A case study of customer satisfaction for information technology solutions

There are numerous information technology solutions including hardware and software. A company that provides the solution should have knowledge of the customer needs in the purpose of sailing strategy or upgrade policy. The needs are also directly connected to the user satisfaction. However, the users have respective points of view in the needs as well as they may not identify the requirements to improve the solution. SERVQUAL can be an appropriate method to define and measure the customer satisfaction for the information technology solutions. As a case study of the customer satisfaction, the modified SERVQUAL items and scoring method are applied to a cyber-infrastructure system named CyberL ab in Korea. The measurement results of user satisfaction for CyberL ab are provided to confirm that our proposed method performs as we intended. From the results, we can score the satisfaction level of users and identify their needs in the various aspects. The total user satisfaction level for CyberL ab is scored by 88.3.

Acoustofluidic separation of prolate and spherical micro-objects

Most microfluidic separation techniques rely largely on object size as a separation marker.The ability to separate micro-objects based on their shape is crucial in various biomedical and chemical assays.Here,we develop an ondemand,label-free acoustofluidic method to separate prolate ellipsoids from spherical microparticles based on traveling surface acoustic wave-induced acoustic radiation force and torque.The freely rotating non-spherical microobjects were aligned under the progressive acoustic field by the counterrotating radiation torque,and the major axis of the prolate ellipsoids was parallel to the progressive wave propagation.The specific alignment of the ellipsoidal particles resulted in a reduction in the cross-sectional area perpendicular to the wave propagation.As a consequence,the acoustic backscattering decreased,resulting in a decreased magnitude of the radiation force.Through the variation in radiation force,which depended on the micro-object morphology enabled the acoustofluidic shape-based separation.We conducted numerical simulations for the wave scattering of spherical and prolate objects to elucidate the working mechanism underlying the proposed method.A series of experiments with polystyrene microspheres,prolate ellipsoids,and peanut-shaped microparticles were performed for validation.Through quantitative analysis of the separation efficiency,we confirmed the high purity and high recovery rate of the proposed acoustofluidic shapebased separation of micro-objects.As a bioparticle,we utilize Thalassiosira eccentrica to perform shape-based separation,as the species has a variety of potential applications in drug delivery,biosensing,nanofabrication,bioencapsulation and immunoisolation.

Elasto-inertial microfluidic separation of microspheres with submicron resolution at high-throughput

Elasto-inertial microfluidic separation offers many advantages including high throughput and separation resolution.Even though the separation efficiency highly depends on precise control of the flow conditions,no concrete guidelines have been reported yet in elasto-inertial microfluidics.Here,we propose a dimensionless analysis for precise estimation of the microsphere behaviors across the interface of Newtonian and viscoelastic fluids.Reynolds number,modified Weissenberg number,and modified elastic number are used to investigate the balance between inertial and elastic lift forces.Based on the findings,we introduce a new dimensionless number defined as the width of the Newtonian fluid stream divided by microsphere diameter.The proposed dimensionless analysis allows us to predict whether the microspheres migrate across the co-flow interface.The theoretical estimation is found to be in good agreement with the experimental results using 2.1-and 3.2-μm-diameter polystyrene microspheres in a co-flow of water and polyethylene oxide solution.Based on the theoretical estimation,we also realize submicron separation of the microspheres with 2.1 and 2.5μm in diameter at high throughput,high purity(>95%),and high recovery rate(>97%).The applicability of the proposed method was validated by separation of platelets from similar-sized Escherichia coli(E.coli).

Bioprinting Methods for Fabricating In Vitro Tubular Blood Vessel Models

Dysfunctional blood vessels are implicated in various diseases,including cardiovascular diseases,neurodegenerative diseases,and cancer.Several studies have attempted to prevent and treat vascular diseases and understand interactions between these diseases and blood vessels across different organs and tissues.Initial studies were conducted using 2-dimensional(2D)in vitro and animal models.However,these models have difficulties in mimicking the 3D microenvironment in human,simulating kinetics related to cell activities,and replicating human pathophysiology;in addition,3D models involve remarkably high costs.Thus,in vitro bioengineered models(BMs)have recently gained attention.BMs created through biofabrication based on tissue engineering and regenerative medicine are breakthrough models that can overcome limitations of 2D and animal models.They can also simulate the natural microenvironment in a patient-and target-specific manner.In this review,we will introduce 3D bioprinting methods for fabricating bioengineered blood vessel models,which can serve as the basis for treating and preventing various vascular diseases.Additionally,we will describe possible advancements from tubular to vascular models.Last,we will discuss specific applications,limitations,and future perspectives of fabricated BMs.

Bootstrap generated confidence interval for time averaged measure

In the simulation output analysis,there are some measures that should be calculated by time average concept such as the mean queue length.Especially,the confidence interval of those measures might be required for statistical analysis.In this situation,the traditional method that utilizes the central limit theorem(CLT)is inapplicable if the output data set has autocorrelation structure.The bootstrap is one of the most suitable methods which can reflect the autocorrelated phenomena in statistical analysis.Therefore,the confidence interval for a time averaged measure having autocorrelation structure can also be calculated by the bootstrap methods.This study introduces the method that constructs these confidence intervals applying the bootstraps.The bootstraps proposed are the threshold bootstrap(TB),the moving block bootstrap(MBB)and stationary bootstrap(SB).Finally,some numerical examples will be provided for verification.

Ab initio electron-defect interactions using Wannier functions

Computing electron–defect(e–d)interactions from first principles has remained impractical due to computational cost.Here we develop an interpolation scheme based on maximally localized Wannier functions(WFs)to efficiently compute e–d interaction matrix elements.The interpolated matrix elements can accurately reproduce those computed directly without interpolation and the approach can significantly speed up calculations of e–d relaxation times and defect-limited charge transport.We show example calculations of neutral vacancy defects in silicon and copper,for which we compute the e–d relaxation times on fine uniform and random Brillouin zone grids(and for copper,directly on the Fermi surface),as well as the defect-limited resistivity at low temperature.Our interpolation approach opens doors for atomistic calculations of charge carrier dynamics in the presence of defects.