INCREASE IN THE FUEL EFFICIENCY OF A DIESEL ENGINE BY DISCONNECTING SOME OF ITS CYLINDERS

In fuel economy, a rising level of interest in heavy duty diesel engines that industry has witnessed over the last few years continues to go up and this is not likely to change. Lowering the fuel consumption of all internal combustion engines remains a priority for years to come, driven by economic, legislative, and environmental reasons. According to statistics, the share of operating expenses to ensure transport operations in industrial production is 15-20%, wherein 16-30% of the total volume of transport operations concerns a car, tractor, and trailer. During transport operations, the engine load by the torque, in most cases, does not exceed 40-50%. The paper investigates the increase in fuel efficiency of cars and tractors by disconnecting some of the engine cylinders operated in low-load and idling modes. The research has led to the establishment of the theoretical dependencies between the effective power, engine efficiency, mass of the transported cargo, speed of the car (tractor) and the number of disconnected engine cylinders. Results of experiments suggest the interdependencies of the performance parameters of the car (tractor) when disconnecting some of the engine cylinders. It has also been established that the maximum reduction in the hourly fuel consumption occurs in the idling mode while it decreases along with an increase in the load

Impact of Forest Tending on Structural Characteristics of Coppices in Lika

Istraživanjem smo ustanovili strukturne elemente različitih tipo va panjača u Lici, pet godina nakon njege proredom. Panjače ličkog područja karaktezira nizak stupanj provedenih radova njege, te neotvorenost šumskim prometnicama. Prepoznatljive su četri morfološka tipa: prijelazne panjače, tipične panjače, panjače u regresiji i zašikarene panjače. Terenska mjerenja obavlje na su na pet trajnih pokusnih ploha. Na kraju vegetacijskog razdoblja 2007. go dine na tim su plohama izmjereni strukturni elementi sastojina. Obavljena je totalna klupaža svih stabala po debljinskim stupnjevima, etažama, vrstama drveća i po podrijetlu (generativno, vegetativno), snimljeni su uzorci visina i uzeti izvrtci za određivanje prirasta, posebno za stabla iz sjemena i iz panja. Stabla iz sjemena imaju značajno veće vrijednosti strukturnih elemenata. S obzirom na to da stabla iz sjemena pokazuju veću produktivnost i vitalnost, jasna je potreba njihova uzgojnog favoriziranja, neovisno o kojemu se tipu panjače radi. Intenziteti i volumeni iduće prorede ovisit će o prosječnom dobnom volumnom prirastu i dobi sastojine, te o ukupnom volumenu sastojina na kraju turnusa. Radi poveća nja temeljnog volumena te stabilnosti sastojina, volumen iduće prorede trebao bi biti 40–45 % desetgodišnjeg tečajnog volumnog prirasta.Our research determined structural elements of different coppice types in Lika five years after they were tended with thinning. Coppices in the region of Lika are characterized by a low degree of applied tending operations and inaccessibility caused by the lack of forest roads. Four morphological types can be differentiated: transitional coppices, typical coppices, coppices in regression and thickets. Field measurements were undertaken in five permanent sample plots. Structural stand elements in these plots were measured at the end of the vegetation period in 2007. Total measurements of breast diameters of all trees were performed by diameter class, storey, tree species and origin (generative, vegetative), and height samples were recorded and increment cores taken for increment assessment separately for seed trees and sprouts from stumps. Seed trees show significantly higher values of structural elements. The fact that seed trees manifest higher productivity and vitality clearly indicates that they should be silviculturally favored regardless of coppice type. Intensities and volumes of the next thinning operation will depend on the average age volume increment and stand age, as well as on the total stand volume at the end of the thinning cycle. In order to increase the basic volume and achieve stand stability, the volume of the next thinning operation should amount to 40–45 % of the ten-year current volume increment

Un modelo integrado para el enrutamiento de aeronaves y la programación de la tripulación: Relajación lagrangiana y algoritmo metaheurístico

