• International Journal of Computer Science & Network Security
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• v.23 no.10
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• pp.147-156
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• 2023

Electronic voting machines (EVMs) are replacing research ballots due to the errors involved in the manual counting process and the lengthy time required to count the votes. Even though these digital recording electronic systems are advancements, they are vulnerable to tampering and electoral fraud. The suspected vulnerabilities in EVMs are the possibility of tampering with the EVM's memory chip or replacing it with a fake one, their simplicity, which allows them to be tampered with without requiring much skill, and the possibility of double voting. The vote data is shared among all network devices, and peer-to-peer verification is performed to ensure the vote data's authenticity. To successfully tamper with the system, all of the data stored in the nodes must be changed. This improves the proposed system's efficiency and dependability. Elections and voting are fundamental components of a democratic system. Various attempts have been made to make modern elections more flexible by utilizing digital technologies. The fundamental characteristics of free and fair elections are intractability, immutability, transparency, and the privacy of the actors involved. This corresponds to a few of the many characteristics of blockchain-like decentralized ownership, such as chain immutability, anonymity, and distributed ledger. This working research attempts to conduct a comparative analysis of various blockchain technologies in development and propose a 'Blockchain-based Electronic Voting System' solution by weighing these technologies based on the need for the proposed solution. The primary goal of this research is to present a robust blockchain-based election mechanism that is not only reliable but also adaptable to current needs.

• The Journal of the Korea institute of electronic communication sciences
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• v.19 no.1
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• pp.19-24
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• 2024

In this paper, in order to realize lower cut-off frequency of the waveguide, the folded Ridge waveguide (FRWG) is suggested by alternating T-shape structure in the conventional folded waveguide with Y-shape structure. Suggested FRWG can be equivalent by the reverse Ridge waveguide. As the height of side of the FRWG is lower, the width of side is increased. Therefore, the cut-off frequency of the FRWG can be decreased more than half compared with conventional waveguide. The FRWG is designed with the length, height, and width of Y-shape structure of 40mm, 20mm, and 2mm, respectively. Designed FRWG has the cut-off frequency of the 1.996GHz. Also, the transition between the FRWG and SMA connector is designed. The transition is optimized by the capacitance of the signal line of the connector. Its result shows the VSWR under 2:1 in the band of 2.064 ~ 3.050 GHz. Suggested FRWG can be applied with miniaturization of various waveguide devices.

• Journal of IKEEE
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• v.28 no.1
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• pp.104-109
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• 2024

In this research, we explored the influence of post-annealing atmospheres on the electrical properties of Ga₂O₃/SiC heterojunction diodes. We fabricated Ga₂O₃/SiC heterojunction diodes by RF sputtering and after the fabrication the post-annealing in various gas atmospheres was performed. We measured the changes in deep-level defects using Deep Level Transient Spectroscopy (DLTS) and we conducted an electrical characteristic of J-V measurement and Hall measurement to analyzed the effects of annealing atmosphere on Ga₂O₃/SiC heterojunction diode. In the N₂ annealed devices, the highest on-state current was measured as 3.06 × 10^-2 A/cm^2, and an increase in carrier concentration of 3.8 × 10¹⁴ cm^-3 was observed. This confirms that the variations in deep level defects due to the post-annealing atmosphere can influence the electrical properties.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.18 no.7
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• pp.1986-2009
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• 2024

The integration of blockchain technology with the rapid growth of Internet of Things (IoT) devices has enabled secure and decentralised data exchange. However, security vulnerabilities and performance limitations remain significant challenges in IoT blockchain networks. This work proposes a novel approach that combines transaction representation and machine learning techniques to address these challenges. Various clustering techniques, including k-means, DBSCAN, Gaussian Mixture Models (GMM), and Hierarchical clustering, were employed to effectively group unlabelled transaction data based on their intrinsic characteristics. Anomaly transaction prediction models based on classifiers were then developed using the labelled data. Performance metrics such as accuracy, precision, recall, and F1-measure were used to identify the minority class representing specious transactions or security threats. The classifiers were also evaluated on their performance using balanced and unbalanced data. Compared to unbalanced data, balanced data resulted in an overall average improvement of approximately 15.85% in accuracy, 88.76% in precision, 60% in recall, and 74.36% in F1-score. This demonstrates the effectiveness of each classifier as a robust classifier with consistently better predictive performance across various evaluation metrics. Moreover, the k-means and GMM clustering techniques outperformed other techniques in identifying security threats, underscoring the importance of appropriate feature selection and clustering methods. The findings have practical implications for reinforcing security and efficiency in real-world IoT blockchain networks, paving the way for future investigations and advancements.

