• Journal of Advanced Navigation Technology
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• v.23 no.1
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• pp.36-43
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• 2019

In this paper, a novel channel access scheme for the next-generation vehicle to anything (V2X) system based on IEEE 802.11p standard which is applied to recent connected car technologies is suggested and analyzed. The proposed scheme proposes a channel access method utilizing OFDMA multi-user transmission for IEEE 802.11p based system. In this paper, the authors examine geographical distance and network area performance of IEEE 802.11p system and the proposed scheme. Results of this research show that the proposed scheme is quite suitable for improving conventional V2X standards and systems. This paper also provides mathematical analysis and simulation results of the conventional IEEE 802.11p system and the proposed scheme.

• Journal of Advanced Navigation Technology
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• v.27 no.6
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• pp.861-864
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• 2023

Recently, V2X (vehicle-to-everyting) communication has established itself as an essential technology for cooperative autonomous driving. V2X communication currently includes DSRC (dedicated short range communication) communication technology, which is a WLAN (wireless local area network) based communication technology, and C-V2X (cellular-V2X) communication technology, which is a Cellular-based communication technology. Since these two communication methods are not compatible with each other, various studies and experiments are being conducted to select one of the two communication methods. In the case of C-V2X communication, there are LTE-V2X (long term evolutionV2X) communication technology, which is an initial version, and 5G-V2X communication technology, which is a next-generation version. 5G-V2X communication technology has been completed only until standardization, so LTE-V2X communication technology is mainly used. In this paper, we introduce trends related to various issues in V2X communication, including communication method decisions.

• International Journal of Internet, Broadcasting and Communication
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• v.12 no.1
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• pp.7-13
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• 2020

We describes V2X technology, a connectivity-based recognition technology that is attracting attention as a key technology for implementing autonomous driving technology, and autonomous communication modules that implement ADAS technology, a sensor-based recognition technology. It also explains the trends in V2X technology standardization centered on IEEE 802.11p, which is a WAVE technology standard based on Wi-Fi/DSRC. Finally, we will discuss the market growth trend of V2X communication modules in the United States, the leading V2X technology module, and the development of technology development trends of major domestic and international companies that are leading the global technology market related to V2X communication modules. V2X and ADAS technologies will be the biggest influence on automotive purchasing decisions. In recent years, V2I mandates have been promoted beyond V2V, mainly in developed countries such as the United States. The related industry needs to focus on the development of information transmission network technology that can support high frequency high efficiency(transmission rate) and sophisticated positioning accuracy beyond conventional vehicle communication.

• Annual Conference of KIPS
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• 2024.05a
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• pp.891-894
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• 2024

The quest for reliability in Artificial Intelligence (AI) is progressively urgent, especially in the field of next generation wireless networks. Future Beyond 5G (B5G)/6G networks will connect a huge number of devices and will offer innovative services invested with AI and Machine Learning tools. Wireless communications, in general, and medium access control (MAC) techniques were among the fields that were heavily affected by this improvement. This study presents the applications and services of future communication networks. This study details the Medium Access Control (MAC) scheduler of Beyond-5G/6G from 3^rd Generation Partnership (3GPP) and highlights the current open research issues which are yet to be optimized. This study provides an overview of how AI plays an important role in improving next generation communication by solving MAC-layer issues such as resource scheduling and queueing. We will select C-V2X as our use case to implement our proposed MAC scheduling model.

• Proceedings of the Materials Research Society of Korea Conference
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• 2011.05a
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• pp.28.2-28.2
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• 2011

Resistance random access memory (ReRAM) is a promising candidate for next-generation nonvolatile memory because of its advantageous qualities such as simple structure, superior scalability, fast switching speed, low-power operation, and nondestructive readout. We investigated the resistive switching behavior of tantalum oxide that has been widely used in dynamic random access memories (DRAM) in the present semiconductor industry. As a result, it possesses full compatibility with the entrenched complementary metal-oxide-semiconductor processes. According to previous studies, TiN is a good oxygen reservoir. The TiN top electrode possesses the specific properties to control and modulate oxygen ion reproductively, which results in excellent resistive switching characteristics. This study presents fully room temperature fabricated the TiN/$TaO_x$/Pt devices and their electrical properties for nonvolatile memory application. In addition, we investigated the TiN electrode dependence of the electrical properties in $TaO_x$ memory devices. The devices exhibited a low operation voltage of 0.6 V as well as good endurance up to $10^5$ cycles. Moreover, the benefits of high devise yield multilevel storage possibility make them promising in the next generation nonvolatile memory applications.

• Microbiology and Biotechnology Letters
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• v.48 no.4
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• pp.574-581
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• 2020

Next generation sequencing is commonly used to characterize the microbiome structure. MiSeq is commonly used to analyze the microbiome due to its relatively long read length. However, recently, Illumina introduced the 250x2 chip for HiSeq 2500. The purpose of this study was to compare the performance of MiSeq and HiSeq in the context of oral microbiome samples. The MiSeq Reagent Kit V3 and the HiSeq Rapid SBS Kit V2 were used for MiSeq and HiSeq 2500 analyses, respectively. Total read count, read quality score, relative bacterial abundance, community diversity, and relative abundance correlation were analyzed. HiSeq produced significantly more read sequences and assigned taxa compared to MiSeq. Conversely, community diversity was similar in the context of MiSeq and HiSeq. However, depending on the relative abundance, the correlation between the two platforms differed. The correlation between HiSeq and MiSeq sequencing data for highly abundant taxa (> 2%), low abundant taxa (2-0.2%), and rare taxa (0.2% >) was 0.994, 0.860, and 0.416, respectively. Therefore, HiSeq 2500 may also be compatible for microbiome studies. Importantly, the HiSeq platform may allow a high-resolution massive parallel sequencing for the detection of rare taxa.

