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Tytuł:
BBC MICRO:BIT jako narzędzie nowoczesnej edukacji technicznej
BBC MICRO:BIT as a tool for modern technical education
Autorzy:
Szabłowski, Stanisław
Powiązania:
https://bibliotekanauki.pl/articles/2197617.pdf
Data publikacji:
2021-10-15
Wydawca:
Uniwersytet Rzeszowski
Tematy:
Micro:bit
programowanie Micro:bit
MakeCode
MicroPython
Micro:bitprogramming
Opis:
Micro:bit to płytka przeznaczona do nauki elektroniki i programowania dla dzieci i młodzieży. W opracowaniu przeprowadzono analizę sprzętową układu oraz środowisk programistycznych. Wskazano na możliwości zastosowania płytki Micro:bit w edukacji STEAM. W zakończeniu zamieszczono komentarze i wnioski praktyczne.
Micro:bit is a board designed for learning electronics and programming for children and teenagers. The study included a hardware analysis of the system and programming environments. The possibilities of using the Micro:bit board in STEAM education were indicated in the study. The conclusion includes comments and practical inferences.
Źródło:
Dydaktyka informatyki; 2021, 16; 168-174
2083-3156
2543-9847
Pojawia się w:
Dydaktyka informatyki
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Algorithm of adding the m-bit numbers
Algorytm dodający dwie m-bitowe liczby
Autorzy:
Woronowicz, K.
Powiązania:
https://bibliotekanauki.pl/articles/88412.pdf
Data publikacji:
2015
Wydawca:
Politechnika Białostocka. Oficyna Wydawnicza Politechniki Białostockiej
Tematy:
liczby m-bitowe
dodawanie liczb m-bitowych
algorytm
adding m-bit numbers
algorithm
m-bit numbers
Opis:
In the classic algorithm of adding two m-bit numbers with carries we add a single bits of the added numbers on each of the m positions. If we assume for a single iteration of the algorithm to calculate the value of a single bit of the sum, then for each pair of m-bit numbers the algorithm executes m iterations. In this paper we propose a recursive algorithm of adding two numbers for which the number of the executed iterations is variable and ranges from 0 to m.
W klasycznym algorytmie dodawania dwóch m-bitowych liczb z przeniesieniami dodajemy po kolei bity na poszczególnych pozycjach binarnych reprezentacji danych wejściowych. Jeśli przyjmiemy za iterację algorytmu wyznaczenie wartości pojedynczego bitu sumy, to dla każdej pary m-bitowych liczb algorytm wykonuje m iteracji. W niniejszej pracy proponujemy rekurencyjny algorytm dodawania dwóch liczb, który w pojedynczej iteracji wykonuje trzy operacje logiczne, a liczba iteracji wynosi od 0 do m.
Źródło:
Advances in Computer Science Research; 2015, 12; 95-108
2300-715X
Pojawia się w:
Advances in Computer Science Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Protection of Polish Investors under the China-Poland Bilateral Investment Treaty
Autorzy:
Wang, Peng
Żenkiewicz, Maciej
Powiązania:
https://bibliotekanauki.pl/articles/706917.pdf
Data publikacji:
2019-09-01
Wydawca:
Polska Akademia Nauk. Instytut Nauk Prawnych PAN
Tematy:
China-Poland BIT
investment protection
investment arbitration
Opis:
This article explores investment protection under Chinese international investment agreements (IIAs), particularly under the China-Poland bilateral investment treaty (BIT). As a state that both imports and exports foreign direct investment, China currently promotes balanced and safeguarded BITs that protect its increasing overseas investments and preserves the necessary space to regulate in the public interest. The Chinese government remains reluctant to be directly involved in investment arbitration as a respondent, while Chinese investors are active in taking advantage of the IIAs’ regime. When compared to China’s recent treaty practice and new developments in global investment governance, the China-Poland BIT is relatively outdated in terms of investment protection, promotion, social clauses, and dispute settlement. In terms of the investment protection effects of BITs, China is seemingly in a more urgent position to update the China-Poland BIT. However, if we evaluate the overall effects of a modernized BIT on investment promotion, regulation, and dispute settlement, an updated China-Poland BIT will fit the interests of both the Polish and Chinese governments. Notwithstanding the on-going negotiation between the EU and China, this article aims, along with presenting the Chinese practice regarding BITs, to describe de lege lata the state of protection offered to Chinese and Polish investors under the China-Poland BIT.
