Exploration of Fine-Grained Parallelism for Load Balancing Eager K-truss on GPU and CPU

In this work we present a performance exploration on Eager K-truss, a linear-algebraic formulation of the K-truss graph algorithm. We address performance issues related to load imbalance of parallel tasks in symmetric, triangular graphs by presenting a fine-grained parallel approach to executing the support computation. This approach also increases available parallelism, making it amenable to GPU execution. We demonstrate our fine-grained parallel approach using implementations in Kokkos and evaluate them on an Intel Skylake CPU and an Nvidia Tesla V100 GPU. Overall, we observe between a 1.261. 48x improvement on the CPU and a 9.97-16.92x improvement on the GPU due to our fine-grained parallel formulation.Comment: 2019 IEEE High Performance Extreme Computing Conference (HPEC

Inhaled corticosteroid use and risks of lung cancer and laryngeal cancer

SummaryBackgroundChronic inflammation has been implicated in the pathogenesis of several cancers, including lung and laryngeal cancer. The objective of the study is to elucidate the association between ICS use and diagnosis of lung and laryngeal cancer.MethodsA nested case–control study based on the Korean national claims database included new adult users of inhaled medications between January 1, 2007, and December 31, 2010. Patients diagnosed with lung cancer or laryngeal cancer after enrollment were identified as cases and up to five control individuals matched for age, sex, diagnosis of asthma or COPD, Charlson Comorbidity Index scores, number of health care visits, and initiation date were selected.ResultsFrom the 792,687 eligible cohort, 9177 individuals diagnosed with lung cancer were matched with 37,048 controls. Additionally, 408 laryngeal cancer patients and 1651 controls were matched. ICS use was associated with a decreased rate of lung cancer diagnosis [adjusted odds ratio (aOR), 0.79; 95% confidence interval (CI), 0.69–0.90]. The inverse association between ICS use and lung cancer risk was dose dependent (P < 0.0001 for the trend). However, no reduction in the risk of laryngeal cancer among ICS users was identified (aOR, 1.06; 95% CI, 0.62–1.18).ConclusionThe use of ICS is associated with a reduced risk of lung cancer but not of laryngeal cancer

Assessment of foodservice quality and identification of improvement strategies using hospital foodservice quality model

The purposes of this study were to assess hospital foodservice quality and to identify causes of quality problems and improvement strategies. Based on the review of literature, hospital foodservice quality was defined and the Hospital Foodservice Quality model was presented. The study was conducted in two steps. In Step 1, nutritional standards specified on diet manuals and nutrients of planned menus, served meals, and consumed meals for regular, diabetic, and low-sodium diets were assessed in three general hospitals. Quality problems were found in all three hospitals since patients consumed less than their nutritional requirements. Considering the effects of four gaps in the Hospital Foodservice Quality model, Gaps 3 and 4 were selected as critical control points (CCPs) for hospital foodservice quality management. In Step 2, the causes of the gaps and improvement strategies at CCPs were labeled as "quality hazards" and "corrective actions", respectively and were identified using a case study. At Gap 3, inaccurate forecasting and a lack of control during production were identified as quality hazards and corrective actions proposed were establishing an accurate forecasting system, improving standardized recipes, emphasizing the use of standardized recipes, and conducting employee training. At Gap 4, quality hazards were menus of low preferences, inconsistency of menu quality, a lack of menu variety, improper food temperatures, and patients' lack of understanding of their nutritional requirements. To reduce Gap 4, the dietary departments should conduct patient surveys on menu preferences on a regular basis, develop new menus, especially for therapeutic diets, maintain food temperatures during distribution, provide more choices, conduct meal rounds, and provide nutrition education and counseling. The Hospital Foodservice Quality Model was a useful tool for identifying causes of the foodservice quality problems and improvement strategies from a holistic point of view

Alcohol use behaviors and risk of metabolic syndrome in South Korean middle-aged men

