• Title/Summary/Keyword: impact forces

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Analysis and implications on Ukrainian Military Intelligence Team's Decapitation Operation (우크라이나 군사정보팀의(Military Intelligence Team) 핀셋작전 분석과 시사점)

  • Cho, Sang Keun;Zhytko, Andrii;Park, Sung Jun;Kwon, Bum June;Seo, Kanh ll;Park, Sang-Hyuk
    • The Journal of the Convergence on Culture Technology
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    • v.8 no.6
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    • pp.435-439
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    • 2022
  • ROK has a lot to benchmark from how Ukraine is fighting Russia back with its tactical wins. They have taken a targeted strategy to strike Russia's top generals with high precision. To carry out this strategy, Ukraine is operating a Special Operations Force, which utilizes US/NATO forces, civilian and own resources for maximum impact. Of note, they utilize Starlink for seamless connection from detection, decision-making to strike to maximize operational efficiency. As ROK faces security threat of weapons of mass destruction, Ukraine's military intelligence organization set-up, weapons system and operations can provide some guidance on how to leverage its various SOF as well.

PRC Maritime Operational Capability and the Task for the ROK Military (중국군의 해양작전능력과 한국군의 과제)

  • Kim, Min-Seok
    • Strategy21
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    • s.33
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    • pp.65-112
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    • 2014
  • Recent trends show that the PRC has stepped aside its "army-centered approach" and placed greater emphasis on its Navy and Air Force for a wider range of operations, thereby reducing its ground force and harnessing its economic power and military technology into naval development. A quantitative growth of the PLA Navy itself is no surprise as this is not a recent phenomenon. Now is the time to pay closer attention to the level of PRC naval force's performance and the extent of its warfighting capacity in the maritime domain. It is also worth asking what China can do with its widening naval power foundation. In short, it is time to delve into several possible scenarios I which the PRC poses a real threat. With this in mind, in Section Two the paper seeks to observe the construction progress of PRC's naval power and its future prospects up to the year 2020, and categorize time frame according to its major force improvement trends. By analyzing qualitative improvements made over time, such as the scale of investment and the number of ships compared to increase in displacement (tonnage), this paper attempts to identify salient features in the construction of naval power. Chapter Three sets out performance evaluation on each type of PRC naval ships as well as capabilities of the Navy, Air Force, the Second Artillery (i.e., strategic missile forces) and satellites that could support maritime warfare. Finall, the concluding chapter estimates the PRC's maritime warfighting capability as anticipated in respective conflict scenarios, and considers its impact on the Korean Peninsula and proposes the directions ROK should steer in response. First of all, since the 1980s the PRC navy has undergone transitions as the focus of its military strategic outlook shifted from ground warfare to maritime warfare, and within 30 years of its effort to construct naval power while greatly reducing the size of its ground forces, the PRC has succeeded in building its naval power next to the U.S.'s in the world in terms of number, with acquisition of an aircraft carrier, Chinese-version of the Aegis, submarines and so on. The PRC also enjoys great potentials to qualitatively develop its forces such as indigenous aircraft carriers, next-generation strategic submarines, next-generation destroyers and so forth, which is possible because the PRC has accumulated its independent production capabilities in the process of its 30-year-long efforts. Secondly, one could argue that ROK still has its chances of coping with the PRC in naval power since, despite its continuous efforts, many estimate that the PRC naval force is roughly ten or more years behind that of superpowers such as the U.S., on areas including radar detection capability, EW capability, C4I and data-link systems, doctrines on force employment as well as tactics, and such gap cannot be easily overcome. The most probable scenarios involving the PRC in sea areas surrounding the Korean Peninsula are: first, upon the outbreak of war in the peninsula, the PRC may pursue military intervention through sea, thereby undermining efforts of the ROK-U.S. combined operations; second, ROK-PRC or PRC-Japan conflicts over maritime jurisdiction or ownership over the Senkaku/Diaoyu islands could inflict damage to ROK territorial sovereignty or economic gains. The PRC would likely attempt to resolve the conflict employing blitzkrieg tactics before U.S. forces arrive on the scene, while at the same time delaying and denying access of the incoming U.S. forces. If this proves unattainable, the PRC could take a course of action adopting "long-term attrition warfare," thus weakening its enemy's sustainability. All in all, thiss paper makes three proposals on how the ROK should respond. First, modern warfare as well as the emergent future warfare demonstrates that the center stage of battle is no longer the domestic territory, but rather further away into the sea and space. In this respect, the ROKN should take advantage of the distinct feature of battle space on the peninsula, which is surrounded by the seas, and obtain capabilities to intercept more than 50 percent of the enemy's ballistic missiles, including those of North Korea. In tandem with this capacity, employment of a large scale of UAV/F Carrier for Kill Chain operations should enhance effectiveness. This is because conditions are more favorable to defend from sea, on matters concerning accuracy rates against enemy targets, minimized threat of friendly damage, and cost effectiveness. Second, to maintain readiness for a North Korean crisis where timely deployment of US forces is not possible, the ROKN ought to obtain capabilities to hold the enemy attack at bay while deterring PRC naval intervention. It is also argued that ROKN should strengthen its power so as to protect national interests in the seas surrounding the peninsula without support from the USN, should ROK-PRC or ROK-Japan conflict arise concerning maritime jurisprudence. Third, the ROK should fortify infrastructures for independent construction of naval power and expand its R&D efforts, and for this purpose, the ROK should make the most of the advantages stemming from the ROK-U.S. alliance inducing active support from the United States. The rationale behind this argument is that while it is strategically effective to rely on alliance or jump on the bandwagon, the ultimate goal is always to acquire an independent response capability as much as possible.

