• Journal of KIISE:Computing Practices and Letters
• /
• v.14 no.5
• /
• pp.517-521
• /
• 2008

A worm is a malware that propagates quickly from host to host without any human intervention. Need of early worm detection has changed research paradigm from signature based worm detection to the behavioral based detection. To increase effectiveness of proposed solution, in this paper we present mechanism of detection and prevention of worm in distributed fashion. Furthermore, to minimize the worm destruction; upon worm detection we propagate the possible attack aleγt to neighboring nodes in secure and organized manner. Considering worm behavior, our proposed mechanism detects worm cycles and infection chains to detect the sudden change in network performance. And our model neither needs to maintain a huge database of signatures nor needs to have too much computing power, that is why it is very light and simple. So, our proposed scheme is suitable for the ubiquitous environment. Simulation results illustrate better detection and prevention which leads to the reduction of infection rate.

• Journal of Korea Multimedia Society
• /
• v.15 no.8
• /
• pp.1017-1030
• /
• 2012

Most watermarking schemes for video contents protection have been studied to increase watermark's robustness and invisibility against such compressions and many kinds of signal processing after embedding copyright information to the original contents. This paper proposes an active watermarking that infect watermark to contents in the video decoding process using embedded infectious watermark and control signals from a video encoder side. To achieve this algorithm, we design a kernel based watermarking in video encoder side that is possible to recover the original contents and watermark in watermark detection procedure perfectly. And then, by reversible de-watermarking in video decoder side, we design the active watermark infection method using detected watermark and control signal. This means that our system can provide secure re-distributions of video contents without any quality degration and watermark bit error against transcoding or re-encoding processing. By experimental results, we confirmed that the embedded watermark was infected by video contents and codec perfectly without any declines of compression ratio and video quality.

• Journal of Labour Economics
• /
• v.29 no.2
• /
• pp.117-143
• /
• 2006

This paper illuminates the patterns of growth and declines in sizes of union membership in metal, chemical, financial, and auto transport sectors in three distinct periods during the last four decades from 1963 to 2003. This paper also calculates union densities in auto assembly, auto supply, and shipbuilding industries of the metal sector, cement, petroleum refining, and pharmaceutical industries of the chemical sector, private banking industry of the financial sector, and city bus industry of the auto transport sector. Such diversities in both sizes of union membership and union densities among sectors and industries turned out to be associated with attitudes and choices of employers and unions in interaction with sector- and industry-specific economic (growth stage and path), institutional (degrees of government intervention), and social (demographic features of employees and prevailing sizes of firms) environment. Such finding shows that theoretical reasonings on sizes of union membership and union densities across sectors and industries in advanced nations are also relevantly useful to analyze the Korean case.

• Journal of Satellite, Information and Communications
• /
• v.11 no.2
• /
• pp.42-47
• /
• 2016

Due to advances such as photovoltaic power generation and energy storage system, energy self-consumption smart home system in which energy management system is built and energy is generated in house has been actively researched. In particular, due to the instability of the grid after the Fukushima nuclear accident, home system in which generating electricity from photovoltaic, storing and using it in energy storage system was commercialized in Japan. While subsidizing renewable energy projects through a combination of solar and energy storage systems in North America and Europe has expanded home installation. In this paper, we describe development of self-consumption smart home system which is connecting photovoltaic system and energy storage system in home area network and operating it based on real-time price. We implemented automated self-consumption home in which optimizing the use of energy from the power grid with minimal user's intervention.

• Journal of Internet Computing and Services
• /
• v.7 no.4
• /
• pp.67-77
• /
• 2006

Wrappers play an important role in extracting specified information from various sources. Wrapper rules by which information is extracted are often created from the domain-specific knowledge. Domain-specific knowledge helps recognizing the meaning the text representing various entities and values and detecting their formats However, such domain knowledge becomes powerless when value-representing data are not labeled with appropriate textual descriptions or there is nothing but a hyper link when certain text labels or values are expected. In order to alleviate these problems, we propose a probabilistic method for recognizing the entity type, i.e. generating wrapper rules, when there is no label associated with value-representing text. In addition, we have devised a method for using the information reachable by following hyperlinks when textual data are not immediately available on the target web page. Our experimental work shows that the proposed methods help increasing precision of the resulting wrapper, particularly extracting the title information, the most important entity on a web page. The proposed methods can be useful in making a more efficient and correct information extraction system for various sources of information without user intervention.

