• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2012.04a
• /
• pp.439-440
• /
• 2012

New analysis methods complement classical approaches in the vehicle NVH development by reducing and accelerating iteration steps to obtain a target sound. Therefore, tools are required that allow an integrative approach of sound engineering and structural analysis and enable a precise simulation and modification based on measured data. The Response Modification Analysis (RMA) is such a hybrid solution, which provides indications of relevant transfer paths taking into account the sensitivity of response channels to modifications of reference channels.

• Proceedings of the Korea Society for Simulation Conference
• /
• 1993.10a
• /
• pp.11-11
• /
• 1993

도메인에 대한 전문 지식 획득(Acquisition of expert knowlegde)은 지식 제공자인 인간 전문가에 의존한다. 도메인이 복잡해 질수록 인간 전문가로부터 관련된 모든 지식을 획득하기란 어렵다. 이런 지식 획득의 어려움을 부분 흑은 완전 자동화된 지식 획득 시스템을 통해 해결하려는 많은 연구가 있어 왔다. 그러나 지식 획득을 위한 여러 시도들은 지식 제공자의 촛점이 도메인이 아닌 표현 구조나 도구- representation environment -에 보다 치우치게 하여, 잘못된 지식을 획득하게 하거나 주요지식이 생략되는 경우를 보이기도 한다. 또한 정적인 관계(relationship)에 의해서만 지식(Static Knowledge)을 생성하므로 시간흐름에 따라변화하는 지식을 나타내기는 어렵다. 본 연구에서는 시뮬레이션을 통한 자동 지식 획득(Simulation Based automatic Knowledge Acquisition) 방법을 제시한다. 이 방법은 1) 도메인에 관한 초기 인과관계 정보를 입력 받고, 2) 입력된 정보를 일정한 프레임에 따라 구조화 시켜 경험 베이스를 구성하고 이를 탐색하여 도메인과 관련된 확장된 정보를 얻은 후, 3) 위의1),2)를 통해 얻어진 정보를 분석하여 주어지는 입력에 대해 다양한 출력을 낼 수 있는 시뮬레이션 모델을 생성한다. 이 모델은 다음 단계의 지식 생성을 위한 수단(resource)이 되며, 구간값과 같은 불확실한 정보를 포함할 수 있는 구조이다. 마지막으로 4) 생성된 모델을 시뮬레이션하여 결과로 생성된 지식을 획득한다. 위의 과정에서, 지식획득을 위한 수단인 시뮬레이션 모델이 지식 제공자의 개입 없이 자동 생성됨에 따라, 지식 제공자는 도메인 관련 지식 그 자체에 집중할 수 있으며, 생성된 모델을 시뮬레이션한 결과에 의해 지식을 생성함으로써 동적인 지식이 얻어질 수 있다. DEVS 모델에 대한 타당성 검사 방법을 고찰하고 그 문제점에 대하여 자세히 설명한다. DEVS 모델의 타당성 검사에 이용하는 SPN 모델에 대한 개념과 DEVS 모델과 행위적으로 동등한 SNP 모델로 변환을 위한 관점을 제조명하다. 동일한 관점에서 두 모델의 상태표현이 같도록 DEVS 모델이 SPN 모델로 표현됨을 보이는 변환이론을 제시하고 변환이론을 바탕으로 모델 변환과정을 제시한다. 모델 변환이론과 변환고정을 기본으로 타당성 검사를 위한 새로운 동질함수(homogeneous function)를 정의하고 이와 함께 SPN 모델의 특성을 이용하여 DEVS 모델에 대한 타당성 검사 방법을 새롭게 제안한다. 에탄올투여로 증가된 유리기 해독계 효소인 GSH-Px활성을 큰 폭으로 감소시키고 에탄올투여로 감소된 비효소적 항산화작용을 나타내는 GSH함량을 다량 증가시킴으로서 지질과산화물에 대한 방어력이 증가되어 나타난 결과로 여겨지며, 또한 혈청중의 ALT, ALP 및 LDH활성을 유의성있게 감소시키므로서 감잎 phenolic compounds가 에탄올에 의한 간세포 손상에 대한 해독 및 보호작용이 있는 것으로 사료된다.반적으로 홍삼 제조시 내공의 발생은 제조공정에서 나타나는 경우가 많으며, 내백의 경우는 홍삼으로 가공되면서 발생하는 경우가 있고, 인삼이 성장될 때 부분적인 영양상태의 불충분이나 기후 등에 따른 영향을 받을 수 있기 때문에 앞으로 이에 대한 많은 연구가 이루어져야할 것으로 판단된다.태에도 불구하고 [-wh]의미의 겹의문사는 병렬적 관계의 합성어가 아니라 내부구조를 지니지 않은 단순한 단어(minimal $X^{0}$ elements)로 가정한다. 즉, [+wh] 의미의 겹의문사는 동일한 구성요 소를 지닌 병렬적 합성어([$[W1]_{XO-}$ $[W1]_{XO}$ ]$

• Journal of Biosystems Engineering
• /
• v.14 no.1
• /
• pp.1-7
• /
• 1989

This study was carried out to develop a system and methodology to simulate the engine load variation occuring during agricultural field operations for a laboratory engine test. The system consisted of an electric dynamometer, an Apple II microcomputer, and a data acquisition and control system. Several pieces of instruments were utilized to measure various engine performance data. Both engine torque and engine speed were fully controlled by a computer program. The dynamic characteristics of the system were analyzed through a series of tests and the limitations on the load simulation test were presented. The results of the study are summarized as follows: 1. Engine speed and toque were controlled by a computer program. The use of a stepping motor and reduction gears enabled engine speed be controlled within 1 rpm. 2. The natural frequency of the dynamometer-engine system was found to be around 5 Hz, at which the load simulation would be impossible because of resonance. 3. For the harmonic inputs with the frequencies above the natural frequency, the signal attenuated too much and therefore the load simulation was impossible. 4. The step response of the system showed an overshoot of 24.5 percent and the settling time for 5 percent criterion was around 3 seconds. 5. When actual field test data are utilized for load simulation, a low-pass filter should be included to attenuate the frequency components around and above the natural frequency.

