Statistical Mechanics of Low-Density Parity Check Error-Correcting Codes over Galois Fields

A variation of low density parity check (LDPC) error correcting codes defined over Galois fields ($GF(q)$) is investigated using statistical physics. A code of this type is characterised by a sparse random parity check matrix composed of $C$ nonzero elements per column. We examine the dependence of the code performance on the value of $q$, for finite and infinite $C$ values, both in terms of the thermodynamical transition point and the practical decoding phase characterised by the existence of a unique (ferromagnetic) solution. We find different $q$-dependencies in the cases of C=2 and $C \ge 3$; the analytical solutions are in agreement with simulation results, providing a quantitative measure to the improvement in performance obtained using non-binary alphabets.Comment: 7 pages, 1 figur

A solution for secure use of Kibana and Elasticsearch in multi-user environment

Monitoring is indispensable to check status, activities, or resource usage of IT services. A combination of Kibana and Elasticsearch is used for monitoring in many places such as KEK, CC-IN2P3, CERN, and also non-HEP communities. Kibana provides a web interface for rich visualization, and Elasticsearch is a scalable distributed search engine. However, these tools do not support authentication and authorization features by default. In the case of single Kibana and Elasticsearch services shared among many users, any user who can access Kibana can retrieve other's information from Elasticsearch. In multi-user environment, in order to protect own data from others or share part of data among a group, fine-grained access control is necessary. The CERN cloud service group had provided cloud utilization dashboard to each user by Elasticsearch and Kibana. They had deployed a homemade Elasticsearch plugin to restrict data access based on a user authenticated by the CERN Single Sign On system. It enabled each user to have a separated Kibana dashboard for cloud usage, and the user could not access to other's one. Based on the solution, we propose an alternative one which enables user/group based Elasticsearch access control and Kibana objects separation. It is more flexible and can be applied to not only the cloud service but also the other various situations. We confirmed our solution works fine in CC-IN2P3. Moreover, a pre-production platform for CC-IN2P3 has been under construction. We will describe our solution for the secure use of Kibana and Elasticsearch including integration of Kerberos authentication, development of a Kibana plugin which allows Kibana objects to be separated based on user/group, and contribution to Search Guard which is an Elasticsearch plugin enabling user/group based access control. We will also describe the effect on performance from using Search Guard.Comment: International Symposium on Grids and Clouds 2017 (ISGC 2017

Identifying Subclasses of Long Gamma-Ray Bursts with Cumulative Light Curve Morphology of Prompt Emissions

We argue a new classification scheme of long gamma-ray bursts (LGRBs) using the morphology of the cumulative light curve of the prompt emission. We parametrize the morphology by the absolute deviation from their constant luminosity ($ADCL$) and derive the value for 36 LGRBs which have spectropic redshifts, spectral parameters determined by the Band model, 1-second peak fluxes, fluences, and 64-msec resolution light curves whose peak counts are 10 times larger than background fluctuations. Then we devide the sample according to the value of ADCL into two groups ($ADCL 0.17$) and, for each group, derive the spectral peak energy $E_{\rm p}$ - peak luminosity $L_{\rm p}$ correlation and the Fundamental Plane of LGRBs, which is a correlation between the spectral peak energy $E_{\rm p}$, the luminosity time $T_{\rm L}$ ($\equiv E_{\rm iso}/L_{\rm p}$ where $E_{\rm iso}$ is isotropic energy) and the peak luminosity $L_{\rm p}$. We find that both of the correlations for both groups are statistically more significant compared with ones derived from all samples. The Fundamental Planes with small and large ADCL are given by $L_{\rm p}=10^{52.53\pm 0.01}(E_{\rm p}/10^{2.71}{\rm keV})^{1.84\pm 0.03} (T_{\rm L}/10^{0.86}{\rm sec})^{0.29\pm0.08}$ with $\chi^2_{\nu}=10.93/14$ and $L_{\rm p}=10^{52.98\pm0.08}(E_{\rm p}/10^{2.71}{\rm keV})^{1.82\pm 0.09} (T_{\rm L}/10^{0.86}{\rm sec})^{0.85\pm 0.27}$ with $\chi^2_{\nu}=7.58/8$, respectively. This fact implies the existence of subclasses of LGRBs characterized by the value of $ADCL$. Also there is a hint for the existence of the intermediate-$ADCL$ class which deviates from both fundamental planes. Both relations are so tight that our result provides a new accurate distance measurement scheme up to the high redshift universe.Comment: 10 pages, 8 figures, 2 tables. Submitted to PAS

Dispersal of Phraortes illepidus (Phasmida: Phasmatidae) Eggs by Workers of the Queenless Ant, Pristomyrmex punctatus (Hymenoptera: Formicidae)

Eggs of some stick insects bear external appendages called capitula. Foraging worker ants attracted by capitula disperse eggs in a response similar to the responses of workers to elaiosome-bearing seeds of many plants. For this study, we conducted rearing experiments in the laboratory to elucidate the interspecific relation between the queenless ant, Pristomyrmex punctatus Smith, and the stick insect, Phraortes illepidus (Brunner von Wattenwyl) of which eggs bear capitula. Eggs of P. illepidus were proposed to P. punctatus in the laboratory. Capitula were removed from most of the eggs not only when ants were starved but also when ants were well-fed. In large rearing containers, eggs were transported by ants from their place of origin. Many eggs were transferred horizontally on the surface. Although some eggs were found in the artificial ant nests, it is likely that stick insects are not in active ant nests at the time of hatching in nature because of P. punctatus nest-moving habits. The percentage of eggs buried in the sand was small. Furthermore, most of the buried eggs were found at less than 3 cm depth. Results show that many P. illepidus hatchlings can reach host plants safely without being attacked by ant workers. These results suggest that P. punctatus can be a good partner of P. illepidus. Ants disperse eggs of slow-moving stink insects in exchange for some nutrition from capitula

Use of Wavelet Techniques in the Study of Seawater Flux Dynamics in Coastal Lakes

Lakes Shinji and Nakaumi form a coupled brackish lake system on the Japan Sea coast of Japan, and seawater frequently intrudes into these lakes. The study analyzed the influence of river discharge, tide level, and meteorological forcing on seawater flux at Nakaura Watergate. Continuous wavelet transform (CWT), wavelet coherence (WTC), cross-wavelet transform (XWT), and partial wavelet coherence (PWC) were used to analyze seawater intrusion. CWT reveals the characteristics of seawater flux, river discharge, tide level, and meteorological forcing. WTC and XWT showed the correlation between forcing variables and seawater flux. PWC analyzed the impact of river discharge, tide level, and meteorological forcing variables on seawater flux after controlling the effect of all other forcing variables. The results showed that tide level has an impact on seawater flux over 0.5-day and 1-day cycle throughout the analysis period, suggesting that astronomical tides play an important role in the salinity intrusion processes. The river discharge characteristics and its influence on seawater flux were clearly revealed especially during high river flows. Sometimes, atmospheric pressure and wind velocity affect tide level, thereby driving salinity transport. The study reveals the power of wavelet analysis in examining nonlinear time series such as salinity intrusion processes