Comparison of Fuzzy Logic and Genetic Algorithm Based Admission Control Strategies for UMTS System

CDMA systems have so-called soft capacity, so the total number of possible sessions has not an exact value. The capacity of CDMA system depends on the interference level in the system. There are therefore RRM (Radio Resources Management) functions, which are responsible for supplying optimum coverage, ensuring efficient use of physical resources and providing the maximum planned capacity. This paper presents and compares several algorithms that are used for admission control purposes in UMTS system. Several versions of fuzzy logic based algorithms, load factor based algorithm and genetic based algorithm are mutually compared via simulations

Enhanced Receivers for Interference Cancellation in 3G Systems

Interference cancellation and multiuser detection in CDMA systems are still actual research topics. These techniques enable us to deal with interference and to increase system capacity. In this paper, a so-called Generalized RAKE receiver, an Uplink generalized multiuser detection and a Blind adaptive multiuser detection are described. These algorithms are compared with conventional receivers and their properties are verified via simulations. The results imply that some of these algorithms are able to overcome the performance of the conventional receivers

A Proposal for Ensuring the Quality of Aerospace Engineering Higher Education in Europe

The paper presents a possible roadmap for the definition of a European quality label for aerospace related higher education degrees. The proposal is the result of a two-years long Horizon 2020 project that has involved a great portion of the European stakeholders in aerospace: Universities, research centres, industries (both small and large) networks, associations and accreditation agencies. The core concept established is that it is possible to establish a sector-specific, content based, quality system, that can complement the existing national or European accreditation systems, providing added value to the internal and/or external quality assurance processes that are in place in most EU countries. The tools and processes proposed are sufficiently simple to be manageable by Universities in addition to their national accreditation processes or as stand-alone assessment. The main goal of the proposed process is the evaluation of the quality of the aerospace curricula in the European context, whereas the accreditation of the programme can be seen as an optional extension of the process, subject to further national regulations. The process is proposed in view of the awarding of a sector-specific, content based, quality label, to be issued by an appropriate legally recognized and qualified institution. A set of 8 field tests with volunteering universities throughout Europe has been performed. They experienced the method as very practical and to the point

Near-infrared observations of active asteroid (3200) Phaethon reveal no evidence for hydration

Asteroid (3200) Phaethon is an active near-Earth asteroid and the parent body of the Geminid Meteor Shower. Because of its small perihelion distance, Phaethon's surface reaches temperatures sufficient to destabilize hydrated materials. We conducted rotationally resolved spectroscopic observations of this asteroid, mostly covering the northern hemisphere and the equatorial region, beyond 2.5-micron to search for evidence of hydration on its surface. Here we show that the observed part of Phaethon does not exhibit the 3-micron hydrated mineral absorption (within 2-sigma). These observations suggest that Phaethon's modern activity is not due to volatile sublimation or devolatilization of phyllosilicates on its surface. It is possible that the observed part of Phaethon was originally hydrated and has since lost volatiles from its surface via dehydration, supporting its connection to the Pallas family, or it was formed from anhydrous material

Design of Carbon Composite Driveshaft for Ultralight Aircraft Propulsion System

This paper deals with the design of the carbon fibre composite driveshaft. This driveshaft will be used for connection between piston engine and propulsor of the type of axial-flow fan. Three different versions of driveshaft were designed and produced. Version 1 if completely made of Al alloy. Version 2 is of hybrid design where the central part is made of high strength carbon composite and flanges are made of Al alloy. Adhesive bond is used for connection between flanges and the central CFRP tube. Version 3 differs from the version 2 by aplication of ultrahigh-strength carbon fibre on the central part. Dimensions and design conditions are equal for all three versions to obtain simply comparable results. Calculations of driveshafts are described in the paper.

A 380 GHz SIS receiver using Nb/AlO(x)/Nb junctions for a radioastronomical balloon-borne experiment: PRONAOS

The superheterodyne detection technique used for the spectrometer instrument of the PRONAOS project will provide a very high spectral resolution (delta nu/nu = 10(exp -6)). The most critical components are those located at the front-end of the receiver: their contribution dominates the total noise of the receiver. Therefore, it is important to perform accurate studies for specific components, such as mixers and multipliers working in the submillimeter wave range. Difficulties in generating enough local oscillator (LO) power at high frequencies make SIS mixers very desirable for operation above 300 GHz. The low LO power requirements and the low noise temperature of these mixers are the primary reason for building an SIS receiver. This paper reports the successful fabrication of small (less than or equal to 1 sq micron) Nb/Al-O(x)/Nb junctions and arrays with excellent I-V characteristics and very good reliability, resulting in a low noise receiver performance measured in the 368/380 GHz frequency range

