• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2010년도 추계학술대회
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• pp.183-186
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• 2010

본 논문은 해상전자장비의 인터페이스(Interface) 표준인 NMEA(National Marine Electronics Association) 기반의 해상전자장비 표준 프로토콜과 선교 항해당직 경보시스템(BNWAS : Bridge Navigational Watch Alarm System)에 관한 표준을 따라 안정적이고 Real-Time을 지원하는 FlexRay 기반으로 구현하고자 한다. 기존의 선박통신에 사용되는 NMEA 통신 프로토콜과 BNWAS은 RS-232, RS-422 등으로 구현하고 있다. 때문에 통신에 대한 안정성 및 신뢰도를 보장하기 어려운 문제점이 있다. 이러한 문제를 해결하기 위하여 FlexRay 통신 규격들을 적용하여 전송 중 데이터의 손실되거나 오류가 생기지 않도록 선박내 통신에 사용할 수 있는 차세대 FlexRay 프로토콜을 사용하여 안정성과 신뢰도를 제시하고자 한다.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2006년도 정기 학술대회 논문집
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• pp.208-215
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• 2006

This study provides a new operation strategy which can guarantee the data consistency of engineering information among the various intelligent information systems. We present the strategies for the operation of bridges engineering information and the construction methodology of integrated database. The two core standard techniques are adopted to construct the integrated database. One of these standards is the Standard for the Exchange of Product Model Data (STEP) for CAD/CAE information and the other is the Extensible Markup Language (XML) for engineering document information. This study can transform a document me into a data type for web-based application modules which assist end-users in searching and retrieval of engineering document data. In addition, relaying algorithm is developed to integrate the two different information, e.g. CAD/CAE information and engineering document information. The pilot application modules for management and maintenance of existing bridge are also developed to show application of the strategy.

• Structural Monitoring and Maintenance
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• 제4권4호
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• pp.331-350
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• 2017

Based on the alternative stabilization diagram by varying the time lag parameter in the stochastic subspace identification analysis, this study aims to investigate the measurements from several cases of civil structures for extending the applicability of a recently noticed criterion to ensure stable identification results. Such a criterion demands the time lag parameter to be no less than a critical threshold determined by the ratio of the sampling rate to the fundamental system frequency and is firstly validated for its applications with single measurements from stay cables, bridge decks, and buildings. As for multiple measurements, it is found that the predicted threshold works well for the cases of stay cables and buildings, but makes an evident overestimation for the case of bridge decks. This discrepancy is further explained by the fact that the deck vibrations are induced by multiple excitations independently coming from the passing traffic. The cable vibration signals covering the sensor locations close to both the deck and pylon ends of a cable-stayed bridge provide convincing evidences to testify this important discovery.

• Smart Structures and Systems
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• 제6권3호
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• pp.309-333
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• 2010

Civil infrastructure, in both its construction and maintenance, represents the largest societal investment in this country, outside of the health care industry. Despite being the lifeline of US commerce, civil infrastructure has scarcely benefited from the latest sensor technological advances. Our future should focus on harnessing these technologies to enhance the robustness, longevity and economic viability of this vast, societal investment, in light of inherent uncertainties and their exposure to service and even extreme loadings. One of the principal means of insuring the robustness and longevity of infrastructure is to strategically deploy smart sensors in them. Therefore, the objective is to develop novel, durable, smart sensors that are especially applicable to major infrastructure and the facilities to validate their reliability and long-term functionality. In some cases, this implies the development of new sensing elements themselves, while in other cases involves innovative packaging and use of existing sensor technologies. In either case, a parallel focus will be the integration and networking of these smart sensing elements for reliable data acquisition, transmission, and fusion, within a decision-making framework targeting efficient management and maintenance of infrastructure systems. In this paper, prudent and viable sensor and health monitoring technologies have been developed and used in several large structural systems. Discussion will also include several practical bridge health monitoring applications including their design, construction, and operation of the systems.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2008년도 정기 학술대회
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• pp.544-547
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• 2008

In 1990, Korea building contractors were indifferent maintenance management cause focus on completion of construction before construction collapsed. Currently, structures monitoring systems are restrictive on large structures. Structures monitoring systems are limited many old and small structures in the whole nation. Recently, we make efforts application Ubiquitous technology as like sensor, sensor network system, and wireless communication system in construction. This paper applies bridge management system using Ubiquitous skill which is real-time monitoring report offering system.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2001년도 춘계학술대회 논문집
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• pp.284-287
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• 2001

This paper presents the robust control simulation of a composite beam using self-sensing actuators(SSA). The self-sensing actuator is a new concept for intelligent material, where a single piezoelectric element simultaneously functions as both a sensor and an actuator. In a practical implementation of the self-sensing actuator an electrical bridge circuit is used to measure strain. The circuit could provide significant information about strain in the element if it were well-balanced. Our aim is design a robust controller which guarantees that the performance of a self-sensing actuator is robust against perturbation of the bridge balance and to confirm the advantages of this technique. Simulation results show that the self-sensing actuator driven by the designed controller exhibits excellent performance in suppressing the vibration of a composite beam.

