• Journal of Wetlands Research
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• v.23 no.2
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• pp.122-132
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• 2021

We reviewed the methods employed in Korean tidal flat surveys to measure the local abundance of the endangered wildlife and marine protected species, the fiddler crab, Austruca lactea. A complete census for infinite population is impossible even in a limited habitat within a tidal flat, and density estimates from samples strongly vary due to diverse biological and ecological factors. The habitat boundaries and areas shift with periodicities or rhythmic activities of organisms as well as measurement errors. Hence the local abundance calculated from density and habitat areas should be regarded as transient. This conjecture was valid based on the spatio-temporal variations of the density averages, standard error ranges, and spatial distribution of the crab, A. lactea observed for 3 years (2015-2017) in Songdo tidal flat in Incheon. We proposed the potential habitat areas using the occurrence probability of 50% from logistic regression model, reflecting the importance of habitat conservation value as an alternative to local abundance. The spatial shape of potential habitat predicted from a generalized model would remain constant over time unless the species' critical environmental conditions change rapidly. The species-specific model is expected to be used for the introduction of desired species in future habitat restoration/creation projects.

• Journal of Mechanical Science and Technology
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• v.16 no.11
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• pp.1550-1557
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• 2002

Diode laser sensor for measuring gas temperature and species concentration in combustion chamber was developed using 2.0 tim distributed feed back lasers. To evaluate the measurement sensitivity of diode laser sensor system, CO2 survey spectra near 2.0 Um were measured and compared with the calculated one. This diode laser absorption sensor was applied to measure gas temperatures in a premixed flat flame of CH$_4$-air mixture. Experimental results were in good agreement with the values by an R-type thermocouple within 6.12%. In addition, successful demonstration of measurement of gas temperature and species concentration in a soot flame showed the promising possibility of diode laser absorption sensors for practical combustion system with non-intrusive method.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.30A no.7
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• pp.75-81
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• 1993

In this paper, New type of Static Edge Triggered D Flip-Flop Circuits which are effective for the sequencial selecting and addressing of Matrix type Electrodes being applied to Flat Display Devices is proposed by the Design Technique using the Transmission Characteristics of Feedback Transistors and Charge Back Up Function. These Circuits composed of 2-4 less transistors in number than Conventional Static D Flip Flop's have some advantages that the Maximum Transition Time of Clock Signals allowed is increased by 100-450 times more than that of the Conventional circuit at 100KHz Clock Frequence and Circuit Safety is much increased by making the wider ranges, 1-4V, of Clock Levelas a Non-operating periods than 3-3.2V ranges in case of the Conventional Circuit at 10MHz clock frequence. By these advantages, These circuits can be very effectively used in case that clock signal has long transition time, especially on the low frequency operation.

• Transactions of Materials Processing
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• v.11 no.2
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• pp.147-154
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• 2002

The tension levelling Process is Performed to elongate the strip plastically In combination of tensile and bending strain so that all longitudinal fibers In the strip have an approximately equal amount ofn length and undesirable strip shapes are corrected to the flat shape. Thus paper is concerned with a simulation of the tension levelling process based on the analysis of tile unit model for the tension leveller. Analysis technique such as the sequential analysis of the unit model is suggested and verified with the assembly analysis of the unit model for the effective arts economic analysis of the full set of the tension leveller. Analysis of the full tension levelling Process using sequential unit models Is carried out for steel strips with the shape defect and provides the effect of the intermesh and optimum amount of the intermesh in tension levelling process.

• Geotechnical Engineering
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• v.9 no.1
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• pp.69-78
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• 1993

The Coulomb and Rankine theories have been usually used for design of retaining walls, in which the earth pressures have been assumed as a triangular distribution For the rigid retaining w리1 with inclined bacuace and horizontal surface backfilled by cohesionless soils, the analytical method of earth pressure distribution has been newly suggested by using the concept of the flat arch. The active thrust obtained by this method agrees well with those by the existing theories, except the Rankine solution. The analyzed results show that the height to the center of pressure depends mainly on the inclination of the back wall and the wall friction, instead of 0.33H, where H is the wall height.