Seismic Behaviour of Exterior Joints in Post-Tensioned Flat Plate Systems (포스트 텐션 플랫 플레이트 외부 접합부의 내진 거동)

  • Han, Sang-Whan;Kee, Seong-Hoon;Kang, Tomas H.K.;Cho, Jong;Lee, Li-Hyung
    • Journal of the Korea Concrete Institute
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    • v.18 no.5 s.95
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    • pp.595-602
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    • 2006
  • An experimental study was conducted to investigate seismic behaviour of post-tensioned(PT) exterior slab-column connections used for the purpose to resist gravity loads only. For these, 2/3-scale, two PT post-tensioned exterior connections with two different tendon arrangement patterns and one conventional reinforced concrete(RC) exterior connection was tested under quasi-static, uni-directional reversed cyclic loading. During the lateral testing, gravity forces transferred to the column were kept constant to closely simulate a moment to shear ratio of a real building. One of the objectives of this study was to assess the necessity and/or the quantity of bottom bonded reinforcement needed to resist moment reversal which would occur under significant inelastic deformations of the adjacent lateral force resisting systems. The ACI 318 and 352 provisions for structural integrity were applied to provide the bottom reinforcement passing through the column for the specimens. Prior test results were also collected to conduct comparative studies for some design parameters such as the tendon arrangement pattern, the effect of post-tensioning forces and the use of bottom bonded reinforcement. Consequently, the impact of tendon arrangement on the seismic performance of the PT connection, that is lateral drift capacity and ductility, dissipated energy and failure mechanism, was considerable. Moreover, test results showed that the amount of bottom reinforcement specified by ACI 352. 1R-89 was sufficient for resisting positive moments arising from moment reversal under reversed cyclic loads. Shear strength of the tested specimens was more accurately predicted by the shear strength equation(ACI 318) considering the average compressive stress over the concrete($f_{pc}$) due to post-tensioning forces than that without considering $f_{pc}$.

Analysis of Kinetic Differences According to Ankle Taping Types in Drop Landing (드롭랜딩 시 발목테이핑 유형에 따른 운동역학적 차이 분석)

  • Lee, Kyung-Ill;Hong, Wan-Ki
    • Korean Journal of Applied Biomechanics
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    • v.24 no.1
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    • pp.51-57
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    • 2014
  • The purpose of this study was to compare and analyze kinetic variables of lower limbs according to types of ankle taping in drop landing. For this, targeting seven male basketball players (average age: $20.8{\pm}0.74yrs$, average height: $187.4{\pm}3.92cm$, average weight: $79.8{\pm}7.62kg$) with no instability of ankle joints, the drop landing motion was conducted according to three types of inelastic taping (C-type), elastic taping (K-type), and no treatment (N-taping). Based on the result, the next conclusion was reached. First, the effect of taping for the players with stable ankles was minimal and the high load on ankle joints offset the fixing effect of inelastic taping. Thus the inelastic taping for the players with stable ankles did not have an effect on the control of dorsal flexion during one-foot landing. Second, increasing angular velocity by increasing the movable range of knee joints disperses impact forces, yet inelastic taping restricted the range of knee joint motion and at the same time increased angular velocity, adding to a negative effect on knee joints. Third, inelastic taping induced inefficient motion of Lower limbs and unstable impact force control of ankle joints at the moment of landing and produced maximum vertical ground reaction force, which led to an increase of load. Therefore, inelastic ankle taping of players whose jump actions occur very often should be reconsidered. Also, it is thought that this study has a great meaning in proving the problem of inelastic taping related to knee pain with unknown causes.

