Drone-based electromagnetic survey system for geophysical applications

Geophysical electromagnetic (EM) methods are used in geological mapping, mineral exploration, groundwater studies and geotechnical investigations. Airborne EM methods have the benefit of avoiding terrain obstacles such as lakes, rivers, swamps, and ravines. Compared to manned aircrafts, drones or unmanned aerial vehicles (UAVs) have benefits of their own. Drone-based surveys are versatile, fast to deploy, economical and ecologically more friendly. Presently, magnetic surveying is the only geophysical method that is routinely conducted with drones. The modest maximum payload limit of drones imposes severe restrictions on the applicability of other methods including EM and radiometric methods, for example. Finnish company, Radai Ltd has been developing Louhi, a novel drone-based frequency-domain EM survey system, in an EU funded Horizon 2020 project NEXT – New Exploration Technologies. The EM system has two operation options – the first uses a large loop on the ground as an EM source and the other uses a small portable EM transmitter loop. Both systems utilize a stand-alone and light-weight three-component EM receiver that can be towed by a drone. This article presents the theoretical background of the EM methods, the solution developed by Radai Ltd, the current version of the EM device, and results from field and flight tests that demonstrate the applicability of the drone-based EM system under development.

A trade-off methodology for micro-launchers

The trend of cost-effective access to space and satellite technologies’ evolution is increasing the small satellite market. However, small payloads usually ride as piggyback, being a secondary passenger of a space vector, with very low flexibility in target orbit and launch schedule. The micro-launchers are designed to answer the needs of the small satellite missions, with a payload capacity up to 350 kg to Low Earth Orbit, aiming to low turn-over time and competitive prices. This paper explains the work performed by Politecnico di Torino in support of the ESA–ESTEC activities on micro-launchers. The aim is to provide preliminary guidelines for choosing and evaluating new innovative micro-launcher flight vehicle engineering processes. A trade-off methodology is proposed and defined based on the Analytically Hierarchical Process (AHP). This methodology considers, among other features, the flight profile, maximum payload, and physical characteristics. To support the trade-off analysis, a software tool is built for the automatic generation of the aerodynamics and propulsion parameters needed for the completion of the preliminary designs, enabling the performance estimation. The launcher’s performance models, with an analysis of the take-off sites and target orbits, are also produced. This allows the definition of performance maps where the maximum payload is graphed as a function of the orbit altitude and inclination. A set of innovative micro-launchers exploiting different technologies is also assessed as a case study.

Multimedia Communication Security in 5G/6G Coverless Steganography Based on Image Text Semantic Association

Recently, researchers have shown that coverless steganography is relatively safe. On this basis, to improve the payload of the coverless steganography, a novel semiconstruction coverless steganography algorithm is introduced in the paper. Firstly, web crawler technology is applied to crawl a wide range of small icons and hot news images from the Internet. These icons can be used as the training subset, and the hot news can be designed according to construction rules. Secondly, the Alex-Net network is introduced for training in the algorithm, and the adversarial samples are added to the training set. Thirdly, using the preset template, certain small icons and a hot news image are spliced into a secret carrier image according to the construction principle. The hot news image is in the top half of the carrier, and those small icons are in the bottom half. The image on the upper part of the carrier and the icons of the lower part can be connected by image and text semantics, and the semantic matching can be realized between image semantics and explanatory. The experimental results and analysis show that the proposed algorithm can resist steganalysis tools effectively and has good robustness against various image attacks. Meanwhile, the secret information payload has been greatly improved, the maximum payload can reach 180 bits of a single 512 × 512 image. This promising algorithm can be applied to build covert communications.

Monte Carlo Simulation of Supply and Demand for Payload Limited Routes

ABSTRACT Large commercial aircraft by design are typically not capable of transporting maximum fuel capacity and maximum payload simultaneously. Beyond the maximum payload range, fuel requirements reduce payload capability. Varying environmental conditions further impact payload capability noticeably. An airline's commercial department requires prior knowledge of any payload restrictions, to restrict booking levels accordingly. Current forecasting approaches use monthly average performance, at, typically, the 85% probability level, to determine such payload capability. Such an approach can be overly restrictive in an industry where yields are marginal, resulting in sellable seats remaining empty. Monte Carlo simulation principles were applied to model the variance in environmental conditions, as well as in the expected payload demand. The resulting forecasting model allows the risk of demand exceeding supply to be assessed continually. Payload restrictions can then be imposed accordingly, to reduce the risk of demand exceeding supply to a required risk level. Additional keywords: Fuel, payload, forecasting, performance, environment.

An Event-Driven Serverless ETL Pipeline on AWS

This work presents an event-driven Extract, Transform, and Load (ETL) pipeline serverless architecture and provides an evaluation of its performance over a range of dataflow tasks of varying frequency, velocity, and payload size. We design an experiment while using generated tabular data throughout varying data volumes, event frequencies, and processing power in order to measure: (i) the consistency of pipeline executions; (ii) reliability on data delivery; (iii) maximum payload size per pipeline; and, (iv) economic scalability (cost of chargeable tasks). We run 92 parameterised experiments on a simple AWS architecture, thus avoiding any AWS-enhanced platform features, in order to allow for unbiased assessment of our model’s performance. Our results indicate that our reference architecture can achieve time-consistent data processing of event payloads of more than 100 MB, with a throughput of 750 KB/s across four event frequencies. It is also observed that, although the utilisation of an SQS queue for data transfer enables easy concurrency control and data slicing, it becomes a bottleneck on large sized event payloads. Finally, we develop and discuss a candidate pricing model for our reference architecture usage.