• 한국소음진동공학회논문집
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• 제19권5호
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• pp.523-529
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• 2009

Smart sensor is known as intelligent sensor, it is different with other conventional sensors in the case of intelligent system embedded on it. Smart sensor has many benefits e.g. low-cost in usage, self-decision and self-diagnosis abilities. This sensor consists of perception element(sensing element), signal processing and technology of communication. In this work, a bridge and structure of smart sensor has been investigated to be capable to condition monitoring routine. This investigation involves low power consumption, software programming, fast data acquisition ability, and authoritativeness warranty. Moreover, this work also develops smart sensor to be capable to perform high sampling rate, high resolution of ADC, high memory capacity, and good communication for data transfer. The result shows that the developed smart sensor is promising to be applied to various industrial fields.

• Asia pacific journal of information systems
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• 제9권2호
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• pp.19-37
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• 1999

Computer aided process planning(CAPP) is a key for implementing CIM. It is bridge between CAD and CAM and translates the design information into manufacturing instructions. Generally, manufacturing is an area where intelligent systems will not be able to rely on methods requiring formalized knowledge. Manufacturing lacks a body of knowledge that is specific, formalized, and rigorous, and which can be coded as rules or procedures. Thus expertise in manufacturing is developed over a period of many years. Case-based reasoning(CBR) offers a new approach for developing intelligent system. In the case-based approach the problem solving experience of the experts is encoded in the form of cases. CBR's retrieval process can be divided to two step. The first step is matching step, and the second step is selection step. For selecting base case, new preference heuristics were introduced using similarity concept. Similarity concept has three has three dimensions, i.e. entity similarity, structural similarity, and goal similarity. In this paper, bolt's process planning was selected an application domain. Following the test result, the new preference heuristics were approved as a useful procedure in CAPP.

• 한국지능시스템학회:학술대회논문집
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• 한국퍼지및지능시스템학회 2002년도 춘계학술대회 및 임시총회
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• pp.10-13
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• 2002

본 연구에서는 다기능 휠체어 시스템을 개발하기 위해 제어부를 16bit의 마이크로 프로세서인 80C196KC 사용하였고, 조이스틱을 통해서 된 시스템을 제어하는 것을 구현하였다. 전체시스템은 제작된 전동 휠체어 기본 Plant를 사용하였으며, 모터에서 Encoder로 입력받아 MCU를 통해서 휠체어 회전수를 이용하여 제어시켰다. 휠체어 모터의 제어 방법은 PWM(Pulse Width Mudulation)을 이용하였으면, 여기에 H-브릿지 회로를 구성하였다. 조이스틱을 사람의 손으로 제어하는데 있어서 조이스틱 위치 변화에 따른 전동휠체어에 부착된 DC모터 동작을 퍼지 제어 알고리즘을 사랑하였으며, DC모터의 속력과 방향을 제어하고 아울러 위치 정보까지도 제어할 누 있게끔 하였다.

• 전력전자학회논문지
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• 제26권5호
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• pp.325-333
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• 2021

A 3 kW grid-tied PV inverter with Gallium nitride high-electron mobility transistor (GaN HEMT) for domestic commercialization was developed using boost converter and full-bridge inverter with LCL filter topology. Recently, many GaN HEMTs are manufactured as surface mount packages because of their lower parasitic inductance characteristic than standard TO (transistor outline) packages. A surface mount packaged GaN HEMT releases heat through either top or bottom cooling method. IGOT60R070D1 is selected as a key power semiconductor because it has a top cooling method and fairly low thermal resistances from junction to ambient. Its characteristics allow the design of a 3 kW inverter without forced convection, thereby providing great advantages in terms of easy maintenance and high reliability. 1EDF5673K is selected as a gate driver because its driving current and negative voltage output characteristics are highly optimized for IGOT60R070D1. An LCL filter with passive damping resistor is applied to attenuate the switching frequency harmonics to the grid-tied operation. The designed LCL filter parameters are validated with PSIM simulation. A prototype of 3 kW PV inverter with GaN HEMT is constructed to verify the performance of the power conversion system. It achieved high power density of 614 W/L and peak power efficiency of 99% for the boost converter and inverter.