scholarly journals On the modification of bit-flipping decoder of LDPC-codes

2021 ◽  
Vol 21 (1) ◽  
pp. 96-104
Author(s):  
S. S. Gurskiy ◽  
N. S. Mogilevskaya
Keyword(s):  
Error Rate ◽  
Simulation Modeling ◽  
Error Control ◽  
Digital Communication ◽  
Input Parameter ◽  
Ldpc Codes ◽  
Ldpc Code ◽  
Original Algorithm ◽  
Selection Of

Introduction. In all types of digital communication, error control coding techniques are used. Many digital communication standards, such as Wi-Fi and 5G, use low density parity check (LDPC) codes. These codes are popular because they provide building encoders and decoders with low computational complexity. This work objective is to increase the error correcting capability of the well-known bit-flipping decoder (BF) of LDPC-codes. For this purpose, a modification of the decoder is built, which enables to dynamically control one of its main parameters whose choice affects significantly the quality of decoding.Materials and Methods. The well-known bit-flipping decoder of binary LDPC-codes is considered. This decoder has several parameters that are not rigidly bound with the code parameters. The dependence of the decoding quality on the selection of the output parameters of the bit-flipping decoder was investigated through simulation modeling. It is shown that the decoding results in this case are significantly affected by the input parameter of the decoder — threshold T. A modification of the BF-decoder of binary LDPC-codes has been developed, in which it is proposed to set the threshold dynamically during the execution of the algorithm depending on the error rate. A comparative analysis of the error- correcting capability of decoders is carried out by the simulation modeling method.Results. A lemma on the maximum value of the decoder threshold T is formulated and proved. Upper bounds for the number of operations are found for the original and modified decoders. A simulation model that implements a digital noise-immune communication channel has been built. In the model, the initial data is encoded with a given LDPC-code, then it is made noisy by additive uniformly distributed errors, and thereafter, it is decoded in turn by the bit-flipping algorithm with different threshold T parameters, as well as by a modified decoder. Based on the input and output data, the correction capacity of the decoders used is estimated. Experiments have shown that the error-correcting capability of the modified decoder in the range of the real error rate is higher than that of the original decoder, regardless of the selection of its parameters.Discussion and Conclusions. The lemma, proved in the paper, sets the upper bound on the threshold value in the original decoder, which simplifies its adjustment. The developed modification of the decoder has a better error- correcting capability compared to the original decoder. Nevertheless, the complexity of the modification is slightly increased compared to the original algorithm. It has been pointed out that the decoding quality of a modified decoder develops with a decrease in the number of cycles in the Tanner graph and an increase in the length of the code.Keywords: LDPC-codes, error-correcting capability, dynamic threshold, binary symmetric channel, experimental research.

Research on Clustering Analysis Based on SOM

2013 ◽  
Vol 475-476 ◽  
pp. 968-971
Author(s):  
Hai Xue Liu ◽  
Rui Jun Yang ◽  
Wen Ju Li ◽  
Wan Jun Yu ◽  
Wei Lu
Keyword(s):  
Clustering Analysis ◽  
Clustering Algorithm ◽  
Poor Quality ◽  
Original Algorithm ◽  
Space Model ◽  
Som Algorithm ◽  
Som Network ◽  
Som Clustering ◽  
Selection Of

In this paper, we present an improved text clustering algorithm. It not only maintains the self-organizing features of SOM network, but also makes up the disadvantages of the bad clustering effect caused by the inadequate selection of K-means algorithm. Firstly, data is preprocessed to form vector space model for subsequent process. Then, we analyze the features of original clustering algorithm and SOM algorithm, and plan an improved SOM clustering algorithm to overcome low stability and poor quality of original algorithm. The experimental results indicate that the improved algorithm has a higher accuracy and has a better stability, compared with the original algorithm.

Error Correction Based on LDPC Codes in Wireless Optical Communication

2013 ◽  
Vol 380-384 ◽  
pp. 3811-3814
Author(s):  
Xiao Rong Gao ◽  
Pei Wang ◽  
Jian Qiang Guo ◽  
Jin Long Li ◽  
Kai Yang ◽  
...  
Keyword(s):  
Error Correction ◽  
Optical Communication ◽  
Error Rate ◽  
Error Control ◽  
Channel Model ◽  
Ldpc Codes ◽  
Atmospheric Environment ◽  
Atmospheric Scattering ◽  
Wireless Optical Communication ◽  
Beam Expander

