• Proceedings of the Korea Society for Simulation Conference
• /
• 2003.11a
• /
• pp.27-34
• /
• 2003

A distributed server cluster system is a cost-effective system to provide a service application for clients with reliable, scalable, available, and fault-tolerant features. In order to provide high quality services, it is necessary to evaluate service performances, tune the server system, and analyze performances. In this paper, we propose a simulator to generate workloads based on statistic configuration according to estimated application traffics, apply workload scheduling algorithms, and evaluate the simulation results. We introduce the simulator design modelling and architecture. By using flexible parameters, the simulator is able to generate various patterns of workloads with different statistics, and configure system environments such as the number of server nodes, system resources considered, and their capacities. With this simulator, we introduce two scenarios: one is to find appropriate thresholds for the best performance of cluster system, and the other is to find the suitable scheduling algorithm for workload characteristics of service applications.

• Journal of Advanced Marine Engineering and Technology
• /
• v.30 no.6
• /
• pp.662-668
• /
• 2006

The effects of fuel injection nozzle hole on the NOx emission and fuel oil consumption of medium speed diesel engine HYUNDAI HiMSEN 6H21/32 engine are investigated by engine performance simulation. The results of performance simulation are verified by experimental results of NOx omission fuel oil consumption, cylinder pressure, and heat release rate according to the variation of the number of fuel injection nozzle hole and engine load. The performance simulations are also carried out to optimize the fuel injection nozzle of 6H21/32 engine in respect to the NOx emission and fuel oil consumption. The engine performance measurements are performed to verify the results of performance simulation and to investigate the effects of fuel injection nozzle on engine performance. The results of measurement indicate that significant NOx reduction can be achieved with minimum deterioration in fuel oil consumption by optimizing the geometry of fuel injection nozzle on 6H21/32 engine.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.24 no.1 s.173
• /
• pp.134-143
• /
• 2000

A train performance simulation (TPS) software is a computer program that simulates the operation of a train system over a specified railway route and it is widely used in railroad operation and research applications. Numerical and graphical results from the simulation software, which is developed in this study, provide information on such performance variables as travel time. running speed, energy consumption at a specific time interval and in overall service time as the train moves along the route. Three types of input data are required for a computer simulation: track information, train information, and running conditions. The simulation of train performance starts with several simple mathematical models including train configuration. traction efforts, running resistance. and braking requirements. Based on the basic specifications of Korean High Speed Railway, System. this study, puts a focus on the estimation and assessment of train performance comparing. the specific train configurations of KEST20/11. CPLE20/10. PROP20/10, which are proposed from the previous G7 projects.

• Journal of the Korea Society for Simulation
• /
• v.12 no.3
• /
• pp.69-81
• /
• 2003

To manage a cluster of distributed server systems, a number of management aspects should be considered in terms of configuration management, fault management, performance management, and user management. System performance monitoring and reporting take an important role for performance and fault management. In this paper, we present distributed system architecture modeling of a performance monitoring and reporting tool. Modeling architecture of four subsystems are introduced: node agent, data collection, performance management & report, and DB schema. The performance-related information collected from distributed servers are categorized into performance counters, event data for system status changes, service quality, and system configuration data. In order to analyze those performance information, we use a number of ways to evaluate data corelation. By using some results from a real site of a company and from simulation of artificial workload, we show the example of performance collection and analysis. Since our report tool detects system fault or node component failure and analyzes performances through resource usage and service quality, we are able to provide information for server load balancing, in short term view, and the cause of system faults and decision for system scale-out and scale-up, in long term view.

• Journal of the Korea Society for Simulation
• /
• v.3 no.1
• /
• pp.55-63
• /
• 1994

FMS is two or more computer controlled units interconnected with automated workhandling equipment and supervised by an executive computer having random scheduling capabilities. The complex nature of a FMS, coupled with the need to maximize its performance, means that such a system can be effectly designed only by iterative computer simulation methods. At the operational level, simulation had a reduced role to evaluate the performance of planned FMS under a variety of operating strategies. This is probably due to the fact that few simulation models are able to access the current status data of the system. This study reviews the role of simulation for design/operation of FMS and suggests an interface scheme for incorporating a simulation package with a FMS operational database. This scheme can be used for reducing the performance gap between design and real operation of a FMS.

• The Journal of Korean Academic Society of Nursing Education
• /
• v.18 no.1
• /
• pp.111-119
• /
• 2012

Purpose: The purpose of this study was to identify the effects on knowledge and performance confidence of nursing students in the emergency care of patients with dyspnea after simulation education using a human simulator. Method: The research design was a nonequivalent control group pretest-posttest design. For the experimental group the human simulator was used to provide simulation. Also included were base learning with audio-visual material, explanations about simulation, using SimMan for human simulation, and debriefing. Pre and post-tests were conducted to compare differences in knowledge and performance confidence. Result: The (t=3.83, p<.000) than the control group. For the experimental group, the differences in pretest-posttest scores for knowledge (t=2.30, p=.025) and performance confidence (t=4.28, p<.000) were significantly higher than the experimental group had significantly higher scores for knowledge (t=3.03, p=.004) and performance confidence (t=3.83, p<.001knowledge (t=2.30, p=.025) and performance confidence (t=4.28, p<.000) were significantly higher than the control group. Conclusion: The results of this study indicate that for student nurses, knowledge and performance confidence in emergency care of patients with dyspnea improve with human simulator simulation education. Further study is suggested to develop other scenarios for emergency care and identify the effects of critical thinking and satisfaction when using human simulator simulation education.

