Bringing modular concurrency control to the next level

Database users face a tension between ease-of-programming and high performance: ACID transactions can greatly simplify the programming effort of database applications by providing four useful properties—atomicity, consistency, isolation, and durability, but enforcing these properties can degrade performance. This dissertation eases this tension by improving the performance of ACID transactions for scenarios where data contention is the bottleneck. The approach that we take is federating concurrency control (CC) mechanisms. It is based on the observation that any single CC mechanism is bound to make trade-offs that cause it to perform well in some cases but poorly in others. A federation opens the opportunity of applying each mechanism only to the set of transactions or workloads where it shines, while maintaining isolation. In particular, this work builds upon Modular Concurrency Control (MCC), a recent technique that federates CCs by partitioning transactions into groups, and by applying different CC mechanisms in each group. This dissertation addresses two critical shortcomings in the current embodiment of MCC. First, cross-group data conflicts are handled with a single, unoptimized CC mechanism that can significantly limit performance. Second, configuring MCC is a complex task, which runs counter to MCC’s purpose: to improve performance without sacrificing ease-of-programming. To address these problems, this dissertation presents Tebaldi, a new transactional database that brings Modular Concurrency Control to the next level, both figuratively and literally. Tebaldi introduces a new, hierarchical model to MCC that partitions transactions recursively to compose CC mechanisms in a multi-level tree. This model increases flexibility in federating CC mechanisms, which is the key to realizing the performance potential of federation. Tebaldi reduces configuration complexity by managing the MCC federation automatically: it can detect performance issues in the current workload in real-time, and automatically adjusts its configuration to improve its performance.Computer Science

Theoretical and Experimental Research of Error of Method of Thermocouple with Controlled Profile of Temperature Field

The method of study and experimental researches of the error of method of the thermocouple with controlled profile of temperature field along the main thermocouple are considered in this paper. Experimentally determined values of error of method are compared to the theoretical estimations done using Newton’s law of cooling. They converge well

The use of otolith shape to identify stocks of Konosirus punctatus

Konosirus punctatus is an important economic fish in the Northwest Pacific Ocean, especially along the coast of China, and an important substitute in the marine ecosystem. The aim of this study is to quantify the variation of sagittal shapes to discriminate the K. punctatus stocks between China coasts (Wei Hai, Yan Tai, Zhou Shan, Wen Zhou, Dong Ying, Hai Kou and Qing Dao) and Aomori (Am) in Japan by comparing the sagittal morphometric features. The sagitta variation of eight K. punctatus stocks was examined using nine shape indices (Roundness, Circularity, Form-factor, Rectangularity, Ellipticity, Radius ratio, Feret ratio, Aspect ratio and Surface density). Multiple comparisons on shape indices showed that three shape indices (Roundness, Feret ratio and Surface density) have significant differences between nine stocks. The comprehensive judgment accuracy rate is 54.5%. Based on the Fourier coefficient eight Fourier parameters can fit the shape of sagittal. The comprehensive judgment accuracy rate is 56.1%. The results showed that the otolith morphology was not significantly different between seven China stocks, while the China stocks showed a large sagittal morphological difference from the Japanese stock. It could be related to environmental factors and geographical conditions in various sea areas

Vibration characteristics analysis of high-pressure long-distance dense paste pipeline transporting with hydraulic active check valve

The pumping pressure required for long-distance pipeline transporting of dense paste is very high, the pumping system vibrates strongly, and the pipeline system is seriously damaged. In order to study the causes of vibration and the effect of hydraulic active check valves, pressure shock and pipeline vibration tests were conducted on the transporting pipeline in the field. The paper compared the data of sensors at each measurement point and analyzed the relationship between the action logic of each actuator of the transporting system and pressure shock and pipeline vibration. The first three orders of resonance bands of the pipeline system were obtained and radial vibration of the pump outlet pipeline was found to be greater than axial vibration. The S-pipe valve commutation was the direct cause of the pressure shock when the S-pipe valve took precedence over the piston commutation. Pressure shock increases with pumping volume. The opening of the check valve caused a large axial transient vibration and a small radial transient vibration on both sides of the valve. The above study of field data provides a reference for the selection of dense paste transporting pipeline parameters, the design of pipeline system and the research on the method of reducing the pipeline impact vibration

