• Nuclear Engineering and Technology
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• v.54 no.3
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• pp.896-908
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• 2022

As a part of probabilistic risk (or safety) assessment (PRA or PSA) of nuclear power plants (NPPs), the primary role of human reliability analysis (HRA) is to provide credible estimations of the human error probabilities (HEPs) of safety-critical tasks. In this regard, it is vital to provide credible HEPs based on firm technical underpinnings including (but not limited to): (1) how to collect HRA data from available sources of information, and (2) how to inform HRA practitioners with the collected HRA data. Because of these necessities, the U.S. Nuclear Regulatory Commission and the Korea Atomic Energy Research Institute independently developed two dedicated HRA data collection systems, SACADA (Scenario Authoring, Characterization, And Debriefing Application) and HuREX (Human Reliability data EXtraction), respectively. These systems provide unique frameworks that can be used to secure HRA data from full-scope training simulators of NPPs (i.e., simulator data). In order to investigate the applicability of these two systems, two papers have been prepared with distinct purposes. The first paper, entitled "SACADA and HuREX: Part 1. The Use of SACADA and HuREX Systems to Collect Human Reliability Data", deals with technical issues pertaining to the collection of HRA data. This second paper explains how the two systems are able to inform HRA practitioners. To this end, the process of estimating HEPs is demonstrated based on feed-and-bleed operations using HRA data from the two systems.

• Proceedings of the KIEE Conference
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• 2007.10c
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• pp.10-13
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• 2007

System requirements (SRs), which describe the technical attributes to be satisfied by a desired system, serve as a fundamental guideline for system development. Standard methods and processes to define SRs are suggested in systems engineering literature. But in practice, we encounter many difficulties in defining and managing SRs since there are few experiences on development of complex systems in accordance with systems engineering processes of development. In this paper, to expanding SRs management experiences in a working-level, we reviewed problems occured in SRs defining process in 'Urban MAGLEV Train Project', and analyzed our activities to adjust and solve the problems.

• International Journal of Control, Automation, and Systems
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• v.5 no.2
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• pp.170-183
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• 2007

This paper presents a delay-dependent approach to robust filtering for linear parameter-varying (LPV) systems with discrete and distributed time-invariant delays in the states and outputs. It is assumed that the state-space matrices affinely depend on parameters that are measurable in real-time. Some new parameter-dependent delay-dependent stability conditions are established in terms of linear matrix inequalities (LMIs) such that the filtering process remains asymptotically stable and satisfies a prescribed $H_{\infty}$ performance level. Using polynomially parameter-dependent quadratic (PPDQ) functions and some Lagrange multiplier matrices, we establish the parameter-independent delay-dependent conditions with high precision under which the desired robust $H_{\infty}$ filters exist and derive the explicit expression of these filters. A numerical example is provided to demonstrate the validity of the proposed design approach.

• Transactions of the KSME C: Technology and Education
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• v.1 no.1
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• pp.139-145
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• 2013

Light rail transit(LRT) is a public transportation and mainly has an automatic driverless operation system. LRT project is a large scaled project which a construction cost is tens of billions of won per km. Systems engineering(SE) is an interdisciplinary approach and means to enable realization of successful systems. In this paper, we propose the systems engineering processes and their outputs list for the LRT project. And then, we present template and sample case of process output. We also present a case which carried out SE process by SE tool.

• Journal of the Korean Society for Precision Engineering
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• v.31 no.3
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• pp.189-197
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• 2014

Diffractive optical elements (DOEs) - in general a complex pattern of micro- and nano-scale structures - can modulate and transform light in a predetermined way. Their importance is being increased nowadays because they can be designed to handle a number of simultaneous tasks. In view point of machining DOEs, it is a big challenge to fabricate micro- and nano-scale structures on a free-form surfaces. In this paper, the state-of-the-art of the ultra-precision machine tools is reviewed. Also some technical issues which determine the machine tool accuracy are discussed.