• Journal of Environmental Science International
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• v.18 no.8
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• pp.911-918
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• 2009

Electromagnetic interference (EMI) is defined as the interaction phenomena of electromagnetic waves scattered from a large structure or complex terrain. In this study, the propagation of linear wave is modeled with ray theory, direct simulation Monte Carlo (DSMC), and some classical theories on flat plates. The wave physics of reflection, refraction, and diffraction are simulated for the investigation of front and back scattering of the one-dimensional plane wave from a tower with ray theory and DSMC, respectively. The effect of rotating disk idealized from the real wind-turbine blades is modeled with a simplified version of the classical electromagnetic theory as well as DSMC based on the ray theory.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.20 no.2
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• pp.106-112
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• 2007

Advanced back-end processing requires the integration of low-k dielectrics and Cu. However, in the presence of an electric field and a temperature, positive Cu ions may drift rapidly through dielectric and causing reliability problems. Therefore, in this paper, Cu+ drift diffusion in two low-k materials and silicon oxide is evaluated. The drift diffusion is investigated by measuring shifts in the flat band voltage of capacitance-voltage measurements on Cu gate capacitors after bias thermal stressing. The Cu+ drift late in $SiO_{x}C_{y}\;(2.85{\pm}0.03)$ and Polyimide(2.7${\leq}k{\leq}3.0$) is Considerably lower than in thermal oxide.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2001.05a
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• pp.201-204
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• 2001

The tension levelling process is performed to elongate the strip plastically in combination of tensile and bending strain so that all longitudinal fibers in the strip have an approximately equal amount of length and undesirable strip shapes are corrected to the flat shape. This paper is concerned with a simulation of the tension levelling process based on the analysis of the unit model for the tension leveller. Analysis technique such as the sequential analysis of the nit model is suggested and verified with the assembly analysis of the unit model for the effective and economic analysis of the full set of the tension leveller. Analysis of the full tension levelling process using sequential unit models is carried out and provides the effect of the intermesh and optimum amount of the intermesh in tension levelling process.

• Proceedings of the IEEK Conference
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• 2002.07c
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• pp.1398-1400
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• 2002

A new PLF-BLU (Plastic Light Fiber-Back Light Unit) using side glowing light fiber rods array for the 42" LCD TV display has been evelopedd. The light fibers were 14mm in diameter and 50cm long pure transparent acrylic rods of 1.49 refractive index. Fine seratees were made on the flat side of rod. extremely bright incandscent light from lamp fed into the fiber si scattered at scratches then emerges through the surface of rod. A typical PLF-BLU system consists of 24 PLFs produced side glow of brightness of 4,500cd/㎡ to 6,500cd/㎡. New PLF-BLU is proved to be a BLU of rigid, bright, no heat generation, and low power consumption, hence a prospective BLU system for very and/or ultra large size TVs. A new LED-PLF-BLU system considered to be a revolutionary to break-through of the BLU technologies has also been developed, and is decribed briefly.

• ETRI Journal
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• v.26 no.5
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• pp.443-451
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• 2004

Since the publication of Alamouti's famous space-time block code, various quasi-orthogonal space-time block codes (QSTBC) for multi-input multi-output (MIMO) fading channels for more than two transmit antennas have been proposed. It has been shown that these codes cannot achieve full diversity at full rate. In this paper, we present a simple feedback scheme for rich scattering (flat Rayleigh fading) MIMO channels that improves the coding gain and diversity of a QSTBC for 2$^n$ (n=3, 4, ${\cdots}$) transmit antennas. The relevant channel state information is sent back from the receiver to the transmitter quantized to one or two bits per code block. In this way, signal transmission with an improved coding gain and diversity near to the maximum diversity order is achieved. Such high diversity can be exploited with either a maximum-likelihood receiver or low-complexity zero-forcing receiver.