Źródło:
Polish Yearbook of International Law; 2018, 38; 141-163
0554-498X
Pojawia się w:
Polish Yearbook of International Law
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The analysis of technology of drilling with roller bits on the Carpathian foreland area in the years 1995-2011
Autorzy:
Rzyczniak, M.
Rajchel, G.
Powiązania:
https://bibliotekanauki.pl/articles/298894.pdf
Data publikacji:
2014
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
bits' exploitation
drilling technology parameters
bit performance
Opis:
In the article, there has been described results of the statistical analysis lead towards two groups of roller bits, with bit teeth, with diameters 0,216 m and 0,4445 m produced by Drilling Equipment and Device Company "GLINIK". Using these bits, there had been conducted a process of drilling holes on the Carpathian foreland area in the years 1995-2011. According to the analysis of a dispersion of measure points it was assigned linear regression equations and lead significance tests for values of the correlation factors and linear regression factors, drilling technology parameters dependency (weight on bit, rotational speed, product of normalized weight on bit and rotational speed, drilling mud capacity flow rate) and bit performances (rebore, drilling time, average rate of penetration), since the year in which analyzed bits were used. The results of the researches has been showed inthe form of charts of dispersion of measure points with lines and regression equations and lines of confidence intervals. The results of significance tests for correlation factors and linear regression factors has been inserted in tables. The purpose of lead analyses were acquiring information about changes of drilling technology parameters in a long period of time and about their influence on bit performances' values.
Źródło:
AGH Drilling, Oil, Gas; 2014, 31, 1; 135-147
2299-4157
2300-7052
Pojawia się w:
AGH Drilling, Oil, Gas
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Producing Random Bits with Delay-Line-Based Ring Oscillators
Autorzy:
Jessa, M.
Matuszewski, Ł.
Powiązania:
https://bibliotekanauki.pl/articles/227302.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
ring oscillator
jitter
random bit generator
combined generator
Opis:
One of the sources of randomness for a random bit generator (RBG) is jitter present in rectangular signals produced by ring oscillators (ROs). This paper presents a novel approach for the design of delays used in these oscillators. We suggest using delay elements made on carry4 primitives instead of series of inverters or latches considered in the literature. It enables the construction of many high frequency ring oscillators with different nominal frequencies in the same field programmable gate array (FPGA). To assess the unpredictability of bits produced by RO-based RBG, the restarts mechanism, proposed in earlier papers, was used. The output sequences pass all NIST 800-22 statistical tests for smaller number of ring oscillators than the constructions described in the literature. Due to the number of ROs with different nominal frequencies and the method of construction of carry4 primitives, it is expected that the proposed RBG is more robust to cryptographic attacks than RBGs using inverters or latches as delay element.
Źródło:
International Journal of Electronics and Telecommunications; 2013, 59, 1; 41-50
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Low Delay Sparse and Mixed Excitation CELP Coders for Wideband Speech Coding
Autorzy:
Dymarski, Przemysław
Powiązania:
https://bibliotekanauki.pl/articles/226657.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Low-Delay CELP
MP-MLQ
MOS
variable bit rate
Opis:
Code Excited Linear Prediction (CELP) algorithms are proposed for compression of speech in 8 kHz band at switched or variable bit rate and algorithmic delay not exceeding 2 msec. Two structures of Low-Delay CELP coders are analyzed: Low-delay sparse excitation and mixed excitation CELP. Sparse excitation is based on MP-MLQ and multilayer models. Mixed excitation CELP algorithm stems from the narrowband G.728 standard. As opposed to G.728 LD-CELP coder, mixed excitation codebook consists of pseudorandom vectors and sequences obtained with Long-Term Prediction (LTP). Variable rate coding consists in maximizing vector dimension while keeping the required speech quality. Good speech quality (MOS=3.9 according to PESQ algorithm) is obtained at average bit rate 33.5 kbit/sec.
Źródło:
International Journal of Electronics and Telecommunications; 2020, 66, 1; 69-76
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Population structure in the Penna model
Autorzy:
Sitarz, M.
Powiązania:
https://bibliotekanauki.pl/articles/1954644.pdf
Data publikacji:
2003
Wydawca:
Politechnika Gdańska
Tematy:
biological agein
Penna model
bit-string model
population structure
Opis:
Numerical simulations of growing population, based on the Penna model, are presented. We consider biological ageing as a result of the accumulation of mutations in the genotype. We present an example of simulated population structure and compare it with that of a real population. We also discuss the role of bad mutations threshold parameter T in the Penna model, to reproduce a smooth transition from the oversimplified logistic model (T --> ∞) to the Penna model.
