• Annual Conference of KIPS
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• 2002.11c
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• pp.2435-2438
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• 2002

본 논문은 다양한 표준의 제어 미들웨어가 설치된 환경에서 흠내의 정보기기간의 정보 전달 및 제어물 위해서 단일한 서비스를 개발, 실행하기 위한 구조를 설명한다. 기존의 가전제품에 다양한 통신 미디어(예: IEEE1394, IrDA, LAM, PLC, Bluetooth 등)이 추가되어 새로운 부가가치를 지원하는 정보가전제품들이 소개되고 있고 이에 적합한 통신 환경이 개발, 보급되고 있다. 또한, 정보기기간의 제어, 데이터 전송, 서비스 개발을 목적으로 다양한 제어 미들웨어(Jini, HAVi, LonWorks, UpnP 등) 이 제시되고 발전해가고 있다. 이러한 추세에 의하면 향후 수년안에 홈네트워크 서비스 플랫폼의 요구사항이 높아지며 특히, 다중 제어 미들웨어를 지원하는 서비스 플랫폼의 등장이 필요한 시점이다. 본 논문에서 설계, 구현한 홈네트워크 통합미들웨어는 서비스 프로바이더(서비스 제공자 및 운용자)에게 서비스개발, 보급 운용의 단일 환경을 제공한다. 이의 한 예제인 홈네트워크 미들웨어 연동 서비스는 서로 다른 제어 미들웨어를 따르는 정보기기간의 연동 서비스를 다양한 매체를 수용하는 홈서버에서 가능하도록 구축하였다.

• Convergence Security Journal
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• v.17 no.3
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• pp.3-9
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• 2017

NFV is a technology that allows network services to be controlled and managed in software by separating various net work functions (NFs) from hardware devices in dedicated network equipment and implementing them in a high-performance general-purpose server. Therefore, standardized virtualization of network functions is one of the most important factors. However, until the introduction of NFV to provide commercial services, there are many technical issues to be solved such as guaranteeing performance, stability, support for multi-vendor environment, ensuring perfect interoperability, and linking existing virtual and non-virtual resources. In this paper, we propose a method to provide an end-to-end network virtualization service based on OSM R2 in KREONET.

• Journal of Korean Elementary Science Education
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• v.25 no.3
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• pp.271-280
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• 2006

In this paper, an Online Scientific Inquiry Learning System was developed with the aim of improving student's scientific literacy and scientific inquiry ability. It was determined that there should be 4 distinct principles applicable to the design of the Learning system. First, it should enrich learner's motivation. Second, it should provide students with the chance for reflecting on the inquiry process. Third, it should emphasize multi-dimensional forms of interaction. Fourth, students should be able to create new information through it. The server system including the database, equation editor, reporting tool, search engine were all utilized for developing the learning system. In addition, the authors produced 24 web-based projects which were guided inquiry activities in which various inquiry abilities (reasoning, prediction, experiment design) could be developed. An Online Scientific Inquiry Learning System is not the only program which could be utilized in improving scientific inquiry abilities, but at the very least, such a system can serve as the prototype for developing an online learning system.

• Journal of Ocean Engineering and Technology
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• v.19 no.6 s.67
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• pp.86-91
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• 2005

Regarding some of tire important works in tire shipyard, like tire production process, quality control, and material handling, there are many elements that disturb tire work-flaw. For example, there are mistakes in manufacturing, delay of production, and poor quality. These kinds of disturbances are from tire delay of communication time between tire production field and tire management. Therefore, it would be possible to strengthen tire competitiveness of shipbuilding industries by applying tire information technology based on Wireless Local Area Network (Wireless LAN), in order to establish tire multi-possession of real time production information in limited large shipbuilding yard. In this study, tire construction concept of tire information system, based on Wireless LAN, is proposed to build communication infrastructures in shipyards. The various information regarding shipbuilding inspection, process management, and material flaw are analyzed and constructed to databases in tire middle ware system, as tire platform for using Personal Display Agent (PDA). At last, tire middle ware system, which delivers tire information, is developed by tire C$\sharp$ and Microsoft.net; also, tire PDA application system is structured in WinCE O/S, and is tested and evaluated under tire server linked condition.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.39 no.6
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• pp.603-610
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• 2015

This paper presents a multimodal sensor system that can determine the location of house space by analyzing the postures and heights of the residents. It consists of two sensors: a tilt sensor and an altimeter sensor. The tilt sensor measures the static and dynamic postures of the residents, and the altimeter sensor measures their heights. The sensor system includes a Bluetooth transmitter, and the server receives the measured data and determines the location in the house. We describe the process determining the locations of the residents after analyzing their postures and behaviors from the measured data. We also demonstrate the usefulness of the proposed system by applying it to a real environment.

