• Journal of the Korean Society of Industry Convergence
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• v.19 no.3
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• pp.109-124
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• 2016

The objective of this paper is to find the density, stiffness, and strength of truss-wall diamond corrugation model combined with pinwheel truss inside space. The truss-wall diamond corrugation (TDC) model is defined as a unit cell coming from solid-wall diamond corrugation (SDC) model. Pinwheel truss-wall diamond corrugation (P-TDC) model is made by TDC connected with pinwheel structure inside of the space. Derived ideal solutions of P-TDC is based on truss-wall and pinwheel truss model at first. And then it is compared with Gibson-Ashby's ideal solution. To validate the ideal solutions of the P-TDC, ABAQUS software is used to predict the density, strength, and stiffness, and then each of them are compared to the ideal solution of Gibson-Ashby with a log-log scale. Applied material property is stainless steel 304 because of having cost effectiveness. Applied parameters for P-TDC are 1 thru 5 mm diameter within fixed opening width as 4mm. In conclusion, the relative Young's modulus and relative yield strength of the P-TDC unit model is reasonable matched to the ideal expectations of the Gibson-Ashby's theory. In nearby future, P-TDC model is hoped to be applied to make sandwich core structure by advanced technologies such as 3D printing skills.

• Spatial Information Research
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• v.18 no.5
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• pp.133-142
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• 2010

Many pedestrian or fire evacuation models have been studied last decades for modeling evacuation behaviors or analysing building structures under emergency situations. However, currently developed models do not consider the differences of visibility of pedestrians by obstacles such as furniture, wall, etc. The visibility of pedestrians is considered one of the important factors that affect the evacuation behavior, leading to making simulation results more realistic. In order to incorporate pedestrian's visibility into evacuation simulation, we should be able to give different walking speeds according to differences of visibility. We improved the existing floor field model based on cellular automata in order to implement the visibility. Using the space syntax theory, we showed how we split the indoor spaces depending on the different visibilities created by different levels of structural depths. Then, we improved the algorithm such that pedestrians have different speeds instead of simultaneous movement to other cells. Also, in order for developing a real time simulation system integrated w ith indoor sensors later, we present a process to build a 3D simulator using a spatial DBMS. The proposed algorithm is tested using a campus building.

• The Journal of Korea Robotics Society
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• v.18 no.1
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• pp.1-9
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• 2023

This paper presents an optimal path planning strategy for aerial searching and surveying of a user-designated area using multiple Unmanned Aerial Vehicles (UAVs). The method is designed to deal with a single unseparated polygonal area, regardless of polygonal convexity. By defining the search area into a set of grids, the algorithm enables UAVs to completely search without leaving unsearched space. The presented strategy consists of two main algorithmic steps: cellular decomposition and path planning stages. The cellular decomposition method divides the area to designate a conflict-free subsearch-space to an individual UAV, while accounting the assigned flight velocity, take-off and landing positions. Then, the path planning strategy forms paths based on every point located in end of each grid row. The first waypoint is chosen as the closest point from the vehicle-starting position, and it recursively updates the nearest endpoint set to generate the shortest path. The path planning policy produces four path candidates by alternating the starting point (left or right edge), and the travel direction (vertical or horizontal). The optimal-selection policy is enforced to maximize the search efficiency, which is time dependent; the policy imposes the total path-length and turning number criteria per candidate. The results demonstrate that the proposed cellular decomposition method improves the search-time efficiency. In addition, the candidate selection enhances the algorithmic efficacy toward further mission time-duration reduction. The method shows robustness against both convex and non-convex shaped search area.

• Korean Journal of Food Science and Technology
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• v.45 no.2
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• pp.137-141
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• 2013

Flavonoids have various biological activities; however, their cellular uptake mechanism is beginning to be understood only recently. This review focuses on cellular flavonoids transport mechanisms in both plants and animals. In plants, flavonoids exist in various cellular compartments, providing a specialized transport system. Newly synthesized flavonoids can be transported from the endoplasmic reticulum to the vacuoles or extracellular space via cellular trafficking pathway. Among membrane transporters, ATP binding cassette, multidrug and toxic extrusion, bilitranslocase homologue transporters play roles in both the influx and efflux of cellular flavonoids across the cell membrane. In recent years, extensive researches have provided a better understanding on the cellular flavonoid transport in mammalian cells. Bilitranslocase transports flavonoids in various tissues, including the liver, intestine and kidneys. However, other transport mechanisms are largely unknown and thus, further investigation should provide detailed mechanisms, which can potentially lead to an improved bioavailability and cellular function of flavonoids in humans.

