• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2014.05a
• /
• pp.280-281
• /
• 2014

Recently, it is certain that the increase of heating and cooling energy consumption by radical change in climate condition has caused serious problems related to environmental and energy concerns associated with increase of fossil fuel usage and carbon dioxide production as well as global warming. Therefore, various actions to reduce greenhouse gas and energy consumption have been prepared by world developed countries. The energy consumption by buildings approximately reaches 25% of total korea energy consumption. The greatest part in the buildings of the energy consumption is building facade. But a few research projects on concrete comprising more than 70% of outsider of buildings has been tried. This research is structural insulation concrete what improved insulation performance using micro form admixture and calcined diatomite powder and lightweight aggregate.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2013.11a
• /
• pp.40-41
• /
• 2013

The energy consumption by buildings approximately reaches 25% of total korea energy consumption. The greatest part in the buildings of the energy consumption is building facade. but a few research projects on concrete compising more than 70% of outsider of buildings has been tried. This research is structural insulation concrete what improved insulation performance using micro form admixture and calcined diatomite powedr and lightweight aggregate.

• Geophysics and Geophysical Exploration
• /
• v.10 no.3
• /
• pp.203-210
• /
• 2007

As a part of basic studies on monitoring of landslides and slope stability using SP measurements, micro-electric potentials of rock samples were measured accompanied with the rock failure by a uniaxial loading test were measured. The measurement system consists of a 8 channel A/D converter with 24 bit resolution, uniaxial loading tester, strain gages and 4 sets of electrode attached to a rock sample. Rock samples of granite, limestone, and sandstone were tested. Also, mortar samples were tested in order to monitor electric-potentials of a uniform sample. Micro-electric potentials were detected in all saturated samples and the strength of them increased as the loading force increased. Sandstone samples showed the largest strength of micro-electric potential and it followed limestone and granite samples, which indicates a positive relationship with porosity of rocks. The mechanism generating these micro-electric potential can be explained in terms of electro-kinetics. In case of dry samples, micro-electric potential could be observed only in sandstone samples, where piezoelectric effect played main role due to high contents of quartz in sandstone samples. We found that biggest micro-electric potentials were observed at the electrodes near the crack surface of rock samples. This is very encouraging result that SP monitoring can be applied to predicting landsliding or to estimate collapsing position combining with monitoring of acoustic emissions.

• The KIPS Transactions:PartC
• /
• v.9C no.1
• /
• pp.97-106
• /
• 2002

In 3GPP2 standard, MIP is used and a PDSN performs the function of FA to support macro mobility. When a MS is roaming from a PDSN area to another, the mobility supported is called macro mobility, while it is called micro mobility when a MS is roaming from a RN area to another in a PDSN area. Since a PDSN performs the function of FA in 3GPP2 standard, it is possible to support mobility but its mechanism is actually for supporting macro mobility, not for micro mobility, thus it is weak in processing fast and seamless handoff to support micro mobility. In this paper, we suggest the seamless handoff algorithm barred on multicast group mechanism to support micro mobility. Depending on the moving direction and velocity of a MS, the suggested algorithm constructs a multicast group of RNs on the forecasted MS's moving path, and maximally delays RNs'joining to a multicast group to increase the network efficiency. Moreover, to resolve the buffer overhead problem of the existent multicast scheme, the algorithm suggests that each RN buffers data only after the forecasted handoff time. To prove deadlock freeness and liveness of the algorithm. we use state transition diagrams, a Petri-net modeling and its reachability tree. Then, we evaluate the performance by simulation.

• 제어로봇시스템학회:학술대회논문집
• /
• 1988.10b
• /
• pp.858-863
• /
• 1988

A micro-processor based control system for a brushless DC motor used in the motor-driven electromechanical total artificial heart was developed. Functionally, the control system is composed of two parts. The first part is the velocity and position controller to assure that the motor follows a predetermined optimal velocity profile with minimal energy consumption, and to guarantee the full stroke length. This part also utilize the passive adaptive control method to be robust against the load disturbance, system parameter variation, and uncertainty which is the environment of artificial heart system. The pump output control is the second part, and this part provides the required responses of the artificial heart to the time-varying physiologic demands. The basic requirements of these responses are preload sensitivity, afterload insensitivity, and the balanced ventricular outputs. The performance and reliability of this control system was evaluated through a series of mock circulation tests and animal implantation, and the results are very encouraging.

• Journal of Advanced Marine Engineering and Technology
• /
• v.24 no.4
• /
• pp.460-469
• /
• 2000

A study on the corrosion behavior of RE36 steel for marine structure was investigated with parameters such as micro-Vickers hardness, corrosion potential and corrosion current density measurement of weld metal(WM), base metal (BM) and heat affected zone(HAZ), Al anode generating current and Al anode weight loss quantity in case of cathodic protection. And we carried out slow strain rate test(SSRT) in order to research mechanical properties such as stress at maximum load, percent strain, time to fracture and strain to failure ratio etc and to find out limiting cathodic polarization potential for hydrogen embrittlement with applied cathodic polarization potential. Hardness of HAZ part was the highest among those three parts and also galvanic corrosion susceptibility was the highest in HAZ part among those three parts due to the lowest corrosion potential than other parts. However corrosion current density was the highest in WM part among those three parts. And the optimum cathodic polarization potential showing the best mechanical properties obtained by SSRT method with applied constant cathodic potential was from - 770mV to - 875mV(SCE). However it is suggested that limiting cathodic polarization potential indicating hydrogen embrittlement on the mechanical properties was under - 900mV(SCE).

