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Jeong-Eun Park,1,2,&ast; Woo Cheol Kim,3,&ast; Sung Kyun Kim,4,5,&ast; Yeji Ahn,1,2 Sun Mok Ha,1,2 Gahee Kim,3 Seonmin Choi,3 Wan Su Yun,3 Tae Hoon Kong,1,2 Su Hoon Lee,1,2 Dong Jun Park,1,2 Jin Sil Choi,1,2 Jaehong Key,3 Young Joon Seo1,2 1Department of Otorhinolaryngology, Yonsei University Wonju College of Medicine, Wonju, 26426, South Korea; 2Research Institute of Hearing Enhancement, Yonsei University Wonju College of Medicine, Wonju, 26426, South Korea; 3Department of Biomedical Engineering, Yonsei University, Wonju, South Korea; 4Department of Otorhinolaryngology Head and Neck Surgery, Hallym University College of Medicine, Dongtan Sacred Heart Hospital, Hwaseong, South Korea; 5Laboratory of Brain & Cognitive Science for Convergence Medicine, Hallym University College of Medicine, Anyang, South Korea&ast;These authors contributed equally to this workCorrespondence: Young Joon Seo, Department of Otorhinolaryngology, Yonsei University Wonju College of Medicine, 20 Ilsan-ro, Wonju, 26426, South Korea, Tel +82 33 741 0644, Email okas2000@hanmail.net Jaehong Key, Department of Biomedical Engineering, Yonsei University, 1 Yonseidae-gil, Wonju, Gangwon-do, 26493, South Korea, Tel +82 33 760 2857, Email jkey@yonsei.ac.krBackground: Ototoxicity currently has no available treatment other than medication withdrawal as soon as toxicity is suspected. The human inner ear organs have little potential for regeneration; thus, ototoxicity-induced hair cell injury is deemed permanent. Dexamethasone (Dexa) is a synthetic steroid analog that has significant potential for otoprotection in the treatment of various inner ear diseases; however, its low absorption into the inner ear prevents significant recovery of function. Nanoparticles facilitate targeted drug delivery, stabilize drug release, and increase half-life of the drug.Methods: This study aimed to develop poly(lactic-co-glycolic acid) (PLGA) nanoparticles loaded superparamagnetic iron oxide nanoparticles (SPIONs) and Dexa (PSD-NPs) to control localized drug delivery by magnetic attraction in the treatment of ototoxicity-induced hearing loss. PSD-NPs and without SPIONs (PD-NPs) were prepared using a nanoprecipitation method.Results: Using an inner ear simulating system, we confirmed that PSD-NPs has an otoprotective effect in organotypic culture that is enhanced by magnetic attraction. PSD-NPs delivered via intrabullar injection in a magnetic field penetrated the inner ear and prevented hearing loss progression to a greater degree than equivalent doses of Dexa or PSD-NPs alone (day 28: ototoxic: 80.0 ± 0.0 dB; Dexa 100: 60.0 ± 15.5 dB; PSD 100: 50.0 ± 8.2 dB; PSD 100 with magnet: 22.5 ± 5.0 dB; P < 0.05). The protective effects were confirmed in various in vivo and in vitro models of ototoxicity.Conclusion: Our findings suggest that SPIONs with Dexa and magnetic field application prevent the progression of ototoxicity-induced hearing loss through anti-apoptotic mechanisms in the inner ear.Graphical Abstract: Keywords: superparamagnetic iron oxide nanoparticles, ototoxicity, hearing loss, magnetic attraction, dexamethasone

