• Steel and Composite Structures
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• v.42 no.1
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• pp.139-149
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• 2022

To simplify the design and reduce the construction cost of traditional multi-girder structural systems, twin I-girder structures are widely used in many countries in recent years. Due to the concern on post-fracture redundancy, however, twin girder bridges are currently classified as fracture critical structures in AASHTO specifications for highway bridges. To investigate the after-fracture behavior of such structures, a composite steel and concrete twin girder specimen was built and an artificial fracture through the web and the bottom flange was created on one main girder. The static loading test was performed to investigate its mechanical performance after a severe fracture occurred on the main girder. Applied load and vertical displacement curves, and the applied load versus strain relationships at key sections were measured. To investigate the load distribution and transfer capacities between two steel girders, the normal strain development on crossbeams was also measured during the loading test. In addition, both shear and normal strains of studs were also measured in the loading test to explore the behavior of shear connectors in such bridges. The functions and structural performance of structural members and possible load transfer paths after main girder fractures in such bridges were also discussed. The test results indicate in this study that a typical twin I-girder can resist a general fracture on one of its two main girders. The presented results can provide references for post-fracture performance and optimization for the design of twin I-girder bridges and similar structures.

• Pediatric Infection and Vaccine
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• v.12 no.2
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• pp.124-134
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• 2005

Purpose : It has been known that the diagnostic confirmation of group A streptococcal pharyngitis is accompanied with the results of throat culture and/or rapid antigen detection test(RADT). This study was designed to evaluate the usefulness and cost benefits of the RADT in patients with a sore throat compared the empirical antibiotic treated group without using RADT or throat culture with the antibiotic treated group according to the results of RADT test and/or throat culture. Methods : From April 2003 to August 2003, total 369 patients were enrolled this study. They were redistributed into two groups. In one group, the RADT test and throat culture were used and the patients received antibiotic treatment according to the results of test and in the other group, no diagnostic examinations were used and the patients were treated with antibiotics which were chosen empirically. The flow sheet with questionnaire was drawing up and obtained the clinical symptoms, signs and the name of antibiotics that were administered. Results : A total of 244 patients were treated after the throat culture and/or RADT, and 125 patients were treated empirically. The prevalence of bacteriologically confirmed group A streptococcal pharyngitis was 20.1%. The sensitivity and specificity of RADT were 89.8% and 86.1%, respectively. Positive predictive value and negative predictive value were 62.0% and 97.1%, respectively. The rate of antibiotic use was high in both groups. Because the physician used the antibiotics even if the result of RADT was negative. So about 37% of reduction of antibiotics use might be possible if we used antibiotics according to the results of RADT. There were no cost differences between the RADT applied group and the empirically treated antibiotic group if we could reduce the price of RADT to 63% of the current price. Conclusion : The RADT could be applied for the easy and rapid diagnosis and prompt treatment for group A streptococcal pharyngitis, and RADT could reduced the number of antibiotics used if the price of RADT was reduced to 63% of current price. For accurate evaluation of efficacy and cost effect, further controlled study is needed.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.05a
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• pp.259-262
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• 2012

The most of military systems that developed today are composed with many sub-systems for mission execution. The test of military systems for delivery test of mass product such that part test, PCB test, component test, integration test. This paper discusses improving productivity test method that functional test of PCB has a various function. Improving productivity is minimize testing item by man and minimize kind of tester, so that decrease product cost by production time for test. PCB tester be developed many kind of test method that systems were developed by many different engineers. This paper study testing check point for testing that how to minimize of kind of tester, how to automatic test for all of function that have inputs and outputs.

• Journal of KIISE:Software and Applications
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• v.41 no.7
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• pp.469-480
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• 2014

Software Product Line (SPL) is a software development paradigm that guarantees high productivity, reduced cost, and shorter time-to-market by systematically planning and reusing commonality and variability. In order to maximize the benefits of SPL engineering, testing should be integrated into the SPL engineering lifecycle processes that consist of domain engineering and application engineering and should be performed with as little test efforts as possible. This paper proposes a systematic software product line test cases derivation method using combinatorial test design. By applying combinatorial test design to product line test cases derivation and exploiting commonality between products at the same time, the number of generated test cases is dramatically reduced with the result that they can be effectively reused by the products of the given product line. Case studies conducted in this paper show the efficacy of our method compared with other methods that use only commonality or combinatorial design or neither of them in terms of the number of derived test cases.

• Fire Science and Engineering
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• v.27 no.5
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• pp.15-18
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• 2013

This paper is concerned with the Performance and Reliability Certification for fire detection system in outdoor area such small and middle sized cultural assets, natural monument and outdoor facilities. Especially, if a fire were to occur in vulnerable area, it is difficulty to detect a fire. therefore we propose a high efficiency and low cost unmanned fire detection system in capable of an early detection regardless spontaneously fire or firebug. for Adoption of Intelligent Fire Detection System with movable and unmanned function breaking from the existing Conventional Fire Detection System, this Range of R&D includes the Performance test, Function test, Field test, Flame Detection test and EMI/EMS Compliance test. the Result data of Performance test, Function test and Field test is generally good during 3 months. also we checked that thermal variation test and EMI/EMS compliance test are good result data within allowable range. As a result of general test, we verified improvement results that the measure distance of fire detection extend 75 m, the Power of waiting time increase 4 hours, the Power of operation time increase 3 days and the context awareness with video as well as sensors.