Complex atmospheric environment seriously affect the quality of wireless of information transmission. In order to improve the wireless optical communication quality, and reduce the influence of attenuation, flicker, angle misalignment caused by atmospheric scattering, absorption, turbulence, beam expander, mismatch, atmospheric channel model is established while coding techniques for error control in wireless optical communication was researched into.The improvement result of error rate by error correction coding in different SNR situations was obtained. The results showed that the LDPC coding can significantly reduce the BER. For Gaussian channel, SNR can be reduced 8 dB when BER is 10-6; For wireless optical communication , LDPC codes can make the error rate reduced by 4-5 orders of magnitude.

scholarly journals A Simplified Model of Bit Error Rate Calculation

2015 ◽  
Vol 9 (1) ◽  
pp. 41
Author(s):  
Saed Ali Thuneibat ◽  
Huthaifa Al_Issa ◽  
Abdallah Ijjeh
Keyword(s):  
Bit Error Rate ◽  
Error Rate ◽  
Communication Systems ◽  
Digital Communication ◽  
Computing Time ◽  
Proposed Model ◽  
Rate Calculation ◽  
Digital Communication Systems ◽  
Key Parameter

<p>The Bit Error Rate (BER) is a key parameter of the Quality of Service (QoS) for engineers and designers of digital communication systems and networks. At the present  time, a set of models and methods are exist for calculating the BER. But these methods are complex and require large computing cost.</p><p>In this paper, we provide a new model for calculating the BER. This model simplifies the procedures in the existing models and reduces the computing time. In the same time, the proposed model save the accuracy and the state consideration of existing models.</p>

ON THE EXPERT’S RIGHT TO BE PRESENT AT LEGAL PROCEEDINGS

2016 ◽  
Vol 15 ◽  
pp. 163-171
Author(s):  
M. G. Shcherbakovskiy
Keyword(s):  
Initial Data ◽  
Legal Proceedings ◽  
Reliable Assessment ◽  
Data Acquiring ◽  
Selection Of

The article discusses the reasonsfor an expert to participate in legal proceedings. The gnoseological reason for that consists of the bad quality of materials subject to examination that renders the examination either completely impossible or compromises objective, reasoned and reliable assessment of the findings. The procedural reason consists ofa proscription for an expert to collect evidence himself or herself. The author investigates into the ways of how an expert can participate in legal proceedings. If the defense invites an expert to participate in the proceedings, then it is recommended that his or her involvement should be in the presence of attesting witnesses and recorded in the protocol. In the course of the legal proceedings an expert has the following tasks: adding initial data, acquiring new initial data, understanding the situation of the incident, acquiring new objects to be studied, including samples for examination. An expert’s participation in legal proceedings differs from the participation of a specialist or an examination on the scene of the incident. The author describes the tasks that an expert solves in the course of legal proceedings, the peculiarities ofan investigation experiment practices, the selection of samples for an examination, inspection, interrogation.

Pengaruh Kualitas Pelayanan Terhadap Kepuasan Pelanggan di Kantor Perusahaan Umum Badan Urusan Logistik Kota Sampit Kabupaten Kotawaringin Timur

2016 ◽  
Vol 2 (2) ◽  
pp. 1-5
Author(s):  
Masrukin Masrukin ◽  
Hermanto Hermanto
Keyword(s):  
Quality Of Service ◽  
Customer Satisfaction ◽  
Service Quality ◽  
Error Rate ◽  
Research Method ◽  
Statistical Test ◽  
Quality Factors ◽  
Public Companies ◽  
Public Company

Customer satisfaction is influenced by service quality factors, this study aims to find out and analyze how much influence the quality of service on customer satisfaction is felt by customers who use the service of Poor Rice (Raskin) at the Office of Public Companies Logistics Agency (Perum BULOG) in Sampit City Regency East Kotawaringin. The research method used in this study is the method of observation, questionnaire/questionnaire and documentation using a Likert scale and the method of determining the sample used is the error rate of 5% as many as 213 samples. Testing the hypothesis used is a statistical test with the formula "Product moment person". The results showed that there was a very strong correlation between Service Quality and Customer Satisfaction of the Office of Public Company of the Logistics Affairs Agency (Perum BULOG) in the District of East Kotawaringin. As much as 0.9968514278 based on the calculation of Pearson Product Moment value.

Implementasi Voip Server Berbasis IPV6 Dengan Raspberry PI

2019 ◽  
Vol 9 (01) ◽  
pp. 47-54
Author(s):  
Rabbai San Arif ◽  
Yuli Fitrisia ◽  
Agus Urip Ari Wibowo
Keyword(s):  
Internet Protocol ◽  
Wireless Transmission ◽  
Raspberry Pi ◽  
Test Results ◽  
Average Delay ◽  
Ipv6 Network ◽  
Ip Network ◽  
Selection Of ◽  
Better Than

Voice over Internet Protocol (VoIP) is a telecommunications technology that is able to pass the communication service in Internet Protocol networks so as to allow communicating between users in an IP network. However VoIP technology still has weakness in the Quality of Service (QoS). VOPI weaknesses is affected by the selection of the physical servers used. In this research, VoIP is configured on Linux operating system with Asterisk as VoIP application server and integrated on a Raspberry Pi by using wired and wireless network as the transmission medium. Because of depletion of IPv4 capacity that can be used on the network, it needs to be applied to VoIP system using the IPv6 network protocol with supports devices. The test results by using a wired transmission medium that has obtained are the average delay is 117.851 ms, jitter is 5.796 ms, packet loss is 0.38%, throughput is 962.861 kbps, 8.33% of CPU usage and 59.33% of memory usage. The analysis shows that the wired transmission media is better than the wireless transmission media and wireless-wired.

