scholarly journals Optimization of Aircraft Climb Trajectory considering Environmental Impact under RTA Constraints

2020 ◽  
Vol 2020 ◽  
pp. 1-17
Author(s):  
Junqiang Wan ◽  
Honghai Zhang ◽  
Fangzi Liu ◽  
Wenying Lv ◽  
Yifei Zhao
Keyword(s):  
Fuel Consumption ◽  
Greenhouse Effect ◽  
Time Window ◽  
Optimization Method ◽  
Warming Trend ◽  
Weighting Factor ◽  
Pollutant Emission ◽  
Sustainable Operation ◽  
Aircraft Performance ◽  
The Impact

In order to realize the concept of air traffic sustainable operation, taking the aircraft climbing stage as an example, firstly, we establish the vertical trajectory model of aircraft climbing, analyze the change rule of aircraft performance parameters under different indicated airspeed, and establish the RTA and RHA constraint models according to the waypoint constraints. Then, considering the fuel economy and the greenhouse effect of pollutant emission, we establish a multiobjective model of aircraft flight parameter optimization, and, based on the multiobjective genetic algorithm, we establish an optimization model. Finally, we use B737-800 aircraft to carry out simulation experiments and find that, with the change of speed, fuel consumption and warming trend are different, and “objective weight, aircraft mass, flight distance, RTA time window, and wind” have different effects on the optimization results. The results show that this optimization method has a good compromise between fuel consumption and greenhouse effect by changing the weighting factor. By optimizing the flight parameters of the aircraft, it can effectively reduce the impact on the environment and provide theoretical support for the green flight of the aircraft.

scholarly journals Study on the Optimization Method of Point Merge Procedure Based on Benefit in the Terminal Area

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Yong Tian ◽  
Dawei Xing ◽  
Lili Wan ◽  
Bojia Ye
Keyword(s):  
Fuel Consumption ◽  
Rapid Development ◽  
Flow Distribution ◽  
Optimization Method ◽  
Flight Time ◽  
Pollutant Emission ◽  
Flight Operations ◽  
Obstacle Clearance ◽  
Noise Impact ◽  
Terminal Area

With the rapid development of the air transport industry, the problem of airspace congestion and flight delay in the terminal area (TMA) becomes more and more serious. In order to improve the efficiency of flight operations in TMA, point merge procedure had been devised. This paper takes the approach routes in TMA as the research object, taking into account such conditions as obstacle clearance, flight interval, and procedure area. Based on the flight time, fuel consumption, pollutant emission, and noise impact, an optimization model of point merge procedure is constructed. Genetic algorithm is used to optimize the structure of procedure. The Shanghai Hongqiao International Airport is selected for simulation verification, and the actual flow distribution of the airport is analyzed as an example. The results show that the average flight time was reduced by 0.26 min, the average fuel consumption was reduced by 1,240.64 kg, the average NOx emissions were reduced by 1.09 kg, and the noise impact range was contracted by 55 km2 after optimization. The point merge procedure optimization method can be expected to reduce the flight time, fuel consumption, and environmental impact of flights in TMA, so as to optimize the aircraft approach trajectory.

scholarly journals 4D Trajectory Planning of Aircraft Taxiing considering Time and Fuel

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Ningning Zhao ◽  
Nan Li ◽  
Yu Sun ◽  
Zheng Gao
Keyword(s):  
Path Planning ◽  
Velocity Profile ◽  
Fuel Consumption ◽  
Shortest Path ◽  
Traffic Control ◽  
Optimization Method ◽  
Pollutant Emissions ◽  
Optimal Velocity ◽  
Reduce Emissions ◽  
The Impact

