• Journal of the military operations research society of Korea
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• v.16 no.2
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• pp.135-150
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• 1990

This paper classifies faults into three types : simple, degenerated, and regenerated faults. This paper also deals with the characteristics of each type of fault to determine the software reliability based on the assumption; i. e., a system consisting of several subsystems (modules) which may be debugged simultaneously. For each type of fault, several formulas are developed to obtain the failure rate and the expected number of failures found during debugging. A model is developed based on the formulas of the failure rate and the expected number of failures to decide the optimal release time of a new software: minimizing the total cost with constraints restricting to the failure rate of each module in the software. By using this model, optimal release times are found for some cases; the eliminated faults are assumed simple faults only, regenerated faults only, simple and degenerated faults, and so on.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.3
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• pp.424-430
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• 2013

This paper presents a new design works for the braking chopper system which is included in the propulsion system of KTX high speed train. Due to the current fed type synchronous motors used in the propulsion system, some different behaviors are shown comparing to the voltage type other chopper systems. Specially this chopper system acts either braking controlling or regenerative power controlling system with a parallel resistive load in the propulsion system. In this paper, an improved simple high power IGBT brake chopper system has proposed which is able to be replaced with an existing complicated GTO chopper system. The analytical approaches to the parallel load type current chopper system and the propper snubber circuits calculation were explained in this paper to control new chopper system. In addition, the thermal resistance of the cooling system for power dissipation of IGBT modules was calculated also. Finally several PC simulations have been done to clarify its availability.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1995.04a
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• pp.79-90
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• 1995

The material handling equipment selection, that is a key task in the material handling system design, is a complex, difficult task, and requires a massive technical knowledge and systematic analysis. It is invaluable to justify the selected equipment model by the performance evaluation before its actual implementation. This paper presents an intelligent knowledge-based expert system called "IMESE" created by authors, for the selection and evaluation of material handling equipment model suitable for movement and storage of materials in a manufacturing facility. The IMESE is consisted of four modules: a knowledge base to select an appropriate equipment type, a multiple criteria decision making procedure to choose the most favorable commercial model of the selected equipment type, a database to store the list of commercial models of equipment types with their specifications, and simulators to evaluate the performance of the equipment model. The whole process of IMESE is executed under VP-Expert expert system environment.vironment.

• Journal of Advanced Marine Engineering and Technology
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• v.32 no.6
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• pp.915-922
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• 2008

The gas separation technology using membrane is widely used to refine various gases in many industry fields and recently is being applying in $CO_2$ recovery technology. In the gas and chemical tanker. nitrogen generators for inerting, purging and padding are on board and most of them have membrane modules of hollow fiber type with long life and vibration resisting properties. Because a membrane module is a key component accounting for 50% of total manufacturing cost of nitrogen generator, adequate selection for it is an important problem. In this paper, the flow performance coefficient based on dimension and specification data of membrane module was relatively selected to compare nitrogen generating capacity of module and various performance tests about the selected PARKER ST6010 membrane module were conducted. As a result, the useful coefficient and basic data in selecting a membrane module were achieved.

• ETRI Journal
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• v.39 no.6
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• pp.859-865
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• 2017

This paper presents a method for determining the optimum active-area width (OAW) of solar cells in a module architecture. The current density-voltage curve of a reference cell with a narrow active-area width is used to reproduce the current density profile in the test cell whose active area width is to be optimized. We obtained self-consistent current density and electric potential profiles from iterative calculations of both properties, considering the distributed resistance of the contact layers. Further, we determined the OAW that yields the maximum efficiency by calculating efficiency as a function of the active-area width. The proposed method can be applied to the design of the active area of a dye-sensitized solar cell in Z-type series connection modules for indoor and building-integrated photovoltaic systems. Our calculations predicted that OAW increases as the sheet resistances of the contact layers and the intensity of light decrease.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2015.11a
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• pp.200-201
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• 2015

The unit modular method is one in which unit modules are prefabricated at a factory and then constructed at a construction site. That is why an important process, transporting unit module, is added in this method. The purpose of this study is to analyse the load for transporting unit module. The results of the analysis of the driving experimental runs revealed that a maximum load of 15 kN was applied on adapter block type A and a maximum load of 25 kN on adapter block type B. These loads were recorded at the points in the road test when the low-bed trailer was driving through unstable sections of the test such as stopping, restarting, passing over a speed bump or taking a left turn at speed.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1994.10a
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• pp.64-73
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• 1994

An updated Lagrangian finite element analysis with automatic remeshing scheme is applied to the three-dimensional hot extrusion through landless square dies. In the remeshing procedure, it is very difficult that the meshes are generated automatically with consideration of physical characteristics. In the presented study, the mesh generation is accomplished by modular concept. The generated meshes by modular concept have advantages, especially for three-dimensional problems, such as economized computational time and consideration of physical characteristic. In the problem, orifice shapes of square die are divided into two for the extrusion of solid sections. The orifice adaptive modules are developed for each type and the numerical examples are carried out for each type.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.45 no.1
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• pp.100-112
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• 1996

This paper presents a design experience of a control language for coordination of a multi-robot system. To effectively program job commands, a Petrinet-type Graphical Robot Language(PGRL) is proposed, where some functions, such as concurrency and synchronization, for coordination among tasks can be easily programmed.In our system, the proposed task commands of PGRL are implemented by employing formal model languages, which are composed of three modules, sensory, data handling, and action module. It is expected that by using our proposed PGRL and formal languages, one can easily describe a job or task, and hence can effectively operate a complex real-time and concurrent system. The control system is being implemented by using VME-based 32-bit microprocessor boards for supervisory, each module controller(arm, hand, leg, sensor data processing module) and a real time multi-tasking operating system(VxWorks). (author). 17 refs., 16 figs., 2 tabs.

• Korean Journal of Remote Sensing
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• v.9 no.1
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• pp.51-78
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• 1993

The main purpose of this paper is to design and implement an integrated geigraphic information system. To this end, careful examinations of various existing GIS packages based on vector and raster type model were performed. A vector type INTGIS which is operating in MS-Windows environment was developed. INTGIS is composed of many modules creating various menus which are able to facilitate user interface with the system. The function and utility of INTGIS was tested using real data. We found INTGIS is reliable and useful for extensive spatial analysis and mapping activity. Further development of INTGIS will be carried on in order to integrate vector and raster data, and to manipulate three dimensional data.

• Korean Journal of Remote Sensing
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• v.24 no.5
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• pp.417-425
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• 2008

An image-based atmospheric correction software ATC is implemented using MATLAB and SML (Spatial Modeler Language in ERDAS IMAGINE), and it was tested using Landsat TM/ETM+ data. This ATC has two main functional modules, which are composed of a semiautomatic type and an automatic type. The semi-automatic functional module includes the Julian day (JD), Earth-Sun distance (ESD), solar zenith angle (SZA) and path radiance (PR), which are programmed as individual small functions. For the automatic functional module, these parameters are computed by using the header file of Landsat TM/ETM+. Three atmospheric correction algorithms are included: The apparent reflectance model (AR), one-percent dark object subtraction technique (DOS), and cosine approximation model (COST). The ACT is efficient as well as easy to use in a system with MATLAB and SML.