• Journal of the Korea Institute of Information and Communication Engineering
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• v.22 no.3
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• pp.391-398
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• 2018

There are many problems caused by data sharing between general heterogeneous digital devices due to various interfaces. To solve this problem, this paper proposes heterogeneous data sharing with cloud service and mobile through D2D communication that supports communication between different devices. The proposed technique is used to reduce the load on the server to perform data synchronization. Also, in order to minimize data latency caused by data replication between different devices, a technique to enhance the speed of data writing with copying only the modified parts in the chunk list is adopted and cloud service model integrated with mobile environment is realized in order to minimize the network bandwidth consumed for synchronization for data sharing. Therefore, it is possible to share data in different spaces efficiently with maintaining data integrity and minimizing latency in data.

• Journal of KIISE:Computer Systems and Theory
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• v.31 no.11
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• pp.635-642
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• 2004

The traditional communication protocols such as TCP/IP are not suitable for PC cluster systems because of their high software processing overhead. To eliminate this overhead, industry leaders have defined the Virtual Interface Architecture (VIA). VIA provides two different data transfer mechanisms, a traditional Send/Receive model and the Remote Direct Memory Access (RDMA) model. RDMA is extremely efficient way to reduce software overhead because it can bypass the OS and use the network interface controller (NIC) directly for communication, also bypass the CPU on the remote host. In this paper, we have implemented VIA-based RDMA mechanism in hardware. Compared to the traditional Send/Receive model, the RDMA mechanism improves latency and bandwidth. Our RDMA mechanism can also communicate without using remote CPU cycles. Our experimental results show a minimum latency of 12.5${\mu}\textrm{s}$ and a maximum bandwidth of 95.5MB/s. As a result, our RDMA mechanism allows PC cluster systems to have a high performance communication method.

• The KIPS Transactions:PartA
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• v.8A no.4
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• pp.419-428
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• 2001

Advances in circuit and integration technology are continuously boosting the speed of processors. One of the main challenges presented by such developments is the effective use of powerful processors in shared memory multiprocessor system. We believe that the interconnection problem is not solved even for small scale shared memory multiprocessor, since the speed of shared buses is unlikely to keep up with the bandwidth requirements of new powerful processors. In the past few years, point-to-point unidirectional connection have emerged as a very promising interconnection technology. The single slotted ring is the simplest form point-to-point interconnection. The main limitation of the single slotted ring architecture is that latency of access increase linearly with the number of the processors in the ring. Because of this, we proposed the dual slotted ring as an alternative to single slotted ring for cache-based multiprocessor system. In this paper, we analyze the proposed dual slotted ring architecture using new snooping protocol and enforce simulation to compare it with single slotted ring.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.384-389
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• 2005

The objective on this project is to develop a cooperative Field Robot (FR), by using a customize Open Control Platform (OCP) as design and development process. An OCP is a CORBA-based solution for networked control system, which facilitates the transitioning of control designs to embedded targets. In order to achieve the cooperation surveillance system, two FRs are distributed by navigation messages (GPS and sensor data) using CORBA event-channel communication, while graphical information from IR night vision camera is distributed using CORBA Asynchronous Method Invocation (AMI). The QoS features of AMI in the network are to provide the additional delivery method for distributing an IR camera Images will be evaluate in this experiment. In this paper also presents an empirical performance evaluation from the variable chunk sizes were compared with the number of clients and message latency, some of the measurement data's are summarized in the following paragraph. In the AMI buffers size measurement, when the chuck sizes were change, the message latency is significantly change according to it frame size. The smaller frame size between 256 bytes to 512 bytes is more efficient fur the message size below 2Mbytes, but it average performance in the large of message size a bigger frame size is more efficient. For the several destination, the same experiment using 512 bytes to 2 Mbytes frame with 2 to 5 destinations are presented. For the message size bigger than 2Mbytes, the AMI are still able to meet requirement far more than 5 clients simultaneously.

• Journal of KIISE:Information Networking
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• v.29 no.2
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• pp.197-203
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• 2002

This paper proposes a new agent based mechanism called a Multicast Handoff Agent (MHA) to reduce handoff latency for IP multicast. The MHA acts as a proxy for an Internet Group Management Protocol (IGMP) of Mobile Nodes (MNs) at each Base Station (BS) and keeps information for members of multicast groups in a cell. When an MN moves to a next cell, the MHA immediately sends unsolicited reports without waiting for the IGMP query. The mechanism was evaluated through simulation and analysis and compared with the IGMPv2 for micro-mobility and the IGMP traffic. Simulation results show that handoff latency for micro-mobility can be largely reduced and the IGMP control traffic on the wireless links during the duration of membership can be eliminated. Thus, this mechanism is superior to the existing mechanism in both micro-mobility and battery duration, as the need not to reply to a query conserves battery power.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.18 no.5
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• pp.103-113
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• 2008

