• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.10a
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• pp.127-128
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• 2006

• Tunnel and Underground Space
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• v.19 no.1
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• pp.1-10
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• 2009

Site characterization for structural stability in rock masses mainly involves the collection of joint property data, and in the current practice, much of this data is collected by hand directly at exposed slopes and outcrops. There are many issues with the collection of this data in the field, including issues of safety, slope access, field time, lack of data quantity, reusability of data and human bias. It is shown that information on joint orientation, spacing and roughness in rock masses, can be automatically extracted from LIDAR (light detection and ranging) point floods using the currently available Split-FX point cloud processing software, thereby reducing processing time, safety and human bias issues.

• Steel and Composite Structures
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• v.6 no.1
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• pp.33-53
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• 2006

The rotational behaviour of bolted extended end plate beam-to-column connections is evaluated in the context of the component method. The full moment-rotation response is characterized from the force-deformation curve of the individual joint components. The deformability of end plate connections is mostly governed by the bending of the column flange and/or end plate and tension elongation of the bolts. These components form the tension zone of the joint that can be modelled by means of "equivalent T-stubs". A systematic analytical procedure for characterization of the monotonic force-deformation behaviour of individual T-stub connections is proposed. In the framework of the component method, the T-stub is then inserted in the joint spring model to generate the moment-rotation response of the joint. The procedures are validated with the results from an experimental investigation of eight statically loaded extended end plate bolted moment connections carried out at the Delft University of Technology. Because ductility is such an important property in terms of joint performance, particularly in the partial strength joint scenario, special attention is given to this issue.

• Journal of the Korean Society of Safety
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• v.18 no.3
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• pp.69-74
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• 2003

To investigate the partial discharge and electric field distribution in cable joint parts, we measured the partial discharge and electric field in specimen. The specimens which cross-linked polyethylene(XLPE) and ethylene propylene diene ethylene(EPDM) are used to insulating material for underground cable md cable jointing parts. The polymers are used to insulating material in switchgear which is a kind of transformer equipment and in ultra-high voltage cable. Its using is increasing gradually, the electrical insulation properties are not only excellent but also mechanical property is excellent. And because it is possible to be made void of several type in insulator while it is produced, which the electrical field distribution is changed by void, it has a critical influence to insulator performance. The underground cable is connecting by the jointing material, insulating breakdown and the electric ageing which are caused by several mixing impurity and the damage of cable insulator layer, which reduced the life of cable while intermediate joint kit is connected. Therefore, the computer simulation is used to estimating insulator performance, XLPE is used to the insulating material of ultra-high voltage cable and EPDM is used to insulator layer in joint material kit, and which are produced as specimen. And it is analyzed the electric field concentrating distribution and partial discharge by modeling of computer simulation in void and cable joint kit.

• Journal of the Korean Wood Science and Technology
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• v.16 no.4
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• pp.48-53
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• 1988

This study was carried out to investigate the effects of pressing time and spreading amount, moisture content, gap-distance with butt to butt joint and adhesives on bonding strength in manufacturing the laminated wood with Pitch pine (Pinus rigida). The results obtained were as follows: 1) The pressing time of 12 hours, 10 kilogram per square centimeter of pressure and 200 gram per square meter of spreading amount were required to reach over 50 kilogram per square centimeter (block shear strength) in manufacturing the laminated wood by aqueous vinyl urethane adhesive. 2) The bonding strength decreased with the increase of moisture content of wood. The block shear strength, however, showed over 100 kilogram per square centimeter when the strength test was carried out after air-drying the laminated wood in high moisture content (30-70%). 3) Regardless of direction of load, every flexural property decreased with the increase of gap-distance with butt to butt joint. However, little of every flexural property was changed at 0.5 millimeter of joint-gap distance. The flexural property of vertically laminated wood (perpendicular to glue line to load direction: 1) showed more than that of horizontally laminated wood (parallel to glue line to load direction: //). 4) Among five adhesives used at this experiment, the bonding strength of aqueous vinyl urethane adhesive was the highest in dry bond and wet tests.

