• Journal of the Korea Society of Computer and Information
• /
• v.11 no.6 s.44
• /
• pp.113-123
• /
• 2006

Flash memory has been increasingly used in handhold devices not only for data storage, but also for code storage. Because NAND flash memory only provides sequential access feature, a traditionally accepted solution to execute the program from NAND flash memory is shadowing. But, shadowing has significant drawbacks increasing a booting time of the system and consuming severe DRAM space. Demand paging has obtained significant attention for program execution from NAND flash memory. But. one of the issues is that there has been no effort to bound demand paging cost in flash memory and to analyze the worst case performance of demand paging. For the worst case timing analysis of programs running from NAND flash memory. the worst case demand paging costs should be estimated. In this paper, we propose two different WCRT analysis methods considering demand paging costs, DP-Pessimistic and DP-Accurate, depending on the accuracy and the complexity of analysis. Also, we compare the accuracy butween DP-Pessimistic and DP-Accurate by using the simulation.

• Journal of the Korea Society of Computer and Information
• /
• v.13 no.4
• /
• pp.213-220
• /
• 2008

The purpose of this paper is to improve efficiency in the construction and operation of a total management system for the national technical qualification through the design and development of a real-time data sharing system which is connected with the management system of external consignment. The current a total management system for the national technical qualification precesses the work depend on information and results which pass over by external IT company. But this method of processing has some unstable elements with regards to information reprocessing, functional supplement, system stability, etc. The proposed system's technological concepts have been tested through a basic simulation pilot program. The pilot program will be expanded to include the local Chamber of Commerce and Industry because the stability of the system was proved through its application to the real-time national technical qualification examination of KCCI(Korea Chamber of Commerce and Industry). The real-time data sharing system has shown great efficiency in terms of system management, and has solved problems of developmental period for information reprocessing and functional supplement. The real-time data sharing system has been given good evaluations with regard to the convenience of their use and the management system for operators and supervisors.

• Journal of Korea Foundry Society
• /
• v.17 no.5
• /
• pp.465-471
• /
• 1997

An integrated computer program consisting of a pre-processor, main solver, and post-processor was developed for the design of large steel castings. The pre-processor, based on the AutoCAD, enables the user to produce approval drawings, casting design drawings and mesh diagrams in sequence using a personal computer. In the main solver, two numerical models were employed; one models the fluid flow during mold filling, and the other models the heat transfer and solidification. The post-processor can be used to present simulation results such as flow pattern, mold filling sequences, solidification times, temperature gradients and location of shrinkage defects by color graphics. In order to validate the applicability of the present integrated program, a series of experiments on simple-shaped steel castings were carried out. After the validation of the present model, it was applied to the casting design of the large steel anchor of an SC42 alloy. Various solidification parameters such as a temperature distribution and a solidification time in the casting and the mold were compared with those obtained experimentally. Simulated results predicting shrinkage defects were in good agreement with those obtained experimentally. It was found that the present method can be successfully applied to the quantitative casting design for complex-shaped large steel castings.

• Communications of the Korean Institute of Information Scientists and Engineers
• /
• v.1 no.1
• /
• pp.23-35
• /
• 1983

In its global meaning language translation refers to the process whereby a program which is executable in one computer can be executed in another computer directly to obtain the same result. There are four different ways of approaching translation. The first way is translation by a Translator or a Compier, the second way is Interpretation, the third way is Simulation, the last way is Emulation. This paper introduces the M-C Translator which was designed as the first way of translation. The MUSS 80 language (the subsystem of the UNIVAC Solid State 80 S-4 assembly language system) was chosen as the source language which includes forty-three instructions, using the CYBER COMPASS as the object language. The M-C translator is a two pass translator and is a two pas translator and es written in Fortran Extended language. For this M-C Translation, seven COMPASS subroutines and a set of thirty-five macros were prepared. Each executable source instruction corresponds to a macro, so it will be a macro instruction within the object profram. Subroutines are used to retain and handle the source data representation the same way in the object program as in the source system, and are used to convert the decimal source data into the equivalent binary result into the equivalent USS-80digits before and after arithmetic operations. The source instructions can be classified into three categories. First, therd are some instructions which are meaningless in the object system and are therefore unnecessary to translate, and the remaining instructions should be translated. Second, There are some instructions are required to indicate dual address portions. Third, there are Three instructions which have overflow conditions, which are lacking in the remaining instructions. The construction and functions of the M-C Translator, are explained including some of the subroutines, and macros. The problems, difficulties and the method of solving them, and easier features on this translation are analysed. The study of how to save memory and time will be continued.

