• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.29 no.4C
• /
• pp.441-447
• /
• 2004

Information security simulator is required for the study on the cyber intrusion and defense as information security has been increasingly popular Until now, the main purposes of information security simulation are security estimation of small network as well as performance analysis of information protection systems. However, network simulators that can simulate attacks in a huge network are in needs since large scale internet attacks are very common in these days. In this paper we proposed a simulator design and its implementation details. Our simulator is implemented by expanding the SSFNet program to the client-sewer architecture. A cyber attack scenario used in our simulator is composed by the advanced attack tree model. We analyzed the simulation results to show the correctness of our network defense simulator.

• The Journal of Information Technology
• /
• v.1 no.1
• /
• pp.13-26
• /
• 1998

In general Information retrieval systems, improper keywords are often extracted and different search results are offered comparing to user's aim bacause the systems use only term frequency informations for selecting keywords and don't consider their meanings. It represents that improving precision is limited without considering semantics of keywords because recall ratio and precision have inverse proportion relation. In this paper, a system which is able to improve precision without decreasing recall ratio is designed and implemented, as client user module is introduced which can send feedbacks to server with user's intention. For this purpose, keywords are selected using relative term frequency and inverse document frequency and co-occurrence words are extracted from original documents. Then, the keywords are clustered by their semantics using calculated mutual informations. In this paper, the system can reject inappropriate documents using segmented semantic informations according to feedbacks from client user module. Consequently precision of the system is improved without decreasing recall ratio.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2022.11a
• /
• pp.321-322
• /
• 2022

In this study, the marine environment is measured and analyzed in real time through the X-band radar installed on the rooftop of the Sokcho Beach administrative Welfare Center and Ulleungdo. Afterwards, the goal is to transmit the analysis results to the client PC. Using electronic maps and electronic navigational charts, the measurement results are overlaid on GIS (spatial information system), real-time data are shared through a website, and information is displayed through a web server. Currently, CCTV information and marine environment information are displayed on the website, but various application studies such as the use of Open AP I will be conducted in the future.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.11 no.6
• /
• pp.2225-2233
• /
• 2010

Current puretone audiometer takes an operation model, so called face-to-face model, in which model an audiometrist assesses only one subject at a time. Such model results in high cost and long waiting time when there exist many patients. In order to solve such a disadvantage of face-to-face model, we have developed PC-based audiometer supporting client/server model, in which model one audiometrist is able to measure several subjects concurrently. This model has an architecture like that several PCs for subjects are connected to an audiometrist's PC through LAN and each assessment process of subjects are displayed onto audiometrist's monitor in real time. And if necessary, it makes possible for audometrist to adjust the assessment progress of particular subject like as a face to face model.

• Journal of Broadcast Engineering
• /
• v.22 no.4
• /
• pp.509-518
• /
• 2017

High-resolution digital holograms can be quickly generated by using a PC cluster that is based on server-client architecture and is composed of several GPU-equipped PCs. However, the data transmission time between PCs becomes a large obstacle for fast generation of video holograms because it linearly increases in proportion to the number of frames. To resolve the problem with the increase of data transmission time, this paper proposes a multi-threading-based method. Hologram generation in each client PC basically consists of three processes: acquisition of light sources, CGH operation using GPUs, and transmission of the result to the server PC. Unlike the previous method that sequentially executes the processes, the proposed method executes in parallel them by multi-threading and thus can significantly reduce the proportion of the data transmission time to the total hologram generation time. Through experiments, it was confirmed that the total generation time of a high-resolution video hologram with 150 frames can be reduced by about 30%.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.12 no.6
• /
• pp.2895-2921
• /
• 2018