Reducing handoff latency is essential in providing seamless multimedia service in Wireless LAN based on the IEEE 802.11 standard. Reducing authentication delay is critical in reducing handoff latency. To this end, several authentication protocols for fBst handoff have been proposed. Mishra et al. used proactive key distribution to improve the authentication delay incurred in the current standard and Park et al. proposed a new authentication protocol based on Blom's key pre-distribution scheme. In this paper, we propose an enhanced authentication protocol based on Bresson et al.'s group key protocol. If a mobile node has previously access the network, our proposed protocol only requires simple hash operations in providing mutual authentication between a mobile node and access points. Our protocol is more efficient than Park et al.'s and Mishra et al.'s technique can be used in our protocol to further enhance our protocol.

• Journal of Korea Society of Digital Industry and Information Management
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• v.19 no.3
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• pp.61-75
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• 2023

In this paper, we design and experiment a 5G-based metaverse motion synchronization system with configuration of a mobile motion capture studio that has not been commercialized at home and abroad. As a result of the experiment, the average value of the latency test measurement using Wi-Fi is 0.134 seconds faster than the average latency test measurement value using the 5G network. Existing motion capture studios have spatial limitations as the motion capture range is limited to the Wi-Fi communication range. However, the 5G-based metaverse motion synchronization system configures a mobile motion capture studio so that motion performers can solve the spatial limitations by expanding the motion capture communication range indefinitely regardless of time and place. Therefore, it is possible to implement realistic metaverse contents by displaying a realistic and natural digital human because it is free from spatial constraints. The system which was tested in this paper can create a new business model by converging next-generation technologies that are receiving attention related to the digital virtual world, such as motion capture + 5G + digital human twin + metaverse. And it allows for research and develop a next-generation metaverse-based broadcasting solution at a recent time when the business value of digital human and metaverse technologies and functions has been proven and related sales are growing in earnest.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2022.05a
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• pp.115-117
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• 2022

Whitebox encryption technique is a method of preventing exposure of encryption keys by mixing encryption key information with a software-based encryption algorithm. Whitebox encryption technique is attracting attention as a technology that replaces conventional hardware-based security encryption techniques by making it difficult to infer confidential data and keys by accessing memory with unauthorized reverse engineering analysis. However, in the encryption and decryption process, a large lookup table is used to hide computational results and encryption keys, resulting in a problem of slow encryption and increased memory size. In particular, it is difficult to apply whitebox cryptography to low-cost, low-power, and light-weight Internet of Things products due to limited memory space and battery capacity. In addition, in a network environment that requires real-time service support, the response delay time increases due to the encryption/decryption speed of the whitebox encryption, resulting in deterioration of communication efficiency. Therefore, in this paper, we analyze whether the AES-based whitebox(WBC-AES) proposed by S.Chow can satisfy the speed and memory requirements based on the experimental results.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.3
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• pp.997-1005
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• 2010

Recently, there has been a growing interest in the use of WLAN technology due to its easy deployment, flexibility and so on. Examples of WLAN applications range from standard internet services such as Web access to real-time services with strict latency/throughput requirements such as multimedia video and voice over IP on wireless network environments. Fair and efficient distribution of the traffic loads among APs(Access Points) has become an important issue for improved utilization of WLAN. This paper focuses on an AP selection scheme for achieving better load balance, and hence increasing network resource utilization for each user on wireless network environments. This scheme makes use of active scan patterns and the network delay as main parameters of load measurement and AP selection. This scheme attempts to estimate the AP traffic loads by observing the up/down delay and utilize the results to maximize the link resource efficiency through load balancing. We compared the proposed scheme with the original SNR(Signal to Noise Ratio)-based scheme using the NS-2(Network Simulation.2). We found that the proposed scheme improves the throughput by 12.5% and lower the network up/down link delay by 36.84% and 60.42%, respectively. All in all, the new scheme can significantly increase overall network throughput and reduce up/down delay while providing excellent quality for voice and video services.

• IEMEK Journal of Embedded Systems and Applications
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• v.11 no.1
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• pp.39-46
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• 2016

According to general architecture of flight simulator made up of several independent rendering display systems, display synchronization problem between them naturally happens. In addition, since the flight simulator is usually implemented in the same networks where network delay is not big concern, it is necessary to consider different factors of existing synchronization technique. Among them, in this paper, we propose a new display synchronization scheme for flight simulator where each system has different rendering capacity. In the proposed scheme, each system is synchronized by considering maximum and minimum frames per second (FPS) while considering level of detail and latency. Also, experimental results are given to demonstrate the suitability of the proposed scheme for display synchronization scheme.