An Evaluation Method for Three-Dimensional Morphologies of Discontinuities considering the Shear Direction

Qingzhao Zhang,Qing Pan,장보안 대한지질공학회 2022 지질공학 Vol.32 No.1

Rock discontinuities, as weak interfaces in rock, control mechanical properties of rock mass. Presence of discontinuities complicates the engineering properties of rock, which is the root of anisotropy and heterogeneity that have nonnegligible influences on the rock engineering. Morphological characteristics of discontinuities in natural rock are an important factor influencing the mechanical properties, particularly roughness, of discontinuities. Therefore, the accurate measurement and characterization of morphologies of discontinuities are preconditions for studying mechanical properties of discontinuities. Taking discontinuities in red sandstone as research objects, the research obtained three-dimensional (3D) morphologies of discontinuities in natural rock by carrying out 3D morphological scanning tests. The waviness and roughness were separated from 3D morphologies of rock discontinuities through wavelet transform. In addition, the calculation method for the overall slope root mean square (RMS) as well as slope RMSs of waviness and roughness of 3D morphologies of discontinuities considering the shear direction was proposed. The research finally determined an evaluation method for 3D morphologies of discontinuities by quantitatively characterizing 3D morphologies with the mean value of the three slope RMSs.

Numerical investigation of the impact of geological discontinuities on the propagation of ground vibrations

Haghnejad, Ali,Ahangari, Kaveh,Moarefvand, Parviz,Goshtasbi, Kamran Techno-Press 2018 Geomechanics & engineering Vol.14 No.6

Blast-induced ground vibrations by a significant amount of explosives may cause many problems for mining slope stability. Geological discontinuities have a significant influence on the transmission of dynamic pressure of detonation and according to their position relative to the slope face may have damaging or useful impacts on the slope stability. In this study, the effect of geological discontinuities was investigated by modelling a slope with geological discontinuities through applying the dynamic pressure in three-dimensional discrete element code (3DEC). The geological discontinuities in four states that generally apperceived in mine slopes are considered. Given the advantages of the pressure decay function defined by some researcher, this type of function was used to develop the pressure-time profile. The peak particle velocities (PPV) values were monitored along an axis by utilization of Fish programming language and the results were used as an indicator to measure the effects. As shown in the discontinuity-free model, PPV empirical models are reliable in rocks lacking discontinuities or tightly jointed rock masses. According to the other results, the empirical models cannot be used for the case where the rock mass contains discontinuities with any direction or dip. With regard to PPVs, when the direction of discontinuities is opposite to that of the slope face, the dynamic pressure of detonation is significantly damped toward the slope direction at the surface of discontinuities. On the other hand, when the discontinuities are horizontal, the dynamic pressure of detonation affects the rock mass to a large distance.

불연속적 산업진화의 동태적 접근에 관한 탐색적 연구

조동성(Dong Sung Cho),이윤철(Yun Cheol Lee),박재찬(Jae Chan Park),한성수(Sung Soo Han) 한국경영학회 2004 Korea Business Review Vol.8 No.1

산업진화는 시간의 흐름에 따른 산업의 동태적인 변화를 의미한다. 이러한 산업진화를 설명하는 이론은 기업 내지는 조직에 미치는 영향의 정도가 연속적인가 불연속적인가에 따라 크게 연속적 이론으로서의 제품수명주기이론과 불연속적 이론으로서 기술혁신이론과 규제이론으로 구분할 수 있다. 산업진화의 불연속성은 특정 기술이나 규제가 출현해 새로운 것으로 대체될 때까지의 과정이 혁신적이고 단속적인 변화를 거치는 것으로 정의될 수 있는데, 본 연구에서는 이러한 불연속성의 구체적 결과로서 신기술의 등장과 확산, 소비자 수요패턴의 변화, 그리고 산업내 경쟁구도의 변화의 3가지를 제시하였다. 여러 산업 중 공공재 산업과 공익재 산업은 특히 불연속적 산업진화의 특징이 두드러지는데, 본 연구에서는 공익재 산업 중 전용회선 산업을 중심으로 한국을 비롯 미국, 영국, 일본의 사례를 비교분석한 후 명제를 도출하였다. 요컨대, 산업진화의 불연속성은 기술혁신의 강도와 정책당국의 규제패턴에 의해 더욱 심화된다. This paper suggests two major factors which affect the discontinuities in industry evolution. The first factor refers to the technological discontinuities related to diffusion of emerging technologies. The second refers to the regulatory discontinuities related to the dynamics over time of structural variables: entry, exit, competitive structure, and concentration, as well as technological change. The leased line industry is sort of public utilities. It means that this industry is characterized by technological and regulatory discontinuities. In this paper, it has been conducted comparative case studies among the four countries: Korea, United States, United Kingdom and Japan. Through the multinational case studies, three findings are suggested. The first is that late mover in public utilities may accelerate technological innovation in the industry evolution. The second is that deregulation in public utilities can promote the emergence of a significant competitor that is equal conditioned with the dominant player. The last is that the appearance of a significant competitor may get more fierce competitions in the public utilities.

