• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.32 no.8B
• /
• pp.473-481
• /
• 2007

We are interested in the PON which is easy to install and inexpensive to maintain, as it is a solution of the FTTH that is a core technology of the BcN access network. When a new ONU is connected, TDMA PON has a procedure called ranging that OLT measures the distance and allocates the equalized delay to it in order to provide the same logical distance to all ONUs. For the procedure, the OLT has to open a time window several times and already activated ONUs cannot transmit a data to the upstream during the periods. Accordingly, it is important to reduce the window size for saving the bandwidth and providing a user the service smoothly. In this paper, we investigate the ONU activation method of G-PON based on ITU-T G984.3 and suggest an advanced method(algorithm I) that minimizes the window size without information of ONU distance. The size can be reduced by calculating the pre-assigned delay obtained during Serial number state. Also, we compare it with another(algorithm II) with information of distance. As a result, the window size reduces to $50{\sim}90%$ for the algorithm I and 99% for algorithm II during the ONU activation process.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.14 no.3
• /
• pp.603-612
• /
• 2010

Recently, with the advance of computing and networking technique, the high speed internet becomes widespread, however, it is still hard job to do streaming the media which requires high network bandwidth over the internet. Previous VoD system researches for streaming over the internet mainly proposed techniques that controls the QoS(Quality of Service) of the media in proportion to the network status. Though, this could be the solution for the service provider while the service user who wants constant QoS may not satisfy with variable QoS. In the paper, we propose greedy precedent frame transmission technique, GPFT, for guarantee of constant QoS. In GPFT, Streaming VoD server prefetches precedent frames and transmits the frame greedily by increasing the frame transmission rate while the available network bandwidth is high. The GPFT uses the prefetched precedent frames to guarantee the QoS while the available network bandwidth is low. The experiment result shows that the proposed GPFT could guarantee the constant QoS by prefetching the frames adaptively to the network bandwidth with the characteristic of video stream.

• Journal of the Korean Society for information Management
• /
• v.19 no.1
• /
• pp.23-46
• /
• 2002

With explosively increasing digital contents, library and Information center should have a new role between knowledge providers and knowledge users as information brokering organization. Electronic transaction system should be required for performing this brokering service since economic value is added to information and knowledge in information society. The developments and changes around library are keeping up with increasing building digital library and digitalizing printed sources. With the rapidly changing circumstances, the Internet is currently witnessing an explosive growth. By serving as a virtual information resource. the Internet can dramatically change the way business is conducted and Information is provided. However because of features o( the Internet like openness and information sharing, it has fundamental vulnerabilities in security issues. For Instance, disclosure of private information and line eavesdropping such as password, banking account, transaction data on network and so on are primary obstruction factors to activation of digital contents delivery on network. For high network security and authentication, this paper looks at smart card technologies and proposes multi-authentication protocol based on smart card on open network, implements and analyzes it.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.38C no.10
• /
• pp.867-873
• /
• 2013

Competition policy for growth and activation of market should consider structural nature of relevant industry closely. In this viewpoint, whether domestic MNOs(mobile network operators) are competing while securing the effect of scale economies and maximum production efficiency is an important element when looking for competition policy means of domestic mobile communication market. With this, present study analyzed level of MES (Minimum Efficient Scale) and whether achieving them or not through investigating the relation between the cost per minute and call traffic of domestic MNOs. This analysis is differentiated from existing econometric studies entailing several assumptions by enhancing a reality reflection through directly deducing of cost curve using verified data(cost per minute and call traffic). As a result of analysis, the levels of minimum efficient scale were different from each other between domestic MNOs, and an incumbent MNO(SKT) accomplished minimum efficient scale while entrant MNOs(KT and LGU+) could not yet reach minimum efficient scale level. This result demonstrates a gap exists in production efficiency level among domestic MNOs and implies that the policy to alleviate the gap among operators is required when establishing competitive policy in the future.

• Journal of Korean Society of Archives and Records Management
• /
• v.4 no.2
• /
• pp.76-90
• /
• 2004

There had been substantial demand for record management system with which to efficiently control the information circulation processes, involving accumulation of recorded materials, classification of information resources, and users access to them. It converged to a collaboration of Australian federation, and Sydney Records Centre and finally induced Australian Standard Records Management, commonly known as AS 4390. AS 4390 served later as a model for International Standard of Record Management. This paper introduces the current undertaking of Recordkeeping system development in Australia, which stems from the line of AS 4390 by analysing exhibited research approaches. The analysis includes the definition, regime of Recordkeeping system, design and implementing of guidelines of Recordkeeping System and information on metadata projects. It also highlights the necessity for standardization, as is the prime factor in promoting inter-linking of Tabularium on New Southwales State, CRS(Commonwealth Record Series), database system of Canberra National Archives and Australian Government Locator Service. From year 2005, as dictates, any record management system, serving public agency will be required to adapt Professional Archives Management System, which, by far, will enhance the inter-compatibility. In its application, the government need Thesaurus to eliminate possible redundancy in use of terminology and to promote correct usage of words.

