Edge Coloring of Graphs with Applications in Coding Theory

In this paper,a new type of edge coloring of graphs together with an algorithm for such an edge coloring is presented to construct some columnweight three low-density parity-check(LDPC)codes whose Tanner graphs are free of 4-cycles.This kind of edge coloring is applied on some well-known classes of graphs such as complete graphs and complete bipartite graphs to generate some column-weight 3 LDPC codes having flexibility in terms of code length and rate.Interestingly,the constructed(3;k)-regular codes with regularities k=4;5;:::;22 have lengths n=12;20;26,35;48;57;70;88;104;117;140;155;176;204;228;247;280;301;330;having minimum block length compared to the best known similar codes in the literature.In addition to linear complexity of generating such parity-check matrices,they can be considered as the base matrices of some quasi-cyclic(QC)LDPC codes with maximum achievable girth 18,which inherit the low-complexity encoder implementations of QC-LDPC codes.Simulation results show that the QC-LDPC codes with large girth lifted from the constructed base matrices have good performances and outperform random codes,progressive edge growth LDPC codes,some finite fields and group rings based QC-LDPC codes and also have a close competition to the standard IEEE 802.16e(WiMAX)code.

Some Explicit Constructions of Type-Ⅱ,Ⅲ,Ⅳ,Ⅴ QC-LDPC Codes with Girth 6

Multi-type quasi-cyclic(QC) low-density parity-check(LDPC) codes can be considered as multiple-edge protograph QC-LDPC codes having some advantages in the minimum Hamming distance bound over single-edge protograph codes or type-Ⅰ QC-LDPC codes when the base matrices have the same size. In this paper, we investigate a class of multi-type QC-LDPC codes whose parity-check matrices contain just one blockrow of circulants and we obtain the generator matrix of such codes in general form. Using the permutation arrays and defining injection arrays, we present a new approach to construct a class of high-rate type-Ⅰ QC-LDPC codes with girth 6 from the constructed 4-cycle free multi-type QC-LDPC codes. In continue, for 2 ≤ w≤6, some type-w QC-LDPC codes with girth 6 are constructed explicitly such that the constructed codes are flexible in terms of rate and length. To the best of our knowledge, for w = 5,6, this is the first paper which deals with the explicit construction of type-w QC-LDPC codes with girth 6 and high rates. Moreover, for w = 3, 4, the constructed type-w QC-LDPC codes have better(6,8)-cycle multiplicities than the codes with minimum achievable length recently constructed by cyclic difference families(CDFs). Simulation results show that the binary and non-binary constructed codes outperform the constituent underlying QC-LDPC codes.

Low-power, high-speed, and area-efficient sequential circuits by quantum-dot cellular automata: T-latch and counter study

Quantum-dot cellular automata(QCA)is a new nanotechnology for the implementation of nano-sized digital circuits.This nanotechnology is remarkable in terms of speed,area,and power consumption compared to complementary metal-oxide-semiconductor(CMOS)technology and can significantly improve the design of various logic circuits.We propose a new method for implementing a T-latch in QCA technology in this paper.The proposed method uses the intrinsic features of QCA in timing and clock phases,and therefore,the proposed cell structure is less occupied and less power-consuming than existing implementation methods.In the proposed T-latch,compared to previous best designs,reductions of 6.45%in area occupation and 44.49%in power consumption were achieved.In addition,for the first time,a reset-based T-latch and a T-latch with set and reset capabilities are designed.Using the proposed T-latch,a new 3-bit counter is developed which reduces 2.14%cell numbers compared to the best of previous designs.Moreover,based on the 3-bit counter,a 4-bit counter is designed,which reduces 0.51%cell numbers and 4.16%cross-section area compared to previous designs.In addition,two selective counters are introduced to count from 0 to 5 and from 2 to 5.Simulations were performed using QCADesigner and QCAPro tools in coherence vector engine mode.The proposed circuits are compared with related designs in terms of delay,cell numbers,area,and leakage power.

Efficacy of Valerian Extract on Sleep Quality after Coronary Artery bypass Graft Surgery: A Triple-Blind Randomized Controlled Trial

Objective:To assess the effect of valerian root extract on the sleep quality of patients after coronary artery bypass graft(CABG)surgery.Methods:The patients who participated in this triple-blind clinical trial were selected by permuted block randomization.The participants were assigned to the valerian(n=36)and placebo(n=36)groups.The valerian group received 530 mg of valerian capsules for 30 nights after CABG surgery,and the placebo group received 530 mg of the placebo capsules containing wheat flour.The Pittsburgh Sleep Quality Index(PSQI),the prothrombin time(PT)and partial thromboplastin time(PTT)were assessed on four occasions,including the baseline,the 3 rd,14 th and 30 th days following intervention.Results:The odds ratio of worsened sleep quality significantly varied over time(the interaction of time and group)in the valerian group compared to the placebo group in various dimensions including total sleep quality(P=0.001),sleep latency(P<0.01),sleep duration(P=0.020),sleep efficiency(P=0.001)and daytime dysfunction(P=0.025).No significant difference was observed in the alterations of the odds ratio of PT in the two groups over time.(P=0.371).Conclusion:The consumption of oral valerian root extract over 30 nights could significantly improve the patients'sleep quality safely after CABG surgery.

COMPARING TWO CLUSTERING-BASED TECHNIQUES TO TRACK MOBILE NODES IN INDUSTRIAL WIRELESS SENSOR NETWORKS

Tracking mobile nodes in dynamic and noisy conditions of industrial environments has provided a paradigm for many issues inherent in the area of distributed control systems in general and wireless sensor networks in particular. Due to the dynamic nature of the industrial environments, a practical tracking system is required that is adaptable to the changes in the environment. More specifically, given the limited resources of wireless nodes and the challenges created by harsh industrial environments there is a need for a technique that can modify the configuration of the system on the fly as new wireless nodes are added to the network and obsolete ones are removed. To address these issues, two cluster-based tracking systems, one static and the other dynamic, are proposed to organize the overall network field into a set of tracking zones, each composed of a sink node and a set of corresponding anchor nodes. To manage the wireless nodes activities and inter and intra cluster communications, an agent-based technique is employed. To compare the architectures, we report on a set of experiments performed in JADE （Java Agent Development Environment）. In these experiments, we compare two agent-based approaches （dynamic and static） for managing clusters of wireless sensor nodes in a distributed tracking system. The experimental results corroborate the efficiency of the static clusters versus the robustness and effectiveness of the dynamic clusters.