• 한국도로학회:학술대회논문집
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• 2002.10a
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• pp.283-286
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• 2002

• Proceedings of the IEEK Conference
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• 1999.06a
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• pp.841-844
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• 1999

VDSL noises should be used for testing and evaluation of VDSL systems. In DMT systems for ADSL, noises are generated using IIR filters obtained from the Yule-Walker equations. However, this method cannot be directly applied to VDSL environments. In this paper, an DCT-based VDSL noise generation algorithm is proposed.

• Journal of Broadcast Engineering
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• v.2 no.1
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• pp.24-35
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• 1997

Basic and transmission video quality testing was performed in real-time mode using hardware video codec based on MPEG-2 MP@ML standard including subsequent transmitting and receiving satellite simulator unit. The double-stimulus Impairment scale method and the double-stimulus continous quality scale method based on CCIR 500-5 were used as an evaluation method. The whole digital broadcasting satellite system consisting of MPEG-2 codec, system mux/demux, channel codec, channel, modem, antenna, etc. was put into the overall video quality testbed and the basic and transmission error quality assessment was performed at various bitrates and BER for an integrated system performance evaluation. In transmission error video quality testing, transmission error video quality maintained on average above 3.9 point on the 5-point scale. The low-bit rate quality such as film mode(@2Mbps) highly depended on the statitical characteristics of video source and maintained on average around 2.7 point.

• Journal of Adhesion and Interface
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• v.5 no.2
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• pp.22-36
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• 2004

Several in-situ testing methods of adhesively bonded joints under static short-time tensile loading are critically analyzed in terms of experimental procedure and data evaluation. Due to its rather homogeneous stress state across the glue line, the tensile-shear test with thick single-lap specimens, according to ISO 11003-2, has become the most important test process for the determination of realistic materials parameters. This basic method, which was improved in both, the experimental part by stepped adherends and easily attachable extensometers and the evaluation procedure by numeric substrate deformation correction and test simulation based on the finite element method (FEM), is therefore demonstrated by application to several kinds of adhesives and metallic adherends. Multi-axial load decreases the strength of a joint. This effect, which is illustrated by an experimental comparison, impedes the derivation of realistic mechanical characteristics from measured force-displacement curves. It is shown by numeric modeling that tensile-shear tests with thin plate substrates according to ISO 4587, which are widely used for quick industrial quality assurance, reveal an inhomogeneous stress state, especially because of relatively large adherend deformation. Complete experimental determination of the elastic properties of bonded joints requires independent measurement of at least two characteristics. As the thick-adherend tensile-shear test directly yields the shear modulus, the tensile butt-joint test according to ISO 6922 represents the most obvious complement of the test programme. Thus, validity of analytical correction formulae proposed in literature for the derivation of realistic materials characteristics is verified by numeric simulation. Moreover, the influence of the substrate deformation is examined and a FEM correction method introduced.

• Archives of design research
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• v.12 no.3
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• pp.105-114
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• 1999

As the microelectronics technology is developed, new types of smart intelligent products are being emerged. OSD user interface is one of the critical factor in this kind of product, especially brown goods and information devices, as it is responsible for imput and output function. OSD is being treated as accompaniment to hardware in spite of its importance, and therefore is developed from only simple and separate usability testing based on performance measurement. This study propose a usability evaluation method of OSD based on subjective preference to support existing usability testing. The purpose of this analysis is to make clear what is important factor and how its preference level is from the user's viewpoint. The various attributes of OSD are clarified from user's questionaire and interview, and orthogonal array is generated with specified factor levels. The prototypes are generated from rapid prototyping tool and tested in natural simulation environment. The preference data which collected in this usability testing is analyzed with conjoint analysis module. This usability evaluation is not the final stage in user interface design process but the early planned and circulated stage.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• autumn
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• pp.405-410
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• 2002

Earned Value Management System(EVMS) has been institutionalized as an advanced management technique of construction project lately. And its research has been in the active progress in order to utilize the earned value concept as a project management tool for construction project ordered by both government and private sector. However it is necessary to test and prove the EVMS's adaptability to our construction environment by EVMS's several of operations before its introduction. Project forecasting phase of EVMS is the Estimate at Completion by utilizing earned value data. So, the purpose of this study is to propose EAC evaluation method for evaluation the accuracy of the EAC and encouraging cost realism, and to test for proving the validity of the evaluation methods through hypothesis testing.

