• Journal of the Korea Safety Management & Science
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• v.17 no.1
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• pp.309-320
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• 2015

This study is an empirical study on the relationships among success factors of six sigma(support of top management, education and training, performance-based reward, customer and quality focused thought), job satisfaction, and quality performance. In particular, mediating effect of job satisfaction on the relationship between success factors of six sigma and quality performance is empirically analysed to find causes and impacts among these variables. A survey was conducted on the employees working in 'H' company which is applying six sigma at Ulsan City. The survey questionnaires were sent to 300 people and 216 of them were returned. Data obtained was analyzed with SPSS 18.0. The study results are as follows: First, there were positive relationships between critical success factors of six sigma(except support of top management) and job satisfaction. Second, there was also a positive relationship between job satisfaction and quality performance. Third, there were also positive relationships between critical success factors of six sigma(except support of top management) and quality performance. Finally, job satisfaction were full mediating effects on the relationship between critical success factors of six sigma(education and training, performance-based reward) and quality performance. Critical success factors of six sigma(customer and quality focused thought) had a partial mediating effect on quality performance. On the other hand, support of top management had no mediating effect on quality performance.

• Nuclear Engineering and Technology
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• v.39 no.4
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• pp.349-358
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• 2007

A single-beam gamma densitometer is utilized to measure the average void fraction in a small diameter stainless steel pipe under critical flow conditions. A typical design of a single-beam gamma densitometer is composed of a sealed gammaray source, a collimator, a scintillation detector, and a data acquisition system that includes an amplifier and a single channel analyzer. It is operated in the count mode and can be calibrated with a test pipe and various types of phantoms made of polyethylene. A good average void fraction is obtained for a small diameter pipe with various flow regimes of the core, annular, stratified, and bubbly flows. Several factors influencing the performance of the gamma densitometer are examined, including the distance between the source and the detector, the measuring time, and the ambient temperature. The void fraction is measured during an adiabatic downward two-phase critical flow in a vertical pipe. The test pipe has an inner diameter of 10.9 mm and a thickness of 3.2 mm. The average void fraction was reasonably measured for a two-phase critical flow in the presence of nitrogen gas.

• Proceedings of the Korean Nuclear Society Conference
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• 2004.05a
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• pp.228-228
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• 2004

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.1
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• pp.383-386
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• 2006

The safety of the railway system is important because the system is a mass transit system and the results of the accident are inconceivable. The railway system is operated by train operation system such as train control system. So the train control system requires safety critical characteristics. In the European railway, ETCS (European Train Control System) project has been finished to accomplish the interoperability of each national railway signaling system. According to the interoperability degree, ETCS levels are suggested. As the highest level, ETCS level 3 suggests a radio communication. Also recently urban railway system is operated by driverless and automatic train control system. In this circumstance, more safety is required than before in the railway system. In order to accomplish the safety of a system, the requirements considering safety have to be suggested. The requirement is a set of several functions such as general function, environment, safety etc. For the safety critical system, safety function is more important than any other functions. The safety functions are deduced by safety analysis. In order to perform the safety analysis, the system hazards have to be identified and then risk analysis for each hazard should be performed. The risk is related to the frequency and the severity of each hazard. And then countermeasures for each risk have to be prepared. The summary of the countermeasures is about a kind of safety functions in a system. In this paper, the safety functions for a train control system are presented according to the above procedure.

• Journal of Korea Multimedia Society
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• v.14 no.3
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• pp.440-448
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• 2011

The needs for the OpenGL-family of the rendering library standards are highly increasing, especially for the graphical human-machine Interface on the various systems including smart phones and personal information devices. Additionally, in the case of safety-critical market for avionics, military, medical and automotive applications, OpenGL SC, the safety critical profile of the OpenGL library plays the major role for the graphical interfaces. In this paper, we represent our OpenGL SC emulation library on the OpenGL 1.x rendering pipeline which is widely available on the existing embedded systems, to provide the features of OpenGL SC standard cost-effectively. Our method can provide the OpenGL SC features at the low development cost on the embedded systems, and its implementation is also one of the fundamental elements for the emulation of embedded systems in the PC environment. Our final result now works on both of Linux-based and VxWORKS systems, showing correct execution results at the reasonable speed.

• Journal of Advanced Navigation Technology
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• v.21 no.2
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• pp.155-162
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• 2017

In recent years, aviation-related safety-critical systems have been developed in Korea, but these products have not satisfied the specified requirements and thus have not been commercialized or commercialized. Due to increasing complexity of the modern aviation system, traditional verification and validation techniques are not sufficient to identify and reduce latent risks in the system. To overcome this shortcoming, a new method which is called 'Independent verification and validation (IV&V)' is suggested. However, academic researches on the effectiveness of this independent verification and validation have not been conducted domestically, and it is performed very rarely even overseas. Therefore, in this paper, we investigated the application of independent verification and validation of the safety-critical aviation systems performed by advanced aviation organizations, and analyzed various positive effects on projects. As a result of the analysis, IV&V shows that early error detection rate is increased, potential risk is mitigated early, and the complex reworking probability, which appears later in the development life cycle, is reduced, greatly preventing the development schedule and costs from increasing.