• Journal of KIISE
• /
• v.43 no.2
• /
• pp.196-203
• /
• 2016

Due to the limitations of budget, resources, and time invested in a project, software requirements should be prioritized and be implemented in order of importance. Existing approaches to prioritizing requirements mostly depend on human decisions. The manual prioritization process is based on intensive interactions with the stakeholders, thus raising the issues of scalability and biased prioritization. To solve these problems, we propose a fully automated requirements prioritization approach, ToMSN (Topic Modeling Stakeholder Needs for requirements prioritization), by topic modeling the stakeholder needs-artifacts earned in the requirements elicitation phase. The requirements dataset of a 30,000-user system was utilized for the performance evaluation. ToMSN showed competitive prioritizing accuracy with existing approaches without human aids, therefore solving scalability and biased prioritization issues.

• Journal of Korean Society for Geospatial Information Science
• /
• v.17 no.1
• /
• pp.43-52
• /
• 2009

LIDAR data, as the source of the 3D information of buildings, are used many modeling fields such as three-dimensional city models in urban planning and the visibility analysis of buildings. This study suggests a methodology, that is characterized by combining image-based and point-based process, for minimizing the user's intervention and automatically extracting building boundary only using the LIDAR data. Image processing methodology is firstly used to separate building and non-building regions from LIDAR data. Moreover, building regions are then classified main roof into remaining parts by the statistical analysis of height values, and the remaining parts are processed separately. Through the experimental results of study areas which exist many types of buildings, for example, apartment-type, stair-type, complex-type, etc. Approximately 90% building boundaries are automatically extracted by the proposed methodology.

• Korean Journal of Construction Engineering and Management
• /
• v.16 no.2
• /
• pp.97-105
• /
• 2015

Building information modeling (BIM)-based construction projects have increased and become more varied, and as such the management of BIM-based facility information is also increasingly important for facility maintenance. Information management, and specifically product data mapping, however, has some problems in the area of manual data entry and does not adequately consider the exchange requirements of facility maintenance. Therefore, it is necessary to introduce a method to improve the management of composite object information for BIM-based facility maintenance so that it can handle construction operation building information exchange (COBie) data for a composite object. Therefore, we present a method to map COBie data to related materials of a composite object. This research contributes to increasing the efficiency and accuracy of the required information mapping between a building model and product data using a BIM library through optimal BIM data adoption. Moreover, it allows for the creation and management of specific product data at the design development phase.

• Journal of Digital Convergence
• /
• v.16 no.1
• /
• pp.271-279
• /
• 2018

Various technologies have been developed to more efficiently share content such as P2P and CDN. These technologies take a common approach that request packets are responded by distributed network nodes, not by a single distributor. Such approaches not only resolve network congestion around content distributors, but also make it possible to distribute content regardless of the system and network status of content distributors. However, when receiving content from distributed nodes/hosts, not from authenticated distributors, users cannot practically identify which node/host sent content to them. Due to this characteristic, various hacking caused by the malicious modification of content is possible. Therefore, to make such approaches more secure, a content authentication technique is required. In this paper, we propose a improved operation of MHT used in CCN for authenticating distributed content. Then we evaluate the proposed method by comparing its performance with the existing technology.

• Journal of KIISE:Computing Practices and Letters
• /
• v.11 no.3
• /
• pp.216-223
• /
• 2005

A computer clock has limits in accuracy and precision affected by its inherent instability, the environment elements, the modification of users, and errors of the system. So the computer clock needs to be synchronized with a standard clock if the computer system requires the precise time processing. The purpose of synchronizing clocks is to provide a global time base throughout a distributed system. Once this time base exists, transactions among members of distributed system can be controlled based on time. This paper discusses the integrated approach to clock synchronization. An embedded system is considered for time synchronization based on the GPS(Global Positioning System) referenced time distribution model. The system uses GPS as standard reference time source and offers UTC(Universal Time Coordinated) through NTP(Network Time Protocol). A clock model is designed and adapted to keep stable time and to provide accurate standard time with precise resolution. Private MIB(Management Information Base) is defined for network management. Implementation results and performance analysis are also presented.