DESIGN, SIMULATION AND IMPLEMENTATION MONITORING SYSTEM FOR SYSTEM CONTROL C4 FEEDING PUMP FOR FEED VAPORIZATION IN THE BUTADIENE PLANT

2020 ◽  
Vol 1 (1) ◽  
pp. 31-35
Author(s):  
Fahmi Yunistyawan ◽  
Yunistyawan J Berchmans ◽  
Gembong Baskoro
Keyword(s):  
Motor Control ◽  
Control System ◽  
Field Operator ◽  
System Control ◽  
Variable Speed ◽  
Variable Speed Drive ◽  
Software And Hardware ◽  
Discharge Pressure ◽  
Selection Of

This study implements the auto start control system on an electric motor 3 phase C4Feeding pump when the discharge pressure is low-low (4.3 kg /cm²). The C4 feeding pumpmotor was initially manually operated from the local control station, this was very ineffectiveand inefficient because it still relied on the field operator to operate the pump motor and whenthe plant was in normal operating it is very risk if the field operator late to operate motor then itwill impact to quality of the product, and if the delay time to operate motor is too long then planthave to shut down, therefore improvement is needed in the C4 feeding pump motor controlsystem. In this paper, various types of 3-phase motor control are explained which allow it to beapplied to the C4 feeding pump motor that are on-off, inverter, and variable speed drive andefficient selection of the three systems control of the motor. Software and hardware used in thisthesis work are DCS CENTUM VP Yokogawa.

Thomas More’s Correspondence in a Spanish Ambiance

Moreana ◽  
2002 ◽  
Vol 39 (Number 149) (1) ◽  
pp. 41-60 ◽  
Author(s):  
Eugenio M. Olivares Merino
Keyword(s):  
The Subject ◽  
Selection Of

The recent reprinting of Álvaro de Silva’s 1998 edition of a selection of More’s letters prompts the author to examine the subject of Spanish translations of More, and of de Silva’s general commentary on More’s correspondence and on his relationship to other humanists. The author reflects on aspects of More’s personality as exposed in his letters and uses what he finds as a corrective to several biographical misconceptions. He points out the strengths and weaknesses of de Silva’s work and compares it with that of other translators, particularly Elizabeth Rogers, and notes the particularly Spanish quality of de Silva’s edition.

COMBINATORIAL POLYNOMIALLY COMPUTABLE CHARACTERISTICS OF SUBSTITUTIONS AND THEIR PROPERTIES

2020 ◽  
Vol 7 (2) ◽  
pp. 34-41
Author(s):  
VLADIMIR NIKONOV ◽  
◽  
ANTON ZOBOV ◽  
Keyword(s):  
Mathematical Expectation ◽  
Point Of View ◽  
Small Range ◽  
Computational Point ◽  
Wide Range ◽  
Bijective Function ◽  
The Difference ◽  
Element Base ◽  
Selection Of

The construction and selection of a suitable bijective function, that is, substitution, is now becoming an important applied task, particularly for building block encryption systems. Many articles have suggested using different approaches to determining the quality of substitution, but most of them are highly computationally complex. The solution of this problem will significantly expand the range of methods for constructing and analyzing scheme in information protection systems. The purpose of research is to find easily measurable characteristics of substitutions, allowing to evaluate their quality, and also measures of the proximity of a particular substitutions to a random one, or its distance from it. For this purpose, several characteristics were proposed in this work: difference and polynomial, and their mathematical expectation was found, as well as variance for the difference characteristic. This allows us to make a conclusion about its quality by comparing the result of calculating the characteristic for a particular substitution with the calculated mathematical expectation. From a computational point of view, the thesises of the article are of exceptional interest due to the simplicity of the algorithm for quantifying the quality of bijective function substitutions. By its nature, the operation of calculating the difference characteristic carries out a simple summation of integer terms in a fixed and small range. Such an operation, both in the modern and in the prospective element base, is embedded in the logic of a wide range of functional elements, especially when implementing computational actions in the optical range, or on other carriers related to the field of nanotechnology.

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