• Journal of Korean Society of Steel Construction
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• v.25 no.3
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• pp.255-265
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• 2013

The major goal of this study is to develop the industrialized structural system that can build high-rise buildings using the box-shaped steel frames such as a unit module system. In order to achieve such a goal, we need the advanced details for joints that consist in a single unit. Furthermore we also need to commercialize the unit modular building system through the basic experiments, research of theoretical analysis and the achievement of seismic performance. This study derived to develop the derails in the beam-to-column joint and to carry out structural performance test. Test results, a joint with thickness of 6.0T can be possible to maintain the plastic rotational angle for strength and seismic performance. Therefore, joint with thickness of 6.0T is able to apply when considering reinforcement in the local of stress concentration.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.10
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• pp.1261-1267
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• 2013

In multibody mechanical systems, low-degree-of-freedom (DOF) joints such as revolute and translational joints are much more frequently used than high-DOF joints. In order to formulate kinematic constraint equations, especially for low-DOF joints, in an efficient and systematic manner, this paper presents a parametric generalized coordinate formulation as a new approach for describing constraint equations. In the proposed approach, joint constraint equations are formulated in terms of a mixed set of Cartesian and parametric generalized coordinates, which drastically reduces the complexity and computational cost of the partial derivatives of the constraints such as the constraint Jacobian. The proposed formulation is validated using a simple cylinder-crank system with an implicit integrator.

• Journal of the Korea institute for structural maintenance and inspection
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• v.9 no.1
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• pp.197-204
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• 2005

Multipurpose Floor Level Joint(MFLJ) is a new construction technology system which was developed in domestic. By using this system, it is possible not only to absorb the deformation at expansion joint due to shrinkages of concrete but also to make ease the floor leveling during the concrete casting at floor. The system consists of two elements, supporting devices and rails. Their structural capacities were verified through several experimental programs, such as compressive strength test of support and bending test of rail. The purpose of this paper is to evaluate the deformation absorbing capacity of the floor level joint. An experimental work was carried out to simulate the deformation condition at the joint and the test result was analyzed and evaluated. In addition, FEM analysis for expansion joint of typical building was also performed to predict the real behavior of MFLJ. The test results showed that MFLJ has sufficient deformation capacity required to act as expansion joint.

• The Journal of the Korea institute of electronic communication sciences
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• v.14 no.1
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• pp.41-48
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• 2019

This paper deals with the design of the L-band rotary joint, which is a core part of the tracking radar system. The rotary joint is a part that is mounted on the rotating parts of the tracking system antenna, which smoothly transmits RF signals with minimizing signal insertion loss. To improve the insertion loss of rotary joint, 1) dielectric materials, 2) design of distribution ring and 3)dielectric shape are studied. The performance of proposed rotary joint is compared with the conventional product. The prototype rotary joint showed a max insertion loss of 0.68dB, that is improved about 46% compare with conventional product which insertion loss was 1.26dB.

• Composites Research
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• v.19 no.4
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• pp.15-22
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• 2006

One of the primary factors limiting the application of composite-metal adhesively bonded joints in structural design is the lack of a good evaluation tool for the interfacial strength to predict the load bearing capacity of boned joints. In this paper composite-steel adhesion strength is evaluated in terms of stress intensity factor and fracture toughness of the interface corner. The load bearing capacity of double lap joints, fabricated by co-cured bonding of composite-steel adherends has been determined using fracture mechanical analysis. Bi-material interface comer stress singularity and its order are presented. Finally stress intensities and fracture toughness of the wedge shape bi-material interface corner are determined. Double lap joint failure locus and its mixed mode crack propagation criterion on $K_1-K_{11}$ plane have been developed by tension tests with different bond lengths.

