Comparison of standard-setting methods for the Korean Radiological Technologist Licensing Examination: Angoff, Ebel, bookmark, and Hofstee

Purpose This study aimed to compare the possible standard-setting methods for the Korean Radiological Technologist Licensing Examination, which has a fixed cut score, and to suggest the most appropriate method. Methods Six radiological technology professors set standards for 250 items on the Korean Radiological Technologist Licensing Examination administered in December 2016 using the Angoff, Ebel, bookmark, and Hofstee methods. Results With a maximum percentile score of 100, the cut score for the examination was 71.27 using the Angoff method, 62.2 using the Ebel method, 64.49 using the bookmark method, and 62 using the Hofstee method. Based on the Hofstee method, an acceptable cut score for the examination would be between 52.83 and 70, but the cut score was 71.27 using the Angoff method. Conclusion The above results suggest that the best standard-setting method to determine the cut score would be a panel discussion with the modified Angoff or Ebel method, with verification of the rated results by the Hofstee method. Since no standard-setting method has yet been adopted for the Korean Radiological Technologist Licensing Examination, this study will be able to provide practical guidance for introducing a standard-setting process

Epidemics of enterovirus infection in Chungnam Korea, 2008 and 2009

Previously, we explored the epidemic pattern and molecular characterization of enteroviruses isolated in Chungnam, Korea from 2005 to 2006. The present study extended these observations to 2008 and 2009. In this study, enteroviruses showed similar seasonal prevalent pattern from summer to fall and age distribution to previous investigation. The most prevalent month was July: 42.9% in 2008 and 31.9% in 2009. The highest rate of enterovirus-positive samples occurred in children < 1-year-old-age. Enterovirus-positive samples were subjected to sequence determination of the VP1 region, which resolved the isolated enteroviruses into 10 types in 2008 (coxsackievirus A4, A16, B1, B3, echovirus 6, 7, 9, 11, 16, and 30) and 8 types in 2009 (coxsackievirus A2, A4, A5, A16, B1, B5, echovirus 11, and enterovirus 71). The most prevalent enterovirus serotype in 2008 and 2009 was echovirus 30 and coxsackievirus B1, respectively, whereas echovirus 18 and echovirus 5 were the most prevalent types in 2005 and 2006, respectively. Comparison of coxsackievirus B1 and B5 of prevalent enterovirus type in Korea in 2009 with reference strains of each same serotype were conducted to genetic analysis by a phylogenetic tree. The sequences of coxsackievirus B1 strains segregated into four distinct clusters (A, B, C, and D) with some temporal and regional sub-clustering. Most of Korean coxsackievirus B1 strains in 2008 and 2009 were in cluster D, while only "Kor08-CVB1-001CN" was cluster C. The coxsackievirus B5 strains segregated in five distinct genetic groups (clusters A-E) were supported by high bootstrap values. The Korean strains isolated in 2001 belonged to cluster D, whereas Korean strains isolated in 2005 and 2009 belonged to cluster E. Comparison of the VP1 amino acid sequences of the Korean coxsackievirus B5 isolates with reference strains revealed amino acid sequence substitutions at nine amino acid sequences (532, 562, 570, 571, 576-578, 582, 583, and 585)

Updates on the genetic variations of Norovirus in sporadic gastroenteritis in Chungnam Korea, 2009-2010

