• Journal of Mechanical Science and Technology
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• v.20 no.4
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• pp.455-466
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• 2006

This study was an attempt to control and monitor Computerized Numerical Controller (CNC) machines anywhere and anytime for the development of a ubiquitous machine (u-machine). With a Personal Digital Assistant (PDA) phone, the machine status and machining data of CNC machines can be monitored in wired and wireless environments, including the environments of IMT2000 and Wireless LAN. Moreover, CNC machines can be controlled anywhere and anytime. The concept of the anywhere-anytime controlling and monitoring of a manufacturing system was implemented in this study for the purpose of u-manufacturing and u-machines. In this concept, the communication between the CNC controller and the PDA phone was successfully performed anywhere and anytime for the real-time monitoring and control of CNC machines. In addition, the interface between the CNC controller and the developed application module was implemented by Object linking and embedding for Process Control (OPC) and shared CNC memory. For communication, the design of a server contents module within the target CNC was based on a TCP/IP. Furthermore, the client contents module within the PDA phone was designed with the aid of embedded c++ programming for mobile communication. For the interface, the monitoring data, such as the machine status, the machine running state, the name of the Numerical Control (NC) program, the alarm and the position of the stage axes, were acquired in real time from real machines with the aid of the OPC method and by sharing the CNC memory. The control data, such as the start, hold, emergency stop, reserved start and reserved stop, were also applied to the CNC domain of the real machine. CNC machines can therefore be controlled and monitored in real time, anywhere and anytime. Moreover, prompt notification from CNC machines to mobile phones, including cellular phones and PDA phones, can be automatically realized in emergencies.

• Journal of the Korean Association of Geographic Information Studies
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• v.11 no.1
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• pp.10-19
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• 2008

This study designed and implemented a J2ME based on mapping viewer to browse the SVG based wireless-map in mobile phone. This proposed technique was efficiently applied to a forest fire extinguishment information management system by mapping the exact location of important objects on wireless-map in wireless network. As the result, the study helps to guide the safe and efficient extinguishment affairs and provides the safe extinguishment environment for ground fire fighting teams in real time. And also this technique presents the way to move the client mapping function such as representation of the moving coordinates to server and made it possible to operate SVG based viewer in personal cellular phone.

• Journal of Korea Multimedia Society
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• v.14 no.7
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• pp.849-857
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• 2011

Gaming on demand(GOD) makes people enjoy games by encoding and transmitting game screen at a server side, and decoding the video at a client side. In this paper, we propose a fast game video encoder for multiple users over network with low-powered devices. In the proposed system, the computational complexity of game encoders is reduced by using scene descriptors, which consists of an object motion vector, global motion, and scene change. With additional information from game engines, the proposed encoder does not need to perform various complexity processes such as motion estimation and ratedistortion optimization. The motion estimation and rate-distortion optimization skipped by scene descriptors. We found that the proposed method improved 192 % in terms of FPS, compared with x264 software. With partial assembly code, we also improved coding speed by 86 % in terms of FPS. We found that the proposed fast encoder could encode over 60 FPS for real-time GOD applications.

• Journal of Advanced Navigation Technology
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• v.17 no.1
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• pp.24-32
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• 2013

Authentication is one of the necessary elements in the network environment. Many researches have detected security vulnerabilities to the existing authentication mechanisms and suggested secure mutual authentication protocols by resolving these vulnerabilities. The representative ones of them are SPMA(Strong Pass Mutual Authentication) and I-SPMA(Improved Strong Password Mutual Authentication). However, these protocols cause a critical problem when the shared secret information is de-synchronized between the server and the client. This paper proposes a revised protocol to resolve the de-synchronization problem. Based on a security assessment on the proposed protocol, we consider the proposed protocol is safer than the previous ones and possible to effectively make a user authentication system mre secure.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2003.05a
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• pp.560-563
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• 2003

In this paper describes for use Authentication with the WPKI and Kerberos protocol. this paper is the security structure that defined in a WAP forum and security and watches all kinds of password related technology related to the existing authentication system. It looks up weakness point on security with a problem on the design that uses wireless public key-based structure and transmission hierarchical security back of a WAP forum, and a server-client holds for user authentication of an application level all and all, and it provides one counterproposal. Therefore, We offer authentication way solution that connected X.509 with using WIM for complement an authentication protocol Kerberos and its disadvantages.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.6 no.11
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• pp.2920-2939
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• 2012

Enterprises that develop online games have to deploy supporting infrastructures, including hardware and bandwidth resources, in order to provide a good service to users. First Person Shooter games generate high rates of small UDP packets from the client to the server, so the overhead is significant. This work analyzes a method that saves bandwidth, by the addition of a local agent which queues packets, compresses headers and uses a tunnel to send a number of packets within a multiplexed packet. The behavior of the system has been studied, showing that significant bandwidth savings can be achieved. For certain titles, up to 38% of the bandwidth can be saved for IPv4. This percentage increases to 54% for IPv6, as this protocol has a bigger overhead. The cost of these bandwidth savings is the addition of a new delay, which has an upper bound that can be modified. So there is a tradeoff: the greater the added delays, the greater the bandwidth savings. Significant reductions in the amounts of packets per second generated can also be obtained. Tests have been deployed in an emulated scenario matching an access network, showing that if the number of players is big enough, the added delays can be acceptable in terms of user experience.

