Tars: Timeliness-aware Adaptive Replica Selection for Key-Value Stores

In current large-scale distributed key-value stores, a single end-user request may lead to key-value access across tens or hundreds of servers. The tail latency of these key-value accesses is crucial to the user experience and greatly impacts the revenue. To cut the tail latency, it is crucial for clients to choose the fastest replica server as much as possible for the service of each key-value access. Aware of the challenges on the time varying performance across servers and the herd behaviors, an adaptive replica selection scheme C3 is proposed recently. In C3, feedback from individual servers is brought into replica ranking to reflect the time-varying performance of servers, and the distributed rate control and backpressure mechanism is invented. Despite of C3's good performance, we reveal the timeliness issue of C3, which has large impacts on both the replica ranking and the rate control, and propose the Tars (timeliness-aware adaptive replica selection) scheme. Following the same framework as C3, Tars improves the replica ranking by taking the timeliness of the feedback information into consideration, as well as revises the rate control of C3. Simulation results confirm that Tars outperforms C3.Comment: 10pages,submitted to ICDCS 201

Gas Flow Model of Adhesion Sand Casing Well First Interface Micro Clearance and Application

In order to accurately describe the flow characteristics of the gas channeling in the adhesion sand casing well first interface, this article assumes the first interface annulus composed by adhesion sand casing and cement mantle is a microscopic rough gas flow channel. Using the lattice Boltzmann method, the flow model of gas channeling in first interface rough microscopic channel is established, the fundamental relationship of gas flow rate, gas flow pressure distribution and gas annulus pressure differential are calculated and analyzed. And the flow characteristics of gas under different adhesion sand density is simulated. The results show that the theoretical calculation and the numerical simulation results are in good agreement, the new calculation model reveals the essential rule of cementing gas channeling flow in adhesion sand casing well, which provides a new method for the gas channeling problem in process of subsequent oil well cementing.Key words: Adhesion sand casing well; Rough surface; Cementing first interface; Lattice Boltzmann; Gas channelin

The Model for Calculating Pore Evaluation of Fractal Rock Body Under Hydraulic Fracturing

In general, the pore medium of rock has fractal characters. In order to calculate the change regulations of porosity and evaluation character of the rock under hydraulic fracturing accurately, in this paper, a new damage variable was defined to describe the change of porosity. The model for calculating pore evaluation of the fractal fracturing rock body was established according to the principle of conservation of energy, considering the strain energy, the cracks propagation energy and the gravitational potential energy of fracturing fluid in the process of fracturing. The change regulations of fracturing parameters were calculated combining with the reservoir pore characters of Xinmin region. The change characters of the porosity were simulated by ANSYS, and the rationality and advancement of the new model was determined by deliverability analysis.Key words: Fractal rock body; Pore characters; Deliverability calculation; Hydraulic fracturin

The Study of Rock Body Damage Constitutive Model on Refracturing

In order to characterize the mechanical behavior of rock body damage evaluation and forming multiple fractures, in this paper in multiple fracturing , we have established rock body damage evaluation constitutive model, and given the point that the rock can bear secondary damage in multiple fracturing. Established the secondary damage evaluation model, and obtained the method for calculating the parameter of the crack in multiple fracturing. We have verified the model by a oil well in Jilin oilfield, the result has well anastomosis with the actual engineering.Key words: Multiple fracturing; Damage evaluation; Secondary damag

Using Shallow Platform Drilling Technology to Tap the Reserves of the Below Constructed Area of Fuyu Oilfield: Taking Chengping Block 12 as an Example

The special geographical conditions in the below constructed area of the surface have caused the poor oil-water well condition, incomplete well patterns, difficult measures for tapping potential, and no effective development of reserves, which have affected the comprehensive adjustment of Fuyu oilfield. In order to solve this problem, the shallow large platform horizontal well technology was studied in Fuyu oilfield by taking Chengping 12 reservoir as an example. This technology has been successfully applied under limited ground conditions, and underground reserves have been fully utilized. This study has laid a solid foundation for fuyu oilfield to increase recoverable reserves and achieve stable production during the 12th Five-year plan

Comparison of biochemical markers and technetium 99m methoxyisobutylisonitrile imaging in primary and secondary hyperparathyroidism