The thermal storage tank in a district heating system is a component that stores excess heat during normal operation and releases the stored heat to increase the efficiency of the system, when the heat source is stopped or additional demands occur. Recently, an obsolete thermal storage tank was dismantled for the first time since it began operation 30 years ago. In this work, the corrosion integrity of the obsolete thermal storage tank was evaluated by examining its appearance, thickness thinning, corrosion products, microstructure, and mechanical properties. Samples were taken at various locations (roof, shell, bottom) of the thermal storage tank, which enabled diagnosis of the respective environmental degradations. Severe corrosion was found in the roof edge plate due to corrosion under the insulation, and exhibited thinning exceeding ~49% of the designed thickness. In this location, the ferrite-pearlite band structure disappeared and deteriorated microstructures, such as decarburization and spheroidized pearlite, were measured, which resulted in a ~27% decrease in hardness. The inner surfaces of the bottom and shell plate were well covered with a magnetite film, and the degradation of the microstructure and mechanical properties showed a permissible limit in terms of ASTM A285/A516. In addition, no particular drop in hardness was found in the weld zone of each plate.

PurposeThe purpose of this paper is to examine the mediating relationship between organizational culture, informal learning and work engagement of older workers in a public organizational setting. More specifically, this study aimed to investigate if informal learning is a pivotal component connecting an organizational-level factor (culture) to work engagement, which, in turn, directly influences business performance in the workplace.Design/methodology/approachAfter a careful review of the selected and relevant literature, four hypotheses were developed to test the structural relationships between the selected variables.FindingsThe data analysis indicated that informal learning mediated the relationship between organizational culture and work engagement for older employees working in a public organizational setting.Practical implicationsThe findings from this study provide a solid justification for promoting informal learning in organizations to ensure knowledge transfer between younger and older generations while minimizing knowledge and financial loss for organizations.Originality/valueIn previous research, little emphasis has been placed on the impact of informal learning on work engagement. This study presents a valuable finding about the role of informal learning to facilitate work engagement for older workers.

This brief presents a 7-b 32-GS/s successive approximation register analog-to-digital converter (ADC) using a massive time-interleaving (TI) architecture. For low-skew multi-phase clocks, generation utilizing a delay-locked loop (DLL) phase-detector (PD) with a reduced offset is proposed to minimize skew between the clocks. Different clock path delays caused by distributed sub-ADCs over a large area in a massive TI-ADC are compensated for by multiplexing master clocks from the DLL. Offsets and skews in the sub-channels are calibrated on chip in the background via an additional dedicated sub-channel. A prototype chip was implemented in a 40-nm CMOS process with an active area of 0.36 mm2. The measured SFDR and SNDR of the prototype ADC at a conversion rate of 32 GS/s are 43.1 and 31.4 dB, respectively. The ADC, including the input buffers, consumes 125 mW under a single 0.9-V supply.

In this study, the cause of failure of a low-carbon steel pipe meeting standard KS D 3562 (ASTM A135), in a district heating system was investigated. After 6 years of operation, the pipe failed prematurely due to pitting corrosion, which occurred both inside and outside of the pipe. Pitting corrosion occurred more prominently outside the pipe than inside, where water quality is controlled. The analysis indicated that the pipe failure occurred due to aluminum inclusions and the presence of a pearlite inhomogeneous phase fraction. Crevice corrosion occurred in the vicinity around the aluminum inclusions, causing localized corrosion. In the large pearlite fraction region, cementite in the pearlite acted as a cathode to promote dissolution of surrounding ferrite. Therefore, in the groundwater environment outside of the pipe, localized corrosion occurred due to crevice corrosion by aluminum inclusions, and localized corrosion was accelerated by the large fraction of pearlite around the aluminum inclusions, leading to pipe failure.

Many research studies have been conducted on the corrosion inhibition performance of imidazole in acidic environments such as in the piping of a petrochemical plant. However, there has been no study on the effect of imidazole in alkaline conditions such as a local district water heating environment. Therefore, in this study, the effect of imidazole as a corrosion inhibitor on carbon steel weldment was investigated in alkaline district heating water. Inhibition efficiency and electrochemical properties were investigated by potentiodynamic polarization test and electrochemical impedance spectroscopy. As the concentration of imidazole increased up to 500 ppm, inhibition efficiency increased up to 91.7%. At 1000 ppm, inhibition efficiency decreased. Atomic force microscopy showed that surface coverage of imidazole at 1000 ppm is lower than that of imidazole at 500 ppm. X-ray photoelectron spectroscopy showed that with 500 ppm of imidazole, the amount of pyrrole type interaction is 4.8 times larger than pyridine type interaction. At 1000 ppm of imidazole, the amount of pyridine type interaction is 3.49 times larger than pyrrole type interaction. Depending on the concentration of imidazole, the ratio of interaction between carbon steel and imidazole affected inhibition efficiency.

