cycle cost¿¿. Characterized by performing deterministic analysis of the situation, it allows the administration to evaluate the process of fleet replacement but is limited by not contemplating certain intrinsic variations related to vehicles and for disregarding variables related to exigencies of fleet use. The main purpose of this study is to develop a combined model of support to asset management based in the association of the life cycle cost tool and the mathematical model of Monte Carlo simulation, by performing a stochastic analysis considering both age and average annual mileage for optimum vehicle replacement. The utilized method was applied in a Spanish urban transport fleet, and the results indicate that the use of the stochastic model was more effective than the use of the deterministic model.De Sa-Riechi, JL.; Macian Martinez, V.; Tormos, B.; Avila, C. (2017). Optimal fleet replacement: A case study on a Spanish urban transport fleet. Journal of the Operational Research Society. 68(8):886-894. doi:10.1057/s41274-017-0236-1S886894688Avila da S., C. R., & Beck, A. T. (2015). New method for efficient Monte Carlo–Neumann solution of linear stochastic systems. Probabilistic Engineering Mechanics, 40, 90-96. doi:10.1016/j.probengmech.2015.02.006Boudart, J., & Figliozzi, M. (2012). Key Variables Affecting Decisions of Bus Replacement Age and Total Costs. Transportation Research Record: Journal of the Transportation Research Board, 2274(1), 109-113. doi:10.3141/2274-12Collan, M., & Liu, S. (2003). Fuzzy logic and intelligent agents: towards the next step of capital budgeting decision support. Industrial Management & Data Systems, 103(6), 410-422. doi:10.1108/02635570310479981Erol, I., & Ferrell, W. G. (2003). A methodology for selection problems with multiple, conflicting objectives and both qualitative and quantitative criteria. International Journal of Production Economics, 86(3), 187-199. doi:10.1016/s0925-5273(03)00049-5Feng, W., & Figliozzi, M. (2013). An economic and technological analysis of the key factors affecting the competitiveness of electric commercial vehicles: A case study from the USA market. Transportation Research Part C: Emerging Technologies, 26, 135-145. doi:10.1016/j.trc.2012.06.007Khasnabis, S., Alsaidi, E., & Ellis, R. D. (2002). Optimal Allocation of Resources To Meet Transit Fleet Requirements. Journal of Transportation Engineering, 128(6), 509-518. doi:10.1061/(asce)0733-947x(2002)128:6(509)Keles, P., & Hartman, J. C. (2004). CASE STUDY: BUS FLEET REPLACEMENT. The Engineering Economist, 49(3), 253-278. doi:10.1080/0013791049049895

Holographic Symmetry-Breaking Phases in AdS3_3/CFT2_2

In this note we study the symmetry-breaking phases of 3D gravity coupled to matter. In particular, we consider black holes with scalar hair as a model of symmetry-breaking phases of a strongly coupled 1+1 dimensional CFT. In the case of a discrete symmetry, we show that these theories admit metastable phases of broken symmetry and study the thermodynamics of these phases. We also demonstrate that the 3D Einstein-Maxwell theory shows continuous symmetry breaking at low temperature. The apparent contradiction with the Coleman-Mermin-Wagner theorem is discussed.Comment: 15 pages, 7 figur

The implications of green employment: Making a just transition in ASEAN

The transition to an ecologically sustainable economy is and will create significant changes in the world of work. These changes will include the creation of new green jobs and new industries, minor to major changes in existing jobs and the phase-out of some jobs in carbon-intensive activities. A just transition ensures that while working towards a more ecologically sound economy, countries also plan for positive outcomes for those communities and people negatively affected by our global efforts to decarbonise. Identifying and implementing a country-specific policy mix for a just transition is an emerging challenge for nations. This paper constructs a policy framework for supporting the greening of employment and a just transition. The resulting policy framework is then used to assess policy readiness for promoting green jobs and a just transition across the Association of Southeast Asian Nations (ASEAN). The assessment highlights the current state of policy for supporting green jobs, green skills and just transition planning, as well as the significant challenges in identifying and implementing policy settings to support green jobs and a just transition