• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.23 no.3
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• pp.99-106
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• 2023

In this paper, we propose subregion-based area of interest management techniques for MMORPG(massively multiplayer online role playing games) integrating P2P(peer-to-peer) networking and cloud computing. For the crowded region, the proposed techniques partition it into several subregions and assign a player to manage each subregion as a coordinator. These techniques include a load balancing mechanism which regulates communication and computation overhead of such player below the specified threshold. We also provide a mechanism for satisfying the criterion, where subregions overlapped with each player's view must be switched quickly and seamlessly as the view moves around in the game world. In the proposed techniques where an efficient provisioning of resources is realized, they relieve a lot of computational power and network traffic, the load on the servers in the cloud by exploiting the capacity of the players effectively. Simulation results show that the MMORPG based on cloud and P2P architecture can reduce the considerable bandwidth at the server compared to the client server architecture as the available resources grow with the number of players in crowding or hotspots.

• Journal of Internet Computing and Services
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• v.15 no.2
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• pp.9-18
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• 2014

The sensors attached on/in a person are moved since human body frequency changes their activity, therefore in wireless body area networks, nodal mobility and non-line-of-sight condition will impact on performance of networks such as energy efficiency and reliable communication. We then proposed schemes which study on forwarding decisions against frequent change of topology and channel conditions to increase reliable connections and improve energy efficiency. In this work, we control the size of packets, forwarding rate based on ratio of input links and output links at each node. We also robust the network topology by extending the peer to peer IEEE 802.15.4-based. The adaptive topology from chain-based to grid-based can optimal our schemes. The simulation shows that these approaches are not only extending network lifetime to 48.2 percent but also increase around 6.08 percent the packet delivery ratio. The "hot spots" problem is also resolved with this approach.

• Journal of Electrical Engineering and Technology
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• v.13 no.6
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• pp.2479-2484
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• 2018

The filter bank multicarrier modulation (FBMC) technique is one of multicarrier modulation technique (MCM), which is mainly used to improve channel capacity of cognitive radio (CR) network and frequency spectrum access technique. The existing FBMC System contains serial to parallel converter, normal QAM modulation, Radix2 inverse FFT, parallel to serial converter and poly phase filter. It needs high area, delay and power consumption. To further reduce the area, delay and power of FBMC structure, a new clock gating technique is applied in the QAM modulation, radix2 multipath delay commutator (R2MDC) based inverse FFT and unified addition and subtraction (UAS) based FIR filter with parallel asynchronous self time adder (PASTA). The clock gating technique is mainly used to reduce the unwanted clock switching activity. The clock gating is nothing but clock signal of flip-flops is controlled by gate (i.e.) AND gate. Hence speed is high and power consumption is low. The comparison between existing QAM and proposed QAM with clock gating technique is carried out to analyze the results. Conversely, the proposed inverse R2MDC FFT with clock gating technique is compared with the existing radix2 inverse FFT. Also the comparison between existing poly phase filter and proposed UAS based FIR filter with PASTA adder is carried out to analyze the performance, area and power consumption individually. The proposed FBMC with clock gating technique offers low power and high speed than the existing FBMC structures.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39C no.12
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• pp.1289-1297
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• 2014

In this paper, we use the ECMA-392 standard, the first cognitive radio networks to meet the demand for IT services in the ship. We propose a ECMA-392 cooperative MAC protocol to ensure QoS to support multimedia services in the ship area in a multi-hop wireless bridge using ECMA-392 networks. Because the proposed protocol transmits directly or relay transmission by selecting efficient routes based on the information of the ECMA-392 devices, it provides communication to ensure QoS of the device. The simulation results show that the proposed cooperative MAC protocol improves a throughput of devices compared to the existing method.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.8 no.1
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• pp.39-45
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• 2008

High-Rate Wireless Personal Area Networks (HR-WPANs) in IEEE 802.15.3 standard use a TIme Devision Multiple Access (TDMA) protocol to support isochronous traffic. Isochronous traffic requires a delay-bounded service. However, the HR-WPAN standard suffers from long access delay and association delay. In this paper, we propose an enhanced MAC protocol for the delay-bounded traffic. This proposed protocol provides a way that a central node is able to collect traffic status on all member nodes. Furthermore, by utilizing the information, a scheduling algorithm is also proposed in order to synchronize the instant of a packet transmission with that of the packet arrival. With the proposed protocol and algorithm, the delay of access and association can be reduced. Performance analysis is carried out and the significant performance enhancement is observed.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.1
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• pp.221-237
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• 2016

The wireless body area networks (WBANs) consist of wearable computing devices and can support various healthcare-related applications. There exist two crucial issues when WBANs are utilized for healthcare applications. One is the protection of the sensitive biometric data transmitted over the insecure wireless channels. The other is the design of effective medical management mechanisms. In this paper, a secure medical information management system is proposed and implemented on a TinyOS-based WBAN test bed to simultaneously address these two issues. In this system, the electronic medical record (EMR) is bound to the biometric data with a novel fragile zero-watermarking scheme based on the modified visual secret sharing (MVSS). In this manner, the EMR can be utilized not only for medical management but also for data integrity checking. Additionally, both the biometric data and the EMR are encrypted, and the EMR is further protected by the MVSS. Our analysis and experimental results demonstrate that the proposed system not only protects the confidentialities of both the biometric data and the EMR but also offers reliable patient information authentication, explicit healthcare operation verification and undeniable doctor liability identification for WBANs.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.1
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• pp.43-49
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• 2011

