• Journal of Convergence for Information Technology
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• v.8 no.5
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• pp.69-75
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• 2018

The purpose of access control is to prevent computing resources from illegal behavior such as leakage, modification, and destruction by unauthorized users. As the cloud computing environment is expanded to resource sharing services using virtualization technology, a new security model and access control technique are required to provide dynamic and secure cloud-based computing services. The virtualization management convergence access control model provides a flexible user authorization function by applying the dynamic privilege assignment function to the role based access control mechanism. In addition, by applying access control mechanism based on security level and rules, we solve the conflict problem in virtual machine system and guarantee the safeness of physical resources. This model will help to build a secure and efficient cloud-based virtualization management system and will be expanded to a mechanism that reflects the multi-level characteristics.

• Journal of the Korean Institute of Telematics and Electronics C
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• v.36C no.6
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• pp.52-62
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• 1999

This paper presents a system which recognizes dynamic hand gestures on-line for controlling motion of numan avatar in virtual environment(VF). A dynamic hand gesture is a method of communication between a computer and a human being who uses gestures, especially both hands and fingers. A human avatar consists of 32 degree of freedom(DOF) for natural motion in VE and navigates by 8 pre-defined dynamic hand gestures. Inverse kinematics and dynamic kinematics are applied for real-time motion control of human avatar. In this paper, we apply a fuzzy min-max neural network and feature analysis method using fuzzy logic for on-line dynamic hand gesture recognition.

• Korean Journal of Construction Engineering and Management
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• v.7 no.1 s.29
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• pp.148-158
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• 2006

Public construction companies have strictly followed a rule that they should not do the works using water such as concrete pouring for the structural frame for a certain period during the winter season. It is usually known that the designated non-working period during the winter causes increase of the project duration and the project cost escalation. The halted work also makes negative effects on national economy because it reduces worker's income. However, the situation would be a lot better if the work for the structural frame is allowed under some conditions. The structural framework done alone without being followed by finish works gives a lot of stresses on the finish works. In this sense, this study examines how the structural framework performed during the winter season affect on the critical path of the finish works. To accomplish the objective of this research, the subnet for the finish works as well as a master network are prepared along with critical paths for a virtual construction site. Using the prepared networks, simulations are carried out to see the effects described above. This study is expected to be used in estimating the construction duration of high-rise apartment housing when the site work for the structural frame should be performed during this period.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.3B
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• pp.339-348
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• 2004

Packet classification is an important factor to support various services such as QoS guarantee and VPN for users in Internet. Packet classification is a searching process for best matching rule on rule tables by employing multi-field such as source address, protocol, and port number as well as destination address in If header. In this paper, we propose hardware based packet classification algorithm by employing tree bitmap of multi-bit trio. We divided prefixes of searching fields and rule into multi-bit stride, and perform a rule searching with multi-bit of fixed size. The proposed scheme can reduce the access times taking for rule search by employing indexing key in a fixed size of upper bits of rule prefixes. We also employ a marker prefixes in order to remove backtracking during searching a rule. In this paper, we generate two dimensional random rule set of source address and destination address using routing tables provided by IPMA Project, and compare its memory usages and performance.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.12 no.3
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• pp.99-114
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• 2012

Proxy Mobile IPv6 (PMIPv6) has received considerable attention between telecommunications and the Internet communities and does not require active participation of the Mobile Node (MN) by way of network-based mobility management. The PMIPv6 domain is studying establishment in progress to support extensively a number of MN by using a low handover latency. In this research, we are propose a novel 3S scheme for building Scalable and Secure and Seamless PMIPv6 domains. In the proposed scheme, all of Mobility Access Gateway (MAG) are acting as the Local Mobility Anchor (LMA) and composing a virtual ring with another MAG. General hashing is used in the efficient distribution-mapping between each MN and the MN's LMA of all MAGs. And, MAG and MN are authenticated using the symmetric key. Through mathematical analysis, we verifies the safety, scalability, and seamless service for 3S. Also, we're propose a handover procedure of 3S and show better than the existing schemes in terms of handover latency.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.05a
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• pp.270-273
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• 2015

In shipbuilding and marine industry, engineering and design software solutions have upgraded from the original 2D schematic data based CAD system to a modern 3D drawing-based system. Due to the fact that the massive amount of data usage in real time and data volumes of various engineering models including graphic data have increased, several problems such as lack of server resources and improper handling of 3D drawings have been raised. Besides, increasing the number of session connections per server can cause deterioration of server performance. Recently, increasing the yard's sophisticated design capabilities highlighted the need to develop engineering and design system which would not only overcome the network performance issues, but would provide efficient collaborative design environment. This paper presents an overview of the framework for collaborative engineering design system based on the virtual application (Citrix XenApp 6.5)and acceleration hardware technology of 3D graphics (NVIDIA GRID K2 solution).

