• Title/Summary/Keyword: stability theory

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Exploratory Research of Possibilities and Limiatation of Drone Journalism (재난재해 대응수단으로 드론저널리즘의 가능성과 한계에 관한 탐색적 연구)

  • Cho, Hang-Min
    • Journal of Digital Convergence
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    • v.16 no.8
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    • pp.71-79
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    • 2018
  • This study discussed the meaning of a drone, and especially drone journalism and legal and ethical issues around that, at an introductory dimension, which is used in various social bases, but is still just an academic discussion at the beginning stage. As a methodology, content analysis was used. It seems that drone journalism has high diffusibility as a technology with high 'relative advantage', 'compatibility', 'trial ability' and 'observability' and low 'complexity' in terms of the diffusion of innovation theory. However, it will be very likely that controversies will be raised, such as safety issue due to collision and crash, a dispute over violation of privacy that may seriously infringe privacy like individual portrait rights and a controversy about the accuracy and source of information as drone filming low price and ease of use. Suggest solutions to legal and ethical issues based on existing research. Technical stability is required. Also, it is necessary to change the awareness of journalists about the drones coverage and to educate ethics, and it is necessary to establish social public opinion on issues such as privacy violation and establish system and legal measures through it. Future research is expected to carry out empirical research including journalists and public awareness surveys.

Defect Depth Measurement of Straight Pipe Specimen Using Shearography (전단간섭계를 이용한 직관시험편의 결함 깊이 측정)

  • Chang, Ho-Seob;Kim, Kyung-Suk
    • Journal of the Korean Society for Nondestructive Testing
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    • v.32 no.2
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    • pp.170-176
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    • 2012
  • In the nuclear industry, wall thinning defect of straight pipe occur the enormous loss in life evaluation and safety evaluation. To use non-destructive technique, we measure deformation, vibration, defect evaluation. But, this techniques are a weak that is the measurement of the wide area is difficult and the time is caught long. In the secondary side of nuclear power plants mostly used steel pipe, artificiality wall thinning defect make in the side and different thickness make to the each other, wall thinning defect part of deformation measure by using shearography. In addition, optical measurement through deformation, vibration, defect evaluation evaluate pipe and thickness defects of pressure vessel is to evaluate quantitatively. By shearography interferometry to measure the pipe's internal wall thinning defect and the variation of pressure use the proposed technique, the quantitative defect is to evaluate the thickness of the surplus. The amount of deformation use thickness of surplus prediction of the actual thickness defect and approximately 7 percent error by ensure reliability. According to pressure the amount of deformation and the thickness of the surplus through DB construction, nuclear power plant pipe use wall thinning part soundness evaluation. In this study, pressure vessel of thickness defect measure proposed nuclear pipe of wall thinning defect prediction and integrity assessment technology development. As a basic research defected theory and experiment, pressure vessel of advanced stability and soundness and maintainability is expected to contribute foundation establishment.

A Comparison of the Difference in the Golf Swing Motion According to Somatotypes (체형에 따른 골프 스윙 동작 비교)

  • Chung, Nam-Ju;Yoon, Hee-Joong;Baik, Young-Soo
    • Korean Journal of Applied Biomechanics
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    • v.12 no.2
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    • pp.33-49
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    • 2002
  • This study was intended to provide basic materials for golf coaching by somatotype by analyzing and comparing the kinematic factors found in each somatotype at the time of golf swing. For this purpose, the somatotype was divided into endomorph, mesomorph and ectomorph in reference to the weight, height and upper arm circumference of each of nine professional golfers. Each of their swing motions was videotaped with the camcorder and their swing motion was analyzed by dividing it into 8 sections. The time required for the swing motion, the displacement of the center of the human body and the rotation angle of the upper body were calculated through the three-dimensional image analysis based on the DLT(Direct Linear Transformation). Based on the findings of this study, the following conclusion was drawn: The endomorphic golfers showed the longest required golf swing time, followed by the mesomorphic golfer and then the endomorphic golfer. The displacement of left-to-right movement was largest in the mesomorphic golfers, followed by the endomorphic golfers the up-to-down displacement was upward at the time of impact and that the endomorphic and mesomorphic golfers raised the sense of stability by maintaining an almost uniform height at the time of impact. As for the rotational angle of the upper body and the rotational angle of the thigh, the upper body and the thigh took a form of rotating earlier in the ectomorphic golfers at the time of impact, who showed a somewhat different characteristics compared to the endomorphic and mesomorphic golfers. It is necessary to investigate the movement of more fundamental forces in presenting the theory related to the kinematic characteristics of this swing by somatotype. Accordingly, it is thought that it is necessary to analyze the center of pressure(COP) using the ground counterforce in the future study.

