• Title/Summary/Keyword: Water Object

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Control of an Underwater Stereo Camera Embedded in a Single Canister Capable of Measuring Distance (거리측정이 가능한 단동형 수중 스테레오 카메라의 제어)

  • 이판묵;전봉환;이종무
    • Journal of Ocean Engineering and Technology
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    • v.15 no.1
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    • pp.79-84
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    • 2001
  • This paper present the control of the image disparity of a parallel stereo camera and its application to an underwater stereo camera to enhance the working efficiency of underwater vehicles that are equiped with manipulators in seabed operation. The stereo camera consists of two parallel lenses mounted on a lateral moving base and two CCD cameras mounted on a longitudinal moving base, which is embedded in a small pressure canister for underwater application. Because the lateral shift is related to the backward shift with a nonlinear relation, only one control input is needed to control the vergence and focus of the camera with a special driving device. We can get clear stereo vision with the camera for all the range of objects in air and in water, especially in short range object. The control system of the camera is so simple that we are able to realize a small stereo camera system and apply it to a stereo vision system for underwater vehicles. This paper also shows how to acquire the distance information of an underwater object with this stereo camera. Whenever we focus on an underwater object with the camera, we can obtain three-dimensional images and distance information in real-time.

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A Study on the Use of Police Force in the Public Assembly: Focused on the Vehicle-wall-blocking and water cannon (집회현장에서의 경찰의 물리력 사용현황과 개선방안: 차벽과 물포 사용을 중심으로)

  • Hwang, Mun-Gyu
    • Korean Security Journal
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    • no.50
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    • pp.307-337
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    • 2017
  • The freedom of assembly is the fundamental freedoms guaranteed by the Constitution. However, as far as our reality is concerned, the freedom of assembly is guaranteed only when it is under the control of the police, and otherwise it is perceived as an object to be suppressed. Police say even that they will not tolerate even a small illegal law while referring to the "broken window theory". Therefore, regardless of the peaceful nature of the rally, it is too obsessed with 'compliance'. This attitude is causing the citizens who participated in the assembly to be put to the object to be suppressed. This paper analyzes the requirements and current status of police force, focusing on the vehicle-wall-blocking and water cannon as a means of using the police force, which is a recent problem, and suggests ways to improve it. First of all, the installation of the wall cuts off the essential communication function of the assembly by separating the meeting place from the object of protest. Thus, despite the warning for prevention in the face of illegal acts, other than installing a barrier, it should be allowed only in the 'urgent case where there is a risk of causing damage to the life, body or property of the person'. Without this urgency, the vehicle-wall-blocking should not be allowed to be proactive as well as preventive. Secondly, the water cannon is a police force that is likely to harm people's life and body. Therefore, aiming shots, which could pose a significant risk to the human body, should in principle be prohibited. However, considering its risk, it should be supplementary used only when there is no other alternative, only when the direct risk to the legal interest of the other person or the order of public well-being is 'obvious'. In addition, as for the use standard of such a thing, it is necessary to be specified by law.

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Coupled simulation of grid-based fluid and mass-spring based deformation/fracture (질점-용수철 기반변형/파괴 물체와 격자 기반 유체의 상호작용 시뮬레이션 기술)

  • Kim, Bong-Jun;Lim, Jae-Gwang;Hong, Jeong-Mo
    • Journal of the Korea Computer Graphics Society
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    • v.20 no.4
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    • pp.9-16
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    • 2014
  • This paper proposes a novel method that couples fluid and deformation/fracture. Our method considers two interaction types: fluid-object interaction and fluid-fluid interaction. In fluid-fluid interaction, we simulate water and smoke separately and blend their velocities in the intersecting region depend on their densities. Our method separates projection process into two steps for each of water and smoke. This reduces the number of grid cells required for projection in order to optimize the number of iterations for convergence and improve stability of the simulation. In water projection step, smoke region regarded as the cells with Dirichlet boundary condition. The smoke projection step solves water region with Neumann boundary condition. To take care of fluid-object interaction, we make use of the fluid pressure to update velocities of the each of the mass points so that the object can deform or fracture. Although our method doesn't provide physically accurate results, the various examples show that our method generate appealing visuals with good performance.