ObjectiveTo investigate the differences in biochemical marker levels and the extent of lesion visualization on technetium 99m methoxyisobutylisonitrile (99mTc-MIBI) imaging between primary hyperparathyroidism (PHPT) and secondary hyperparathyroidism (SHPT).MethodsNineteen patients with PHPT and 14 patients with SHPT were enrolled in the study, all of whom underwent routine 99mTc-MIBI dual-phase planar imaging, single-photon emission computed tomography combined with computed tomography (SPECT/CT fusion) imaging, and serum biochemical and hormonal investigations prior to surgery. The target-to-non-target (T/NT) ratios were calculated based on images from the early and delayed phases of 99mTc-MIBI planar imaging and also based on SPECT/CT fusion imaging. The volume of the parathyroid glands was measured following their excision.ResultsA total of 62 parathyroid glands were removed: 14 parathyroid adenomas and five parathyroid carcinomas in PHPT patients; and 18 parathyroid adenomas, 17 parathyroid hyperplasia lesions, and eight instances of nodular hyperplasia with adenoma in SHPT patients. The median volume of the lesions in PHPT and SHPT was 1.69 cm3 and 0.52 cm3 respectively, and the difference between them was statistically significant (P = 0.001). The median T/NT ratios calculated at the early phase of 99mTc-MIBI planar imaging, the delayed phase of 99mTc-MIBI planar imaging, and the subsequent SPECT/CT fusion imaging were 1.51, 1.34, and 2.75, respectively, in PHPT, and 1.46, 1.30, and 1.38, in SHPT, respectively. The T/NT ratio difference between PHPT and SHPT on the SPECT/CT fusion imaging was statistically significant (P = 0.002). The histopathology subtypes of the lesions were associated with significant differences in two areas: the T/NT ratios on the SPECT/CT fusion imaging and the volume of the lesions (P=0.002, P<0.001).ConclusionThe proportion of positive findings on 99mTc-MIBI dual-phase planar imaging and the T/NT ratios of 99mTc-MIBI SPECT/CT fusion imaging were higher in PHPT than in SHPT. The volume of parathyroid lesions in SHPT was smaller than in PHPT

The Study Fracture Evolution of Coal and Rock Mass Under Hydraulic Fracturing

The hydraulic fracturing technology is the main technical means of coalbed methane. However, it is hard to describe the fracture formation mechanism and evolution law in the process of fracturing. It caused the present studies restrict the effective mining of coalbed methane. This article is mainly study the process of fracture cracking and extending based on the angle of energy. It introduces the theory of entropy to analyse the micro defect evolution under hydraulic fracturing, and builds up the evolution model of the micro fracture number, angle, length and opening based on the theory of entropy. Then it analyses the main controlling factors of the fracture evolution. It will provide a new research approach for the law of hydraulic fracturing evolution.Key words: Entropy theory; Hydraulic fracturing; Damage evolutio

Hypoxia mitigation by manganese-doped carbon dots for synergistic photodynamic therapy of oral squamous cell carcinoma

Photodynamic therapy (PDT) is widely used for cancer treatment due to its non-invasive and precise effectiveness, however, hypoxia in the tumor microenvironment greatly limits the efficacy of photodynamic therapy. Compared with conventional photosensitizers, carbon dots (CDs) have great potential. Therefore, developing a water-soluble, low-toxicity photosensitizer based on CDs is particularly important, especially one that can enhance the photodynamic efficacy using the tumor microenvironment to produce oxygen. Herein, manganese-doped carbon dot (Mn-CDs, ∼2.7 nm) nanoenzymes with excellent biocompatibility were prepared by a solvothermal method using ethylenediaminetetraacetic acid manganese disodium salt hydrate and o-phenylenediamine as precursors. TEM, AFM, HR-TEM, XRD, XPS, FT-IR, ζ potential, DLS, UV-Vis, and PL spectra were used to characterize the Mn-CDs. Cancer resistance was assessed using the CCK-8 kit, calcein AM versus propidium iodide (PI) kit, and the Annexin V-FITC/PI cell apoptosis assay kit. The obtained Mn-CDs have excellent near-infrared emission properties, stability, and efficient 1O2 generation. Notably, the manganese doping renders CDs with catalase (CAT)-like activity, which leads to the decomposition of acidic H2O2in situ to generate O2, enhancing the PDT efficacy against OSCC-9 cells under 635 nm (300 mW·cm−2) irradiation. Thus, this work provides a simple and feasible method for the development of water-soluble photosensitizers with oxygen production, presenting good biosafety for PDT in hypoxic tumors

The Study of Rock Body Damage Constitutive Model in Multiple Fracturing

In order to characterize the mechanical behavior of rock body damage evaluation and forming multiple fractures, in this paper in multiple fracturing, we have established rock body damage evaluation constitutive model, and given the point that the rock can bear secondary damage in multiple fracturing. Established the secondary damage evaluation model, and obtained the method for calculating the parameter of the crack in multiple fracturing. We have verified the model by an oil well in Jilin oilfield, the result has fitted well with the actual engineering.Key words: Multiple fracturing; Damage evaluation; Secondary damag