Anomaly detection of aircraft engine in FDR (flight data recorder) data

This paper deals with detection of anomalous behaviour of aircraft engines in FDR (flight data recorder) data to improve airline maintenance operations. To this end, each FDR data that records different flight patterns is first sampled at a fixed time interval starting at the take-off phase, in order to map each FDR data into comparable data space. Next, the parameters related to the aircraft engine are only selected from the sampled FDR data. In this analysis, the feature points are chosen as the mean value of each parameter within the sampling interval. For each FDR data, the feature vector is then formed by arranging all feature points. The proposed method compares the feature vectors of all FDR data and detects an FDR data in which the abnormal behaviour of the aircraft engine is recorded. The clustering algorithm called DBSCAN (density-based spatial clustering of applications with noise) is applied for this purpose. In this paper, the proposed method is tested using realistic FDR data provided by NASA's open database. The results indicate that the proposed method can be used to automatically identify an FDR data in which the abnormal behaviour of the aircraft engine is recorded from a large amount of FDR data. Accordingly, it can be utilized for a high-level diagnosis of engine failure in airline maintenance operations

Energy-optimal waypoint-following guidance considering autopilot dynamics

This paper addresses the problem of energy-optimal waypoint-following guidance for an Unmanned Aerial Vehicle with the consideration of a general autopilot dynamics model. The proposed guidance law is derived as a solution of a linear quadratic optimal control problem in conjunction with a linearized kinematics model. The algorithm developed integrates path planning and following into a single step and is able to be applied to a general waypoint-following mission. Theoretical analysis reveals that previously suggested optimal point-to-point guidance laws are special cases of the proposed approach. Nonlinear numerical simulations clearly demonstrate the effectiveness of the proposed formulations

A new multiple flights routing and scheduling algorithm in terminal manoeuvring area

We address multiple flights planning problems from its initial waypoint to its destination while satisfying the minimum separation requirement between each aircraft at all times in a Terminal Manoeuvring Area (TMA) to maintain or increase runway throughput. Due to operational constraints for safety, most of the current aircraft fly over or by waypoints, and along nominal routes in the airspace. Where the waypoints and routes in the airspace can be modelled as a weighted digraph, called airspace graph. We propose a problem that consists of determining a flight path (routing problem) and its speed profile (scheduling problem) in a given airspace graph in which a time-based weighting scheme of the airspace graph is proposed to reflect a speed-limitation-compliant schedule that satisfy the minimum separation requirement. For multiple flights cases, the flight paths and schedules are obtained by iteratively solving the problem for each flight by applying the First Come First Served (FCFS) algorithm to determine an arrival sequence. The main contributions of this paper are increasing a solution search space by solving two problems simultaneously, efficient computational time, and providing the separation-compliant flight path and speed profile within the speed limitation for each flight. We demonstrate the advantages of the proposed approach through a case study in which multiple flights arrive at a single airport, and we compare the results with Regulated Tactical Flight Model (RTFM) obtained from EUROCONTROL Demand Data Repository 2 (DDR2). Although, we consider only a single airport and make an assumption to simplify flight routes from holding stacks to a Final Approach Fix (FAF), the results show the potential usage of the proposed algorithm as a Decision Support Tool (DST) for Air Traffic Controllers (ATCOs) if the following considerations are taken into account: detailed routes-based flights after the holding stacks, multiple airports, departing aircraft, all possibe aircraft types, and uncertainties produced by external sources

A new command shaping guidance law using Lagrange multiplier

This article presents a new command shaping guidance law by change of Lagrange multiplier (LM), called CSGL-LM. The Schwarz inequality approach is used to solve the optimal guidance problems considering both terminal constraints on interception and impact angle control. LM is introduced to combine two terminal constraints into a single equation. The main idea of this paper is to use LM as a design parameter for shaping the guidance command as well as controlling the terminal constraints. The guidance command of CSGL-LM is given a unified functional form of the time-to-go, the state variables, and LM. Therefore, through an appropriate choice of LM, we can achieve various shapes of the guidance commands for the interception case, as well as the impact angle control case. As illustrative examples, this paper also shows that a class of previous guidance laws is just one of particular solutions of CSGL-LM. Numerical simulations are performed to validate the properties of CSGL-LM, compared with the conventional guidance law

Nonlinear acceleration controller for exo-atmospheric and endo-atmospheric interceptors with TVC

In this paper, we propose a nonlinear acceleration controller that can be used for both the endo- and exo-atmospheric interceptors with thrust vector control (TVC) without changing the control configuration. The acceleration perpendicular to the velocity vector is selected as the output to be controlled. Then apply the feedback linearization and the specific form of the desired error dynamics to create the resulting controller which is given by the well-known three loop control structure with parameter-varying control gains. According to changes in altitude operating conditions, the proposed controller can adaptively allocate the aerodynamic force and the thrust to produce the required normal acceleration. Also, we can have confidence in the reliability of the proposed controller because it is given by a similar form of the well-known three loop controller. Numerical simulations are performed to show the validity of the proposed method

