DECENTRALIZED AND SCALABLE RESOURCE MANAGEMENT FOR DESKTOP GRIDS

The recent growth of the Internet and the CPU power of personal computers and workstations enables desktop grid computing to achieve tremendous computing power with low cost, through opportunistic sharing of resources. However, traditional server-client Grid architectures have inherent problems in robustness, reliability and scalability. Researchers have therefore recently turned to Peer-to-Peer (P2P) algorithms in an attempt to address these issues. I have designed and evaluated a set of protocols that implement a scalable P2P desktop grid computing system for executing Grid applications on widely distributed sets of resources. Such infrastructure must be decentralized, robust, highly available and scalable, while effectively mapping application instances to available resources throughout the system (called matchmaking). First of all, I address the problem of efficient matchmaking of jobs to available system resources by employing customized Content-Addressable Network (CAN) where each resource type corresponds to a distinct dimension. With this approach, incoming jobs are matched with system nodes through proximity in an N-dimensional resource space. Second, I provide comprehensive load balancing mechanisms that can greatly improve overall system throughput and response time without using any centralized control or information about the system. Finally, to remove any hot spots in the system where a small number of nodes are processing a lot of system maintenance work, I have designed a set of optimizations to minimize overall system overheads and distribute them fairly among available system nodes. My ultimate goal is to ensure that no node in the system becomes much more heavily loaded than others, either because of executing jobs or from system maintenance tasks. This is because every node in our system is a peer, so that no node is acting as a pure server or a pure client. Throughout extensive experimental results, I show that the resulting P2P desktop grid computing system is scalable and effective so that it can efficiently match any type of resource requirements for jobs simultaneously, while balancing load among multiple candidate nodes

Achieving Fairness-aware Two-level Scheduling for Heterogeneous Distributed Systems

In a heterogeneous distributed system composed of various types of computing platforms such as supercomputers, grids, and clouds, a two-level scheduling approach can be used to effectively distribute resources of the platforms to users in the first-level, and map tasks of the users in nodes for each platform in the second-level for executing many-task applications. When scheduling heterogeneous resources, service providers of the system should consider the fairness among multiple users as well as the system efficiency. However, the fairness cannot be achieved by simply distributing an equal amount of resources from each platform to every user. In this paper, we investigate how to address the fairness issue among multiple users in a heterogeneous distributed system. We present three first-level resource allocation policies of a provider affinity first policy, an application affinity first policy, and a platform affinity based round-robin policy, and two second-level task mapping policies of a most affected first policy and a co-runner affinity based round-robin policy. Using trace-based simulations, we evaluate the performance of various combinations of the first and second level scheduling policies. Our extensive simulation results demonstrate that the first-level policy plays a crucial role to achieve relatively good fairness

Matching Jobs to Resources in Distributed Desktop Grid Environments

Desktop grids use opportunistic sharing to exploit large collections of personal computers and workstations across the Internet and can achieve tremendous computing power with low cost. However, current systems are typically based on a traditional client-server architecture, which has inherent shortcomings with respect to robustness, reliability and scalability. In this paper, we propose a decentralized, robust, highly available, and scalable infrastructure to match incoming jobs to available resources. The key idea behind our proposed system is to leverage information provided by an underlying peer-to-peer system to create a hierarchical Rendezvous Node Tree, which performs the matching efficiently. Our experimental results obtained via simulation show that we can effectively match jobs with varying levels of resource constraints to available nodes and maintain good load balance in a fully decentralized heterogeneous computational environment

Efficient and facile delivery of gold nanoparticles in vivo using dissolvable microneedles for contrast-enhanced optical coherence tomography

Obtaining sufficient contrast is an indispensable requirement for detecting early stage cancer using optical coherence tomography (OCT), an emerging diagnostic tool that detects abnormal lesions with micrometer resolutions in real time. PEGylated gold nanoparticles (Au NPs; 87 nm in diameter) were formulated in aqueous dissolvable microneedles (dMNs; 200 μm height) for efficient, precisely controlled, and convenient delivery of Au NPs into hamster oral tissue in vivo. The Au NPs were then further briefly dissipated by ultrasound (US). The results showed 33% and 20% increase in average optical scattering intensity (contrast level) in dysplastic and normal tissues, respectively, and pinpointed pathological structures of early stage oral cancer were also identified by the highly convenient and efficient administration of Au NPs in a novel delivery platform

