• Transactions of the Korean Society of Mechanical Engineers A
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• v.30 no.4 s.247
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• pp.442-450
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• 2006

This paper describes the new modal analysis method to detect the presence of the breathing crack in a general rotor system with disk asymmetry and stator anisotropy. It is proposed that the modal analysis using directional frequency response functions (dFRFs), which, accounting for the directivity in modes, clears the heavily over-lapping of other harmonics occurring from non-isotropic properties in addition to those due to crack, can provide an effective method to detect the modes by a crack. The simulations from the simple general rotor model show that the r-dFRFs (reverse dFRFs) for asymmetry confirms a good indicator of the presence of the breathing crack and the instability is primarily influenced by the shaft asymmetry than the breathing crack.

• Journal of the Korea Safety Management & Science
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• v.4 no.4
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• pp.97-108
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• 2002

This study deals with the application of knowledge-based engineering and a methodology for the assessment & measurement of reliability, availability, maintainability, and safety of industrial systems using fault-tree representation. A fuzzy methodology for fault-tree evaluation seems to be an alternative solution to overcome the drawbacks of the conventional approach. To improve the quality of results, the membership functions must be approximated based on heuristic considerations. Conventionally, it is not always easy to obtain a system reliability for components with different individual failure probability density functions(p.d.f.), We utilize fuzzy set theory to solve the adequacy of the conventional probability in accounting and processing of built-in uncertainties in the probabilistic data. The purpose of this study is to propose the framework of knowledge-based engineering through integrating the various sources of knowledge involved in a FTA.

• Journal of Korean Society of Steel Construction
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• v.15 no.6 s.67
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• pp.661-672
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• 2003

The advanced analysis and optimal design of semi-rigid frame were presented. Advanced analysis can predict the combined nonlinear effects of connection, geometry, and material on the behavior and strength of semi-rigid frames. The Kishi-Chen power model was used to describe the nonlinear behavior of semi-rigid connections. Geometric nonlinearity was determined using stability functions. On the other hand, material nonlinearity was determined using the Column Research Council (CRC) tangent modulus and parabolic function. The direct search method proposed by Choi and Kim was used as optimization technique. The member with the largest unit value evaluated using the LRFD interaction equation was replaced one by one with an adjacent larger member selected from the database. The objective function was assumed as the weight of steel frame, with the constraint functions accounting for load-carrying capacities, deflections. inter-story drifts, and ductility requirement. Member sizes determined by the proposed method were compared with those derived using the conventional LRFD method.

• ETRI Journal
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• v.25 no.5
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• pp.387-400
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• 2003

Since its launching on 21 December 1999, the Korea Multi-Purpose Satellite-I (KOMPSAT-I) has been successfully operated by the Mission Control Element (MCE), which was developed by the ETRI. Most of the major functions of the MCE have been successfully demonstrated and verified during the three years of the mission life of the satellite. This paper presents the operational performances of the various functions in MAPS. We show the performance and analysis of orbit determinations using ground-based tracking data and GPS navigation solutions. We present four instances of the orbit maneuvers that guided the spacecraft form injection orbit into the nominal on-orbit. We include the ground-based attitude determination using telemetry data and the attitude maneuvers for imaging mission. The event prediction, mission scheduling, and command planning functions in MAPS subsequently generate the spacecraft mission operations and command plan. The fuel accounting and the realtime ground track display also support the spacecraft mission operations.

• Structural Engineering and Mechanics
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• v.57 no.6
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• pp.1065-1084
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• 2016

The analysis and design of skeletal structures is greatly influenced by the behaviour of beam-to-column connections, where patented designs have led to a wide range of types with differing structural quantities. The behaviour of beam-to-column connections plays an important role in the analysis and design of framed structures. This paper presents an overview of the influence of connection behaviour on structural stability, in the in-plane (bending) mode of sway. A computer-based method is presented for geometrically nonlinear plane frames with semi-rigid connections accounting for shear deformations. The analytical procedure employs transcendental modified stability functions to model the effect of axial force on the stiffness of members. The member stiffness matrix were found. The critical load has been searched as a suitable load parameter for the loss of stability of the system. Several examples are presented to demonstrate the validity of the analysis procedure. The method is readily implemented on a computer using matrix structural analysis techniques and is applicable for the efficient nonlinear analysis of frameworks. Combined with a parametric column effective length study, connection and frame stiffness are used to propose a method for the analysis of semi-rigid frames where column effective lengths are greatly reduced and second order (deflection induced) bending moments in the column may be distributed via the connectors to the beams, leading to significant economies.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.4
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• pp.795-802
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• 2010

Currently, the business environment has been rapidly changed due to the fast globalization and development of information technology. Therefore, many companies are trying to change their management system by improving their own decision making systems and innovations. Many domestic enterprises are introducing or considering the ERP system. In the field of ERP management accounting, there are many auxiliary functions for helping efficient internal management analysis for company. In this paper, we proposed and developed an improved method for minimize the variance between standard cost and actual cost of materials of the company. In this method we proposed efficient ERP cost management system considering current cost component including currency and actual material cost and overhead costs.

