A proof of maximum contention-free property of interleavers for Turbo codes using permutation polynomials over integer rings

It is well known that interleavers play a critical role in Turbo coding/decoding schemes, and contention-free interleaver design has become a serious problem in the paraUelization of Turbo decoding, which is indispensable to meet the demands for high throughput and low latency in next generation mobile communication systems. This paper unveils the fact that interleavers based on permutation polynomials modulo N are contention-free for every window size W, a factor of the intedeaver length N, which, also called maximum contention-free interleavers.

Application of Rollout Strategy to Test Points Selection for Integer-Coded Fault Wise Table

Test points selection for integer-coded fault wise table is a discrete optimization problem. The global minimum set of test points can only be guaranteed by an exhaustive search which is eompurationally expensive. In this paper, this problem is formulated as a heuristic depth-first graph search problem at first. The graph node expanding method and rules are given. Then, rollout strategies are applied, which can be combined with the heuristic graph search algorithms, in a computationally more efficient manner than the optimal strategies, to obtain solutions superior to those using the greedy heuristic algorithms. The proposed rollout-based test points selection algorithm is illustrated and tested using an analog circuit and a set of simulated integer-coded fault wise tables. Computa- tional results are shown, which suggest that the rollout strategy policies are significantly better than other strategies.

Selection of Minimal Test Points Set for Integer-Coded Fault Wise Table

Test points selection for integer-coded fault wise table is a discrete optimization problem. On one hand, traditional exhaustive search method is computationally expensive. On the other hand, the space complexity of traditional exhaustive is low. A tradeoff method between the high time complexity and low space complexity is proposed. At first, a new fault-pair table is constructed based on the integer-coded fault wise table. The fault-pair table consists of two columns： one column represents fault pair and the other represents test points set that can distinguish the corresponding faults. Then, the rows are arranged in ascending order according to the cardinality of corresponding test points set. Thirdly, test points in the top rows are selected one by one until all fault pair are isolated. During the test points selection process, the rows that contain selected test points are deleted and then the dimension of fault-pair table decreases gradually. The proposed test points selection algorithm is illustrated and tested using an integercoded fault wise table derived from a real analog circuit. Computational results suggest show policies are better than the exhaustive strategy.

An Integer Coding Based Optimization Model for Queen Problems

Queen problems are unstructured problems, whose solution scheme can be applied in the actual job scheduling. As for the n-queen problem, backtracking algorithm is considered as an effective approach when the value of n is small. However, in case the value of n is large, the phenomenon of combination explosion is expected to occur. In order to solve the aforementioned problem, queen problems are firstly converted into the problem of function optimization with constraints, and then the corresponding mathematical model is established. Afterwards, the n-queen problem is solved by constructing the genetic operators and adaption functions using the integer coding based on the population search technology of the evolutionary computation. The experimental results demonstrate that the proposed algorithm is endowed with rapid calculation speed and high efficiency, and the model presents simple structure and is readily implemented.

A Novel Decoding Method for Non-Binary TCM Codes

A new non-binary decoding method, which is called Yaletharatalhussein decoding algorithm, is designed and implemented for decoding non-binary convolutional codes which is based on the trellis diagram representing the convolutional encoder. Yaletharatalhussein decoding algorithm outperforms the Viterbi algorithm and other algorithms in its simplicity, very small computational complexity, decoding reliability for high states TCM codes that suitable for Fourth-Generation (4G), decreasing errors with increasing word length, and easy to implement with real-time applications. The proposed Yaletharatalhussein decoding algorithm deals with non-binary error control coding of the convolutional and TCM codes. Convolutional codes differ from block codes in that a block code takes a fixed message length and encodes it, whereas a convolutional code can encode a continuous stream of data, and a hard-decision decoding can easily be realized using the Yaletharatalhussein algorithm. The idea of non-binary codes has been extended for symbols defined over rings of integers, which outperform binary codes with only a small increase in decoding complexity. The simulation results show that the performance of the nonbinary TCM-based Yaletharatalhussein algorithm outperforms the binary and non-binary decoding methods.