KERETA API SCS: ANGKUTAN GULA DI CIREBON

Gula merupakan salah satu komoditas perdagangan penting pada masa kolonial Belanda. Hasil yang berlimpah tidak diimbangi dengan ketersediaan angkutan barang. Minimnya volume angkut dan lamanya waktu tempuh merupakan permasalahan yang dihadapi pengusaha gula. Pengembangan moda transportasi kereta api menjadi jawaban atas permasalahan tersebut. Daya angkut besar dengan waktu tempuh yang lebih cepat menjadi kelebihannya. Tujuan penelitian ini adalah menguraikan peranan kereta api dalam pengangkutan gula ke pelabuhan di Karesidenan Cirebon. Metode yang dipergunakan, deskriptif analisis. Data dikumpulkan melalui kegiatan studi pustaka dan pengamatan lapangan. Hasil penelitian menunjukkan, jalur kereta api di Karesidenan Cirebon merupakan bagian dari jalur Semarang – Cirebon yang dibangun oleh NV. SCS. Tinggalan perkeretaapian di jalur tersebut menunjukkan terdapat persimpangan ke pabrik gula dari stasiun terdekat. Kesimpulan, pembangunan perkeretaapian di Cirebon pada awalnya ditujukan sebagai angkutan komoditas gula. Sugar was one of the important trade commodities during the Dutch occupation. The abundant production of sugar disproportionated to the availability of freight transportation. Its consequences, the sugar company was hampered by both the low volumes and and the slow journey time of transported goods. As a result, the development of modes of transport was the solution needed. It would provide the solution based on the maximum payload and highest average speeds. The purpose of this study is to describe the role of railways in transporting sugar industry to the port in the Cirebon Residency. The research method used in the study is descriptive analysis. Research data were derived from library study, and field observations. The results of the study have shown that the railway line in Cirebon Residency was actually a part of the Semarang - Cirebon railway line built by NV. SCS. The disused railroad indicate clearly that there was an intersection to the sugar company from the nearest train station. It concluded that the railway construction in Cirebon was initially intended as the sugar transportation.

Genuine Reversible Data Hiding Technique for H.264 Bitstream Using Multi-Dimensional Histogram Shifting Technology on QDCT Coefficients

Video has become the most important medium for communication among people. Video has become the most important medium for communication among people. Therefore, reversible data hiding technologies for video have been developed so that information can be hidden in the video without damaging the original video in order to be used in the copyright protection and distribution field of video. This paper proposes a practical and genuine reversible data hiding method by using a multi-dimensional histogram shifting scheme on QDCT coefficients in the H.264/AVC bitstream. The proposed method defines the vacant histogram bins as a set of n-dimensional vectors and finds the optimal vector space, which gives the best performance, in a 4 × 4 QDCT block. In addition, the secret message is mapped to the optimal vector space, which is equivalent to embedding the information into the QDCT block. The simulation results show that the data hiding efficiency is the highest among the compared five existing methods. In addition, the image distortion and maximum payload capacity are measured quite high.

The Aircraft Choice Based on the Aircraft Take-Off Runway Length Requirement

The choice of fleet by a given airline must consider different elements associated with both the aircraft and the airports to be operated, making it necessary a method to assist the aircraft choice process. This study assesses the take-off runway distance requirement of different aircraft models and compares the requirement to the take-off runway distance available at a group of airports. Using the Herfindahl-Hirschman index (HHI), the methodology consider the analysis of take-off runway length available on 80 Brazilian airports and compared it to the take-off distance required for 108 combinations of aircraft model, engine model and flight range, considering the take-off performance of the aircraft models with maximum payload weight. In total, 536 routes of four Brazilian airlines has been adopted to simulate the most profitable operating scenario. The result presents the take-off performance of different aircraft models and allows a performance comparison between them. In addition, this research investigates which is the most common flight range in Brazil, and what influence it exerts in the aircraft take-off performance, and contributes to a better match between the aircraft used and the airport operated in fleet optimization.

Design and characterization of a hybrid soft gripper with active palm pose control

The design and characterization of a soft gripper with an active palm to control grasp postures is presented herein. The gripper structure is a hybrid of soft and stiff components to facilitate integration with traditional arm manipulators. Three fingers and a palm constitute the gripper, all of which are vacuum actuated. Internal wedges are used to tailor the deformation of a soft outer reinforced skin as vacuum collapses the composite structure. A computational finite-element model is proposed to predict finger kinematics. Thanks to its active palm, the gripper is capable of grasping a wide range of part geometries and compliances while achieving a maximum payload of 30 N. The gripper natural softness enables robust open-loop grasping even when components are not properly aligned. Furthermore, the grasp pose of objects with various aspect ratios and compliances can be robustly maintained during manipulation at linear accelerations of up to 15 m/s2 and angular accelerations of up to 5.23 rad/s2.

Effect of hitch distance on haulage performance for 2WD tractors: A theoretical analysis

Aim of study: A computer program was developed in Visual Basic 10 environment for predicting the haulage performance of 2WD tractors using various empirical and theoretical equations.Methodology: Three types of inputs related to tractor, trailer and operating parameters were used to calculate the performance parameters through empirical and theoretical equations. The performance parameters included mainly draft, slip, transport efficiency, transport productivity, fuel economy index, rear and front axle dynamic weight, etc. The program was used to evaluate the haulage performance by varying hitch distance (HD) at various operating conditions.Main results: On one hand lower HD was beneficial in increasing the maximum payload, transport productivity as well as the maximum slope; but at the same time, it reduced the rear axle dynamic load, fuel economy index and actual engine power requirement.Research highlights: There was a markable effect of HD over tractor performance which can play a role to optimize traction and stability.