scholarly journals Complete MDP convolutional codes

2019 ◽  
Vol 18 (06) ◽  
pp. 1950105 ◽  
Author(s):  
Julia Lieb
Keyword(s):  
Waiting Time ◽  
Recovery Rate ◽  
Convolutional Codes ◽  
Optimal Recovery ◽  
Base Field ◽  
Concrete Construction ◽  
Additional Advantage ◽  
Decoding Algorithms ◽  
Construction Techniques ◽  
Maximum Distance Profile

Maximum distance profile (MDP) convolutional codes have the property that their column distances are as large as possible. It has been shown that, transmitting over an erasure channel, these codes have optimal recovery rate for windows of a certain length. Reverse MDP convolutional codes have the additional advantage that they are suitable for forward and backward decoding algorithms. Beyond that the subclass of complete MDP convolutional codes has the ability to reduce the waiting time during decoding. The first main result of this paper is to show the existence and genericity of [Formula: see text] complete MDP convolutional codes for all code parameters with [Formula: see text] as well as that complete MDP convolutional codes cannot exist if [Formula: see text]. The second main contribution is the presentation of two concrete construction techniques to obtain complete MDP convolutional codes. These constructions work for all code parameters with [Formula: see text] but require that the size of the underlying base field is (sufficiently) large.

On the existence and construction of maximum distance profile convolutional codes

2021 ◽  
Vol 75 ◽  
pp. 101877
Author(s):  
Ángel Luis Muñoz Castañeda ◽  
Francisco J. Plaza-Martín
Keyword(s):  
Convolutional Codes ◽  
Maximum Distance ◽  
Maximum Distance Profile

Study on Ultimate Recovery Factor and Oil Recovery Rate of Water-Flooded Sandstone Oil Fields in Eastern South China Sea

2021 ◽  
Author(s):  
Qi Xiong ◽  
Zhenghe Yan ◽  
Li Li ◽  
Yong Yang ◽  
Yahui Wang ◽  
...  
Keyword(s):  
South China Sea ◽  
South China ◽  
Oil Recovery ◽  
Recovery Rate ◽  
Optimal Recovery ◽  
Oil Fields ◽  
Displacement Efficiency ◽  
China Sea ◽  
Oil Displacement ◽  
Oil Displacement Efficiency

Abstract Under the natural energy development of Marine sandstone oil fields in the east of the South China Sea, the recovery degree of some oil fields has exceeded 65%, and the production capacity is still strong. The high-speed development model does not seem to have an adverse effect on oil recovery. Based on the existing knowledge and technical conditions, it is difficult to analyze and predict the final recovery rate of oil field. The reasonable boundary between the oil rate and recovery is also unclear. In this study, we investigate the correlation between oil rate and recovery rate by experiment and field practice. Based on the microscopic displacement experiment, the variation rules of phase permeability, wettability, residual oil, displacement efficiency and sweep volume of different displacement multiples are studied. The variation law of oil rate and recovery under different fluidity and well control conditions is studied by mathematical statistics according to the production dynamic data. Thus, the influencing factors and percolation mechanism of the optimal recovery under high multiples water flooding are clarified, and the relationship between the reasonable oil rate and optimal recovery under different reservoir conditions is formed. Micro experiments show that high multiples water flooding can improve the reservoir property, change wettability of rocks, reduce the residual oil saturation, improve oil displacement efficiency and the final oil displacement efficiency can reach 80%. Statistical research shows that when the oil recovery rate is less than 10%, the recovery rate increases with the increase of oil rate. For bottom water reservoirs, the recovery rate is recommended to be no more than 8%. The paper innovatively studies the correlation between the reasonable oil rate and optimal recovery in Marine sandstone oilfield from microscopic experimental analysis and macroscopic statistical research. The research results effectively guide the oil field production practice of more than 200 Wells in more than 20 oil fields in the eastern South China Sea in 2019, with a cumulative oil increase of more than 5 million barrels. And it has important guiding significance to the efficient and economical development of Marine sandstone oilfield.

scholarly journals Optimization–based decoding algorithms for LDPC convolutional codes in communication systems

2019 ◽  
Vol 51 (10) ◽  
pp. 1061-1074
Author(s):  
Banu Kabakulak ◽  
Z. Caner Taşkın ◽  
Ali Emre Pusane
Keyword(s):  
Communication Systems ◽  
Convolutional Codes ◽  
Decoding Algorithms

scholarly journals Erasure decoding of convolutional codes using first-order representations

2021 ◽  
Author(s):  
Julia Lieb ◽  
Joachim Rosenthal
Keyword(s):  
Linear Systems ◽  
Convolutional Code ◽  
Recovery Process ◽  
Convolutional Codes ◽  
Computational Effort ◽  
Decoding Algorithms ◽  
Additional Information ◽  
Time Linear ◽  
Natural Way ◽  
Space Description