• Journal of Electrical Engineering and Technology
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• v.9 no.6
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• pp.2114-2117
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• 2014

Joint pain is generally a common disorder not only for the old aged people but also for the immunocompromised patients. The present proposed study reveals the presence of inflammatory diseases in joint generally diagnosed by removing synovial fluid and changes in the volume and composition are examined for the presence of WBC and crystals. This study implement a non-invasive approach to identify the changes in joint fluid by measuring the changes in electrical property of the synovial tissue under the influence of electrical current signal with frequency range between 100 kHz to 300 kHz. The response of tissue for the current signal was measured in terms of potential drop across the tissue. The hardware system design consists of input and output sections. The input section which applies current signal to upper limb joint region is made of ICL8038 function generator IC with amplifier and voltage to current converter. The output section picks voltage variation using metal surface electrode, amplifier, ADC, PIC microcontroller and LCD interface. 100 patient inclusive of normal and disease affected patients where examined for upper limb synovial fluid variation and inflammatory diseases were identified.

• Transactions of the Korean Society of Mechanical Engineers
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• v.19 no.7
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• pp.1651-1656
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• 1995

The adhesively bonded tubular single lap joint shows large nonlinear behavior in the loaddisplacement relation, because structural adhesives for the joint are usually rubber toughened, which endows adhesives with nonlinear shear properties. since the majority of load transfer of the adhesively bonded tubular single lap joint is accomplished by the nonlinear behavior of the adhesive, its torque transmission capability should be calculated incorporating nonlinear shear properties. However, both the analytic and numerical analyses become complicated if the nonlinear shear properties of the adhesive are included during the calculation of torque transmission capabilities. In this paper, in order to obtain the torque transmission capabilities easily, an iterative solution which includes the nonlinear shear properties of the adhesive was derived using the analytic solution with the linear shear properties of the adhesive. Since the iterative solution can be obtained very fast due to its simplicity, it has been found that it can be used in the design of the adhesively bonded tubular single lap joint.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.8
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• pp.1388-1397
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• 2003

Since the reliability of adhesively bonded joints for composite structures is dependent on many parameters such as the shape and dimensions of joints, type of applied load, and environment, so an accurate estimation of the fatigue life of adhesively bonded joints is seldom possible, which necessitates an in-situ reliability monitoring of the joints during the operation of structures. In this study, a self-sensor method for adhesively bonded joints was devised, in which the adhesive used works as a piezoelectric material to send changing signals depending on the integrity of the joint. From the investigation, it was found that the electric charge increased gradually as cracks initiated and propagated in the adhesive layer, and had its maximum value when the adhesively bonded joint failed. So it is feasible to monitor the integrity of the joint during its lifetime. Finally, a relationship between the piezoelectric property of the adhesive and crack propagation was obtained from the experimental results.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.34S no.2
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• pp.94-103
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• 1997

The WCHF-FSJTC (wavelet circular harmonic function frequency selective joint transform correlator) using th wavelet transformed CHF as the reference image in FSJTC is proposed for rotation invariant pattern recognition. Since the wavelet transform has the property of feature extraction, the proposed system can have the better DC (discrimination cpability) and the higher SNR(signal to noise ratio) compared with the conventional CHF-CJTC(circular harmonic function conventional joint transform correlator). And since the structure of the proposed system is FSJTC which can eliminate auto-correlation and cross-correlation between input images, it can eliminate false alarm caused by the overlapping among correlation peaks. The used wavelet functio is the morlet function, which is proper for the reference image used in this paper. the optimal dialation parameter and oscillation frequency of the wavelet function are also achieved with varying the parameters of the wavelet function. The computer simulation shows that the proposed system has the best performance when the dilation parameter is 0.8 and the oscillation frequency is 0.48.

• Journal of Mechanical Science and Technology
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• v.16 no.12
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• pp.1627-1632
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• 2002

In this paper, a simplified ultrasonic CT system, which uses the information in three directions, that is, 90°, ＋45° and －45°about the inspection plane, is applied to the high strength steel, and the frequency analysis method for enhancing the C scan or CT image is developed. This frequency analysis method is based on the frequency response property of the material. By comparing the magnitudes in the frequency domain, the special frequency which shows a significant difference between the welded joint and base material was found and used to obtain a C scan or CT image. Experimental results for several kinds of specimens, having a welded joint by electron beam welding, a weld joint by arc welding, on a fatigue crack, showed that the obtained C scan or CT image has better resolution than the results of previous experiments using the maximum value of the received waveform.