• Journal of the Korean Institute of Intelligent Systems
• /
• v.19 no.5
• /
• pp.609-614
• /
• 2009

The purpose of this paper is to design the metal object detection system for drive inside protection. To do this, we propose the algorithm for designing the color filter that can detect the metal object using fuzzy theory and the algorithm for detecting area of the driver's face using fuzzy skin color filter. Also, by using the proposed algorithm, we propose the algorithm for detecting the metallic object candidate regions. And, the metallic object color filter is then applied to find the candidate regions. Finally, we show the effectiveness and feasibility of the proposed method through some experiments.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2008.11a
• /
• pp.397-400
• /
• 2008

Traditional propellants which have a hypergolic characteristic have a high performance but also have disadvantages of toxicity and complex handling requirement. In order to replace these propellants, one of the alternatives is hydrogen peroxide which generates high temperature oxygen and water vapor after catalytic reaction. In this paper, autoignition characteristics of kerosene by decomposed hydrogen peroxide were investigated to perform fundamental research for designing a thruster using hydrogen peroxide and kerosene propellants. Contraction ratio, whether flame holder exists or not, and feeding pressure of propellants were selected as variables. From the experiments for different mixture ratio, we confirmed the ignition stability is strongly affected by a feeding pressure of propellants.

• Wind and Structures
• /
• v.28 no.2
• /
• pp.111-128
• /
• 2019

In this paper an octagon plan shaped building (study building) in presence of three square plan shaped building is subjected to boundary layer wind flow and the interference effects on the study building is investigated using Computational fluid dynamics. The variation of the pressure coefficients on different faces of the octagon building is studied both in isolated and interference conditions. Interference Factors (IF) are calculated for different faces of the study building which can be a powerful tool for designing similar plan shaped buildings in similar conditions. A metamodel of the IF, in terms of the distances among buildings is also established using Response Surface Method (RSM). This set of equations are optimized to get the optimum values of the distances where the IF is unity. An upstream Interference zone for this building setup and wind environment is established from these data. Uncertainty principle is also utilised to determine the optimum positions of the interfering buildings considering the uncertain nature of wind flow for minimum interference effect. The proposed procedure is observed to be computationally efficient in deciding optimum layout at buildings often required in city planning. The results show that the proposed RSM-based optimization approach captures the interference zone accurately with substantially less number of experiments.

• Journal of Positioning, Navigation, and Timing
• /
• v.7 no.4
• /
• pp.245-253
• /
• 2018

The current SBAS service does not provide a method to integrate multiple SBAS corrections. This paper proposes a positioning method to effectively integrate multiple SBAS and multiple GNSS. In the method, the final position is obtained by the weighted sum of the positions obtained from the combination of GNSS and SBAS. Since each position is independently computed and combined using flexible weights, it has a simple structure that can easily cope with various environments. In order to verify the operation and performance of the proposed method, raw measurements of GNSS and SBAS were collected using commercial receivers. The experiments using real signals show that the combined use of two SBAS corrections was more accurate by 0.05~0.4m(2dRMS) than using only one SBAS correction. To improve the position accuracy, this paper considered the integration of multi-GNSS and multi-SBAS, which was not found in other existing studies. The proposed method is expected to be a core technology for designing multi-GNSS navigation receivers considering multi-SBAS corrections. The importance of the method will be increased as KPS and KASS also available in near future.

• Advances in materials Research
• /
• v.8 no.1
• /
• pp.11-24
• /
• 2019

This paper presents a review study for energy-efficient gas turbines (GTs) with cycles which contributes significantly towards sustainable usage. Nonetheless, these progressive engines, operative at turbine inlet temperatures as high as $1600^{\circ}C$, require the employment of highly creep resistant materials for use in hotter section components of gas turbines like combustion chamber and blades. However, the gas turbine obtain its driving power by utilizing the energy of treated gases and air which is at piercing temperature and pushing by expanding through the several rings of steady and vibratory blades. Since the turbine blades works at very high temperature and pressure, high stress concentration are observed on the blades. With the increasing demand of service, to provide adequate efficiency and power within the optimized level, turbine blades are to be made of those materials which can withstand high thermal and working load condition for longer cycle time. This paper depicts the recent developments in the field of implementing the best suited materials for the GTs, selection of proper Thermal Barrier Coating (TBC), fracture analysis and experiments on failed or used turbine blades and several other designing and operating factors which are effecting the blade life and efficiency. It is revealed that Nickel based Superalloys were promising, Cast Iron with Zirconium and Pt-Al coatings are used as best TBC material, material defects are the foremost and prominent reason for blade failure.