Current situation and future prospects for beef production in Europe - A review

  • Hocquette, Jean-Francois;Ellies-Oury, Marie-Pierre;Lherm, Michel;Pineau, Christele;Deblitz, Claus;Farmer, Linda
    • Asian-Australasian Journal of Animal Sciences
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    • v.31 no.7
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    • pp.1017-1035
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    • 2018
  • The European Union (EU) is the world's third largest producer of beef. This contributes to the economy, rural development, social life, culture and gastronomy of Europe. The diversity of breeds, animal types (cows, bulls, steers, heifers) and farming systems (intensive, extensive on permanent or temporary pastures, mixed, breeders, feeders, etc) is a strength, and a weakness as the industry is often fragmented and poorly connected. There are also societal concerns regarding animal welfare and environmental issues, despite some positive environmental impacts of farming systems. The EU is amongst the most efficient for beef production as demonstrated by a relative low production of greenhouse gases. Due to regional differences in terms of climate, pasture availability, livestock practices and farms characteristics, productivity and incomes of beef producers vary widely across regions, being among the lowest of the agricultural systems. The beef industry is facing unprecedented challenges related to animal welfare, environmental impact, origin, authenticity, nutritional benefits and eating quality of beef. These may affect the whole industry, especially its farmers. It is therefore essential to bring the beef industry together to spread best practice and better exploit research to maintain and develop an economically viable and sustainable beef industry. Meeting consumers' expectations may be achieved by a better prediction of beef palatability using a modelling approach, such as in Australia. There is a need for accurate information and dissemination on the benefits and issues of beef for human health and for environmental impact. A better objective description of goods and services derived from livestock farming is also required. Putting into practice "agroecology" and organic farming principles are other potential avenues for the future. Different future scenarios can be written depending on the major driving forces, notably meat consumption, climate change, environmental policies and future organization of the supply chain.

An Analysis of Changing River Sections Using GIS Spatial Analysis - Nonsan River - (공간분석기법을 이용한 하천단면 변화분석 - 논산천을 대상으로 -)

  • Lee, Jae-Yil;Lee, Gyu-Sung;Ha, Sung-Ryong
    • Journal of Environmental Impact Assessment
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    • v.19 no.1
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    • pp.91-97
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    • 2010
  • The systematic data management system in the area of river flow analysis has not yet constructed, even though the need is evident due to the complicated process of tremendous input/output data in the modeling study and the importance of visualization of spatial flow variation. The objectives of this study are to suggest the method for analysis of changing river sections affecting ecological habitat characteristics. The effects of ecological habitat characteristics are assessed with respect to changing river sections. A GIS special analysis is created representing in the past section of Nonsan-river using historical data. Topographic surfaces are subject to erosional and depositional forces that a specific set of surface characteristics unique to elevation data. GIS spatial analyst is used to generate surface grids from historical point data. Using the GIS spatial analyst can be constructed sections for anywhere of river. The change of depth between 1979 and 1988, the left bank elevations of a river are increased about 1.5m. But the right bank elevations of a river are decreased about 2.3m caused by erosion. In addition, the change of spatial between 1988 and 2002, the regions of a river from upper stream to midstream are decreased the elevation. But the downstream regions are increased the elevation. These changes are analyzed in GIS program to assess methods for affecting ecological habitat.

Equivalent static wind loads analysis of tall television towers considering terrain factors of hilltops based on force measurement experiment

  • Ke, Shitang;Wang, Hao;Ge, Yaojun;Zhao, Lin;Cao, Shuyang
    • Structural Engineering and Mechanics
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    • v.63 no.4
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    • pp.509-519
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    • 2017
  • Wind field in mountainous regions demonstrates unique distribution characteristic as compared with the wind field of the flat area, wind load and wind effect are the key considerations in structural design of television towers situated in mountainous regions. The television tower to be constructed is located at the top of Xiushan Mountain in Nanjing, China. In order to investigate the impact of terrain factors of hilltops on wind loads, firstly a wind tunnel test was performed for the mountainous area within 800m from the television tower. Then the tower basal forces such as bending moments and shear strength were obtained based on high frequency force balance (HFFB) test. Based on the experiments, the improved method for determining the load combinations was applied to extract the response distribution patterns of foundation internal force and peak acceleration of the tower top, then the equivalent static wind loads were computed under different wind angles, load conditions and equivalent goals. The impact of terrain factors, damping ratio and equivalent goals on the wind load distribution of a television tower was discussed. Finally the equivalent static wind loads of the television tower under the 5 most adverse wind angles and 5 most adverse load conditions were computed. The experimental method, computations and research findings provide important references for the anti-wind design of high-rise structure built on hilltops.

