• Journal of Energy Engineering
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• v.2 no.1
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• pp.28-37
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• 1993

This paper describes the development of a dynamic model of 1,000 MW$\_$e/ nuclear power plant including its local and integrated control system. The model was constructed using the Modular Modeling System (MMS) developed by the Electric Power Research Institute (EPRI) to provide an efficient, economical and user-friendly computer code for use in the analysis of the dynamic performance of nuclear and fossil power plants in conjunction with the Advanced Continuous Simulation Language (ACSL). Steady state for full load and transient results for turbine power step changes of loft are presented in this paper. The model includes most major components of a 1,000 MW$\_$e/ nuclear power plant and it can readily be modified to simulate a specific power plant. This procedure greatly reduces the analysis and modeling efforts involved in dynamic simulation of power plants and increases confidence in the analysis results.

• Journal of KIISE:Information Networking
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• v.30 no.3
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• pp.397-406
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• 2003

As the information technology grows interests in the intrusion detection system (IDS), which detects unauthorized usage, misuse by a local user and modification of important data, has been raised. In the field of anomaly-based IDS several artificial intelligence techniques such as hidden Markov model (HMM), artificial neural network, statistical techniques and expert systems are used to model network rackets, system call audit data, etc. However, there are undetectable intrusion types for each measure and modeling method because each intrusion type makes anomalies at individual measure. To overcome this drawback of single-measure anomaly detector, this paper proposes a multiple-measure intrusion detection method. We measure normal behavior by systems calls, resource usage and file access events and build up profiles for normal behavior with hidden Markov model, statistical method and rule-base method, which are integrated with a rule-based approach. Experimental results with real data clearly demonstrate the effectiveness of the proposed method that has significantly low false-positive error rate against various types of intrusion.

• Journal of Internet Computing and Services
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• v.10 no.6
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• pp.7-17
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• 2009

The development of wireless communication MAC layer is usually released as SoC which is a combination in hardware and software. In this system development environment, an environment for software development and verification is necessary because the hardware development takes a lot of time priori to completion. In integrated development of hardware and software, simulation environment of hardware and software provided by hardware modeling using HDL at RTL and ISS respectively. By increasing the development complexity of system, ESL design modeling systems at higher abstraction level than RTL has already prompted. The ESL design is divided untime model and time model. This paper present design and implementation of MCU for untime model simulation, not time model. Proposed MCU can optimize the system at early step of system development and move up the development completion time by verifying the system function easily and rapidly than part required exact time in untime model. In this paper, we present an MCU module based on SystemC and UC/OS-II Module providing real-time operate system.

• Journal of Mechanical Science and Technology
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• v.20 no.1
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• pp.85-93
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• 2006

The trend of miniaturization has been applied to the research of rockets to develop prototypes of micro rockets. In this paper, the development of a web-integrated prototyping system for three-dimensional micro rockets, and the results of combustion tests are discussed. The body of rocket was made of 6061 aluminum cylinder by lathe process. The three-dimensional micro nozzles were fabricated on the same aluminum by using micro endmills with ${\phi}100{\mu}m{sim}{\phi}500{\mu}m$ diameter. Two types of micro nozzle were fabricated and compared for performance. The total mass of the rockets was 7.32 g and that of propellant (gun powder) was 0.65 g. The thrust-to-weight ratio was between 1.58 and 1.74, and the flight test with 45 degree launch angle from the ground resulted in $46\;m{\sim}53\;m$ of horizontal flight distance. In addition, ABS housing for the micro machined rocket was fabricated using Fused Deposition Modeling (FDM). A web-based design, fabrication, and test system for micro nozzles was proposed to integrate the distributed hardware resources. Test data was sent to the designer via the same web server for the faster feedback to the rocket designer.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2009.04a
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• pp.344-347
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• 2009

건축, 토목 분야의 정보 교환을 위한 표준으로 주목받고 있는 BIM 모델의 국제 표준인 IFC 표준을 위해, 소프트웨어가 IFC 표준에 맞게 유효한 정보를 입출력 하도록 도와주고, IFC 파일이 표준에 맞는지 검증할 수 있는 모듈을 개발했다. 특히, 지역별 및 국가별 상황에 맞게 BIM 모델을 수정하거나 확장해 사용하도록 권고하고 있는 상황에서 다양한 확장 IFC 표준을 효과적으로 지원할 수 있도록 IFC 표준을 정의하는 EXPRESS 언어로부터, 객체 지향 언어를 위한 소프트웨어 개발 라이브러리를 자동으로 생성하고, 해당 SDK를 활용해 IFC 모델을 검증하는 라이브러리를 자동으로 생성하며, IFC 파일을 검증할 수 있는 독립적인 실행 파일도 자동으로 생성할 수 있도록 했다. 또한 객체 지향 라이브러리를 사용함으로써 주어진 IFC 모델을 효과적으로 문서화 할 수 있도록 HTML 생성 도구를 개발하거나 3차원 형상 확인이 가능하도록 VRML 생성 도구를 개발하는 등의 작업이 쉽게 이뤄짐을 확인했다. 이렇게 자동화된 BIM 소프트웨어 개발 도구는 IFC 모델의 수정이나 확장을 고려하는 BIM 소프트웨어 개발 프로젝트의 생산성을 향상시키고, 해당 시스템의 운영에 신뢰도를 높이는 것은 물론이며, 향후 국내 실정에 맞게 운영될 BIM 인증 제도에도 활용하면 기존의 수작업 방식 인증제도에 비해 인증에 걸리는 시간과 비용을 줄이는 것은 물론 인증 자체의 객관성과 정확성, 투명성과 신뢰성을 높일 수 있을 것으로 기대된다.