• Smart Media Journal
• /
• v.1 no.1
• /
• pp.48-52
• /
• 2012

A reliable test of offshore plant hold a key post in offshore engineering technology. The offshore self-supporting of process module design and basic design technology needs engineering verification based on the reliable test. And also reliable verification test data is very important. Therefore, verification test system for offshore installation simulation is necessary. This paper explains design of data acquisition system and control system based on the parameter of measured and controlled variable which is for establishing offshore installation simulation system.

• Journal of Information Technology and Architecture
• /
• v.9 no.3
• /
• pp.265-273
• /
• 2012

To improve M&S and SBA, it is important that their capability and maturity models should be developed. In general, capability and maturity models provide the standards for growth and improvement as well as the assessment on the organizational maturity level and the process capabilities, which are composed of a standard reference model and appraisal methods. In this paper, following introduction of a standard reference model for SBA in brief, we investigate some appraisal methods by survey and provide frameworks of appraisal method for SBA.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2000.05a
• /
• pp.952-955
• /
• 2000

Nowadays, Internet is so popular that we can easily access the remote site to search information and to communicate remote site and users. People who want to make a collaborate working environment can use JAVA, CORBA, and other internet programming tools like a Perl/XML. The mechanist are try to make the environment fur collaboration within design/manufacturing, simulation, remote sensing through TCP/IP And many industries and research institutions are working towards the agile manufacturing. This paper describes an internet-based real-Time remote monitoring system. The system consists of a hardware setup and a software interface. The hardware setup consists of a machine and its data acquisition hardware, while the software interface incorporates the data acquisition software, the server program, and the client program. The server program acts as the main interface between the data acquisition system and the internet technology. The client program is to be distributed to the remote users who want to monitor the machining status. The system has been demonstrated and verified for an industrial High-Speed Machine (HSM) especially measuring cutting force and acoustic emission. To share the signal, we make the WWW server and display its value. The system has been found to be highly efficient, reliable and accurate.

• Journal of the Society of Naval Architects of Korea
• /
• v.46 no.1
• /
• pp.43-56
• /
• 2009

The Korean navy has made many efforts to apply the concepts of PLM (Product Lifecycle Management) and M&S to its naval design and production. However, most of the efforts that have being applied to some acquisition processes, focused only on the element technologies without information models and data frameworks. This study discusses an information model of naval ships for advanced naval acquisitions. We introduce a naval ship product model, and it refers to the DPD (Distributed Product Description) concept of SBA (Simulation-Based Acquisition). To realize the product model concept, we design a data architecture and develop a Product Model Management System (PMMS) based on a PDM System. It is validated through the case study of building the product model of the battle ship that the PMMS has the applicability to effectively manage the naval ship acquisition data on the basis of a 3D product model.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.36 no.11
• /
• pp.1112-1120
• /
• 2008

The real-time distributed simulation at the present age concentrates on the construction of a system development environment in order to accomplish a synthetic battlefield environment connected with Live-Virtual-Constructive simulation and to realize the Simulation Based Acquisition which supports the life cycle of weapon system. Accordingly this paper describes the development environment of the UML modeling and simulation which integrates the system analysis and design methods performed during the conceptual design phase of the reconnaissance UAV system development. An integrated framework linked with the UML simulation and X-plane visualization is suggested to efficiently perform the system analysis and design, and finally the implementation contents, the analysis of experiment results and concluding remarks are described.

• Journal of KIISE:Computer Systems and Theory
• /
• v.36 no.2
• /
• pp.53-59
• /
• 2009

Simulation Based Acquisition(SBA) which pursues to use M&S in manner of integrated collaboration is being applied in defense acquisition. To accomplish SBA efficiently, reusability, reconfiguration and scalability of M&S components are important factors. To avoid constraints caused by coupling of components, PBA is designed to add and configure components easily by enabling independent interface and interaction among the components and provides common development infrastructure also. And PBA framework is implemented to support the development of a simulator which uses the PBA. It is expected that deployment of PBA framework as common development infrastructure can raise efficiency of M&S works.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.34 no.6C
• /
• pp.649-655
• /
• 2009

Mean acquisition time (MAT) is the most important performance measure for code acquisition systems, where a shorter MAT implies a better code acquisition performance. Keshavarzian and Salehi proposed the multiple-shift (MS) algorithm for code acquisition in optical code division multiple access (O-CDMA) systems. Performing two steps acquisition, the MS algorithm has a shorter MAT than that of the conventional serial-search (SS) algorithm. In this paper, we propose a rapid code acquisition algorithm for O-CDMA systems. By using an efficient combination of local signals, correlation value, and the sign of correlation value, the proposed algorithm can provide a shorter MAT compared with that of the MS algorithm. The simulation results show that the proposed algorithm presents a shorter MAT than that of the MS algorithm.