Purpose The purpose of this paper is to examine the mediating role of the attitudes toward seeking professional psychological help between career adaptability and active job search behavior of older workers in South Korea. Design/methodology/approach From a review of related literature, six study hypotheses were developed to test the structural relationship between the variables. Findings This study identified that attitudes toward seeking professional psychological help mediated the relationship between career adaptability, the value of career coaching and active job search behavior. Practical implications A successful job search requires the use of substantial self-control and self-regulation skills, and there can be effective training in all these skills of self-disciplining when older workers can find a high level of value from career coaching programs. Originality/value Despite the growing popularity of career support programs, the quality of career coaching programs and participants’ perceived value toward them are critical to illicit positive outcomes of such programs. This study supports this premise by revealing a structural relationship between career adaptability, perceived value of career coaching, attitudes toward seeking professional career help and active job search behavior.

Stress corrosion cracking behavior of a copper pipe and its mechanism were investigated in a heating water supply system using both metallurgical and mechanical analyses. The X-ray diffraction and energy dispersive spectroscopy measurements showed that uniform cupric oxide and cuprous oxide were formed during service on the inside surface of the pipe, while malachite and cupric oxide were the main corrosion products on the outer surface of the pipe. Many corrosion pits were observed around the cracking areas on the outer surface by optical microscopy. Finite element modeling highlighted a region with large hoop stresses mainly brought about by the bolt load, where it became susceptible to stress corrosion cracking (SCC). The morphology of the fracture surface revealed an intergranular mode towards the outer surface but a mixed inter- and trans-granular mode near the inner surface. Based on the obtained results, a phenomenological 4-stage fracture process is proposed to describe the failure process of the copper pipe, in which the SCC initiated from the corrosion pits on the outer surface, propagated along the axial direction and penetrated towards the inner surface until final fracture.

Background and Objectives Mesenchymal stem cells (MSCs) are used to treat autoimmune or inflammatory diseases. Our aim was to determine the immunomodulatory mechanisms elicited by MSCs during inflammation. Methods and Results We cocultured MSCs with peripheral blood mononuclear cells for a mixed lymphocyte reaction or stimulated them by phytohemagglutinin. Morphological changes of MSCs and secretion of acetylcholine (ACh) from MSCs were measured. The effects of an ACh antagonist and ACh agonist on lymphocyte proliferation and proinflammatory-cytokine production were determined. The inflammatory milieu created by immune-cell activation caused MSCs to adopt a neuronlike phenotype and induced them to release ACh. Additionally, nicotinic acetylcholine receptors (nAChRs) were upregulated in activated peripheral blood mononuclear cells. We observed that ACh bound to nAChR on activated immune cells and led to the inhibition of lymphocyte proliferation and of proinflammatory-cytokine production. MSC-mediated immunosuppression through ACh activity was reversed by an ACh antagonist called α-bungarotoxin, and lymphocyte proliferation was inhibited by an ACh agonist, ACh chloride. Conclusions Our findings point to a novel immunomodulatory mechanism in which ACh secreted by MSCs under inflammatory conditions might modulate immune cells. This study may provide a novel method for the treatment of autoimmune diseases by means of MSCs.

