• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2008년도 정기 학술대회
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• pp.241-246
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• 2008

Design of a high-speed railway line requires collaboration of heterogeneous application systems and of engineers with different background. Object-based 3D models with metadata can be a shared information model for the effective collaborative design. In this paper, railway infrastructure information model is proposed to enable integrated and inter-operable works throughout the life-cycle of the railway infrastructures, from planning to maintenance. In order to develop the model, object-based 3-D models were built for a 10km railway among Korea high-speed railway lines. The model has basically three information layers for designers, contractors and an owner, respectively. Prestressed concrete box-girders are the most common superstructure of bridges. The design information layer has metadata on requirements, design codes, geometry, analysis and so on. The construction layer has data on drawings, real data for material and products, schedules and so on. The maintenance layer for the owner has the final geometry, material data, products and their suppliers and so on. These information has its own data architecture which is derived from similar concept of product breakdown structure(PBS) and work breakdown structure(WBS). The constructed RIIM for the infrastructures of the high-speed railway was successfully applied to various areas such as design check, structural analysis, automated estimation, construction simulation, virtual viewing, and digital mock-up. The integrated information model can realize virtual construction system for railway lines and dramatically increase the productivity of the whole engineering process.

• 한국자동차공학회논문집
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• 제8권4호
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• pp.169-176
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• 2000

Longitudinal and lateral forces acting on tires are known to be closely related to the tract-ability braking characteristics handling stability and maneuverability of ground vehicles. In thie paper in order to develop tire force monitoring systems a monitoring model is proposed utilizing not only the vehicle dynamics but also the roll motion. Based on the monitoring model three monitoring systems are developed to estimate the tire force acting on each tire. Two monitoring systems are designed utilizing the conventional estimation techniques such as SMO(Sliding Mode Observer) and EKF(Extended Kalman Filter). An additional monitoring system is designed based on a new SKFMEC(Scaled Kalman Filter with Model Error Compensator) technique which is developed to improve the performance of EKF method. Tire force estimation performance of the three monitoring systems is compared in the Matlab simulations where true tire force data is generated from a 14 DOF vehicle model with the combined-slip Magic Formula tire model. The built in our Lab. simulation results show that the SKFMEC method gives the best performance when the driving and road conditions are perturbed.

• 한국음향학회지
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• 제18권8호
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• pp.75-83
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• 1999

본 논문에서는 음성합성의 억양 제어를 위한 새로운 F0 궤적 모델을 제안한다. 제안한 모델은 발성된 문장의 F0 궤적을 중첩가산되는 사건들로 분해하고, 각 사건들을 가우시안 종모양의 사건함수로 모델링한다. 그리고 제안한 모델을 위한 파라미터 추정 알고리즘을 제시한다. 제안한 모델은 특정한 음운론적 지식에 기반하지 않았으며, F0 궤적의 분석단계와 합성단계에 모두 사용 가능하다. 제안한 모델의 성능평가를 위해 다양한 장르에서 추출한 여러 형태의 500문장의 코퍼스를 구축하고, 이를 전문 아나운서에게 발성하게 하여 구축한 음성코퍼스로 실험한 결과, 원음성의 F0 궤적과 제안한 모델에 의해 합성된 F0 궤적의 평균 제곱 오류근이 7.87Hz이었다.

• Industrial Engineering and Management Systems
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• 제12권3호
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• pp.207-223
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• 2013

Revenue management (RM) has been widely used to model products characterized as perishable. Classical RM model assumed that price is the sole factor in the model. Thus price adjustment becomes a crucial and costly factor in business. In this paper, an optimal pricing model is developed based on minimization of soft customer cost, one kind of price adjustment cost and is solved by Lagrange multiplier method. It is formed by expected discounted revenue/bid price integrating quantity-based RM and pricing-based RM. Quantity-based RM consists of two capacity models, namely, booking limit and overbooking. Booking limit, built by assuming uncertain customer arrival, decides the optimal capacity allocation for two market segments. Overbooking determines the level of accepted order exceeding capacity to anticipate probability of cancellation. Furthermore, pricing-based RM models occupancy/demand rate influenced by internal and competitor price changes. In this paper, a mathematical model based on game theoretic approach is developed for two conditions of deterministic and stochastic demand. Based on the equilibrium point, the best strategy for both hotels can be determined.

• 대한조선학회논문집
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• 제29권2호
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• pp.30-37
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• 1992

선체는 매우 복잡한 구조물이므로 설계 및 생산의 효율적인 수행을 위하여 선체구조의 모델링에 의한 작업이 필수적이다. 선체모델 구축에 있어서 구조면의 모델링은 초기선형정의에서부터, 선각정보처리, 구획배치, 의장설계, 배관설계, 구조해석 등 선체관련분야와 직접 연관된다. 본 연구에서는 구조면의 효과적인 모델링을 위하여 구조면들간의 위상학적인 자료구조를 구성하므로써 선체구조의 기하학적 정보를 설계의 단계에 따라 발전시켜 나가고 효율적으로 변경시킬 수 있도록 하였다. 본 연구에서 수행된 구조면의 모델링은 선체설계에서부터 생산에 이르기까지 일관된 정보처리를 위한 통합선체모델(Unified Hull Model)구축의 기초가 될 것이다. 구축된 모델의 가시화를 위하여 컴퓨터그래픽스를 이용하여 선체모델을 실물감 있게 표현하였다.

