• 한국정밀공학회지
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• 제18권11호
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• pp.74-79
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• 2001

In this two-part paper, a virtual machine tool (VMT) is presented. In part 1, the analytical foundation of a virtual machining system, envisioned as the foundation for a comprehensive simulation environment capable of predicting the outcome of cutting processes, is developed. The VMT system purposes to experience the pseudo-real machining before real cutting with a CNC machine tool, to provide the proper cutting conditions for process planners, and to compensate or control the machining process in terms of the productivity and attributes of products. The attributes can be characterized with the machined surface error, dimensional accuracy, roughness, integrity and so forth. The main components of the VMT are cutting process, application, thermal behavior and feed drive modules. In part 1, the cutting process module is presented. The proposed models were verified experimentally and gave significantly better prediction results than any other method. The thermal behavior and feed drive modules are developed in part 2 paper. The developed models are integrated as a comprehensive software environment in part 2 paper.

• Smart Structures and Systems
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• 제14권2호
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• pp.247-266
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• 2014

Conventional cantilevered piezoelectric energy harvesters (PEHs) are usually fabricated with continuous electrode configuration (CEC), which suffers from the electrical cancellation at higher vibration modes. Though previous research pointed out that the segmented electrode configuration (SEC) can address this issue, a comprehensive evaluation of the PEH with SEC has yet been reported. With the consideration of delivering power to a common load, the AC outputs from all segmented electrode pairs should be rectified to DC outputs separately. In such case, theoretical formulation for power estimation becomes challenging. This paper proposes a method based on equivalent circuit model (ECM) and circuit simulation to evaluate the performance of the PEH with SEC. First, the parameters of the multi-mode ECM are identified from theoretical analysis. The ECM is then established in SPICE software and validated by the theoretical model and finite element method (FEM) with resistive loads. Subsequently, the optimal performances with SEC and CEC are compared considering the practical DC interface circuit. A comprehensive evaluation of the advantageous performance with SEC is provided for the first time. The results demonstrate the feasibility of using SEC as a simple and effective means to improve the performance of a cantilevered PEH at a higher mode.

• Advances in concrete construction
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• 제7권1호
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• pp.11-22
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• 2019

A comprehensive assessing approach for durability of reinforced concrete structures dealing with the corrosion process of rebar subjected to the attack of aggressive agent from environment was proposed in this paper. Corrosion of rebar was suggested in the form of combination of global corrosion and pitting. Firstly, for the purposed of considering the influence of rebar's radius, a type of Plane Corrosion Model (PCM) based on uniform corrosion of rebar was introduced. By means of FE simulation approach, global corrosion process of rebar regarding PCM and LCM (Linear Corrosion Model) was regressed and compared according to the data from Laboratoire $Mat{\acute{e}}riaux$ et $Durabilit{\acute{e}}$ des Constructions (LMDC). Secondly, pitting factor model of rebar in general descend law with corrosion degree was introduced in terms of existing experimental data. Finally, with the comprehensive numerical simulation, the durability of an existing arch bridge was studied in depth in deterministic way, including diffusion process and sectional strength of typical cross section of arch, crossbeam and deck slab. Evolution of structural capacity considering life-cycle rehabilitation strategy indicated the degradation law of durability of reinforced arch bridges.

• Nuclear Engineering and Technology
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• 제55권2호
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• pp.493-505
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• 2023

Comprehensive condition monitoring of large industry systems such as nuclear power plants (NPPs) is essential for safety and maintenance. In this study, we developed novel system-scale diagnostic technology based on deep-learning and IR thermography that can efficiently and cost-effectively classify system conditions using compact Raspberry Pi and IR sensors. This diagnostic technology can identify the presence of an abnormality or accident in whole system, and when an accident occurs, the type of accident and the location of the abnormality can be identified in real-time. For technology development, the experiment for the thermal image measurement and performance validation of major components at each accident condition of NPPs was conducted using a thermal-hydraulic integral effect test facility with compact infrared sensor modules. These thermal images were used for training of deep-learning model, convolutional neural networks (CNN), which is effective for image processing. As a result, a proposed novel diagnostic was developed that can perform diagnosis of components, whole system and accident classification using thermal images. The optimal model was derived based on the modern CNN model and performed prompt and accurate condition monitoring of component and whole system diagnosis, and accident classification. This diagnostic technology is expected to be applied to comprehensive condition monitoring of nuclear power plants for safety.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2021년도 춘계학술대회
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• pp.657-660
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• 2021

영상정보처리기기(CCTV)는 민감 정보를 수집, 전송, 저장하는 데 있어서 관리적, 물리적, 기술적 측면에서 포괄적으로 보안관리가 이뤄져야 한다. 이를 위해 영상정보처리에 관련된 암호기술, 기술인증, 보호기술, 보안장비에 대한 적용 기준이 필요하다. 본 논문에서는 영상정보처리기기에 관련된 다양한 보안기술, 인증제도를 분석하여 영상정보처리기기의 구축 및 운영에 적용하여 포괄적 보안관리를 위한 암호·인증·보호·체계(CCPS; Cryptography·Certification·Protection·System) 모델을 제안한다.