Źródło:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2003, 7, 2; 263-269
1428-6394
Pojawia się w:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The questions of the dynamics of drilling bit on the surface of well bottom
Zagadnienia dynamiki narzędzi wiercących na powierzchnię dna otworu wiertniczego
Autorzy:
Burievich, T. J.
Powiązania:
https://bibliotekanauki.pl/articles/219369.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
górotwór
wiercenie
koronki wiertnicze
mining rock
drilling
drilling bit
Opis:
The purpose of this study was to investigate the dynamics of drilling bit on the well bottom as a function of their geometrical parameters. The frame of this method for this study includes former existed objective data on the unstable drilling devices as cantilever suspension. Research methods and calculation results are as follows: square coverage by tools blade working in different rotation regime; radius of the inscribed and circumscribed circle which leads to introduce and prospectively and solve problems on process optimization of mining rock at drilling the well bottom.
W artykule przedstawiono wyniki badań dynamiki narzędzia wiercącego podczas urabiania dna otworu wiertniczego w funkcji jego parametrów geometrycznych. Przedstawiona metoda badawcza oparta jest na dostępnych danych o występujących przypadkach niestabilnej pracy narzędzi wiercących. Metody badawcze i wyniki obliczeń są przedstawione w następujących obszarach: powierzchnia pokrycia przez ostrze narzędzia dla różnych prędkości obrotowych; problemy optymalizacji procesu urabiania skały na dnie otworu wiertniczego.
Źródło:
Archives of Mining Sciences; 2016, 61, 2; 275-283
0860-7001
Pojawia się w:
Archives of Mining Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Generating Pseudorandom S-Boxes - a Method of Improving the Security of Cryptosystems Based on Block Ciphers
Autorzy:
Mroczkowski, P.
Powiązania:
https://bibliotekanauki.pl/articles/308900.pdf
Data publikacji:
2009
Wydawca:
Instytut Łączności - Państwowy Instytut Badawczy
Tematy:
block cipher
pseudorandom bit generator
substitution box (S-box)
Opis:
The paper presents a general framework for improving the security of the cryptosystem based on the symmetric block cipher. The main idea is based on possibility of chancing substitution boxes (called S-boxes) in encryption/decryption algorithm. In order to make it possible, it is necessary to generate identical boxes by an encryption and decryption party. This is the main reason, why deterministic methods of generating substitution boxes based on the pseudorandom sequences will be presented.
Źródło:
Journal of Telecommunications and Information Technology; 2009, 2; 74-79
1509-4553
1899-8852
Pojawia się w:
Journal of Telecommunications and Information Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Audio Compression using a Modified Vector Quantization algorithm for Mastering Applications
Autorzy:
Prince, Shajin
D, Bini
Kirubaraj, Alfred A.
Immanuel, Samson J.
M, Surya
Powiązania:
https://bibliotekanauki.pl/articles/27311916.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
vector quantization
scalable
perceptual coder
audio mastering
bit stream
Opis:
Audio data compression is used to reduce the transmission bandwidth and storage requirements of audio data. It is the second stage in the audio mastering process with audio equalization being the first stage. Compression algorithms such as BSAC, MP3 and AAC are used as standards in this paper. The challenge faced in audio compression is compressing the signal at low bit rates. The previous algorithms which work well at low bit rates cannot be dominant at higher bit rates and vice-versa. This paper proposes an altered form of vector quantization algorithm which produces a scalable bit stream which has a number of fine layers of audio fidelity. This modified form of the vector quantization algorithm is used to generate a perceptually audio coder which is scalable and uses the quantization and encoding stages which are responsible for the psychoacoustic and arithmetical terminations that are actually detached as practically all the data detached during the prediction phases at the encoder side is supplemented towards the audio signal at decoder stage. Therefore, clearly the quantization phase which is modified to produce a bit stream which is scalable. This modified algorithm works well at both lower and higher bit rates. Subjective evaluations were done by audio professionals using the MUSHRA test and the mean normalized scores at various bit rates was noted and compared with the previous algorithms.
Źródło:
International Journal of Electronics and Telecommunications; 2023, 69, 2; 287--292
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Experimental study of layouts of PDC cutters in core bit drilling
Autorzy:
Buitrago Gomez, L. A.