• Journal of Korean Society for Quality Management
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• v.41 no.4
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• pp.725-735
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• 2013

Purpose: The purpose of this study is to propose an Integrated Safety Evaluation Process (ISEP) that can enhances the safety aspect of the safety-critical system. This process utilizes the advantages of the iterative Systems Engineering process combined with the safety assessment process that is commonly and well defined in many standards and/or guidelines for railway, aerospace, and other safety-critical systems. Methods: The proposed process model is based on the predefined system lifecycle, in each phase of which the appropriate safety assessment activities and the safety data are identified. The interfaces between Systems Engineering process and the safety assessment process are identified before the two processes are integrated. For the integration, the elements at lower level of Systems Engineering process are combined with the relevant elements of safety assessment process. This combined process model is represented as Enhanced Functional Flow Block Diagram (EFFBD) by using CORE(R) that is commercial modelling tool. Results: The proposed model is applied to the lifecycle and management process of the United States aircraft system. The US aircraft systems engineering process are composed of twelve key elements, among which the requirements management, functional analysis, and Synthesis processes are considered for examplenary application of the proposed process. To synchronize the Systems Engineering process and the safety assessment process, the Systems Engineering milestones are utilized, where the US aircraft system has thirteen milestones. Taking into account of the nine steps in the maturity level, the integrated process models are proposed in some phases of lifecycle. The flows of processes are simulated using CORE(R), confirming the flows are timelined without any conflict between the Systems Engineering process and the safety assessment process. Conclusion: ISEP allows the timeline analysis for identifying activity and data flows. Also, the use of CORE(R) is shown to be effective in the management and change of process data, which helps for the ISEP to apply for the development of safety critical system. In this study, only the first few phases of lifecyle are considered, however, the implementation through operation phases can be revised by combining the elements of safety activities regarding those phases.

• Journal of Fisheries and Marine Sciences Education
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• v.25 no.5
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• pp.1055-1067
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• 2013

We attempted to apply the HACCP system adopted in the food industry to a olive flounder (Paralichthys olivaceus) aquaculture farm to ensure the hygiene safety of farmed fish. In this study, HACCP system procedures, including HACCP team organization, critical point determination, establishment of standard limits etc., were established using Codex 12 procedures. To determine whether hazards were critical elements, we evaluated the likelihood and seriousness of each hazard element. The likelihood of residual medicine exceeding the acceptable limit in shipped fish products was demonstrated to be a critical hazard element. Management of the shipment stage was determined to be a critical control point (CCP). Checking the records for stock and release and maintaining a history of medicine use before shipping the fish were suggested as monitoring methods. The standards for acceptable residual medicine were set based on relevant laws and regulations, and then the limits were adapted and established for the CCP. An HACCP plan applicable to olive flounder farms was established.

• Korean Journal of Community Nutrition
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• v.21 no.1
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• pp.84-92
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• 2016

Objectives: This study was performed to develop a food safety education program for school foodservice employees and evaluate its effectiveness. Methods: Food safety education programs were made into two levels; one for new employees in school foodservice and another for employees in charge of Critical Control Point (CCP) monitoring. The programs were for 40-minute-long lecture using PowerPoint. The effectiveness of these programs were assessed based on eleven evaluation items by school foodservice dieticians (n=30) and the Hazard Analysis Critical Control Point (HACCP) specialist (n=13). All statistical analyses are conducted by SPSS package program (ver 20.0). Results: According to the results of evaluating the food safety education program by dietitian and HACCP specialist, the overall satisfaction score was 4.14, evaluated by 5 point scale. There were no significant difference in results of evaluation between dieticians and HACCP specialists. The score of 'it is helpful to work' and 'pictures, images and charts are pertinent to study' were higher than others while the score of 'education contents is pleasant and interesting' and 'screen is pleasant and interesting' were the lowest among all evaluation items. Conclusions: To increase the school foodservice quality, employees should be offered regular food safety education and training through effective education media including prerequisite program and HACCP manual for school foodservice.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.343-352
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• 2008

Safety-critical systems related to the railway communications are currently undergoing changes. Mechanical and electro-mechanical devices are being replaced by programmable electronics that are often controlled remotely via communication networks. Therefore designers and operators now not only have to contend with component failures and user errors, but also with the possibility that malicious entities are seeking to disrupt the services provided by theirs systems. Recognizing the safety-critical nature of the types of communications required in rail control operations, the communications infrastructure will be required to meet a number of safety requirements such as system faults, user errors and the robustness in the presence of malicious attackers who are willing to take determined action to interfere in the correct operation of a system. This paper discusses the safety strategies employed in the railway communications and proposes a security mechanism for Korean railway communication system. We present the developed communication safety evaluation tool based on the proposed security mechanism and also evaluate its protecting capability against the threats of masquerading, eavesdropping, and unauthorized message manipulation.