• Journal of Korean Society for Geospatial Information Science
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• v.5 no.2 s.10
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• pp.193-205
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• 1997

It is required for multi-users to share massive mapping data effectively that distributed data model in the Client-Server environment is developed for the replication consistency. The existing model is not effective to the long transaction just like a mapping system, since it does not account lot consistency between GUI screen and database replications even though it emphasizes on the replication consistency. The performance of concurrency control is very important for those long transactions, especially the mapping systems. This model is to support consistency between GUI screen and replicas using display locks. It suggests consistency model improving process performance by modifying memory consistency model and optimistic concurrency control for mapping data's characteristics.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.10C
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• pp.956-963
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• 2006

This research studies multi participant consistency and dynamic data shared through 3D scenes in virtual network environments. In a distributed virtual environment of client-server structure, consistency is maintained by the static information exchange; as jerks occur by packet delay when updating messages of dynamic data exchanges are broadcasted frequence, the network bottleneck is reduced by predicting the movement path by using the Dead-reckoning algorithm. In Dynamic data path prediction, the tests the location prediction error between Dead-reckoning convergence interval and error of prediction and actual condition one time above threshold it interpolates a previously location. The shared dynamic data of the 3D virtual environment is implementation using the VRML EAI.

• Journal of Information Technology Services
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• v.7 no.2
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• pp.137-148
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• 2008

This paper measures and compares the traffic of a series of Massively Multi-player On-line Role Playing Game (MMORPG). The purpose of this analysis is to characterize the MMORPG traffic and compare the traffic characteristics of those games caused by the game structure difference between 2D and 3D environment. The target game is 'Lineage I' and 'Lineage II' which represent world's largest MMORPGs in terms of the number of concurrent users. We collect about 280 giga bytes and 1 tera bytes of packet headers, respectively. We compare packet size, packet inter-arrival time and bandwidth usage of these two games. The MMORPG traffic consists of two kinds of packets: client-generated upstream packets and server-generated downstream packets. We observe that the upstream packet size of payload has grown from 9 bytes to 19 bytes, while the average payload size of downstream packets has grown from 37 bytes to 318 bytes. This asymmetry of growing rate is caused by 3D game structure. Packet inter-arrival time becomes shorter from average 2 milliseconds to 58 microseconds. Bandwidth consumption per client has grown from 4 kbps to 20 kbps. We find that there is a linear relationship between the number of users and the bandwidth usage in both case.

• Journal of Korea Game Society
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• v.5 no.4
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• pp.33-38
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• 2005

In the online game that thousands of participants connect to a game world by using Internet simultaneously, participants of the game world may have different hardwares and network environments, and messages of participants should be synchronization. A solution for the synchronization problem is to wait for a certain amount of time until the server processes the message. It is not easy to determine a suitable waiting period because of the trade-off between the fairness and the responsiveness. In this paper we propose a method to decide a waiting period by considering features of the MMOFPS game and the probability of interaction among participants. We implement the proposed method and perform experiments for the performance evaluation.

• Journal of Communications and Networks
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• v.13 no.2
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• pp.160-166
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• 2011

In u-healthcare services based on wireless body sensor networks, reliable connection is very important as many types of information, including vital signals, are transmitted through the networks. The transmit power requirements are very stringent in the case of in-body networks for implant communication. Furthermore, the wireless link in an in-body environment has a high degree of path loss (e.g., the path loss exponent is around 6.2 for deep tissue). Because of such inherently bad settings of the communication nodes, a multi-hop network topology is preferred in order to meet the transmit power requirements and to increase the battery lifetime of sensor nodes. This will ensure that the live body of a patient receiving the healthcare service has a reduced level of specific absorption ratio (SAR) when exposed to long-lasting radiation. We propose an efficientmethod for delivering delay-intolerant data packets over multiple hops. We consider forward error correction (FEC) in an erasure correction mode and develop a mathematical formulation for packet-level scheduling of delay-intolerant FEC packets over multiple hops. The proposed method can be used as a simple guideline for applications to setting up a topology for a medical body sensor network of each individual patient, which is connected to a remote server for u-healthcare service applications.