• Journal of Advanced Marine Engineering and Technology
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• v.25 no.6
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• pp.1308-1316
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• 2001

This paper described a numerical investigation performed to understand better the effects of flow parameters in an entrained flow combustor on the flow characteristics. The computational model was based on the gas phase Eulerian equations of mass, momentum and energy. The code was formulated with RNG $k-\varepsilon$ model for turbulent flow. The calculation parameters were the ratio of primary and secondary jet velocity and the height difference between primary and secondary jet As the secondary jet velocity increased, the upper recirculation 3one of the primary jet was strengthened. It was found that as the primary jet velocity increased, there was a critical jet Velocity at which the size of upper and lower recirculation zone was reversed.

• Journal of Advanced Marine Engineering and Technology
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• v.27 no.6
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• pp.696-703
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• 2003

A photovoltaic power generation system is an infinite and clean energy system. Recently. because of the realization of high efficiency and low cost PV modules, the studies on the PV system have extensively increased. In this paper. we present an online scheme for parameter estimation of solar cell, based on the model adjustment technique and a real-coded genetic algorithm(RCGA). The ideal diode model and the diode model with series and shunt resistors are used to estimate their parameters, Simulation works using field data in the form of a V-I characteristic curve are carried out to demonstrate the effectiveness of the proposed method.

• Journal of Advanced Marine Engineering and Technology
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• v.24 no.6
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• pp.102-109
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• 2000

In this industrial induction motor speed and torque controlled drive system, the closed loop control usually requires the measurement of speed or position of amotor. However a sensorless drive of an induction motor has several advantages ; low cost and mechanical simplicity. Thus this paper investigates a field oriented control method without speed and flux sensors. The proposed control strategy is based on the Model Reference Adaptive System(MRAS) using a new flux estimator which replaces integrators with two lag circuits as the reference model. This algorithm may overcome several shortages of conventional MRAS such as integrator problems, small EMF at low speed. The simulation and experimental results indicate good speed responses.

• Journal of Advanced Marine Engineering and Technology
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• v.23 no.2
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• pp.216-225
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• 1999

Four turbulent $k-{varepsilon}$models(i.e standard model modified models with streamline curvature modification and/or preferential dissipation modification) are applied in order to analyze the tur-bulent flow of wall-attaching offset jet. The upwind numerical scheme was adopted in the present analyses. The streamline curvature modification results in slightly better prediction while the preferential dissipation modification does not. The obtained analytic results will be used as refer-ences for further study regarding Reynolds stress model. In addition this paper introduced a method of increasing nozzle outlet velocity gradually for numercal convergence. Even though the method was simple it was efficient in view of convergent speed CPU running time computer memory storage programming etc.

• Journal of Advanced Marine Engineering and Technology
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• v.18 no.4
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• pp.33-42
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• 1994

The radiative heat transfer analysis in the fluidized particles layer has important application in many technological areas such as combustion chambers at high pressure and temperature, plasma generators for nuclear fusion, MHD generator using pulverized coal and the liquid droplet radiator used to reject wasted heat from a power plant operating in space. To accurately model the radiation properties of the fluidized particles layer, it is necessary to know the radiation interchange factors of particles in each layer. But the solutions are usually not possible for the equations of radiative heat transfer because it has an inherent difficulty in treating the governing intergo- differential equations, which are derived from the remote effects of radiative heat transfer. In this study, the analysis uses the Monte Carlo simulation method with optical depth model to calculate the radiation interchange factors of particles in each layer with wall and with each other.

• Journal of KIISE:Software and Applications
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• v.36 no.5
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• pp.386-395
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• 2009

Business entities with which most service components interact are kind of cross-cutting concerns in a multi-layered distributed application architecture. When business entities are modified, service components related to them should also be modified, even though they implement common functions of the application framework. This paper proposes what we call DTT (Data Type-Tolerant) component model to process the variability of business entities, or externalized data, which feature modern application architectures. The DTT component model expresses the data variability of product lines at the implementation level by means of SCDTs (Self-Contained Data Types) and variation point interfaces. The model improves the efficiency of application engineering through data type converters which support type conversion between SCDTs and business entities of particular applications. The value of this model lies in that data and functions are coupled locally in each component again by allowing service components to deal with SCDTs only instead of externalized business eutities.

