• Bulletin of the Korean Space Science Society
• /
• 2010.04a
• /
• pp.25.1-25.1
• /
• 2010

This talk outlines the current understanding of solar flares, mainly focusing on magnetohydrodynamic (MHD) processes. A flare causes plasma heating, mass ejection, and particle acceleration that generates high-energy particles. The key physical processes related to a flare are: the emergence of magnetic field from the solar interior to the solar atmosphere (flux emergence), formation of current-concentrated areas (current sheets) in the corona, and magnetic reconnection proceeding in current sheets that causes shock heating, mass ejection, and particle acceleration. A flare starts with the dissipation of electric currents in the corona, followed by various dynamic processes which affect lower atmospheres such as the chromosphere and photosphere. In order to understand the physical mechanism for producing a flare, theoretical modeling has been developed, in which numerical simulation is a strong tool reproducing the time-dependent, nonlinear evolution of plasma before and after the onset of a flare. In this talk we review various models of a flare proposed so far, explaining key features of these models. We show observed properties of flares, and then discuss the processes of energy build-up, release, and transport, all of which are responsible for producing a flare. We come to a concluding view that flares are the manifestation of recovering and ejecting processes of a global magnetic flux tube in the solar atmosphere, which was disrupted via interaction with convective plasma while it was rising through the convection zone.

• Journal of the Korean Society of Safety
• /
• v.33 no.3
• /
• pp.58-64
• /
• 2018

Recently, a lot of accident report documents have accumulated in almost all of industries, including critical information of accidents. Accordingly, text data contained in accident report documents are considered useful information for understanding accident processes. However, there has been a lack of systematic approaches to analyzing accident report documents. In this respect, this paper aims at proposing text analytics approach to extracting critical information on accident processes. To be specific, major causes of the accident occurrence are classified based on text information contained in accident report documents by using both textmining and latent Dirichlet allocation (LDA) algorithms. The textmining algorithm is used to structure the document-term matrix and the LDA algorithm is applied to extract latent topics included in a lot of accident report documents. We extract ten topics of accidents as accident types and related keywords of accidents with respect to each accident type. The cause-and-effect diagram is then depicted as a tool for navigating processes of the accident occurrence by structuring causes extracted from LDA. Further, the trends of accidents are identified to explore patterns of accident occurrence in each of types. Three patterns of increasing to decreasing, decreasing to increasing, or only increasing are presented in the case of a chemical plant. The proposed approach helps safety managers systematically supervise the causes and processes of accidents through analysis of text information contained in accident report documents.

• Journal of Information Technology Applications and Management
• /
• v.10 no.4
• /
• pp.103-118
• /
• 2003

This study presents a database quality evaluation framework. As a way to build a framework, this study expands data quality management to include data transformation processes as well as data. Further, an information structure graph is applied to represent data transformations processes. An information structure graph is absed on a relational database scheme. Thus, data transformation processes may be stored in a relational database. This kind of integration of data transformation metadata with technical metadata eases evaluation of database qualities and their causes.

• International conference on construction engineering and project management
• /
• 2009.05a
• /
• pp.184-189
• /
• 2009

In 2008 the total estimated failure costs in the Netherlands was estimated to be 11.4% of the industry's turnover compared to 7.7% seven years earlier. Failure costs can be the consequence of rework as a result of failure to conform to the product requirements and specifications or due to inefficient processes and bad management practices. Many construction companies however are unaware of the exact nature of these costs, their root causes or how to control them. This paper describes work carried out in the Netherlands to identify the different types of failure costs in construction and their root causes. The research described builds on previous findings by another research institution and expands it to include information collected from project cases and a survey of a number of project managers in the construction industry. The paper describes the analysis of the results from cases and the survey to identify the root causes of failure costs. Research shows, for example, that many failure costs are related to the client taking late decisions and making changes to the project requirements.

• Journal of Haehwa Medicine
• /
• v.17 no.1
• /
• pp.157-166
• /
• 2008

1. Vertigo and dizziness is also called as Mok-hyun, Hyun-mo, Pung-hyun, Du-pung-hyun-un, Du-sun. 2. Causes and processes of Vertigo and dizziness are mainly divided into external infection and internal damage. Wind, cold, dampness and summer heat are included in the one and in the other, vital energy and blood deficiency, insufficiency of the liver and kidney, retention of phlegm and fluid, emotional disorder and so on. 3. Symptoms of vertigo and dizziness are disequilibrium, nausea, inability of hearing, vomiting, sweating and syncope. 4. Treating of vertigo and dizziness are recovery of vital energy and blood deficiency, strenthening of insufficiency of the liver and kidney, drying of dampness and removing of phlegm.