• Korean Journal of Computational Design and Engineering
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• v.9 no.2
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• pp.167-174
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• 2004

As the networks connect the world, enterprises tend to move manufacturing activities into virtual spaces. Since different applications use different data terminology, it becomes a problem to interoperate, interchange, and manage electronic data among different systems. According to RTI, approximately one billion dollar has been being spent yearly for product data exchange and interoperability. As commercial CAD systems have brought in the concept of design feature for the sake of interoperability, terminologies of design feature need to be harmonized. In order to define design feature terminology for integration, knowledge about feature definitions of different CAD systems should be considered. STEP (Standard for the Exchange of Product model data) have attempted to solve this problem, but it defines only syntactic data representation so that semantic data integration is unattainable. In this paper, we utilize the ontology concept to build a data model of design feature which can be a semantic standard of feature definitions of CAD systems. Using feature ontology, we implement an integrated virtual database and a simple system which searches and edits design features in a semantic way. This paper proposes a methodology for integrating modeling features of CAD systems.

• Ocean Systems Engineering
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• v.5 no.4
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• pp.261-277
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• 2015

Internal solitary waves occur due to density stratification and are nonlinear in nature. These waves have been observed in many parts of the world including the South China Sea, Andaman Sea and Sulu Sea. Their effect on floating systems has been an emerging field of interest and recent offshore developments in the South China Sea where several offshore oil and gas discoveries are located have confirmed adverse effects including large platform motions and riser system damage. A valid numerical model conforming to the physics of internal waves is implemented in this paper and the effect on a spar platform is studied. The physics of internal waves is modeled by the Korteweg-de Vries (KdV) equation, which has a general solution involving Jacobian elliptical functions. The effects of vertical density stratification are captured by solving the Taylor Goldstein equation. Fully coupled time domain analyses are conducted to estimate the effect of internal waves on a typical truss spar, which is configured to South China Sea development requirements and environmental conditions. The hull, moorings and risers are considered as an integrated system and the platform global motions are analyzed. The study could be useful for future guidance and development of offshore systems in the South China Sea and other areas where the internal wave phenomenon is prominent.

• Transactions of the Korean Society of Automotive Engineers
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• v.16 no.4
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• pp.110-119
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• 2008

Computer methods with simplified mathematical models in conjunction with empirical model parameters can be efficiently practiced into an optimization of a diesel aftertreatment system. Components of prime interests are diesel particulate filter, diesel oxidation catalyst and de-$NO_x$ catalytic converter. de-$NO_x$, de-PM, and de-HC processes in each part are individually modeled, formulated and then combined into an integrated analysis procedure for a unified simulation of the diesel emission aftertreatment. The model is empirically tuned and validated with comprehensive engine and laboratory data. The effects of emission species and space velocity on the $NO_x$ and soot reductions are parametrically investigated. A lowered $NO_2/NO_x$ ratio due to PM oxidation in DPF contributes to promote the $NO_x$ reduction by SCR at intermediate gas temperatures. $NO_x$ reduction is inert to the PM oxidation at high temperatures. Rate of PM trapping strongly depends on temperature and $NO_x$ concentration.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.4
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• pp.1972-1986
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• 2017

With the advent of the knowledge economy, science and technology resources have played an important role in economic competition, and their optimal allocation has been regarded as very important across the world. Thus, allocation optimization research for regional science and technology resources is significant for accelerating the reform of regional science and technology systems. Regional science and technology resource allocation optimization is modeled as a double-layer optimization model: the entire system is characterized by top-layer optimization, whereas the subsystems are characterized by bottom-layer optimization. To efficaciously solve this optimization problem, we propose a mixed search method based on the orthogonal genetic algorithm and sensitivity analysis. This novel method adopts the integrated modeling concept with a combination of the knowledge model and heuristic search model, on the basis of the heuristic search model, and simultaneously highlights the effect of the knowledge model. To compare the performance of different methods, five methods and two channels were used to address an application example. Both the optimized results and simulation time of the proposed method outperformed those of the other methods. The application of the proposed method to solve the problem of entire system optimization is feasible, correct, and effective.

• Journal of Institute of Control, Robotics and Systems
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• v.16 no.4
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• pp.319-328
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• 2010

This paper proposes a robust adaptive fuzzy tracking control scheme for a nonholonomic mobile robot with external disturbances as well as parameter uncertainties in the robot kinematics, the robot dynamics, and the actuator dynamics. In modeling a mobile robot, the actuator dynamics is integrated with the robot kinematics and dynamics so that the actuator input voltages are the control inputs. The presented controller is designed based on a FBFN (Fuzzy Basis Function Network) to approximate an unknown nonlinear dynamic function with the uncertainties, and a robust adaptive input to overcome the uncertainties. When the controller is designed, the different parameters for two actuator models in the actuator dynamics are taken into account. The proposed control scheme does not require the kinematic and dynamic parameters of the robot and actuators accurately. It can also alleviate the input chattering and overcome the unknown friction force. The stability of the closed-loop control system including the kinematic control system is guaranteed by using the Lyapunov stability theory and the presented adaptive laws. The validity and robustness of the proposed control scheme are shown through a computer simulation.