• The Journal of the Korea Contents Association
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• v.1 no.1
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• pp.109-117
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• 2001

The WAP gateway. for wireless internet applications services, is a software that is placed between the user terminals(PDA, mobile phones) and the WAP/Web server. H is a middleware system that converts the protocol of a packet network to the protocol on the WAP network, and supports the encoding of WML documents. In this paper, we designed and implemented the WAP gateway based on the WAP specification version 1.2 announced by the WAP forum. It provides cross-platform compatibility by being implemented by the Java language. Compared with a Kannel system using a Nokia tool kit version 1.2, it provides a more excellent performance and a stability.

• The KIPS Transactions:PartD
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• v.8D no.1
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• pp.1-9
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• 2001

The SQL CLl (Call Level Interface) is a database application programming interface (API) that fits the client-server environment, and its de facto standards such as ODBC and JDBC are widely employed in various applications. The current SQL CLl standards, however, do not specify enough features for efficient retrieval of large objects (LOBs) that constitute the multimedia data. In this paper, we propose the LOB caching through the SQL CLl and describe the extension of the SQL eLl to achieve such a goal. We implement our proposal by extending the SQL CLl library for BADA - II DBMS developed at ETRI, and evaluate the performance of LOB retrieval through the cache compared to that of LOB retrieval conducted solely with the functions specified in the current SQL CLl standards.

• Journal of Computing Science and Engineering
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• v.5 no.4
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• pp.331-337
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• 2011

Recently, Virtual Desktop Infrastructure (VDI) has been widely adopted to ensure secure protection of enterprise data and provide users with a centrally managed execution environment. However, user experiences may be restricted due to the limited functionalities of thin clients in VDI. If thick client devices like laptops are used, then data leakage may be possible due to malicious software installed in thick client mobile devices. In this paper, we present Data Firewall, a security framework to manage and protect security-sensitive data in thick client mobile devices. Data Firewall consists of three components: Virtual Machine (VM) image management, client VM integrity attestation, and key management for Protected Storage. There are two types of execution VMs managed by Data Firewall: Normal VM and Secure VM. In Normal VM, a user can execute any applications installed in the laptop in the same manner as before. A user can access security-sensitive data only in the Secure VM, for which the integrity should be checked prior to access being granted. All the security-sensitive data are stored in the space called Protected Storage for which the access keys are managed by Data Firewall. Key management and exchange between client and server are handled via Trusted Platform Module (TPM) in the framework. We have analyzed the security characteristics and built a prototype to show the performance overhead of the proposed framework.

• Korean Journal of Artificial Intelligence
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• v.1 no.1
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• pp.4-6
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• 2013

In the era of information society, IT industry has been developed very much. New technology has made appearance in citizens' lives. IOT (Internet of Things) has grown up the most rapidly in IT industry. Kevin Ashiton, MIT specialist, said, "Loading of FRIS and other sensors shall build Internet of things." Internet of things is said to let things have sensor and communication module and to exchange information and communicate each other. In this study, Internet of things has been applied to flowerpot to build automatic flowerpot control system that turns fan ON and supplies water depending upon temperature and moisture. Users are difficult to cognize temperature and humidity of flower pot correctly. In this study, an experiment obtained correct value of temperature and humidity to build control system. At the performance test of flower pot, commands turned ON depending upon temperature and humidity. Control system should be added to control water supply quantity and time objectively according to servo motor control. Purpose of further study was to control flower pot by remote system in connection with smart phone application. An application control can make not only temperature and humidity statistics but also server depending upon users' needs to turn fan ON and take actions and to control flower pot.

