• Journal of KIISE:Databases
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• v.27 no.2
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• pp.227-237
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• 2000

A Web database System is a large-scaled multimedia application system that has multimedia processing facilities and cooperates with relational/Object-Oriented DBMS. Conventional hypertext modeling methods and DB gateway have limitations for Web database because of their restricted versatile presentation abilities and inefficient concurrency control caused by bottleneck in cooperation processing. Thus, we suggest a Dynamic Navigation Model & Virtual Graph Structure. The Dynamic Navigation Model supports implicit query processing and dynamic creation of navigation spaces, and introduce node-link creation rule considering navigation styles. We propose a mapping methodology between the suggested hypertext model and the relational data model, and suggest a dynamic allocation scheduling technique for query processing server based on weighted value. We show that the proposed technique enhances the retrieval performance of Web database systems in processing complex queries concurrently.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.4 no.4
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• pp.767-773
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• 2000

As computer systems and communication technologies develop rapidly, CSCW(Computer Supported Collaborative Work) system appears nowadays, through which it is available to work on virtual space without any restriction of time and place. Most of CWCS systems depend on a special network and groupware. The systems of graphics and CAD are not so many because they are specified by hardware and application software. In this paper, we propose a web-based collaborative CAD system, which can be jointly worked on Internet WWW being independent from any platforms. It can create and modify 3D objects easily using VRML and Java 3D API, and it can send, print, and store them. The interactive work for designing objects can be also carried out through chatting with each other. This system is executed in the environment of Client/server architecture. Clients connect to the CAD sewer through Java applet on WWW. The server is implemented by Java application, and it consists of three components : connection manager which controls the contact to users, work manager which keeps viewing in concurrency and provides virtual work space sharing with others, and solid modeler which creates 3D object.

• KIPS Transactions on Computer and Communication Systems
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• v.10 no.8
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• pp.231-234
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• 2021

Various problems arise as applications using locations increase. In order to solve this problem, related works are being conducted to protect the location of users. A fundamental reason for this problem is that users must provide their location information to the service provider (server) to receive the service. To improve these problems, there are works such as generating cloaking regions or generating dummies around them. However, if a user periodically asks the server for queries, the user's trajectory may be exposed by time zone. To improve this problem, in this paper, we propose a k-Anonymity Trajectory (k-ATY) technique that can improve the exposure probability of the trajectory even if the user requests continuous queries. Experimental results demonstrated the superiority of the proposed technique.

• Korean Journal of Construction Engineering and Management
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• v.16 no.4
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• pp.118-128
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• 2015

Recently BIM technology has been expanded for using in construction project. Due to the high-cost of BIM infrastructure development, lack of regulations, lack of process and so forth, usage of BIM has been delayed than initial expectations. In design phase, especially, collaboration based on BIM system has been a key factor for successful next generation building project. Through the analysis of current research trends about IT technologies, virtualization and BIM service, data exchange such as drawings, 3D model, object data, properties using cloud computing and virtual server system is defined as a most successful solution. The purpose of this study is to enable the cloud computing BIM server to provide several main functions such as editing models, 3D model viewing and checking, mark-up and snapshot in high-performance quality by proper design of VDI system. Concurrent client connection performance is a main technical index of VDI. Through testing of test-bed server client, developed VDI system's multi-connect control is evaluated. Performance-test result of BIM server VDI effect to development direction of cloud computing BIM service for commercialization.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.236.2-236.2
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• 2014