• 한국유체기계학회 논문집
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• 제16권6호
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• pp.32-39
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• 2013

In the present study, three-dimensional aerodynamic optimization of high pressure turbine nozzle for turbofan engine was performed. For this, Kriging surrogate model was built and refined iteratively by supplying additional experimental points until the surrogate model and CFX result has effective difference on objective function. When the surrogate model satisfied this reliability condition and developed enough, optimum point was investigated. Commercial program PIAnO was used for optimization process and evolutionary algorithm was used for searching optimum point. As a result, difference between estimated value from Kriging surrogate model and CFD result converges within 0.01% and the optimized nozzle shape has 0.83% improved aerodynamic efficiency.

• Journal of Information Technology Applications and Management
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• 제20권3호
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• pp.143-167
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• 2013

The main propose of this research is to examine the performances in ERP introduced enterprises by utilizing BSC model proposed by Kaplan and Norton [1992], to realize this goals, a theoretical review on ERP, BSC, and other related issues is performed in advance, accordingly, research model was generated. In conceptual model analysis, we focused on casual relationships among four performance measurement indicators after introduction of ERP proposed by Kaplan and Norton [2000]. To test the model, structural equation modeling is employed to analyze data collected from 164 enterprises which have introduced ERP for more than 1 year. Survey respondents were confined within the representatives of each enterprise's ERP. Hypotheses proposed in our research are tested by covariance structure model, results are listed as follow : First, learning and growth performance is significant factors for improving both internal process performance and customer performance; second, process performance has a positive impact on customer performance third, despite that customer performance is positively related to financial performance, no direct relationship is found between internal process performance and financial performance, an indirect relationship is built through intermediate medium of customer performance. Based upon these results, we discuss implications at the latter part of paper. Meanwhile, we also provide research limitations, and future research in the final section.

• 한국철도학회논문집
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• 제17권4호
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• pp.307-312
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• 2014

본 연구는 중앙선의 여객수송수요를 효율적으로 예측하기 위한 방법으로 계절성 요인을 고려한 ARIMA 모형을 제안하였다. 특히, 최근의 관광수요를 반영하기 위하여 2013년 4월 개통되어 운행되고 있는 중부내륙권 관광전용열차(O-train, V-train)의 수요를 포함하여 예측모형을 구축하였다. 이를 위하여 2005년 1월부터 2013년 7월까지의 월별 시계열 데이터(103개)를 사용하여 최적의 모형을 선정하였으며 예측결과 중앙선의 여객 수송수요는 지속적으로 증가할 것으로 나타났다. 구축된 모형은 중앙선의 단기수요를 예측하는데 활용이 가능하다.

• International Journal of Computer Science & Network Security
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• 제21권12호
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• pp.9-20
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• 2021

Abstraction applied in computer networking hides network details behind a well-defined representation by building a model that captures an essential aspect of the network system. Two current methods of representation are available, one based on graph theory, where a network node is reduced to a point in a graph, and the other the use of non-methodological iconic depictions such as human heads, walls, towers or computer racks. In this paper, we adopt an abstract representation methodology, the thinging machine (TM), proposed in software engineering to model computer networks. TM defines a single coherent network architecture and topology that is constituted from only five generic actions with two types of arrows. Without loss of generality, this paper applies TM to model the area of network monitoring in packet-mode transmission. Complex network documents are difficult to maintain and are not guaranteed to mirror actual situations. Network monitoring is constant monitoring for and alerting of malfunctions, failures, stoppages or suspicious activities in a network system. Current monitoring systems are built on ad hoc descriptions that lack systemization. The TM model of monitoring presents a theoretical foundation integrated with events and behavior descriptions. To investigate TM modeling's feasibility, we apply it to an existing computer network in a Kuwaiti enterprise to create an integrated network system that includes hardware, software and communication facilities. The final specifications point to TM modeling's viability in the computer networking field.

• 디지털산업정보학회논문지
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• 제19권1호
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• pp.119-127
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• 2023

Recently, deep learning has been used in the development of various institutional devices and services to help the visually impaired people in their daily lives. This is because not only are there few products and facility guides written in braille, but less than 10% of the visually impaired can use braille. In this paper, we propose a system that recognizes beverage cans in real time and outputs the beverage can name with sound for the convenience of the visually impaired. Five commercially available beverage cans were selected, and a CNN model and a YOLO model were designed to recognize the beverage cans. After augmenting the image data, model training was performed. The accuracy of the proposed CNN model and YOLO model is 91.2% and 90.8%, respectively. For practical verification, a system was built by attaching a camera and speaker to a Raspberry Pi. In the system, the YOLO model was applied. It was confirmed that beverage cans were recognized and output as sound in real time in various environments.