Corrosion failure of materials often exposed to the corrosive environment in district heating systems is critical for operation and maintenance of the facility. It is important to establish a prevention method from an accurate prognosis on the cause of the corrosion failure. In this study, a failure analysis on the water wall boiler tube in a district heating system was carried out. The fracture occurred in an open window shape with a significant internal wall thinning that formed Na- and Fe-oxide by caustic corrosion. Tensile residual stress in the hoop direction developed inside the tube weakened the protective magnetite layer by accelerating the caustic corrosion, from which hydrogen atoms diffused into the alloy forming cavities or micro-voids at the grain boundaries. Furthermore, high temperature creep promoted the evolution of the cavities only inside the tube where there were tensile residual stresses. Consequently, a combination of hydrogen embrittlement and thermal creep initiated the cracks at the grain boundaries inside the tube, and the cracks propagated at the grain boundaries along the axial direction exhibiting an intergranular feature on the inside. Then, it gradually propagated toward the outside, finally exhibiting a transgranular fracture mode on the outside.

Various studies have been conducted to better understand the long-term corrosion mechanism for steels in a soil environment. Here, electrochemical acceleration methods present the most efficient way to simulate long-term corrosion. Among the various methods, galvanostatic testing allows for accelerating the surface corrosion reactions through controlling the impressed anodic current density. However, a large deviation from the equilibrium state can induce different corrosion mechanisms to those in actual service. Therefore, applying a suitable anodic current density is important for shortening the test times and maintaining the stable dissolution of steel. In this paper, to calibrate the anodic current density, galvanostatic tests were performed at four different levels of anodic current density and time to accelerate a one-year corrosion reaction of pipeline steel. To validate the appropriate anodic current density, analysis of the potential vs. time curves, thermodynamic analysis, and analysis of the specimen’s cross-sections and products were conducted using a validation algorithm. The results indicated that 0.96 mA/cm2 was the optimal impressed anodic current density in terms of a suitable polarized potential, uniform corrosion, and a valid corrosion product among the evaluated conditions.

Background Mesenchymal stem cells (MSCs) are pluripotent stromal cells that release extracellular vesicles (EVs). EVs contain various growth factors and antioxidants that can positively affect the surrounding cells. Nanoscale MSC-derived EVs, such as exosomes, have been developed as bio-stable nano-type materials. However, some issues, such as low yield and difficulty in quantification, limit their use. We hypothesized that enhancing exosome production using nanoparticles would stimulate the release of intracellular molecules. Results The aim of this study was to elucidate the molecular mechanisms of exosome generation by comparing the internalization of surface-modified, positively charged nanoparticles and exosome generation from MSCs. We determined that Rab7, a late endosome and auto-phagosome marker, was increased upon exosome expression and was associated with autophagosome formation. Conclusions It was concluded that the nanoparticles we developed were transported to the lysosome by clathrin-mediated endocytosis. additionally, entered nanoparticles stimulated that autophagy related factors to release exosome from the MSC. MSC-derived exosomes using nanoparticles may increase exosome yield and enable the discovery of nanoparticle-induced genetic factors.

To prevent a failure caused by stress corrosion cracking (SCC) of welded carbon steel pipe in district heating systems within service life, the effects of post weld heat treatment (PWHT) on the mechanical, electrochemical properties and resistance of SCC were investigated. As the result of normalized treatment, Vickers hardness, yield strength and tensile strength decreased, but ductility increased. Electrochemical properties were evaluated using potentiodynamic polarization tests and electrochemical impedance spectroscopy. Uniform corrosion was observed on all specimens, although the corrosion rate was slightly increased by PWHT. The resistance of SCC was evaluated using slow strain rate test under the accelerated corrosion condition. The resistance of SCC was increased by PWHT, especially by normalized treatment. If the reduced strength by PWHT satisfies the design stress, it is possible to decrease the probability of failure within service life in welded pipeline by normalized treatment.

A 6-bit 20 GS/s two-channel time-interleaved current-steering digital-to-analog converter (DAC) with compact full-binary sub-DACs is presented. Optimally adjusted transition timings between the input data and the interleaving clock minimize glitches by the time-interleaving switches and enhance the high-frequency linearity. In order to prevent static linearity degradation by the leakage current through the time-interleaving switches, the relationship between the output current and the leakage current is analyzed. The proposed DAC architecture and the pseudo-differential logic gates for the high-speed data interface reduce the circuit complexity as well as the power consumption. The prototype 6-bit 20 GS/s DAC, fabricated in a 65-nm CMOS process, achieves a spurious-free dynamic range of 35.1 dB up to the Nyquist input, and consumes 136 mW given a 1.2-V power supply.