• Journal of Engineering Education Research
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• v.9 no.2
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• pp.52-70
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• 2006

Systems Engineering(SE), as a special discipline evolved from multidisciplinary and interdisciplinary design knowledges and practical lessons learned from development practices, is required to develop today's ever-growing large complex systems. As computer speed and analytic sophistication accelerate their applications, modern society's needs have become increasingly varied and complex. Rapid advances in Systems Engineering and its education programs among the developed countries demonstrate their needs as an alternative to what is lacking from traditional disciplinary engineering to meet new challenges of our changing social environments. Systems Engineering is an interdisciplinary approach that includes both management and technical processes. Its processes, methods, and tools are used to evolve, define, and verify an integrated, life-cycle balanced set of system solution that satisfy customer needs and requirements. The process methodology offers a top-down comprehensive, iterative and recursive problem solving process which includes the stating the problems, investigating the alternatives, architecting and modeling the system, integrating and operating the system, assessing and re-evaluating the system performances. The purpose of this paper is to research the cases of SE educational programs for both domestic and other developed countries and to propose recommendations for the domestic SE educational programs in the future.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.16 no.3
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• pp.208-215
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• 2016

The lithography hotspot detection process is crucial for semiconductor design development process. But, the lithography hotspot detection using optical simulation method takes much time and it slowdown the layout design development cycle. Though the geometry based approach is introduced as an alternative, it still revealed low detection performance and sophisticated framework. To solve this problem, we introduce a deep convolutional neural network based hotspot detection method. Our method made better results in ICCCAD 2012 dataset. To reach this score, we used lots of technical effort to improve the result in addition to just utilizing the nature of convolutional neural network. Inspection region reduction, data augmentation, DBSCAN clustering helped our work more stable and faster.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.21 no.45
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• pp.33-45
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• 1998

The typical characteristic of PDM(Product Data Management) System seperates the databases to store the meta data and applications. Therefore, meta data contains the information for the location of file, user profiles, relationships between the files, and process. PDM utilizes these information efficiently and does file management, configuration management, and process management. In this view, the integration strategy of PDM is to merge data and process. In the view of architecture, the interface between data and application and the actions of each application execute seamlessly. This architecture is viewed as integrated data and process among enterprises and implemented with client/server technology in distributed process environment that interfaced with open object-oriented technology which is developed with business object in the object-oriented infrastructure. In this paper, we studied the definition, function, and scope of PDM and researched the core technologies to implement the PDM integration environment. We also researched the PDM utilization in distributed enterprise environment and implementation of PDM integration environment with this technical background.

• Journal of the Korean Society of Systems Engineering
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• v.3 no.2
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• pp.17-24
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• 2007

The HEMU-400X(High-speed Electric Multiple Unit 400km/h eXperiment) project starts in 2007. It is required to control and balance the systems engineering activities throughout the project life cycle for a successful completion of the project. The Systems Engineering Management Plan(SEMP) is the primary, top level technical management document for the integration of all engineering activities within the context of, and as an expansion of, the project plan. A SEMP should be prepared for each project and regularly updated as development progresses. This paper proposes the systems engineering management plan for the HEMU-400X project.

• Coupled systems mechanics
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• v.2 no.1
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• pp.23-51
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• 2013

An analytical algorithm for the estimation of the resistance forces exerted on the dipper of a cable shovel and the specific energy consumed in the cutting-loading process is presented. Forces due to payload and to cutting of geomaterials under given initial conditions, cutting trajectory of the bucket, bucket's design, and geomaterial properties are analytically computed. The excavation process has been modeled by means of a kinematical shovel model, as well as of dynamic payload and cutting resistance models. For the calculation of the cutting forces, a logsandwich passive failure mechanism of the geomaterial is considered, as has been found by considering that a slip surface propagates like a mixed mode crack. Subsequently, the Upper-Bound theorem of Limit Analysis Theory is applied for the approximate calculation of the maximum reacting forces exerted on the dipper of the cable shovel. This algorithm has been implemented into an Excel$^{TM}$ spreadsheet to facilitate user-friendly, "transparent" calculations and built-in data analysis techniques. Its use is demonstrated with a realistic application of a medium-sized shovel. It was found, among others, that the specific energy of cutting exhibits a size effect, such that it decreases as the (-1)-power of the cutting depth for the considered example application.