• 대한안전경영과학회지
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• 제10권2호
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• pp.211-216
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• 2008

Using this model, SN ratio of taguchi method for each of subjective factors as well as values of weights are used in this comprehensive positioning method for product. A example is presented to illustrate the model and to show a rank reversal when compared to a model that eliminates the highest and lowest customers' values allocating the weights and the subjective factors.

• 정보기술과데이타베이스저널
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• 제8권2호
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• pp.115-135
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• 2001

The objective of this paper is to develop a knowledge assets measurement model in Korea. There are relatively many researches on measuring knowledge assets of an organization. These previous researches, however, lack of comprehensive view of knowledge management and view of Korean organizational culture. We surveyed and analyzed previous researches, and found common factors to measure knowledge assets. We developed an updated version of knowledge assets index. The developed model has been validated for its fitness with real data of Korean companies. The result of this research can be used as a measurement tool for knowledge assets of public institutions as well as private companies.

• 한국지능시스템학회:학술대회논문집
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• 한국퍼지및지능시스템학회 1993년도 Fifth International Fuzzy Systems Association World Congress 93
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• pp.1238-1241
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• 1993

A fuzzy mathematical model is presented that can be applied to support the inspection of organizations by an internal or external evaluation group. The model offers the opportunity to deal with the situation of common practice in which such evaluations are considered as a time series rather than single events. A hypothetical but realistic example is given to illustrate the computational procedure involved.

• 농촌계획
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• 제22권4호
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• pp.25-36
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• 2016

The purpose of this study is to construct a quantitative evaluation method that can analyze the policy effectiveness with the construction of a implicit composite index incorporating spatial econometrics models. In order to propose a methodological framework for the program evaluation, this study conducts an empirical analysis with the application of the Comprehensive Rural Village Development Project (CRVDP) which explicitly claims to achieve comprehensive goal of community development. The present study pays particular attention to quantifying the composite evaluation index and drawing net effect through the application of a series of spatial econometrics models. The spatial unit of the analysis is drawn at Eup-Myeon level in rural areas in Korea, and the time horizon is in between 2005 and 2010. We utilize the Korean Agricultural Census data in 2005 and 2010. Three steps of methodological processes are needed to satisfy the objective of the present study. First, we apply factor analysis to construct the composite index that represents comprehensive settlement environment in rural area. The index should be matched with the main objective of the CRVDP. Second, we apply the derived index to a series of spatial econometrics model as dependent variable. Lastly, utilizing the estimated coefficients of the econometrics models, we apply decomposition technique to estimate CRVDP's net effect from both cross-sectional and longitudinal perspectives. We find that the results of the decomposition analysis by the execution of the CRVDP are positively associated with the explicit object of the project.

• 한국문헌정보학회지
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• 제55권1호
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• pp.493-519
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• 2021

이 연구의 목적은 연구자에게 끊김 없는 학술정보서비스를 제공하기 위하여 식별자를 중심으로 한 종합링킹체제를 구현할 수 있는 방안을 제시하는 것이다. 해당 목적을 달성하기 위하여 KISTI 소속의 5개 센터 및 1개 사무국 소속 17명의 연구자와 인터뷰를 진행하였다. 인터뷰 내용은 학술정보서비스 DB의 식별자 구축 및 관리 현황에 대한 것으로 면담 결과, 국내 논문 DB의 경우 KOI 등의 식별자에 대한 식별률은 높았지만 해외논문의 경우, DOI를 제외하고 ORCID 등 글로벌 식별자에 대한 식별률은 낮은 것으로 나타났다. 이러한 문제를 해결하기 위해 본 논문에서는 식별자를 중심으로 한 종합링킹체제 모델을 구축하기 위한 종합링킹체제 공동활용협의회를 제안하였다. 공동활용협의회는 국내 학술정보유통기관을 중심으로 구성될 것이며 구성된 협의회에서는 해외 식별자를 수집하여 식별자 연계를 통한 새로운 서비스가 발굴되고 구현될 것으로 기대한다.