This paper presents an investigation of a failure of the 316L stainless steel electric-heater tube in a heat-storage tank. Visual examination was performed to discover the characteristics of the fracture zone. The fracture appearance and the ingredient analysis of the filler material were examined using scanning electron microscopy and X-ray diffraction. Also, the region that is susceptible to corrosion was identified using an electrochemical method. From those investigations, the surface defects that were caused by improper die finish during drawing process acted as the initiation points of the corrosion process. The influent water changes the filler material from magnesia to magnesium hydroxide, which causes the volume expansion. The failure of tube occurred due to the combination of the pitting corrosion on the external surface and internal pressure from the volume expansion of the filler.

To restrain the failure of the plate heat exchanger (PHE) in customer boiler working fluid, the effect of crevice former type on the corrosion behavior of the 316L stainless steel plate was investigated using electrochemical methods and surface analyses in chloride-containing synthetic tap water (60 °C). The localized corrosion under metal–metal crevice condition was initiated more easily than that under the metal-gasket crevice condition due to the restricted mass transport at the gasket crevice mouth. However, the anodic current under the metal–metal crevice condition was lower than that under metal-gasket crevice condition at a higher anodic potential, indicating that that the metal dissolution under EPDM crevice would be higher than that under metal crevice under the accelerated corrosion condition. Because narrow crevice gap that was formed under gasket accelerated the anodic dissolution at the crevice mouth, the perforation tendency under metal-gasket crevice condition is much higher than that under metal–metal crevice condition. As a result, the crevice geometry, especially the crevice gap, mainly affected the corrosion behavior of PHE material.

External damage to buried pipelines is mainly caused by corrosive components in soil solution. The reality that numerous agents are present in the corrosive environment simultaneously makes it troublesome to study. To solve that issue, this study aims to determine the influence of the combination of pH, chloride, and sulfate by using a statistical method according to the design of experiment (DOE). Response surface methodology (RSM) using the Box–Behnken design (BBD) was selected and applied to the design matrix for those three factors. The input corrosion current density was evaluated by electrochemical tests under variable conditions given in the design matrix. The output of this method is an equation that calculates the corrosion current density as a function of pH, chloride, and sulfate concentration. The level of influence of each factor on the corrosion current density was investigated and response surface plots, contour plots of each factor were created in this study.

The effect of ultrasonic nanocrystal surface modification (UNSM) on the corrosion and stress corrosion cracking behavior of low carbon steel (ASTM A139) welded joint in the simulated district heating water (internal heating water) were investigated. After UNSM treatment, the microstructures of welded joint were transformed from the grain boundary ferrite and widmanstätten ferrite to polygonal ferrite accompanied by grain refinement. In electrochemical tests, the corrosion resistance of the welded joint was increased after UNSM treatment as a result of the grain refinement and improved stability of the oxide film. The stress corrosion cracking behavior was measured by slow strain rate tests with accelerated anodic and cathodic reactions. The results indicated that the UNSM treatment had a significant effect on the corrosion condition, whereas UNSM had no effect on hydrogen embrittlement.

This study examined the effect of corrosion on mechanical properties of welded carbon steel pipe in district heating water. To evaluate the corrosion properties, potentiodynamic tests were conducted and a galvanostatic test was used to accelerate corrosion. Tensile tests and microstructure observations were performed to figure out the degradation of the corroded region, and stress intensity factors were calculated. As a result of the potentiodynamic tests, welded carbon steel pipe showed uniform corrosion and the total charge was calculated. Using the galvanostatic test, the current density at the equivalent aging time was applied to the specimens. The tensile tests showed that according to corrosion damages, mechanical properties were degraded due to corrosion. Through the microstructure observations and calculations of stress intensity factors, the corrosion of the welded carbon steel pipe induced the degradation of mechanical properties. The mode of fracture was changed from ductile to brittle fracture with increasing aging time.