• Composites Research
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• v.16 no.4
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• pp.51-58
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• 2003

Since the reliability of adhesively bonded joints is much dependent on the curing status of thermosetting adhesive, the on-line cure monitoring during the cure of adhesively joints could improve the quality of adhesively bonded joints. In this work, the dielectric method which measures the dissipation factor of the adhesive during the cure of joints and converts it into the degree of cure of the adhesive was devised. The relation between the dissipation factor and the degree of cure of adhesive was investigated, which could eliminate the temperature effect on the dissipation factor that is a strong function of the degree of cure and temperature of adhesive. From the investigation, it was found that the dissipation factor showed a trend similar to the cure rate of the adhesive.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2005.05a
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• pp.933-937
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• 2005

FCBGA가 마더보드에 실장된 후 솔더 조인트에 균열이 생기면 단선이 발생한다. 솔더 조인트의 신뢰성을 평가하기 위한 방법 중 전단강도시험(shear test)은 약한 솔더 조인트를 판별하기 어려워 양품 로트와 불량 로트를 구별할 수 없으며, 인장강도시험(pull test)은 솔더 볼의 위치별 산포가 크고, peel test는 품질을 정량적으로 나타낼 수 없는 등의 문제가 있다. 새로운 시험 방법은 Area Pull Test(이하 APT)라 명명했으며 peel test와 pull test를 합한 개념으로서, 시험 샘플을 만드는 과정은 peel test와 동일하다. 솔더 조인트의 인장강도 측정은 지그를 만들어서 FCBGA 전체를 당겨서 측정하였다. 샘플은 Ni도금 두께를 3, 5, 8 ${\mu}m$로 제작하여 불량(3${\mu}m$), 양품으로 구분하였고, 양품 또한 품질 수준을 두가지(5,8${\mu}m$)로 나누었다. 그 결과 peel test 기준에 의거한 불량, 양품을 정량적인 수치(인장강도)로 판별할 수 있었으며, 솔더 조인트의 파괴모드별 인장강도를 구분 할 수 있었다.

• Journal of the Korea Concrete Institute
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• v.27 no.4
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• pp.435-441
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• 2015

Concrete, as a porous media, has permeability and it is considered as a major parameter for durability evaluation. Cold joint caused by delayed placing of concrete accelerates water permeation and intrusion of harmful ions. In the paper, concrete specimens containing GGBFS (Ground Granulated Blast Furnace Slag) and OPC (Ordinary Portland Cement) are prepared with cold joint section, and water permeability and water flow at the age of 91 days are measured for 2 weeks. Sound concrete with GGBFS shows decreased permeability to 89% for sound concrete with OPC and 0.86 of decreasing ratio is evaluated in GGBFS concrete with cold joint. Through WPT (Water Penetration Test), the effects of mineral admixture and cold joint on water permeability are evaluated, and variation in water behavior via cold joint is analyzed through probabilistic method as well.

• The Journal of the Korea Contents Association
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• v.11 no.4
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• pp.215-224
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• 2011

There have been studying many researches to detect human body and to track one with increasing interest on human and computer interaction. In this paper, we propose the algorithm that automatically extracts joints, linked points of human body, using the ratio of human body under single camera and tracks object. The proposed method gets the difference images of the grayscale images and ones of the hue images between input image and background image. Then the proposed method composes the results, splits background and foreground, and extracts objects. Also we standardize the ratio of human body using face' length and the measurement of human body and automatically extract joints of the object using the ratio and the corner points of the silhouette of object. After then, we tract the joints' movement using block-matching algorithm. The proposed method is applied to test video to be acquired through a camera and the result shows that the proposed method automatically extracts joints and effectively tracks the detected joints.

• Composites Research
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• v.18 no.1
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• pp.1-9
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• 2005

A methodology is presented for the failure prediction of composite single-lap bonded joints considering both of composite adherend failure and bondline failure. An elastic-perfectly plastic model of adhesive and a delamination failure criterion are used in the methodology. The failure predictions have been performed using finite element method and the proposed methodology. The failure prediction results such as failure mode and strength have very good agreements with the test results of joint specimens with various bonding methods and parameters. The influence of variations in the effective strength (that is, adhesion performance) and plastic behavior of adhesive on the failure characteristics of composite bonded Joints are investigated numerically. The numerical results show that optimal joint strength is archived when adhesive and delamination failure occur in the same time.