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The mesophilic and thermophilic anaerobic co-digestion (Co-AD) of swine manure (SM) and rice straw (RS) mixtures was evaluated in lab-scale continuously stirred tank reactors through long-term semi-continuous experiments to investigate the effects of three RS ratios (25%, 33.3%, and 50%, based on total solids). The experimental results showed that an increase in the RS ratio reduced the biogas and methane production, and methane content in both Co-ADs and the effects of the increased RS ratio on the mesophilic Co-AD (Co-MAD) were slightly lower than those on the thermophilic Co-AD (Co-TAD). The digestate characteristics were also affected by the RS ratio. A reduction analysis demonstrated the higher importance of the RS ratio in the substrate with respect to gas production in Co-MAD compared to Co-TAD. The increase in the RS ratio increased the relative abundance of Clostridium_sensu_strricto_1, and changed the predominant archaea and methanogenesis pathways in both Co-ADs.

The temperature-phased anaerobic digestion (TPAD) of food waste was studied for the purpose of comparing with single-stage mesophilic and thermophilic anaerobic digestion. The biogas and methane yields in the TPAD during the steady period were 0.759 ± 0.115 L/g added VS and 0.454 ± 0.201 L/g added VS, which were lower than those in the two single-stage anaerobic digestion. The improper sludge retention time may be the reason for the lower biogas and methane production in TPAD. The removal of volatile solids in the TPAD was 78.55 ± 4.59% and the lowest among the three anaerobic digestion processes. The reaction ratios of the four anaerobic digestion steps in the TPAD were all lower than those in the two single-stage anaerobic digestion. The energy conversion efficiency of the degraded substrate in the TPAD was similar with those in single-stage mesophilic and thermophilic anaerobic digestion systems.

Vitellogenin (Vtg) is a biomarker for environmental estrogens, and its sensitive detection method is vital for the detection of weak estrogenic activity. This study aimed to develop sensitive electrochemical immunosensors for marine medaka (Oryzias melastigma) Vtg based on novel nanomaterials. Firstly, Cu2O–BSA nanoparticles (NPs) with a diameter of 120−150 nm was synthesized, and monoclonal antibody against lipovitellin (anti-Lv mAb) was prepared. Then two simple and efficient label-free immunosensors for the detection of Vtg were established using Cu2O–BSA NPs and gold nanoparticle (Au NPs) as signal amplification elements and anti-Lv mAb as the detection probe. These two immunosensors have good sensitivity, selectivity, reproducibility for Vtg quantification, and are easy to use. Moreover, the BSA/Anti-Lv mAb/Au/Cu2O–BSA/GCE immunosensor exhibited a linear range from 0.128 to 5 × 104 pg/mL, with the lowest detection limit (LOD) of 0.09 pg/mL, which is considerably lower than those of the previously reported Vtg detection techniques. Finally, the performance of the immunosensor was evaluated by quantifying Vtg concentrations in plasma of male marine medaka exposed three estrogenic bisphenols. The results demonstrated that the BSA/Anti-Lv mAb/Au/Cu2O–BSA/GCE immunosensor was an easily-operated, ultrasensitive and accurate detection method for weak estrogenic activity.

The anaerobic co-digestion (coAD) of swine manure (SM) and rice straw (RS) is appealing for renewable energy recovery and waste treatment worldwidely. Improving its performance is very important for its application. In this study, long-term semi-continuous experiments were conducted to evaluate the improving effects of digestate recirculation on the performance, energy recovery, and microbial community of two-stage thermophilic-mesophilic coAD of swine manure (SM) and rice straw (RS). The experimental results indicated that the coAD systems of SM and RS (mixing ratio of 3:1) with or without digestate recirculation could not realize phase separation. The reactors of both coAD systems were characterized by pH values ranging from 7.74 to 7.85, methane production as 0.41 ± 0.02 and 0.44 ± 0.03 L/L/d, and stable operation. Notably, digestate recirculation increased total methane production, organic matter removal, and reaction rate of the coAD system by 9.92 ± 5.08, 5.22 ± 1.94, and 9.73–12.60%, respectively. Digestate recirculation improved the performance of the coAD by significantly increasing the abundance of Methanosarcina (from 4.1% to 7.5%–10.7% and 35.7%) and decreasing that of Methanothermobacter (from 94.2% to 87.3%–83.6% and 56.8%). Thus, the main methanogenesis pathway of the coAD system was changed by digestate recirculation and the methane production was effectively improved. Although the energy input of the coAD system increased by 30.26%, digestate recirculation improved the energy balance of the total system by 6.83%.