Miska, S. Z.
Ziaja, M. B.
Powiązania:
https://bibliotekanauki.pl/articles/299255.pdf
Data publikacji:
2016
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
PDC cutter
cutters layout
PDC bit
coring
drilling efficiency
Opis:
Over the past two decades, various single cutter force models have been developed that consider formation properties and bit characteristics. These models have been extensively used to describe the interaction of a Polycrystalline Diamond Compact (PDC) bit with formation rocks; however, their use to predict bit drilling efficiency is usually inadequate. There is an ample of field evidence that the density and layouts of PDC cutters affect drilling efficiency. Still, however, there is no reliable model of the PDC bit performance allowing determination of these bit design features for a specific bit's applications. In order to better understand the relationship between rock properties and PDC cutter layouts for different bit applications, laboratory drilling tests were performed with PDC core bits. The concept of an eight-blade PDC core bit was used to build a bit with a common body and replaceable heads. Core-bit design features such as: bit, cutter size, and cutter geometry were constant. In this study, the full-scale test rig facility at the University of Tulsa was used to obtain consistent data for six different layouts of PDC cutters. Operating parameters, such as the rate per minute (RPM) and weight on bit (WOB), were varied and performance parameters (rate of penetration (ROP) and bit torque (TQB)), were measured at each time step with the frequency of 10 Hz. The ROP were calculated as a function of bit displacement over time. All operating parameters were recorded as part of the data acquisition platform. Depth of Cut (DOC) was calculated from ROP, and the average WOB and TQB were estimated at each depth of cut. Tests were performed on two different rocks: Bedford and Carthage Limestones. For the purpose of comparing performance among different cutter layouts, we experiment with a maximum of four different depths of cut, which corresponded to four different weights on bit. The tested layouts allowed a constant maximum DOC per cutter of 0.25 in. Water was the drilling fluid for the entire experimental phase. The results showed that under the same drilling parameters, the cutter layout plays a key role in drilling efficiency. Strong linear relationships were found between DOC, WOB and TQB at different conditions that were characteristic of the specific bit design. Also, the PDC cutter layouts affected the relative drilling performance differently for different rock properties.
Źródło:
AGH Drilling, Oil, Gas; 2016, 33, 2; 341-360
2299-4157
2300-7052
Pojawia się w:
AGH Drilling, Oil, Gas
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Konwencja singapurska a rozwiązywanie sporów inwestycyjnych
Autorzy:
Kożuch, Małgorzata
Powiązania:
https://bibliotekanauki.pl/articles/2216587.pdf
Data publikacji:
2021-04-27
Wydawca:
Uniwersytet Warszawski. Wydawnictwo Naukowe Wydziału Zarządzania
Tematy:
arbitraż
mediacja
konwencja singapurska
rozwiązywanie sporów
ADR
inwestycje
BIT
Opis:
Międzynarodowa przestrzeń prawna wzbogaciła się w roku 2020 nowym instrumentem prawnym, jakim jest konwencja singapurska o mediacji. Jej zastosowanie w polubownym rozwiązywaniu sporów zależne jest od aktywności państw oraz UE, które mogą do niej przystąpić lub pozostać poza obszarem jej oddziaływania. Na rynku prawnym UE po wydaniu przez TSUE orzeczenia C-284/16 wejście w życie konwencji mogłoby uzupełnić przestrzeń o instrument, który spełnia podobne cele do orzecznictwa sądów arbitrażowych w sprawach inwestycyjnych. Przejecie tego instrumentu wymaga jednak myślenia poza dotychczasowym schematem rozwiązań prawnych.
Źródło:
internetowy Kwartalnik Antymonopolowy i Regulacyjny; 2021, 10, 3; 91-107
2299-5749
Pojawia się w:
internetowy Kwartalnik Antymonopolowy i Regulacyjny
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Efficiency of drilling large diameter wells with cutter bits on Szczerców opencast
Autorzy:
Macuda, J.