• Journal of Biosystems Engineering
• /
• v.30 no.5 s.112
• /
• pp.306-311
• /
• 2005

In this study, a biosensor was developed to rapidly diagnose the swine sarcoptic mange (Sarcoptes scabies var. suis). The ELISA was modified to reduce the processing time for rapid diagnosis. The biosensor consists of a biological reaction part, and a measurement and control part. The biological reaction part was designed for using micro-pumps and valves for fluid transportation, and the measurement control part composed of a photodiode, a light-emitting diode fur light measurement, and a microcomputer to implement assay A polystyrene covet was used as a reaction chamber. Signal output was read as the rate of change in optical density at 645nm. Eighteen pigs diagnosed with sacroptic mange and 19 control pigs were tested. Fifteen sacbies-infested pigs showed positive results ($83.3\%$ sensitivity). Sixteen control pigs showed negative results ($84.2\%$ specificity). The system could execute a diagnosis cycle in about 45 min. The results suggest that this biosensor is useful for the rapid diagnosis of swine sacroptic mange.

• Journal of the Korea Institute of Building Construction
• /
• v.16 no.1
• /
• pp.9-15
• /
• 2016

The part of a building with the biggest energy loss is the exterior and many studies are actively conducted to reduce the energy loss on that part. However, most studies consider the window frames and insulation materials, but many studies do not discuss the concrete that takes more than 70% of the exterior. In order to minimize the energy loss of buildings, it is necessary to enhance the concrete's insulation performance and studies need to be conducted on this. Therefore, this study used a micro foam cell admixture, calcined diatomite powder, and lightweight aggregates as a part of a study to develop a type of concrete with improved insulation performance that has twice higher thermal conductivity compared to concrete. It particularly secured the porosity inside concrete to lower thermal conductivity. As a result of the experiment, the slump and air capacity showed fair results, but all mixtures containing micro foaming agent showed 14.3~35.1% lower mass per unit of volume compared to regular concrete. Compressive strength decreased slightly due to the materials used to improve the insulating performance, but it all satisfied this study's target strength(24MPa). Thermal conductivity was up to twice higher than that of regular concrete.

• Journal of the Microelectronics and Packaging Society
• /
• v.17 no.4
• /
• pp.73-76
• /
• 2010

A two-facet approach was used to investigate the parametric performance of functional high-speed DDR3 (Double Data Rate) DRAM (Dynamic Random Access Memory) die placed in different types of BGA (Ball Grid Array) packages: wire-bonded BGA (FBGA, Fine Ball Grid Array), flip-chip (FCBGA) and lead-bonded $microBGA^{(R)}$. In the first section, packaged live DDR3 die were tested using automatic test equipment using high-resolution shmoo plots. It was found that the best timing and voltage margin was obtained using the lead-bonded microBGA, followed by the wire-bonded FBGA with the FCBGA exhibiting the worst performance of the three types tested. In particular the flip-chip packaged devices exhibited reduced operating voltage margin. In the second part of this work a test system was designed and constructed to mimic the electrical environment of the data bus in a PC's CPU-Memory subsystem that used a single DIMM (Dual In Line Memory Module) socket in point-to-point and point-to-two-point configurations. The emulation system was used to examine signal integrity for system-level operation at speeds in excess of 6 Gb/pin/sec in order to assess the frequency extensibility of the signal-carrying path of the microBGA considered for future high-speed DRAM packaging. The analyzed signal path was driven from either end of the data bus by a GaAs laser driver capable of operation beyond 10 GHz. Eye diagrams were measured using a high speed sampling oscilloscope with a pulse generator providing a pseudo-random bit sequence stimulus for the laser drivers. The memory controller was emulated using a circuit implemented on a BGA interposer employing the laser driver while the active DRAM was modeled using the same type of laser driver mounted to the DIMM module. A custom silicon loading die was designed and fabricated and placed into the microBGA packages that were attached to an instrumented DIMM module. It was found that 6.6 Gb/sec/pin operation appears feasible in both point to point and point to two point configurations when the input capacitance is limited to 2pF.

• Journal of Advanced Marine Engineering and Technology
• /
• v.33 no.1
• /
• pp.104-111
• /
• 2009

This paper shows the behaviors of macro- and micro-structures and mechanical properties for specimen's welding region welded by FSW. according to welding conditions with 5mm thickness aluminum 5083O alloy plate. It apparently results in defect-free weld zone in case traverse speed was changed to 32 mm/min under conditions of anti-clockwise direction and tool rotation speed such as 800 and 1250 rpm with tool's pin diameter of 5 ${\Phi}mm$ and shoulder diameter of 20 ${\Phi}mm$, pin length of 4.5 mm and tilting angle of $2^{\circ}$. The ultimate stress of ${\sigma}_T=331$ MPa and the yield point of 147 MPa are obtained at the condition of the travel speed of 32 mm/min with the tool rotation speed of 1250 rpm. There is neither voids nor cracks on bended surface of $180^{\circ}$ after bending test. The improvement of toughness after impact test was found. The lower rotating and traverse speed became, the higher were yield point, maximum stress and elongation(%) with the stresses and the elongation(%) versus the traverse speed diagram. Vickers hardness for cross section of welding zone were also presented. The typical macro-structures such as dynamically recrystallized zone, thermo-mechanically affected zone and heat affected zone and the micro-structures of the transverse cross-section were also showed. However, the author found out that the region of 6mm far away from shoulder circumference was affected by friction heat comprehensively, that is, hardness softened and that part of micro-structures were re-solid-solution or recrystallized, the author also knew that there is no mechanically deformation on heat affected zone but there are the flow of plastic deformation of $45^{\circ}$ direction on thermo-mechanically affected zone and the segregation of Al-Mg on nugget. The solid solution wt(%) of parent material as compared against of friction stir welded zone was comprehensively changed.