Most of the traditional taxi path planning studies assume that the aircraft is in uniform speed, and the model is optimized based on the shortest taxi time. Although it is easy to solve, it does not consider the change of the speed profile when the aircraft turns, and the optimal taxiing time of the aircraft does not necessarily bring the optimal taxiing fuel consumption. In this paper, the aircraft’s taxi distance and the number of turns in the taxi are considered. The aircraft path planning model with the shortest total distance of the airport surface is established. The improved A ∗ algorithm is used to obtain the shortest path P. Based on this, the shortest path P is established. Considering the multitarget velocity profile model of time and fuel consumption, a heuristic search is used to generate an accurate velocity profile for each path to obtain a 4D trajectory of the aircraft and then quantitative analysis of the impact of aircraft pollutant emissions on the airport environment based on 4D trajectory taxi time. The experimental results show that, compared with the traditional optimization method without considering the turning times, the total taxiing distance and turning times of the aircraft are greatly reduced. By balancing the taxiing time and fuel consumption, a set of Pareto-optimal velocity profiles is generated for the aircraft taxiing path; at the same time, it will help the airport save energy and reduce emissions and improve the quality of the airport environment. It has a high practical application value and is expected to be applied in the real-time air traffic control decision of aircraft surface in the future.

scholarly journals The influence of driving pattern on pollutant emission and fuel consumption of hybrid electric vehicle

2019 ◽  
Vol 177 (2) ◽  
pp. 145-150
Author(s):  
Jakub LASOCKI ◽  
Maciej GIS
Keyword(s):  
Fuel Consumption ◽  
The Other ◽  
Pollutant Emission ◽  
Valuable Insight ◽  
Vehicle Speed ◽  
Actual Performance ◽  
Driving Cycles ◽  
Driving Pattern ◽  
Hybrid Electric ◽  
The Impact

Hybrid electric vehicles (HEVs) have an increasing presence in passenger transport segment. They have been designed to minimize energy consumption and pollutant emission. However, the actual performance of HEVs depends on the dynamic conditions in which they are used, and vehicle speed is one of the key factors. A lot of excess emission and fuel consumption can be attributed to rapid changes of vehicle speed, i.e. accelerations and decelerations. On the other hand, dynamic driving favours energy recovery during braking. This study examines the relationship between HEVs speed, pollutant emission and fuel consumption. The considerations were based on the results of testing vehicles in WLTC and NEDC driving cycles, performed on a chassis dynamometer. The test objects were two light-duty passenger vehicles, one with series-parallel, gasoline-electric hybrid system and the other, used as a reference, with conventional sparkignition engine. Both vehicles had similar technical parameters and combustion engines supplied with gasoline. The driving cycles were divided into several parts according to the speed range. For each part, pollutant emission and fuel consumption were determined and appropriate values of selected parameters of driving pattern were calculated. Combining the results of empirical research and calculated parameters allowed to obtain characteristics. Their analysis provided valuable insight into the impact of driving pattern on actual emission and fuel consumption of HEV.

scholarly journals Dynamic Optimization Method for Broadband ADCP Waveform with Environment Constraints

Sensors ◽  
2021 ◽  
Vol 21 (11) ◽  
pp. 3768
Author(s):  
Yongshou Yang ◽  
Shiliang Fang
Keyword(s):  
Distance Estimation ◽  
Acoustic Doppler Current Profiler ◽  
Optimization Method ◽  
Measurement Range ◽  
Velocity Estimation ◽  
Estimation Accuracy ◽  
Dynamic Configuration ◽  
Optimal Velocity ◽  
Flood Warning ◽  
The Impact

Broadband acoustic Doppler current profiler (ADCP) is widely used in agricultural water resource explorations, such as river discharge monitoring and flood warning. Improving the velocity estimation accuracy of broadband ADCP by adjusting the waveform parameters of a phase-encoded signal will reduce the velocity measurement range and water stratification accuracy, while the promotion of stratification accuracy will degrade the velocity estimation accuracy. In order to minimize the impact of these two problems on the measurement results, the ADCP waveform optimization problem that satisfies the environment constraints while keeping high velocity estimation accuracy or stratification accuracy is studied. Firstly, the relationship between velocity or distance estimation accuracy and signal waveform parameters is studied by using an ambiguity function. Secondly, the constraints of current velocity range, velocity distribution and other environmental characteristics on the waveform parameters are studied. For two common measurement applications, two dynamic configuration methods of waveform parameters with environmental adaptability and optimal velocity estimation accuracy or stratification accuracy are proposed based on the nonlinear programming principle. Experimental results show that compared with the existing methods, the velocity estimation accuracy of the proposed method is improved by more than 50%, and the stratification accuracy is improved by more than 22%.

