• Transactions of the Korean Society of Automotive Engineers
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• v.8 no.6
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• pp.208-219
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• 2000

In this study, static axial crush tests were performed with the new aluminum/GFRP hybrid tube. Glass/Epoxy prepregs were wrapped around an aluminum tube and co-cured. The failure of the hybrid tube was stable and progressive without trigger mechanism, and specific energy absorption was increased to the maximum of 33% in comparison with the aluminum tube. Effective energy absorption is possible for an inner aluminum tube because a wrapped composite tube constrains the deflection of an aluminum tube. The failure of a hybrid composite tube was stable without trigger mechanism because the inner aluminum tube could play the role of the crack initiator and controller. Mean crushing load could be calculated by modifying the plastic hinge collapse model for hybrid materials. The predicted results by this analytical model showed good agreement with the experimental results. It can be said that Aluminum/Glass-Epoxy hybrid tube is suitable for the vehicle front structure because this hybrid tube shows effective energy absorption, easy production, and simple application capability for RTM process.

• Journal of Biomedical Engineering Research
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• v.26 no.2
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• pp.65-71
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• 2005

The main obstacles for adopting a mobile health information system to existing hospital information system are the redundancy of clinical data and the additional workload for implementing the new system. To obtain a seamless communication and to reduce the workload of implementation, an easy and simple implementation strategy is required. We propose a mobile clinical information system (MobileMed) which is specially designed for the easy implementation. The key elements of MobileMed are a smart interface, an HL7 message server, a central clinical database (CCDB), and a web server. The smart interface module transfers the key information to the HL7 message server as new clinical tests data is recorded in the existing laboratory information system. The HL7 message server generates the HL7 messages and sends them to the CCDS. As a central database the CCDS collects the HL7 messages and presents them to the various mobile devices such as PDA. Through this study we might conclude that the architecture for the mobile system will be efficient for real-time data communication, and the specially designed interface will be an easy tool for implementing the mobile clinical information system.

• Journal of the Korean Operations Research and Management Science Society
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• v.22 no.2
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• pp.79-97
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• 1997

Many dispatching rules have been developed for the on-line control of product flow in a job shop. The introduction of a flexible manufacturing system (FMS) has added a new requirement to classical job shop control problem : the selection of machines by parts of different types. An FMS can keep a great deal of information on the status of the system, such as information on what is scheduled in the near future, with great accuracy. For example, the knowledge of the time when the next part will arrive at each machine can be neneficial for the routing. This paper tests the effects of the use of this knowledge for part routing on the parts flow time (sum of the time for waiting and service) under a simple routing procedure- a look-ahead routing procedure. A test under many operating conditions shows that the reduction of part flow time from the cases without using this information is between 1% and 11%, which justifies more study on this routing procedure at real production sites when machine capacity is a critical issue. The test results of this paper are also valid for other highly automated systems such as the semi-conductor fabrication plants for routing when the arrivals of parts in the near future are known.

• Steel and Composite Structures
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• v.15 no.1
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• pp.81-101
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• 2013

In this paper a robust 2-noded connection element has been developed for modelling the bolted end-plate connection between steel beam and column at elevated temperatures. The numerical procedure described is based on the model proposed by Huang (2011), incorporating additional developments to more precisely determinate the tension, compression and bending moment capacities of end-plate connection in fire. The proper failure criteria are proposed to calculate the tension capacity for each individual bolt row. In this new model the connection failure due to bending, axial tension, compression and shear are considered. The influence of the axial force of the connected beam on the connection is also taken into account. This new model has the advantages of both the simple and component-based models. In order to validate the model a total of 22 tests are used. It is evident that this new connection model has ability to accurately predict the behaviour of the end-plate connection at elevated temperatures, and can be used to represent the end-plate connections in supporting performance-based fire resistance design of steel-framed composite buildings.

• International Journal of Reliability and Applications
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• v.15 no.2
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• pp.85-98
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• 2014

Accelerated life testing (ALT) is a well famous technique in life testing and reliability studies, this is particularly used to induce so high stress leading to failure of the highly reliable units quickly under stipulated duration of time. The step-stress ALT is one of the systematic experimental strategy of ALT applied to fail the units in steps. In this article we focus on two important issues (i) necessity of life tests at higher steps with relevant causes (ii) to develop a new optimum test plan for 3-step SSALT under the modified cumulative exposure model proposed by Khamis and Higgins (1998). It is assumed that the lifetime of test units follows Rayleigh distribution and its scale parameter at constant stress level is assumed to be a log-linear function of the stress. The maximum likelihood estimates of the parameters involved in the step-stress ALT model are obtained. A simulation study is performed for numerical investigation of the proposed new optimum plan 3-step, step-stress ALT. The necessity of the life test units at 3-step step-stress is also numerically examined in comparison to simple step-stress setup.

