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Number of results: 21
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Abstract

“Soon we will be able to fit the contents of the Encyclopedia Britannica on a head of a pin,” the famous physicist Richard Feynman argued back in the 1960s. Perhaps even he would be amazed at the possibilities now offered by carbon nanotubes, several hundred thousand times tinier than a pin. Their amazing properties have been exploited in an integrated circuit developed at the Karlsruhe Institut für Technologie.

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Authors and Affiliations

Karolina Słowik
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Abstract

Zjednej strony nowe rekordy sportowe i podbój kosmosu. Z drugiej – bezbronność wobec skutków zmian klimatu czy nowych wirusów. O zdolnościach adaptacyjnych ludzkiego organizmu opowiada prof. Andrzej W. Ziemba.
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Authors and Affiliations

Andrzej W. Ziemba
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Abstract

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China’s recent treaty practice and new developments in global investment governance, the China-Poland BIT is relatively outdated in terms of investment protection, promotion, social clauses, and dispute settlement.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.

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Authors and Affiliations

Peng Wang
Maciej Żenkiewicz
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Abstract

This article examines the consequences of the Court of Justice of the European Union’s (CJEU) ruling in Achmea concerning Investor-State Arbitration (ISA) under intra- EU Bilateral Investment Treaties (BITs) from a treaty law perspective. It begins by briefly setting out the arguments of Advocate General Wathelet and the CJEU supporting their different positions on whether intra-EU BITs ISA clauses are compatible with EU law. The article then proceeds to analyse Achmea’s implications for intra-EU BIT ISA. It concludes that, as a result of the CJEU’s ruling, arbitral tribunals are deprived of their jurisdiction to entertain investors’ claims brought under intra-EU BIT ISA clauses. Finally, the article argues that Achmea’s applicability to cases brought under intra-EU BIT ISA clauses is limited, using the application of EU law as a relevant qualification. In order for an arbitral tribunal to be deprived of its jurisdictional competence as a result of Achmea, it must be entitled to interpret and apply EU law directly or indirectly in determining its jurisdiction.

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Authors and Affiliations

Konstantina Georgaki
Thomas-Nektarios Papanastasiou
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Abstract

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.
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Bibliography

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Authors and Affiliations

Mohamed Y. El-Ganiny
1
Ashraf A. M. Khalaf
2
ORCID: ORCID
Aziza I. Hussein
3
ORCID: ORCID
Hesham F. A. Hamed
4

  1. Department of Electrical Engineering, Higher Technological Institute, 10th of Ramadan City, Sharqia, Egypt
  2. Department of Electrical Engineering, Faculty of Engineering, Minia University, Minia 61519, Egypt
  3. Electrical and Computer Engineering Department, Effat University, Jeddah, Kingdom of Saudi Arabia
  4. Department of Telecommunications Engineering, Egyptian Russian University, Badr City, Egypt
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Abstract

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.

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Authors and Affiliations

Przemysław Dymarski
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Abstract

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.
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Authors and Affiliations

Shajin Prince
1
Bini D
1
A Alfred Kirubaraj
1
J Samson Immanuel
1
Surya M
1

  1. Karunya Institute of Technology and Sciences, Coimbatore, India
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Abstract

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.

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Authors and Affiliations

Shirin Razmi
Naser Parhizgar
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Abstract

In this study, we propose a novel keyed hash algorithm based on a Boolean function and chaotic attractor. The hash algorithm called BentSign is based on two Signature attractors and XOR function and a bent Boolean function. The provided theoretical and experimental results confirm that the novel scheme can generate output hashes with a good level of security, collision resistance, and protection against most common attacks.

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Authors and Affiliations

M. Todorova
B. Stoyanov
K. Szczypiorski
W. Graniszewski
K. Kordov
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Abstract

A novel non-orthogonal multiple access (NOMA) scheme is proposed to improve the throughput and the outage probability of the cognitive radio (CR) inspired system which has been implemented to adapt multiple services in the nextgeneration network (5G). In the proposed scheme, the primary source (PS) had sent a superposition code symbol with a predefined power allocation to relays, it decoded and forwarded (DF) a new superposition coded symbol to the destination with the other power allocation. By using a dual antenna at relays, it will be improved the bandwidth efficiency in such CR NOMA scheme. The performance of the system is evaluated based on the outage probability and the throughput with the assumption of the Rayleigh fading channels. According to the results obtained, it is shown that the outage probability and throughput of the proposed full-duplex (FD) in CR-NOMA with reasonable parameters can be able deploy in practical design as illustration in numerical results section.