• International Journal of Naval Architecture and Ocean Engineering
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• v.10 no.4
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• pp.491-498
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• 2018

The cost evaluation for voyage route planning in an ice-covered sea is one of the major topics among ship owners. Information of the ice properties, such as ice type, concentration of ice, ice thickness, strength of ice, and speed-power relation under ice conditions are important for determining the optimal route in ice and low operational cost perspective. To determine achievable speed at any designated pack ice condition, a model test of resistance, self-propulsion, and overload test in ice and ice-free water were carried out in a KRISO ice tank and towing tank. The available net thrust for ice and an estimation of the ice resistance under any pack ice condition were also performed by I-RES. The in-house code called 'I-RES', which is an ice resistance estimation tool that applies an empirical formula, was modified for the pack ice module in this study. Careful observations of underwater videos of the ice model test made it possible to understand the physical phenomena of underneath of the hull bottom surface and determine the coverage of buoyancy. The clearing resistance of ice can be calculated by subtracting the buoyance and open water resistance form the pre-sawn ice resistance. The model test results in pack ice were compared with the calculation results to obtain a correlation factor among the pack ice resistance, ice concentration, and ship speed. The resulting correlation factors were applied to the calculation results to determine the pack ice resistance under any pack ice condition. The pack ice resistance under the arbitrary pack ice condition could be estimated because software I-RES could control all the ice properties. The available net thrust in ice, which is the over thrust that overcomes the pack ice resistance, will change the speed of a ship according to the bollard pull test results and thruster characteristics (engine & propulsion combination). The attainable speed at a certain ice concentration of pack ice was determined using the interpolation method. This paper reports a procedure to determine the attainable speed in pack ice and the sample calculation using the Araon vessel was performed to confirm the entire process. A more detailed description of the determination of the attainable speed is described. The attainable speed in 1.0 m, 90% pack ice and 540 kPa strength was 13.3 knots.

• KIPS Transactions on Software and Data Engineering
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• v.9 no.11
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• pp.357-366
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• 2020

As the proportion and complexity of software embedded in aircraft increase, risk factors such as mission failure, function failure and performance failure due to software errors also increase. In the mission-critical software systems such as aircraft software, managing requirement traceability is essential to maintain the software systems with minimal period and cost. However, the development company is not accurately complying with the guideline for managing requirement traceability due to various reasons such as development cost and schedule. Therefore, it is not easy to systematically establish and maintain requirement traceability. In the paper, we analyze actual test cases of aviation software systems from the viewpoint of requirements traceability in order to learn if there are failure cases of test cases due to the absence of systematic traceability management activities. We also check the risks associated with the failure cases according to the type and severity of the cases. As a result of analyzing a total of 7 aircraft-mounted software, failure cases could be divided into three types: omission of requirements, lack of connection between requirements and test procedures, and omission of test procedures. There were a total of 18 failure cases, 6 for each type. The numbers of high, middle and low risks were 1, 13 and 4, respectively, where the number of middle risks is largest.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.33 no.11
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• pp.106-114
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• 2005

This study addresses space simulation test results and thermal modelling verification of HAUSAT-2 nanosatellite STM (Structural-Thermal Model). The thermal modelling of the HAUSAT-2 has been modified in accordance with test results. Thermal analysis results were repeatedly compared with test results for modified thermal modelling. It is verified that the analysis results for modified thermal modelling agree well with test results. Some surface heaters were implemented to simulate solar illumination for HAUSAT-2 Thermal Vacuum/Balance Test. A low-cost and effective thermal test methodology, which is applicable to ultra-small satellite system, was proposed and verified by test results in this study.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.56-61
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• 2011

The deign and lay-out of a combustion chamber test facility(CTF), a turbopump real propellant test facility(TPTF), a rocket engine test facility for 3rd stage engine(SReTF), a rocket engine ground/high altitude test facility(ReTF, HAReTF) and a propulsion system test complex(PSTC) for KSLV-II is briefly described. The development/qualification tests of engine component, 3rd stage engine system and 75ton-class liquid rocket engine system will be performed in CTF, TPTF, SReTF, ReTF and HAReTF and the development test of 1st/2nd/3rd propulsion systems for KSLV-II will be performed in PSTC. These propulsion test facilities will be built in NARO space center considering construction schedule, cost, safety distance and utility factor of propulsion test facilities.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.05a
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• pp.326-331
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• 2006

The durability of recent motors is longer than the past one because there are the rapid technique development of the automobile industry and the vehicle maintenance of users. And then the importance of the durability test due to vibration is increased from day to day. So full vehicle and parts companies accomplish the durability test using various methods. The most public test method among them is the reliable field test but it bring on higher cost and period of the development process. The durability test using MAST(multi axis simulation table) is a solution in order to improve the development process of automobiles. Generally its excitation source uses the optimized road profiles that are obtained by the road test of belgian road, country road, cobbleston road and so on instead of a real field but the interrelations and influences accordingly vehicle damage are considered by a field test between specific roads and real fields in the first place. Therefore this study, in order to accomplish a basic research for the durability test using the MAST, performed on the real field driving test at various domestic roads and the results which are analyzed by PSD(power spectrum density) are compared with relative sensitivity among the roads. Consequently they can present a basic material for generation of road profiles which is applied to the durability test using MAST.