• Tunnel and Underground Space
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• v.29 no.6
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• pp.379-393
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• 2019

For the economical construction of a tunnel by TBM, the selection of TBM optimized with the various project conditions is important, and also necessary to predict the performances of selected TBM in advance. This study was conducted to comprehensively evaluate the performance of the EPB shield TBM screw conveyor by the discrete element method. The sticky particles were used for the excavated material models, and screw conveyor with 11 different inclined angles were simulated to evaluate the performance depending on the different inclined angles. The four different rotational speed conditions of the screw were used, and torque, required power, extra energy for muck discharge, and the muck discharge rate were selected as four performance indicators. As a result, the optimized inclined angle was selected, and selected angle accords with the fact that EPB shield TBM screw conveyor is generally installed and adjusted at the inclined angle between 20.0° and 30.0° in the field.

• Journal of Navigation and Port Research
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• v.34 no.5
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• pp.367-373
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• 2010

When the numerical analysis is carried out, it is necessary to set proper elements as a feature of analysis domains for more accurate simulations. In this study, Distinct Element Method(DEM) is applied, only considering repulsive force and tensile force except for frictional force and resisting force of particle. When the filled particles with initial Quad-tree type is relocated by DEM, a blank space existing among the particles can be minimized because the shape of particle is circular. Finally, it is the effective feature that the centroidal disposion of the particles is similar to an equilateral triangle. Triangular mesh are formed by using the Delaunay triangular technique on these relocated particles, the quality of triangular mesh is more improved by carrying out Laplace interpolations. The compared result of Aspect Ratio before and after the Laplace interpolation is shown that although the quality of triangular mesh made by DEM is good, the later triangular mesh are higher quality than the formers. In this study, although the developed technique takes a longer calculational time than the previous technique to generate triangular mesh, it is considered that the applicable possibility is very high in the generation of finite element mesh about wave analysis and various numerical simulation to need a complex or reappearance of exact topography.

• The Journal of Engineering Geology
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• v.33 no.4
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• pp.573-586
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• 2023

Joints or weak planes can induce anisotropy in the strength and deformability of fractured rock masses. Comprehending this anisotropic behavior is crucial to engineering geology. This study used plaster as a friction material to mold specimens with a single joint. The strength and deformability of the specimens were measured in true triaxial compression tests. The measured results were compared with three-dimensional numerical analysis based on the distinct element method, conducted under identical conditions, to assess the reliability of the modeled values. The numerical results highlight that the principal stress conditions in the field, in conjunction with joint orientations, are crucial factors to the study of the strength and deformability of fractured rock masses. The strength of a transversely isotropic rock mass derived numerically considering changes in the dip angle of the joint notably increases as the intermediate principal stress increases. This increment varies depending on the dip of the joint. Moreover, the interplay between the dip direction of the joint and the two horizontal principal stress directions dictates the strength of the transversely isotropic rock mass. For a rock mass with two joint sets, the set with the steeper dip angle governs the overall strength. If a rock bridge effect occurs owing to the limited continuity of one of the joint sets, the orientation of the set with longer continuity dominates the strength of the entire rock mass. Although conventional three-dimensional failure criteria for fractured rock masses have limited applicability in the field, supplementing them with numerical analysis proves highly beneficial.

• Journal of Korean Library and Information Science Society
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• v.48 no.3
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• pp.45-61
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• 2017

The objective of this study is to understand the application of relative location system and minute classification system in the DDC and to identify the effect of the relative location system and minute classification system during the late of 19th century. In order to achieve the objective, four main investigation areas were chosen: relative location system, minute classification system, and DDC influence to other libraries and classification systems. First, DDC applied a relative location system revolutionarily instead of a fixed location system for arranging books on the shelves, so it opened the period of modern library classification systems. Second, it used a minute classification system, and could classify books which had minute subjects. Third, it applied form to a criterion for dividing divisions and sections, so it helped for classifying books. Fourth, it used a numerical decimal system as a classification system, then people could use it economically and practically. Last, DDC influenced modern classification system such as the Expansive Classification and the Subject Classification etc. DDC is a suitable library classification system for the needs of the times, and it is a practical classification system for each library.

• The KIPS Transactions:PartB
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• v.9B no.2
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• pp.223-230
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• 2002

In a speech coding system using excitation source of voiced and unvoiced, it would be involves a distortion of speech waveform in case coexist with a voiced and an unvoiced consonants in a frame. This paper present a new method of TSIUVC (Transition Segment Including Unvoiced Consonant) approximate-synthesis by using Least Mean Square. The TSIUVC extraction is based on a zero crossing rate and IPP (Individual Pitch Pulses) extraction algorithm using residual signal of FIR-STREAK Digital Filter. As a result, This method obtain a high Quality approximation-synthesis waveform by using Least Mean Square. The important thing is that the frequency signals in a maximum error signal can be made with low distortion approximation-synthesis waveform. This method has the capability of being applied to a new speech coding of Voiced/Silence/TSIUVC, speech analysis and speech synthesis.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.7 no.1
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• pp.87-106
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• 2001