Transition metal oxides with high theoretical specific capacity, when used as anode materials in sodium-ion batteries, usually suffer from poor structural stability and inferior rate capacity. The use of hollow nanostructured metal oxides incorporated into porous carbon frameworks is a promising strategy for addressing this issue. Herein, we fabricated hollow Co3O4 nanoparticles anchored in a porous carbon nanofiber matrix (Co3O4@PCNF) by electrospinning, metal–organic framework incorporation, and two-step calcination. The porous carbon nanofiber matrix can facilitate structural stability and provide multiple channels for fast electron/ion transport. The hollow Co3O4 nanoparticles resulting from the Kirkendall effect can shorten the Na-ion transport path for achieving fast reaction kinetics. The Co3O4@PCNF exhibits a reversible specific capacity of 487 mAh g−1 at 0.05 A g−1 with a high initial Coulombic efficiency of 91.6%, outstanding rate performance (220 mAh g−1 at 5 A g−1), and stable cycling, thereby making it suitable as an anode for sodium-ion batteries. Moreover, a full cell fabricated using a Co3O4 @PCNF anode and Na3V2(PO4)2O2F cathode delivers a reversible capacity of 205 mAh g−1 at 0.5 A g−1. We believe that our approach can provide a design pathway to improve the performance of Co3O4-based anodes for sodium-ion batteries and offer a new strategy to produce hollow-structure electrode materials for other energy-storage devices.

The deterioration of sludge settleability is a common problem in sludge reduction systems with metabolic uncouplers (MUs). The deterioration mechanisms were studied by conducting laboratory-based tests for 85 days. The sludge volume index (SVI30) increased from 88.0 mL/g SS to 149.5–158.9 mL/g SS with MUs. The addition of MUs decreased the N-acyl-L-homoserine lactone (AHLs) content of the sludge by increasing the AHL-degrading bacteria (Paenibacillus spp., Bacillus spp. and Microbacterium sp.) and decreasing or eliminating the AHL-producing bacteria (Paracoccus sp.). Meanwhile, the addition of MUs increased the extracellular polymeric substances (EPS) of sludge and decreased its protein-polysaccharide ratio (PN/PS). The decrease of AHL content and the changes of EPS resulted in the deterioration of sludge settleability in the MUs systems. The statistical analysis suggested the decrease of AHL content was more important than the change of sludge EPS on deteriorate the sludge settleability.

New non-volatile memory (e.g., phase-change memory) provides fast access, large capacity, byte-addressability, and non-volatility features. These features, fast-byte-persistency, will bring new opportunities to fault tolerance. We propose a fine-grained checkpoint based on non-volatile memory. We extend the current virtual memory manager to manage non-volatile memory, and design a persistent heap with support for fast allocation and checkpointing of persistent objects. To achieve a fine-grained checkpoint, we scatter objects across virtual pages and rely on hardware page-protection to monitor the modifications. In our system, two objects in different virtual pages may reside on the same physical page. Modifying one object would not interfere with the other object. This allows us to monitor and checkpoint objects smaller than 4096 bytes in a fine-grained way. Compared with previous page-grained based checkpoint mechanisms, our new checkpoint method can greatly reduce the data copied at checkpoint time and better leverage the limited bandwidth of non-volatile memory.

BRCA1/2 mutations represent a high risk of breast cancer and are related to early-onset breast cancer. However, few studies have reported the relationship between BRCA1/2 mutations and their clinical characteristics in early-onset breast cancers. This study is the first article that characterizes the risk factor profiles in Chinese patients selected by the age of onset (≤ 40 years old). We found some differences in the prevalence of germline BRCA1/2 mutations between Asian and Western countries.A total of 1371 consecutive unselected Chinese early-onset breast cancer patients were enrolled from the Fujian Medical University Union Hospital, China, and screened for germline BRCA1/2 mutations. Full-exome sequencing in next-generation sequencing technology was performed in all patients to examine BRCA1/2 mutations.In our study, 25 (1.8%) and 61 (4.4%) patients were identified with BRCA1 and BRCA2 mutations, respectively, among the unselected early-onset breast cancer patients. BRCA1 mutations were associated with pregnancies (p = 0.026), and BRCA1 carriers had a higher likelihood of being HR positive (p 0.001), HER2 negative (p 0.001), or high grade (p = 0.002) than noncarriers. Among BRCA2 mutations, the age of onset was younger in carriers than in noncarriers (p = 0.017), and BRCA2 carriers were more likely to have lymph node metastasis (p = 0.004). HR-positive or HER2-negative patients were likely to be positive for BRCA2 mutations (p 0.001). Overall, 14 BRCA1 mutations and 8 BRCA2 mutations were first reported in our study CONCLUSION: This study provided some information about the spectrum of BRCA1/2 mutations and characterized the risk factors for early-onset breast cancer in China.