[EN] Airline optimization is a significant problem in recent researches and airline industryl as it can determine the level of service, profit and competition status of the airline. Aircraft and crew are expensive resources that need efficient utilization. This paper focuses simultaneously on two major issues including aircraft maintenance routing and crew scheduling. Several key issues such as aircraft replacement, fairly night flights assignment and long-life aircrafts are considered in this model. We used the flight hours as a new framework to control aircraft maintenance. At first, an integrated mathematical model for aircraft routing and crew scheduling problems is developed with the aim of cost minimization. Then, Lagrangian relaxation and Particle Swarm Optimization algorithm (PSO) are used as the solution techniques. To evaluate the efficiency of solution approaches, model is solved with different numerical examples in small, medium and large sizes and compared with GAMS output. The results show that Lagrangian relaxation method provides better solutions comparing to PSO and also has a very small gap to optimum solution.[ES] La optimización de aerolíneas es un problema importante en investigaciones recientes e industria de aerolíneas, ya que puede determinar el nivel de servicio, el beneficio y el estado de competencia de la aerolínea. Las aeronaves y la tripulación son recursos costosos que necesitan una utilización eficiente. Este artículo se centra simultáneamente en dos cuestiones principales, incluyendo el enrutamiento de mantenimiento de aeronaves y la programación de la tripulación. En este modelo se consideran varios temas clave, como el reemplazo de aeronaves, la asignación de vuelos nocturnos y los aviones envejecidos. Usamos las horas de vuelo como un nuevo marco para controlar el mantenimiento de las aeronaves. Al principio, se desarrolla un modelo matemático integrado para el enrutamiento de aeronaves y los problemas de programación de la tripulación con el objetivo de la minimización de costos. A continuación, se utilizan como técnicas de solución la relajación lagran-giana y el algoritmo “Particle Swarm Optimization” (PSO). Para evaluar la eficiencia de los en-foques de la solución, el modelo se resuelve con diferentes ejemplos numéricos en tamaños pequeños, medianos y grandes y se compara con la salida GAMS. Los resultados muestran que el método de relajación lagrangiana proporciona mejores soluciones en comparación con PSO y también tiene una pequeña diferencia para una solución óptimaMirjafari, M.; Rashidi Komijan, A.; Shoja, A. (2020). An integrated model for aircraft routing and crew scheduling: Lagrangian Relaxation and metaheuristic algorithm. WPOM-Working Papers on Operations Management. 11(1):25-38. https://doi.org/10.4995/wpom.v11i1.12891OJS2538111Al-Thani, Nayla Ahmad, Ben Ahmed, Mohamed and Haouari, Mohamed (2016). A model and optimization-based heuristic for the operational aircraft maintenance routing problem, Transportation Research Part C: Emerging Technologies, Volume 72, Pages 29-44. https://doi.org/10.1016/j.trc.2016.09.004Azadeh, A., HosseinabadiFarahani, M., Eivazy, H., Nazari-Shirkouhi, S., &Asadipour, G. (2013). A hybrid meta-heuristic algorithm for optimization of crew scheduling, Applied Soft Computing, Volume 13, Pages 158-164. https://doi.org/10.1016/j.asoc.2012.08.012Barnhart C. and Cohn, A. (2004). Airline schedule planning: Accomplishments and opportunities, Manufacturing & Service Operations Management, 6(1):3-22, 47, 69, 141, 144. https://doi.org/10.1287/msom.1030.0018Basdere, Mehmet and Bilge, Umit (2014). Operational aircraft maintenance routing problem with remaining time consideration, European Journal of Operational Research, Volume 235, Pages 315-328. https://doi.org/10.1016/j.ejor.2013.10.066Bazargan, Massoud (2010). Airline Operations and scheduling second edition, Embry-Riddle Aeronautical University, USA, Ashgate publishing limite.Belien, Jeroen, Demeulemeester, Eric and Brecht (2010). Integrated staffing and scheduling for an aircraft line maintenance problem, HUB RESEARCH PAPER Economics & Management.Ben Ahmed, M., Zeghal Mansour, Farah and Haouari, Mohamed (2018). Robust integrated maintenance aircraft routing and crew pairing, Journal of Air Transport Management, Volume 73, Pages 15-31. https://doi.org/10.1016/j.jairtraman.2018.07.007Ben Ahmed, M., Zeghal Mansour, F., Haouari, M. (2017). A two-level optimization approach for robust aircraft routing and retiming, Computers and Industrial Engineering, Volume 