Significance of EpCAM and TROP2 expression in non-small cell lung cancer

<p>Abstract</p> <p>Background</p> <p>The tumor-associated calcium signal transducer (<it>TACSTD</it>) genes, originally designated epithelial cell adhesion molecule (EpCAM) and TROP2, represent true oncogenes. Little is known about EpCAM and TROP2 gene expression in non-small cell lung carcinoma (NSCLC). This study evaluated EpCAM and TROP2 protein expression and clinicopathologic significance in cases of NSCLC.</p> <p>Methods</p> <p>Tissue microarray blocks acquired from 164 cases of NSCLC, including 100 cases of adenocarcinoma (AdC) and 64 of squamous cell carcinoma (SCC), were examined by immunohistochemical staining for EpCAM, and TROP2. The results were correlated with clinicopathologic data.</p> <p>Results</p> <p>EpCAM and TROP2 were significantly overexpressed in SCC than in AdC (<it>P </it>< 0.01). In AdC, EpCAM overexpression was closely related to sex, histologic grade, pathologic T stage, pathologic N stage, and TNM stage, and TROP2 overexpression was only related to histologic grade (<it>P </it>< 0.05, respectively). In SCC, correlations were evident between EpCAM overexpression and TNM stage (<it>P </it>= 0.01), and between TROP2 overexpression and pathologic T stage (<it>P </it>= 0.02). EpCAM overexpression showed no significance with overall survival in AdC and SCC patients. However, TROP2 overexpression in AdC had a positive influence on overall survival (<it>P </it>= 0.02) and disease-free survival (<it>P </it>= 0.03). In particular, AdC patients with stage II or III showed better overall survival (<it>P </it>= 0.05) and disease-free survival (<it>P </it>= 0.04).</p> <p>Conclusions</p> <p>While EpCAM and TROP2 show weak and non-complete membranous staining in normal bronchial epithelium and pneumocyte, their complete membranous expression in carcinoma suggests their role in carcinogenesis. EpCAM and TROP2 were more frequently overexpressed in SCC. EpCAM overexpression had no prognostic value in this study, but TROP2 overexpression showed better survival in AdC patients and might be a better prognostic marker in advanced stage AdC.</p

Electrical spin injection and accumulation in CoFe/MgO/Ge contacts at room temperature

We first report the all-electrical spin injection and detection in CoFe/MgO/moderately doped n-Ge contact at room temperature (RT), employing threeterminal Hanle measurements. A sizable spin signal of ~170 k{\Omega} {\mu}m^2 has been observed at RT, and the analysis using a single-step tunneling model gives a spin lifetime of ~120 ps and a spin diffusion length of ~683 nm in Ge. The observed spin signal shows asymmetric bias and temperature dependences which are strongly related to the asymmetry of the tunneling process.Comment: 28 pages, 5 figure

Effects of Platycodon grandiflorum methanolic extract on testosterone-induced benign prostatic hyperplasia in Wistar rats

Benign prostatic hyperplasia (BPH) is highly prevalent in the male population over the age of 60 years, manifesting as prostatic enlargement and distinctive changes in tissue histomorphology. In this study, we investigated whether a Platycodon grandiflorum methanolic extract (PGME) improved BPH in a testosterone propionate (TP)-induced model of BPH in rats. Castration was performed via the scrotal route under sodium pentobarbital anesthesia, and BPH was induced in the rats with a subcutaneous injection of TP (3 mg/kg) given every consecutive day for 4 weeks after castration. The control group of castrated rats received subcutaneous injections of corn oil. Experimentally, induced rat model of BPH, PGME led to significant reductions in prostate weight and dihydrotestosterone levels in the serum and prostate. Histologically, BPH was evident in the ventral lobe of the prostate, and PGME treatment significantly reduced the severity of the lesion. Therefore, PGME was effective in reducing TP-induced BPH in a rat model, and may be useful for the clinical treatment of patients with BPH.Keywords: Benign prostatic hyperplasia (BPH), dihydrotestosterone, testosterone, Platycodon grandifloru

Data analytics development of FDR (Flight Data Recorder) data for airline maintenance operations

In this article, we propose a data analytics development to detect unusual patterns of flights from a vast amounts of FDR (flight data recorder) data for supporting airline maintenance operations. A fundamental rationale behind this development is that if there are potential issues on mechanical parts of an aircraft during a flight, evidences for these issues are most likely included in the FDR data. Therefore, the data analysis of FDR data enables us to detect the potential issues in the aircraft before they occur. To this end, in a data pre-processing step, a data filtering, a data sampling, and a data transformation are sequentially performed. And then, in this analysis, all time series data in the FDR are classified into three types: a continuous signal, a discrete signal, and a warning signal. For each type of signal, a high-dimensional vector by arranging the time series data is chosen as features. In the feature section process, a correlation analysis, a correlation relaxation, and a dimension reduction are sequentially conducted. Finally, a type of k-nearest neighbor approach is applied to automatically identify the FDR data in which the unusual flight patterns are recorded from a large amount of FDR data. The proposed method is tested with using a realistic FDR data from the NASA's open database