The Role of the Federal Government in the Development of the US Air Transportation System

Reviewed are the roles of the various Federal agencies in the regulation, control, and development of the Air System, with major emphasis on the Department of Transportation (Office of the Secretary, Federal Aviation Administration, and National Transportation Safety Board) and the Civil Aeronautics Board

Basic Finance

A discussion of the basic measures of corporate financial strength, and the sources of the information is reported. Considered are: balance sheet, income statement, funds and cash flow, and financial ratios

Air service to small communities, directions for the future

The seminar on the problems of providing air service to low and medium density points is reported. National transport policies and programs are discussed along with the technology aspects. Recommendations for ATC, CAB, and FAA are included

An assessment of lighter than air technology

The workshop on LTA is summarized. The history and background are reviewed. The workshop reports for the following working groups are presented: policy, market analysis, economics, operations, and technology

Proceedings of the Interagency Workshop on Lighter than Air Vehicles

Papers presented at the workshop are reported. Topics discussed include: economic and market analysis, technical and design considerations, manufacturing and operations, design concepts, airship applications, and unmanned and tethered systems

Sliding mode vector control of PMSM drives with flexible couplings in motion control

A new control system for permanent magnet synchronous motor electric drives with a significant torsion vibration mode in the mechanical coupling is presented based entirely on sliding mode principles to achieve robustness against external load torques and parametric modelling uncertainties. The user is only required to provide the demanded position and specify the settling time, no controller tuning being necessary. The vector control condition of keeping the direct axis current component approximately zero is satisfied as well as controlling either the rotor or load position to follow the demanded position with prescribed closed loop dynamics. To avoid control chatter, a boundary layer is introduced by replacing the relay control switching transfer characteristic (signum function) by a high gain having the same control saturation limits. Any steady state errors with a constant demanded rotor angle due to the finite value of the aforementioned gain are eliminated by means of an outer integral control loop. The simulations predict that the desired robustness will be achieved

Aircraft requirements for low/medium density markets

A study was conducted to determine the demand for and the economic factors involved in air transportation in a low and medium density market. The subjects investigated are as follows: (1) industry and market structure, (2) aircraft analysis, (3) economic analysis, (4) field surveys, and (5) computer network analysis. Graphs are included to show the economic requirements and the aircraft performance characteristics

Hungarian International Development Cooperation: Context, Stakeholders and Performance

This paper explores the domestic and international context of Hungary's emerging international development policy. Specifically, it looks at three factors that may influence how this policy operates: membership in the European Union (EU) and potential ‘Europeanization’, Hungary's wider foreign policy strategy, and the influence of domestic stakeholders. In order to uncover how these factors affect the country's international development policy, semi-structured interviews were carried out with the main stakeholders. The main conclusions are: (1) While accession to the EU did play a crucial role in restarting Hungary's international development policy, the integration has had little effect since then; (2) international development policy seems to serve mainly Hungary's regional strategic foreign policy and economic interests, and not its global development goals; and (3) although all the domestic development stakeholders are rather weak, the Ministry of Foreign Affairs (MFA) still seems to play a dominating role. Convergence with European requirements and best practices is, therefore, clearly hindered by foreign policy interests and also by the weakness of non- governmental stakeholders

Vektorski upravljani elektromotorni pogoni s reluktantnim sinkronim motorima uz definiranu dinamiku zatvorenog kruga brzine vrtnje

A new speed control system for electric drives employing reluctance synchronous motors is presented. Design control system combines two control methods. Conventional vector control method is here completed with forced dynamics closed-loop control. Since the closed-loop system response is a first order lag whose pole location can be chosen by the user, the drive may be included as an actuator in a larger scale control scheme to which linear control system design methods can be applied. To improve robustness of the design control structure, the outer control loop based on model reference adaptive control is added. Simulation results presented show good correspondence with theoretical predictions and MRAC outer control loop improves overall drive performances.Prikazana je nova koncepcija sustava upravljanja brzinom vrtnje elektromotornog pogona s reluktantnim sinkronim motorima, temeljena na dvijema metodama upravljanja. Konvencionalna vektorska metoda nadograđena je elementom sustava koji predstavlja dinamiku zatvorenog kruga po brzini vrtnje. Budući da je dinamika zatvorenog sustava prikazana proporcionalnim članom prvog reda, čiji pol odabire korisnik, predložena koncepcija može biti šire primjenjiva. Da bi se poboljšala robusnost sustava, dodana je vanjska petlja upravljanja zasnovana na adaptivnom upravljanju s referentnim modelom. Simulacijski rezultati prikazani u radu potvrđuju valjanost predložene koncepcije

Dinamička simulacija mehaničkih opterećenja – pristup zasnovan na svojstvima industrijskih elektromotornih pogona

Dynamic emulation of mechanical loads presents a modern and interesting approach for testing and validating performance of electrical drives without a real mechanical load included in the test rig. The paper presents an approach to dynamic emulation of mechanical loads when the load torque and inertia mass of emulated load can be significantly greater than that of laboratory test rig. Closed-loop control of load torque and feedforward compensation of inertia and friction torques are used in a test rig. The approach is focused on the use with standard industrial converters. The described method can be used for design and validation of speed control algorithms in mechatronic applications. Experimental results with the emulation of linear loads are presented in end of the paper.Dinamička simulacija mehaničkih opterećenja predstavlja moderan i zanimljiv pristup testiranju i validaciji ponašanja elektromotornih pogona bez uključenog stvarnog mehaničkog opterećenja u eksperimentalni postav. U radu je predstavljen pristup s dinamičkom simulacijom mehaničkih opterećenja za slučaj kada moment tereta ili moment tromosti simuliranog tereta mogu biti daleko veći od onih dostupnih u eksperimentalnom postavu. U postavu se koristi upravljanje momentom tereta u zatvorenoj petlji uz unaprijednu petlju kompenzacije momenta tromosti i momenata trenja. Pristup je usmjeren na upotrebu standardnih industrijskih pretvarača. Opisana metoda može se koristiti za sintezu i validaciju algoritama za upravljanje po brzini u mehatroničkim primjenama. U radu su predstavljeni eksperimentalni rezultati za slučaj simulacije linearnih tereta