<p>Abstract</p> <p>Background</p> <p>It is thought that small volumes of alcohol may have positive effects on health. However, excessive drinking results in serious health problems. An accurate method to determine individual alcohol use behaviors are needed to assess objectively the extent to which drinking affects health. This study investigated the association between risk of metabolic syndrome (MetS) and alcohol use behaviors in middle-aged South Korean men using the Alcohol Use Disorders Identification Test.</p> <p>Methods</p> <p>This study used data from the South Korea National Health and Nutrition Examination (KNHANES) IV (2008), which extracted the standard survey household by using the proportional systematic sampling method. Data of 714 participants from KNHANES IV, 2008 were analyzed using Surveyfreq and Surveylogistic regression to investigate the association between MetS and alcohol use behaviors in middle-aged South Korean men.</p> <p>Results</p> <p>After adjustment for education, smoking, and physical activity, alcohol use behaviors were significantly associated with an increased risk of hypertension [odds ratio (OR) = 2.54, 95% confidence interval (CI) = 1.5-4.06 in the hazardous group; OR = 2.99, 95% CI = 1.84-4.92 in the problem group]; impaired fasting glucose (OR = 2.15, 95% CI = 1.16-3.99 in the hazardous group; OR = 2.48, 95% CI = 1.42-4.33 in the problem group); dyslipidemia (OR = 2.19, 95% CI = 1.38-3.47 in the problem group); abdominal obesity (OR = 1.93, 95% CI = 1.17-3.19 in the hazardous group; OR = 1.85, 95% CI = 1.17-2.92 in the problem group); and MetS (OR = 2.16, 95% CI = 1.24-3.77 in the hazardous group; OR = 2.54, 95% CI = 1.41-4.58 in problem group).</p> <p>Conclusions</p> <p>This study found that excessive alcohol use behaviors increased the risk of hypertension, diabetes, dyslipidemia, abdominal obesity, and MetS. Considering the rising rate of alcohol consumption and heavy drinking at single sittings, a culture of less risky alcohol consumption must be established to promote health among middle-aged men.</p

Creation of Dimeric Perkinsus Marinus Creatine Kinase Through Site-Directed Mutagenesis: Insight into Phosphagen Kinase Quaternary Structure Evolution

Cytosolic creatine kinases (CK) play a central role in buffering ATP levels and are obligate dimers; a single subunit cannot function without the presence of the other. However, a recent discovery revealed that novel CKs in Perkinsus marinus (PmCK), a parasitic protozoan, comprise only a single subunit yet remain completely active. Amino acid sequence alignment indicated that PmCKs are missing some key residues involved in dimerization as identified in dimeric CKs; hence they exist as monomers. However, the monomeric state of PmCK is evolutionarily in query: whether it lost the ability to dimerize or is only a few mutations away from becoming a dimer. To understand how the change in key residues affects the quaternary structure of PmCK, site-directed mutagenesis was used to introduce the key residues (G83D, F178R, and G179D) into PmCK. Five mutants were made: G83D, F178R, D179G, G83D/F178R (double), and G83D/F178R/D179G (triple). Size-exclusion chromatography showed that the Double and Triple mutants formed equilibrium mixtures of monomer and dimer (~45 and ~90 kDa, respectively), with the monomeric form being predominant. NADH-coupled enzyme assay indicated that both mutants showed significant decreases in catalytic efficiency (~20 and 65-fold decrease, compared to that of the WT). It is uncertain why the dimers showed decrease in activity; hence it is difficult to support or refute whether PmCK might have escaped from its dimeric precursor or never acquired the additional ‘background/hidden’ mutation needed to become a functional dimer

Finite element modeling of electromagnetic radiation and induced heat transfer in the human body