Previously, we explored the epidemic pattern and molecular characterization of noroviruses (NoVs) isolated in Chungnam, Korea in 2008, and the present study extended these observations to 2009 and 2010. In Korea, NoVs showed the seasonal prevalence from late fall to spring, and widely detected in preschool children and peoples over 60 years of age. Epidemiological pattern of NoV was similar in 2008 and in 2010, but pattern in 2009 was affected by pandemic influenza A/H1N1 2009 virus. NoV-positive samples were subjected to sequence determination of the capsid gene region, which resolved the isolated NoVs into five GI (2, 6, 7, 9 and 10) and eleven GII genotypes (1, 2, 3, 4, 6, 7, 8, 12, 13, 16 and 17). The most prevalent genotype was GII.4 and occupied 130 out of 211 NoV isolates (61.6%). Comparison of NoV GII.4 of prevalent genotype in these periods with reference strains of the same genotype was conducted to genetic analysis by a phylogenetic tree. The NoV GII.4 strains were segregated into seven distinct genetic groups, which are supported by high bootstrap values and previously reported clusters. All Korean NoV GII.4 strains belonged to either VI cluster or VII cluster. The divergence of nucleotide sequences within VI and VII intra-clusters was > 3.9% and > 3.5%, respectively. The "Chungnam(06-117)/2010" strain which was isolated in June 2010 was a variant that did not belong to cluster VI or VII and showed 5.8-8.2%, 6.2-8.1% nucleotide divergence with cluster VI and VII, respectively

WormBase: a modern Model Organism Information Resource

WormBase (https://wormbase.org/) is a mature Model Organism Information Resource supporting researchers using the nematode Caenorhabditis elegans as a model system for studies across a broad range of basic biological processes. Toward this mission, WormBase efforts are arranged in three primary facets: curation, user interface and architecture. In this update, we describe progress in each of these three areas. In particular, we discuss the status of literature curation and recently added data, detail new features of the web interface and options for users wishing to conduct data mining workflows, and discuss our efforts to build a robust and scalable architecture by leveraging commercial cloud offerings. We conclude with a description of WormBase's role as a founding member of the nascent Alliance of Genome Resources

WormBase: a modern Model Organism Information Resource

WormBase (https://wormbase.org/) is a mature Model Organism Information Resource supporting researchers using the nematode Caenorhabditis elegans as a model system for studies across a broad range of basic biological processes. Toward this mission, WormBase efforts are arranged in three primary facets: curation, user interface and architecture. In this update, we describe progress in each of these three areas. In particular, we discuss the status of literature curation and recently added data, detail new features of the web interface and options for users wishing to conduct data mining workflows, and discuss our efforts to build a robust and scalable architecture by leveraging commercial cloud offerings. We conclude with a description of WormBase's role as a founding member of the nascent Alliance of Genome Resources

Alliance of Genome Resources Portal: unified model organism research platform

The Alliance of Genome Resources (Alliance) is a consortium of the major model organism databases and the Gene Ontology that is guided by the vision of facilitating exploration of related genes in human and well-studied model organisms by providing a highly integrated and comprehensive platform that enables researchers to leverage the extensive body of genetic and genomic studies in these organisms. Initiated in 2016, the Alliance is building a central portal (www.alliancegenome.org) for access to data for the primary model organisms along with gene ontology data and human data. All data types represented in the Alliance portal (e.g. genomic data and phenotype descriptions) have common data models and workflows for curation. All data are open and freely available via a variety of mechanisms. Long-term plans for the Alliance project include a focus on coverage of additional model organisms including those without dedicated curation communities, and the inclusion of new data types with a particular focus on providing data and tools for the non-model-organism researcher that support enhanced discovery about human health and disease. Here we review current progress and present immediate plans for this new bioinformatics resource

Alliance of Genome Resources Portal: unified model organism research platform

The Alliance of Genome Resources (Alliance) is a consortium of the major model organism databases and the Gene Ontology that is guided by the vision of facilitating exploration of related genes in human and well-studied model organisms by providing a highly integrated and comprehensive platform that enables researchers to leverage the extensive body of genetic and genomic studies in these organisms. Initiated in 2016, the Alliance is building a central portal (www.alliancegenome.org) for access to data for the primary model organisms along with gene ontology data and human data. All data types represented in the Alliance portal (e.g. genomic data and phenotype descriptions) have common data models and workflows for curation. All data are open and freely available via a variety of mechanisms. Long-term plans for the Alliance project include a focus on coverage of additional model organisms including those without dedicated curation communities, and the inclusion of new data types with a particular focus on providing data and tools for the non-model-organism researcher that support enhanced discovery about human health and disease. Here we review current progress and present immediate plans for this new bioinformatics resource