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Authors and Affiliations

Thanh-Nam Tran
Dinh-Thuan Do
Miroslav Voznak
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Abstract

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.

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Authors and Affiliations

Łukasz Kułaga
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Abstract

Vehicular visible light communication is an emerging technology that allows wireless communication between vehicles or between vehicles and infrastructure. In this paper, a vehicular visible light communication system is designed using a non-return to zero on-off keying modulation scheme under the effect of different weather conditions such as clear, haze, and fog. The first model is a light emitting diode-based system and the second is a laser diode-based system. For both models, the influence of system parameters such as beam divergence, transceiver aperture diameters, and receiver responsivity is studied. The impact of the use of the trans-impedance amplifier is also investigated for both models. It was concluded that in the presence of the amplifier, output power of the light emitting diode and laser diode model are increased by 98.46 µW and 0.4719 W, respectively. The performance of the two proposed models is evaluated through bit error rate, quality factor, eye diagram, and output power to have some insightful results about the quality of service for the two proposed models. Under a specific weather condition, the performance of the system would be critical and other techniques should be applied. The maximum achievable link distance for the laser-based and light-emitting diode-based systems is 190 m at a data rate of 25 Gbps and 80 m at a data rate of 60 kbps, respectively, under the same system parameters and weather conditions. The obtained results provide a full idea about the availability of constructing our proposed model in a practical environment, showing a higher performance of the laser diode-based model than that of the light emitting diode-based model.
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Authors and Affiliations

Eslam S. El-Mokadem
1
Nagwan I. Tawfik
1
Moustafa H. Aly
2
ORCID: ORCID
Walid S. El-Deeb
3

  1. Department of Electronics and Communications Engineering, Higher Technological Institute, 10th of Ramadan City, Egypt
  2. Arab Academy for Science, Technology and Maritime Transport, 1029 Alexandria, Egypt
  3. Department of Electronics and Communications Engineering, Zagazig University, 44519 Zagazig, Egypt
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Abstract

Peak-to-average power ratio reduction techniques for visible light communication broadcasting systems are designed, simulated, and evaluated in this work. The proposed techniques are based on merging non-linear companding techniques with precoding techniques. This work aims to nominate an optimum novel scheme combining the low peak-to-average power ratio with the acceptable bit error rate performance. Asymmetrically clipped optical orthogonal frequency division multiplexing with the low peak-to-average power ratio performance becomes more attractive to real-life visible light communication applications due to non-linearity elimination. The proposed schemes are compared and an optimum choice is nominated. Comparing the presented work and related literature reviews for peak-to-average power ratio reduction techniques are held to ensure the proposed schemes validity and effectiveness.
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Authors and Affiliations

Nazmi A. Mohammed
1
Mohamed M. Elnabawy
2 3
Ashraf A. M. Khalaf
2
ORCID: ORCID

  1. Photonic Research Lab, Electrical Engineering Department, College of Engineering, Shaqra University, Dawadmi 11961, Kingdom of Saudi Arabia
  2. Electrical Engineering Department, Faculty of Engineering, Minia University, Minia, Egypt, P.O. Box 61111, Minia, Egypt
  3. Electronics and Communication Department, Modern Academy for Engineering and Technology, Maadi 11585, Cairo, Egypt
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Abstract

The presented work proposes a new dimming control schemes for indoor visible light communication which combines variable pulse-position modulation, colour shift keying as key schemes of IEEE 802.15.7 standard, and sub carrier-pulse-position modulation as a pulse-position modulation variant with orthogonal frequency division multiplexing. These schemes are then compared with traditional merging schemes utilizing pulse-width modulation and multiple pulse-position modulation with m-ary quadrature amplitude modulation OFDM. The proposed schemes are investigated in a typical room with a different lighting layout (i.e., distinctive and uniform lighting layout), followed by an illumination investigation to evaluate the performance of the proposed schemes, especially the enhanced achieved data rates, and to determine their limitations as reliable visible light communication systems that can satisfy both communication and illumination requirements.

