No abstract

The origination and generation mechanisms of small magnetic flux ropes (SMFRs), which are important structures in solar wind, are not clearly known. In the present study, 1993 SMFRs immersed in coronal holes, active regions, and quiet-Sun solar wind are analyzed and compared. We find that the properties of SMFRs immersed in three types of solar wind are significantly different. The SMFRs are further classified into hot-SMFRs, cold-SMFRs, and normal-SMFRs, according to whether the O7+/O6+ is 30% elevated or dropped inside SMFRs as compared with background solar wind. Our studies show that the parameters of normal-SMFRs are similar to background in all three types of solar wind. The properties of hot-SMFRs and cold-SMFRs seem to be lying in two extremes. Statistically, the hot-SMFRs (cold-SMFRs) are associated with longer (shorter) duration, lower (higher) speeds and proton temperatures, higher (lower) charge states, helium abundance, and first ionization potential bias as compared with normal-SMFRs and background solar wind. The anticorrelations between speed and O7+/O6+ inside hot-SMFRs (normal-SMFRs) are different from (similar to) those in background solar wind. Most hot-SMFRs and cold-SMFRs should come from the Sun. Hot-SMFRs may come from streamers associated with plasma blobs and/or small-scale activities on the Sun. Cold-SMFRs may be accompanied by small-scale eruptions with lower-temperature materials. Both hot-SMFRs and cold-SMFRs could also be formed by magnetic erosions of interplanetary coronal mass ejections that do not contain or do contain cold-filament materials. The characteristics of normal-SMFRs can be explained reasonably by the two originations, both from the Sun and generated in the heliosphere.

No abstract

In order to reduce the system computation complexity and delay, we propose a scheme to decrease the iterative time of the carrier synchronization for low-density parity-check (LDPC) codes. The system will stop iteration if the log-likelihood ratio (LLR) message at the output of decoder satisfies the limitary conditions. Simulation results show that the proposed scheme is efficient and there is little degradation on the system performance. Moreover, the additional complexity is almost negligible.

In this paper, an improved stopping criterion for irregular LDPC decoding is proposed. This scheme considers the decoding property of irregular LDPC codes. When the lowest degree variable nodes reach stable state, the decoder gets the final decoding result. Therefore, the improved criterion is based on the convergence of the mean magnitude of the log-likelihood ratio (LLR) information of the lowest degree variable nodes at the output of each decoding iteration. Compared with existing schemes, this scheme decreases average number of iterations (ANI) and reduces computation complexity under slight performance degradation.