Analyzing Dynamics of Korean Housing Market Using Causal Loop Structures (주택시장의 동태성 분석을 위한 시스템 사고의 적용에 관한 연구 - 인과순환지도를 중심으로 -)

  • Shin Hye-Sung;Sohn Jeong-Rak;Kim Jae-Jun
    • Korean Journal of Construction Engineering and Management
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    • v.6 no.3 s.25
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    • pp.144-155
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    • 2005
  • Since 1950s, the Korean housing market has continually experienced the chronicle lack of housing stock because of lower housing investment in comparison with a population explosion, prompt urbanization and rapid restructuring of family. The Korean housing market have thus been driven not by the pricing model by housing demand-supply chain but by the Korean housing policies focusing on the increase of housing supply and the living stability of the middle or low-income bracket. After all, repetitive economic vicious circle of housing price and the increase of unsold apartments aggravated the malfunction of the Korean housing market. Meanwhile, the Korean construction firms have exacerbated their profitability. Such terrible situations are mainly triggered by the Korean construction firms that weighed on the short-term profits and quick response of the government policy alterations rather than the prospect of housing market Therefore, this research focusing on the dynamics of housing market identified and classified the demand and supply elements that consist not only of housing system structures but also of the environmental elements that affect the structures. Based on the system thinking and traditional theory of consumer's choice, the interactions of these elements were constructed as a causal loop diagram that explains the mutual influences among housing subsystems with feedback loops. This paper describes and discusses about the causes of the dynamic changes in the Korean housing market. This study would help housing suppliers, including housing developers, construction firms, etc., to form a more comprehensive understanding on the fundamental issues that constitute the Korean housing market and thereby increasing their long term as well as minimizing the risk involved in the housing supply businesses.

Multi-modality MEdical Image Registration based on Moment Information and Surface Distance (모멘트 정보와 표면거리 기반 다중 모달리티 의료영상 정합)

  • 최유주;김민정;박지영;윤현주;정명진;홍승봉;김명희
    • Journal of KIISE:Computer Systems and Theory
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    • v.31 no.3_4
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    • pp.224-238
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    • 2004
  • Multi-modality image registration is a widely used image processing technique to obtain composite information from two different kinds of image sources. This study proposes an image registration method based on moment information and surface distance, which improves the previous surface-based registration method. The proposed method ensures stable registration results with low registration error without being subject to the initial position and direction of the object. In the preprocessing step, the surface points of the object are extracted, and then moment information is computed based on the surface points. Moment information is matched prior to fine registration based on the surface distance, in order to ensure stable registration results even when the initial positions and directions of the objects are very different. Moreover, surface comer sampling algorithm has been used in extracting representative surface points of the image to overcome the limits of the existed random sampling or systematic sampling methods. The proposed method has been applied to brain MRI(Magnetic Resonance Imaging) and PET(Positron Emission Tomography), and its accuracy and stability were verified through registration error ratio and visual inspection of the 2D/3D registration result images.

3D analysis of fracture zones ahead of tunnel face using seismic reflection (반사 탄성파를 이용한 터널막장 전방 파쇄대의 3차원적 예측)

  • Lee, In-Mo;Choi, Sang-Soon;Kim, Si-Tak;Kim, Chang-Ki;Jun, Jea-Sung
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.4 no.4
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    • pp.301-317
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    • 2002
  • Recently, a geophysical exploration technology is frequently utilized in the civil engineering field as well as in the resource exploration. It might be important for civil engineers to understand the fundamental theory of seismic survey and limitation of the technique when utilizing these techniques in the civil engineering field. A 3-dimensional migration technique based on the principle of ellipsoid to predict the fractured zone ahead of tunnel face utilizing the tunnel seismic survey was proposed so that the geometry of the fractured zone can be estimated, i.e. the angle between tunnel axis and discontinuity zone, and the dip. Moreover, a numerical analysis technique to simulate the TSP (Tunnel Seismic Prediction) test was proposed in this paper. Based on parametric studies, the best element size, the analysis time step, and the dynamic characteristics of pressure source were suggested to guarantee the stability and accuracy of numerical solution. Example problems on a hypothetical site showed the possibility that the 3-dimensional migration technique proposed in this paper appropriately estimate the 3D-geometry of fractures ahead of tunnel face.

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Legislation Cases, Management Policies and Countermeasures on Scientific Data -Focusing Australia, the United States and China- (과학데이터에 관한 입법례와 관리정책 그리고 대응방안 -호주, 미국, 중국을 중심으로-)

  • Yoon, Chong-Min;Kim, Kyubin
    • Journal of Korea Technology Innovation Society
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    • v.16 no.1
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    • pp.63-100
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    • 2013
  • Research data means data in the form of facts, observations, images, computer program results, recordings, measurements or experiences on which an argument, theory, test or hypothesis, or another research output is based. Data may be numerical, descriptive, visual or tactile. Scientific research is changing because of the paradigm shift. It is all being affected by the data deluge, and a data-intensive science paradigm is emerging. Hence, paradigm shift in scientific research led to increase of value and importance of scientific data. Essential to the creative research and development for scientific data can be reused efficiently is the sharing and utilization of establishing management system. Establishing of management system for sharing and utilization of scientific data should be done at the national level, but compared with Europe, Australia, the United States, China, the management system of Korea doesn't have not linkage or efficiency or internal stability. Australia, the United States, China continues to expand a Mid- and Long-Term policy making, legislation, its investment in infrastructure, so as to promote the utilization of data, such as collection, management and maintenance of scientific data through the relevant agencies at the national level. This study consider legislation cases and management policies of the above countries to the end to that establish management system for the efficient and fair sharing and utilization of scientific data and the legal system, and that provide scientific data legislation and policies related to the future of our country.