Powiązania:
https://bibliotekanauki.pl/articles/299131.pdf
Data publikacji:
2015
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
drilling of wells
cutter bit
dewatering of rock mass
lignite
Opis:
Drilling of large diameter wells to be used for dewatering of lignite deposits is inefficient due to the presence of large packages of loose Quaternary and Tertiary strata. Moreover, considerable dewatering of the rock mass favors serious complications and drilling break-downs connected with the sliding of wellbore walls. Accordingly, new technical and technological solutions, which enable faster drilling, are searched for. In this way the time of operation of drilling mud on the near-wellbore zone can be shortened and the safety of drilling works increased. For the sake of obtaining higher rates of drilling in large diameter dewatering wellbores a new cutter bit 0.96 m of diameter was designed. Drillability tests in industrial conditions followed. These tests were performed in separated, loose and low-compaction, macroscopically homogeneous rocks of similar drillability. The tests were performed on selected sections 0.3 to 1.0 m long, and each of the sections was drilled at constant rotational velocity and weight on bit. Prior to these tests there were established limitations regarding weight on bit and rotational velocity of the bit, in reference to the technical characteristic of the rig, strength of the string and the cutter bit. Two different regression models were considered to find a dependence of mechanical drilling rate on weight on bit and rotational velocity of the bit for selected macroscopically homogeneous strata. The most favorable results were obtained for a power model representing impact of axial stress and rotational velocity of the bit on the drilling rate. They have been confirmed by calculated regression coefficients and statistical parameters. Industrial tests were performed to assess the efficiency of drilling large diameter dewatering wells with a cutter bit of 0.96 m diameter on the basis of the presented model of average drilling rate. The results for the average drilling rate turned out to be much higher than the ones obtained so far.
Źródło:
AGH Drilling, Oil, Gas; 2015, 32, 2; 405-413
2299-4157
2300-7052
Pojawia się w:
AGH Drilling, Oil, Gas
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Pseudo-random bit generators based on linear-feedback shift registers in a programmable device
Autorzy:
Parol, M.
Dąbal, P.
Szplet, R.
Powiązania:
https://bibliotekanauki.pl/articles/114462.pdf
Data publikacji:
2016
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
pseudo-random bit generators
linear-feedback shift register
programmable device
Opis:
We present the results of comparative study on three pseudo-random bit generators (PRBG) based on various use of linear-feedback shift registers (LFSR). The project was focused on implementation and tests of three such PRBG in programmable device Spartan 6, Xilinx. Tests of the designed PRBGs were performed with the use of standard statistical tests NIST SP800-22.
Źródło:
Measurement Automation Monitoring; 2016, 62, 6; 184-186
2450-2855
Pojawia się w:
Measurement Automation Monitoring
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analiza wpływu parametrów wiercenia na zużycie uzbrojenia świdrów gryzowych
Analysis of drilling parameters influence on drilling bits equipment wear
Autorzy:
Jaremek, P.
Czerniec, M.
Powiązania:
https://bibliotekanauki.pl/articles/395461.pdf
Data publikacji:
2011
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
wiertnictwo
świder gryzowy
trwałość
zużycie
drilling
drilling bit
durability
wear
Opis:
Przedstawiono wyniki oceny wpływu prędkości obrotowej wiercenia oraz obciążenia osiowego na zużycie elementów uzbrojenia świdra trójgryzowego w oparciu o opracowany dla niego model kinetyki kontaktu tribologicznego z urabianą calizną. Przeprowadzono analizę obliczeniową wspomnianych parametrów, wyniki podano w postaci graficznej.
The article presents the results of impact assessment drilling speed and axial load on the wear of tricone bit equipment based on a model developed for the kinetics of tribological contact with the mining undisturbed soil. An analysis of the calculation of these parameters, the results are given in graphic form.
Źródło:
Postępy Nauki i Techniki; 2011, 10; 61-71
2080-4075
Pojawia się w:
Postępy Nauki i Techniki
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Implementation of C-PolSK Modulation in FSO Network and Analysis of its Atmospheric Performance
Autorzy:
Chattopadhyay, Diptangshu
Bharti, Manisha
Powiązania:
https://bibliotekanauki.pl/articles/309433.pdf
Data publikacji:
2019
Wydawca:
Instytut Łączności - Państwowy Instytut Badawczy
Tematy:
attenuation
bit error rate
circular polarization shift keying
quality factor
Opis:
Free Space Optical (FSO) communication is a quickly developing technology that is designed to handle high data rates while maintaining a good quality factor (Q-factor). Many novel techniques have been implemented to cope with atmospheric attenuating factors, such as fog and rain. Here, we have introduced circular polarization shift keying (C-PolSK) modulation to produce a stable and uniform light beam. The plane of polarized light keeps rotating along with the propagation vector, which helps reduce phase variations and cross-channel effects. C-PolSK provides higher penetrating power and attenuation resistance over linear polarization shift keying (L-PolSK). Two different C-PolSK models have been proposed and graphical comparisons, relying on such parameters as Q-factor, transmission distance and inputoutput power, have been made. The cases of moderate fog and rain attenuation are taken to verify the model’s efficiency. Polarized light is split into two orthogonal components and then modulated using the Mach-Zehnder modulator. One of the models also employs the principle of orthogonal differential phase shifting. Eye diagrams have been provided to verify the bit error rate (BER). The orthogonal differential phase shifted C-PolSK model proves to be the most suitable implementation prototype.