• Science of Emotion and Sensibility
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• v.11 no.3
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• pp.301-312
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• 2008

Satisfaction of consumer preferences is a key factor for the success of the products. Therefore, design mangers try to develop the profitable products through the intensive survey on the consumer preferences. Although the studies on the preferable product design and the design factors have long been carried out, most of these studies dealt only with the design factors preferable for individual product category ignoring the relationship of the product categories which are related to each other. For designers and design managers, in this study, we propose the guidelines of successful product development by finding preferred common and distinct design factors through analysis of the relations between the consumer preferences and design factors in various portable electric devices. To this end, we analyzed the preferred common and distinct design factors from portable electric devices including the electronic dictionaries, notebook computers, cellular phones, and MP3 players. We used hierarchical regression analysis for the effects of the design factors on the preferences among the product categories and regression analysis for the effects among each product category. The analysis on the preferred common design factors among the four product categories revealed that consumers did not care about the whole body type but preferred white color, metallic and glassy texture in the body. Also, the preferred design factors in the each product category are as follows; oval body shape and black color in electronic dictionaries, white color, metallic and glassy texture in notebook computers, plastic texture in cellular phones, rectangular body shape and plastic texture in MP3 players. In the case of notebook computers, the preferred common and distinct design factors were the same. We expect these results will be helpful for designers and design managers to identify the preferred design factors to consider when developing the various portable electric devices.

• Journal of dental hygiene science
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• v.9 no.3
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• pp.339-344
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• 2009

The purpose of this study was to examine the knowledge of some adults about oral hygiene devices and their use of the oral hygiene devices. After a survey was conducted from December 3 to 17,2007, the answer sheets from 352 respondents were gathered. and the collected data were analyzed with a SPSS Ver. 17.0 program. The findings of the study were as follows. 1. Concerning the level of knowledge, the adults investigated knew the best that a toothbrush should be kept by making the head upward (76.77). On the other hand, they had little knowledge on water pick, tongue cleaner and interdental brush. 2. As for the level of use, they scored highest on keeping their toothbrushes by making the head upward(76.77), In contrast, they scarcely put water pick, electronic toothbrushes, tongue cleaner to use. 3. Knowledge impact of general characteristics involving mate(62.54). 50s over(66.28) and up, four family members(61.54), graduate school graduate(66.78), self-employed and, professionals(63.63), income of 1 to 1.5 million won(66.66), fathers were smokers(51.89) got the highest marks with a mean. 4. Use impact of the general characteristics female(47.70), 40s over 49s under(47.78), four family members(48.18), graduate school graduate(50.17), professionals(49.79), income of 1 to 1.5 million won(51.89), fathers were smokers(48.10) got the highest marks with a mean.

• Journal of the Microelectronics and Packaging Society
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• v.10 no.1
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• pp.31-38
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• 2003

In the current electronic technology atmosphere, MEMS (Microelectromechanical System) technology is regarded as one of promising device manufacturing technologies to realize market-demanding device properties. In the packaging of MEMS devices, the packaged structure must maintain hermeticity to protect the devices from a hostile atmosphere during their operations. For such MEMS device vacuum packaging, we introduce the LTCC (Low temperature Cofired Ceramic) packaging technology, in which embedded passive components such as resistors, capacitors and inductors can be realized inside the package. The technology has also the advantages of the shortened length of inner and surface traces, reduced signal delay time due to the multilayer structure and cost reduction by more simplified packaging processes owing to the realization of embedded passives which in turn enhances the electrical performance and increases the reliability of the packages. In this paper, the leakage rate of the LTCC package having several interfaces was measured and the possibility of LTCC technology application to MEMS devices vacuum packaging was investigated and it was verified that improved hermetic sealing can be achieved for various model structures having different types of interfaces (leak rate: stacked via; $4.1{\pm}1.11{\times}10^{-12}$/ Torrl/sec, LTCC/AgPd/solder/Cu-tube; $3.4{\pm}0.33{\times}10^{-12}$/ Torrl/sec). In real application of the LTCC technology, the technology can be successfully applied to the vacuum packaging of the Infrared Sensor Array and the images of light-up lamp through the sensor way in LTCC package structure was presented.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.08a
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• pp.176-176
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• 2010