• Nuclear Engineering and Technology
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• v.43 no.3
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• pp.243-256
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• 2011

This paper considers the concept of analog computing based on a cellular neural network (CNN) paradigm to simulate nuclear reactor dynamics using a time-dependent second order form of the neutron transport equation. Instead of solving nuclear reactor dynamic equations numerically, which is time-consuming and suffers from such weaknesses as vulnerability to transient phenomena, accumulation of round-off errors and floating-point overflows, use is made of a new method based on a cellular neural network. The state-of-the-art shows the CNN as being an alternative solution to the conventional numerical computation method. Indeed CNN is an analog computing paradigm that performs ultra-fast calculations and provides accurate results. In this study use is made of the CNN model to simulate the space-time response of scalar flux distribution in steady state and transient conditions. The CNN model also is used to simulate step perturbation in the core. The accuracy and capability of the CNN model are examined in 2D Cartesian geometry for two fixed source problems, a mini-BWR assembly, and a TWIGL Seed/Blanket problem. We also use the CNN model concurrently for a typical small PWR assembly to simulate the effect of temperature feedback, poisons, and control rods on the scalar flux distribution.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.25 no.2
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• pp.343-362
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• 1995

The purpose of this study was to investigate chronic radiation effects on the basal cell of the rat tongue epithelium according to different irradiation timing. Forty-two female rats were devided into 5 experimental groups according to different irradiation timing and were irradiated single dose of 396cGy by MK cell irradiator using Cs-137. Experimental rats were sacrificed at the 2nd week, 4th week and 6th week after birth. The specimens were examined with light microscope and transmission electron microscope. The following results were obtained. 1. The first changes after irraditation were vacuoles. The vacuoles were chiefly observed in the cytoplasm, perinuclei area, and nuclei. 2. The most severe degenerative changes in the basal cell layer were observed in all experimental groups. ; cellular disarrangement, vacuole formation, widening of intercellular space, enlarged mitochondria & rER, and chromatin clumping were seen. 3. The cellular degenerative changes were most severe at the 4th week after birth in all experimental group, and the basal cell hyperplasia was seen at the 6th week in the most of experimental groups 4. The experimental groups 3 and 4 show more severe and more prolonged cellular degeneration than experimental groups 1 and 2, which were irradiated in pregnancy, and experimental group 5, which was irradiated after tongue maturation.

• IE interfaces
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• v.16 no.spc
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• pp.21-27
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• 2003

Objective of this paper is to develop the user mobility model(UMM) which is used for the performance analysis of location update and paging algorithm and at the same time, consider the user mobility pattern(UMP) in zone-based cellular networks. User mobility pattern shows correlation in space and time. UMM should consider these correlations of UMP. K-dimensional Markov chain is presented as a UMM considering them where the states of Markov chain are defined as the current location area(LA) and the consecutive LAs visited in the path. Also, a new two dimensional Markov chain composed of current LA and time interval is presented. Simulation results show that the appropriate size of K in the former UMM is two and the latter UMM reflects the characteristic of UMP well and so is a good model for the analytic method to solve the performance of location update and paging algorithm.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.2
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• pp.283-290
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• 2006

The cellular neural networks have the structure that consists of an array of the same cell which is a simple processing element, and each of the cells has local connectivity and space invariant template properties. So, it has a very suitable structure for the hardware implementation. But, it is impossible to have a one-to-one mapping between the CNN hardware processors and the pixels of the practical large image. In this paper, a $5{\times}5$ CNN hardware processor with pipeline input and output that can be applied to the time-multiplexing processing scheme, which processes the large image with a small CNN cell block, is designed. the operation of the implemented $5{\times}5$ CNN hardware processor is verified from the edge detection and the shadow detection experimentations.

• Journal of Advanced Navigation Technology
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• v.17 no.6
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• pp.700-704
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• 2013

Quantum-dot cellular automata(QCA) is a new technology and it is an one of the alternative high performance over existing complementary metal-oxide semi-conductor(CMOS). QCA is nanoscale device and ultra-low power consumption compared with transistor-based technologies, and various circuits using QCA technology have been proposed. Binary-coded decimal(BCD), which represents decimal digits in binary, is mainly used in electronic circuits and Microprocessor, and it is comfortable in conversion operation but many data loss. In this paper, we present an BCD-EXCESS 3 Code converter which can be efficiently used for subtraction and half adjust. The proposed scheme has efficiently designed considering space and time complexities and minimization of noise, and it has been simulated and confirmed.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.10 no.5
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• pp.87-92
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• 2011

In this paper, we got the 800 ~ 900 MHz path loss model for Russia PNG area using the free space model and the Okumura-Hata Model. In order to add new regional properties to the existing path loss model, the mean square error technique is used to obtain the correction factor. The correction factors for the free space and the Hata model are 28, 13 dB respectively. By applying this correction factors, the new Russain PNG path loss model is proposed.