• 한국암반공학회:학술대회논문집
• /
• 한국암반공학회 2011년도 추계 총회 및 창립 30주년 기념 심포지엄
• /
• pp.3-21
• /
• 2011

Laboratory experiments and numerical simulations using Particle Flow Code (PFC2D) were performed to study the effects of joint separation and joint overlapping on the full failure behavior of rock bridges under direct shear loading. Through numerical direct shear tests, the failure process is visually observed and the failure patterns are achieved with reasonable conformity with the experimental results. The simulation results clearly showed that cracks developed during the test were predominantly tension cracks. It was deduced that the failure pattern was mostly influenced by both of the joint separation and joint overlapping while the shear strength is closely related to the failure pattern and its failure mechanism. The studies revealed that shear strength of rock bridges are increased with increasing in the joint separation. Also, it was observed that for a fixed cross sectional area of rock bridges, shear strength of overlapped joints are less than the shear strength of non-overlapped joints.

• 문화기술의 융합
• /
• 제6권4호
• /
• pp.685-692
• /
• 2020

본 연구에서는 철근 겹침이음 위치가 부적정하게 시공된 사례를 바탕으로 콘크리트 구조기준에서 제시한 설치기준에 대하여 분석 및 고찰을 하였으며, 현행 구조기준에서 제시한 겹침이음에 대한 기준이 적정함을 해석적으로 입증하였다. 실제 종방향 균열이 발생된 지하 박스구조물 단면에 대한 철근 겹침이음부의 철근강도감소비 및 설계유효 모멘트를 산출하여 철근 겹침이음부의 균열 발생원인에 대하여 해석적으로 입증하였다. 연구결과, 최대 인장응력이 발생되는 지하 박스구조물 중앙부에 철근 겹침이음이 설치될 경우 철근 겹침이음부의 철근강도감소비는 82.8% 수준인 것으로 분석되었다. 따라서, 콘크리트 구조기준에서 정하고 있는 바와 같이 철근 겹침이음부의 위치는 최대 인장응력이 발생하는 지점을 피해야 하며, 부득이하게 겹침이음이 부적정한 위치에 설치되는 경우 본 연구에서 검토한 바와 같이 충분한 겹침이음길이를 확보하여야 하며, 구조물 단면력에 대하여 검토하여 충분한 안전율을 확보하는 것이 중장기적인 균열 제어 방법으로 적정할 것으로 검토되었다.

• 대한토목학회논문집
• /
• 제28권4A호
• /
• pp.581-590
• /
• 2008

프리캐스트 패널은 교량바닥판의 합성 구조부재로서 사용된다. 프리캐스트 패널의 횡방향 철근은 교량바닥판의 주철근 역할을 하며, 또한 패널 상부의 현장타설 콘크리트 시공시 거푸집 대용으로도 적용된다. 이 논문에서 3가지 이음부 형상을 적용한 합성보 시험체에 대해서 정적실험을 수행하여 강도 및 균열폭을 검토하였다. 실험결과, 루프이음을 적용한 반단면 프리캐스트 부재의 연속성이 우수함을 확인하였고, 루프이음의 겹이음 길이와 횡방향 보강철근의 영향도 검토하였다. 루프이음의 겹이음 길이가 증가할수록 루프이음 반단면 프리캐스트 부재의 휨강도가 증가하였다. 또한, 루프이음부에 횡방향 보강철근은 균열제어에 매우 효율적임을 확인하였다.

• 한국CDE학회논문집
• /
• 제12권2호
• /
• pp.95-100
• /
• 2007

Virtual Reality(VR) data in VR environments like Manufacturing industries are often created jointly by many creators. It is then necessary to provide protection of the joint-creatorship and the creatorship of each participating creator. This paper proposes Multiple Digital Watermarking Framework(MDWF) to solve the problem of joint-creatorship. The proposed framework, MDWF, makes use of 3D private watermarking technology and a novel key sharing protocol for joint-creatorship verification. MDWF embeds 3D private multiple watermarks for the creatorship of each participating creators in a non-overlapping manner during the creation process. After key agreement of all private keys, MDWF embeds an additional 3D private watermark for the joint-creatorship. Therefore MDWF successfully handles the creatorship dispute among creators. That is, each participation creator can prove his/her partial creatorship as well as joint-creatorship by MDWF. In addition, MDWF can solve the collusion problems because shared secret key(SSK) can be made by every users.

• 한국건축시공학회:학술대회논문집
• /
• 한국건축시공학회 2018년도 추계 학술논문 발표대회
• /
• pp.147-148
• /
• 2018

Seat waterproofing materials applied to the roof of a building concrete structure inevitably produce joints and are applied with opposite dam joints or overlapping joints depending on the waterproof material applied to the top of the sheet. In this case, the joint performance is determined by the material at the top, rather than by the superimposed joint. In order to solve this problem, various reinforcements have been used to apply to the connecting parts of the opposite dam, but the problem of attachment between different materials or the lack of reinforcement of the joint tape has not been solved. Therefore, for the purpose of securing tensile performance to the joints, this study is used as a reinforcement for the joints of PP materials with high tensile performance and as a reinforcement for nylon materials.