• Proceedings of the Korea Society for Simulation Conference
• /
• 1992.09a
• /
• pp.161-167
• /
• 1992

The spcaker will briefly summarized the current state of the art in commericial simulation tools as limited by soft ware and hardware technology. He will then discuss how recent and near-future advances in software and hardware tenilogy can be applied to the benefit of simulationists. Specifically, the following topics will be ciscussed : Simulation Languages vs Simulations ; Computer hardware platforms ; Performance liminting factors ; Performance assisting techniques ; Software architectures ; Human factors and model interaction.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.20 no.3
• /
• pp.155-166
• /
• 2008

The performance evaluation of a new building is becoming more important because efficient design alone is often not sufficient to deliver an efficient building. However, there is a lack of standard evaluation methods to measure the energy performance of a new construction that has Energy Conservation Design Measures(ECDMs). This study presents an enhanced method based on calibrated whole-building simulation for evaluating the energy performance of new commercial buildings and demonstrates its use using a case-study building, including: an Energy Use Index(EUI) comparison with sub-metered data and an evaluation of the performance of specific ECDMs. The use of this method has determined that the case-study building was shown to use approximately 47% less energy than the base-case building that has the same shape and function as the case-study building(i.e., calibrated as-built simulation mode]), but doesn't include the simulated ECDMs.

• Journal of the Korean Solar Energy Society
• /
• v.31 no.6
• /
• pp.103-110
• /
• 2011

The aim of this study was to analysis the Heating/cooling performance and Daylighting performance of Solar Window System built in apartments. the solar window is the idea to integrate daylight as a third form of solar energy into a PV/Solar Collector system. The process of this study is as follows: 1)Solar Window system was designed through the investigation of previous paper and work. 2)The simulation program(Lightscape3.2) was used in daylighting performance analysis. the reference model of simulation was made up to analysis daylighting performance on Solar Window system. 3)The simulation program(ESP-r, Therm5.0, Window6.0) was used in energy performance analysis. the reference model of simulation was made up to analysis energy and daylighting performance on Solar Window system. 4)The Size of Simulation model for daylighting and heating/cooling energy analysis was $148.5m^2$ 5)The lighting performance analysis was carried out with various variants, such as the size and installed area of Solar Window system. 6)Energy performance simulation was carried out with various variants, such as Integrated U-value of Solar Window system according to its position, installed angle and insulation thickness. Consequently, When Solar Window system is equipped with balcony window of Apartment, Annual heating and cooling energy of reference model was cut down at the average of $4.1kWh/m^2$ or 4.2%.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2004.03a
• /
• pp.513-520
• /
• 2004

A steady-state/transient performance simulation model was newly developed for the propulsion system of the CRW (Canard Rotor Wing) type UAV (Unmanned Aerial Vehicle) during flight mode transition. The CRW type UAV has a new concept RPV (Remotely Piloted Vehicle) which can fly at two flight modes such as the take-off/landing and low speed forward flight mode using the rotary wing driven by engine bypass exhaust gas and the high speed forward flight mode using the stopped wing and main engine thrust. The propulsion system of the CRW type UAV consists of the main engine system and the duct system. The flight vehicle may generally select a proper type and specific engine with acceptable thrust level to meet the flight mission in the propulsion system design phase. In this study, a turbojet engine with one spool was selected by decision of the vehicle system designer, and the duct system is composed of main duct, rotor duct, master valve, rotor tip-jet nozzles, and variable area main nozzle. In order to establish the safe flight mode transition region of the propulsion system, steady-state and transient performance simulation should be needed. Using this simulation model, the optimal fuel flow schedules were obtained to keep the proper surge margin and the turbine inlet temperature limitation through steady-state and transient performance estimation. Furthermore, these analysis results will be used to the control optimization of the propulsion system, later. In the transient performance model, ICV (Inter-Component Volume) model was used. The performance analysis using the developed models was performed at various flight conditions and fuel flow schedules, and these results could set the safe flight mode transition region to satisfy the turbine inlet temperature overshoot limitation as well as the compressor surge margin. Because the engine performance simulation results without the duct system were well agreed with the engine manufacturer's data and the analysis results using a commercial program, it was confirmed that the validity of the proposed performance model was verified. However, the propulsion system performance model including the duct system will be compared with experimental measuring data, later.