Real-time collaborative programming is an emerging approach that supports a team of programmers to view and edit shared source code at the same time. Each programmer can edit any part of the source code, and changes become instantly visible at other collaborating sites. With a broad range of application scenarios and benefits, real-time collaborative programming has attracted increasing interest from academia and industry. Lightweight integrated development environments (lightweight IDEs) have rapidly grown in popularity in the recent years, but there are serious problems and limitations with existing real-time collaboration support for lightweight IDEs. In this study, we contribute a novel real-time collaborative programming environment named CoVSCode that supports unconstrained and flexible real-time collaboration based on Visual Studio Code, one of the most popular and widely used lightweight IDEs. We present design objectives and rationales, the workflow and functional design from collaborating programmers&rsquo, perspectives, major technical issues and solutions, and prototype implementation, as well as a set of experimental evaluations that have demonstrated the technical feasibility and good performance of the prototype system. All approaches, techniques and solutions derived in this work are generic, which can also be applied in building real-time collaborative programming environments for other lightweight IDEs.

QuiescentNVM is a user-space runtime providing transparent failure-consistency guarantees for lock-based parallel programs executing on hybrid combinations of traditional DRAM and byte-addressable non-volatile memory (NVM) technologies. A dual-versioning mechanism performs in-place persistent writes over one copy, and consistent fallback guarantees are provided by the other copy. Thus, the two writes to NVM present in logging-based solutions (such as for durable memory transactions) are reduced to a single write. Further, we avoid the need to rewrite legacy applications to exploit durable transactions. Our system relies on its dual-copy framework operation that safely persists data during global quiescent states, where no thread must hold a lock on persistent data. For applications with low lock-contention, global lock-free quiescent states will occur sufficiently frequently, and we deliver better performance and lower wear to NVM than current systems. We do not cover high-lock contention scenarios while enforcing quiescent states to occur.

Peripheral nerve injury and regeneration are complex processes and involve multiple molecular and signalling components. However, the involvement of long non‐coding RNA (lncRNA) in this process is not fully clarified. In this study, we evaluated the expression of the lncRNA maternally expressed gene 3 (MEG3) in rats after sciatic nerve transection and explored its potential mechanisms. The expression of lncRNA MEG3 was up‐regulated following sciatic nerve injury and observed in Schwann cells (SCs). The down‐regulation of lncRNA MEG3 in SCs enhanced the proliferation and migration of SCs via the PTEN/PI3K/AKT pathway. The silencing of lncRNA MEG3 promoted the migration of SCs and axon outgrowth in rats after sciatic nerve transection and facilitated rat nerve regeneration and functional recovery. Our findings indicated that lncRNA MEG3 may be involved in nerve injury and injured nerve regeneration in rats with sciatic nerve defects by regulating the proliferation and migration of SCs. This gene may provide a potential therapeutic target for improving peripheral nerve injury.

In gravity aided inertial navigation, a good path planning, which makes the path pass the area where the gravity changes drastically, in matching area will improve the matching accuracy effectively. The underwater vehicle is restricted by kinematics and other constraints, and cannot move in any direction. However, The path planned by the traditional path planning algorithm is a broken line and is not suitable for actual underwater vehicle navigation. Aiming at underwater vehicle path planning problem, this paper proposes a gravity aided inertial navigation path planning algorithm which is based on vehicle constraints and Bezier curves. The $A^{\ast}$ algorithm is optimized by vehicle constraints and gravity characteristics. The Bezier curve is used to smooth the planned path, making the planned path more suitable for the actual situation. Simulation experiments show that the matching accuracy is effectively improved by the planned path based on vehicle constraints and Bezier curve.

Based on the historical load data collected in July and August 2020 in Chongqing, and in view of the characteristics of the regional load in summer Chongqing, a new short-term load forecasting method was put forward in this paper, which is based on BP neural network and takes into account social activities and meteorological factors. The simulation results show that the proposed short-term load forecasting method can accurately realize the daily maximum load forecasting, it provides a theoretical reference for load forecasting and power resource optimization of smart grid in the future.

This paper evaluates the causal effects of China's anti-corruption campaign on corporate environmental costs. Using primary data and the investigations of the anti-corruption campaign as a quasi-natural experiment, our difference-in-differences estimation shows that: (1) the inspections encourages heavy pollution enterprises to increase investment in environmental protection; (2) our findings are particularly pronounced in subsamples of SOEs, non-SOEs with political connections, firms with more related party transaction, with less government’ intervention, with more financing constrains and information asymmetry. Overall, this paper links the corruption and environmental protection, which is helpful for the governments to improve the environment circumstances through political channel.