• The KIPS Transactions:PartC
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• v.11C no.6 s.95
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• pp.747-754
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• 2004

Today, wireless LANs are widely deployed in various places such as corporate office conference rooms, industrial warehouses, Internet-ready classrooms, etc. However, new concerns have been raised regarding suity. Currently, both virtual private network(VPN) and WEP are used together as a strong authentication mechanism. While security is increased by using VPN and WEP together, unnecessary redundancy occurs causing power consumption increase and authentication speed decrease in the authentication process. In this paper a new synchronization protocol for authentication is proposed which allows simple authentication, minimal power consumption at the mobile station, and high utilization of authentication stream. This is achieved by using one bit per a frame authentication, while main authentication process including synchronization is handled by access points. Computer simulation reveals that the proposed scheme significantly improves the authentication efficiency in terms of the number of authenticated frames and authentication speed compared with an earlier protocol employing a similar authentication approach.

• The Bulletin of The Korean Astronomical Society
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• v.42 no.2
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• pp.61.1-61.1
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• 2017

As the application of deep-learning methods has been succeeded in various fields, they have a high potential to be applied to space weather forecasting. Convolutional neural network, one of deep learning methods, is specialized in image recognition. In this study, we apply the AlexNet architecture, which is a winner of Imagenet Large Scale Virtual Recognition Challenge (ILSVRC) 2012, to the forecast of daily solar flare occurrence using the MatConvNet software of MATLAB. Our input images are SOHO/MDI, EIT $195{\AA}$, and $304{\AA}$ from January 1996 to December 2010, and output ones are yes or no of flare occurrence. We consider other input images which consist of last two images and their difference image. We select training dataset from Jan 1996 to Dec 2000 and from Jan 2003 to Dec 2008. Testing dataset is chosen from Jan 2001 to Dec 2002 and from Jan 2009 to Dec 2010 in order to consider the solar cycle effect. In training dataset, we randomly select one fifth of training data for validation dataset to avoid the over-fitting problem. Our model successfully forecasts the flare occurrence with about 0.90 probability of detection (POD) for common flares (C-, M-, and X-class). While POD of major flares (M- and X-class) forecasting is 0.96, false alarm rate (FAR) also scores relatively high(0.60). We also present several statistical parameters such as critical success index (CSI) and true skill statistics (TSS). All statistical parameters do not strongly depend on the number of input data sets. Our model can immediately be applied to automatic forecasting service when image data are available.

• Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
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• 1999.12a
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• pp.66-71
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• 1999

For given 3D geographic data which is usually of DEM(Data Elevation Model) format, we have to represent and manipulate the data in various ways. For example, we have to draw a part of them in drawing canvas. To do this we give users a way of selecting area they want to visualize. And we have to give a base tool for users to select the local area which can be chosen for some geographic operation. In this paper, we propose a 3D data processing method for representation and manipulation. The method utilizes the major properties of DEM and TIN(Triangular Irregular Network), respectively. Furthermore, by approximating DEM with a TIN of an appropriate resolution, we can support a fast and realistic surface modeling. We implement the structure with the following 4 level stages. The first is an optimal resolution of DEM which represent all of wide range of geographic data. The second is the full resolution DEM which is a subarea of original data generated by user's selection in our implemeatation. The third is the TIN approximation of this data with a proper resolution determined by the relative position with the camera. And the last step is multi-resolution TIN data whose resolution is dynamically decided by considering which direction user take notice currently. Specialty, the TIN of the last step is designed for realtime camera navigation. By using the structure we implemented realtime surface clipping, efficient approximation of height field and the locally detailed surface LOD(Level of Detail). We used the initial 10-meter sampling DEM data of Seoul, KOREA and implement the structure to the 3D Virtual GIS based on the Internet.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.63 no.1
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• pp.40-45
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• 2014

This study examines the system and process of battery stored energy in vehicles and suggest the effective area for the use of V2G(vehicle-to-grid) from Jeju Smart Grid Demonstration Project. V2G means technology of electric power transmission from the battery of electric-drive vehicles to state grid. As for the increasing of effectiveness for demand-side control, V2G is a very good alternative. In the U.S., the utilization of electric vehicles is under 40% on average. In this case, we can use he battery of electric vehicle as role of frequency regulation or generator of demand-side resource. V2G, which is the element of Smart Transportation, consists of electric vehicle battery, BMS(battery management system), OBC(on-board charger), charging infrastructure, NOC(network operating center) and TOC(total operation center). V2G application has been tested for frequency regulation to secure the economical efficiency in the United States. In this case, the battery cycle life is not verified its disadvantage. On the other hand, Demand Response is required by low c-rate of battery in electric vehicle and It can be small impact on the battery cycle life. This paper concludes business area of demand response is more useful than frequency regulation in V2G application of electric vehicles in Korea. This provides the opportunity to create a new business for power grid administrator with VPP(virtual power plant).