• Electrical & Electronic Materials
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• v.8 no.6
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• pp.708-714
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• 1995

We have discussed the buried-channel(BC) behavior through the subthreshold characteristics of submicron PMOSFET device fabricated with twin well CMOS process. In this paper, we have guessed the initial conditions of ion implantation using process simulation, obtained the subthreshold characteristics as a function of process parameter variation such as threshold adjusting ion implant dose($D_c$), channel length(L), gate oxide thickness($T_ox$) and junction depth of source/drain($X_j$) using device simulation. The buried channel behavior with these process prarameter variation were showed apparent difference. Also, the fabricated pMOSFET device having different channel length represented good S.S value and low leakage current with increasing drain voltage.

• Proceedings of the Korea Society for Simulation Conference
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• 1997.04a
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• pp.103-103
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• 1997

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.987-992
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• 2005

Manufacturing companies should perform process planning and its evaluation concurrently with new product developments so that they can be highly competitive in the modern market. Process planners should make decisions in the manner of concurrent and collaborative engineering in order to reduce the manufacturing preparation time and cost when developing new products. Automated generation of analysis models from the integrated database, which contains process and material information, reduces time to prepare analyses and makes the models reliable. In this research, we developed a web-based system for concurrent and collaborative system for production flow analysis, using web, database, and simulation technology. An integrated database is designed to automatically generate analysis models from process and material plans without reworking the data. This system enables process planners to evaluate their decision fast and share their opinions with others easily. With this system, it is possible to save time and cost for assembly process and material planning, and reliability of process plans can be improved

• Korean Journal of Construction Engineering and Management
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• v.8 no.1 s.35
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• pp.87-95
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• 2007

If construction process operate composing work team by judgment manager's experience, possibility that progress of construction process becomes as inefficient is much. But, If produce optimal proposal of resources allocation, construction cost and duration through simulation at work plan step, work schedule because do quantification efficient operate do on. When plan construction process in this research, resources allocation by change of work team operation change, resources cost loss, total cost, optimal proposal of construction duration tentative plan of numerical formula model that can do simulation propose. Apply and revealed to apartment house framework which horizontal work area of process and vertical work area are composed as is each different construction process to verify proposed numerical formula model. Achieved efficiency than work team's operation results which apply numerical formula model that is presented in this research and enforce simulation is applied in actuality example construction.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.1
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• pp.152-157
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• 2003

Process design of hot forging, asymmetric to symmetric rib-web shape steel, which is used for the turnout of railway express has been investigated. Owing to the big difference in shape between the initial billet and the final forged product, it is impossible to hot forge the rail in a single step. Therefore, multi step forging as well as die design for each step are necessary for the production. The deformation behavior during hot forging has been analyzed by the numerical simulation through commercial FEA software, $DEFORM^{TM}$-2D. Modification of the design and repeated simulation have been carried out on the basis of the simulation result. For comparison with the simulation results. flow analysis experiment using plasticine has been also carried out. The results of the flow analysis experiment showed good agreement with those of the simulation. Therefore, the developed process design could be applied to the actual production.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.19 no.7
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• pp.60-66
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• 2020

In order to improve fatigue life of transmission gear carburizing is normally used. Carburizing is a very good process to achieve low cost and high performance. The machined gears are heated up to carburizing temperature and then cooled rapidly in an oil bath to produce high surface hardness. The gears may undergo excessive thermal distortion during heating and rapid cooling. In order to predict the distortion during heating and rapid cooling, a coupled thermo-mechanical simulation is needed. In the current research, the simulation of heating and cooling was performed. The results show that the thermal distortion and the residual stresses are well predicted by the coupled simulation. In addition, induction heating and rapid cooling simulation is carried out to predict the thermal distortion. The amount of distortion is compared. It is shown that induction heating is very effective to reduce thermal distortion.

• Journal of Intelligence and Information Systems
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• v.18 no.2
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• pp.157-175
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• 2012

