736 research outputs found

    Resilient-ODMRP: Resilient On-Demand Multicast Routing Protocol

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    (On-Demand Multicast Routing Protocol) [5] [7] [1] is a popular multicast protocol for wireless ad hoc networks. The strengths of ODMRP are simplicity, high packet delivery ratio, and non-dependency on a specific unicast protocol. ODMRP floods a route request over the entire network to select a set of forwarding nodes for packet delivery. However, a single forwarding path is vulnerable to node failures, which are common due to the dynamic nature of mobile ad hoc networks. Furthermore, a set of misbehaving or malicious nodes can create network partitions and mount Denial-of-Service (DoS) attacks. We propose a ODMRP-based wireless multicast protocol named Resilient-ODMRP that offers more reliable forwarding paths in face of node and network failures. A subset of the nodes that are not on forwarding paths rebroadcast received packets to nodes in their neighborhoods to overcome perceived node failures. This rebroadcasting creates redundant forwarding paths to circumvent failed areas in the network. Each node makes this forwarding decision probabilistically. Our simulation results indicate that Resilient-ODMRP improves packet delivery ratio with minimal overheads, while retaining the original strengths of ODMRP

    Prediction-based virtual instance migration for balanced workload in the cloud datacenters

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    Datacenters in the cloud today provide virtualized resources of CPU, memory, disk, and networks so that millions of users can use the services at the same time in an efficient and scalable way. One of the major challenges in these datacenters is load balancing and shifting. As a huge number of requests are sent to a particular datacenter or a group of servers are asked to process more than their fair share, some of the servers are overloaded, slowed down, hot spots are created, and even hardware failures may occur. This unbalanced load in the end deteriorates the performance of the entire system easily. In this paper, we propose a load balancer that aims at alleviating hot spots and distributing the load from overloaded servers to underutilized servers. Our load balancer monitors the loads of the servers, detects indications of overloading, then migrates virtual instances from overloaded servers to target servers. We have implemented the load balancer in a real system using the Xen hypervisor. We have also conducted an event-driven simulation to evaluate the performance of our system on a large-scale. Our results indicate that our reactive-predictive load balancing algorithm helps balance load among servers in the cloud as much as the best-case scenario from the exhaustive search with much less overhead

    Dynamic Vehicular Route Guidance Using Traffic Prediction Information

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    We propose a dynamic vehicular routing algorithm with traffic prediction for improved routing performance. The primary idea of our algorithm is to use real-time as well as predictive traffic information provided by a central routing controller. In order to evaluate the performance, we develop a microtraffic simulator that provides road networks created from real maps, routing algorithms, and vehicles that travel from origins to destinations depending on traffic conditions. The performance is evaluated by newly defined metric that reveals travel time distributions more accurately than a commonly used metric of mean travel time. Our simulation results show that our dynamic routing algorithm with prediction outperforms both Static and Dynamic without prediction routing algorithms under various traffic conditions and road configurations. We also include traffic scenarios where not all vehicles comply with our dynamic routing with prediction strategy, and the results suggest that more than half the benefit of the new routing algorithm is realized even when only 30% of the vehicles comply

    99mTc-MAA accumulation within tumor in preoperative lung perfusion SPECT/CT associated with occult lymph node metastasis in patients with clinically N0 non-small cell lung cancer