• Journal of IKEEE
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• v.28 no.3
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• pp.310-320
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• 2024

This article describes the 5G-NR-V2X system and its communication performance methodology. We present a system that can develop and verify the performance of self-driving services in a real road test environment using OBU and RSU for 5G-NR-V2X communication (level 4 or higher). This system ensures ultra-high speed (150Mbps or more), ultra-low latency (3ms or less), and high reliability (99.99 percent) in communication robustness, even under malicious conditions. The 5G-NR-V2X system and performance analysis method proposed in this paper are anticipated to aid in the development of V2X communication technologies that are ultrafast, ultralow-delay, and high-confidence. In addition, it is expected that the services validated by the suggested performance analysis technique will enhance technological competitiveness in the road, transportation, logistics, and commerce industries.

• Journal of Advanced Navigation Technology
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• v.23 no.6
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• pp.589-596
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• 2019

With the proliferation of intelligent transportation system (ITS) with dedicated short-range communication (DSRC) deployment, there are various applications requiring different throughput and reliability performance. To meet the enhanced throughput requirements in newly generated applications, IEEE 802.11bd is proposed to standardize for support of enhanced throughput and latency, preserving the fairness with previously deployed WLAN V2X devices. One of the main features of IEEE 802.11 bd is 20 MHz transmission to support the high data rate. In this paper, the primary channel selection method is proposed to guarantee the fairness with frame transmissions with 10 MHz bandwith including communications in WLAN V2X devices deployed with IEEE 802.11p. Simulation shows that the proposed channel access method for 20 MHz transmission with primary selection preserves the fairness without the change of channel access method in wide-band transmission.

• Journal of Intelligence and Information Systems
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• v.22 no.1
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• pp.107-118
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• 2016

The advent of 5G mobile communications, which is expected in 2020, will provide many services such as Internet of Things (IoT) and vehicle-to-infra/vehicle/nomadic (V2X) communication. There are many requirements to realizing these services: reduced latency, high data rate and reliability, and real-time service. In particular, a high level of reliability and delay sensitivity with an increased data rate are very important for M2M, IoT, and Factory 4.0. Around the world, 5G standardization organizations have considered these services and grouped them to finally derive the technical requirements and service scenarios. The first scenario is broadcast services that use a high data rate for multiple cases of sporting events or emergencies. The second scenario is as support for e-Health, car reliability, etc.; the third scenario is related to VR games with delay sensitivity and real-time techniques. Recently, these groups have been forming agreements on the requirements for such scenarios and the target level. Various techniques are being studied to satisfy such requirements and are being discussed in the context of software-defined networking (SDN) as the next-generation network architecture. SDN is being used to standardize ONF and basically refers to a structure that separates signals for the control plane from the packets for the data plane. One of the best examples for low latency and high reliability is an intelligent traffic system (ITS) using V2X. Because a car passes a small cell of the 5G network very rapidly, the messages to be delivered in the event of an emergency have to be transported in a very short time. This is a typical example requiring high delay sensitivity. 5G has to support a high reliability and delay sensitivity requirements for V2X in the field of traffic control. For these reasons, V2X is a major application of critical delay. V2X (vehicle-to-infra/vehicle/nomadic) represents all types of communication methods applicable to road and vehicles. It refers to a connected or networked vehicle. V2X can be divided into three kinds of communications. First is the communication between a vehicle and infrastructure (vehicle-to-infrastructure; V2I). Second is the communication between a vehicle and another vehicle (vehicle-to-vehicle; V2V). Third is the communication between a vehicle and mobile equipment (vehicle-to-nomadic devices; V2N). This will be added in the future in various fields. Because the SDN structure is under consideration as the next-generation network architecture, the SDN architecture is significant. However, the centralized architecture of SDN can be considered as an unfavorable structure for delay-sensitive services because a centralized architecture is needed to communicate with many nodes and provide processing power. Therefore, in the case of emergency V2X communications, delay-related control functions require a tree supporting structure. For such a scenario, the architecture of the network processing the vehicle information is a major variable affecting delay. Because it is difficult to meet the desired level of delay sensitivity with a typical fully centralized SDN structure, research on the optimal size of an SDN for processing information is needed. This study examined the SDN architecture considering the V2X emergency delay requirements of a 5G network in the worst-case scenario and performed a system-level simulation on the speed of the car, radius, and cell tier to derive a range of cells for information transfer in SDN network. In the simulation, because 5G provides a sufficiently high data rate, the information for neighboring vehicle support to the car was assumed to be without errors. Furthermore, the 5G small cell was assumed to have a cell radius of 50-100 m, and the maximum speed of the vehicle was considered to be 30-200 km/h in order to examine the network architecture to minimize the delay.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.37 no.6
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• pp.649-656
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• 2024

Memristors, as next-generation memory devices, have garnered significant academic interest. Among them, TiO₂/TiO_2-x based memristors have particularly attracted substantial scholarly attention. Research on the activation and stability of TiO₂ based memristor devices through process parameters is essential. Here, to determine the impact of process parameters on the activation of TiO₂/TiO_2-x based memristor devices, we fabricated the memristor devices using a sputtering system and conducted annealing at 400℃. Additionally, to analyze the electrical characteristics of the devices, we measured the I-V curves and C-V curves. Also, we examined TiO₂/TiO_2-x based memristor devices surface using SEM. Consequently, it was observed that the devices subjected to annealing exhibited improved hysteresis curves in the I-V characteristics, a reduced bandgap, and changes in resistance compared to the non-annealed devices. The retention test results further demonstrated that the set/reset characteristics of the devices were stable, confirming their potential applicability as memory devices.