세계 반도체 시장은 컴퓨터 기능이 더해진 모바일 기기의 수요가 증가함에 따라 메모리반도체의 시장규모가 최근 빠른 속도로 증가했다. 특히 모바일 기기에서 저장장치 역할을 하는 비휘발성 반도체인 NAND Flash Memory는 스마트폰 및 태블릿PC 등 휴대용 기기의 수요 증가, SSD (Solid State Drive)를 탑재한 PC의 수요 확대, 서버용 SSD시장의 활성화 등으로 연평균 18.9%의 성장을 보이고 있다. 이러한 경제적인 배경 속에서 NAND Flash 미세공정 기술의 마지막 단계로 여겨지는 1Xnm 공정이 개발되었다. 그러나 1Xnm Flash Memory의 생산은 새로운 제조설비 구축과 차세대 공정 기술의 적용으로 제조비용이 상승하는 단점이 있다. 이에 따라 제조공정기술을 미세화하지 않고 기존의 수평적 셀구조에서 수직적 셀구조로 설계 구조를 다양화하는 기술이 대두되고 있는데 이 중 Flash Memory의 대용량화와 수명 향상을 동시에 추구할 수 있는 3D NAND 기술이 주목을 받게 되면서 공정기술의 변화도 함께 대두되고 있다. 3D NAND 기술은 기존라인에서 전환하는데 드는 비용이 크지 않으며, 노광장비의 중요도가 축소되는 반면, 증착(Chemical Vapor Deposition) 및 식각공정(Etching)의 기술적 난이도와 스텝수가 증가한다. 이 중 V-NAND 3D 기술에서 사용하는 박막증착 공정의 경우 산화막과 질화막을 번갈아 증착하여 30layer 이상을 하나의 챔버 내에서 연속으로 증착한다. 다층막 증착 공정이 비정상적으로 진행되었을 경우, V-NAND Flash Memory를 제조하기 위한 후속공정에 영향을 미쳐 웨이퍼를 폐기해야 하는 손실을 초래할 수 있다. 본 연구에서는 V-NAND 다층막 증착공정 중에 다층막의 두께를 가상 계측하는 알고리즘을 개발하고자 하였다. 증착공정이 진행될수록 박막의 두께는 증가하여 커패시터 관점에서 변화가 생겨 RF 신호의 진폭과 위상의 변화가 생긴다는 점을 착안하여 증착 공정 중 PECVD 장비 RF matcher와 heater에서 RF 신호의 진폭과 위상을 실시간으로 측정하여 데이터를 수집하고, 박막의 두께와의 상관성을 분석하였다. 이 연구 결과를 토대로 V-NAND Flash memory 제조 품질향상 및 웨이퍼 손실 최소화를 실현하여 제조 시스템을 효율적으로 운영할 수 있는 효과를 기대할 수 있다.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.33 no.1
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• pp.87-97
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• 2023

Containers are an emerging virtualization technology that can build an isolated environment more lightweight and faster than existing virtual machines. For that reason, many organizations have recently adopted them for their services. Yet, the container architecture has also exposed many security problems since all containers share the same OS kernel. In this work, we focus on the fact that an attacker can abuse host resources to make them unavailable to benign containers-also known as host resource exhaustion attacks. Then, we analyze the impact of host resource exhaustion attacks through real attack scenarios exhausting critical host resources, such as CPU, memory, disk space, process ID, and sockets in Docker, the most popular container platform. We propose five attack scenarios performed in several different host environments and container images. The result shows that three of them put other containers in denial of service.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.05a
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• pp.608-611
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• 2012

In this paper, a mobile cloud-based agent model is proposed in order to overcome the resource constraints and the difficulties of installing a variety of complex applications in mobile devices. The proposed software architecture overcomes the disadvantages of mobile devices and maximizes usage of cloud services by implementing the function of mobile agent concept. The significant portion of the cloud services is run in the cloud server and the client application implemented in the mobile device can call and control appropriate service from the cloud server. Thus, the inherent weakness of the mobile can be overcome by executing the target applications on cloud nodes.

• The Journal of the Korea institute of electronic communication sciences
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• v.7 no.5
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• pp.1005-1010
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• 2012

The Augmented Reality, as a technology caught the spotlight as a next generation's technology of inserting 3D virtual objects in the space of reality seen through the camera, can maximize the learning effects by inducing user's absorption and interest using interaction between user and objects. Recently, as the movile devices having excellent mobility and portability are generalized, the diversified augmented reality are introduced using mobile devices. In this article, a 3D fish encyclopedia system augmented from the mobile environment was designed to provide the user with learning contents focusing on the sense of absorption and an interest. This system is intened to provide helps to learn about the fishes by recognizing the pictures of fishes in the encyclopedia as marker, bringing out the 3D model stored in server and displaying in the mobile environment.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.23 no.3
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• pp.491-500
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• 2013

With the advent of big data and increased costs of SSD(HDD), domestic and foreign Internet cafes and organizations have adopted NDS(No Disk System) solution recently. NDS is a storage virtualization solution based on a kind of cloud computing. It manages Operating System and applications in the central server, which were originally managed by individual computers. This research will illustrate the way to analyze user's behaviors under NDS circumstance.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.2
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• pp.253-261
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• 2005

The proposed internet disk for mobile devices is a new technique in order for mobile devices to recognize remote storage spaces as local storage card. The proposed technique is not to upload and download data of remote sites. It virtualizes remote storage space as local storage of mobile devices. Then mobile users can use the virtualized storage space as their local storage card. Also the remote storage space can be virtualized to desktop as local hard disk. It is possible to share data between mobile devices and desktop through the proposed internet disk.