This paper presents a four-channel time-interleaved high-speed current-steering DAC with a proposed two-stage analog multiplexer (MUX). Optimum switching times of the cascaded MUX and the sub-DACs are guaranteed by background clock phase calibration with a proposed maximum-overlap-based phase detector. A 6b 28GS/s prototype DAC fabricated in 40nm CMOS achieves a SFDR of 34.6dB at a Nyquist input and consumes 103mW under dual supply voltages of 1.1V and 1.6V.

Let $(M,g_M,\mathcal F)$ be a closed, connected Riemannian manifold with a Riemannian foliation $\mathcal F$ of nonzero constant transversal scalar curvature. When $M$ admits a transversal nonisometric conformal field, we find some generalized conditions that $\mathcal F$ is transversally isometric to the sphere., Comment: 12 pages

The purpose of this study was to verify whether there are any differences in the level of exercise self-efficacy and perceived health status according to the stage of change for exercise behaviors in older adults. The subjects consisted of 231 older adults (91 male, 140 female) by convenience sampling residing in city D. The collected dates were analyzed using one-way ANOVA, Tukey HSD, and simple regression analysis by SPSS WIN 21.0 program. Moreover, all statistical significance level was set at a=.05. The study results were as follows: Analysis of variance showed that exercise self-efficacy showed significant differences according to the stage of change for exercise behaviors, and as a result of the posthoc analysis, it was found that as the stage became higher, their exercise self-efficacy became higher as well. Perceived health status showed significant differences according to the stage of change for exercise behaviors, and as a result of the posthoc analysis, it was found that as the stage became higher, their perceived health status became higher as well. Analysis of variance showed that exercise self-efficacy and perceived health status were significantly associated with the stages of exercise behavior change. This study identified that exercise self-efficacy and perceived health status were significant variables to explain a possible relationship with exercise stages of older adults. This study provides new information to influence the development of the better health promotion and exercise intervention for older adults in the community.

Leadership is one of the most studied topics in the organization sciences, and employee engagement one of the more recent. However, the relationship between leadership and employee engagement has not been widely investigated. As many organizations invest significant resources in retaining, developing, and engaging employees, human resource development (HRD) professionals are tasked to develop and partner with leaders to deliver those strategies effectively. Thus, a comprehensive understanding on the relationship and mechanism between leadership and engagement is essential to HRD professionals informing leaders on how best to cultivate positive results in followers. In this vein, this research conducted an extensive review of empirical and conceptual studies that examined the relationship between leadership and employee engagement, analyzed/synthesized the studies into integrated frameworks for the leadership–engagement relationship, and proposed future research agendas.

Purpose – This aim of the current research is to provide empirical evidence for the relationships among several organizational factors affecting team performance improvement, including the learning organization and employee engagement. In addition, the mediating effect of employee engagement was assessed to explain team performance improvement within the supportive learning organization. The target sample consisted of major Korean for-profit firms, and a total of 309 cases were used for data analyses. Structural equation modeling was used along with basic descriptive and multivariate research assumption tests. Results support that cultural aspects of the learning organization in Korean for-profit firms positively and directly affect the employee engagement, whereas cultural aspects of the learning organization positively affect team performance positively and indirectly only through employee engagement, and employee engagement plays a full mediating role in explaining the relationship between the learning organization and team performance. Conclusions are discussed, followed by implications for organizational development, limitations and future research suggestions. Design/methodology/approach – The target sample consisted of major Korean for-profit firms, and a total of 309 cases were used for data analyses. Structural equation modeling was used along with basic descriptive and multivariate research assumption tests. Findings – Results support that cultural aspects of the learning organization in Korean for-profit firms positively and directly affect the employee engagement, while cultural aspects of the learning organization positively affect team performance positively and indirectly only through the employee engagement, and the employee engagement plays a full mediating role in explaining the relationship between the learning organization and team performance. Originality/value – This research has not been conducted in the Korean context, and this research will provide not only scholarly evidences on the importance of the learning organization for performance improvement, but also the practical guideline for the practitioners to make effort to make their organizations as the learning organization for performance improvement.