Źródło:
Journal of Telecommunications and Information Technology; 2019, 4; 43-49
1509-4553
1899-8852
Pojawia się w:
Journal of Telecommunications and Information Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
OFDM for Cognitive Radio Systems : Novel Power Allocation and Bit Loading Algorithms
Autorzy:
Razmi, Shirin
Parhizgar, Naser
Powiązania:
https://bibliotekanauki.pl/articles/227256.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
cognitive radio
OFDM
interference constraints
power allocation
adaptive modulation
bit loading
Opis:
A novel method to improve the performance of the frequency band is cognitive radio that was introduced in 1999. Due to a lot of advantages of the OFDM, adaptive OFDM method, this technique is used in cognitive radio (CR) systems, widely. In adaptive OFDM, transmission rate and power of subcarriers are allocated based on the channel variations to improve the system performance. This paper investigates adaptive resource allocation in the CR systems that are used OFDM technique to transmit data. The aim of this paper is to maximize the achievable transmission rate for the CR system by considering the interference constraint. Although secondary users can be aware form channel information between each other, but in some wireless standards, it is impossible for secondary user to be aware from channel information between itself and a primary user. Therefore, due to practical limitation, statistical interference channel is considered in this paper. This paper introduces a novel suboptimal power allocation algorithm. Also, this paper introduces a novel bit loading algorithm. In the numerical results sections, the performance of our algorithm is compared by optimal and conventional algorithms. Numerical results indicate our algorithm has better performance than conventional algorithms while its complexity is less than optimal algorithm.
Źródło:
International Journal of Electronics and Telecommunications; 2019, 65, 1; 139-145
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Image encryption combining discrete fractional angular transform with Arnold transform in image bit planes
Autorzy:
Zhou, Z.
Yu, J.
Liao, Q.
Gong, L.
Powiązania:
https://bibliotekanauki.pl/articles/173704.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
Arnold transform
bit plane
discrete fractional angular transform
image encryption algorithm
Opis:
A new image encryption algorithm by using a discrete fractional angular transform and Arnold transform in image bit planes is investigated. In the image encryption algorithm, the original image is encrypted by the Arnold transform in image bit planes firstly, and then the resulting image is encrypted by the discrete fractional angular transform further. The key of the image encryption algorithm includes the parameters of the Arnold transform and the order of the discrete fractional angular transform. It is shown that the proposed image encryption algorithm is of high security and strong enough to counteract some conventional image attack manners.
Źródło:
Optica Applicata; 2018, 48, 2; 225-236
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Transmitter Inclination Angle Characteristics for Underwater Optical Wireless Communication in a Variety of APD Detectors
Autorzy:
Mazin, Ali A. Ali
Powiązania:
https://bibliotekanauki.pl/articles/1192197.pdf
Data publikacji:
2016
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Communications
Underwater Optical Communications
Avalanche Photodiode
Bit Error Rate
Channel Capacity
Opis:
In this paper, the performance of an underwater optical wireless communications system is theoretically analyzed, using 4-PPM modulation technique and an avalanche photodiodes APD receiver over underwater environment channels. Based on the line of sight (LOS) geometrical model for optical beam propagation horizontally on an underwater medium and combined with signal to noise ratio model for Si, Ge and InGaAs APD and BER; then the impacts of the distance of transmission, power of the transmitter under Jerlov water types (I, IA, IB) are analyzed. The characteristics of bit error rate BER and channel capacity for 4-PPM optical modulation technique are studied under different APD detector and Jerlov water types. Simulation results indicate that the performance of PPM and Jerlov type (I) are more suited for an underwater optical wireless communication. On the other hand, we discuss the suitability of avalanche photodiodes under this modulation technique, where the photodiode Si APD has more advantage compared with the other detectors when used as a receiver in an underwater optical communication.