다단 슈라우드형 축류 압축기 유동의 비정상 운동학에 대한 실험적 연구

학위논문(박사)--서울대학교 대학원 :공과대학 기계항공공학부,2019. 8. 송성진.An experimental investigation has been conducted to identify the unsteady kinematics of shrouded stator of a low-speed multistage axial compressor. Unsteady velocity distributions have been measured at upstream and downstream of 3rd shrouded stator using single-element 45° slanted hot-wires. The data have been ensemble-averaged to obtain the timewise variation of velocity vectors upstream and downstream of the shrouded 3rd stator. The width and velocity disturbances of 3rd stator wake varied by the merge with 3rd rotor wakes. Between the two 3rd rotor wakes, a pseudo-wake region is observed, which is presumed to be created by the recirculation due to the negative jet of the 3rd rotor wakes. This velocity disturbance is attenuated by the viscous mixing and wake stretching as the 3rd wakes are transported downstream. Because of the velocity disturbances, the aerodynamic properties downstream of the stator blade vary. The hubside corner separation of the multistage shrouded stator alters the unsteady kinematics of the hubside shrouded stator flow. The attenuation of the wake is lower at the hubside due to the reduced effective passage width by the corner separation. In addition to this, this hub corner separation triggers the hubside positive radial movements at the upstream and downstream of hubside of the 3rd stator. This increases the timewise variation of the hubside aerodynamic properties, deviating the shrouded stator off from its designed flow condition further compared with the midspan region. Changing the operating conditions have affected the hubside unsteady flow structures. At near stall cases, the widths of wakes and hub corner separation are increased, but the hubside unsteady flow structure is qualitatively similar to that of the design cases. For the higher flow rate cases, the width and the magnitude of the corner separation are reduced, resulting in the disappearances of a positive radial movement inside the corner separation.다단 압축기 슈라우드형 정익 허브의 유동 구조가 상단 동익 후류에 미치는 영향을 파악하기 위해 저속 4단 슈라우드형 축류 압축기의 3단 정익 상단 및 하단에서의 비정상 속도 분포를 핫와이어를 이용하여 최초로 측정하였다. 상단 동익 후류의 폭과 강도는 상단 정익 후류와의 상호작용으로 인해 변동한다. 두 동익 후류 사이에는, 동익 후류로 인해 생긴 순환류로 인해 동익 후류와 유사하게 보이는 유동 구조가 형성된다. 동익 후류로 인해 생긴 유동의 시간에 따른 변화는 유동의 점성과 후류의 늘어남으로 인해 완화된다. 다단 슈라우드형 정익의 허브 모서리 유동 박리는 정익 허브의 비정상 운동학에 영향을 준다. 유동 박리가 허브의 유효 면적을 줄여, 동익 후류의 완화를 억제한다. 또한, 유동 박리로 인해 슈라우드형 정익 상/하단에서 추가적인 반경방향 움직임이 형성된다. 이로 인해 동익 후류로 인한 유동의 시간에 따른 변화의 크기가 증가하여, 유동의 공력 성질이 시간에 따라 변하게 되며, 디자인 공력 조건에서 벗어난다. 압축기의 운전 조건을 바꿀 시 허브의 비정상 유동구조가 변화한다. 낮은 유량에서 운전했을 시, 후류와 모서리 유동 박리의 폭은 늘어나지만, 비정상 유동구조는 설계 운전조건에서의 경우와 정성적으로 동일하다. 높은 유량에서 운전했을 시, 모서리 유동 박리의 폭과 강도가 감소하여, 다른 운전 조건에서 보였던 모서리 박리 안에서의 반경방향 움직임이 사라진다.Abstract i Acknowledgments iii List of Figures vii List of Tables xiii Nomenclatures xiv Chapter 1. Introductions 1 1.1 Overview of the Study 1 1.2 Literature Review 9 1.3 Motivations and Objectives of the Study 30 1.4 Thesis Organization 34 Chapter 2. Experimental Configurations 35 2.1 Overview of Turbomachines for Research Purposes 35 2.2 Design Procedure of SNU Compressor 42 2.3 Instrumentations of SNU Compressor 69 2.4 Measuring Technique of 3D Velocity Vector 80 2.5 Measuring Planes and Conditions 82 Chapter 3. Unsteady Kinematics of Multistage Shrouded Stator Flow at Design Point 86 3.1 Unsteady Kinematics of the Flow Upstream of 3rd Stator 86 3.2 Unsteady Kinematics of the Flow Downstream of 3rd Stator 98 3.3 Variation of Aerodynamic Properties Downstream of 3rd Stator 113 Chapter 4. Effect of Corner Separation on Unsteady Kinematics and Flow Properties 118 4.1 Radial Movements Created by 3rd Rotor Wakes and Hubside Corner Separation 119 4.2 Reduced Attenuation of Velocity Disturbances by 3rd Rotor Wake due to Corner Separation 124 4.3 Increased Variation of Hubside Unsteady Aerodynamic Properties 132 Chapter 5. Effect of Flow Coefficients on Unsteady Kinematics of Shrouded Stator Flow 137 5.1 Unsteady Kinematics of Shrouded Stator Flow at Near Stall case 137 5.2 Unsteady Kinematics of Shrouded Stator Flow at Higher Flow Rate case 151 Chapter 6. Discussions 165 6.1 Comparison of the Unsteady Kinematics of Hubside Stator Flow with Different Stator Configuration 165 6.2 Effect of 3rd Rotor Wake on Hubside Vorticity Kinematics of Shrouded Stator 167 6.3 Impact of Hubside Corner Separation on Hubside Unsteady Kinematics of Shrouded Stator Flow and Aerodynamic Properties 169 6.4 Recommendations for Compressor Design 171 Chapter 7. Summary of the Study 172 7.1 Conclusions 172 7.2 Recommendations for the Future Work 175 References 177 Appendix A. Procedure for Selecting Bearings 186 Appendix B. Procedure of Bellmouth Calibration for Measuring Mass Flow Rate 193 Appendix C. Pitch and Yaw Angle Response of Hot-Wires Used for the Experiments 197 Abstract (Korean) 206Docto