室内多消防水炮协同灭火任务规划研究

室内大空间消防系统通常采用多个固定式智能消防水炮组成水炮群进行灭火。为改善室内多消防水炮对多火源灭火效率,提出一种基于火灾损失代价和灭火时间代价的粒子群任务规划算法。首先,采用整数编码方式对粒子进行编码,一组编码对应一组任务分配解;然后,应用非线性自适应权重更新方法动态调整算法关键参数,提升算法性能。为避免陷入局部最优解,采用基于模拟退火的自适应粒子群算法,以一定概率接受差解,提高粒子多样性,帮助算法跳出局部最优。针对火源动态变化和灭火过程中新发火源,设计了一种分阶段任务规划策略,与所提算法结合可有效解决动态规划问题。实例仿真结果表明,该算法在寻优效率和结果稳定性方面优于标准粒子群算法和自适应粒子群算法,具有良好的应用价值。

Buffer Overflow Detection on Binary Code

Most solutions for detecting buffer overflow are based on source code. But the requirement tor source code is not always practical especially for business software. A new approach was presented to detect statically the potential buffer overflow vulnerabilities in the binary code of software. The binary code was translated into assembly code without the lose of the information of string operation functions. The feature code abstract graph was constructed to generate more accurate constraint statements, and analyze the assembly code using the method of integer range constraint. After getting the elementary report on suspicious code where buffer overflows possibly happen, the control flow sensitive analysis using program dependence graph was done to decrease the rate of false positive. A prototype was implemented which demonstrates the feasibility and efficiency of the new approach.

Second Generation Wavelet Applied to Lossless Compression Coding of Image

In this paper, the second generation wavelet transform is applied to image lossless coding, according to its characteristic of reversible integer wavelet transform. The second generation wavelet transform can provide higher compression ratio than Huffman coding while it reconstructs image without loss compared with the first generation wavelet transform. The experimental results show that the se cond generation wavelet transform can obtain excellent performance in medical image compression coding.

A High Spectral Efficient Non-Binary TCM Scheme-Based Novel Decoding Algorithm for 4G Systems

This paper deals with the MIMO-OFDM technique that is applied to the fourth generation (4G) of the wireless communication systems, this technique can provide high data rate transmission without increasing transmit power and expanding bandwidth, it can also efficiently use space resources and has a bright future. It presents the channel coding assisted STBC-OFDM systems, and employs the Coded Modulation techniques (CM), since the signal bandwidth available for wireless communications is limited. The proposed system deals with Non-binary error control coding of the TCM-aided STBC-OFDM scheme for transmissions over the Rayleigh channel. A new non-binary decoding method, Yaletharatalhussein decoding algorithm, is designed and implemented for decoding non-binary convolutional codes, which is based on the trellis diagram representing the convolutional encoder. Yaletharatalhussein decoding algorithm outperforms the Viterbi algorithm and other algorithms in its simplicity, very small computational complexity, decoding reliability for high states TCM codes that are suitable for Fourth-Generation (4G), decreasing errors with increasing word length, and easy to implement with real-time applications. The simulation results show that the performance of the non-binary TCM-based Yaletharatalhussein decoding algorithm-assisted STBC-OFDM scheme outperforms the binary and non-binary decoding methods.

An Optimal Algorithm for Prufer Codes

This paper studies the algorithms for coding and decoding Prufer codes of a labeled tree. The algorithms for coding and decoding Prufer codes of a labeled tree in the literatures require time usually. Although there exist linear time algorithms for Prufer-like codes [1,2,3], the algorithms utilize the integer sorting algorithms. The special range of the integers to be sorted is utilized to obtain a linear time integer sorting algorithm. The Prufer code problem is reduced to integer sorting. In this paper we consider the Prufer code problem in a different angle and a more direct manner. We start from a naïve algorithm, then improved it gradually and finally we obtain a very practical linear time algorithm. The techniques we used in this paper are of interest in their own right.