Research on heat transfer coefficient of supercritical water based on factorial and correspondence analysis

  • Xiang, Feng;Tao, Zhou;Jialei, Zhang;Boya, Zhang;Dongliang, Ma
    • Nuclear Engineering and Technology
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    • v.52 no.7
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    • pp.1409-1416
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    • 2020
  • The study of heat transfer coefficient of supercritical water plays an important role in improving the heat transfer efficiency of the reactor. Taking the supercritical natural circulation experimental bench as the research object, the effects of power, flow, pipe diameter and mainstream temperature on the heat transfer coefficient of supercritical water were studied. At the same time, the experimental data of Chen Yuzhou's supercritical water heat transfer coefficient was collected. Through the factorial design method, the influence of different factors and their interactions on the heat transfer coefficient of supercritical water is analyzed. Through the corresponding analysis method, the influencing factors of different levels of heat transfer coefficient are analyzed. It can be found: Except for the effects of flow rate, power, power-temperature and temperature, the influence of other factors on the natural circulation heat transfer coefficient of supercritical water is negligible. When the heat transfer coefficient is low, it is mainly affected by the pipe diameter. As the heat transfer coefficient is further increased, it is mainly affected by temperature and power. When the heat transfer coefficient is at a large level, the influence of the flow rate is the largest at this time.

Correlation Analysis of Water Quality According to Land Use Types of Reservoir Watershed (유역 토지이용과 저수지 수질의 상관관계 분석)

  • Youn, Dong-Koun;Chung, Sang-Ok
    • Proceedings of the Korean Society of Agricultural Engineers Conference
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    • 2005.10a
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    • pp.614-619
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    • 2005
  • The object of this study was to presented regression equations for obtaining simply and quickly values of water quality items, BOD, COD, T-N, and T-P. Regression equations obtained to analyze relationships for water quality items to land use types in agricultural reservoir watersheds. In order to derive regression equations, a multiple linear regression analysis was used in this studying reservoirs. In this regression analysis, a independent values used land used types and dependent values used BOD, COD, T-N, T-P values in water quality items. The results showed that numbers of regression equation ranging above 0.90 in a multiple correlation coefficient (MCC) was not found, ranging from 0.70 to 0.90 in the MCC was 6, ranging from 0.40 to 0.70 in the MCC was 20, and ranging from 0.20 to 0.40 in the MCC was 4. The results of this study can be used as a basic information for evaluating simply and quickly water quality for proposing and designing steps in water quality policy.

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A Study on Thermal Performance of Micro Channel Water Block for Computer CPU Cooling (컴퓨터 CPU 냉각용 미세채널 워터블록의 열성능에 관한 연구)

  • Kwon, Oh-Kyung;Choi, Mi-Jin;Cha, Dong-An;Yun, Jae-Ho
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.32 no.10
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    • pp.776-783
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    • 2008
  • The object of this paper is to study on the thermal performance of a micro channel water block for computer CPU cooling. The effects of liquid flow rate, micro channel width and height on the thermal performances of water block are investigated experimentally. The water block was fabricated Al and machined with a micro milling. The water block consisted of rectangular micro channels 0.5 to 0.9 mm width and 1.5 to 4.5 mm height. The experiments were conducted using deionized water, over a liquid flow rate ranging from 0.2 to 2.0 kg/min. The base temperature and thermal resistance decrease with increasing of liquid flow rate. The increase of a channel height is more effective on the thermal resistance than the decrease of a channel width. At the flow rate of 0.7 kg/min, input power of 100 W, the base temperature and thermal resistance of sample 6 is $33^{\circ}C$ and $0.13\;^{\circ}C/W$ respectively.

