• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.45 no.12
• /
• pp.58-65
• /
• 2008

This paper presents a new geographic distributed hash table (GDHT) for MANETs or Mesh networks, where virtual geographic protocol is used. In previous wort GDHT is applied to a network scenario based on two dimensional Cartesian coordinate system. Further, logical data space is supposed to be uniformly distributed. However, mobile node distribution in a network using virtual geographic routing is not matched to data distribution in GDHT. Therefore, if we apply previous GDHT to a virtual geographic routing network, lots of DHT data are probably located at boundary nodes of the network or specific nodes, resulting in long average-delay to discover resource (or service). Additionally, in BVR(Beacon Vector Routing) or LCR(Logical Coordinate Routing), because there is correlation between coordinate elements, we cannot use normal hash function. For this reason, we propose to use "geographic hash function" for GDHT that matches data distribution to node distribution and considers correlation between coordinate elements. We also show that the proposed scheme improves resource discovery efficiently.

• Journal of the Korean Association of Geographic Information Studies
• /
• v.14 no.2
• /
• pp.138-146
• /
• 2011

With the increased use of GPS in the field of various applications including surveying, the request for fast and precise positional information has increased. Several countries such as USA, Canada, and Australia have already been operating Internet-based automatic GPS data analysis system using e-mail and FTP. Expanding GPS market, it is necessary to establish automatic GPS baseline processing system that is accessible via Internet. The system developed in this study is operating on the web, and it allows the users to access easily regardless of time and place. The main processing engines are Bernese V5.0 and PAGES. They process user data with three GPS CORS(Continuously Operating Reference Station), and then send the report to the users through e-mail. This system allows users to process high accurate GPS data easily. It is expected that this system will be used for various GPS applications such as monitoring large-scale structures and providing spatial information services in private sector.

• KIPS Transactions on Software and Data Engineering
• /
• v.6 no.1
• /
• pp.1-8
• /
• 2017

Given a multi-dimensional dataset of tuples, a skyline query returns a subset of tuples which are not 'dominated' by any other tuples. Skyline query is very useful in Big data analysis since it filters out uninteresting items. Much interest was devoted to the MapReduce-based parallel processing of skyline queries in large-scale distributed environment. There are three requirements to improve parallelism in MapReduced-based algorithms: (1) workload should be well balanced (2) avoid redundant computations (3) Optimize network communication cost. In this paper, we introduce MR-SEAP (MapReduce sample Skyline object Equality Angular Partitioning), an efficient angular space partitioning based skyline query processing using sampling-based pruning, which satisfies requirements above. We conduct an extensive experiment to evaluate MR-SEAP.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2017.10a
• /
• pp.346-348
• /
• 2017

The speed of technology development is increasing, and high-performance digital devices are spreading. Smart walks that can work effectively anytime and anywhere by being restricted from space and time in wired digital devices such as PC, System security design is needed to secure integrity and availability against various security threats such as physical threats such as lost, stolen and damaged terminals, technical threats such as theft, denial of service, and unauthorized access, compared with the wired environment. In this paper, we analyze smart work network system, wired / wireless link system, and digital smart device. We study security design method for smart work wired system and future wireless system which are used in present work. This study will be used as basic data for building a secure smart work.

• Journal of Advanced Navigation Technology
• /
• v.25 no.5
• /
• pp.384-389
• /
• 2021

An optimal ground station (GS) antenna pattern design method for network-based UAV command and control communication systems considering complexity and performance is presented. The GS antenna consists of multiple side sectors and one upward sector. The antenna gain for each vertical/horizontal angle of the GS antenna according to the change of antenna design parameters such as the number of sectors, horizontal and vertical beam-width, and tilt-angle is modeled, and the effect of the parameter changes on the signal-to-noise ratio (SNR) distribution in the virtual three-dimensional space is analyzed. It is observed that the tilt-angle of the side sectors has the greatest effect on the performance, and the longer the distance between GSs, the higher the maximum altitude and the smaller the number of side sectors, the tilt-angle should be lower. In addition, it is observed that the wider vertical beam-width of the side sector is advantageous in maximizing the lowest SNR, but narrow vertical beam-width is advantageous in maximizing the average SNR.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.23 no.2
• /
• pp.207-214
• /
• 2019

The speed of technological development is increasing, and high-performance digital devices are spreading. Wired digital devices such as PCs have been optimized for existing wired environments, but needs are shifting away from the constraints of space and space to smart work that enables efficient work anywhere and anytime. The Smart Work System security design is needed to secure integrity and availability in the face of various security threats including physical threats (lost, stolen, and damaged terminals), technical threats (data theft, DoS: denial of service), and unauthorized access outside the wired environment. In this study, we analyzed smart work network systems, wired / wireless link systems, and digital smart devices. We also studied cyber-attack analysis and cybersecurity design methods for a Smart Work wired system and a future wireless system. This study will be used as basic data for building a secure Smart Work system.