• 전자공학회논문지S
• /
• 제34S권2호
• /
• pp.94-103
• /
• 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.

• 치과방사선
• /
• 제3권1호
• /
• pp.19-28
• /
• 1973

The author has studied maxillo-facial anatomical landmarks using Status X with two methods. The one has performed by application of contrast media on the human dry skull, the other has performed on living human skull as control group. Comparing the panagraphs taken by two methods, the author has drawn following results: 1. The panagraphs revealed the undistorted, highly sharp panoramic shadows of each jaw on a film. 2. Diminishing the inserted anode tube overlapping-free representation of the anterior teeth was taken. 3. Alternating the head position of the objects, direction of anode tube and film placing, the shadows of temporo-mandibular joint and zygomatic arch were taken without overlapping the other bone tissues. 4. In the panagraphs applied various shaped contrast media to each anatomical landmark, a radio-anatomical atlas which is necessary to interpret various bone tissues was taken. 5. In order to interpret panagraphic shadows easily, the author has tried this study by comparing the films of the living human skull with the films of the human dry skull applied contrast media.

• Animal Systematics, Evolution and Diversity
• /
• nspc9호
• /
• pp.30-36
• /
• 2016

As a part of the commemorative joint faunal survey for the 30th anniversary of the Korean Society of Systematic Zoology, the molluscan fauna of Jindo Island was investigated based on sample collection from 6 localities from the 6 to the 8 of Jul 2016. A total of 114 molluscan species from 47 families were collected and identified. Among these, 42 species from 11 families are newly reported from Jindo Island and combining the previous records with the present study totals 157 species from 57 families. Distribution of species records indicates that marine biogeography of Jindo Island represent an overlapping zone for marine organisms which dwell in the Yellow sea and the southern sea areas of Korean waters.

• Steel and Composite Structures
• /
• 제42권2호
• /
• pp.173-190
• /
• 2022

With the development of spatial structures, the joints are becoming more and more complex to connect tubular members of spatial structures. In this study, an approach is proposed to establish high-efficiency finite element model of multiplanar KTX-joint with the weld geometries accurately simulated. Ultimate bearing capacity the KTX-joint is determined by the criterion of deformation limit and failure mechanism of chord wall buckling is studied. Size effect of fillet weld on the joint ultimate bearing capacity is preliminarily investigated. Based on the validated finite element model, a parametric study is performed to investigate the effects of geometric and loading parameters of KT-plane brace members on ultimate bearing capacity of the KTX-joint. The effect mechanism is revealed and several design suggestions are proposed. Several simple reinforcement methods are adopted to constrain the chord wall buckling. It is concluded that the finite element model established by proposed approach is capable of simulating static behaviors of multiplanar KTX-joint; chord wall buckling with large indentation is the typical failure mode of multiplanar KTX-joint, which also increases chord wall displacements in the axis directions of brace members in orthogonal plane; ultimate bearing capacity of the KTX-joint increases approximately linearly with the increase of fillet weld size within the allowed range; the effect mechanism of geometric and loading parameters are revealed by the assumption of restraint region and interaction between adjacent KT-plane brace members; relatively large diameter ratio, small overlapping ratio and small included angle are suggested for the KTX-joint to achieve larger ultimate bearing capacity; the adopted simple reinforcement methods can effectively constrain the chord wall buckling with the design of KTX-joint converted into design of uniplanar KT-joint.

• Smart Structures and Systems
• /
• 제22권4호
• /
• pp.459-468
• /
• 2018

In this paper, the effect of non-persistent joints was determined on the behavior of concrete specimens subjected to biaxial loading through numerical modeling using particle flow code in two dimensions (PFC2D). Firstly, a numerical model was calibrated by uniaxial, Brazilian and triaxial experimental results to ensure the conformity of the simulated numerical model's response. Secondly, sixteen rectangular models with dimension of 100 mm by 100 mm were developed. Each model contains two non-persistent joints with lengths of 40 mm and 20 mm, respectively. The angularity of the larger joint changes from $30^{\circ}$ to $90^{\circ}$. In each configuration, the small joint angularity changes from $0^{\circ}$ to $90^{\circ}$ in $30^{\circ}$ increments. All of the models were under confining stress of 1 MPa. By using of the biaxial test configuration, the failure process was visually observed. Discrete element simulations demonstrated that macro shear fractures in models are because of microscopic tensile breakage of a large number of bonded discs. The failure pattern in Rock Bridge is mostly affected by joint overlapping whereas the biaxial strength is closely related to the failure pattern.