A Discontinuity Adaptive Markov Model for Color Image Smoothing

Kang, Dong Joong 동명정보대학교 2002 저널 정보공학기술 Vol.1 No.-

We present a new scheme to increase the performance of edge-preserving image smoothing from the parameter tuning of a Markov random field (MRF) function. The method is based on automatic control of the image smoothing-strength in MRF modeling in which an introduced parameter function is based on control of enforcing power of a discontinuity-adaptive Markov function and edge magnitude resulted from discontinuities of image intensity. Without any binary decision for the edge magnitude, adaptive control of the enforcing power with the full edge magnitude could improve the performance of discontinuity-preserving image smoothing.

Performance of pillar design in underground stone mines that include discontinuities

Hyung-Sik Yang,Won-Beom Kim,Mahrous A.M. Ali 한국자원공학회 2012 Geosystem engineering Vol.15 No.3

This paper describes a pillar design methodology that was developed from a study of pillar performance in operating stone mines. A number of methodologies have been developed to calculate full-scale mine pillar strengths based on laboratory scale strength obtained from specimens. Data were collected on rock mass quality, pillar conditions, mining dimensions and intact rock strength. Results showed that current mining practices have resulted in generally stable pillar layouts, without recent cases of extensive pillar collapses; however, failure of the pillars was found to be related to spalling of hard brittle rock, shearing along pre-existing angular discontinuities or progressive extrusion of soft infill material on bedding planes. A numerical model (FLAC3D) for the entire rock mass has been developed in order to analyze the stability of the entire underground opening. A preliminary monitoring phase has been realized, aimed at controlling abandoned rock structure movement at the most significant discontinuities. Some measurements of the vertical stress in the pillars and in the walls have also been performed and were used for model calibration. Once the model has been calibrated, analysis of the actual stress and deformation conditions can then be evaluated, the stability condition of the entire structure can be computed and a forecast analysis of what intervention could be realized to guarantee underground public access can be performed. The developed strength equation can be used to design stable pillar layouts, keeping in mind that the safety factor is greater than 1.5 and the width:height ratio of the pillars is between 0.6 and 0.8. It is concluded that, by applying the developed equation and selecting appropriate input parameters, it should then be possible to calculate the factor of safety.

온도검층과 수압시험을 통한 파쇄암반의 단열분포와 지하수 흐름 상관성 고찰

박승혁 ( Seunghyuk Park ),정일문 ( Il-moon Chung ) 대한지질공학회 2016 지질공학 Vol.26 No.4

장성군 지하수 기초조사 사업의 일환으로 전기비저항탐사를 수행하여 암반대수층의 정성적인 분포를 판별하고 이를 기반으로 관측정을 설치하였다. 온도검층, BIPS 영상자료, 공내 구간별 수압시험 해석을 통하여 지하수가 유동하는 투수성 단열구간의 위치를 파악하고 단열과 절리틈새의 분포특성과 위의 3가지 시험결과값의 상관성을 고찰해 본 결과 수압시험 결과로 나타난 루전값은 단열의 크기에 상관성을 갖고 온도검층 결과, 온도변화는 절리틈새의 크기에 상관성을 갖는 것으로 나타나 투수성 단열 분류시 온도검층이 효율적인 방법임을 확인하였다. The qualitative distribution of a fractured aquifer was characterized by electrical resistivity surveying as a part of basic groundwater investigation in Jangseong. The results were then used to choose sites for observation wells. The locations and distributions of permeable discontinuities were studied by analyses of temperature logs, a borehole image-processing system (BIPS), and hydraulic pressure testing using a double packer. The pressure test showed that the size of the discontinuities correlated with the Lugeon value and the results of the temperature log. The results show that temperature measurement is an effective method to identify permeable discontinuities, with the temperature difference correlating with the size of the aperture of the discontinuity.

FDTD법을 이용한 계단임피던스 기반의 마이크로스트립 불연속 특성 분석

이동학,양두영 한국지식정보기술학회 2016 한국지식정보기술학회 논문지 Vol.11 No.3

An analysis of discontinuity of microstrip transmission line, which is used to the microwave integrated circuit implementation, is very important work to be applied the complicated circuit design based on the multiport network and transmission line theory. In this paper, we treat the FDTD technique that encompasses the electromagnetic modeling, simulation, and analysis of the electromagnetic responses of the complex systems to various electromagnetic stimuli. It provides a understanding of the circuit response that allows for the better design or modification of the low pass circuit. And also, the simulation conditions to apply the FDTD method are proposed for the microstrip circuit design with multistep discontinuities. The conditions are to definition of the microstrip structure, source feeding waveform, CPML boundary condition and the numerical procedure of electromagnetic wave components. Therefore, the low pass circuits having the step-impedance structure composed of microstrip transmission line are analyzed by the FDTD method and the numerical results are compared with the measurement results in order to determine the accuracy. From the coherent results between the numerics and the measurements, the proposed simulation conditions of FDTD can be usefully used to design and realization of microstrip application circuits with the multistep structure.