An Experimental Study for Relationship Between Gravity Water Content and Volumetric Water Content Through the Absorptance of Soils Particles (흙 입자의 흡수율을 고려한 체적함수비와 중량함수비의 관계에 관한 실험적 고찰)

  • Lee, Hyoungkyu;Lee, In
    • Journal of the Korean GEO-environmental Society
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    • v.12 no.3
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    • pp.63-67
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    • 2011
  • Recently, the application of unsaturated-soil theory is concerned in practice. Most characteristics of unsaturated-soil is the relationship between volumetric water contents and matric suction. Usually the volume water contents is estimated by the relationship between gravity water contents and volume water contents because of the difficulty of measurement of volumetric water contents. In this case, the water exists in only void of soil, and the relationship between gravity water contents and volume water contents is calculated by only water in void, but in fact, the water exists in the particle of the soil. So the real volume water contents is different with calculated volume water contents derived by the relationship containing only void water. The object of this research is to revise the relationship between volume water contents and gravity water contents by using the absorptivity tests of the soil particle.

A Study on Linear Spectral Mixing Model for Hyperspectral Imagery with Geometric Method (기하학적 기법을 이용한 하이퍼스펙트럴 영상의 Linear Spectral Mixing모델에 관한 연구)

  • 장은석;김대성;김용일
    • Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
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    • 2003.11a
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    • pp.23-29
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    • 2003
  • Detection in remotely sensed images can be conducted spatially, spectrally or both [2]. If the images have high spatial resolution, materials can be detected by using spatial and spectral information, unless we can't see the object embedded in a pixel. In this paper, we intend to solve the limit of spatial resolution by using the hyperspectral image which has high spectral resolution. Therefore, the Linear Spectral Mixing(LSM) Model which is sub-pixel detection algorithm is used to solve this problem. To find class Endmembers, we applied Geometric Model with MNF(Minimum Noise Fraction) transformation. From the result of sub-pixel detection algorithm, we can see the detection of water is satisfied and the object shape cannot be extracted but the possibility of material existence can be identified.

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Motion analysis of a VLCO for wave power generation (파력발전용 가변수주진동장치의 운동해석)

  • Lee, Seung-Chul;Goo, Ja-Sam
    • Journal of Power System Engineering
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    • v.18 no.3
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    • pp.36-41
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    • 2014
  • The structure of a variable liquid column oscillator(a VLCO) is analogous to that of the tuned liquid column damper used to suppress oscillatory motion in large structures like tall buildings and cargo ships. The VLCO is a system absorbing high kinetic energy of accelerated motions of the multiple floating bodies in the effect of air springs occurred by installation of inner air chambers. Thus, VLCO can improve the efficiency of energy than wave energy converters of the activating object type made in Pelamis Company. In this research, the experiment was performed in two models of same draft. The one is that weights were filled, and the other is that water was filled. The numerical results were estimated by assuming that do not exist internal flow, and the results were compared with the results of experiments.

A Study on the Development Rural Stream Environment Management System Using Object Oriented Programming (OOP) (객체지향기법을 이용한 농촌하천환경관리시스템 개발에 관한 연구)

  • Lee, Sung-Hack;Chung, Ha-Woo;Kim, Dae-Sik;Choi, Jin-Yong
    • Journal of Korean Society of Rural Planning
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    • v.6 no.1 s.11
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    • pp.44-49
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    • 2000
  • The purpose of this study is to develop a rural stream environment management system (RUSEMS) using Object Oriented Programming (OOP). In this study, the management goals of RUSEMS were conceptualized and systemized. The objects which required in RUSEMS were developed, then the method and the attribute of the objects were also devised, and the hierarchy of the objects was constructed by OMT method in this study. The results of the system application showed that RUSEMS was enable to manage, to analyze, and to offer the information about the monitoring, analyzing of the rural stream pollution, and managing pollution source of the watershed and the rural stream environment management for the friendly water space.

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