Analysis and Evaluation of Reduction of Impact Force in a Coupler when a Long Freight Car Brakes (장대화물열차 제동 시 연결기에 발생하는 충격력 해석 및 분석)

  • Lee, Jeong Jun;Koo, Jeong Seo;Cho, Byung Jin;Na, Hee Seung;Mun, Hyung Seok
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.17 no.1
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    • pp.130-137
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    • 2018
  • In long freight trains, there is a brake time delay in the neighboring freight cars that causes damage and fractures of couplers, especially the knuckle of them. If there is a problem for couplers in the cars, this could cause a derailment and lead to damage of human life and property damage. In this study, maximum forces on the couplers are studied when a long freight car brakes, with brake delay time and coupler gap. We have made a dynamic model of 50 freight cars and couplers, applying contact between couplers and a characteristic curve for expressing force and displacement of buffers with SIMPACK, a multi-body dynamics program. We use EN 14531-2 from the British Standards Institution, a standard of freight car brakes for the verification of the dynamic model. We also use a simplified method to analyze the dynamic model of 50 freight cars. With changing coupler gap and brake delay time, we do comparative analysis with AAR M-201 from the Association of American Railroads, a standard of AAR couplers. From this result, we find that the standard on fatigue limit is satisfied, such that the brake delay time is within 0.06 second if the coupler gap of the AAR coupler is within 20 millimeters.

Estimation of Erositivity Using an Impact Disdrometer in East of Alagoas (충격 입자 분포 탐지기를 이용한 침식도 추정)

  • Tenorio, R.S.;Kwon, Byung Hyuk;Moraes, M.C. da S.;Yoon, Hong-Joo
    • The Journal of the Korea institute of electronic communication sciences
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    • v.15 no.2
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    • pp.371-378
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    • 2020
  • Rainfall is one of the most active forces that cause soil erosion. The action of rain on the soil exerts an erosive power caused by the impact of the drops, which fall with variable speed and kinetic energy, depending directly on the diameter of the drop. The objective of this study is to determine algorithms capable of estimating rainfall erosivity for the region of Maceió-AL. For this purpose, erosion rains were collected between 2003 and 2006 using a RD-69 disdrometer, which continuously and automatically measures rainfall distribution in a range of 1 min. The determination of algorithms in the form of power equation to estimate was adjusted with one and two independent variables (amount of rainfall, duration and maximum intensity).

Impact of spar-nacelle-blade coupling on the edgewise response of floating offshore wind turbines

  • Dinh, Van-Nguyen;Basu, Biswajit;Nielsen, Soren R.K.
    • Coupled systems mechanics
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    • v.2 no.3
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    • pp.231-253
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    • 2013
  • The impact of spar-nacelle-blade coupling on edgewise dynamic responses of spar-type floating wind turbines (S-FOWT) is investigated in this paper. Currently, this coupling is not considered explicitly by researchers. First of all, a coupled model of edgewise vibration of the S-FOWT considering the aerodynamic properties of the blade, variable mass and stiffness per unit length, gravity, the interactions among the blades, nacelle, spar and mooring system, the hydrodynamic effects, the restoring moment and the buoyancy force is proposed. The aerodynamic loads are combined of a steady wind (including the wind shear) and turbulence. Each blade is modeled as a cantilever beam vibrating in its fundamental mode. The mooring cables are modeled using an extended quasi-static method. The hydrodynamic effects calculated by using Morison's equation and strip theory consist of added mass, fluid inertia and viscous drag forces. The random sea state is simulated by superimposing a number of linear regular waves. The model shows that the vibration of the blades, nacelle, tower, and spar are coupled in all degrees of freedom and in all inertial, dissipative and elastic components. An uncoupled model of the S-FOWT is then formulated in which the blades and the nacelle are not coupled with the spar vibration. A 5MW S-FOWT is analyzed by using the two proposed models. In the no-wave sea, the coupling is found to contribute to spar responses only. When the wave loading is considered, the coupling is significant for the responses of both the nacelle and the spar.