• 제어로봇시스템학회논문지
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• 제12권8호
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• pp.834-841
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• 2006

Recently, many enterprises are installing AMSs(Automated Manufacturing Systems) for their competitive advantages. As the level of automation increases, proper design and validation of control logic is a imperative task for the successful operation of AMSs. However, current discrete event simulation methods mainly focus on the performance evaluation. As a result, they lack the modeling capabilities for the detail logic of automated manufacturing system controller. Proposed in this paper is a method of validation of the controller logic for automated material handling system using an object-oriented design and simulation. Using this method, FA engineers can validate the controller logic easily in earlier stage of system design, so they can reduce the time for correcting the logic errors and enhance the productivity of control program development Generated simulation model can also be used as a communication tool among FA engineers who have different experiences and disciplines.

• 한국농공학회논문집
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• 제66권1호
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• pp.1-13
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• 2024

This study assessed the efficacy of improving the accuracy of reservoir water level prediction models by employing automated machine learning models and efficient cross-validation methods for time-series data. Considering the inherent complexity and non-linearity of time-series data related to reservoir water levels, we proposed an optimized approach for model selection and training. The performance of twelve models was evaluated for the Obong Reservoir in Gangneung, Gangwon Province, using the TPOT (Tree-based Pipeline Optimization Tool) and four cross-validation methods, which led to the determination of the optimal pipeline model. The pipeline model consisting of Extra Tree, Stacking Ridge Regression, and Simple Ridge Regression showed outstanding predictive performance for both training and test data, with an R² (Coefficient of determination) and NSE (Nash-Sutcliffe Efficiency) exceeding 0.93. On the other hand, for predictions of water levels 12 hours later, the pipeline model selected through time-series split cross-validation accurately captured the change pattern of time-series water level data during the test period, with an NSE exceeding 0.99. The methodology proposed in this study is expected to greatly contribute to the efficient generation of reservoir water level predictions in regions with high rainfall variability.

• 경영정보학연구
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• 제7권1호
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• pp.81-96
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• 2005

웹사이트의 사용이 일상화 되어감에 따라 컴퓨터를 다루기 힘든 장애인 및 노인들의 웹사이트 정보에 대한 접근성이 강조되고 있다. 노인과 장애인의 정보화 격차를 해소하기 위해 웹 접근성에 대한 인식이 중요시되고 있으나 한국에서는 이와 관련된 분야의 연구가 미미한 실정이다. 본 연구에서는 지금까지의 웹 접근성에 관한 선행 연구와 접근성 평가도구를 분석하여 기존의 웹 접근성 평가의 한계를 지적하고 이를 해결하기 위한 웹사이트 접근성 평가모델을 제안하였다. 특히 웹 접근성 평가방법을 다각적으로 시도하기 위해 1차 평가에서는 자동화 평가도구인 A-Prompt를 이용하였고, 2차 평가에서는 1차 결과를 중심으로 소스분석과 HPR(Home Page Reader) 스크린리더를 통한 수작업(메뉴얼) 평가를 실시하였다. 평가결과를 바탕으로 접근성 오류율을 계산하여 한국과 미국정부 웹사이트의 접근성을 비교분석하고 평가결과를 통해 시사점과 개선방안을 제시하였다.

• 인터넷정보학회논문지
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• 제10권4호
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• pp.105-113
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• 2009

특성 모델(Feature Model)은 소프트웨어 제품 라인 개발 시 도메인 공학 단계에서 제품들 사이의 공통점과 차이점을 모델링하는데 널리 사용된다. 특성 모델의 오류 또는 불일치성에 대한 발견 및 수정은 성공적인 소프트웨어 제품 라인 공학을 위해서 필수적이다. 특성 모델의 검증을 효과적으로 수행하기 위해서는 자동화된 도구의 도움이 필요하다. 본 논문에서는 JESS 규칙 기반 시스템을 이용하여 특성 모델의 유효성을 검증하는 기법을 기술하고 이를 이용한 특성 모델 검증 도구를 제안한다. 본 논문의 도구는 특성 모델링 작업 시 실시간으로 특성 모델을 검증하여 오류의 존재 여부와 오류의 원인에 대한 설명을 제공함으로써 오류 없는 특성 모델을 생성할 수 있도록 해 준다. 특성 모델 검증 기법에 규칙 기반 시스템을 이용한 경우는 본 논문이 최초의 시도로 사료된다.

• 컴퓨터교육학회논문지
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• 제7권4호
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• pp.51-60
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• 2004

본 논문은 통계청에서 실시하는 인구 주택 총조사와 사업체 기초통계조사 시 실시되는 수작업에 의한 표준 산업/직업 코드 분류 시 발생하는 막대한 비용과 시간, 일관성의 결여 등을 해소하기 위한 표준 산업/직업 코드 자동 분류 시스템을 제안한다. 제안한 시스템은 정보 검색 기법과 문서 분류 기법을 이용하여 자연어로 기술된 레코드를 입력 받아 입력 레코드에 해당하는 분류 코드를 생성한다. 수작업으로 올바른 코드가 할당되어 있는 산업 분류 레코드 46,762개와 직업 분류 코드 36,286개를 이용하여 10-fold cross-validation evaluation을 수행한 결과, 제안한 시스템은 완전 자동 모드에서 2수준의 산업 분류에 대해서 87.08%, 5수준에 대해서는 66.08%의 생성률을 보였으며 반자동 모드에서는 각각 99.10%와 92.88%의 성능을 보였다. 직업 분류 코드에 대한 성능은 산업 분류 코드에 대한 성능보다는 약간 저하된 성능을 보였다. 제안한 시스템은 아직 수작업을 완전히 대체할 수 있는 완전 자동 분류기로서는 많은 개선의 여지를 가지고 있지만 수작업을 최소화할 수 있는 반자동 도구나 수작업의 정확도를 검증할 수 있는 보조 도구로써 충분히 활용될 수 있을 것으로 기대된다.