OPTIMAL REINSURANCE FROM THE VIEWPOINTS OF BOTH AN INSURER AND A REINSURER UNDER THE CVAR RISK MEASURE AND VAJDA CONDITION

2021 ◽  
pp. 1-29
Author(s):  
Yanhong Chen
Keyword(s):  
Loss Function ◽  
Value At Risk ◽  
Numerical Study ◽  
Risk Measure ◽  
Convex Combination ◽  
Weighting Factor ◽  
Loss Functions ◽  
Conditional Value At Risk ◽  
Optimal Reinsurance ◽  
The Impact

ABSTRACT In this paper, we study the optimal reinsurance contracts that minimize the convex combination of the Conditional Value-at-Risk (CVaR) of the insurer’s loss and the reinsurer’s loss over the class of ceded loss functions such that the retained loss function is increasing and the ceded loss function satisfies Vajda condition. Among a general class of reinsurance premium principles that satisfy the properties of risk loading and convex order preserving, the optimal solutions are obtained. Our results show that the optimal ceded loss functions are in the form of five interconnected segments for general reinsurance premium principles, and they can be further simplified to four interconnected segments if more properties are added to reinsurance premium principles. Finally, we derive optimal parameters for the expected value premium principle and give a numerical study to analyze the impact of the weighting factor on the optimal reinsurance.

scholarly journals Management of Chipping Operations in Polish Forests

2020 ◽  
Vol 3 (1) ◽  
pp. 56
Author(s):  
Arkadiusz Gendek ◽  
Monika Aniszewska ◽  
Witold Zychowicz ◽  
Tadeusz Moskalik ◽  
Jan Malaťák ◽  
...  
Keyword(s):  
Fuel Consumption ◽  
Travel Distance ◽  
Operating Efficiency ◽  
Site Location ◽  
Work Shift ◽  
Work Site ◽  
The Mean ◽  
The Impact ◽  
Machine Base

The aim of the research was to verify the impact of selected parameters on the efficiency and organization of chipper operations. The paper analyzes chipping operations in Polish forests with a focus on work site location, overnight chipper location, chipper workload per site, fuel consumption, and work shift duration, as all of these factors may affect operating efficiency. The mean chipper travel distance between sites during a shift ranged from 4.74 km to 9.5 km (chippers moved on average every other day). The mean work shift duration was 12.4 h. At the end of a shift, the chippers traveled on average from 4.2 km to 6.3 km to an overnight location. At the beginning of a workday, the chippers were dispatched to sites at a distance of 2.5 km to 4.0 km. The average fuel consumption of the forwarder-mounted chippers was 16 L/h and that of the truck-mounted chipper was 7.7 L/h. It was found that the following actions have a decisive influence on the effectiveness of the operation of the chippers: determination of the size of individual tasks and the deployment of successive forest areas, indication of the proper location of the machine base, and the method of accessing the forest area.

scholarly journals Impact of COVID-19 pandemic on HIV viremia: a single-center cohort study in northern Italy

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Ilaria Izzo ◽  
Canio Carriero ◽  
Giulia Gardini ◽  
Benedetta Fumarola ◽  
Erika Chiari ◽  
...  
Keyword(s):  
Time Window ◽  
Time Windows ◽  
Continuum Of Care ◽  
Northern Italy ◽  
Hiv Diagnosis ◽  
Hiv Patients ◽  
Before And After ◽  
Missed Visits ◽  
Hiv Continuum Of Care ◽  
The Impact