Combining Static and Dynamic Contract Checking for Curry

Static type systems are usually not sufficient to express all requirements on function calls. Hence, contracts with pre- and postconditions can be used to express more complex constraints on operations. Contracts can be checked at run time to ensure that operations are only invoked with reasonable arguments and return intended results. Although such dynamic contract checking provides more reliable program execution, it requires execution time and could lead to program crashes that might be detected with more advanced methods at compile time. To improve this situation for declarative languages, we present an approach to combine static and dynamic contract checking for the functional logic language Curry. Based on a formal model of contract checking for functional logic programming, we propose an automatic method to verify contracts at compile time. If a contract is successfully verified, dynamic checking of it can be omitted. This method decreases execution time without degrading reliable program execution. In the best case, when all contracts are statically verified, it provides trust in the software since crashes due to contract violations cannot occur during program execution.Comment: Pre-proceedings paper presented at the 27th International Symposium on Logic-Based Program Synthesis and Transformation (LOPSTR 2017), Namur, Belgium, 10-12 October 2017 (arXiv:1708.07854

From Boolean Equalities to Constraints

Although functional as well as logic languages use equality to discriminate between logically different cases, the operational meaning of equality is different in such languages. Functional languages reduce equational expressions to their Boolean values, True or False, logic languages use unification to check the validity only and fail otherwise. Consequently, the language Curry, which amalgamates functional and logic programming features, offers two kinds of equational expressions so that the programmer has to distinguish between these uses. We show that this distinction can be avoided by providing an analysis and transformation method that automatically selects the appropriate operation. Without this distinction in source programs, the language design can be simplified and the execution of programs can be optimized. As a consequence, we show that one kind of equational expressions is sufficient and unification is nothing else than an optimization of Boolean equality

Near-Earth asteroid (3200) Phaethon. Characterization of its orbit, spin state, and thermophysical parameters

The near-Earth asteroid (3200) Phaethon is an intriguing object: its perihelion is at only 0.14 au and is associated with the Geminid meteor stream. We aim to use all available disk-integrated optical data to derive a reliable convex shape model of Phaethon. By interpreting the available space- and ground-based thermal infrared data and Spitzer spectra using a thermophysical model, we also aim to further constrain its size, thermal inertia, and visible geometric albedo. We applied the convex inversion method to the new optical data obtained by six instruments and to previous observations. The convex shape model was then used as input for the thermophysical modeling. We also studied the long-term stability of Phaethon's orbit and spin axis with a numerical orbital and rotation-state integrator. We present a new convex shape model and rotational state of Phaethon: a sidereal rotation period of 3.603958(2) h and ecliptic coordinates of the preferred pole orientation of (319$^{\circ}$, $-$39$^{\circ}$) with a 5$^{\circ}$ uncertainty. Moreover, we derive its size ($D$=5.1$\pm$0.2 km), thermal inertia ($\Gamma$=600$\pm$200 J m$^{-2}$ s$^{-1/2}$ K$^{-1}$), geometric visible albedo ($p_{\mathrm{V}}$=0.122$\pm$0.008), and estimate the macroscopic surface roughness. We also find that the Sun illumination at the perihelion passage during the past several thousand years is not connected to a specific area on the surface, which implies non-preferential heating.Comment: Astronomy and Astrophysics. In pres

Deformation resistance and structure-forming processes of iron aluminides in hot rolling

We have developed simple mathematical models of mean equivalent stress dependence on temperature and strain for selected iron aluminides. Four similar melts with 16.5-19.2 wt.% of Al, 4 wt.% of Cr and with various contents of Ti and B were studied and compared. Flat specimens graded by thickness were hot rolled. Deformation resistance was calculated from the roll force values obtained using a laboratory mill Tandem. Postdynamic structure-forming processes of the tested aluminides, as well as their cracking susceptibility, were investigated by metallography. The differences in the deformation behavior and formability of the tested aluminides were described.Разработаны простые математические модели зависимости среднего эквивалентного напряжения от температуры и деформации для выбранных алюминидов железа. Были изучены и сравнены четыре одинаковые плавки, содержащие 16,5...19,2 вес.% Al, и 4 вес.% Сг и различное количество титана и бора. Плоские образцы, рассортированные по толщине, подвергались горячей прокатке. Сопротивление деформированию рассчитывали по величине усилия на валки, определенной с использованием лабораторного прокатного стана Тандем. Процессы структурообразования испытанных алюминидов после динамического воздействия и их склонность к трещинообразованию исследовали с использованием металлографии. Описаны наблюдавшиеся различия в поведении испытанных алюминидов при деформировании и в способности к формоизменению