One of the critical issues for applications of flexible organic thin film transistors (OTFTs) for flexible electronic systems is the electrical stabilities of the OTFT devices, including variation of the current on/off ratio (Ion/Ioff), leakage current, threshold voltage, and hysteresis under repetitive mechanical deformation. In particular, repetitive mechanical deformation accelerates the degradation of device performance at the ambient environment. In this work, electrical stability of the pentacene organic thin film transistors (OTFTs) employing multi-stack hybrid encapsulation layers was investigated under mechanical cyclic bending. Flexible bottom-gated pentacene-based OTFTs fabricated on flexible polyimide substrate with poly-4-vinyl phenol (PVP) dielectric as a gate dielectric were encapsulated by the plasma-deposited organic layer and atomic-layer-deposited inorganic layer. For cyclic bending experiment of flexible OTFTs, the devices were cyclically bent up to 105 times with 5mm bending radius. In the most of the devices after 105 times of bending cycles, the off-current of the OTFT with no encapsulation layers was quickly increased due to increases in the conductivity of the pentacene caused by doping effects from $O_2$ and $H_2O$ in the atmosphere, which leads to decrease in the Ion/Ioff and increase in the hysteresis. With encapsulation layers, however, the electrical stabilities of the OTFTs were improved significantly. In particular, the OTFTs with multi-stack hybrid encapsulation layer showed the best electrical stabilities up to the bending cycles of $10^5$ times compared to the devices with single organic encapsulation layer. Changes in electrical properties of cyclically bent OTFTs with encapsulation layers will be discussed in detail.

• Proceedings of the Materials Research Society of Korea Conference
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• 2012.05a
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• pp.68.1-68.1
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• 2012

The best part of graphene is - charge-carriers in it are mass less particles which move in near relativistic speeds. Comparing to other materials, electrons in graphene travel much faster - at speeds of $10^8cm/s$. A graphene sheet is pure enough to ensure that electrons can travel a fair distance before colliding. Electronic devices few nanometers long that would be able to transmit charge at breath taking speeds for a fraction of power compared to present day CMOS transistors. Many researches try to check a possibility to make it a perfect replacement for silicon based devices. Graphene has shown high potential to be used as interconnects in the field of high frequency electrical devices. With all those advantages of graphene, we demonstrate characteristics of electrical and optical properties of graphene such as the effect of graphene geometry on the microwave properties using the measurements of S-parameter in range of 500 MHz - 40 GHz at room temperature condition. We confirm that impedance and resistance decrease with increasing the number of graphene layer and w/L ratio. This result shows proper geometry of graphene to be used as high frequency interconnects. This study also presents the optical properties of graphene oxide (GO), which were deposited in different substrate, or influenced by oxygen plasma, were confirmed using different characterization techniques. 4-6 layers of the polycrystalline GO layers, which were confirmed by High resolution transmission electron microscopy (HRTEM) and electron diffraction analysis, were shown short range order of crystallization by the substrate as well as interlayer effect with an increase in interplanar spacing, which can be attributed to the presence of oxygen functional groups on its layers. X-ray photoelectron Spectroscopy (XPS) and Raman spectroscopy confirms the presence of the $sp^2$ and $sp^3$ hybridization due to the disordered crystal structures of the carbon atoms results from oxidation, and Fourier Transform Infrared spectroscopy (FTIR) and XPS analysis shows the changes in oxygen functional groups with nature of substrate. Moreover, the photoluminescent (PL) peak emission wavelength varies with substrate and the broad energy level distribution produces excitation dependent PL emission in a broad wavelength ranging from 400 to 650 nm. The structural and optical properties of oxygen plasma treated GO films for possible optoelectronic applications were also investigated using various characterization techniques. HRTEM and electron diffraction analysis confirmed that the oxygen plasma treatment results short range order crystallization in GO films with an increase in interplanar spacing, which can be attributed to the presence of oxygen functional groups. In addition, Electron energy loss spectroscopy (EELS) and Raman spectroscopy confirms the presence of the $sp^2$ and $sp^3$ hybridization due to the disordered crystal structures of the carbon atoms results from oxidation and XPS analysis shows that epoxy pairs convert to more stable C=O and O-C=O groups with oxygen plasma treatment. The broad energy level distribution resulting from the broad size distribution of the $sp^2$ clusters produces excitation dependent PL emission in a broad wavelength range from 400 to 650 nm. Our results suggest that substrate influenced, or oxygen treatment GO has higher potential for future optoelectronic devices by its various optical properties and visible PL emission.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.10a
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• pp.205-208
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• 2015

Large vessels are currently operating by using an ECDIS, a system enabling automatic navigation and checking marine conditions. In the past, the ECDIS was used for vessels but in these days, it has been used as a method for collecting and verifying marine information, etc. from land by using a computer, instead of taking a boat out. The ECDIS on sale is generally used by companies which operate marine workers. However, this system has caused inconvenience to marine workers, in terms of tasks, services, or operations. Marine workers move out to the sea after checking the status of the system at the office. Due to the weather such as waves and winds, marine devices are not often found on the relevant coordinates. In such a case, the workers onerously need to come back to the land and track the marine devices again. In order to solve such a problem, this thesis purposes to develop a system which can check the locations of marine devices and verify a marine chart even on the sea by using a mobile. The proposed system can integrate and support a variety of protocols of relevant devices in the system itself and check data via mobile through the data transmission and streaming functions.