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    Background 99mTc-MAA accumulation within the tumor representing pulmonary arterial perfusion, which is variable and may have a clinical significance. We evaluated the prognostic significance of 99mTc-MAA distribution within the tumor in non-small cell lung cancer (NSCLC) patients in terms of detecting occult nodal metastasis and lymphovascular invasion, as well as predicting the recurrence-free survival (RFS). Methods Two hundred thirty-nine NSCLC patients with clinical N0 status who underwent preoperative lung perfusion SPECT/CT were retrospectively evaluated and classified according to the visual grading of 99mTc-MAA accumulation in the tumor. Visual grade was compared with the quantitative parameter, standardized tumor to lung ratio (TLR). The predictive value of 99mTc-MAA accumulation with occult nodal metastasis, lymphovascular invasion, and RFS was assessed. Results Eighty-nine (37.2%) patients showed 99mTc-MAA accumulation and 150 (62.8%) patients showed the defect on 99mTc-MAA SPECT/CT. Among the accumulation group, 45 (50.5%) were classified as grade 1, 40 (44.9%) were grade 2, and 4 (4.5%) were grade 3. TLR gradually and significantly increased from grade 0 (0.009 ± 0.005) to grade 1 (0.021 ± 0.005, P < 0.05) and to grade 2–3 (0.033 ± 0.013, P < 0.05). The following factors were significant predictors for occult nodal metastasis in univariate analysis: central location, histology different from adenocarcinoma, tumor size greater than 3cm representing clinical T2 or higher, and the absence of 99mTc-MAA accumulation within the tumor. Defect in the lung perfusion SPECT/CT remained significant at the multivariate analysis (Odd ratio 3.25, 95%CI [1.24 to 8.48], p = 0.016). With a median follow-up of 31.5 months, the RFS was significantly shorter in the defect group (p = 0.008). Univariate analysis revealed that cell type of non-adenocarcinoma, clinical stage II-III, pathologic stage II-III, age greater than 65 years, and the 99mTc-MAA defect within tumor as significant predictors for shorter RFS. However, only the pathologic stage remained statistically significant, in multivariate analysis. Conclusion The absence of 99mTc-MAA accumulation within the tumor in preoperative lung perfusion SPECT/CT represents an independent risk factor for occult nodal metastasis and is relevant as a poor prognostic factor in clinically N0 NSCLC patients. 99mTc-MAA tumor distribution may serve as a new imaging biomarker reflecting tumor vasculatures and perfusion which can be associated with tumor biology and prognosis.This research was supported by the National Research Foundation of Korea (NRF) and funded by the Korean government (MSIT) (No.2020M3A9B6038086

    Breast Cancer Diagnosis Using a Microfluidic Multiplexed Immunohistochemistry Platform

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    BACKGROUND: Biomarkers play a key role in risk assessment, assessing treatment response, and detecting recurrence and the investigation of multiple biomarkers may also prove useful in accurate prediction and prognosis of cancers. Immunohistochemistry (IHC) has been a major diagnostic tool to identify therapeutic biomarkers and to subclassify breast cancer patients. However, there is no suitable IHC platform for multiplex assay toward personalized cancer therapy. Here, we report a microfluidics-based multiplexed IHC (MMIHC) platform that significantly improves IHC performance in reduction of time and tissue consumption, quantification, consistency, sensitivity, specificity and cost-effectiveness. METHODOLOGY/PRINCIPAL FINDINGS: By creating a simple and robust interface between the device and human breast tissue samples, we not only applied conventional thin-section tissues into on-chip without any additional modification process, but also attained perfect fluid control for various solutions, without any leakage, bubble formation, or cross-contamination. Four biomarkers, estrogen receptor (ER), human epidermal growth factor receptor 2 (HER2), progesterone receptor (PR) and Ki-67, were examined simultaneously on breast cancer cells and human breast cancer tissues. The MMIHC method improved immunoreaction, reducing time and reagent consumption. Moreover, it showed the availability of semi-quantitative analysis by comparing Western blot. Concordance study proved strong consensus between conventional whole-section analysis and MMIHC (n = 105, lowest Kendall's coefficient of concordance, 0.90). To demonstrate the suitability of MMIHC for scarce samples, it was also applied successfully to tissues from needle biopsies. CONCLUSIONS/SIGNIFICANCE: The microfluidic system, for the first time, was successfully applied to human clinical tissue samples and histopathological diagnosis was realized for breast cancers. Our results showing substantial agreement indicate that several cancer-related proteins can be simultaneously investigated on a single tumor section, giving clear advantages and technical advances over standard immunohistochemical method. This novel concept will enable histopathological diagnosis using numerous specific biomarkers at a time even for small-sized specimens, thus facilitating the individualization of cancer therapy

    X-ray Free Electron Laser Studies of Electron and Phonon Dynamics of Graphene Adsorbed on Copper