Using Content-Addressable Networks for Load Balancing in Desktop Grids

Desktop grids combine Peer-to-Peer and Grid computing techniques to improve the robustness, reliability and scalability of job execution infrastructures. However, efficiently matching incoming jobs to available system resources and achieving good load balance in a fully decentralized and heterogeneous computing environment is a challenging problem. In this paper, we extend our prior work with a new decentralized algorithm for maintaining approximate global load information, and a job pushing mechanism that uses the global information to push jobs towards underutilized portions of the system. The resulting system more effectively balances load and improves overall system throughput. Through a comparative analysis of experimental results across different system configurations and job profiles, performed via simulation, we show that our system can reliably execute Grid applications on a distributed set of resources both with low cost and with good load balance

High frequencies of Y-chromosome haplogroup O2b-SRY465 lineages in Korea: a genetic perspective on the peopling of Korea

<p>Abstract</p> <p>Background</p> <p>Koreans are generally considered a Northeast Asian group, thought to be related to Altaic-language-speaking populations. However, recent findings have indicated that the peopling of Korea might have been more complex, involving dual origins from both southern and northern parts of East Asia. To understand the male lineage history of Korea, more data from informative genetic markers from Korea and its surrounding regions are necessary. In this study, 25 Y-chromosome single nucleotide polymorphism markers and 17 Y-chromosome short tandem repeat (Y-STR) loci were genotyped in 1,108 males from several populations in East Asia.</p> <p>Results</p> <p>In general, we found East Asian populations to be characterized by male haplogroup homogeneity, showing major Y-chromosomal expansions of haplogroup O-M175 lineages. Interestingly, a high frequency (31.4%) of haplogroup O2b-SRY465 (and its sublineage) is characteristic of male Koreans, whereas the haplogroup distribution elsewhere in East Asian populations is patchy. The ages of the haplogroup O2b-SRY465 lineages (~9,900 years) and the pattern of variation within the lineages suggested an ancient origin in a nearby part of northeastern Asia, followed by an expansion in the vicinity of the Korean Peninsula. In addition, the coalescence time (~4,400 years) for the age of haplogroup O2b1-47z, and its Y-STR diversity, suggest that this lineage probably originated in Korea. Further studies with sufficiently large sample sizes to cover the vast East Asian region and using genomewide genotyping should provide further insights.</p> <p>Conclusions</p> <p>These findings are consistent with linguistic, archaeological and historical evidence, which suggest that the direct ancestors of Koreans were proto-Koreans who inhabited the northeastern region of China and the Korean Peninsula during the Neolithic (8,000-1,000 BC) and Bronze (1,500-400 BC) Ages.</p

Crystal Structures of the Tetratricopeptide Repeat Domains of Kinesin Light Chains: Insight into Cargo Recognition Mechanisms

Kinesin-1 transports various cargos along the axon by interacting with the cargos through its light chain subunit. Kinesin light chains (KLC) utilize its tetratricopeptide repeat (TPR) domain to interact with over 10 different cargos. Despite a high sequence identity between their TPR domains (87%), KLC1 and KLC2 isoforms exhibit differential binding properties towards some cargos. We determined the structures of human KLC1 and KLC2 tetratricopeptide repeat (TPR) domains using X-ray crystallography and investigated the different mechanisms by which KLCs interact with their cargos. Using isothermal titration calorimetry, we attributed the specific interaction between KLC1 and JNK-interacting protein 1 (JIP1) cargo to residue N343 in the fourth TRP repeat. Structurally, the N343 residue is adjacent to other asparagines and lysines, creating a positively charged polar patch within the groove of the TPR domain. Whereas, KLC2 with the corresponding residue S328 did not interact with JIP1. Based on these finding, we propose that N343 of KLC1 can form “a carboxylate clamp” with its neighboring asparagine to interact with JIP1, similar to that of HSP70/HSP90 organizing protein-1's (HOP1) interaction with heat shock proteins. For the binding of cargos shared by KLC1 and KLC2, we propose a different site located within the groove but not involving N343. We further propose a third binding site on KLC1 which involves a stretch of polar residues along the inter-TPR loops that may form a network of hydrogen bonds to JIP3 and JIP4. Together, these results provide structural insights into possible mechanisms of interaction between KLC TPR domains and various cargo proteins

