• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.16 no.1
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• pp.24-32
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• 2023

The current Private 5G use procedure goes through the step of application examination, use and usage inspection, and can be divided in to application, examination step as a procedure before frequency allocation, and use, usage inspection step as a procedure after frequency allocation. Various types of documents are required to apply for a Private 5G, and due to the document screening process and radio station inspection for using Private 5G frequencies, the procedure for Private 5G applicants to use Private 5G is complicated and takes a considerable amount of time. In this paper, we proposed Frequency Allocation Process for Private 5G using a blockchain platform, which is fast and simplified than the current procedure. Through the use of a blockchain platform and NFT (Non-Fungible Token), reliability and integrity of the data required in the frequency allocation process were secured, and security of frequency usage information was maintained and a reliable Private 5G frequency allocation process was established. Also by applying the RPA system that minimizes human intervention, fairness was secured in the process of allocating Private 5G. Finally, the frequency allocation process of Private 5G based on the Ethereum blockchain was performed though a simulation.

• Fire Science and Engineering
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• v.29 no.4
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• pp.15-20
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• 2015

This study compared, through a fire simulation, temperature changes of the smoke layer and the air layer, and height fluctuations of the smoke layer, according to the sprinkler head installation and non-installation, and the sprinkler head types in elderly-care facilities. When a standard response sprinkler worked, the radiant heat exceeded the conditions for the occurrence of flashover. However the ESFR sprinkler prevented flashover. When the early response head worked, inhabitants were not damaged by radiant heat because the maximum value of the heat flux remained $2,293W/m^2$, which is less then the burn hazard criterion of $4,000W/m^2$. The highest temperature of the room when fire occurred exceeded the safety standard in all of the smoke layer and the air layer, but the highest temperature was kept below the safety standard after it fell down rapidly. Because the height of the smoke layer was maintained above 1.1 m when the early response sprinkler worked, the falling of the smoking layer was much more delayed than in the case where the standard response sprinkler was used.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.4B
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• pp.347-356
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• 2009

This study simulates the dam break situation by a probable maximum precipitation of Soyang-River Dam using HEC-HMS model and HEC-RAS model and compares the simulated results. The probable maximum precipitation was calculated using the flood event of the typhoon Rusa occurred in 2002 and using the mean areal precipitation of the Gangreung region and the moisture maximization method. The estimated probable maximum precipitations were compared for the duration of 6, 12, 18, and 24 hrs and were used as input data for the HEC-HMS model. Moreover, the inflow data calculated by HEC-HMS were utilized as ones for HEC-RAS, and then unsteady flow analysis was conducted. The two models were used for the dam break analysis with the same conditions and the peak flow estimated by HEC-HMS was larger than that of the HEC-RAS model. The applicability of two models was performed from the dam break analysis then we found that we could simulate more realistic peak flow by HEC-RAS than HEC-HMS. However, when we need more fast simulation results we could use HEC-HMS. Therefore, we may need the guidelines for the different utilizations with different purposes of two models. Furthermore, since the two models still include uncertainties, it is important to establish more detailed topographical factors and data reflecting actual rivers.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.2C
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• pp.133-142
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• 2006

Many methods have been tried to more correctly measure rock joint roughness. However, true roughness may be distorted and underestimated due to the sampling interval and measurement method. Thus, currently used measurement methods produce a dead zone and distort roughness profiles. The purpose of this study is to suggest new roughness measurement method by a camera-type 3D scanner as an alternative of currently used methods. First, the underestimation of artificial roughness is analyzed by using the current measurement method such as laser profilometry. Second, we replicate eight specimens from two rock joint surfaces, and digitize by a 3D scanner. Then, the roughness coefficient values obtained from eight numbers of 3D surface data and from three hundred twenty numbers of 2D profiles data are analyzed by using current and new measurement methods. The artificial simulation confirms that the sampling interval is one of main factors for the distortion of roughness and shows that inclination of waviness may not be considered any current methods. The experimental results show that the camera-type 3D scanner produces 10% larger roughness values than current methods. As the proposed new method is a fast, high precision and more accurate method for the roughness measurement, it should be a promising technique in this area.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.3D
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• pp.423-429
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• 2008