textThis dissertation develops adaptive hp-Finite Element (FE) technology and a parallel sparse direct solver enabling the accurate modeling of the absorption of Electro-Magnetic (EM) energy in the human head. With a large and growing number of cell phone users, the adverse health effects of EM fields have raised public concerns. Most research that attempts to explain the relationship between exposure to EM fields and its harmful effects on the human body identifies temperature changes due to the EM energy as the dominant source of possible harm. The research presented here focuses on determining the temperature distribution within the human body exposed to EM fields with an emphasis on the human head. Major challenges in accurately determining the temperature changes lie in the dependence of EM material properties on the temperature. This leads to a formulation that couples the BioHeat Transfer (BHT) and Maxwell equations. The mathematical model is formed by the time-harmonic Maxwell equations weakly coupled with the transient BHT equation. This choice of equations reflects the relevant time scales. With a mobile device operating at a single frequency, EM fields arrive at a steady-state in the micro-second range. The heat sources induced by EM fields produce a transient temperature field converging to a steady-state distribution on a time scale ranging from seconds to minutes; this necessitates the transient formulation. Since the EM material properties depend upon the temperature, the equations are fully coupled; however, the coupling is realized weakly due to the different time scales for Maxwell and BHT equations. The BHT equation is discretized in time with a time step reflecting the thermal scales. After multiple time steps, the temperature field is used to determine the EM material properties and the time-harmonic Maxwell equations are solved. The resulting heat sources are recalculated and the process continued. Due to the weak coupling of the problems, the corresponding numerical models are established separately. The BHT equation is discretized with H¹ conforming elements, and Maxwell equations are discretized with H(curl) conforming elements. The complexity of the human head geometry naturally leads to the use of tetrahedral elements, which are commonly employed by unstructured mesh generators. The EM domain, including the head and a radiating source, is terminated by a Perfectly Matched Layer (PML), which is discretized with prismatic elements. The use of high order elements of different shapes and discretization types has motivated the development of a general 3D hp-FE code. In this work, we present new generic data structures and algorithms to perform adaptive local refinements on a hybrid mesh composed of different shaped elements. A variety of isotropic and anisotropic refinements that preserve conformity of discretization are designed. The refinement algorithms support one- irregular meshes with the constrained approximation technique. The algorithms are experimentally proven to be deadlock free. A second contribution of this dissertation lies with a new parallel sparse direct solver that targets linear systems arising from hp-FE methods. The new solver interfaces to the hierarchy of a locally refined mesh to build an elimination ordering for the factorization that reflects the h-refinements. By following mesh refinements, not only the computation of element matrices but also their factorization is restricted to new elements and their ancestors. The solver is parallelized by exploiting two-level task parallelism: tasks are first generated from a parallel post-order tree traversal on the assembly tree; next, those tasks are further refined by using algorithms-by-blocks to gain fine-grained parallelism. The resulting fine-grained tasks are asynchronously executed after their dependencies are analyzed. This approach effectively reduces scheduling overhead and increases flexibility to handle irregular tasks. The solver outperforms the conventional general sparse direct solver for a class of problems formulated by high order FEs. Finally, numerical results for a 3D coupled BHT with Maxwell equations are presented. The solutions of this Maxwell code have been verified using the analytic Mie series solutions. Starting with simple spherical geometry, parametric studies are conducted on realistic head models for a typical frequency band (900 MHz) of mobile phones.Engineering Mechanic

Homogeneous Solution for SW Lacertae

We have analyzed collected photoelectric light curves for light variations of SW Lac. The method of Fourier analysis was adopted to quantify the light variation from season to season. We found the linear relation between the Fourier coefficient, B1 and the magnitude difference between two maxima. The total light of the system has been decreased as much as 0m.04 during approximately 20 years time interval. Photoelectric parameters including spot parameters for all light curves were obtained by the method of the Wilson and Devinney differential correction in order to secure the variations of parameters from season to season. SW Lac, not like RS CVn type stars, required to adjust all parameters as well as spot parameters for a reasonable fit to the observations of each epoch. A surface temperature of cooler star is one of the most sensitive parameters to affect a shape of light curve of SW Lac. We conclude that the shape of light curve of SW Lac varies even during one season as well as season to season. The light curve is mainly caused by inhomogeneous surface temperature due to strong chromospheric activity of the system

Changes in Fan Energy Consumption According to Filters Installed in Residential Heat Recovery Ventilators in Korea

In recent years, because of outdoor ultrafine particles, residential heat recovery ventilators (HRVs) have been used with high efficiency filters by residents in Korea. However, as pre-filters are primarily used in residential HRVs, when a high-efficiency particulate air (HEPA) filter is installed, the filter pressure drop increases, reducing the airflow rate, which requires the fan to draw more power to maintain the airflow rate. Therefore, in this study, the change in power usage of HRVs installed in residential apartments in Korea with various air volumes and filters were analyzed. The results show that HEPA filters consumed 13.5–17.5% (16.1% on an average), 11.8–16.0% (13.8% on an average), and 16.8–41.3% (30.1% on an average) more power at 0.5, 1.0, and 1.5 air changes/h, respectively, than the pre-filter. These results indicate that unexpected power consumption increase could be caused if a pre-filter is replaced with a HEPA filter in residential small air-volume HRVs. This may lead to noise or failure due to fan overload. Thus, it is necessary to operate residential HRVs at the optimum air volume according to the fan performance