Źródło:
World Scientific News; 2016, 45, 2; 355-372
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Performance Analysis of Hybrid Phase Shift Keying over Generalized Nakagami Fading Channels
Autorzy:
Youssuf, M.
Abdelmageed, M. Z.
Powiązania:
https://bibliotekanauki.pl/articles/308527.pdf
Data publikacji:
2010
Wydawca:
Instytut Łączności - Państwowy Instytut Badawczy
Tematy:
bit error rate
hybrid phase shift keying
quadrature phase shift keying
Opis:
In addition to the benefits of hybrid phase shift keying (HPSK) modulation in reducing the peak to average power ratio of the transmitted signal to reduce the zero cross- ings and the 0?-degree phase transmissions, HPSK enhances the bit error rate (BER) measure of the signal performance. The constellation of the HPSK is analyzed, and an expression for the conditional probability of HPSK modulation over additive white Gaussian noise (AWGN) is derived. This BER measure of HPSK is shown to outperform quadrature phase shift keying (QPSK) modulation. HPSK performance through Nakagami - m fading channel is also considered.
Źródło:
Journal of Telecommunications and Information Technology; 2010, 3; 77-82
1509-4553
1899-8852
Pojawia się w:
Journal of Telecommunications and Information Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The 2D-steganography method based on analysis of two adjacent LSB
Autorzy:
Dobryakova, L.
Ochin, E.
Powiązania:
https://bibliotekanauki.pl/articles/360114.pdf
Data publikacji:
2014
Wydawca:
Akademia Morska w Szczecinie. Wydawnictwo AMSz
Tematy:
steganography
container
embedding of dates
stego-message
Least Significant Bit
LSB
Opis:
In computing, the Least Significant Bit (LSB) is the bit position in a binary integer giving the units value, that is, determining whether the number is even or odd. We do not use this format. In conventional Intel bit ordering, the Most Significant Bit (MSB) is numbered 7 and the least significant bit (LSB) is numbered 0: 2⁷ (MSB) 2⁶ 2⁵ 2⁴ 2³ 2² 2¹ 2⁰ (LSB) D = d7 d6 d5 d4 d3 d2 d1 d0 For example, if on the record of number D = 131 = 10000011 we invert the MSB = 1 into MSB = 0, then obtain D = 00000011 = 3, but if we invert LSB = 1 into LSB = 0, then distortions are considerably fewer: D = 10000010 = 130. It is common to assign each bit a position number, ranging from zero to N – 1, where N is the number of bits in the binary representation used. Normally, this is simply the exponent for the corresponding bit weight in base-2 (such as in 2⁷, 2⁶, …, 2¹, 2⁰). In this article to reduce the stego-errors we use a pair of numbers D₁ and D₂ and a pair of corresponding LSB d₁,₀ and d₂,₀.
Źródło:
Zeszyty Naukowe Akademii Morskiej w Szczecinie; 2014, 40 (112); 95-99
1733-8670
2392-0378
Pojawia się w:
Zeszyty Naukowe Akademii Morskiej w Szczecinie
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Angola–Brazil Bilateral Investment Treaty: an introduction to its dispute settlement mechanism
Autorzy:
Alcici, Lucas Moreira
Powiązania:
https://bibliotekanauki.pl/articles/1834991.pdf
Data publikacji:
2021
Wydawca:
Krakowska Akademia im. Andrzeja Frycza Modrzewskiego
Tematy:
Angola–Brazil BIT
foreign investment
expropriation
dispute settlement
State-State arbitration
Opis:
This article presents an overview of the Angola–Brazil BIT and briefly analyses the dispute settlement mechanism for investment disputes provided for by that agreement. The ratification of the BIT by Brazil a few years ago means that Brazilian investors are now able to seek protection to their investments in Angola through the bilateral dispute settlement mechanism established by the BIT. Although Investor-State arbitration is not envisaged in the agreement, Brazilian investors can request Brazil to act on their behalf bringing their claims before the Joint Committee for conciliation and, if this proves unsuccessful, initiating State-State arbitration proceedings against Angola.
Źródło:
Studia Prawnicze: rozprawy i materiały; 2021, (28), 1; 71-77
1689-8052
2451-0807
Pojawia się w:
Studia Prawnicze: rozprawy i materiały
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Hybrid PAPR reduction schemes for different OFDM-based VLC systems
Autorzy:
El-Ganiny, Mohamed Y.