A distance relay scheme is commonly used for backup protection. This scheme, called a step distance protection, is comprised of 3 steps for graded zones having different operating time. As for the conventional step distance protection scheme, Zone 2 can exceed the ordinary coverage excessively in case of a transformer protection relay especially. In this case, there can be overlapped protection area from a backup protection relay and, therefore, malfunctions can occur when any fault occurs in the overlapped protection area. Distance relays and overcurrent relays are used for backup protection generally, and both relays have normally this problem, the maloperation, caused by a fault in the overlapped protection area. Corresponding to an IEEE standard, this problem can be solved with the modification of the operating time. On the other hand, in Korea, zones are modified to cope with this problem in some specific conditions. These two methods may not be obvious to handle this problem correctly because these methods, modifying the common rules, can cause another coordination problem. To overcome this problem clearly, this paper describes an improved backup protection coordination scheme using an IEC 61850-based distance relay for transformer backup protection. IEC 61850-based IED(Intelligent Electronic Device) and the network system based on the kernel 2.6 LINUX are realized to verify the proposed method. And laboratory tests to estimate the communication time show that the proposed coordination method is reliable enough for the improved backup protection scheme.

• Journal of the Semiconductor & Display Technology
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• v.20 no.3
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• pp.71-76
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• 2021

Digital decimation filters are used in various digital signal processing systems using ADCs, including digital communication systems and sensor network systems. When the sampling rate of digital data is reduced, aliasing occurs. So, an anti-aliasing filter is necessary to suppress aliasing before down-sampling the data. Since the anti-aliasing filter has to have a sharp transition band between the passband and the stopband, the order of the filter is very high. However, as the order of the filter increases, the complexity and area of the filter increase, and more power is consumed. Therefore, in this paper, we propose two types of decimation filters, focusing on reducing the area of the hardware. In both cases, the complexity of the circuit is reduced by applying the required down-sampling rate in two times instead of at once. In addition, CIC decimation filters without a multiplier are used as the decimation filter of the first stage. The second stage is implemented using a CIC filter and a down sampler with an anti-aliasing filter, respectively. It is designed with Verilog-HDL and its function and implementation are validated using ModelSim and Quartus, respectively.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.18 no.6
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• pp.43-59
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• 2019

The Traffic controller currently used in Korea is a switch control system that directly transfers 220V of high voltage to traffic lights one to one. This method requires a lot of cables, and there are concerns about electric shock. Accordingly, Korea Road Traffic Authority added the digital communication signal controller standard using digital communication method to the standard specification of the communication signal controller of the National Police Agency. Based on these specifications, this paper intended to develop digital communication call controllers. In addition, it was verified that even if the digital communication signal controller and analogue communication call controller were mixed, they could operate in the signal control system currently in operation.

• Journal of Korea Society of Digital Industry and Information Management
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• v.13 no.4
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• pp.231-245
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• 2017

The purpose of this study is to analyze the trend line through scatter diagram analysis on correlation between SNS addiction tendencies and learning attitudes, figure out the knee point influencing learning attitudes negatively in detail, and examine influence among subareas. To address the goal, study questions are formulated as follows. First, this author did screening on the data of variables measured and analyzed descriptive statistics. Second, this researcher produced the trend line by drawing a scatter diagram in order to analyze correlation between SNS addiction tendencies, withdrawal symptoms, excessive communication, and excessive time wasting, and learning attitudes exploratorily. Third, to explore correlation between self-evaluation, learning participation, and developmental attitudes, the subfactors of learning attitudes related to SNS addiction tendencies, this author drew a scatter diagram and analyzed the threshold of positive and negative correlation. To verify the study questions, the SNS addiction tendency scale and learning attitude scale were applied to 301 university students in Chungcheong area. According to the study results, first, their learning attitudes are influenced by SNS addiction tendencies, excessive communication and excessive time wasting, and they are not influenced by withdrawal symptoms that much. Second, excessive communication, a factor of SNS addiction tendencies, and self-evaluation and developmental attitudes, factors of learning attitudes, show positive correlation to some extent and indicate negative correlation after the threshold. However, excessive communication and learning participation are found to show no correlation. Third, according to the results of examining correlation with learning attitudes by dividing them into excessive communication and excessive time wasting groups with the knee point of 1.40, as the symptom of excessive communication is found more, it influences self-evaluation, learning participation, developmental attitudes, and learning attitudes more negatively in general. The result of this study is expected to provide foundational material necessary to develop educational programs to prevent undergraduates' excessive SNS use and SNS addiction which can be used in the scenes of counseling or education.