• IEMEK Journal of Embedded Systems and Applications
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• v.1 no.2
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• pp.90-103
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• 2006

There are many file systems in various operating systems. Those are usually designed for server environments, where the common cases are usually 'multiple active users', 'great many small files' And they assume a big main memory to be used as buffer cache. So the existing file systems are not suitable for resource hungry embedded systems that process multimedia data streams. In this study, we designed and implemented a new file system which efficiently stores and retrieves multimedia data steams. The proposed file system has a very simple disk layout, which guarantees a quick disk initialization and file system recovery. And we introduced a new indexing-scheme, called the time-based indexing scheme, with the file system. With the indexing scheme, the file system maintains the relation between time and the location for all the multimedia streams. The scheme is useful in searching and playing the compressed multimedia streams by locating exact frame position with given time, resulting in reduction of CPU processing and power consumption. The proposed file system and its APIs utilizing the time-based indexing schemes were implemented firstly on a Linux environment, though it is operating system independent. In the performance evaluation on a real DVR system, which measured the execution time of multi-threaded reading and writing, we found the proposed file system is maximum 38.7% faster than EXT2 file system.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.10 no.2
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• pp.13-18
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• 2010

Today, The much amount of spam that occupies the mail server and network storage occurs the lack of negative issues, such as overload, and for users to delete the spam should spend time, resources have a problem. Automatic spam filtering on the incidence to solve the problem is essential. A lot of Spam filters have tried to solve the problem emerged as an essential element automatically. Unlike traditional method such as Naive Bayesian, PCA through the many-dimensional data set of spam with a few spindle-dimensional process that narrowed the operation to reduce the burden on certain groups for classification Logistic regression analysis method was used to filter the spam. Through the speed and performance, it was able to get the positive results.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.14 no.2
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• pp.59-64
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• 2014

This paper address the scheme for WiMAX backhaul in mobile communication network. These days most ISPs has implemented Wi-Fi backhaul using T1/E1 and DSL. if WiMAX is installed as the alternative to the mobile backhaul, it can decrease the costs drastically for the installation and operations. And it will be one of the best cost-effective solutions to cover the service areas which has not the wired communication infrastructure. WiMAX can be used for Base station, Subscriber Station, and Relay. In this paper, the performance is measured for downstream and upstream using NAT and port forwarding functions by configuring WiMAX server and WiMAX SS.

• The KIPS Transactions:PartC
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• v.12C no.7 s.103
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• pp.973-980
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• 2005

This paper proposes the more various key generation algorithms than existing method and the DRM encryption system supporting the higher security than the existing systems which do not store a symmetric key made by the key generation algorithm in a server. Also, we propose a client security agent system which decrypts a data by analogized key. We designed and implemented the proposed system And, we tested the video data files with the various sizes to evaluate the performance of our system Our experiment results show that the delay time which includes an encryption and decryption time was significantly reduced through our proposed scheme.

• The Transactions of the Korea Information Processing Society
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• v.3 no.5
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• pp.1198-1206
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• 1996

This paper proposes the functionality of communication network management which operates in central control station of satellite communication network, which will be constructed to DAMA-SCPC ground station using KORE ASAT. And communication network configuration components are classified with hierarchical structure in order to efficiently maintain communication network operation management, and configuration components that are classified into graphic objects and this graphic objects are visualized with tree structure which can be handled uniformally and efficiently. In addition to that, this paper proposes expression method of graphic object to implement our real time communication network management system, and the real time communication net-work management composed as client-server system. The performance of the proposed algorithm is analyzed through the computer simulation.

• 한국정보디스플레이학회:학술대회논문집
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• 2005.07b
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• pp.1611-1614
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• 2005

In this paper, a new multi-view 3D video communication system for real-time Reality teleconferencing application is proposed by usin gthe IEEE 1394 digital cameras, Intel Xeon server computer system and Microsoft's DirectShow programming library and its performance is analyzed in terms of image-grabbing frame rate and number of views. The captured two-view image data is compressed by extraction of disparity data between them and transmitted to another client system through the communication network, in which multi-view could be synthesized with this received 2-view data using the intermediate view reconstruction technique and displayed on the multi-view 3D display system. From some experimental results, it is found that the proposed system can display 16-view 3D images with a gray of 8bits and a frame rate of 15fps.