To investigate biohythane production and microbial behavior during temperature-phased (TP) anaerobic co-digestion (AcD) of rice straw (RS) and pig manure (PM), a mesophilic-thermophilic (M1-T1) AcD system and a thermophilic-mesophilic (T2-M2) AcD system were continuously operated for 95 days in parallel. The maximal ratio (8.44%v/v) of produced hydrogen to methane demonstrated the feasibility of biohythane production by co-digestion of RS and PM. T2-M2 exhibited higher hydrogen (16.68 ± 1.88 mL/gVS) and methane (197.73 ± 11.77 mL/gVS) yields than M1-T1 (3.08 ± 0.39 and 109.03 ± 4.97 mL/gVS, respectively). Methanobrevibacter (75.62%, a hydrogenotrophic methanogen) dominated in the M1 reactor, resulting in low hydrogen production. Hydrogen-producing bacteria (Thermoanaerobacterium 32.06% and Clostridium_sensu_stricto_1 27.33%) dominated in T2, but the abundance of hydrolytic bacteria was low, indicating that hydrolysis could be a rate-limiting step. The thermophilic acid-producing phase provided effective selective pressure for hydrogen-consuming microbes, and the high diversity of microbes in M2 implied a more efficient pathway of methane production.

Attention on semiconductor nanocrystals have been largely focused because of their unique optical and electrical properties, which can be applied as light absorber and luminophore. However, the band gap and structure engineering of nanomaterials is not so easy because of their finite size. Here we demonstrate an approach for preparing ternary AgInS2 (AIS), quaternary AgZnInS (AZIS), AgInS2/ZnS and AgZnInS/ZnS nanocompounds based on cation exchange. First, pristine Ag2S quantum dots (QDs) with different sizes were synthesized in one-pot, followed by the partial cation exchange between In(3+) and Ag(+). Changing the initial ratio of In(3+) to Ag(+), reaction time and temperature can control the components of the obtained AIS QDs. Under the optimized conditions, AIS QDs were obtained for the first time with a cation disordered cubic phase and high photoluminescence (PL) quantum yield (QY) up to 32% in aqueous solution, demonstrating the great potential of cation exchange in the synthesis for nanocrystals with excellent optical properties. Sequentially, Zn(2+) ions were incorporated in situ through a second exchange of Zn(2+) to Ag(+)/In(3+), leading to distinct results under different reaction temperature. Addition of Zn(2+) precursor at room temperature produced AIS/ZnS core/shell NCs with successively enhancement of QY, while subsequent heating could obtain AZIS homogeneous alloy QDs with a successively blue-shift of PL emission. This allow us to tune the PL emission of the products from 483 to 675 nm and fabricate the chemically stable QDs core/ZnS shell structure. Based on the above results, a mechanism about the cation exchange for the ternary nanocrystals of different structures was proposed that the balance between cation exchange and diffusion is the key factor of controlling the band gap and structure of the final products. Furthermore, photostability and in vitro experiment demonstrated quite low cytotoxicity and remarkably promising applications in the field of clinical diagnosis.

Unlike terrestrial networks that mainly rely on radio waves for communications, underwater networks utilize acoustic waves, which have comparatively lower loss and longer range in underwater environments. However, acoustic waves incurs long propagation delays that typically lead to low throughput and higher energy cost of transmission than reception. Thus, collision and retransmission should be reduced in order to reduce energy cost and improve throughput. Receiver-based protocols, like receiver-initiated packet train and cluster-based on-demand time sharing, can significantly reduce collision and retransmission. But they are either time-consuming or energy consuming because nodes are controlled to turn into receiver mode by control packets or a timer regardless of load. In this paper, we propose an underwater practical MAC protocol (UPMAC), whose objective is to be adaptive to the network load conditions by providing two modes (high and low load modes) and switching between them based on different offered load. Turn-around time overhead is reduced and it is less vulnerable to control packet corruption by using the technique of piggyback. UPMAC uses receiver-based approach in high load mode, leading to a low data collision rate in both one-hop and multihop situation. Extensive simulations show that UPMAC can achieve better performance in both general and Sea Swarm topologies.

Slickwater fracturing can create complex fracture networks in shale. A uniform proppant distribution in the network is preferred. However, proppant transport mechanism in the fracture network is still uncertain, which restricts the optimization of sand addition schemes. In this study, slot flow experiments are conducted to analyze the proppant placement in the complex fracture system. Dense discrete phase method is used to track the particle trajectories to study the transport mechanism into the branch. The effects of the pumping rate, sand ratio, sand size, and branch angle and location are discussed in detail. Results demonstrate that: (1) under a low pumping rate or coarse proppant conditions, the dune development in the branch depends on the dune geometry in the primary fracture, and a high proportion of sand can transport into the branch; (2) using a high pumping rate or fine proppants is beneficial to the uniform placement in the fracture system; (3) sand ratio dominates the proppant placement in the branch and passing-intersection fraction of a primary fracture; (4) more proppants may settle in the near-inlet and large-angle branch due to the size limit. Decreasing the pumping rate can contribute to a uniform proppant distribution in the secondary fracture. This study provides some guidance for the optimization of proppant addition scheme in the slickwater fracturing in unconventional resources.