考虑风光的两阶段配电网动态重构方法

由于传统的控制手段已不能抵抗高渗透率分布式电源对电网的冲击,需要对含分布式电源的配电网动态重构问题展开研究。针对传统配网重构中考虑分布式电源不足、过程复杂耗时和实用性较低等问题,提出了基于生物地理学算法的含分布式电源配电网动态重构两阶段优化策略,建立了以全时段网损最小和开关操作总次数最少为目标的多目标优化模型。首先运用整数型环网编码方法以降低变量维数,对配电网进行时段初步划分,运用夹逼策略对优化区间进行“列举”操作,得到初步优化方案。在此基础上,考虑开关操作总次数约束,对其进行时段的二次优化,最终确定动态重构的开关动作时刻及组合。通过算例验证了该动态重构方法能够在保证操作次数较低的同时,达到减少配电网有功损耗、提高节点电压稳定性的目的。

艾森斯坦整数优化的SCMA码本设计方法

第五代移动通信(5G)技术具有极高的数据传输速率并支持海量数据连接,然而传统的正交接入技术无法保证资源的高效利用。稀疏码分多址接入(SCMA)技术是一种非正交多址技术,通过资源块的有效分配保证了海量用户信息的可靠传输。在SCMA技术中,码本起着至关重要的作用。为了解决传统码本设计方法存在的误码率降低受限问题,通过艾森斯坦整数对资源块上的母星座进行构造,并引入网格编码调制技术(TCM)的子集分割思想,从而提出一种艾森斯坦整数优化(EIO)码本设计方法。仿真结果表明,在相同条件下,相比华为码本、传统艾森斯坦整数码本及TCM码本,EIO码本可以达到更低的误码率,为SCMA技术提供了一个可行的码本设计方法。

基于改进多维粒子群的多无人机任务分配方法

针对复杂战场环境下的多无人机任务规划解空间维度不确定、任务需求随时间变化等问题,提出了一种基于改进多维粒子群算法的多无人机任务分配方法。该方法构建了适应度函数集,应用多个适应度函数来限制种群趋向,同时采用基于时变目标价值的映射变量,建立目标价值随时间变化的多无人机目标决策模型;而后引入整数编码机制,构建面向任务序列的多维粒子,利用改进的自适应多维粒子群算法,得到最优维度下多无人机的任务分配优化方案。仿真实验结果表明:基于改进多维粒子群算法的多无人机任务规划方法可在最优解空间下,获得更好的任务动态分配效果,收敛速度更快,具有良好的推广应用前景。

接入光伏、风电的上海中原地区配电网重构研究

分布式电源的接入,对配电网的安全运行产生影响。文中基于配电网简化模型和分布式电源出力模型,建立了接入光伏、风电的配电网多目标实时重构模型。该模型在系统重构间隔内,选取系统网损、电压质量和均衡负荷为综合目标,考虑光伏、风电接入的运行安全为约束,采用整数型分区编码和无效解判断策略,大幅降低了变量维数。对上海中原地区的配电网进行分析,得到了各时段的重构方案,验证了所提方法的可行性和有效性。

A reversibility-gain model for integer Karhunen-Loève transform design in video coding

Karhunen-Loeve transform （KLT） is the optimal transform that minimizes distortion at a given bit allocation for Gaussian source. As a KLT matrix usually contains non-integers, integer-KLT design is a classical problem. In this paper, a joint reversibility-gain （R-G） model is proposed for integer-KLT design in video coding. Specifically, the ＇reversibility＇ is modeled according to distortion analysis in using forward and inverse integer transform without quantization. It not only measures how invcrtible a transform is, but also bounds the distortion introduced by the non-orthonormal integer transform process. The ＇gain＇ means transform coding gain （TCG）, which is a widely used criterion for transform design in video coding. Since KLT maximizes the TCG under some assumptions, here we define the TCG loss ratio （LR） to measure how much coding gain an integer-KLT loses when compared with the original KLT. Thus, the R-G model can be explained as follows： subject to a certain TCG LR, an integer- KLT with the best reversibility is the optimal integer transform for a given non-integer-KLT. Experimental results show that the R-G model can guide the design of integer-KLTs with good performance.