The object of the present study is to estimate the potential effects of climate change and land use on soil erosion in the mid-east Korea. Simulated precipitation by CCCma climate model during 2030-2050 is used to model predicted soil erosion, and results are compared to observation. Simulation results allow relative comparison of the impact of climate change on soil erosion between current and predicted future condition. Expected land use changes driven by socio-economic change and plant growth driven by the increase of temperature and are taken into accounts in a comprehensive way. Mean precipitation increases by 17.7% (24.5%) for A2 (B2) during 2030-2050 compared to the observation period (1966-1998). In general predicted soil erosion for the B2 scenario is larger than that for the A2 scenario. Predicted soil erosion increases by 48%~90% under climate change except the scenario 1 and 2. Predicted soil erosion under the influence of temperature-induced fast plant growth, higher evapotranspiration rate, and fertilization effect (scenario 5 and 6) is approximately 25% less than that in the scenario 3 and 4. On the basis of the results it is said that precipitation and the corresponding soil erosion is likely to increase in the future and care needs to be taken in the study area.

• Applied Chemistry for Engineering
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• v.35 no.1
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• pp.16-22
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• 2024

Polymer electrolyte membrane fuel cells have the advantage of low operating temperatures and fast startup and response characteristics compared to others. Simulation studies are actively researched because their cost and time benefits. In this study, the resistance of water residual in the gas diffusion layer (GDL) of the unit cell was added to the existing equation to compare the actual data with the model data. The experiments were conducted with a 25 cm² unit cell, and the samples were separated into stopping times of 0, 10, and 60 minutes following primary impedance measurement, activation, and polarization curve data acquisition. This gives 0, 10, and 60 minutes for the residual water in the GDL to evaporate. Without the rest period, the magnitude of the performance improvement was not significantly different at the same potential and flow rate, but the rest period did improve the performance of the membrane electrode assembly when measuring impedance. By changing the magnitude of the resistance reduction to an overvoltage, the voltage difference between the fuel cell model with and without residual water was compared, and the error rate in the high current density region, which is dominated by concentration losses, was reduced.

• Journal of Internet of Things and Convergence
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• v.10 no.3
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• pp.19-24
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• 2024

Recent advances in large-scale data processing technologies such as big data, cloud computing, and artificial intelligence have increased the demand for high-performance storage devices in data centers and enterprise environments. In particular, the fast data response speed of storage devices is a key factor that determines the overall system performance. Solid state drives (SSDs) based on the Non-Volatile Memory Express (NVMe) interface are gaining traction, but new bottlenecks are emerging in the process of handling large data input and output requests from multiple hosts simultaneously. SSDs typically process host requests by sequentially stacking them in an internal queue. When long transfer length requests are processed first, shorter requests wait longer, increasing the average response time. To solve this problem, data transfer timeout and data partitioning methods have been proposed, but they do not provide a fundamental solution. In this paper, we propose a dual queue based scheduling scheme (DQBS), which manages the data transfer order based on the request order in one queue and the transfer length in the other queue. Then, the request time and transmission length are comprehensively considered to determine the efficient data transmission order. This enables the balanced processing of long and short requests, thus reducing the overall average response time. The simulation results show that the proposed method outperforms the existing sequential processing method. This study presents a scheduling technique that maximizes data transfer efficiency in a high-performance SSD environment, which is expected to contribute to the development of next-generation high-performance storage systems

• Cartoon and Animation Studies
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• s.20
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• pp.75-86
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• 2010

