基于4G通信的民机试飞遥测监控技术架构

民机适航审定试飞时需要传输海量的测试数据,由于试验科目的苛刻要求,试飞任务需在多地同时开展。针对这种需求,提出一种基于4G通信的民机试飞监控技术架构,构建多地试飞一体化测试网络,并通过了飞行试验数据传输测试,该技术架构可满足试验机试飞数据高速传输需求,满足试验数据多地传输需求。该技术的应用增强了安全监控能力,提高试飞效率。     

基于DPHM的民用飞机地面支持系统设计

国内故障诊断、预测与健康管理领域尚未形成完整的健康管理系统,地面支持系统的架构研究处于起步阶段。通过借鉴国际先进的民机健康管理的技术、规范和成功经验,深入研究了民机运营支持和产品技术支援的健康管理业务需求和应用需求,从数据模型、平台架构、业务架构三个方面提出了民用飞机基于DPHM的地面支持系统架构设计方案。依据架构设计方案,开发了原理样机,并进行了实验验证。实验验证显示,原理样机能够正确解码原始数据,演示功能符合预期,模块间接口顺畅,从而表明了地面支持系统架构设计方案的可行性。     

Unattended acoustic events classification at the vicinity of airports

This paper describes a method for the automatic identification of acoustic events using a weighted average of sound pressure and sound intensity measured at the vicinity of airports. The classification is based on the combination of different parameters using a technique conceptually similar to the sensor fusion: the indications of different classifiers are merged using the classification uncertainty as a figure of merit. The method uses the results of a training phase for the observation of statistical distributions of sound pressure and sound intensity related parameters. The different parameters’ weights are computed analyzing the overlap of probability distributions of takeoffs and landings, so that more relevance is given to the quantities presenting a low risk of misclassification. The proposed method does not require any arbitrary assumption about the parameter effectiveness, given that the indications of multiple (potentially infinite) classifiers can be merged together with weights that minimize the chance of misclassification. The method has been validated with measurements performed at the Milan Malpensa airport (Italy). Results outlined that the proposed classification criterion correctly identifies approximately 99% of events.     

How can soundscapes affect the preferred walking pace?

In this paper we describe an experiment whose goal is to investigate the role of the footstep sounds and soundscapes to affect the pace of a person walking in place (mimicking the act of walking without leaving the current position). Subjects were exposed to different simulated footstep sounds and soundscapes, generated in realtime while walking in place. The results show that, indeed, participants adapted their walking pace to the presented sounds, and not only footstep sounds but also soundscapes affect the walking pace. We could observe as well that perceived ease of walking correlates with the perceived naturalness of ambient sounds.     

Aircraft control for flight in an uncertain environment: Takeoff in windshear

The design of the control of an aircraft encountering windshear after takeoff is treated as a problem of stabilizing the climb rate about a desired value of the climb rate. The resulting controller is a feedback one utilizing only climb rate information. Its robustness vis-a-vis windshear structure and intensity is illustrated via simulations employing four different windshear models.Notations ARL aircraft reference line - D drag force, lb - g gravitational force per unit mass=const, ft sec^–2 - h vertical coordinate of aircraft center of mass (altitude), ft - L lift force, lb - m aircraft mass=const, lb ft^–1 sec² - O mass center of aircraft - S reference surface, ft² - t time, sec - T thrust force, lb - V aircraft speed relative to wind-based reference frame, ft sec^–1 - V _e aircraft speed relative to ground, ft sec^–1 - W _x horizontal component of wind velocity, ft sec^–1 - W _h vertical component of wind velocity, ft sec^–1 - x horizontal coordinate of aircraft center of mass, ft - relative angle of attack, rad - relative path inclination, rad - _e path inclination, rad - thrust inclination, rad - air density=const, lb ft² sec² Dot denotes time derivative.     

A single step ice accretion model using Level-Set method

A new approach using the Level-Set framework is developed in the NSMB (Navier–Stokes-multi-block) compressible solver for modeling the ice/air interface evolution through time during in-flight icing. Droplet distribution and impingement efficiency are computed by an Eulerian approach and the accreted ice is calculated by a PDE model. An icing velocity field is introduced and the Level-Set equations are solved on body-fitted multi-block structured grids. The whole process is parallelized with the MPI library for efficient calculations. Single step icing is simulated on NACA23012 and NACA0012 airfoils and on the ONERA-M6 and the GLC-305 swept wings. In all the studied cases, the results are in good agreement with existing and available data validating the feasibility of the approach.     

