• Structural Engineering and Mechanics
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• 제58권6호
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• pp.967-988
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• 2016

Due to the significant aerodynamic interference from sub-towers and surrounding tall buildings, the wind loads and dynamic responses on main tower of three-tower connected tall building typically change especially compared with those on the isolated single tall building. This paper addresses the wind load effects and equivalent static wind loads (ESWLs) of three-tower connected tall building based on measured synchronous surface pressures in a wind tunnel. The variations of the global shape coefficients and extremum wind loads of main tower structure with or without interference effect under different wind directions are studied, pointing out the deficiency of the traditional wind loads based on the load codes for the three-tower connected tall building. The ESWLs calculation method based on elastic restoring forces is proposed, which completely contains the quasi-static item, inertia item and the coupled effect between them. Then the wind-induced displacement and acceleration responses for main tower of three-tower connected tall building in the horizontal and torsional directions are investigated, subsequently the structural basal and floor ESWLs under different return periods, wind directions and damping ratios are studied. Finally, the action mechanism of interference effect on structural wind effects is investigated. Main conclusions can provide a sientific basis for the wind-resistant design of such three-tower connected tall building.

• Structural Engineering and Mechanics
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• 제34권6호
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• pp.739-753
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• 2010

Pointing to the design requirement of prestressed space grid structure being the target cable force, the pretension scheme decision analysis method is studied when there's great difference between structural actual state and the analytical model. Based on recursive formulation of cable forces, the simulative recursive system for pretension process is established from the systematic viewpoint, including four kinds of parameters, i.e., system initial value (structural initial state), system input value (tensioning control force scheme), system state parameters (influence matrix of cable forces), system output value (pretension accomplishment). The system controllability depends on the system state parameters. Based on cable force observation values, the influence matrix for system state parameters can be calculated, making the system controllable. Next, the pretension scheme decision method based on cable force observation values can be formed on the basis of iterative calculation for recursive system. In this way, the tensioning control force scheme that can meet the design requirement when next cyclic supplemental tension finished is obtained. Engineering example analysis results show that the proposed method in this paper can reduce a lot of cyclic tensioning work and meanwhile the design requirement can be met.

• 항공우주시스템공학회지
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• 제10권2호
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• pp.1-6
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• 2016

The thermal analysis of electronic equipment is required to predict the reliability of electronic equipment being loaded on a satellite. The transient heat transfer of electronic equipment that was developed recently has been generated using a large-scale integration circuit. If there is a transient heat transfer between EEE(Electric, Electronic and Electro mechanical) parts, it may lead to failure the satellite mission. In this study, we performed the thermal design and analysis for reliability of APD(Antenna Pointing Driver) electronics for activation of a spaceborne X-band 2-axis antenna. The EEE parts were designed using a thermal mathematical model without the thermal mitigation element. In addition, thermal analysis was performed based on the worst case for verifying the reliability of EEE parts. For the thermal analysis results, the thermal stability of electronic equipment has been demonstrated by satisfying the de-rating junction temperature.

• 한국소음진동공학회논문집
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• 제21권5호
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• pp.408-415
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• 2011

Advanced tanks in the future combat system are expected to have the trends of large caliber, high explosive shell and light weight for destructive power and improvement in mobility. Their guns are required to have longer barrels to meet increased muzzle exit velocities. However, as the length of the barrel is extended, the vibrations induced by the breech forces in fire and the terrain lead to increased muzzle pointing errors. Therefore, the fire-induced and terrain-induced vibrations must be attenuated. A method to reduce these vibrations without the significant increase of the gun mass is to use the forward thermal shroud as part of a tuned mass damper. In this study, the dynamically-tuned-shroud using this shroud and leaf springs is introduced and its effectiveness on the vibration attenuations of the barrel are verified. The parametric studies on the stiffness of these leaf springs are performed and the analytical results are verified using the experimental model of the dynamically-tuned-shroud.

• 한국환경과학회:학술대회논문집
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• 한국환경과학회 2003년도 International Symposium on Clean Environment
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• pp.192-197
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• 2003

The purpose of this study is to present the conditions and methods for keeping the sustainability of the landscape resources of the East Coast of Gangwon province, the republic of Korea by investigating the landscape resources management in the area and pointing out its problems. The problems of the landscape resources management are： 1) the disturbance of the persistence of life by reclamation, the population reduction in the ecosystem due to the overload in environmental capacity, and the severance of space between land and water. 2) the reduction of the benefits from indirect experience by interfering with the conservation of fluxes -- the manipulation of horizontal arrangement of the landscape resource, the visual disturbance by the construction of high-storied buildings, and the disharmony between the color/image and the environment. The means for keeping sustainability of the landscape resources include the regulations of development and use, the change in the recognition of the value of landscape resources and the moral system, and the improvement of resource management skills.

• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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• 제1권2호
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• pp.137-144
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• 1997

Flocculation-spectrophotometry and streaming current detector(SCD) method were investigated and compared in order to determine the optimum dosages of synthetic cationic polymers of different charge density and molecular mass for the removal of humic acid. The optimum dosage for each of the polymers was determined with the dosage at which the lowest absorbance of humic acid was shown for the former and was determined with the dosage required during charge neutralization of humic acid for the latter. It was in good agreement between both methods and there is a strong inverse correlation between the optimum dosage and charge density of the polymers, with highly charged polymer giving the lowest optimum dosage, pointing out the importance the charge neutralization. By flocculation-spectrophotometry, it was found that the absorbance of humic acid with the amount of each of the polymers dosed, changes sharply for polymers of high charge density, but changes rather broadly for polymers of low and middle charge density. Both methods showed that a stoichiometric correlation exists between the optimum dosage of each of the cationic polymers and the negatively charged humic acid.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 제39회 하계학술대회
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• pp.1488-1490
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• 2008

The gyroscope is the sensor for detecting the rotation in inertial reference frame and constitute the navigation system together an accelerometer. As the inertial reference equipment for attitude determination and control in the satellite, the mechanical gyroscope has been used but it bring the disturbance for mass unbalance so the disturbance give a bad influence to the observation satellite mission because the mechanical gyroscope has the rotation parts. During the launch, The mechanical gyroscope is weak in vibration, shock and has the defect of narrow operating temperature range so it need the special design in integration. Recently the low orbit observation satellite for seeking the high pointing accuracy of image camera payload accept the FOG(Fiber Optic Gyro) or RLG(Ring Laser Gyro) for the attitude determination and control. The Ring Laser Gyro makes use of the Sanac effect within a resonant ring cavity of a He-Ne laser and has more accuracy than the other gyros. It need the 1000V DC to create the He-Ne plasma in discharge tube. In this paper, the design process of the High Voltage Power Supply for RLG(Ring Laser Gyroscope) is described. The specification for High Voltage Power Supply(HVPS) is proposed. Also, The analysis of flyback converter topology is explained. The Design for the HVPS is composed of the inverter circuit, feedback control circuit, high frequency switching transformer design and voltage doubler circuit.

• Architectural research
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• 제13권1호
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• pp.11-16
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• 2011

This article illuminates the relationship between the human being and the surrounding things by referring to the philosophy of Martin Heidegger and Maurice Merleau-Ponty. Criticizing our habitual approaches to apprehending 'what a thing is,' the two thinkers elucidate how 'what a thing is' can be understood only in conjunction with situations in the everyday and how humanity is joined with the qualities of the thing. In addition to the situated-ness of a thing, this article demonstrates the situated-ness of the human being, too, by referring to the notion of the horizon in the tradition of phenomenology. The last part of the paper discusses the basic premises of sustainability in reference to the situated-ness of both things and human beings. Framing natural things such as light as the alternative sources of energy propagandized in sustainability seems progressive. However, this attitude maintains fundamentally the same instrumental attitude we had towards nature, an attitude that has caused the current ecological crisis. By pointing this out, this article seeks to shape a ground for a broad spectrum of sustainability that embraces non-instrumental dimensions such as the practical, the ethical and the spiritual. This article also points out the limits of some of the currently available versions of ecology such as Shallow Ecology and Deep Ecology. In so doing, it seeks to lay out the parameters that any future version of sustainability and ecology needs to address.

• Journal of mucopolysaccharidosis and rare diseases
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• 제2권1호
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• pp.8-12
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• 2016

Mucolipidosis (ML) is a kind of skeletal dysplasia. Characteristic X-ray findings of the bone may contribute to the early diagnosis and treatment of ML II/III. Skeletal radiographs show distinctive patterns at different ages: neonatal hyperparathyroidism, osteodystrophy (similar to chronic osteitis fibrosa cystica), and dysostosis multiplex. Patients with ML II/III show a mixture of osteodystrophic bone changes and atypical changes of dysostosis multiplex: proximal pointing of the metacarpals in the wrist, dysplastic changes in the lower third of the ilia, marked broadening of the ribs becoming oar-shaped, and beaking of the lower thoracic and lumbar vertebrae. In ML II, the osteodystrophy has clinical and radiographic features of neonatal hyperparathyroidism. In some neonatal subjects, chemical hyperparathyroidism is also demonstrated. After transient hyperparathyroidism in newborns, the progressive osteitis fibrosa cystica develops from 3-6 months of age. Patients with ML III show prominent skeletal involvement, particularly the destruction of vertebral bodies and the femoral heads. Intravenous pamidronate treatment is well tolerated, and it can produce clinical effects, with a reduction in bone pain and improvements in mobility in patients with ML III. In this review, the skeletal manifestations of ML II and III are investigated.

• 한국방송∙미디어공학회:학술대회논문집
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• 한국방송공학회 2009년도 IWAIT
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• pp.742-745
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• 2009

This paper proposes a wireless LAN antenna system that tracks an object automatically by using image-based tracking. The proposed system consists of a camera and a pan-tilt unit in addition to a directional wireless LAN antenna. The camera and the directional antenna are set in same direction and they are set on the pan-tilt unit. A target object which has a wireless LAN receiver is tracked by using images captured by the camera. And the directional antenna faces in same direction as the camera by the pan-tilt unit. Therefore, the directional antenna keeps pointing the receiver, and a transmitting efficiency is improved. A result of a fundamental experiment shows that a receiver attached to a flying airship was tracked by a prototype of the proposed antenna system. The airship flied about, and the proposed antenna system was set on a roof of a building. The experimental result indicates an effectiveness of the proposed system compared to the conventional directional LAN antenna.