슬링 운동 치료(Sling Exercise Therapy)는 근골격계 질환 환자의 영구적인 치유를 목적으로 슬링을 이용한 능동적인 치료와 운동법을 체계화한 접근법이다. 이 개념은 10 여년 전부터 노르웨이의 물리치료사들을 중심으로 발전되어 왔으며, 현재 뇌졸중 환자와 신경학적 질환자 그리고 소아 환자와 건강 증진 프로그램에서도 이용되는 방법들이 개발되어지고 있다. 현재 정형물리치료 분야에 대한 세계적인 흐름은 전기치료 기구나 물리치료사의 손에 의해 수동적으로 이루어지는 치료 접근에서 점차 환자가 스스로 물리치료사에 의해 특별히 고안된 운동방법에 따라 능동적인 치료적 운동을 통해 손상 치료와 건강 관리를 하는 방향으로 발전되어지고 있으면 많은 치료 분야에서 이러한 접근법을 채택하고 있다. 슬링운동치료 개념은 이러한 능동적인 운동법을 주된 목적으로 이용하고 있다. 이 논문은 근골격계 질환의 치료를 중심으로 쓰여졌다. SET 개념에는 체계적인 진단과 치료의 요소들이 포함되어져 있다. 진단 체계에는 열린 사슬과 닫힌 사슬을 이용하여 단계적으로 부하를 가해 줌으로서 근육의 상태를 검사하는 방식을 가지고 있다. 치료적 체계를 구성하는 요소에는 근육의 안정화, 감각운동 훈련, 열린 사슬과 닫힌 사슬을 이용한 훈련법, 가동성있는 연부 조직의 역동적 훈련, 심폐 강화 훈련, 단체 훈련, 가정에서의 개별적 훈련과 추후 관리 그리고 운동 프로그램을 제공하기 위한 컴퓨터 소프트웨어가 포함되어 있다.

• Journal of the Korea institute for structural maintenance and inspection
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• v.12 no.5
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• pp.143-151
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• 2008

In this paper, the optimum design of plane steel frames using second-order inelastic analysis and section increment method is presented. Since the second-order inelastic analysis accounts for geometric and material nonlinearities of the whole system as well as its component members, the design method based on second-order inelastic analysis does not require separate member capacity checks after analysis. A section increment method proposed by this paper is used as optimization technique. The weight of structures is treated as the objective function. The constraint functions are defined by load-carrying capacities, deflections, inter-story drifts, and ductility requirement. The effectiveness of the proposed method are verified by comparing the results of the proposed method with those of other method.

• The Korean Journal of Air & Space Law and Policy
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• v.35 no.3
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• pp.151-208
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• 2020

Japan's two outer space-related laws were promulgated on November 16, 2016. There are the Act on Launching of Spacecraft, etc. and Control of Spacecraft (Act No. 76 of 2016, Space Activities Act) and the Act on Securing Proper Handling of Satellite Remote Sensing Records (Act No.77 of 2016, Remote Sensing Records Act). Japan's Space Activities Act states that a person who launches a satellite from the territory of Japan, or from a ship or airplane registered in Japan, must obtain permission from the Prime Minister prior to the launch. To obtain the permission, the person must have a certificate for a rocket design and for radio equipment at a launching facility. In addition, the ability to launch a rocket safely and the purpose for the satellite launch must be evaluated. Managing a satellite from Japan also requires permission from the government. A person who launches a rocket must have insurance for any potential damage arising from accidents, and the government is to supplement the potential compensation to allow for damage that cannot be covered by private insurance. The purpose of this paper reviews regulations of launch services and management of satellites in the Japan's Space Activities Act. It also offers some implications and suggestions for regulations of launching of spacecraft and management or operation of satellites.

• Geophysics and Geophysical Exploration
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• v.12 no.1
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• pp.85-98
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• 2009

The tau-p inversion algorithm is widely employed to generate starting models with most computer programs, which implement refraction tomography. This algorithm emphasises the vertical resolution of many layers, and as a result, it frequently fails to detect even large lateral variations in seismic velocities, such as the decreases which are indicative of shear zones. This study demonstrates the failure of the tau-p inversion algorithm to detect or define a major shear zone which is 50m or 10 stations wide. Furthermore, the majority of refraction tomography programs parameterise the seismic velocities within each layer with vertical velocity gradients. By contrast, the Generalized Reciprocal Method (GRM) inversion algorithms emphasise the lateral resolution of individual layers. This study demonstrates the successful detection and definition of the 50m wide shear zone with the GRM inversion algorithms. The existence of the shear zone is confirmed by a 2D analysis of the head wave amplitudes and by numerous closely spaced orthogonal seismic profiles carried out as part of a later 3D refraction investigation. Furthermore, an analysis of the shot record amplitudes indicates that a reversal in the seismic velocities, rather than vertical velocity gradients, occurs in the weathered layers. The major conclusion reached in this study is that while all seismic refraction operations should aim to provide as accurate depth estimates as is practical, those which emphasise the lateral resolution of individual layers generate more useful results for geotechnical and environmental applications. The advantages of the improved lateral resolution are obtained with 2D traverses in which the structural features can be recognised from the magnitudes of the variations in the seismic velocities. Furthermore, the spatial patterns obtained with 3D investigations facilitate the recognition of structural features such as faults which do not display any intrinsic variation or 'signature' in seismic velocities.

• Journal of Korea Water Resources Association
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• v.38 no.10 s.159
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• pp.811-824
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• 2005

The ADCP is an instrument based on Doppler effect, which measures discharge of a river in a short time while crossing it. In this study we aim to make a comparison of the discharge results from a moving-vessel ADCP with those measured by velocity-area method at the same cross-section, and to investigate the characteristics of velocity and discharge data using ADCP. Bathymetry measured by ADCP almost coincides with that by direct depth measurements. Because velocity data from ADCP are essentially instantaneous, individual velocity profiles obtained by ADCP are rather different from time-averaged velocity profiles. But spatially averaged velocity profiles of the individual ADCP data near the comparable verticals have similar vertical velocity pattern with the time-averaged ones. The average velocity profile from repeatedly crossed data is also similar with the time-averaged one. In case of the velocity distribution, individual and spatially averaged data for the sub-width of mid-section method Have good agreement with those by velocity-area method. Discharge data determined by averaging several ADCP measurement transects have $0.1\%{\~}9.3\%$ of difference with those from velocity-area method, and as the number of measurement increases, the relative difference to the velocity-area method decreases.