To evaluate the correlation between expression of p53, Livin, Excision repair cross-complementation group 1 (ERCC1), BRCA1 and Poly (ADP-ribose) polymerase 1 (PARP 1) in epithelial ovarian cancer (EOC) tissues with platinum-based chemotherapy and prognosis in patients who received either comprehensive surgical staging or cytoreductive surgery.The protein expressions level of five potential regulators involved in chemo-resistance, including p53, Livin, ERCC1, BRCA1 and PARP1 in EOC tissues from 66 patients were evaluated using immunohistochemistry method. We also measured preoperative CA125 level measured by an electrochemiluminescence immunoassay (ECLIA) in all patients. Cox proportional hazard regression model was established to identify whether these proteins are associated with overall survival.Chemo-resistance and poor overall survival were shown to be significantly related with positive expressions of p53, Livin, ERCC1, BRCA1 and PARP1. The evaluation of risk factors on the chemo-resistance showed that ERCC1 and BRCA1 are strong risk factors (OR: 21.12 and 21.61, all P0.01), while the positive expression of ERCC1, BRCA1 and PARP1 was significantly highly associated with the overall survival (HR: 3.9, 3.7 and 2.6, all P0.05, respectively). CA125 levels were significantly higher in patients with positive expression of P53, BRCA1, ERCC1 or Livin compared with those with negative expression (471:146, 667:260, 494:261 and 4589:89 U/ml, respectively, all P0.05).The elevated expression levels of ERCC1 and BRCA1 were identified as significant risk factors for chemo-resistance in EOC. Reduced expression levels of ERCC1, BRCA1 and PARP1 were significantly associated with better overall survival. The CA125 levels were significantly higher in patients with EOC specimens that were positive of p53, BRCA1, ERCC1 and Livin.

This study simulates the hydraulic fracturing process based on ABAQUS, and obtains the results of hydraulic fracturing fracture propagation under the influence of multi-parameters. Our research shows that:The effect of reservoir modification increases with the increase of injection rate of fracturing fluid. Under the condition of 8m3/min or above, the fracture can communicate with the fault zone 100m away from the bottom of the well. Under the condition of 10cP, the effect of fracture propagation in formation is good. Under the condition of 50cP, the effect of fracture propagation in fracture zone is good. Under the condition of 200cP, the effect of crack propagation is poor. When the injection volume of fracturing fluid is between 0 and 1440m3, the effect of fracture propagation increases gradually. When the injection volume of fracturing fluid is larger than 1440m3, the contribution of continuous injection become weak. The maximum vertical crustal stress results in the fracture extending to the depth. The maximum horizontal crustal stress results in the horizontal propagation of fractured fractures. This study analyzed the influence of formation parameters and hydraulic fracturing parameters on fracture propagation. It also plays an active role in predicting the effect of hydraulic fracturing.

Recently, tetrakis(hydroxymethyl)phosphonium sulfate (THPS) was found to play an important role in the sludge pretreatment process. However, the effects of THPS pretreatment on the characteristics of sewage sludge are still insufficiently understood. The properties of sludge after pretreatment with different concentrations of THPS were investigated in this study. The results showed that pH, dewatering ability, and particle size of sludge decreased with increase in THPS concentration. The volatile suspended solids (VSS) and total suspended solids (TSS) of sludge also decreased slightly with increase in THPS concentration. The specific oxygen uptake rate (SOUR) results suggested that lower THPS concentrations (≤ 1.87 mg/g VSS) enhanced the activity of sludge, but higher concentrations (≥ 1.87 mg/g VSS) inhibited it. Gram-negative bacteria with peritrichous flagellation (such as Pseudomonas, Escherichia, and Faecalibacterium) were extremely sensitive to THPS. The decrease in specific most probable numbers (MPNs) of pathogens (total coliforms and Escherichia coli) with the increase in THPS concentration also proved the sterilization ability of THPS in the sludge pretreatment process. Pretreatment of sludge with concentrations of THPS higher than 37.41 mg/g VSS would meet the pathogen requirements for land application of Class A biosolids.

Three alkaline treatments (pH 10, 11, and 12 for 1 h) were used to treat return sludge alone to reduce sludge production in laboratory-scale anaerobic–anoxic–oxic processes. After 99 days of operation, alkaline treatments at pH 10 and 11 led to accumulative excess sludge production and sludge yield reduction of 18.8%–31.7% and 14.7%–27.8%, respectively. However, alkaline treatment at pH 12 led to system breakdown because of sludge bulking. The alkaline treatment at pH 10 did not affect the chemical oxygen demand and NH4+-N removals of the system and sludge volume index (SVI) of aerobic activated sludge. However, alkaline treatments at pH 11 and 12 obviously deteriorated the wastewater treatment efficiencies and sludge SVI. Although the three treatments increased the effluent pH by 0.08 to 0.38, the effluent pH of three systems were all lower than 9.00. The treatments at pH 10 and 11 increased the specific oxygen uptake rate of activated sludge, whereas the treatment at pH 12 decreased this rate.

As a scenario experience project running on PC, this work takes roaming the Innovation and Entrepreneurship Education Center of the Department of Psychology of Beijing Normal University as the background, and takes the real scene inside the education center as the prototype, so that visitors can experience the roaming realized by virtual reality technology.