• Journal of information and communication convergence engineering
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• 제6권1호
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• pp.59-63
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• 2008

The methods or algorithms which can accelerate simulation speed became of great importance, as the modeling and simulation methodology for discrete event systems is used in many areas such as model validation/verification and performance evaluation. This paper proposes a tool named, DEVSIF composer. The tool is made of an automated compiled simulation technology and it builds a new composed model which can be executed much fast by composing the component models together. Models are described by our new specification language DEVSIF, which is compatible with object-oriented language and supports representation of a hierarchical model structure. Experimental results demonstrates that DEVSIF composer enhances the simulation speed of a transformed DEVS model 5 times faster than that of the original ones in average.

• Journal of applied mathematics & informatics
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• 제31권3_4호
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• pp.425-441
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• 2013

In literature, several strong designated verifier signature (SDVS) schemes have been devised using elliptic curve bilinear pairing and map-topoint (MTP) hash function. The bilinear pairing requires a super-singular elliptic curve group having large number of elements and the relative computation cost of it is approximately two to three times higher than that of elliptic curve point multiplication, which indicates that bilinear pairing is an expensive operation. Moreover, the MTP function, which maps a user identity into an elliptic curve point, is more expensive than an elliptic curve scalar point multiplication. Hence, the SDVS schemes from bilinear pairing and MTP hash function are not efficient in real environments. Thus, a cost-efficient SDVS scheme using elliptic curve cryptography with pairingfree operation is proposed in this paper that instead of MTP hash function uses a general cryptographic hash function. The security analysis shows that our scheme is secure in the random oracle model with the hardness assumption of CDH problem. In addition, the formal security validation of the proposed scheme is done using AVISPA tool (Automated Validation of Internet Security Protocols and Applications) that demonstrated that our scheme is unforgeable against passive and active attacks. Our scheme also satisfies the different properties of an SDVS scheme including strongness, source hiding, non-transferability and unforgeability. The comparison of our scheme with others are given, which shows that it outperforms in terms of security, computation cost and bandwidth requirement.

• 농업과학연구
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• 제48권3호
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• pp.629-642
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• 2021

Land-use change has an important role in the hydrologic characteristics of watersheds because it alters various hydrologic components such as interception, infiltration, and evapotranspiration. For example, rapid urbanization in a watershed reduces infiltration rates and increases peak flow which lead to changes in the hydrologic responses. In this study, a physical hydrologic model the soil and water assessment tool (SWAT) was used to assess long-term continuous daily streamflow corresponding to land-use changes that occurred in the Naesungchun river watershed. For a 30-year model simulation, 3 different land-use maps of the 1990s, 2000s, and 2010s were used to identify the impacts of the land-use changes. Using SWAT-CUP (calibration and uncertainty program), an automated parameter calibration tool, 23 parameters were selected, optimized and compared with the daily streamflow data observed at the upstream, midstream and downstream locations of the watershed. The statistical indexes used for the model calibration and validation show that the model performance is improved at the downstream location of the Naesungchun river. The simulated streamflow in the mainstream considering land-use change increases up to -2 - 30 cm compared with the results simulated with the single land-use map. However, the difference was not significant in the tributaries with or without the impact of land-use change.

• Advances in Automotive Engineering
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• 제1권1호
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• pp.123-141
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• 2018

Hardware-in-the-loop (HiL) simulation is a very powerful tool to design, test and verify automotive control systems. However, well-validated and high degree of freedom vehicle models have to be utilized in these simulations in order to obtain realistic results. In this paper, a vehicle dynamics model developed in the Carsim Real Time program environment and its validation has been performed using experimental results. The developed Carsim real time model has been employed in the Tofas R&D hardware-in-the-loop simulator. Experimental and hardware-in-the-loop simulation results have been compared for the standard FMVSS No. 126 test and the results have been found to be in good agreement with each other. Two electronic stability control (ESC) algorithms, named the Basic ESC and the Integrated ESC, taken from the earlier work of the authors have been tested and evaluated in the hardware-in-the-loop simulator. Different evaluation methods have been formulated and used to compare these ESC algorithms. As a result, the Integrated ESC system has been shown superior performance as compared to the Basic ESC algorithm.

• 한국농공학회논문집
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• 제60권6호
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• pp.65-71
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• 2018

The Long-Term Hydrologic Impact Assessment (L-THIA) model is a quick and straightforward analysis tool to estimate direct runoff and nonpoint source pollution. L-THIA was originally implemented as a spreadsheet application. GIS-based versions of L-THIA have been developed in ArcView 3 and upgraded to ArcGIS 9. However, a major upgrade was required for L-THIA to operate in the current version of ArcGIS and to provide more options in runoff and NPS estimation. An updated L-THIA interfaced with ArcGIS 10.0 and 10.1 has been developed in the study as an ArcGIS Desktop Tool. The model provides a user-friendly interface, easy access to the model parameters, and an automated watershed delineation process. The model allows use of precipitation data from multiple gauge locations for the watershed when a watershed is large enough to have more than one precipitation gauge station. The model estimated annual direct runoff well for our study area compared to separated direct runoff in the calibration and validation periods of ten and nine years. The ArcL-THIA, with a user-friendly interface and enhanced functions, is expected to be a decision support model requiring less effort for GIS processes or to be a useful educational hydrology model.