Multi-materials additive manufacturing of Ti64/Cu/316L by electron beam freeform fabrication

Titanium/steel multi-material, given full play to their superiorities, has tremendous value for parts exposed to complexity service environments, yet invariably, its common joining techniques are lack of design freedom. To this end, we employ electron beam freeform fabrication (EBF3) to successfully prepare this multi-material system for the first time, whose interfacial microstructure and property are systematically investigated. Applying Cu as an interlayer, instead of causing extensive cracking and delamination at the interface of Ti64/316L, can effectively suppress the formation of continuous Fe–Ti intermetallic compounds (IMCs), and thus improve the strength of Ti64/Cu/316L interfaces. For the Cu/316L interface, besides the characteristic spherical Cu-rich and Fe-rich solid solutions, a few Fe–Ti IMCs appear within the Fe-rich solid solutions owing to the long-range diffusion of minor Ti atoms. Correspondingly, the dendritic Cu-rich solid solutions can also be found at the Ti64/Cu interface, which is regarded as a critical interface due to the concomitant of complex Cu–Ti IMCs. These Cu–Ti IMCs have less negative effect on the Ti64/Cu interface property relative to Fe–Ti IMCs, and the local strain produced by the deformed α-Ti near the interface and Cu-rich solid solutions can effectively relieve the concentration of residual stress. Consequently, the Ti64/Cu interface exhibits maximum micro-hardness to 490 HV and superior shear strength to 196.5 ± 2.2 MPa, which was attributed to the reinforcement for the tip of keyhole molten pool, as well as the synergy between Cu-rich solid solution and interdendritic Cu–Ti IMCs

Proteomic response to acupuncture treatment in spontaneously hypertensive rats.

Previous animal and clinical studies have shown that acupuncture is an effective alternative treatment in the management of hypertension, but the mechanism is unclear. This study investigated the proteomic response in the nervous system to treatment at the Taichong (LR3) acupoint in spontaneously hypertensive rats (SHRs). Unanesthetized rats were subject to 5-min daily acupuncture treatment for 7 days. Blood pressure was monitored over 7 days. After euthanasia on the 7(th) day, rat medullas were dissected, homogenized, and subject to 2D gel electrophoresis and MALDI-TOF analysis. The results indicate that blood pressure stabilized after the 5th day of acupuncture, and compared with non-acupoint treatment, Taichong-acupunctured rat's systolic pressure was reduced significantly (P<0.01), though not enough to bring blood pressure down to normal levels. The different treatment groups also showed differential protein expression: the 2D images revealed 571 ± 15 proteins in normal SD rats' medulla, 576 ± 31 proteins in SHR's medulla, 597 ± 44 proteins in medulla of SHR after acupuncturing Taichong, and 616 ± 18 proteins in medulla of SHR after acupuncturing non-acupoint. In the medulla of Taichong group, compared with non-acupoint group, seven proteins were down-regulated: heat shock protein-90, synapsin-1, pyruvate kinase isozyme, NAD-dependent deacetylase sirtuin-2, protein kinase C inhibitor protein 1, ubiquitin hydrolase isozyme L1, and myelin basic protein. Six proteins were up-regulated: glutamate dehydrogenase 1, aldehyde dehydrogenase 2, glutathione S-transferase M5, Rho GDP dissociation inhibitor 1, DJ-1 protein and superoxide dismutase. The altered expression of several proteins by acupuncture has been confirmed by ELISA, Western blot and qRT-PCR assays. The results indicate an increase in antioxidant enzymes in the medulla of the SHRs subject to acupuncture, which may provide partial explanation for the antihypertensive effect of acupuncture. Further studies are warranted to investigate the role of oxidative stress modulation by acupuncture in the treatment of hypertension