It is difficult to evaluate the performance of process innovation of e-procurement which has large scale and complex processes. The existing evaluation methods for measuring the effects of process innovation have been mainly done with statistically quantitative methods by analyzing operational data or with qualitative methods by conducting surveys and interviews. However, these methods have some limitations to evaluate the effects because the performance evaluation of e-procurement process innovation should consider the interactions among participants who are active either directly or indirectly through the processes. This study considers the e-procurement process as a complex system and develops a simulation model based on MAS(Multi-Agent System) to evaluate the effects of e-procurement process innovation. Multi-agent based simulation allows observing interaction patterns of objects in virtual world through relationship among objects and their behavioral mechanism. Agent-based simulation is suitable especially for complex business problems. In this study, we used Netlogo Version 4.1.3 as a MAS simulation tool which was developed in Northwestern University. To do this, we developed a interaction model of agents in MAS environment. We defined process agents and task agents, and assigned their behavioral characteristics. The developed simulation model was applied to G2B system (KONEPS: Korea ON-line E-Procurement System) of Public Procurement Service (PPS) in Korea and used to evaluate the innovation effects of the G2B system. KONEPS is a successfully established e-procurement system started in the year 2002. KONEPS is a representative e-Procurement system which integrates characteristics of e-commerce into government for business procurement activities. KONEPS deserves the international recognition considering the annual transaction volume of 56 billion dollars, daily exchanges of electronic documents, users consisted of 121,000 suppliers and 37,000 public organizations, and the 4.5 billion dollars of cost saving. For the simulation, we analyzed the e-procurement of process of KONEPS into eight sub processes such as 'process 1: search products and acquisition of proposal', 'process 2 : review the methods of contracts and item features', 'process 3 : a notice of bid', 'process 4 : registration and confirmation of qualification', 'process 5 : bidding', 'process 6 : a screening test', 'process 7 : contracts', and 'process 8 : invoice and payment'. For the parameter settings of the agents behavior, we collected some data from the transactional database of PPS and some information by conducting a survey. The used data for the simulation are 'participants (government organizations, local government organizations and public institutions)', 'the number of bidding per year', 'the number of total contracts', 'the number of shopping mall transactions', 'the rate of contracts between bidding and shopping mall', 'the successful bidding ratio', and the estimated time for each process. The comparison was done for the difference of time consumption between 'before the innovation (As-was)' and 'after the innovation (As-is).' The results showed that there were productivity improvements in every eight sub processes. The decrease ratio of 'average number of task processing' was 92.7% and the decrease ratio of 'average time of task processing' was 95.4% in entire processes when we use G2B system comparing to the conventional method. Also, this study found that the process innovation effect will be enhanced if the task process related to the 'contract' can be improved. This study shows the usability and possibility of using MAS in process innovation evaluation and its modeling.

• Journal of Korean Society of Water and Wastewater
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• v.16 no.6
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• pp.670-678
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• 2002

Since Korean government imposed a stricter regulation on effluent T-N and T-P concentrations from wastewater treatment plant, a new process has to be developed to meet these rules and this process should remove T-N and T-P, economically, from weak wastewater that is typical for Korea's combined sewer system sewage. In this study, a computer simulator, BioWin from EnviroSim, Inc. was used. Three processes - A2/O, Modified Johannesburg, UCT- had been simulated under same operational conditions and a new process - Parallel BNR Process - had been developed based on these simulation results. The Parallel BNR process consists of two rows of reactors: One row has anaerobic and aerobic reactors in series, and the other row has RAS anoxic1 and RAS anoxic2 reactors in series. In order to ensure anaerobic state in anaerobic tank, a part of influent is fed to RAS anoxic1 tank in second row. This process had been simulated under same conditions of other three processes and the simulation results were compared. The results showed that three existing processes could not perform biological phosphorus removal when the average influent was fed at any operation temperatures. However, the Parallel BNR process was found that biological phosphorus removal could be performed when both design and average influent were fed at any operation temperatures. This process showed the T-N concentration in effluent had a maximum value of 15mg/L when design influent was fed at $13^{\circ}C$ and a minimum value of 14mg/L when average influent was fed at $20^{\circ}C$. Also, T-P concentrations had a maximum value of 1.3mg/L when average influent was fed at $20^{\circ}C$ and a minimum value of 1.1mg/L when design influent was fed at $13^{\circ}C$. Based on these results, we found that this process can remove nitrogen and phosphorus biologically under any operational conditions.

• Journal of the Korea Society for Simulation
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• v.23 no.4
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• pp.203-210
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• 2014

This study proposes adaptive decision making method having feed-back structure of regression and simulation models to support the quick decision making of production managers by managing and integrating the mutual relationship among historical data. For that, from historical data that have extracted and accumulated from each process, we first selected major constraint resources that are used as independent variables in regression model. The regression model is designed by using the dependent variables (objectives) that defined above by managers and independent variables selected in previous step and simulation model that are composed of constraint resources is designed. In process of simulation run, we obtain the multiple feasible solutions (alternatives) by using meta-heuristic method. Each solution is substituted by regression equation and we found the optimal solution that is minimum of difference between values obtained by regression model and simulation results. The optimal solution is delivered and incorporated to production site and current operation results from production site is used to generate new regression model after that time.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.7 no.3
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• pp.75-80
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• 2008

The progressive die performs a work of sheet metal processes with a piercing, notching, embossing, bending, drawing, cut-off etc. in many kinds of pressing. Now a days, these processes have been evaluated as a advanced tooling method to increase the productivity and high quality assurance. The first step analyzing of die design is production part review, then the arrangement drawing of product design and strip process layout design should be done as a next steps with a FEM simulation for its problem solution. After upper procedure were peformed, it was started to make the die, then tryout and its revision of the die and product quality, safety, productivity etc. were done continually. For the all of these process, we mobilized the theory and practice of sheet metal forming, die structure, the function and activity of die components, and the others of die machining, die material, heat treatment and know‐how so on. In this study the features of representative are production part analyzing through the FEM simulation of bending area with a considering spring back problem by DEFORM.