• Journal of the Korea Institute of Information Security & Cryptology
• /
• v.21 no.1
• /
• pp.177-186
• /
• 2011

Mobile services which are applied PC performance and mobile characteristics are increased with spread of the smartphone. Recently, mobile cloud service is getting the spotlight as a solution of mobile service problems that mobile device is lack of memory, computing power and storage and mobile services are subordinate to a particular mobile device platform. However, mobile cloud service has more potential security threats by the threat inheritance of mobile service, wireless network and cloud computing service. Therefore, security threats of mobile cloud service has to be removed in order to deploy secure mobile cloud services and user and manager should be able to respond appropriately in the event of threat. In this paper, We define mobile cloud service threats by threat analysis of mobile device, wireless network and cloud computing and we propose mobile cloud service countermeasures in order to respond mobile cloud service threats and threat scenarios in order to respond and predict to potential mobile cloud service threats.

• Journal of Broadcast Engineering
• /
• v.26 no.1
• /
• pp.61-69
• /
• 2021

Image outpainting is a very interesting problem in that it can continuously fill the outside of a given image by considering the context of the image. There are two main challenges in this work. The first is to maintain the spatial consistency of the content of the generated area and the original input. The second is to generate high quality large image with a small amount of adjacent information. Existing image outpainting methods have difficulties such as generating inconsistent, blurry, and repetitive pixels. However, thanks to the recent development of deep learning technology, deep learning-based algorithms that show high performance compared to existing traditional techniques have been introduced. Deep learning-based image outpainting has been actively researched with various networks proposed until now. In this paper, we would like to introduce the latest technology and trends in the field of outpainting. This study compared recent techniques by analyzing representative networks among deep learning-based outpainting algorithms and showed experimental results through various data sets and comparison methods.

• Journal of Digital Convergence
• /
• v.20 no.4
• /
• pp.791-797
• /
• 2022

Through recent metaverse marketing case studies, success factors and activation methods were analyzed from the perspective of content, platform, network, and device of the metaverse ecosystem in each industry. The importance of contents and platform of metaverse could be found in entertainment, fashion, office space and real estate, education, advertisement and commerce industries. In order to vitalize the metaverse, firstly, it is necessary to strengthen active participation and retention by providing a stable revenue model for market participants. Secondly, the importance of attractive content to expand subscribers is a key trigger for metaverse activation. Thirdly, it is necessary to increase the convenience of using metaverse service by using a light and simple device for the user. Fourthly, a win-win cooperation strategy should be supported in the value chain of the industry through ecosystem scalability. In addition, business opportunities for market participants and additional revenue models should be continuously provided.

• The KIPS Transactions:PartC
• /
• v.14C no.1 s.111
• /
• pp.27-38
• /
• 2007

IPv6 has appeared for solving the address exhaustion of IPv4 and for guaranteeing the problems of security and QoS. It occurs the unexpected new attacks of IPv6 as well as the existing attacks of IPv4 because of the increasing address space to 128bits and the address hierarchies for efficient network management and additions of the new messages between nodes and routers like neighbor discovery and auto address configuration for the various comfortable services. For the successful transition from IPv4 to IPv6, we should get the secure compatibility between IPv4 hosts or routers working based on secure and systematic policy and IPv6. Network manager should design security technologies for efficient management in IPv4/IPv6 co-existence network and IPv6 network and security management framework designation. In this paper, we inspected the characteristics of IPv4 and IPv6, study on security requirement for efficient security management of various attacks, protocol, service in IPv4/IPv6 co-existence and IPv6 network, and finally suggest integrated solution about security vulnerability of IPv6 network in considering of analysis of IPv6 system, host and application, IPv6 characteristics, modified CGA(MCGA).