• Smart Media Journal
• /
• v.8 no.3
• /
• pp.53-61
• /
• 2019

In this paper, designing and implementing multi-communication middleware in multi-thread environmet through event-based synchronization method are proposed for stable data transmission of electronic optical equipment, which requires combining camera and various sensors to process multiple high-speed data. To verify the performance of the implemented communication middleware, image data and sensor data were sent to compare differences in reception-based and transmission-based cycles, and the maximum number of communication possibilities to transmit and process multiple was measured and analyzed. In addition, the proposed communication middleware's performance was verified through experiments such as validating the integrity of the transmitted data and measuring the Round Trip Time.

• Nuclear Engineering and Technology
• /
• v.51 no.7
• /
• pp.1715-1720
• /
• 2019

Jozef Stefan Institute (JSI), TRIGA Mark II reactor employs the homogeneous mixture of uranium and zirconium hydride fuel type. Since its upgrade, a series of fresh fuel steady state experimental benchmarks have been conducted. The benchmark results have provided data for testing computational neutronics codes which are important for reactor design and safety analysis. In this work, we investigated the JSI TRIGA Mark II reactor neutronics characteristics: the effective multiplication factor and two safety parameters, namely the control rod worth and the fuel temperature reactivity coefficient using SuperMC. The modeling and real-time cross section generation methods of SuperMC were evaluated in the investigation. The calculation analysis indicated the following: the effective multiplication factor was influenced by the different cross section data libraries; the control rod worth evaluation was better with Monte Carlo codes; the experimental fuel temperature reactivity coefficient was smaller than calculated results due to change in water temperature. All the results were in good agreement with the experimental values. Hence, SuperMC could be used for the designing and benchmarking of other TRIGA Mark II reactors.

• Journal of Technologic Dentistry
• /
• v.42 no.4
• /
• pp.402-408
• /
• 2020

Purpose: To understand the students' level of recognition of online classes in the Department of Dental Technology and to provide the basic data for designing online classes based on the dental technology course. Methods: A survey was conducted among the students of the dental technology department. The collected data was analyzed with the SPSS ver. 25.0 program. To ensure a reliable verification, the α=0.05 significance level was used. The t-test and analysis of variance were also performed. Results: The students' level of recognition of online classes in the Department of Dental Technology is shown in the rate of recognition for video-based classes for both the theory and experiments. Students displayed high positivity with the video-based learning as it is repeated learning that is not affected by the limitations of time. In addition, video-based learning is highly beneficial in terms of convenience, satisfaction, and achievement for learning. Conclusion: Based on the results, video-based learning is a highly positive learning type for students. It was also recommended that the Department of Dental Technology should offer a post-COVID-19 online class to include the blended methods of a face-to-face class and video-based learning.

• Journal of Distribution Science
• /
• v.19 no.2
• /
• pp.53-64
• /
• 2021

Purpose: Even though arranging images of products is a common practice in the online retail context, relatively little attention has been paid to the distance effect among alternatives, that is, how distance among displayed products can impact consumers' responses. Drawing on contagion theory, the primary goal of the current study is to investigate how spatial distance between two products in a product display can influence consumers' perceived similarity. Research design, data and methodology: This study used a 2(spatial distance: close vs. far) experimental design and collected data from undergraduate students in Korea through an online survey using Qualtrics. ANOVA was conducted to test the proposed effect, in which the dependent variables are the perceived similarity of usage occasion/purpose (Study 1) and the indexed differences of perceived brand statuses between two products (Study 2). Results: The results of both experiments indicated that the displayed products were perceived to be more similar to one another when products were presented close together (vs. far). Conclusions: The results help to fill a research gap and provide a better understanding of the role of physical distance in diverse marketing communications. This is especially useful when designing online shopping websites to form perceptions of brand images.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.15 no.1
• /
• pp.114-130
• /
• 2021

With the drastic growth of Information and Communication Technology (ICT) industry, global energy consumption is exponentially increased by mobile communications. The huge energy consumption and increased environmental awareness have triggered great interests on the research of dynamic distribution of cell user and traffic, and then designing the energy efficient cellular network. In this paper, we explore the temporal and spatial characteristics of human mobility and traffic distribution using real data set. The analysis results of cell traffic illustrate the tidal effect in temporal and spatial dimensions and obvious periodic characteristics which can be used to design Base Station (BS) dynamic with sleeping or shut-down strategy. At the same time, we designed a new Cell Zooming and BS cooperation mode. Through simulation experiments, we found that running in this mode can save about 35% of energy consumption and guarantee the required quality of service.