In this paper, a network illegal access detection method based on PSO-SVM algorithm in the power monitoring system is proposed, where the particle swarm optimization (PSO) algorithm is used to optimize the parameters of support vector machine (SVM). And the proposed method is used to classify normal data flow and abnormal data flow in the network to detect whether there is illegal access behavior in the power monitoring system. Compared with the original SVM-based method and LS-SVM-based method, the proposed method not only improves the convergence speed of the network training, but also improves the accuracy rate. The proposed method can fleetly discovery and locate the illegal access behavior in the power monitoring system, which is a meaningful study in improving the security of the power monitoring system.

Modern computer systems are suffering from various failures and are increasingly prone to error. This paper introduces a high efficient incremental checkpoint mechanism for fault tolerance. By leveraging the new hardware support for various page sizes, we make dynamic transformation between different sized pages and thus achieve the best balance of overhead between modification tracking and data dumping in incremental checkpoint. Experiments show that our new checkpoint mechanism could achieve an average speedup of 2.2x with the space overhead of 34% over traditional incremental checkpoint, showing great potential to be widely adopted.

Page protection is often used to achieve memory access monitoring in many applications, dealing with program-analysis, checkpoint-based failure recovery, and garbage collection in managed runtime systems. Typically, low overhead access monitoring is limited by the relatively large page-level granularity of memory management unit hardware support for virtual memory protection. In this paper, we improve upon traditional page-level mechanisms by additionally using hardware support for virtualization in order to achieve fine and flexible granularities that can be smaller than a page. We first introduce a memory allocator based on page protection that can achieve fine-grained monitoring. Second, we explain how virtualization hardware support can be used to achieve dynamic adjustment of the monitoring granularity. In all, we propose a process-level virtual machine to achieve dynamic and fine-grained monitoring. Any application can run on our process-level virtual machine without modification. Experimental results for an incremental checkpoint tool provide a use-case to demonstrate our work. Comparing with traditional page-based checkpoint, our work can effectively reduce the amount of checkpoint data and improve performance.

With shrinking design rules, the overall patterning requirements are getting aggressively tighter and tighter. For the 5-nm node and beyond, on-product overlay below 2.5nm is required. Achieving such performance levels will not only need optimization of scanner performance but a holistic tuning of all process steps. In previous work, it has been shown that process-induced pattern asymmetry has significant impact on overlay performance at wafer edge and can be partially compensated by applying high-order scanner corrections or optimizing metrology targets. Today, we present the reduction of process-induced pattern asymmetry in a tunable etch system and demonstrate the related on-product overlay improvement combined with scanner corrections. In our work we utilize etch tools (Lam Kiyo® conductor etch systems) with proprietary edge tuning technology that can be used to reduce the etch-related asymmetry at the wafer edge. In combination to this unique method, we evaluate the impact of high order corrections per exposure field to compensate for process asymmetry at the wafer edge with a state-of-the-art 1.35 NA immersion scanner (NXT:1970Ci). The study is done on dedicated test wafers with 10-nm logic node design. We use angle-resolved scatterometry (YieldStar® S-250), atomic force microscopy, and SEM cross-sections to characterize process asymmetry. We present experimental investigation of the effect of etch tuning and scanner corrections on the pattern shift and the resulting overlay. In particular, we present results showing a reduction of etch-induced pattern shift by 12nm at wafer radius 147mm. Results show that asymmetry can be addressed by both, litho compensation and etch tuning, and bring on-product overlay down to the required level. We discuss the benefit of the correction techniques especially for thick hard mask layers (the pattern shift scales linear with hard mask thickness) and evaluate a combined correction scenario, where preventive etch tuning and feed-back based scanner corrections are used. We conclude that a holistic tuning of all process steps will be required to fulfill overlay requirements of future nodes.

SUMMARY The nondeterminism of message-passing communication brings challenges to program debugging, testing and fault-tolerance. This paper proposes a novel deterministic message-passing implementation (DMPI) for parallel programs in the distributed environment. DMPI is compatible with the standard MPI in user interface, and it guarantees the reproducibility of message with high performance. The basic idea of DMPI is to use logical time to solve message races and control asynchronous transmissions, and thus we could eliminate the nondeterministic behaviors of the existing message-passing mechanism. We apply a buffering strategy to alleviate the performance slowdown caused by mismatch of logical time and physical time. To avoid deadlocks introduced by deterministic mechanisms, we also integrate DMPI with a lightweight deadlock checker to dynamically detect and solve these deadlocks. We have implemented DMPI and evaluated it using NPB benchmarks. The results show that DMPI could guarantee determinism with incurring modest runtime overhead (14% on

Web page segmentation aims to break a page into sections that can reveal the information presentation structure and appear coherent to readers. In this paper, we propose a new web page segmentation framework based on the process of analyzing and understanding web page structure. After extracting the segmentation graph structure, we formulate the label assignment task which determines whether each boundary should segment current block or not on a graph as a structured learning problem. Computation of highest scoring label assignment relies on Viterbi algorithm and joint feature function captures the dependency among boundaries. To solve the learning of parameters, we adopt a learning model based on perceptron algorithm. Furthermore, utilizing the previous framework, we propose a web information crawling application framework which integrates web page segmentation and semantic block classification process.

