• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.35 no.4
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• pp.269-280
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• 2017

Recently, in the United States, there has been short-term intensive rainfall due to El Ni?o and Rania. The Rim Fire was a wildland fire that was started in a remote canyon in Stanislaus National Forest in California. This portion of the central Sierra Nevada spans Tuolumne and Mariposa counties. This study is about estimating unsteady soil loss due to rainfall impact according to Rim Fire at California. It implies that caution needs to be taken in selecting the grid size for estimating soil loss using numerical modeling approach. Soil loss increased in all duration times before Rim fire. But it increased until 7 days and reduced or kept stable after that. Based on the 2014 average rainfall 1388 mm/yr, soil loss was estimated to be 247,518 ton/ha/yr before Rim Fire, and 9,389,937 ton/ha/yr after that.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.18 no.6
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• pp.779-792
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• 1993

In a switching node or an ATM multiplexer of the ATM network, a good bandwidth utilization can be achieved by the priority control using the 1-bit(Cell Loss priority) in ATM cell header. In this paper, the mixed mechanism is proposed to make up for shortcomings of existing space priority control mechanisms and to decrease the loss probability of high priority cell and its performance is analyzed about the cell loss probability. To estimate the performance of proposed mixed mechanism, its cell loss probability is compared with those of non-priority mechanism, push-out mechanism and partial buffer sharing mechanism. The cell loss probability is analyzed using a M/D/1/N modeling and a 2-state MMPP/D/1/N modeling and also comparison between two modelings is made. To verify this result of numerical analysis, the computer simulation is performed for each mechanism using the simulation language, SIMSRIPT II.5.

• International Journal of Concrete Structures and Materials
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• v.10 no.1
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• pp.1-13
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• 2016

The progressive collapse analysis of reinforced concrete (RC) moment-frame buildings under extreme loads is discussed from the perspective of modeling issues. A threat-independent approach or the alternate path method forms the basis of the simulations wherein the extreme event is modeled via column removal scenarios. Using a prototype RC frame building, issues and considerations in constitutive modeling of materials, options in modeling the structural elements and specification of gravity loads are discussed with the goal of achieving consistent models that can be used in collapse scenarios involving successive loss of load-bearing columns at the lowest level of the building. The role of the floor slabs in mobilizing catenary action and influencing the progressive collapse response is also highlighted. Finally, an energy-based approach for identifying the proximity to collapse of regular multi-story buildings is proposed.

• Journal of international Conference on Electrical Machines and Systems
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• v.1 no.1
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• pp.17-22
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• 2012

This paper presents analyzed results of a permanent magnet motor by using complex E&S modeling. The calculated results are compared with ones from the conventional E&S modeling for verification. Combinations of the numbers of slots and poles are investigated to reduce total iron loss. The results demonstrate that the complex E&S modeling is very useful in design under consideration of rotational magnetic field and magnetic anisotropy.

• Journal of Communications and Networks
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• v.5 no.4
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• pp.303-308
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• 2003

We present a statistical model for the path loss of ultrawideband (UWB) channels in indoor environments. In contrast to our previously reported measurements, the data reported here are for a bandwidth of 6GHz rather than 1.25GHz; they encompass commercial buildings in addition to single-family homes (20 of each); and local spatial averaging is included. As before, the center frequency is 5.0GHz. Separate models are given for commercial and residential environments and, within each category, for lineof sight (LOS) and non-line-of-sight (NLS) paths. All four models have the same mathematical structure, differing only in their numerical parameters. The two new models (LOS and NLS) for residences closely match those derived from the previous measurements, thus affirming the stability of our path loss modeling. We find, also, that the path loss statistics for the two categories of buildings are quite similar.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.824-828
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• 2007

In this paper Statistical Energy Analysis has been considered to predict middle, high frequency air borne interior noise. PIM method is used for verification. Damping loss factor and coupling loss factor have been derived from the response(SPL) of sub systems when the power is applied. The airborne SEA model of vehicle is modeled through AutoSea2. Insulation material's absorption coefficient and transmission loss are acquired from closed form solution and experiment.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.718_719
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• 2009

This paper deals with the loss analysis and efficiency evaluations in a synchronous reluctance motor (SynRM) using a coupled transient finite element method (FEM) and Preisach modeling, which is presented to analyze the characteristics under the effect of saturation and hysteresis loss. The focus of this paper is the efficiency evaluation relative to hysteresis loss, copper loss, etc. on the basis of speed, load condition in a SynRM. Computer simulation and experimental result for the efficiency using dynamometer show the propriety of the proposed method.

• ETRI Journal
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• v.44 no.2
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• pp.274-285
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• 2022

Retransmission in optical burst switching networks is a solution to recover data loss by retransmitting the dropped burst. The ingress node temporarily stores a copy of the complete burst and sends it each time it receives a retransmission request from the core node. Some retransmission schemes have been suggested, but uncontrolled retransmission often increases the network load, consumes more bandwidth, and consequently, increases the probability of contention. Controlled retransmission is therefore essential. This paper proposes a new controlled retransmission scheme for loss recovery, where the available bandwidth of wavelength channels and the burst lifetime are referred to as network conditions to determine whether to transmit a dropped burst. A retrial queue-based analysis model is also constructed to validate the proposed retransmission scheme. The simulation and analysis results show that the controlled retransmission scheme is more efficient than the previously suggested schemes regarding byte loss probability, successful retransmission rate, and network throughput.

• Transactions of the Korean Society of Automotive Engineers
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• v.5 no.2
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• pp.136-148
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• 1997

The present study has been carried out to develop a computational procedure for the analysis of the off-design performance in centrifugal compressors with vaneless diffusers by integrating empirical loss models and analytical equations. Losses in centrifugal compressors stem from a number of sources and their exact calculation is not yet possible. This study investigates several modeling schemes and shows that a fairly good prediction can be achieved by a proper selection of the most important flow parameters resulting form a meanline one-dimensional analysis. The performance maps for compressors are calculated and compared with measured performance maps. The off-design performance characteristics in terms of the pressure ratio vs. mass flow produced have generally correct forms. However, no universal means have been found to predict accurately the onset of surge. The prediction method developed through this study can serve as a tool to ensure good matching between parts and it can assist the understanding of the operational characteristics of general purpose centrifugal compressors.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.33A no.12
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• pp.33-38
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• 1996

In this paper, we modeled the complex dielectric constant and analyzed the projpagation characteristics of a FR-4 composite substrate with different compositions. From the wideband dielectric modeling and the propagation loss analysis of FR-4 composites that consists of FR-4 resin and E-glass reinforcement,we have found that the propagation loss and velocity increase with the volume fraction of FR-4 resin above 1 GHz. These results are helpful in determining to deisgn optimum substrate composition ratio and cross-sectional geometry of high-speed and high-density transmission line.