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Authors and Affiliations

Nazmi A. Mohammed
Kareem A. Badawi
Ashraf A. M. Khalaf
S. El-Rabaie
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Abstract

Atmospheric turbulence is considered as major threat to Free Space Optical (FSO) communication as it causes irradiance and phase fluctuations of the transmitted signal which degrade the performance of FSO system. Wavelength diversity is one of the techniques to mitigate these effects. In this paper, the wavelength diversity technique is applied to FSO system to improve the performance under different turbulence conditions which are modeled using Exponentiated Weibull (EW) channel. In this technique, the data was communicated through 1.55 μm, 1.31 μm, and 0.85 μm carrier wavelengths. Optimal Combining (OC) scheme has been considered to receive the signals at receiver. Mathematical equation for average BER is derived for wavelength diversity based FSO system. Results are obtained for the different link length under different turbulence conditions. The obtained average BER results for different turbulence conditions characterized by EW channel is compared with the published result of average BER for different turbulence which is presented by classical channel model. A comparative BER analysis shows that maximum advantage of wavelength diversity technique is obtained when different turbulence conditions are modeled by EW channel.
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Authors and Affiliations

Dhaval Shah
1
Hardik Joshi
1
Dilipkumar Kothari
1

  1. Faculty of Electronics and Communication Engineering, Institute of Technology, Nirma University, Ahmedabad, India
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Abstract

The major difference between a continuous mode optical regenerator (CMOR) and a burst mode optical regenerator (BMOR) is that a BMOR is capable of handling large variations in the input power which makes it useful in optical packet switched and optical burst switched networks. This is due to the optical limiting amplifier (OLA) present in the BMOR. Using computer modelling, the impact of using different OLA non-linear transfer functions on the output bit error rate of a system consisting of a cascade of 2R BMORs has been investigated. The effect of amplified spontaneous emission (ASE) noise introduced in the inter-regenerator links has also been taken into consideration. Also, a brief review of existing OLA designs is presented.
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Authors and Affiliations

Yash Deodhar
1
Jeeru Jaya Sankar Reddy
1
Priyanka Desai Kakade
2
Rohan Kakade
3

  1. Manipal Institute of Technology, Manipal Academy of Higher Education, Manipal, Karnataka, India-576104
  2. Department of Electronics And Communication Engineering, Manipal Institute of Technology, Manipal Academy of Higher Education, Manipal, Karnataka, India-576104
  3. Loughborough University, United Kingdom
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Abstract

The dual core bit-byte CPU must be equipped with properly designed circuits, providing interface between the two processor units, and making it possible to exploit all its advantages like versatility of the byte unit and speed of the bit unit. First of all, the interface circuits should be designed in such a way, that they don’t disturb maximally parallel operation of the units, and that the CPU as a whole works in the same manner as in a standard PLC. The paper presents hardware solutions supporting effective operation of PLC CPU-s. Possibilities of solving problems concerning data exchange between a CPU and peripheral circuits were presented, with a special stress on timers and counters, and also on data exchange between the bit unit and the byte unit. The objective of the proposed solutions is to decrease the time necessary for a CPU to access its peripheries.

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Authors and Affiliations

M. Chmiel
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Abstract

Non-Orthogonal Multiple Access (NOMA) in the fifth generation (5G) system is one of the optimistic technologies for wireless radio access networks. Compared to orthogonal multiple accesses (OMA) reduce the spectral efficiency; NOMA provides the best solution by increasing the data rates. This study evaluates NOMA with a downlink in the automatic deployment of multiusers. The outage performance and ergotic sum-rate gain give the NOMA better performance can be concluded at the final results. NOMA provides the Quality of Service (QoS) to the multi-users by considering the power allocation and data rate factors. Here is considered the outage probability will be 1 when it identifies the different user and allocates the data rate and power.
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Authors and Affiliations