Currently, various Medium Access Control (MAC) protocols have been proposed for underwater Wireless sensor networks. Unlike terrestrial networks, underwater networks utilize acoustic waves, which have comparatively lower loss and longer range in underwater environments. However, the use of acoustic waves incurs long propagation delays that typically lead to low throughput especially in protocols that require receiver feedback such as multimedia stream delivery and the energy cost of transmission is much higher than receptions. Thus, collision and retransmission should be reduced in practice in order to reduce energy cost and improve throughput. Based on these motivations, we propose a novel MAC protocol called NCDC-MAC. NCDC-MAC leverages network coding and duty cycle, the combination of which is seldom explored, to solve these challenges. Heterogeneous wireless networks and node roles are considered while designing our algorithms. Meanwhile, fairness including schedule and service time assignment is supported in our approach. Extensive simulations show that our approach can achieve significantly better performance.

Huge pages have been widely supported by architecture and operating system. Huge pages map large fixed virtual memory regions, on the orders of 2MB to 1GB on Intel x86-64 architecture. The page size is the key to striking the balance between trade-off pairs. For example, initially, the use of huge pages aims to mitigate address translation overhead for memory-intensive workloads with large memory footprints. The huge pages do benefit to the TLB hit rate as well as the TLB miss penalty but occupy a huge amount of contiguous physical memory. Moreover, the use of huge pages influences the overhead of page-based technologies. For example, the incremental checkpoint keeps track of memory access information at the granularity of the memory page. The page size is the basic unit ofthe range of monitoring. Itdetermines the frequency of page faultsand the copying overhead, which are another trade-off pair. This paper establishes the Dynamic Page Size Adjustment (DPSA) framework in Linux OS. This work provides merge and split operations in OS that change the size of memory pages during runtime. We also support on and off DPSA modes to enable an automaticadjustment of the page size based on memory access pattern. These functions are all exposed via system-level APIs. This framework is free to use for application programmers. They can either turn off the mode tocall the APIsaccording to their applications' characteristic, or they can turn on the mode to give freedom to the DPSA.

The Mean Time to Failure continues to decrease as the scaling of computing systems. To maintain the reliability of computing systems, checkpoint has to be taken more frequently. Incremental checkpointing is a well-researched technique that makes frequent checkpointing possible. Fine-grained incremental checkpointing minimizes checkpoint size but suffers from significant monitoring overhead. We observe the memory access at page granularity and find that the size of contiguous memory regions visited by applications tends to be proportional to size of corresponding memory allocation. In this paper, we propose the Application-Based Coarse-Grained Incremental Checkpointing (ACCK) that leverages the priori information of the memory allocation to release the memory monitoring granularity in an incremental and appropriate way. This provides better opportunities for balancing the tradeoff between monitoring and copying overhead. ACCK is also assisted by hugepage to alleviate the TLB overhead. Our experiment shows that ACCK presents 2.56x performance improvement over the baseline mechanism.

Hybrid sensor networks (HSNs) comprise of mobile and static sensor nodes setup for purpose of collaboratively performing tasks like sensing a phenomenon or monitoring a region. In this paper, we present target interception as a novel application using mobile sensor nodes as executor. Static sensor nodes sense, compute and communicate with each other for navigation. Mobile nodes are guided to intercept target by the static nodes nearby. Our approach does not require any prior maps of the environment thus, cutting down the cost of the overall energy consumption. As to multi-targets multi-mobile nodes case, we present a PMB algorithm for task assignment. Simulation results have verified the feasibility and effectiveness of our approach proposed.

Free-space optical (FSO) links offer gigabit per second data rates and low system complexity, but suffer from atmospheric loss due to fog and scintillation. Radio-frequency (RF) links have lower data rates, but are relatively insensitive to weather. Hybrid FSO/RF links combine the advantages of both links. Currently, selection or "hard-switching" is performed between FSO or RF links depending on feedback from the receiver. This technique is inefficient since only one medium is used at a time. In this paper, we develop a "soft-switching" scheme for hybrid FSO/RF links using short-length Raptor codes. Raptor encoded packets are sent simultaneously on both links and the code adapts to the conditions on either link with very limited feedback. A set of short-length Raptor codes (k = 16 to 1024) are presented which are amenable to highspeed implementation. A practical Raptor encoder and decoder are implemented in an FPGA and shown to support a 714 Mbps data rate with a 97 mW power consumption and 26360 gate circuit scale. The performance of the switching algorithms is simulated in a realistic channel model based on climate data. For a 1 Gbps FSO link combined with a 96 Mbps WiMAX RF link, an average rate of over 472 Mbps is achieved using the implemented Raptor code while hard-switching techniques achieved 112 Mbps on average.