AbstractIt is well known that there is a correspondence between convolutional codes and discrete-time linear systems over finite fields. In this paper, we employ the linear systems representation of a convolutional code to develop a decoding algorithm for convolutional codes over the erasure channel. In this kind of channel, which is important due to its use for data transmission over the Internet, the receiver knows if a received symbol is correct. We study the decoding problem using the state space description of a convolutional code, and this provides in a natural way additional information. With respect to previously known decoding algorithms, our new algorithm has the advantage that it is able to reduce the decoding delay as well as the computational effort in the erasure recovery process. We describe which properties a convolutional code should have in order to obtain a good decoding performance and illustrate it with an example.

scholarly journals On the left primeness of some polynomial matrices with applications to convolutional codes

2020 ◽  
pp. 2150207
Author(s):  
Gianira N. Alfarano ◽  
Julia Lieb
Keyword(s):  
Polynomial Matrix ◽  
Convolutional Code ◽  
Convolutional Codes ◽  
Maximum Distance ◽  
Parity Check ◽  
Parity Check Matrix ◽  
Polynomial Matrices ◽  
Check Matrix ◽  
Maximum Distance Profile

Maximum distance profile (MDP) convolutional codes have the property that their column distances are as large as possible for given rate and degree. There exists a well-known criterion to check whether a code is MDP using the generator or the parity-check matrix of the code. In this paper, we show that under the assumption that [Formula: see text] divides [Formula: see text] or [Formula: see text] divides [Formula: see text], a polynomial matrix that fulfills the MDP criterion is actually always left prime. In particular, when [Formula: see text] divides [Formula: see text], this implies that each MDP convolutional code is noncatastrophic. Moreover, when [Formula: see text] and [Formula: see text] do not divide [Formula: see text], we show that the MDP criterion is in general not enough to ensure left primeness. In this case, with one more assumption, we still can guarantee the result.

scholarly journals Analysis of Winter Concrete Construction in Water Conservation Project

2018 ◽  
Vol 2 (3) ◽  
Author(s):  
Wenzhong Sun
Keyword(s):  
Low Temperature ◽  
Water Conservation ◽  
Northern China ◽  
Control Measures ◽  
Atmospheric Conditions ◽  
Concrete Construction ◽  
Flood Season ◽  
Construction Techniques ◽  
Flood Period ◽  
Water Conservancy

The construction of water conservancy projects should commence during optimal atmospheric conditions and non-flood period to ensure completion before the flood season begin in summer. In most areas of Northern China, the temperature during winter remain at lower level, in which environmental factors play the most important role in the construction of water conservancy projects. In particular, low temperature directly affects the strength of concrete and delays its solidification, this highly affects the quality and progress of concrete construction. In order to overcome this barrier, better planning, for reasonable and effective construction techniques and targeted control measures should be adopted to reduce the adverse effects of low temperature to assure a strong and safe architecture.

scholarly journals Convolutional codes with maximum distance profile

2005 ◽  
Vol 54 (1) ◽  
pp. 53-63 ◽  
Author(s):  
Ryan Hutchinson ◽  
Joachim Rosenthal ◽  
Roxana Smarandache
Keyword(s):  
Convolutional Codes ◽  
Maximum Distance ◽  
Maximum Distance Profile

Comparison of Aerobic and Anaerobic Incubation Conditions for Optimal Recovery of Salmonella

1984 ◽  
Vol 47 (8) ◽  
pp. 615-617 ◽  
Author(s):  
J. S. BAILEY ◽  
J. O. REAGAN ◽  
N. A. COX ◽  
J. E. THOMSON
Keyword(s):  
Recovery Rate ◽  
Optimal Recovery ◽  
Mixed Cultures ◽  
Anaerobic Incubation ◽  
Aerobic Incubation ◽  
Enrichment Broth ◽  
Pure Cultures ◽  
Selective Plating ◽  
Aerobic And Anaerobic ◽  
Feed Samples

Effects of aerobic and anaerobic incubation of selenite-cystine and TT enrichment broth incubated at 37 and 34°C on the growth of Salmonella were determined. Pure cultures of four serotypes of Salmonella were enumerated at 0, 4, 8 and 24 h of incubation and no significant differences related to incubation conditions were found. The effect of microflora other than Salmonella, in pure and mixed cultures and from chicken and feed samples, on the recovery rate of Salmonella after incubation in enrichment media was evaluated and no significant effects were found; however, aerobic incubation usually gave higher Salmonella counts. Greater recovery of Salmonella was obtained by incubating selective plating media aerobically rather than anaerobically. Aerobic incubation of liquid enrichment media and differential plating media is therefore recommended for optimal recovery of Salmonella.

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