Integer Codes Correcting Single Errors and Random Asymmetric Errors within a Byte

In optical networks without optical amplifiers(ONWOAs) photons may fade or fail to be detected, but new photons cannot be generated. Hence, under normal conditions, only 1 → 0 errors can occur. However, in some situations, the photodetector may generate a false 0 → 1 error. This mostly occurs in cases when the dark current is higher than specified. With this in mind, in this paper,the authors present a class of codes suitable for use in ONWOAs using self-synchronous scramblers.The presented codes can correct single errors and random asymmetric(1 → 0) errors within a b-bit byte. Unlike classical codes, these codes use integer and lookup table operations. As a result, their interleaved version, implemented on a dual-core 3.0 GHz processor, achieves the theoretical throughput above the operating rate of 10 G networks.

A spatial multi-scale integer coding method and its application to three-dimensional model organization

With the rapid development of digital earth,smart city,and digital twin technology,the demands of three-dimensional model data’s application is getting higher and higher.These data tend to be multi-objectification,multi-type,multi-scale,complex spatial relationship,and large amount,which brings great challenges to the efficient organization of them.This paper mainly studies the organization of three-dimensional model data,and the main contributions are as follows:1)A integer coding method of three dimensional multi-scale grid is proposed,which can reduce the four-dimensional(spatial dimension and scale dimension)space into one-dimensional,and has better space and scale clustering characteristics by comparing with various types of grid coding.2)The binary algebra calculation method is proposed to realize the basic spatial relationship calculation of three-dimensional grid,which has higher spatial relationship computing ability than 3D-Geohash method;3)The multi-scale integer coding method is applied to the data organization of three-dimensional city model,and the experiment results show that:it is more efficient and stable than the threedimensional R-tree index and Geohash coding method in the establishment of index and the query of three dimensional space.

基于艾森斯坦整数的粒子群优化SCMA码本

稀疏码多址(SCMA)是一种码域的非正交多址(NOMA)方案,可以实现未来的大规模机器型通信网络,而码本的设计对于SCMA系统至关重要。该文在艾森斯坦整数的基础上,按照不同角度将选取的艾森斯坦整数分为三组,在这三组中选择两组艾森斯坦整数作为母星座。根据同一资源块被多个用户占用,且占用的用户的功率之和为定值,随机分配用户的功率从而构造功率不平衡的码本,以最大化最小欧氏距离为目标函数,相关参数作为变量,最后利用粒子群算法求出最优解。通过数值仿真结果表明,与已有的码本相比,该文提出的码本在高斯信道下的误码率(BER)更小,性能更优。

Improved rate-distortion optimized video coding using non-integer bit estimation and multiple Lambda search

Many modern video encoders use the Lagrangian rate-distortion optimization （RDO） algorithm for mode deci- sions during the compression procedure. For each encoding stage, this approach involves minimizing a cost, which is a function of rate, distortion and a multiplier called Lambda. This paper proposes to improve the RDO process by applying two modifications. The first modification is to increase the ac- curacy of rate estimation, which is achieved by computing a non-integer number of bits for arithmetic coding of the syntax elements. This leads to a more accurate cost computation and therefore a better mode decision. The second modification is to search and adjust the value of Lambda based on the char- acteristics of each coding stage. For the encoder used, this paper proposes to search multiple values of Lambda for the intra-4x4 mode decision. Moreover, a simple shift in Lambda value is proposed for motion estimation. Each of these modi- fications offers a certain gain in RDO performance, and, when all are combined, an average bit-rate saving of up to 7.0% can be achieved for the H.264/AVC codec while the same concept is applicable to the H.265/HEVC codec as well. The extra added complexity is contained to a certain level, and is also adjustable according to the processing resources available.

基于Geohash的面数据区域查询

鉴于Geohash编码的全球唯一性、多层次递归性和一维的特性,以及Geohash目前通常只用于邻近点数据的空间查询而鲜用于面数据空间查询的现状,提出了一种基于Geohash的面数据区域查询方案,描述了对面数据和查询区域的处理方法。主要思路是将面数据关联到若干Geohash单元网格,并在数据库中保存网格的Geohash编码与面数据的对应关系,查询时将查询区域根据规则对应到最多4个Geohash编码,再根据编码查询与区域相交的面数据。通过对比试验可知,在数据量较大且查询区域较小的情况下,基于Geohash编码的面数据查询效率较基于经纬度和R-树的查询效率高,在海量空间数据检索上具有一定应用价值。