Recently, as the number of female players has increased rapidly, the electronic gaming industry has begun to look at ways to appeal to the largely untapped female market. According to the latest game market investigative report by China Internet Network Information Center (CNNIC), the total number of game players in China increased by 24.8% in 2009, reached 69,130,000 people, and 38.9% of them are female players. This growth in the number of female player is corroborated by a series of investigative reports from IResearch Company in Shanghai, China: from 2003 to 2009, the number of female players grew from 8% to more than 49%. Therefore, no matter how much attention the game production companies have given to male players or how they have ignored the female players before, the companies would be sensible to face up this reality and adjust their marketing policy a bit more. This article analyzes gender preferences in video games which shows that male players are more likely to be attracted to elements of aggression, violence, competition and fast action in electronic game-playing, while female players are drawn to emotional and social aspects of the games such as an understanding of character relationships. The literatures cited indicates that female players also show apparent preference for games with familiar environments, games that allow players to work together, games that have more than one way to win, and games in which characters do not die. It also discusses the characteristics of female-friendly games from the aspect of emotion, pointing out that the simulation games involving pet, dressing-up, and social simulation games are very popular with female players. Because these are the most suitable game types to fill with emotions of love, share, jealousy, superiority, mystery, these are absolutely attractive to female players. Finally, in accord with the above, I propose some principles of designing female-oriented games, including presenting a good-looking leading character, making the story interesting with "live" NPCs(Non-Playing Characters), and finding ways to satisfy female nature instincts such as taking care of others and the inborn interest of classifying and selecting.

• Korean Journal of Agricultural Science
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• v.12 no.1
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• pp.118-127
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• 1985

The grain temperature is a crucial factor determining the deterioration rate of stored grain. Therefore, it is used to be predicted in order to evaluate the various stored methods rapidly and inexpensively. In this study, a mathematical model was developed to simulate the temperatures of grain stored in a cylinderical bin. It was formulated for the two dimensional heat transfer by the finite difference method. Then, it was verified statistically using the actual test deta and the predicted. The changes of grain temperature were analyed using the simulated data of one year for a safe stoarge and the following results were obtained: 1. Simulation model developed by the finite difference method was validated with the actual and the predicted grain temperatures and it's result showed that it could predict the grain temperature of storage bin reasonably well. 2. Grain temperature near the wall of storage bin were changed with $6-7^{\circ}C$ higher then average atmospheric temperature from June to September. Therefore, the parts of stored grain near the wall is supposed to be deteriorated fast. 3. When the dimension of bin diameter is about the same as the bed height, the changes of grain temperature of radial direction was higher than the verticals. 4. The predicted temperature showed that the grain temperature of which were from the end of April to mid October were higher than the safe storage limit at Yusung, Korea.

• Journal of the Korea Society for Simulation
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• v.18 no.3
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• pp.73-82
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• 2009

Due to the many advantages including low price, low power consumption, and miniaturization, the CMOS camera has been utilized in many applications, including mobile phones, the automotive industry, medical sciences and sensoring, robotic controls, and research in the security field. In particular, the 360 degree omni-directional camera when utilized in multi-camera applications has displayed issues of software nature, interface communication management, delays, and a complicated image display control. Other issues include energy management problems, and miniaturization of a multi-camera in the hardware field. Traditional CMOS camera systems are comprised of an embedded system that consists of a high-performance MCU enabling a camera to send and receive images and a multi-layer system similar to an individual control system that consists of the camera's high performance Micro Controller Unit. We proposed the SL-AVS (Small Size/Low power Around-View System) to be able to control a camera while collecting image data using a high speed synchronization technique on the foundation of a single layer low performance MCU. It is an initial model of the omni-directional camera that takes images from a 360 view drawing from several CMOS camera utilizing a 110 degree view. We then connected a single MCU with four low-power CMOS cameras and implemented controls that include synchronization, controlling, and transmit/receive functions of individual camera compared with the traditional system. The synchronization of the respective cameras were controlled and then memorized by handling each interrupt through the MCU. We were able to improve the efficiency of data transmission that minimizes re-synchronization amongst a target, the CMOS camera, and the MCU. Further, depending on the choice of users, respective or groups of images divided into 4 domains were then provided with a target. We finally analyzed and compared the performance of the developed camera system including the synchronization and time of data transfer and image data loss, etc.