Wireless sensor networks may be destroyed by targets in field surveillance. Self-protection technology focuses on using sensor nodes to protect themselves so as to resist attacks. Selecting protecting nodes has been proved to be a NP-complete problem. In this paper, we propose a new distributed layered negotiation based approximation algorithm to find a protecting set using local topology information. Experimental result manifests the feasibility and efficiency of our algorithms proposed.

Nonvolatile memory (e.g., Phase Change Memory) blurs the boundary between memory and storage and it could greatly facilitate the construction of in-memory durable data structures. Data structures can be processed and stored directly in NVRAM. To maintain the consistency of persistent data, logging is a widely adopted mechanism. However, logging introduces write-twice overhead. This paper introduces an optimized write-combined logging to reduce the writes to NVRAM log. By leveraging the fast-read and byte-addressable features of NVRAM, we can perform a read-and-compare operation before writes and thus issue writes in a finer-grained way. We tested our system on the benchmark suit STAMP which contains real-world applications. Experiment results show that our system can reduce the writes to NVRAM by 33%–34%, which can help extend the lifetime of NVRAM and improve performance. Averagely our system can improve performance by 7%–11%.

Dangling pointer error is pervasive in C/C++ programs and it is very hard to detect. This paper introduces an efficient detector to detect dangling pointer error in C/C++ programs. By selectively leave some memory accesses unmonitored, our method could reduce the memory monitoring overhead and thus achieves better performance over previous methods. Experiments show that our method could achieve an average speed up of 9% over previous compiler instrumentation based method and more than 50% over previous page protection based method.

With the development of the electricity market, competition has been introduced in the generation side. It is the overall development trend of the electricity market reformulation to optimize the allocation of different resources through bidding. Therefore, it is significant to research the bidding strategies of the generation companies and the large consumers. This paper reviews the existing research methods of bidding strategy. According to the different market mechanisms, the market participators will choose different bidding strategies based on their own cases. We analyze the applicability of bidding strategies under the different conditions, and give suggestions on how to select bidding strategy for the different market participators under different conditions.

Indoor localization based on WiFi signal strength fingerprinting techniques have been attracting many research efforts in past decades. Many localization algorithms have been proposed in order to achieve higher localization accuracy. In this paper, we investigate Bayes learning algorithms and some common-used machine learning algorithms. We identify a general problem of Zero Probability (ZP) which may cause significant decrease of accuracy. In order to solve this problem, we propose an Improved Naive Bayes Simple learning algorithm, namely INBS, based on our data set characteristic. INBS is applicable even though Zero Probability problem occurs. We design experiments based on off-the-shelf WiFi devices, mobile phones and well-known machine learning tool Weka. Our experiments are conducted on a floor covering 560m 2 in a campus building and a laboratory covering 78m 2 . Experiment results show that INBS outperforms traditional Naive Bayes and k-Nearest Neighbors (k-NN) algorithms and two common-used machine learning algorithms in terms of accuracy.

The network lifetime is a fundamental criterion for evaluating WSNs. Receiving and sending data packets consume energy so judicious routing strategies can effectively extend operational time. The ant colony optimization algorithm, known as ACO, is a probabilistic technique for solving computational problems. In this paper, an ACO-based routing algorithm called PACO is proposed. We take three factors into consideration. First of all, the hops are to be minimized. Additionally, energy distance is defined and needs minimizing. We also define the popularity of the sensors given the necessity to avoid those nodes that are used too often while routing. The definition of the lifetime and energy model is discussed as well. By conducting the simulation, it is proved that PACO outperforms other ACO routing algorithms, indicating that PACO is a promising routing algorithm for prolonging the lifetime of WSNs.

Antimony ions were implanted into ZnO films grown on c-plane sapphire by pulsed-laser deposition. Raman scattering modes of the Sb-implanted samples were found to be influenced by the implantation dose. A characteristic peak at 576 cm − 1 was observed with an asymmetric shape due to ion damage to the lattice of the implanted ZnO films. When the implant dose was low, the height of the peak was reduced by rapid thermal annealing at 400–600 °C and the symmetry of the spectra was recovered. However, when the Sb dose exceeded 1 × 10 15 cm − 2 , the peak maintained unchanged after rapid thermal annealing at temperatures up to 600 °C. A broad and low Raman peak was observed at 437 cm − 1 , which is related to the surface damage caused by the energetic ion bombarding. Photoluminescence measurement showed a decrease of the bandedge emission at 3.36 eV, a clear effect of defects induced by the implantation, and confirmed partial recovery of the crystal by rapid annealing.