Structure identification and dissociation enthalpy measurements of the CO2+N2 hydrates for their application to CO2 capture and storage

In this study, the mixed gas hydrates formed from the flue gas mixtures of CO2+N2 have been investigated with a primary focus on the structure identification and the dissociation enthalpy measurements. The stability conditions of the CO2+N2 gas hydrates are determined using an isochoric (PVT) method and a differential scanning calorimeter (DSC). It is found from the comparison of the hydrate phase equilibrium data measured using two methods that the DSC can be effectively used as an alternative method for measuring the stability conditions of the CO2+N2 gas hydrates. The microscopic analyses, such as powder X-ray diffraction and Raman spectroscopy, demonstrated that the gas mixtures of CO2+N2 form a structure I hydrate and that the structural transition does not occur in the range of the flue gas composition. To reveal the dissociation behavior of the mixed gas hydrates, the dissociation enthalpies of the CO2+N2 gas hydrates have been measured using a micro-differential scanning calorimeter (??-DSC). The dissociation heats of the CO2+N2 gas hydrates increased with an increase of the CO2 composition in the hydrate phase. The experimental results obtained in this study provide the thermodynamic and physical background required to estimate the heat liberated or absorbed during hydrate formation and dissociation and to predict the operation conditions for the gas hydrate-based CO2 capture and storage process.close0