• Journal of Advanced Marine Engineering and Technology
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• v.40 no.6
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• pp.535-541
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• 2016

In this paper, we analyzed efficient decoding scheme with FTN(Faster than Nyquist) method that is transmission method faster than Nyquist theory and increase the throughput. Applying the FTN method to satellite and underwater communication, we proposed an efficient transceiver model. To minimize ISI(Inter-Symbol Interference) induced by FTN signal, turbo equalization algorithms that iteratively exchange probabilistic information between Viterbi equalizer based on BCJR algorithm and LDPC decoder are used in satellite communication. In others, for underwater communication, DFE equalizer and LDPC decoder are concatenated to improve performance.

• Convergence Security Journal
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• v.12 no.4
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• pp.25-31
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• 2012

The SSE-CMM model is how to verify the level of information protection as a process-centric information security products, systems and services to develop the ability to assess the organization's development. The CMM is a model for software developers the ability to assess the development of the entire organization, improving the model's maturity level measuring. However, this method of security engineering process improvement and the ability to asses s the individual rather than organizational level to evaluate the ability of the processes are stopped. In this research project based on their existing research information from the technical point of view is to define the maturity level of protection. How to diagnose an information security vulnerabilities, technical security system, verification, and implementation of technical security shall consist of diagnostic status. The proposed methodology, the scope of the work place and the current state of information systems at the level of vulnerability, status, information protection are implemented to assess the level of satisfaction and function. It is possible that measures to improve information security evaluation based on established reference model as a basis for improving information security by utilizing leverage.

• Journal of the Korean Society of Systems Engineering
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• v.15 no.2
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• pp.79-86
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• 2019

Among the government-sponsored projects supported by Ministry of SMEs and Startups(MSS), the financial support of the Consulting Research Institutes of our university is scheduled to be ended this year. In this regard, this study is to develop a profit model for R&D center of Consulting Research Institute that can cultivate the financial independence of R&D center of Consulting Research Institutes and foster technology convergence consulting manpower to strengthen the competitiveness of SMEs in preparation for the Fourth Industrial Revolution. The profit model were derived from the current status of consulting industry and similar organizations, the current status of consulting graduate R&D centers, case studies of other universities, and focus group interviews. In order to select three high profit models and commercialize them, BMC (Biz Model Canvas) was used and business feasibility was examined. Therefore, three profit model of R&D center of Consulting Research Institute are: First, SCB (SME's Consulting Business: Total Solution Provider for SMEs through Technology Convergence Consulting), Second, SNB (SME's Network Business: Experts connection in Consulting Graduate School for Solving Problems and Problems of SMEs / Industry Consolidation) And third, SM (Sustainable Management: Financial independence through structural improvement of Consulting Research Institute), and the road-map was established. As an implementation plan, the company intends to seek financial independence by developing a profit model for R&D center of Consulting Research Institutes and by establishing business goals and strategies, manpower operation plan, organization, and investment plan for three years.

• Fire Science and Engineering
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• v.24 no.5
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• pp.87-93
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• 2010

The fact that the smoke hinders evacuation and fire-fighting activities as well as becomes the major cause of life casualty emphasizes the importance of smoke control system. As one of the fire safety standards designed to secure the smoke safety, NFSC501A (Design Guide for Smoke Control System of Special Evacuation Stairwell and Lobby) has been proposed, preventing smoke from penetrating into the smoke-free escape route by raising the pressure of the smoke control zone higher than fire area. For model building of 20 stories, pressurization system was designed according to standard and pressure field of compartments in whole building induced by pressurization system was analyzed using the network model.