• Journal of Korea Multimedia Society
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• v.7 no.3
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• pp.377-387
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• 2004

This paper describes a tree-based conversational interface supporting efficient presentation of turn relations on online conversation. Most of conventional conversational interfaces are difficult to make use of formal conversation such as group meeting, decision-making, etc. due to very simplicity of a con versational interface and restriction of data structure of conversational messages. And a tree-based conversational interface supports formal conversation, but they are difficult to present turn relations because of jumpy display by locations of replied turns and distance between replied turns, etc. So this paper suggests a tree-based conversational interface to present efficiently turn relations using XML-based messages with merits of a text-based interface. The suggested conversational interface was implemented by using XML-, DOM, and JDK. And this paper showed that the conversational interface could be applied to conversation system using client- server architecture. Applications for the conversational interface are as follows: collaboration, distance teaming, online game, etc.

• The Journal of the Korea Contents Association
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• v.6 no.10
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• pp.126-133
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• 2006

Application software streaming is a virtualization technology that enables users to use applications without installation on her/his computer. With application streaming service, a client immediately starts and uses the application as if it were installed. The application can be executed while executable codes for the application may still be streamed. Since the software streaming is based on networks, its service is affected by network failures. Network failures may cause the streamed application to stop, and to make it worse, also the system may crash because executable codes for the application can't be streamed from the streaming server. Using the Pareto principle (80 vs. 20 rule), users can be served continuously with the minimum functions that are frequently used, pre-fetched and cached if we provide a more intelligent and fault-tolerant streaming technique. This paper proposes the concept and technique named Evergreen. Using the Evergreen technique, users can continue using the streamed application while a network failure occurs, although user can access only the streamed code. We also discuss the implementation of Evergreen technique in details.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.06a
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• pp.649-652
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• 2007

Recently, it is increasing the interest in previous web and web 2.0 which mean differentiation. The previous system is typical Static web based on client and server model, while web 2.0 mean next generation web which web change and evolve fundamentally. In this paper, I suggest that the module on RSS reader available under web 2.0 standards. A currently used RSS feed do correct the part distortion which can be possible resolve the encoding problem of Hanguel and third-world language. The suggested module is implemented using Ajax. I developed the module for the use of effective contents on web 2.0 through the DragBox module based on the programming on mobility of Ajax and the design and implementation of automatic update module of RSS feed.

• Proceedings of the Korea Water Resources Association Conference
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• 2008.05a
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• pp.1823-1827
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• 2008

신뢰성 있는 수문자료는 홍수와 가뭄의 피해를 경감하기 위한 각종 수공구조물의 설계 및 기준 수립에 필요한 기초적인 자료이다. 또한, 국내 수문특성을 대변할 수 있는 고품질 수문자료의 확보는 경제 산업적으로도 필수적이고 기본적인 사항이다. 이러한 여건들과 사회적인 요구에 부응하기 위해서는 적극적인 품질관리를 통해 신뢰성 있는 수문자료를 제공해야 한다. 수문자료의 중요성과 수문자료 품질관리의 필요성이 대두되고 있는 사회적인 요구를 반영하고자 국가 수문자료 품질관리 기준을 제시하고 현업에 적용 가능한 시스템을 구축하여 수문자료 관리 체계를 확고히 함으로써 수문자료 신뢰성을 확보하는 데 본 연구의 목적이 있다. 한강홍수통제소 관할 수문관측소의 실시간 수문자료(우량, 수위)에 대해 기왕자료 분석을 통해 지점별 이상치 자동점검 기준을 설정하였고 이에 따른 자동 품질관리를 거친 후 이상 및 결측치를 수동으로 수정, 보완할 수 있는 기법을 적용하여 수동 품질관리를 수행할 수 있도록 C/S(Client/Server) 방식의 전산프로그램을 개발하였다. 본 연구에서 구축된 국가 수문자료 품질관리시스템에 의해 수행된 품질관리 과정을 통해 수정, 보완된 자료는 원시자료, 자동품질등급, 수정자료, 수동품질등급의 자료 품질 표지가 이루어지고, 자료의 현황을 자세히 알 수 있도록 구성되었다. 국가 수문자료 품질관리시스템을 통해 수문자료 품질관리업무의 효율성을 증대시키고 수문자료의 신뢰도를 높이는 수단으로 활용될 것이다.