• The Journal of Asian Finance, Economics and Business
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• v.7 no.3
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• pp.265-276
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• 2020

The study aims to explore the problems of the existing Shariah Governance Framework (SGF) and its concerned authorities in the context of Bangladesh. Thus, according to responses from 17 respondents, this study outlines that Bangladesh has an absence of a shortage of experts, experienced, knowledgeable, and qualified Shariah people at all levels (i.e., the central bank, Islamic banks, Shariah Supervisory Boards (SSBs), and regulators). Therefore, Bangladesh does not have a separate Islamic banking act, Shariah audit firm, Shariah index institutions, and comprehensive SGF. The existing guideline has a limitation concerning its comprehensiveness, accountability, responsibility, and structure of SSBs. Islamic banks do not follow the instruction of the central bank in the formation of SSBs. As a result, there is an absence of competent and qualified SSB, which also results in the functions of Shariah departments as well as Shariah applications. Usually, the Board of Directors (BOD), management, executives, customers, and the public also have the conceptual gap about Islamic banks, SGF, and banking system compared to the regular prayers, faith, and belief. Concisely, Bangladesh requisites a comprehensive SGF, Islamic banking act, a standard accounting system, and a robust Shariah audit system for the overall development of Islamic banks and SGF.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.6 no.1
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• pp.144-155
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• 1996

During the 1990s the workplace has grown more complex and business competition has increased world-wide. All organizations, whether for-profit or non-profit have been forced to respond to market changes. More advanced information and technology, greater product diversity, shorter product life cycles, increased quality requirements, more regulation oversight, decreasing productivity, more competitors, and increasing overhead costs have motivated organizations to focus on ways to deliver products cheaper, better, and faster. Many organizations are searching for ways to reduce costs through downsizing, reengineering business processes, implementing quality management, outsourcing, and improving cost management. Support departments that provide services internal to an organization such as human resources, legal, and environmental, safety, and health (ES&H) are often the first organization targeted for cost reduction and cost control initiatives because these functions are part of a rapidly increasing overhead cost. Recently, ES&H functions are incresingly being integrated into the business of business to contribute value to organization beyond mere compliance with ES&H regulations. The discussions and development of the ISO compatible Environmental Management Standards or Occupational Safety and Health Management Standards is another impetus to integrate ES&H function into the business of business. Thus, ES&H professional need new skills to analyze the cost of their function and communicate the value of the products and services they provide. In recent years, the need for and the importance developing cost management and business skills by ES&H professionals have been emphasized in the literature. Communicating with decision makers in terms of cost and value to the organization, and by using business language and business arguments is the first step toward effectively integrating ES&H activities into the business of business. Activity-based costing (ABC) is a cost management method that measures the cost of a product or service based on the actual use of resources by activities, and based on the actual amount of activities used to produce a product or service. ABC is recommended as a tool for managers of ES&H organizations to determine the cost of developing and providing ES&H products within a for-profit firm or non-profit agency. This paper discusses the trend of integration of ES&H functions into the mainstream of business activities within an organization. The general principles of treditional cost accounting are presented as a bases for understandging why and how ABC will provide more accurate estimates of cost. The principles and concepts of ABS are presented as a tool for determining more accurately the true cost of ES&H products and services.

• International Journal of Highway Engineering
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• v.11 no.1
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• pp.187-194
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• 2009

This paper presents the development of transfer function accounting for cross-anisotropic behavior of aggregate base material for the pavement thickness design. The stress distributions predicted by nonlinear cross-anisotropic finite element program were realistic by eliminating excessive tensile stress at the bottom of the base layer and the critical pavement responses predicted by nonlinear cross-anisotropic model are higher than those predicted by linear or nonlinear isotropic models (Kim, 2004, Kim et at., 2005). Since the previously developed transfer functions such as Asphalt Institute and Chevron models, etc. were based on the critical responses obtained from linear isotropic model, those equations are not appropriate for the thickness design nonlinear cross-anisotropic base behavior. Therefore, the development of usable transfer functions for nonlinear cross-anisotropic model is ever more important. When the newly developed transfer functions were compared with AASHTO method for the thickness design, the newly developed transfer functions produce approximately 25mm reduced UAB thickness in AASHTO thickness design and this illustrates that linear isotropic model results in more conservative pavement design.

• Ocean Systems Engineering
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• v.9 no.3
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• pp.287-328
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• 2019

Comprehensive understanding of the flood risk assessments via frequency analysis often demands multivariate designs under the different notations of return periods. Flood is a tri-variate random consequence, which often pointing the unreliability of univariate return period and demands for the joint dependency construction by accounting its multiple intercorrelated flood vectors i.e., flood peak, volume & durations. Selecting the most parsimonious probability functions for demonstrating univariate flood marginals distributions is often a mandatory pre-processing desire before the establishment of joint dependency. Especially under copulas methodology, which often allows the practitioner to model univariate marginals separately from their joint constructions. Parametric density approximations often hypothesized that the random samples must follow some specific or predefine probability density functions, which usually defines different estimates especially in the tail of distributions. Concentrations of the upper tail often seem interesting during flood modelling also, no evidence exhibited in favours of any fixed distributions, which often characterized through the trial and error procedure based on goodness-of-fit measures. On another side, model performance evaluations and selections of best-fitted distributions often demand precise investigations via comparing the relative sample reproducing capabilities otherwise, inconsistencies might reveal uncertainty. Also, the strength & weakness of different fitness statistics usually vary and having different extent during demonstrating gaps and dispensary among fitted distributions. In this literature, selections efforts of marginal distributions of flood variables are incorporated by employing an interactive set of parametric functions for event-based (or Block annual maxima) samples over the 50-years continuously-distributed streamflow characteristics for the Kelantan River basin at Gulliemard Bridge, Malaysia. Model fitness criteria are examined based on the degree of agreements between cumulative empirical and theoretical probabilities. Both the analytical as well as graphically visual inspections are undertaken to strengthen much decisive evidence in favour of best-fitted probability density.