Khalaf, Ashraf A. M.
Hussein, Aziza I.
Hamed, Hesham F. A.
Powiązania:
https://bibliotekanauki.pl/articles/2174839.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Stowarzyszenie Elektryków Polskich
Tematy:
visible light communication
peak-to-average power ratio
bit error rate
Opis:
Orthogonal frequency division multiplexing has been widely used in many radio frequency wireless communication standards as a preferable multicarrier modulation scheme. The modulated signals of a conventional orthogonal frequency division multiplexing system are complex and bipolar. In intensity-modulated direct detection optical wireless communications, transmitted signals should be real and unipolar due to non-coherent emissions of an optical light emitting diode. In this paper, different hybrid optical systems have been proposed to satisfy real and unipolar signals. Peak-to-average power ratio is one of the biggest challenges for orthogonal frequency division multiplexing-based visible light communications. They are based on a combination of non-linear companding techniques with spreading or precoding techniques. Simulation evaluation is performed under direct current-biased optical orthogonal frequency division multiplexing, asymmetrically clipped optical orthogonal frequency division multiplexing, and Flip-orthogonal frequency division multiplexing systems in terms of peak-to-average power ratio, bit error rate, and spectral efficiency. The proposed schemes are investigated to determine a scheme with a low peak-to-average power ratio and an acceptable bit error rate. MATLABTM software has been successfully used to show the validity of the proposed schemes.
Źródło:
Opto-Electronics Review; 2022, 30, 3; art. no. e141951
1230-3402
Pojawia się w:
Opto-Electronics Review
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Hybrid PAPR reduction schemes for different OFDM-based VLC systems
Autorzy:
El-Ganiny, Mohamed Y.
Khalaf, Ashraf A. M.
Hussein, Aziza I.
Hamed, Hesham F. A.
Powiązania:
https://bibliotekanauki.pl/articles/2174840.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Stowarzyszenie Elektryków Polskich
Tematy:
visible light communication
peak-to-average power ratio
bit error rate
Opis:
Orthogonal frequency division multiplexing has been widely used in many radio frequency wireless communication standards as a preferable multicarrier modulation scheme. The modulated signals of a conventional orthogonal frequency division multiplexing system are complex and bipolar. In intensity-modulated direct detection optical wireless communications, transmitted signals should be real and unipolar due to non-coherent emissions of an optical light emitting diode. In this paper, different hybrid optical systems have been proposed to satisfy real and unipolar signals. Peak-to-average power ratio is one of the biggest challenges for orthogonal frequency division multiplexing-based visible light communications. They are based on a combination of non-linear companding techniques with spreading or precoding techniques. Simulation evaluation is performed under direct current-biased optical orthogonal frequency division multiplexing, asymmetrically clipped optical orthogonal frequency division multiplexing, and Flip-orthogonal frequency division multiplexing systems in terms of peak-to-average power ratio, bit error rate, and spectral efficiency. The proposed schemes are investigated to determine a scheme with a low peak-to-average power ratio and an acceptable bit error rate. MATLABTM software has been successfully used to show the validity of the proposed schemes.
Źródło:
Opto-Electronics Review; 2022, 30, 3; art. no. e141951
1230-3402
Pojawia się w:
Opto-Electronics Review
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Implementing Achmea: The Quest for Fundamental Change in International Investment Law
Autorzy:
Kułaga, Łukasz
Powiązania:
https://bibliotekanauki.pl/articles/706832.pdf
Data publikacji:
2020-10-26
Wydawca:
Polska Akademia Nauk. Instytut Nauk Prawnych PAN
Tematy:
Achmea
bilateral investment treaty
BIT
conflict of treaties
European Union
ISDS
VCLT
Opis:
The judgment of the Court of Justice in the Achmea case evoked significant repercussions regarding the application and operation of the bilateral investment treaties (BITs) concluded between EU Member States. As a result of this decision, EU Member States have decided to terminate almost 190 intra-EU BITs. Nevertheless, full implementation of the Achmea judgment remains a complex issue, entangled in political and legal controversies concerning intra-EU BITs which have been present for more than a decade. On a more general level, the implementation process is simultaneously entwined in two other significant debates: the specifics of the rights of investors, and the relationship between EU law and international law.
Źródło:
Polish Yearbook of International Law; 2019, 39; 227-250
0554-498X
Pojawia się w:
Polish Yearbook of International Law
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-25 z 80

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