• Journal of Korean Society for Quality Management
• /
• v.40 no.2
• /
• pp.106-116
• /
• 2012

This paper aims to develop the adequate quality cost model at a company which delivers ICT(information communication technology) services. One particular business unit was in the first instance selected and quality costs were then analysed at an organization level, for a department and for specific processes. Some areas were determined for quality improvement at each level and their causes were also investigated. However, the existing PAF(prevention, appraisal and failure) models reveled some limitations because the ICT services company included the different number of large and complicated business processes. The PAF model did not sufficiently highlight the detailed causes of failure costs. It did not also stimulate the relevant department's strong responsibility to improve such problems. Both micro PAF and process cost models were proposed in order to cope with this. In final, it explains the relationship between six sigma and quality costing, suggesting how to use the quality costing results as a means of promoting either continuous improvement or innovation in a case company.

• Journal of the Korea Safety Management & Science
• /
• v.17 no.2
• /
• pp.215-228
• /
• 2015

A creative innovation and an innovative problem-solving of industrial companies can be achieved by overcoming the challenges of technical and physical contradictions. The approaches to address conflicting and paradoxical problems, such as technical and physical contradictions have a crucial role in advancing the quality assessment for manufacturer and service provider. The term, technical contradiction, depicts the state that improvement of one ends of IFR (Ideal Final Result) leads to unfavorable condition of the other ends, and results in conflicting problem. Another type of contradictions that's discussed in this study is a physical contradiction which is due to two mutually opposing states of the means of ends, and gives paradoxical situation. By integrating the means-ends chain perspectives, the physical contradiction that is a specifically root-causes, "means", can be initially addressed to resolve the downstream problem of technical contradiction which represents a general and abstract goals, "ends". This research suggests IFR resolution processes to handle both physical contradiction of means and technical contradiction of ends by employing causal relationship with IFR, effects and causes. In summary, the study represents three major processes that resolve such contradictions are demonstrated as follows: 1) Derivation of causal and hierarchical relationship among IFR, ends and means by considering CAED (Cause-And-Effect Diagram) and LT (Logic Tree). 2) Identification of causal relationship between physical contradiction and technical contradiction by using TPCT (TRIZ Physical Contradiction Tree) and TCD (Technical Contradiction Diagram). 3) Application of integrated TRIZ principles by classifying 40 inventive principles into 4 general conditions of the separation principle of mutually opposite states in space, in time, based on conditions, and between the parts and the whole. In order to validate the proof of proposed IFR resolution processes, the analysis of the TRIZ case studies from National Quality Circle Contest in the years, 2011 to 2014 have been proposed. The suggested guidelines that are built based on TRIZ principles can uniquely enhance the process of quality innovation and assessment for quality practitioners.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2005.06a
• /
• pp.133-138
• /
• 2005

Automotive pulleys play a key role in driving the cooling pump, oil pump, air-conditioner and so on by using an engine power. Researches on design processes and technologies of the pulleys can be found in many literatures. On the other hand, the areas related to manufacturing processes of the pulleys have been treated negligently. Vast data extracted from various information systems are transformed, integrated, and summarized to become a special database for helping users make a decision. The database, namely the data warehouse has been popularly used in the marketing and customer management of enterprises and recently applied to improve the design and manufacturing processes. In this study the manufacturing process of pulleys were analyzed through the intensive investigation of shop-floors and the interviews with workers and managers. The defects generated during a manufacturing process were categorized in a few types and the causes of defects examined for extracting the dominant parameters in the setup process for producing pulleys. As the first step to construct the data warehouse for the manufacturing processes of pulleys, authors proposed its architecture focused on the reduction of defect rate during the setup process.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2021.05a
• /
• pp.38-39
• /
• 2021

The use of temporary container classrooms has increased in recent years due to the development of the construction industry and renovation or rehabilitation of schools. Therefore, various problems, such as errors during assembling, design and insulation issues, and noise problems, have surfaced during the construction of temporary container classrooms. This study analyzes the causes of assembly errors during the manufacturing and installation processes to improve the quality of temporary container classrooms. Assembly errors are caused by non-level planes and inaccurate cutting during the manufacturing process. In the installation process, poor leveling is a major factor that causes errors during the assembly of temporary container classrooms. These causes result in uneven horizontal or vertical planes and uneven height. To solve these problems, quality improvement measures, such as pin connection, jig, joint coupling, and surface plates are proposed in this study.

• Journal of Engineering Education Research
• /
• v.13 no.2
• /
• pp.74-77
• /
• 2010

This article proposes to examine how the study of failure differs from other technical subjects, and how to turn failure experiences to one's advantage. The authors surveyed the properties of failures in PBL (Project Based Learning) and also examined students' interest and understanding of failure, after introducing failure examples. To investigate how students communicate failure experiences to third parties, reports of the failure experience in PBL were evaluated. From above mentioned surveys, we get the following results. The typical causes of failure in educational institutions are lack of skill in manufacturing and inadequate planning, which conversely are minor causes of failure in the industry. A knowledge database on failure, employed commonly in industry, is not effective in PBL, because projects in educational institutes are usually changed every year. Case studies in failure can be approached from many points of view including causes, processes, effects and safety measures. While teachers should emphasize the notable points in the failure examples in introducing examples of specific topics in machine design, teachers should explain the multiple aspects in the failure examples to educate students about the complexity of actual accidents.