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Slow Cook-Off Test and Evaluation for HTPE Insensitive Propellants (HTPE 둔감추진제 완속가열 시험평가)

  • Yoo, Ji-Chang;Kim, Chang-Kee;Kim, Jun-Hyung;Lee, Do-Hyung;Min, Byung-Sun
    • Journal of the Korean Society of Propulsion Engineers
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    • v.14 no.6
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    • pp.31-37
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    • 2010
  • This study was carried out to investigate the thermal decomposition and execute EIDS slow cook-off test for the propellant ingredients and 2 kinds of HTPE propellants. The thermal analysis of the propellant ingredients used in this study showed that the thermal stability of these materials decreases in the following order : AP > HTPE > AN > BuNENA. In addition, propellant HTPE 002 containing AN showed that an endothermic process at around $125^{\circ}C$ corresponding to the solid phase change(II$\rightarrow$I) of AN was followed by the exothermic process of BuNENA/AN mixture up to $200^{\circ}C$. In EIDS slow cook-off tests, HTPE 001 and HTPE 002 reacted at around $250^{\circ}C$ and $152^{\circ}C$ respectively, and both of them showed sudden temperature increase curves at $115^{\circ}C$. The critical temperatures, $T_c$, of thermal explosion for the propellants HTPE 001 and HTPE 002, were obtained from both the non-isothermal curves at various heating rates and Semenov's thermal explosion theory. Kissinger's method that was used to calculate $T_c$ was also employed to obtain the activation energies for thermal decompositions.

Derivation and verification of electrical resistivity theory for surrounding ground condition prediction of TBM (TBM 주변 지반상태예측을 위한 전기비저항 이론식 유도 및 검증)

  • Hong, Chang-Ho;Lee, Minhyeong;Cho, Gye-Chun
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.22 no.1
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    • pp.135-144
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    • 2020
  • Since the depth of tunneling with tunnel boring machine (TBM) becomes deeper and deeper, the expense for site investigation for coring and geophysical survey increases to obtain the sufficient accuracy. The tunnel ahead prediction methods have been introduced to overcome this limitation in the stage of site investigation. Probe drilling can obtain the core and borehole images from a borehole. However, the space in TBM for the probe drilling equipment is restricted and the core from probe drilling cannot reflect the whole tunnel face. Seismic methods such as tunnel seismic prediction (TSP) can forecast over 100 m ahead from the tunnel face though the signal is usually generated using the explosive which can affect the stability of segments and backfill grout. Electromagnetic methods such as tunnel electrical resistivity prospecting system (TEPS) offer the exact prediction for a conductive zone such as water-bearing zone. However, the number of electrodes installed for exploration is limited in small diameter TBM and finally the reduction of prediction ranges. In this study, the theoretical equations for the electrical resistivity survey whose electrodes are installed in the face and side of TBM to minimize the installed electrodes on face. The experimental tests were conducted to verify the derived equations.

Temporary Metadata Journaling Scheme to Improve Performance and Stability of a FAT Compatible File System (FAT 파일 시스템의 호환성을 유지하며 성능과 안정성을 향상시키는 메타데이터 저널링 기법의 설계)

  • Hyun, Choul-Seung;Choi, Jong-Moo;Lee, Dong-Hee;Noh, Sam-H.
    • Journal of KIISE:Computer Systems and Theory
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    • v.36 no.3
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    • pp.191-198
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    • 2009
  • The FAT (File Allocation Table) compatible file system has been widely used in mobile devices and memory cards because of its data exchangeability among numerous platforms recognizing the FAT file system. By the way. modern embedded systems have tough demands for instant power failure recovery and superior performance for multimedia applications. The key issue is how to achieve the goals of superior write performance and instant booting capability while controlling compatibility issues. To achieve the goals while controlling compatibility issues. we devised a temporary meta-data journaling scheme for a FAT compatible file system. Benchmark results of the scheme implemented in a FAT compatible file system shows that it really improves write performance of the FAT file system by converting small random write for meta-data update to a large sequential write in journaling area. Also, it provides natural way to implement the instant booting capability. Nevertheless, the file system compatibility is temporarily compromised by the scheme because it stores updated meta-data in the temporary journaling area rather than to their original locations. However, the compatibility can be fully recovered at any time by journal-flushing that copies meta-data in journaling area to their original locations. Generally, the journal-flushing is done before un-mounting a memory card so that it can be used in other mobile devices which recognized FAT file system but not the temporary meta-data journaling scheme.