Soohyung Lee

Implementation of parallel processing in the basf2 framework for Belle II

Recent PC servers are equipped with multi-core CPUs and it is desired to utilize the full processing power of them for the data analysis in large scale HEP experiments. A software framework basf2 is being developed for the use in the Belle II experiment, a new generation B-factory experiment at KEK, and the parallel event processing to utilize the multi-core CPUs is in its design for the use in the massive data production. The details of the implementation of event parallel processing in the basf2 framework are discussed with the report of preliminary performance study in the realistic use on a 32 core PC server.

A common real time framework for SuperKEKB and Hyper Suprime-Cam at Subaru telescope

The real time data analysis at next generation experiments is a challenge because of their enormous data rate and size. The SuperKEKB experiment, the upgraded Belle experiment, requires to process 100 times larger data of current one. The offline-level data analysis is necessary in the HLT farm for the efficient data reduction. The real time processing of huge data is also the key at the planned dark energy survey using the Subaru telescope. The main camera for the survey called Hyper Suprime-Cam consists of 100 CCDs with 8 mega pixels each, and the total data size is expected to become comparable with that of SuperKEKB. The online tuning of measurement parameters is being planned by the real time processing, which was done empirically in the past. We started a joint development of the real time framework to be shared both by SuperKEKB and Hyper Suprime-Cam. The parallel processing technique is widely adopted in the framework design to utilize a huge number of network-connected PCs with multi-core CPUs. The parallel processing is performed not only in the trivial event-by-event manner, but also in the pipeline of the software modules which are dynamically placed over the distributed computing nodes. The object data flow in the framework is realized by the object serializing technique with the object persistency. On-the-fly collection of histograms and N-tuples is supported for the run-time monitoring. The detailed design and the development status of the framework is presented.

Development of high level trigger software for Belle II at SuperKEKB

The Belle collaboration has been trying for 10 years to reveal the mystery of the current matter-dominated universe. However, much more statistics is required to search for New Physics through quantum loops in decays of B mesons. In order to increase the experimental sensitivity, the next generation B-factory, SuperKEKB, is planned. The design luminosity of SuperKEKB is 8 x 1035cm−2s−1 a factor 40 above KEKBs peak luminosity. At this high luminosity, the level 1 trigger of the Belle II experiment will stream events of 300 kB size at a 30 kHz rate. To reduce the data flow to a manageable level, a high-level trigger (HLT) is needed, which will be implemented using the full offline reconstruction on a large scale PC farm. There, physics level event selection is performed, reducing the event rate by ~ 10 to a few kHz. To execute the reconstruction the HLT uses the offline event processing framework basf2, which has parallel processing capabilities used for multi-core processing and PC clusters. The event data handling in the HLT is totally object oriented utilizing ROOT I/O with a new method of object passing over the UNIX socket connection. Also under consideration is the use of the HLT output as well to reduce the pixel detector event size by only saving hits associated with a track, resulting in an additional data reduction of ~ 100 for the pixel detector. In this contribution, the design and implementation of the Belle II HLT are presented together with a report of preliminary testing results.

Effect of MeCP2 on TGF-β1-induced Extracellular Matrix Production in Nasal Polyp-derived Fibroblasts

Purpose Methyl-CpG-binding protein 2 (MeCP2), known as a transcriptional regulator, has been suggested to play an important role in myofibroblast differentiation in the lung. The purpose of this study was to investigate the role of MeCP2 in transforming growth factor (TGF)-β1-induced myofibroblast differentiation and extracellular matrix (ECM) production in nasal polyp-derived fibroblasts (NPDFs). Methods To identify the expression of MeCP2 in nasal polyp tissues, immunohistochemistry staining and Western blot were performed. TGF-β1-induced NPDFs were treated with 5-azacytidine, a DNA methylation inhibitor, and the expression levels of α-SMA and fibronectin were determined by semiquantitative reverse transcription polymerase chain reaction, immunofluorescent staining, and Western blotting. The total soluble collagen was analyzed by the Sircol collagen assay. MeCP2 silenced by MeCP2-specific small interference (si) RNA was verified by Western blot. Results The expression levels of MeCP2 increased in nasal polyp tissues compared to normal inferior turbinate tissues. 5-Azacytidine significantly inhibited the expression of α-SMA and fibronectin mRNA in a dose-dependent manner. In addition, 5-azacytidine suppressed collagen production and the expression of MeCP2 in the same manner. The expression levels of a-SMA and collagen production were significantly blocked by MeCP2 silencing in TGF-β1-induced NPDFs. Conclusions Our data suggest that MeCP2 plays an essential role in TGF-β1-induced myofibroblast differentiation and ECM production in NPDFs.

Development of a DC-to-DC Converter for the J-PARC Muon g-2/EDM Experiment

The J-PARC muon g-2/EDM experiment [1] is a new experiment to measure the anomalous magnetic moment (g-2) and electric dipole moment (EDM) of muon at J-PARC. The experiment is planned to start in 2016, and targets a sensitivity of 0.1 parts per million (ppm). In the muon storage ring, it is required to convert a high direct current (DC) voltage to a certain level (~1.5 V) of DC voltage to provide bias voltage to readout electronics. For the purpose, we are developing a step-down DC-to-DC converter utilizing a Buck converter [2]. To measure momenta of particles produced in the experiment, the detector components including the storage ring are under a 3 T magnet field. Since the converter contains an inductor that produces an additional magnetic field, the field has to be minimal not to corrupt the global magnetic field (B < 30 μT). In addition to the magnetic field, the experiment is quite sensitive to the electric field in the storage ring; therefore, the electric field produced by the converter has to be minimal as well (E << 1 V/m). In this poster, we present the development status of the DC-to-DC converter for the J-PARC muon g-2/EDM experiment.

Belle-II high level trigger at SuperKEKB

A next generation B-factory experiment, Belle II, is now being constructed at KEK in Japan. The upgraded accelerator SuperKEKB is designed to have the maximum luminosity of 8 × 1035 cm−2s−1 that is a factor 40 higher than the current world record. As a consequence, the Belle II detector yields a data stream of the event size ~1 MB at a Level 1 rate of 30 kHz. The Belle II High Level Trigger (HLT) is designed to reduce the Level 1 rate to 1/5 by performing the real time full event reconstruction and by applying the physics level event selection as the software trigger. In this paper, the development of the high level trigger system for Belle II and its performance is discussed.