Improvements to a large neighborhood search heuristic for an integrated aircraft and passenger recovery problem

Because most commercial passenger airlines operate on a hub-and-spoke network, small disturbances can cause major disruptions in their planned schedules and have a significant impact on their operational costs and performance. When a disturbance occurs, the airline often applies a recovery policy in order to quickly resume normal operations. We present in this paper a large neighborhood search heuristic to solve an integrated aircraft and passenger recovery problem. The problem consists of creating new aircraft routes and passenger itineraries to produce a feasible schedule during the recovery period. The method is based on an existing heuristic, developed in the context of the 2009 ROADEF Challenge, which alternates between three phases: construction, repair and improvement. We introduce a number of refinements in each phase so as to perform a more thorough search of the solution space. The resulting heuristic performs very well on the instances introduced for the challenge, obtaining the best known solution for 17 out of 22 instances within five minutes of computing time and 21 out of 22 instances within 10 minutes of computing time.     

The Aircraft Maintenance Base Location Problem

Aviation authorities such as the Federal Aviation Administration (FAA) provide stringent guidelines for aircraft maintenance, with violations leading to significant penalties for airlines. Moreover, poorly maintained aircraft can lead to mass cancellation of flights, causing tremendous inconvenience to passengers and resulting in a significant erosion in brand image for the airline in question. Aircraft maintenance operations of a complex and extended nature can only be performed at designated maintenance bases. Aircraft maintenance planning literature has focused on developing good tail-number routing plans, while assuming that the locations of the maintenance bases themselves are fixed. This paper considers an inverse optimization problem, viz., locating a minimal number of maintenance bases on an Euler tour, while ensuring that all required aircraft maintenance activities can be performed with a stipulated periodicity. The Aircraft Maintenance Base Location Problem (AMBLP) is shown to be NP-complete and a new lower bound is developed for the problem. The performance of four simple “quick and dirty” heuristics for obtaining feasible solutions to AMBLP is analyzed.     

Characteristics of road traffic noise in Hanoi and Ho Chi Minh City, Vietnam

Noise pollution due to road traffic is a major global concern because of its negative impact on the quality of life in communities everywhere. In Vietnam, traffic noise has become an increasingly noticeable and serious problem in large cities like Hanoi and Ho Chi Minh City. To gain more insight into the characteristics of this noise, intensive noise measurements were conducted in Hanoi and Ho Chi Minh City in September 2005 and September 2007, respectively. A comprehensive dataset of noise was obtained that included 24-h noise measurements as well as short-term noise recordings. The volume of traffic was also quantified by reproducing video camera recordings. Noise datasets from both cities were then compared with a dataset of Japanese traffic noise obtained in Kumamoto. The results showed that the traffic noise in Hanoi and Ho Chi Minh City was characterized by relatively high noise exposure levels due to the large number of motorbikes and frequent horn sounds. The sound of horns contributed a definite impact of 0-4 dB on noise exposure in Hanoi and Ho Chi Minh City, where noise levels decreased with the absence of horn sounds. Our results also showed differences in the characteristic traffic noise of Vietnam and Japan.     

Scraping sounds and disgusting noises

Thirty-four horrible sounds have been examined in an Internet-based psychoacoustic experiment. This paper presents the results for the scraping and disgusting noises used. It is not understood why some humans find certain scraping noises, such as the sound of fingernails being scraped down a blackboard, so terrible. In this experiment, the variations in ratings with age, gender and location are examined. The results for one of the scraping sounds is consistent with the hypothesis suggested by others, that the response comes from a vestigial reflex related to the warning cries of monkeys. But this was not true for the actual recording of the fingernails scraping down a blackboard. An alternative hypothesis that the response is related to an audio-haptic interaction was tested and results indicated that this idea warrants further investigation. Other possible causes of the response, drawing on work concerning dissonance, are tentatively suggested. The disgusting sounds examined included the worst sound found in the experiment, the sound of someone vomiting. However, none of the disgusting sounds tested promoted responses consistent with a ‘disgust reaction’ based purely on survival instincts. Cultural factors might be important in our response to the disgusting sounds, with the influence of manners and etiquette being suggested as a possible factor.