• Transactions of the Korean Society of Mechanical Engineers
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• v.15 no.2
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• pp.668-676
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• 1991

Turbulent flows around tube banks and in the diffuser were studied using a non-orthogonal boundary fitted coordinate system and the modified K-.epsilon. turbulence model. In these cases, many problems emerge which stem from the geometrical complexity of the flow domain and the physical complexity of turbulent flow itself. To treat the complex geometry, governing equations were reformulated in a non-orthogonal coordinate system with Cartesian velocity components and discretised by the finite volume method with a non-staggered variable arrangement. The modified K-.epsilon. model of Hanjalic and Launer was applied to solve above two cases under the condition of strong and mild pressure gradient. The results using the modified K-.epsilon. model results in both test cases.

• Proceedings of the KIPE Conference
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• 2000.07a
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• pp.464-467
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• 2000

In this paper we introduce the network based multi-motors control system using CAN(Controller Area Network) The traditional multi-motors control system has many problems in the view of reliability and economy because of the amount and complexity of wiring noise and maintenance problems etc, These problems are serious especially when the motor controllers are separated widely CAN is generally applied in car networking in order to reduce the complexity of the related wiring harnesses. These traditional CAN application techniques are modified to achieve the real time communication for the multi-motor control system. And also the position synchronization technique is developed and the proposed methods are verified experimentally.

• Journal of KSNVE
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• v.1 no.1
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• pp.45-52
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• 1991

The dynamic properties of primary-secondary structural systems are examined using analytical expressions for the modal properties. The analysis begins with a Lagrange multiplier formulation to develop a characteristic equation in terms of primary system mobilities and secondary system impedances. The complexity of the characteristic equation by developing new method, frequency window method. It is shown that the reduction of complexity can only be obtained by a reduction of accuracy, but by retaining the dominant effects of the dynamics problem, the loss of accuracy is not excessive. The reduced problem is examined further to develop simple expressions for the modal properties which provide insight into the resonance characteristics of the primary-secondary system problem. The results are useful as a complement to existing computational techniques for understanding and interpreting dynamic analysis results.

• IEMEK Journal of Embedded Systems and Applications
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• v.5 no.3
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• pp.128-135
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• 2010

Recently complexity of embedded software cause to be used real-time operating system (RTOS) to implement various functions in the embedded system. And also, according to requirement of complex functions in embedded systems, the number as well as complexity of tasks get increased continuously. In case that many tasks collaborated in a microprocessor, context switching time between tasks is a overhead waisting a CPU resource. Therefore the time of task context switching is an important factor that affects performance of RTOS. In this paper, we concentrate on the improvement of task context switch for reducing overhead and achieving fast response time in RTOS. To achieve these goal, we suggest multiple register files and task context switching algorithm. By reducing the context switch overhead, we try to ease scheduling and assure fast response times in multitasking environment. As a result, the context switch overhead decreased by 8~16% depend on the number of register files, and some task set which are not schedulable with single register file are schedulable due to that decrease with multiple register files.

• Journal of Information Technology Applications and Management
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• v.17 no.3
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• pp.191-211
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• 2010

Existing models of knowledge processing do not feature a systemic meaning of knowledge management and ignore the role of leadership and social energy in the knowledge processing system (KPS). This conceptual paper introduces the Leadership Invigorating Flows of Energies, (LIFE) Model as an attempt to remedy that situation and provide a more useful description of the KPS. The LIFE Model highlights the role of emergent leadership and flows of social energies as forces encouraging knowledge creation and dynamic diffusion within an organization through the Knowledge Processing Cycle in eight activities interacting with its social knowledge base in a self-organizing system.

• Korean System Dynamics Review
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• v.5 no.1
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• pp.99-110
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• 2004

Building trust assurance particularly in case of commercial practices in cyber space without physical contact is a very complex task to tackle. Several factors are interrelated in not necessarily technical but also societal dimensions over the entire process of e-commerce firm ex-ante through ex-post transactions. This paper attempts first to brief the substance of e-trust and examine the natuure of its complexity by using system dynamics simulation technique, followed by its current address and the future directions to move. A framework of 3 x 3 matrixes is deviaed and the key issues of e-trust are mapped into cross-cells of the table. The paper also includes some possible suggestions on the matter of trust assurance especially for B2C and B2B in policy wise and organizational perspective from the context of international collaboration.

• Journal of information and communication convergence engineering
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• v.4 no.2
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• pp.75-78
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• 2006

This work presents a low complexity maximum-likelihood decoder for signal detection in VBLAST-STBC system, which employs non-square O-STBC code rate 3/4. Stacking received symbols from different symbol duration and applying QR decomposition result in the special format of upper triangular matrix R so that the proposed decoder is able to provide not only ML-like BER performance but also very low computational load. The low computational load and ML-like BER performance properties of the proposed decoder are verified by computer simulations.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.34-34
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• 2000

One of the basic goals, when considering networks for communication in industrial control applications, is the reduction of complexity of related wiring harnesses. In addition, the networking offers the advantages for industrial control applications, such as ease of cabling, ease of changes in the cabling, ease of adding controller modules, etc. CAN (Controller Area Network) is generally applied in car networking in order to reduce the complexity of the related wiring harnesses. These traditional CAN application techniques are modified to achieve the real time communication for the industrial control applications. In this paper, we propose the method of CAN Identifier assignment for Real-Time network system. This method is can be used to scheduling messages on CAN for Real-Time network system. And also, the real-time network system is developed and the proposed moth(Ids are verified experimentally.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.10B
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• pp.1793-1802
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• 2000

In this paper we propose an efficient implementation technique for cyclic extension in VDSL(Very High bit-rate Digital Subscriber Line) systems using Zipper duplexing and analyze its performances under typical telephone channel environments. In Zipper-based VDSL systems each DTM(discrete-multitone) block is appended by both cyclic prefix(CP) and cyclic suffix(CS). The CP is inserte to prevent both intersymbol interference (ISI) and iterchannel interference (ICI) while the CS is appended to ensure orthogonality between the upstream and downstream carriers thus preventing near-end crosstalk (NEXT). However in order to implement the CP in the transmitter side of the VDSL system an additional hardware is required to append the latter part of each DMT symbol to the beginning of the DMT symbol. In this paper we propose a VDSL system with Zipper duplexing using only CS to reduce hardware complexity (memory and processing delay) required for implementation of CP. It is shown by computer simulation that the proposed approach has the same capacity under typical channel environments as the previous Zipper-based VDSL system using both CP and CS. even with a significantly lower hardware complexity.

• Journal of the Ergonomics Society of Korea
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• v.32 no.5
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• pp.429-435
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• 2013

Objective: This study aims to analyze job satisfaction and accident prevention according to job rotation system types in a motor company. Background: The study of a motor company's job rotation system has come to attention with enhancing productivity, preventing musculoskeletal disorders, and improving quality. Method: In this study, a survey was conducted to show job satisfaction rates according to job rotation systems. Also an investigation was done regarding industrial accidents and previous workers who are receiving treatment for musculoskeletal disorder over the last five years. Results: The job rotation system in this study has been carried out by voluntary decision of workers. Out of the job rotation types, the medium rotation complexity type had high job satisfaction whereas in a high or low rotation complexity type, which many workers prefer, led to less number of accidents and days of sick leave. Application: The results of this study are expected to be a fundamental data to job design.