• Journal of the Korea Institute of Information Security & Cryptology
• /
• v.25 no.6
• /
• pp.1465-1475
• /
• 2015

Cheating detection models in the online games can be divided into two parts. The one is on client based model, which is designed to detect malicious programs not to be run while playing the games. The other one is server based model, which distinguishes the difference between benign users and cheaters by the server log analysis. The client based model provides various features to prevent games from cheating, For instance, Anti-reversing, memory manipulation and so on. However, being deployed and operated on the client side is a huge weak point as cheaters can analyze and bypass the detection features. That Is why the server based model is an emerging way to detect cheating users in online games. But the simple log data such as FPS's one can be hard to find validate difference between two of them. In this paper, In order to compensate for the disadvantages of the two detection model above, We use the existing game security solution log as well as the server one to bring high performance as well as detection ratio compared to the existing detection models in the market.

• Proceedings of the Korea Contents Association Conference
• /
• 2006.11a
• /
• pp.555-559
• /
• 2006

This paper will intend to contribute to extracting and storing various form of information on user interests by using structural rules user makes and XML-based word document converting techniques. The system named PPE consists of three essential element. One is converting element which converts word documents like HWP, DOC into XML documents, another is extracting element to prepare structural rules and extract concerned information from XML document by structural rules, and the other is storing element to make final XML document or store it into database system. For word document converting, we developed OCX based word converting daemon. Helping user to extracting information, we developed script language having native function/variable processing engine extended from XSLT. This system can be used in the area of constructing word document contents DB or providing various information service based on RAW word documents. We really applied it to project management system and project result management system.

• Journal of the Korean Data and Information Science Society
• /
• v.27 no.2
• /
• pp.285-294
• /
• 2016

In general, employment duration is influenced by the individual characteristics (level-1) as well as type of the occupational characteristics (level-2). That is, the data has hierarchical structure in the sense that individual employment duration is influenced by the individual-level variables (level-1) and the job-level (level-2) variables. In this paper, we study the determinants of the employment duration of youth-intern in the SMEs (small and medium enterprises) using Cox's mixed effect model. Major results at level-1 variables are as followings. First, the hazard rate of treatment group is lower than that of control group. Second, the hazard rate of woman is lower than that of man. Also, the hazard rate is lower, for the older and the workers working in the bigger company. Investigation of level-2 variables has shown that random effect for job-level is statistically significant.

• Journal of Korea Spatial Information System Society
• /
• v.11 no.1
• /
• pp.43-54
• /
• 2009

As R&D(Research and Development) is going on actively to develop technologies for the ubiquitous computing environment, which Is the human-oriented future computing environment, GIS dealing with spatio-temporal data is emerging as a promising technology. This also increases the necessity of the middleware for providing services to give interoperability in various heterogeneous environments. The core technologies of the middleware are real-time processing technology of data streams coming unceasingly from positioning systems and data stream processing technology developed for non-spatio-temporal data. However, it has problems in processing queries on spatio-temporal data efficiently. Accordingly, this paper designed and implemented the spatio-temporal middleware that provides interoperability between a mobile spatio-temporal DBMS(DataBase Management System) and a server spatio-temporal MMDBMS(Main Memory DataBase Management System). The spatio-temporal middleware maintains interoperability among heterogeneous devices and guarantees data integrity in query processing through real-time processing of unceasing spatio-temporal data streams and two way synchronization of spatio-temporal DBMSs. In addition, it manages session for the connection of each spatio-temporal DBMS and manages resources for its stable operation. Finally, this paper proved the usability of the spatio-temporal middleware by applying it to a real-time position tracking system.

• Journal of the Korean Society for Library and Information Science
• /
• v.51 no.4
• /
• pp.183-201
• /
• 2017

The purpose of this study was to examine the current staffing practices in public libraries and to analyze the relevance of legal standards of public library staffing. It analyzed the national library statistical data to obtain the national average staffing rate, reviewed related literature to understand the rationales that established the key attributes that construct the current legal standards, and compared the placement rates of the three standards, namely the current legal standards, Korean Library Association's standards, and IFLA staffing standards, to determine the optimacy of the legal standards. It found the current placement rate in the legal standard was only 18.2%, marking the lowest rates among the three compared standards, indicating the current legal standards being unnecessarily high. The study attributes the problem to the structure of the current legal standards that calculate the staffing size based on the building and collection size rather than service populations. The findings of this study suggest a revision of the current standard based on service population while retaining the minimum staffing of three librarians even the smallest public library unit.