The effects of hydro co-extrusion on the microstructure changes of aluminum hybrid duo-cast Al 3003/Al 4004 clad materials were studied. The specimen of duo-cast Al 3003/Al 4004 clad materials was in circle shape, and was composed of Al 3003(outside) and Al 4004(inside) materials. The specimen was extruded by the hydro co-extrusion equipment. The manufacturing conditions of the specimen were 423 K in temperature and 5 in extrusion ratio. The dimensions of the specimen were 80 mm in diameter of the Al 4004 material and 35 mm in thickness of the Al 3003 material before the hydro co-extrusion process, and 30 mm in diameter and about 5 mm in thickness after the extrusion process, respectively. The microstructure and the hardness for two specimens were investigated. The hardness value of cross section in the duo-cast Al 3003/Al 4004 clad materials before the extrusion process was increased in form of the parabola toward the center. However, after the extrusion process, it was almost constant in the portion of Al 4004 material. Lots of big voids above 1 mm in diameter in the specimen existed in the interfacing region of Al 3003 and Al 4004 materials before the extrusion process. These big voids disappeared after the process of hydro co-extrusion.

Ever increasing “Big data” can only be effectively processed by parallel computing. Parallel computing refers to a high performance computational method that achieves effectiveness by dividing a big query into smaller subtasks and aggregating results from subtasks to provide an output. However, it is well-known that parallel computing does not achieve scalability which means that performance is improved linearly by adding more computers because it requires a very careful assignment of tasks to each node and collecting results in a timely manner. Hadoop is one of the most successful platforms to attain scalability. In this paper, we propose a measurement for Hadoop optimization by utilizing a Lorenz curve which is a proxy for the inequality of hardware resources. Our proposed index takes into account the intrinsic overhead of Hadoop systems such as CPU, disk I/O and network. Therefore, it also indicates that a given Hadoop can be improved explicitly and in what capacity. Our proposed method is illustrated with experimental data and substantiated by Monte Carlo simulations.

Over the past several decades, biologists have conducted numerous studies examining both general and specific functions of proteins. Generally, if similarities in either the structure or sequence of amino acids exist for two proteins, then a common biological function is expected. Protein function is determined primarily based on the structure rather than the sequence of amino acids. The algorithm for protein structure alignment is an essential tool for the research. The quality of the algorithm depends on the quality of the similarity measure that is used, and the similarity measure is an objective function used to determine the best alignment. However, none of existing similarity measures became golden standard because of their individual strength and weakness. They require excessive filtering to find a single alignment. In this paper, we introduce a new strategy that finds not a single alignment, but multiple alignments with different lengths. This method has obvious benefits of high quality alignment. However, this novel method leads to a new problem that the running time for this method is considerably longer than that for methods that find only a single alignment. To address this problem, we propose algorithms that can locate a common region (CORE) of multiple alignment candidates, and can then extend the CORE into multiple alignments. Because the CORE can be defined from a final alignment, we introduce CORE* that is similar to CORE and propose an algorithm to identify the CORE*. By adopting CORE* and dynamic programming, our proposed method produces multiple alignments of various lengths with higher accuracy than previous methods. In the experiments, the alignments identified by our algorithm are longer than those obtained by TM-align by 17 % and 15.48 %, on average, when the comparison is conducted at the level of super-family and fold, respectively.

This study examines the effect of the continuous decrease of the nitrite concentration on the corrosion properties of a carbon steel pipeline in deaerated synthetic tap water. Passive film, which is composed mainly of maghemite (γ-Fe 2 O 3 ), was formed in synthetic tap water containing 200 ppm nitrite. A carbon steel pipeline in synthetic tap water containing 100 ppm nitrite was more susceptible to localised corrosion than that containing 50 ppm nitrite due to the effect of the small anode and large cathode area. Uniform corrosion dominates in synthetic tap water containing 50 ppm nitrite.