• Journal of the Korea Organic Resources Recycling Association
• /
• v.31 no.2
• /
• pp.19-38
• /
• 2023

Nitrous oxide, one of the six greenhouse gases from Kyoto protocol, is known to be emitted in biological nitrification and denitrification reactions at wastewater treatment plant. In this study, EQPS which is a computer program that can simulate nitrous oxide gas emission amount at wastewater treatment plants is used. The MLE process which treats wastewater from combined sewer is studied. Operational variables which are MLR, water temperature at reactor and primary clarifier by-pass percentage are changed to define the condition which produces the least amount of nitrous oxide gas. 200 % of MLR, 20 ℃ of water temperature at bioreactor and 15 % of primary clarifier by-pass percentage are shown the least nitrous oxide emission factor. Also, it is found that the deep aeration tank produces less amount of nitrous oxide gas since less air is required to meet oxygen demand in this type of aeration tank.

• Journal of the Korea Society for Simulation
• /
• v.25 no.4
• /
• pp.53-63
• /
• 2016

This study aims to verify the feasibility of design by developing pressure flow-controlled swash plate type pump with the use of SimulationX, a computer analysis program. Developing analysis model based on design drawing data has a cost-saving effect because it is possible to figure out the effectiveness of design through the work and it never falls into repeated inaccuracies in the production process. Analysis model is developed in the following order. First, the structure of each part such as valve and rotating unit which have dynamic factor is analyzed and the modeling of single component is carried out, reflecting drawing data. Second, the modeling of pump assembly is carried out with the combination of each analysis model and a work is conducted to determine whether the modeling can perform pressure flow control function according to load condition smoothly based on design intent. At the end of the modeling process, the feasibility of design is verified by showing the parts which are moving as expected mechanism.

• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.26 no.1
• /
• pp.137-143
• /
• 2017

An axial fan has competitive advantages that can make air flow more straight and longer and produce larger air volume than the other kinds of fans. In those reasons, axial fans are widely used for ventilator, 4D cinema, duct, and so on. But, as it was designed and manufactured without any mathematical analysis or computer simulations, it is difficult to develop the performance of axial fans. Actually the axial fan is designed and manufactured in industry by imitation or traditional method. Flow velocity and volume of axial fan are changed by pitch angle, frame, the number of blade, camber angle, and chord length. In this paper, the performance of axial fan was analyzed and by computer program known as CFD. Finally, we have designed a new axial fan whose velocity and volume is improved. The performance of new axial fan is also compared with the of conventional fans experimentally.

• Journal of Electrical Engineering and Technology
• /
• v.13 no.6
• /
• pp.2220-2226
• /
• 2018

Electric vehicles (EVs) are significant resources for demand response (DR). Thus, it is essential for EV aggregators to quantitatively evaluate their capability for DR. In this paper, a concept of dynamic equivalent battery (DEB) is proposed as a metric for evaluating the DR performance using EVs. The DEB is the available virtual battery for DR. The capacity of DEB is determined from stochastic calculation while satisfying the charging requirements of each EV, and it varies also with time. Further, a new indicator based on the DEB and time-varying electricity prices, named as value of DEB (VoDEB), is introduced to quantify the value of DEB coupled with the electricity prices. The effectiveness of the DEB and the VoDEB as metrics for the DR performance of EVs is verified with the simulations, where the difference of charging cost reduction between direct charging and optimized bidding methods is used to express the DR performance. The simulation results show that the proposed metrics accord well with the DR performance of an EV fleet. Thus, an EV aggregator may utilize the proposed concepts of DEB and VoDEB for designing an incentive scheme to EV users, who participate in a DR program.

• Computers and Concrete
• /
• v.14 no.2
• /
• pp.193-209
• /
• 2014

Cyclic test of the columns is of practical relevance to the performance of compression members during an earthquake loading. The strength, ductility and energy absorption capabilities of reinforced concrete (RC) columns subjected to cyclic loading have been estimated by many researchers. These characteristics are not normally inherent in plain concrete but can be achieved by effectively confining columns through transverse reinforcement. An extensive experimental program, in which performance of four RC columns detailed according to provisions of ACI-318-08 was studied in contrast with that of four columns confined by a new proposed technique. This paper presents performance of columns reinforced by standard detailing and cast with 25 and 32 MPa concrete. The experimentally achieved load-displacement hysteresis and backbone curves of two columns are presented. The two approaches which work in conjunction with Response 2000 have been suggested to draw analytical back bone curves of RC columns. The experimental and analytical backbone curves are found in good agreement. This investigation gives a detail insight of the response of RC columns subjected to cyclic loads during their service life. The suggested analytical procedures will be available to the engineers involved in design to appraise the capacity of RC columns.

• Journal of the Korean Institute of Telematics and Electronics S
• /
• v.36S no.6
• /
• pp.45-56
• /
• 1999

This paper presents a method for designing an autopilot of the BTT missile using 2DOF Wiener-Hopf control technique to improve tracking performance. Linear controllers are designed based on the linearized models which are obtained from the nonlinear missile dynamic equations at various operating points. The gain scheduling technique is used to implement the final autopilot. A simulation on the flight of missiles is carried out through the use of 6DOF equation program including exact nonlinear equations of the missile and the variations of aerodynamic variables in order to check applicability of the suggested method in real situation.