Abstract Background Brescia Province, northern Italy, was one of the worst epicenters of the COVID-19 pandemic. The division of infectious diseases of ASST (Azienda Socio Sanitaria Territoriale) Spedali Civili Hospital of Brescia had to face a great number of inpatients with severe COVID-19 infection and to ensure the continuum of care for almost 4000 outpatients with HIV infection actively followed by us. In a recent manuscript we described the impact of the pandemic on continuum of care in our HIV cohort expressed as number of missed visits, number of new HIV diagnosis, drop in ART (antiretroviral therapy) dispensation and number of hospitalized HIV patients due to SARS-CoV-2 infection. In this short communication, we completed the previous article with data of HIV plasmatic viremia of the same cohort before and during pandemic. Methods We considered all HIV-patients in stable ART for at least 6 months and with at least 1 available HIV viremia in the time window March 01–November 30, 2019, and another group of HIV patients with the same two requisites but in different time windows of the COVID-19 period (March 01–May 31, 2020, and June 01–November 30, 2020). For patients with positive viremia (PV) during COVID-19 period, we reported also the values of viral load (VL) just before and after PV. Results: the percentage of patients with PV during COVID-19 period was lower than the previous year (2.8% vs 7%). Only 1% of our outpatients surely suffered from pandemic in term of loss of previous viral suppression. Conclusions Our efforts to limit the impact of pandemic on our HIV outpatients were effective to ensure HIV continuum of care.

scholarly journals Investment Incentives in Competitive Electricity Markets

2018 ◽  
Vol 8 (10) ◽  
pp. 1978 ◽  
Author(s):  
Jaber Valinejad ◽  
Taghi Barforoshi ◽  
Mousa Marzband ◽  
Edris Pouresmaeil ◽  
Radu Godina ◽  
...  
Keyword(s):  
Electricity Markets ◽  
Electricity Market ◽  
Planning Horizon ◽  
Optimization Method ◽  
Design Criterion ◽  
Mixed Integer ◽  
Investment Incentives ◽  
Mixed Integer Linear Program ◽  
Interconnected Power System ◽  
The Impact

This paper presents the analysis of a novel framework of study and the impact of different market design criterion for the generation expansion planning (GEP) in competitive electricity market incentives, under variable uncertainties in a single year horizon. As investment incentives conventionally consist of firm contracts and capacity payments, in this study, the electricity generation investment problem is considered from a strategic generation company (GENCO) ′ s perspective, modelled as a bi-level optimization method. The first-level includes decision steps related to investment incentives to maximize the total profit in the planning horizon. The second-level includes optimization steps focusing on maximizing social welfare when the electricity market is regulated for the current horizon. In addition, variable uncertainties, on offering and investment, are modelled using set of different scenarios. The bi-level optimization problem is then converted to a single-level problem and then represented as a mixed integer linear program (MILP) after linearization. The efficiency of the proposed framework is assessed on the MAZANDARAN regional electric company (MREC) transmission network, integral to IRAN interconnected power system for both elastic and inelastic demands. Simulations show the significance of optimizing the firm contract and the capacity payment that encourages the generation investment for peak technology and improves long-term stability of electricity markets.

Sex and Conception Probability

2021 ◽  
Author(s):  
Justin C. Konje ◽  
Oladipo A. Ladipo
Keyword(s):  
Menstrual Cycle ◽  
Sexual Intercourse ◽  
Time Window ◽  
Continuous Process ◽  
Female Genital Tract ◽  
Human Reproduction ◽  
Current Evidence ◽  
Fertile Window ◽  
Time Period ◽  
The Impact

Central to the survival of any species is the ability to procreate. In most cases, procreation is sexual, involving a process that ensures appropriate and timed contact between the male and female gametes. Successful human reproduction is premised on sexual intercourse occurring at a time when there is a receptive endometrium as well as an ovum ready for fertilization by spermatozoa. This time window of the menstrual cycle known as the fertile or fecund window is poorly defined and highly variable from one individual to another. Furthermore, while spermatogenesis is a continuous process, the impact of too frequent intercourse (defined as that occurring more than every 2 to 3 days) on fertilization has often been thought to be associated with a decreased fertilization potential of spermatozoa. Current evidence challenges previously held views on the fertile window and how it is determined, the timing of intercourse and how it is related to conception and miscarriages, the length of the luteal phase, and the precise time period during which the chances of fertilization are highest in any given menstrual cycle. The ability of spermatozoa to survive in the female genital tract for 5 days means fertilization can occur up to 5 days from sexual intercourse. During each menstrual cycle, there is a window of 5 to 6 days for fertilization to occur, and this period is defined not by the length of the cycle but by the timing of ovulation, with the chances of fertilization highest with intercourse occurring 1 to 2 days before ovulation.

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