112, Pages 586-594. https://doi.org/10.1016/j.cie.2016.09.021Borndorfer, R., Schelten, U., Schlechte, T., Weider, S. (2006). A column generation approach to airline crew scheduling, Springer Berlin Heidelberg, Pages 343-348. https://doi.org/10.1007/3-540-32539-5_54Clarke, L., E. Johnson, G. Nemhauser, Z. Zhu. (1997). The Aircraft Rotation Problem. Annals of Operations Research, 69, Pages 33-46. https://doi.org/10.1023/A:1018945415148Deveci, Muhammet and ÇetinDemirel, Nihan (2018). Evolutionary algorithms for solving the airline crew pairing problem, Computers & Industrial Engineering, Volume 115, Pages 389-406. https://doi.org/10.1016/j.cie.2017.11.022Dozic, S., Kalic, M. (2015). Three-stage airline fleet planning model, J. Air Transport. Manag, 43, Pages 30-39. https://doi.org/10.1016/j.jairtraman.2015.03.011Eltoukhy, A.E., Chan, F.T., Chung, S. (2017). Airline schedule planning: a review and future directions, Ind. Manag. Data Syst, 117(6), Pages 1201-1243. https://doi.org/10.1108/IMDS-09-2016-0358Feo, T. A., J. F. Bard. (1989). Flight Scheduling and Maintenance Base Planning. Management Science, 35(12), Pages 1415-1432. https://doi.org/10.1287/mnsc.35.12.1415Goffin, J. L. (1977). On the convergence rates of subgradient optimization methods. Math. Programming, 13, Pages 329-347. https://doi.org/10.1007/BF01584346Gopalakrishnan, B., Johnson, E. L (2005). Airline crew scheduling, State-of-the-art. Ann. Oper. Res, 140(1), Pages 305-337. https://doi.org/10.1007/s10479-005-3975-3Held, M. and Karp, R.M. (1970). The Traveling-Salesman Problem and Minimum SpanningTrees. Operations Research, 18, 1138-1162. https://doi.org/10.1287/opre.18.6.1138Held, M. Wolfe, P., Crowder, H. D. (1974). Validation of subgradient optimization, Math. Programming, 6, 62-88. https://doi.org/10.1007/BF01580223Jamili, Amin (2017). A robust mathematical model and heuristic algorithms for integrated aircraft routing and scheduling, with consideration of fleet assignment problem, Journal of Air Transport Management, Volume 58, Pages 21-30. https://doi.org/10.1016/j.jairtraman.2016.08.008Jiang, H., Barnhart, C. (2009) Dynamic airline scheduling, Transport. Sci, 43(3), Pages 336-354. https://doi.org/10.1287/trsc.1090.0269Kasirzadeh, A., Saddoune, M., Soumis, F. (2015). Airline crew scheduling: models, algorhitms and data sets, Euro Journal on Transportation and Logistics, 6(2), Pages 111-137. https://doi.org/10.1007/s13676-015-0080-xLacasse-Guay, E., Desaulniers, G., Soumis, F. (2010). Aircraft routing under different business processes, J. Air Transport. Manag, 16(5), Pages 258-263. https://doi.org/10.1016/j.jairtraman.2010.02.001Muter, İbrahim, Birbil, Ş. İlker, Bülbül, Kerem, Şahin, Güvenç,Yenigün, Hüsnü, Taş,Duygu andTüzün, Dilek (2013). Solving a robust airline crew pairing problem with column generation, Computers & Operations Research, Volume 40, Issue 3, Pages 815-830. https://doi.org/10.1016/j.cor.2010.11.005Saddoune, Mohammed, Desaulniers, Guy, Elhallaoui, Issmail and François Soumis (2011). Integrated airline crew scheduling: A bi-dynamic constraint aggregation method using neighborhoods, European Journal of Operational Research, Volume 212, Pages 445-454. https://doi.org/10.1016/j.ejor.2011.02.009Safaei, Nima and K.S.Jardine, Andrew (2018). Aircraft routing with generalized maintenance constraints, Omega, Volume 80, Pages 111-122. https://doi.org/10.1016/j.omega.2017.08.013Shao Shengzhi (2012). Integrated Aircraft Fleeting, Routing, and Crew Pairing Models and Algorithms for the Airline Industry, Faculty of the Virginia Polytechnic Institute and State University In Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy in Industrial and Systems Engineering.Shao, S., Sherali, H.D., Haouari, M. (2017). A novel model and decomposition approach for the integrated airline fleet assignment, aircraft routing, crew pairing problem, Transport. Sci, 51(1), Pages 233-249. https://doi.org/10.1287/trsc.2015.0623Sherali, H.D., Bish, E.K., Zhu, X. (2006). Airline fleet assignment concepts, models and algorithms, Eur. J. Oper. Res, 172(1), Pages 1-30. https://doi.org/10.1016/j.ejor.2005.01.056Warburg, V., Hansen, T.G., Larsen, A., Norman, H., Andersson, E. (2008). Dynamic airline scheduling: an analysis of potentials of refleeting and retiming, J. Air Transport. Manag. 14(4), Pages 163-167. https://doi.org/10.1016/j.jairtraman.2008.03.004Yan, C. and Kung, J. (2018). 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A novel 3D multilateration sensor using distributed ultrasonic beacons for indoor navigation