휴대용 시추공 카메라를 이용한 지하정보의 가시화 기법

정윤영(Yun-Young Jeong),松井 紀久男(Kikuo Matsui) 한국암반공학회 2005 터널과지하공간 Vol.15 No.1

근래에 들어 진행된 시추공을 이용한 각종 측정 장비의 개발에 따라 지하정보의 가시화는 중요한 관심의 초점으로 대두되었다. 이를 위해 시추공벽 영상의 모니터링과 동시에 여러 가지 분석틀을 제공할 수 있는 장비가 개발되고 있으나 불량한 암반조건이나 소수의 엔진이어만이 접근할 수 있는 곳에서는 그 장비의 활용이 극히 제한적이디. 그리하여 최소한의 기능만을 보유하고 휴대가 가능한 시추공 카메라가 개발되어 상용화 되고 있다. 본 연구에서는 휴대용 시추공 카메라를 이용하여 얻은 지하정보를 토대로 암반 내에 발달해있는 불연속면의 분포를 3차원으로 가시화 히는 수리학적인 형식화 과정과 가시화된 이미지의 해석방법을 제시하고 이에 대한 사례연구로서 두 지역에 적용하였다. 형식화 과정은 3차원 공간좌표에서 불연속면의 방향성분(경사각, 경사방향 및 심도)이 지시한 위치관계를 시추공의 선주향(trend)와 주향경사(plunge)의 변화에 기초하여 고찰함을 의미하며, 그 결과 일련의 조건식을 유도한다. 두 지역에 대한 사례연구를 통해, 본 연구에서 제시한 가시화 기법이 국지적인 불연속면의 분포가 중요한 경우 지반공학적(geotechnical)으로 유용한 수단이 될 수 있음을 알 수 있다. According to the recent development of measurement system utilizing one or a set of boreholes, visualization of the explored underground became to be a major issue. It induced even the introduction of monitoring apparatuses on the borehole wall with multi-function tool, but the usage of these was often limited by where is unfavorable rock condition and a few of engineers can approach. And so, a portable type of borehole camera with only the essential function has been investigated and a few of commercial models about this is recently being applied into the field condition. This paper was based on the monitoring results obtained using a commercial model by Dr. Nakagawa. Discontinuities in rock mass were the topic for the visualization, and it was studied how can visualize their three dimensional distribution and what a numerical formulation is needed and how to understand the visualization result. The numerical formulation was based on the geometric correlation between the dip direction / dip of discontinuous plane and the trend / plunge of borehole, a set of the equation of a plane was induced. As field application of this into two places, it is found that the above visualization methodology will be especially an useful geotechnical tool for analyzing the local distribution of discontinuities.

Wideband Low-Reflection Transmission Lines for Bare Chip on Multilayer PCB

Rashad Ramzan,Jonas Fritzin,Jerzy Dabrowski,Christer Svensson 한국전자통신연구원 2011 ETRI Journal Vol.33 No.3

The pad pitch of modern radio frequency integrated circuits is in the order of few tens of micrometers. Connecting a large number of high-speed I/Os to the outside world with good signal fidelity at low cost is an extremely challenging task. To cope with this requirement, we need reflection-free transmission lines from an on-chip pad to on-board SMA connectors. Such a transmission line is very hard to design due to the difference in on-chip and on-board feature size and the requirement for extremely large bandwidth. In this paper, we propose the use of narrow tracks close to chip and wide tracks away from the chip. This narrow-to-wide transition in width results in impedance discontinuity. A step change in substrate thickness is utilized to cancel the effect of the width discontinuity, thus achieving a reflection-free microstrip. To verify the concept, several microstrips were designed on multilayer FR4 PCB without any additional manufacturing steps. The TDR measurements reveal that the impedance variation is less than 3 ohm for 50 ohm microstrip and S11 better than –9 dB for the frequency range 1 GHz to 6 GHz when the width changes from 165 um to 940 um, and substrate thickness changes from 100 um to 500 um.

Exploratory innovation and exploitative innovation in the phase of technological discontinuity: the perspective on patent data for two IC foundries

Hsien-Che Lai,Calvin S. Weng 기술경영경제학회 2016 ASIAN JOURNAL OF TECHNOLOGY INNOVATION Vol.24 No.1

This study investigates how firms manage different innovation modes in the context oftechnological discontinuities. Using the aluminium-to-copper transition process, wecollected patent data from the time period 1997 to 2001 for the top two firms in the ICfoundry industry, the Taiwan Semiconductor Manufacturing Company and the UnitedMicroelectronic Corporation. We suggest that environmental responsiveness to technologicaluncertainty can provide a background for understanding how incumbent firms respond tomanagerial challenges associated with the exploratory–exploitative innovation tension. Thestatistical results indicate that incumbent firms simultaneously conduct exploratory andexploitative innovation and, furthermore, engage in significantly more exploratoryinnovation than exploitative innovation when faced with technological discontinuities.