The massively parallel sequencing technologies have recently flourished and dramatically cut the cost to sequence personal human genomes. Haplotype assembly from personal genomes sequenced using the massively parallel sequencing technologies is becoming a cost-effective and promising tool for human disease study. Computational assembly of haplotypes has been proved to be very accurate, but obviously contains errors. Here we present a tool, HapEdit, to assess the accuracy of assembled haplotypes and edit them manually. Using this tool, a user can break erroneous haplotype segments into smaller segments, or concatenate haplotype segments if the concatenated haplotype segments are sufficiently supported. A user can also edit bases with low-quality scores. HapEdit displays haplotype assemblies so that a user can easily navigate and pinpoint a region of interest. As inputs, HapEdit currently takes reads from the Polonator, Illumina, SOLiD, 454 and Sanger sequencing technologies.

A corrosion failure of materials, often exposed to the corrosive environment in the district heating facility, has a critical influence on structural integrity. Thus, it is very important to investigate the cause of the failure for the establishment of effective prevention methodology. In this study, the failure analysis was performed in the case that a water wall tube for a boiler in district heating was fractured along the axial direction of the tube that is SA-210 Grade A1, which is frequently used for the boiler. The feed water temperature was about 220°C and the operating pressure was about 10 MPa. For the visual inspection of the failed part, the wall thinning and failure were observed in the location where the heat was directly reached. Sodium and iron oxides were only found in the inner surface of the tube, as confirmed by x-ray diffraction, and it indicates that hydrogen is generated by the mechanism of the caustic corrosion, resulting in hydrogen embrittlement near the inner surface. The microstructural changes along the direction of radial and hoop were intensively examined. A number of microvoids were formed along the grain boundary, leading to some microcracks in the location inside the tube. As a result, it is concluded that an unstable magnetite film at elevated temperature under tensile residual stresses developed along the hoop direction in the interior of the tube undergoes the caustic corrosion, and microvoids or microcracks along the grain boundary formed due to hydrogen embrittlement cause a final fracture of the tube.

Flash memory has critical drawbacks such as long latency of its write operation and a short life cycle. In order to overcome these limitations, the number of write operations to flash memory devices needs to be minimized. The B-Tree index structure, which is a popular hard disk based index structure, requires an excessive number of write operations when updating it to flash memory. To address this, it was proposed that another layer that emulates a B-Tree be placed between the flash memory and B-Tree indexes. This approach succeeded in reducing the write operation count, but it greatly increased search time and main memory usage. This paper proposes a B-Tree index extension that reduces both the write count and search time with limited main memory usage. First, we designed a buffer that accumulates update requests per leaf node and then simultaneously processes the update requests of the leaf node carrying the largest number of requests. Second, a type of header information was written on each leaf node. Finally, we made the index automatically control each leaf node size. Through experiments, the proposed index structure resulted in a significantly lower write count and a greatly decreased search time with less main memory usage, than placing a layer that emulates a B-Tree.

Due to the rapid development in mobile communication technologies, the usage of mobile devices such as cell phone or PDA has increased significantly. As different devices require different applications, various new services are being developed to satisfy the needs. One of the popular services under heavy demand is the location-based service (LBS) that exploits the spatial information of moving objects per temporal changes. In order to support LBS well, in this paper, we investigate how spatio-temporal information of moving objects can be efficiently stored and indexed. In particular, we propose a novel location encoding method based on hierarchical administrative district information. Our proposal is different from conventional approaches where moving objects are often expressed as geometric points in two-dimensional space, (x,y). Instead, in ours, moving objects are encoded as one-dimensional points by both administrative district as well as road information. Our method becomes especially useful for monitoring traffic situation or tracing location of moving objects through approximate spatial queries.