Security has become one of the major concerns in mobile adhoc networks (MANETs). Data and voice communication amongst roaming battlefield entities (such as platoon of soldiers, inter-battlefield tanks and military aircrafts) served by MANETs throw several challenges. It requires complex securing strategy to address threats such as unauthorized network access, man in the middle attacks, denial of service etc., to provide highly reliable communication amongst the nodes. Intrusion Detection and Prevention System (IDPS) undoubtedly is a crucial ingredient to address these threats. IDPS in MANET is managed by Command Control Communication and Intelligence (C3I) system. It consists of networked computers in the tactical battle area that facilitates comprehensive situation awareness by the commanders for timely and optimum decision-making. Key issue in such IDPS mechanism is lack of Smart Learning Engine. We propose a novel behavioral based "Smart Multi-Instance Multi-Label Intrusion Detection and Prevention System (MIML-IDPS)" that follows a distributed and centralized architecture to support a Robust C3I System. This protocol is deployed in a virtually clustered non-uniform network topology with dynamic election of several virtual head nodes acting as a client Intrusion Detection agent connected to a centralized server IDPS located at Command and Control Center. Distributed virtual client nodes serve as the intelligent decision processing unit and centralized IDPS server act as a Smart MIML decision making unit. Simulation and experimental analysis shows the proposed protocol exhibits computational intelligence with counter attacks, efficient memory utilization, classification accuracy and decision convergence in securing C3I System in a Tactical Battlefield environment.

• Journal of Korea Multimedia Society
• /
• v.2 no.3
• /
• pp.265-276
• /
• 1999

Video on Demand (VOD) system is definitely one of main applications in upcoming multimedia era. In this research, we have designed and implemented a host-based scalable VOD system (SVOD) which is composed of low cost PC servers and runs on Linux kernel that is currently spotlighted in enterprise and research domains. Our contribution is as follows: first, the previous Ext2 file system was modified to efficiently support continuous media like MPEG stream. Second, the storage server features a host-based scalable architecture. Third, a software MPEG decoder was implemented using Microsoft's DirectShow$\circledR$COM. Finally, flow control between client and server is provided to suppress overflow and underflow of client circular buffer and supports FF VCR operation. We have known that it is possible to develop a thread-based and scalable VOD system on low cost PC servers and free Linux kernel.

• The KIPS Transactions:PartD
• /
• v.10D no.3
• /
• pp.359-366
• /
• 2003

Although the reuse of the cached data for scrolling the map reduces the amount of passed data between client and server, it needs the conversions of data coordinates, selective deletion of objects, cache compaction and object structuring step in the clients. The conversion is a time- intensive operation due to limited resources of mobile phones such as low computing power, small memory. Therefore, in order to control the map efficiently in the vector map service based mobile phones, it is necessary to study the methods which reuse cached objects for reducing wireless network bandwidth and overwhelming the limited resources of mobile phones as well. This paper proposes the methods of reusing pre-received spatial objects for map control in the mobile vector map service system based on client-server architecture. The experiments conducted on the Web GIS systems with real data show that the proposed method is appropriate to map services for mobile phone. We also analyze the advantages and drawbacks between the reuse of cached data and transmission of raw data respectively.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.13 no.6
• /
• pp.37-45
• /
• 2013

In this paper proposes the latest network-assisted online telemedicine service to coincide with the point being discussed for health care providers to match patients, patients with personalized medical service support system. In order to design the system, to understand the requirements of the patient personalized medical support service system, the data were normalized and were designed architecture client server structure. Further, in order to implement the system that was designed to define the structure of server and client, ontology repository, we implement the system. In this paper, as a result of the test by creating a scenario and prerequisites for testing patient personalized medical service support system that is design and implementation, selecting a patient's condition, department of symptoms by the selected but it was confirmed that the inference is, inference medical institutions that fits department inferred one following upon the items medical patient has the required.

• Journal of KIISE:Information Networking
• /
• v.32 no.1
• /
• pp.80-88
• /
• 2005

In ubiquitous spaces, a user wants to be provided with a VOD service while moving one space to another freely. Since the traditional VOD system is dependent on user location, the VOD server transmits video data to a single client during a session. If the user moves to another space, he/she should close the old session and make a new request for the same video. However, the location-aware VOD system supports user mobility by closing and opening the session automatically. That is, the VOD system automatically perceives the movement of a user and allows the server to change the data flow so that a client near the user can receive the video data. This paper proposes a location-aware VOD service architecture and a session handoff scheme to provide a mobile user with continuous video delivery and implements a location-aware VOD prototype system based on Jini and Java. In experiment, we show that the proposed handoff scheme has a smaller handoff delay than the other handoff scheme.