Suprith P. G
1
Mohammed Riyaz Ahmed
2

  1. REVA University, Bangalore, and Karnataka, India
  2. School of Multidisciplinary, REVA University, Bangalore, and Karnataka, India
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Abstract

In this paper, the performance of Low-Density Parity-Check (LDPC) codes is improved, which leads to reduce the complexity of hard-decision Bit-Flipping (BF) decoding by utilizing the Artificial Spider Algorithm (ASA). The ASA is used to solve the optimization problem of decoding thresholds. Two decoding thresholds are used to flip multiple bits in each round of iteration to reduce the probability of errors and accelerate decoding convergence speed while improving decoding performance. These errors occur every time the bits are flipped. Then, the BF algorithm with a low-complexity optimizer only requires real number operations before iteration and logical operations in each iteration. The ASA is better than the optimized decoding scheme that uses the Particle Swarm Optimization (PSO) algorithm. The proposed scheme can improve the performance of wireless network applications with good proficiency and results. Simulation results show that the ASAbased algorithm for solving highly nonlinear unconstrained problems exhibits fast decoding convergence speed and excellent decoding performance. Thus, it is suitable for applications in broadband wireless networks.
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Authors and Affiliations

Ali Jasim Ghaffoori
1
Wameedh Riyadh Abdul-Adheem
1

  1. Department of Electrical Power Techniques Engineering, AL_Ma’moon University College, Baghdad, Iraq
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Abstract

This paper investigates the differential binary modulation for decode-and-forward (DF) based relay-assisted free space optical (FSO) network under the effect of strong atmospheric turbulence together with misalignment error (ME). The atmospheric fading links experience K-distributed turbulence. First we derive novel closed form expression for average bit error rate (BER) and outage probability (OP) in terms of Meijer’s G function. Further, the OP of differential DF-FSO system with multiple relays is derived. We also analyze the asymptotic performance for the sake of getting the order of diversity and the coding gain. The power allotment term is utilized to examine the effect of different power allotment techniques on BER and OP. The simulation results have been used to validate the derived analytical results.
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Authors and Affiliations

Deepti Agarwal
1
Poonam Yadav
2

  1. Department of ECE, Delhi Technical Campus, Greater Noida, U.P, India
  2. Department of ECE, M.G.M College of Engineering and Technology, Noida, U.P, India
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Abstract

The design of a low complexity multiplier-less narrow transition band filter bank for the channelizer of multistandard software-defined radio (SDR) is investigated in this paper. To accomplish this, the modal filter and complementary filter in the upper and lower branches of the conventional Frequency Response Masking (FRM) architecture are replaced with two power-complementary and linear phase filter banks. Secondly, a new masking strategy is proposed to fully exploit the potential of the numerous spectra replicas produced by the interpolation of the modal filter, which was previously ignored in the existing FRM design. In this scheme, the two masking filters are appropriately modulated and alternately masked over the spectra replicas from 0 to 2π, to generate even and odd channels. This Alternate Masking Scheme (AMS) increases the potency of the Modified FRM (ModFRM) architecture for the design of computationally efficient narrow transition band uniform filter bank (termed as ModFRM-FB). Finally, by combining the adjoining ModFRM-FB channels, Non-Uniform ModFRMFB (NUModFRM-FB) for extracting different communication standards in the SDR channelizer is created. To reduce the total power consumption of the architecture, the coefficients of the proposed system are made multiplier-less using Matching Pursuits Generalized Bit-Planes (MPGBP) algorithm. In this method, filter coefficients are successively approximated using a dictionary of vectors to give a sum-of-power-of-two (SOPOT) representation. In comparison to all other general optimization techniques, such as genetic algorithms, the suggested design method stands out for its ease of implementation, requiring no sophisticated optimization or exhaustive search schemes. Another notable feature of the suggested approach is that, in comparison to existing methods, the design time for approximation has been greatly reduced. To further bring down the complexity, adders are reused in recurrent SOPOT terms using the Common Subexpression Elimination (CSE) technique without compromising the filter performance.
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Authors and Affiliations

A.K. Parvathi
1
V. Sakthivel
1

  1. National Institute of Technology, Calicut, India

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