• Particle and aerosol research
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• v.18 no.4
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• pp.137-145
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• 2022

As many studies on the harmfulness of fine dust have been reported, awareness of its seriousness is spreading. Recently, interest in indoor air quality as well as air pollution is increasing, and research on measures to block fine dust flowing into the room from the outside is being conducted. The clothing company is launching functional clothing to prevent fine dust attached to clothing from entering the room through outdoor activities. However, it is difficult to confirm whether there is actually fine-dust blocking performance, and there is no evaluation standard. In this study, the contamination rate caused by fine dust was quantitatively compared through image processing after contamination of the outer fabric for 4 types of commercially available functional clothing with fine-dust blocking effect. The difference in particle contamination according to the material of the outer fabric was analyzed by comparing the surface resistance, and it was found that the higher the surface resistance of the outer fabric material, the more fine dust was attached. The analysis method of this study is expected to be able to quantitatively compare and evaluate the fine-dust blocking performance of functional clothing.

• Tribology and Lubricants
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• v.13 no.2
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• pp.8-15
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• 1997

It is very difficult to express the state of a tested engine objectively concerning the malfunction, failure and wear of an engine. The general method of engine evaluation is to express evaluator's opinion for the engine state after testing. However, these methods is only subjective evaluation because test engineers, designers, and evaluators does not easily coincide in opinion. Therefore, in this article, the method of engine rating are introduced in order to represent the qualitative trends into quantitative value. The purpose of Engine Rating is to assign a quantified value to the tribology state of a tested engines. Originally, this Engine Rating method have been used to evaluate the performance of engine oil quantitavely. Using this method, we can predict the proper interval of engine oil change due to its objectivity. So, we can prevent the frequent change of engine oil and protect the environmental contamination. Furthermore, this method can be used to tell the general state of a tested engine after finishing engine durability tests. A single merit scale is used to evaluate numerically the state of cleanliness and the mechanical condition. Generally, a part which is absolutely clean or shows no wear, is rated merit 10. A part which is absolutely dirty or very worn, is rated merit 0.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1990.04a
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• pp.171-185
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• 1990

In order to measure the shape deformation of seat surfaces, an indentation measurement mat was devised. The 50cm * 50 cm mat containing small polyethylene beads were made using two sheets of polyurethane film. The indentation measurement mat was shaped by vacuuming between the subject and the testing seat. This method showed less than 5mm of deformation measurement error. Deformation of CADILLAC and MAXIMA seats were compared to demonstrate usefulness of the new method.

• Smart Structures and Systems
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• v.14 no.6
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• pp.1269-1289
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• 2014

With the sub-stepping technique, the numerical analysis in real-time dynamic hybrid testing is split into the response analysis and signal generation tasks. Two target computers that operate in real-time may be assigned to implement these two tasks, respectively, for fully extending the simulation scale of the numerical substructure. In this case, the integration time-step of solving the dynamic response of the numerical substructure can be dozens of times bigger than the sampling time-step of the controller. The time delay between the real and desired feedback forces becomes more striking, which challenges the well-developed delay compensation methods in real-time dynamic hybrid testing. This paper focuses on displacement prediction and force correction for delay compensation in the real-time dynamic hybrid testing with a large integration time-step. A new displacement prediction scheme is proposed based on recently-developed explicit integration algorithms and compared with several commonly-used prediction procedures. The evaluation of its prediction accuracy is carried out theoretically, numerically and experimentally. Results indicate that the accuracy and effectiveness of the proposed prediction method are of significance.