A Case of Amblyomma testudinarium Tick Bite in a Korean Woman

A case of tick bite was found in the inguinal region of a 74-year-old Korean woman. She was attacked by the tick while working in her vegetable garden in the vicinity of mountain located in Suncheon City, the southern coastal area of the Korean Peninsula. On admission she complained of mild discomfort and itching around the bite area. The causative tick was 23 mm long and had slender pedipalps. The scutum was quite ornate and had eyes at the edge. The genital aperture was located anterior to the level of the coxa II. The spiracular plate was comma-shaped and the anus was surrounded posteriorly by the anal groove. The coxa I had subequal 2 spurs; the external one slightly larger. The spur of coxa IV was slightly longer than those of coxae II and III. The tarsus IV had 2 distinct subapical ventral spurs. It was identified as the fully engorged adult female of Amblyomma testudinarium. This is the first human case of Amblyomma bite in Korea

Soluble neprilysin and long-term clinical outcomes in patients with coronary artery disease undergoing percutaneous coronary intervention: a retrospective cohort study

Background: Neprilysin has an essential role in regulating fluid balance and vascular resistance, and neprilysin inhibitors have shown beneficial effects in patients with heart failure. However, the potential predictive value of neprilysin levels as a biomarker for cardiovascular risk remains unclear. The aim of this study was to assess the prognostic value of soluble neprilysin (sNEP) levels in patients with ischemic heart disease. Methods: Neprilysin levels were measured in 694 consecutive patients with coronary artery disease (CAD) undergoing percutaneous coronary intervention (PCI). These patients were classified into two groups according to their serum levels of neprilysin and categorized into the lower neprilysin group (n = 348) and the higher neprilysin group (n = 346). The primary clinical endpoint was all-cause mortality, and the secondary endpoint was a composite of major adverse cardiac events (MACE). Results: The median sNEP level was 76.0 pg/ml. The median sNEP levels were higher in patients with left ventricular ejection fraction (LVEF) ≥40% (77.6 pg/ml, interquartile range 46.6–141.3) than in those with LVEF \u3c 40% (70.0 pg/ml, interquartile range 47.1–100.6; P = 0.032). Among all patients, each clinical outcome and MACE did not differ significantly according to the groups divided into median, tertile, or quartile of sNEP levels during a median follow-up of 28.4 months. We did not find a significant relationship between sNEP levels and clinical outcomes in multivariate Cox regression analysis. Among patients with LVEF \u3c 40%, an increased sNEP level was associated with a higher rate of all-cause death (adjusted hazard ratio 2.630, 95% confidence interval 1.049–6.595, P = 0.039). Conclusion: Serum sNEP levels are not associated with long-term mortality or cardiovascular outcomes after PCI in patients with CAD. In the LVEF \u3c 40% group, increased sNEP levels may be associated with a higher risk of all-cause death

Nonimmunity against hepatitis B virus infection in patients newly diagnosed with inflammatory bowel disease

Background/AimsThis study aimed to elucidate the prevalence of hepatitis B virus (HBV) serologic markers in Korean patients newly diagnosed with, but not yet treated for inflammatory bowel disease (IBD).MethodsWe prospectively enrolled 210 patients newly diagnosed with IBD (109 with ulcerative colitis and 101 with Crohn's disease). Hepatitis B surface antigen (HBsAg), hepatitis B surface antibody (anti-HBs), and hepatitis B core antibody (anti-HBc) levels were measured and compared with those of 1,100 sex- and age-matched controls.ResultsThe prevalence of chronic HBV infection (positive HBsAg, positive anti-HBc, and negative anti-HBs results) and past infection (negative HBsAg, positive anti-HBc, and positive or negative anti-HBs results) were not significantly different between the patients and controls (chronic HBV infection: IBD, 3.8% vs. control, 4.9%, P=0.596; past infection: IBD, 26.2% vs. control, 28.8%, P=0.625). The patients with IBD aged <20 years were at a higher susceptibility risk (nonimmune) for HBV infection than the controls (IBD, 41.5% vs. control, 22.4%; P=0.018). In the multivariate analysis, an age of <20 years (P=0.024) and symptom duration of ≥12 months before diagnosis (P=0.027) were identified as independent risk factors for nonimmunity against HBV infection.ConclusionsThe patients newly diagnosed with IBD were susceptible to HBV infection. The frequency of nonimmunity was high, especially in the patients aged <20 years and those with a longer duration of symptoms before diagnosis. Therefore, it is necessary to screen for HBV serologic markers and generate a detailed vaccination plan for patients newly diagnosed with IBD