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    We report optical pumping and X-ray absorption spectroscopy experiments at the PAL free electron laser that directly probe the electron dynamics of a graphene monolayer adsorbed on copper in the femtosecond regime. By analyzing the results with ab-initio theory we infer that the excitation of graphene is dominated by indirect excitation from hot electron-hole pairs created in the copper by the optical laser pulse. However, once the excitation is created in graphene, its decay follows a similar path as in many previous studies of graphene adsorbed on semiconductors, i e. rapid excitation of SCOPS (Strongly Coupled Optical Phonons) and eventual thermalization. It is likely that the lifetime of the hot electron-hole pairs in copper governs the lifetime of the electronic excitation of the graphene.Comment: 22 pages, 8 Figures including Supplementary Materia

    Pengaruh Kualitas Produk, Harga, Dan Saluran Distribusi Terhadap Loyalitas Pelanggan Majalah Swa Melalui Variabel Kepuasan Pelanggan (Studi Kasus Pada Pelanggan Majalah Swa Di DKI Jakarta)

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    Customer loyalty is a goal that has to be achieved by a company. To be able to get loyal customers, SWA magazine needs to pay attention on the factors that influence customers\u27 loyalty. Moreover, business and economy themed magazines are mushrooming, leading to the opportunity for the readers to move from one magazine to another.This research aimed to ascertain the effect of product quality, price, and distribution channel on customer loyalty of SWA magazine in Jakarta through customer satisfaction variable both simultaneously and partially. The hypothesis was there was an effect of product quality, price, and distribution channel on customer loyalty of SWA magazine in Jakarta through customer satisfaction variable both simultaneously and partially. The type of this research was explanatory research with 97 respondents with multi stage sampling technique through questionnaire and interview. The data was analyzed using linear regression method with the assistance of SPSS 16.0.The result of this research showed that product quality, price and distribution channel variables had significant and positive effect partially on customer satisfaction. Product quality variable did not have partially significant effect on customer loyalty. Price and distribution channel variables had partially significant and positive effect on customer loyalty. Product quality and price variables had simultaneously positive and significant effect on customer satisfaction while distribution channel had simultaneously negative effect on customer satisfaction. Simultaneously, product quality, price, and distribution channel variables had positive effect and not significant effect on customer loyalty. Partially, customer satisfaction had positive and significant effect on customer loyalty.Based on the result of this research, a conclusion was drawn that customers\u27 perception on product quality, price, and distribution channel was good. Customers\u27 satisfaction and loyalty of SWA magazine were also good. The company was suggested to improving the product quality, adjusting the price and boosting the distribution channel of SWA magazine in accordance with customers\u27 needs and expectation, so that, customers can feel the satisfaction and decided to be loyal customers

    Direct and real-time observation of hole transport dynamics in anatase TiO2 using X-ray free-electron laser

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    Carrier dynamics affects photocatalytic systems, but direct and real-time observations in an element-specific and energy-level-specific manner are challenging. In this study, we demonstrate that the dynamics of photo-generated holes in metal oxides can be directly probed by using femtosecond X-ray absorption spectroscopy at an X-ray free-electron laser. We identify the energy level and life time of holes with a long life time (230 pico-seconds) in nano-crystal materials. We also observe that trapped holes show an energy distribution in the bandgap region with a formation time of 0.3 pico-seconds and a decay time of 8.0 pico-seconds at room temperature. We corroborate the dynamics of the electrons by using X-ray absorption spectroscopy at the metal L-edges in a consistent explanation with that of the holes

    The genome landscape of indigenous African cattle

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    Background: The history of African indigenous cattle and their adaptation to environmental and human selection pressure is at the root of their remarkable diversity. Characterization of this diversity is an essential step towards understanding the genomic basis of productivity and adaptation to survival under African farming systems. Results: We analyze patterns of African cattle genetic variation by sequencing 48 genomes from five indigenous populations and comparing them to the genomes of 53 commercial taurine breeds. We find the highest genetic diversity among African zebu and sanga cattle. Our search for genomic regions under selection reveals signatures of selection for environmental adaptive traits. In particular, we identify signatures of selection including genes and/ or pathways controlling anemia and feeding behavior in the trypanotolerant N’Dama, coat color and horn development in Ankole, and heat tolerance and tick resistance across African cattle especially in zebu breeds. Conclusions: Our findings unravel at the genome-wide level, the unique adaptive diversity of African cattle while emphasizing the opportunities for sustainable improvement of livestock productivity on the continent
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