Navigation and guidance systems are a critical part of any autonomous vehicle. In this paper, a novel sensor grid using 40 KHz ultrasonic transmitters is presented for adoption in indoor 3D positioning applications. In the proposed technique, a vehicle measures the arrival time of incoming ultrasonic signals and calculates the position without broadcasting to the grid. This system allows for conducting silent or covert operations and can also be used for the simultaneous navigation of a large number of vehicles. The transmitters and receivers employed are first described. Transmission lobe patterns and receiver directionality determine the geometry of transmitter clusters. Range and accuracy of measurements dictate the number of sensors required to navigate in a given volume. Laboratory experiments were performed in which a small array of transmitters was set up and the sensor system was tested for position accuracy. The prototype system is shown to have a 1-sigma position error of about 16 cm, with errors between 7 and 11 cm in the local horizontal coordinates. This research work provides foundations for the future development of ultrasonic navigation sensors for a variety of autonomous vehicle applications

Heavy Vehicle Performance During Recovery From Forced-Flow Urban Freeway Conditions Due To Incidents, Work Zones and Recurring Congestion

Information contained in the Highway Capacity Manual on the influence heavy vehicles have on freeway traffic operations has been based on few field data collection efforts and relied mostly on traffic simulation efforts. In the 2010 Manual heavy vehicle impact is evaluated based on “passenger car equivalent” values for buses, recreational vehicles and trucks. These values were calibrated for relatively uncongested freeway conditions (levels of service A through C) since inadequate field data on heavy vehicle behavior under congested conditions were available. A number of field data collection efforts, that were not included in deriving the passenger car equivalent values used in the Highway Capacity Manual, indicated that heavy vehicle impacts on traffic operations may increase as freeway congestion levels increase and freeways operate under unstable flow conditions. The goal of the present effort was to collect and analyze field data with an emphasis on heavy vehicle behavior under lower speeds and derive passenger car equivalent values under such conditions

Value Relevance of Financial and Non-Financial Information: Evidence from the Gaming Industry

Using financial and non-financial data from casino gaming firms listed in the United States from 1999–2017, we explore two research questions: (1) Is financial information value relevant to financial markets in the casino gaming industry? (2) Does non-financial information have incremental explanatory power over financial information? In general, we find that accounting numbers can explain a firm’s market value and stock returns in the casino gaming industry, except for accounting accruals, which may behave differently compared to other industries. We also find that non-financial information, such as the number of table games, number of slot machines, and their relative proportion, have significant value relevance in explaining market valuation. Our findings contribute to a better understanding of the value relevance of financial and non-financial information in the casino gaming industry. We also provide analysis of firms characterized by these non-financial attributes. Keywords: hospitality, casino, gaming, value relevance, table games, slot machines JEL Code: L83, M19, M4

New Jersey 9-1-1 Consolidation Study: Site Visit Results and Implications for Consolidation

In 1999, the Center for Government Services at Rutgers, The State University of New Jersey completed a study of New Jersey's E9-1-1 system. The study offered a snapshot of the extensive and decentralized network of communications centers that receive incoming calls requesting emergency assistance and that dispatch police, fire, and medical units. In 2005, the New Jersey Office of Management and Budget commissioned the John J. Heldrich Center for Workforce Development at Rutgers University to build on the findings of the 1999 study by exploring ways to improve the efficiency of New Jersey's E9-1-1 system while maximizing the use of available funding.This report is the result of site visits and interviews with officials from 12 PSAPs. The focus of this report is on the current landscape of local operations, funding, staffing, equipment, and technology. In addition, this report identifies issues associated with consolidation, including barriers and opportunities, and presents recommendations for promoting consolidation in New Jersey. It is the third of four deliverables to be produced by the Heldrich Center for the State of New Jersey's 9-1-1 Consolidation Study.Presently, there are over 200 Public Safety Answering Points (PSAPs) and more than 100 enhanced Public Safety Dispatch Points (PSDPs) operating in New Jersey. The central goal of this study is to determine whether a consolidation of PSAPs and PSDPs could reduce costs while maintaining and/or improving the level of service. In this report, consolidation is defined as the reduction in the number of locally managed PSAPs and PSDPs that provide emergency communications services