• Smart Structures and Systems
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• v.16 no.2
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• pp.263-280
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• 2015

Microwave remote sensing is probably the most recent experimental technique suitable to the non-contact measurement of deflections on large structures, in static or dynamic conditions. In the first part of the paper, the main techniques adopted in microwave remote sensing are described, so that advantages and potential issues of these techniques are presented and discussed. Subsequently, the paper addresses the application of the radar technology to the measurement of the vibration response on the stay cables of two cable-stayed bridges. The dynamic tests were performed in operational conditions (i.e. with the excitation being mainly provided by micro-tremors, wind and traffic) and the maximum deflections of the cables were generally lower than 5.0 mm. The investigation clearly highlights: (a) the safe and simple use of the radar on site and its effectiveness to simultaneously measure the dynamic response of all the stay cables of an array; (b) the negligible effects of the typical issues and uncertainties that might affect the radar measurements; (c) the accuracy of the results provided by the microwave remote sensing in terms of natural frequencies and tension forces of the stay cables; (d) the suitability of microwave interferometry to the repeated application within Structural Health Monitoring programmes.

• Proceedings of KOSOMES biannual meeting
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• 2005.11a
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• pp.71-74
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• 2005

This paper describes Fishery Safety and Security System using F-AIS based on the concepts of RFID(Radio Frequency Identification). This system is to track, protect and arrest the thief who invaded in an fishing ground. The system composed with various functional modules to implement selectively available system providing low cost to high cost and simple function to high function according to user's requirement in a practical fishing fields. Sea trial tests are carried out at Mokpo, Busan and Incheon and, it is found that the system can guard the wide area of cultivating farm field.

• Structural Engineering and Mechanics
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• v.31 no.6
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• pp.697-716
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• 2009

This paper summarizes an experimental and analytical study on the seismic behavior of high strength reinforced concrete columns under cyclic loading. In total six cantilever columns with different sizes and concrete compressive strengths were tested. Three columns, small size, had a $325{\times}325$ mm cross section and the three other columns, medium size, were $520{\times}520$ mm. Concrete compressive strength was 80, 130 and 180 MPa. All specimens were designed in accordance with the Japanese design guidelines. The tests demonstrated that, for specimens made of 180 MPa concrete compressive strength, spalling of cover concrete was very brittle followed by a significant decrease in strength. Curvature was much important for the small size than for the medium size columns. Concrete compressive strength had no effect on the curvature distribution for a drift varying between -2% and +2%. However, it had an effect on the drift corresponding to the peak moment and on the equivalent viscous damping variation. Simple equations are proposed for 1) evaluating the concrete Young's modulus for high strength concrete and for 2) evaluating the moment-drift envelope curves for the medium size columns knowing that of the small size columns. Experimental moment-drift and axial strain-drift histories were well predicted using a fiber model developed by the authors.

• Steel and Composite Structures
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• v.12 no.5
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• pp.379-393
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• 2012

Many steel bridge infrastructures in the world are getting older, and a large number of these structures are in need of maintenance, rehabilitation or replacement. Most of them are subjected to corrosion due to exposure to aggressive environmental conditions and inadequate maintenance, causing reduction of their carrying capacities. In order to have an adequate bridge management, it is of paramount importance to develop an efficient, accurate and rapid condition assessment method which can be used to make reliable decisions affecting the cost and safety. Therefore, a simple and accurate method of calculating remaining yield and tensile strength by using a concept of representative effective thickness with correlation of initial thickness and maximum corroded depth is proposed in this study, based on the results of many tensile coupon tests of corroded plates obtained from a steel plate girder with severe corrosion, used for about 100 years. Furthermore, a strength reduction diagram which will be very useful for bridge inspection engineers to make rational decisions about the maintenance management of aged steel bridge infrastructures is presented.

• Steel and Composite Structures
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• v.12 no.5
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• pp.427-444
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• 2012

This paper presented a new aerial platform-AERORail for rail transport and its structure evolution based on the elastic stiffness of cable; through the analysis on the cable properties when the cable supported a small service load with high-tensile force, summarized the theoretical basis of the AERORail structure and the corresponding simplified analysis model. There were 60 groups of experiments for a single naked cable model under different tensile forces and different services loads, and 48 groups of experiments for the cable with rail combined structure model. The experimental results of deflection characteristics were compared with the theoretical values for these two types of structures under the same conditions. It proved that the results almost met the classical cable theory. The reason is that a small deflection was required when this structure was applied. After the tension increments tests with moving load, it is verified that the relationships between the structure stiffness and tension force and service load are simple. Before further research and applications are made, these results are necessary for the determination of the reasonable and economic tensile force, allowable service load for the special span length for this new platform.